Category Archives: Pathway

Lunasin

Cancer: Colon, breast, liver metastasis

Action: Induces apoptosis, MDR

Lunasin is a peptide found in soy, barley, wheat, and rye, including Glycine max [(L.) Merr.], Hordeum vulgare L., Triticum (L.) genus and Secale cereale L.

Colon Cancer; Metastasis

Lunasin bound with α(5)β(1) integrin and internalized into the nucleus of KM12L4 human colon cancer cells. Lunasin (10µM) inhibited the activation of focal adhesion kinase (FAK) by 28%, 39% and 60% in RKO, HCT-116 and KM12L4 human colon cancer cells, respectively. Lunasin caused an increase in the expression of the inhibitor of kappa B alpha (IκB-α), a decrease in nuclear p50 NF-κB and a reduction in the migration of cancer cells. Lunasin (4mg/kg bw) inhibited metastasis and potentiated the effect of oxaliplatin by reducing the expression of proliferating cell nuclear antigen.

Liver metastatic nodules were reduced from 28 (PBS) to 14 (lunasin, P=0.047) while combination of lunasin and oxaliplatin to 5 (P=0.004). The tumor burden was reduced from 0.13 (PBS) to 0.10 (lunasin, P=0.039) to 0.04 (lunasin+oxaliplatin, P<0.0001). Moreover, lunasin potentiated the effect of oxaliplatin in modifying expression of proteins involved in apoptosis and metastasis including Bax, Bcl-2, IKK-α and p-p65. Lunasin inhibited metastasis of human colon cancer cells by direct binding with α(5)β(1) integrin suppressing FAK/ERK/NF-κB signaling, and potentiated the effect of oxaliplatin in preventing the outgrowth of metastasis (Dia et al., 2011).

Induces Apoptosis

Galvez et al. (2001) demonstrated previously that transfection of mammalian cells with the lunasin gene arrests mitosis, leading to cell death. Here they show that exogenous application of the lunasin peptide inhibits chemical carcinogen-induced transformation of murine fibroblast cells to cancerous foci. The results suggest a mechanism whereby lunasin selectively induces apoptosis, mostly in cells undergoing transformation, by preventing histone acetylation. In support of this, lunasin selectively induces apoptosis in E1A-transfected cells but not in nontransformed cells. Finally, in the SENCAR mouse skin cancer model, dermal application of lunasin (250 microg/week) reduces skin tumor incidence by approximately 70%, decreases tumor yield/mouse, and delays the appearance of tumors by 2 weeks relative to the positive control. These results point to the role of lunasin as a new chemo-preventive agent that functions possibly via a chromatin modification mechanism.

Breast Cancer

Combinations of two or more chemo-preventive agents are currently being used to achieve greater inhibitory effects on breast cancer cells. This study reveals that both aspirin and lunasin inhibit, in a dose-dependent manner, human estrogen-independent breast cancer MDA-MB-231 cell proliferation.

These compounds arrest the cell-cycle in the S- and G1-phases, respectively, acting synergistically to induce apoptosis. The cell growth-inhibitory effect of a lunasin/aspirin combination is achieved, at least partially, by modulating the expression of genes encoding G1 and S-phase regulatory proteins. Lunasin/aspirin therapy exerts its potent pro-apoptotic effect, at least partially achieved through modulating the extrinsic-apoptosis dependent pathway.

Therefore, our results suggest that a combination of these two compounds is a promising strategy to prevent/treat breast cancer (Hsieh et al., 2010).

Colon Cancer; MDR

Various human colon cancer cell lines which underwent metastasis were evaluated in vitro using cell flow cytometry and fluorescence microscopy. Lunasin cytotoxicity to different colon cancer cells correlated with the expression of α5b1 integrin was investigated, being most potent to KM12L4 cells (IC50 = 13 µM). Lunasin arrested cell-cycle at G2/M phase with concomitant increase in the expression of cyclin-dependent kinase inhibitors p21 and p27. Lunasin (5–25 µM) activated the apoptotic mitochondrial pathway as evidenced by changes in the expressions of Bcl-2, Bax, nuclear clusterin, cytochrome c and caspase-3 in KM12L4 and KM12L4-OxR.

Lunasin increased the activity of initiator caspase-9 leading to the activation of caspase-3 and also modified the expression of human extracellular matrix and adhesion genes, down-regulating integrin α5, SELE, MMP10, integrin β2 and COL6A1 by 5.01-, 6.53-, 7.71-, 8.19- and 10.10-fold, respectively, while up-regulating COL12A1 by 11.61-fold. Lunasin can be used in cases where resistance to chemotherapy developed (Dia et al., 2011).

References

Dia VP, Gonzalez de Mejia E. (2011). Lunasin potentiates the effect of oxaliplatin preventing outgrowth of colon cancer metastasis, binds to α5β1 integrin and suppresses FAK/ERK/NF-κ B signaling, Cancer Lett, 313(2):167-80.


Dia VP, Gonzalez de Mejia E. (2011). Lunasin induces apoptosis and modifies the expression of genes associated with extracellular matrix and cell adhesion in human metastatic colon cancer cells. Mol Nutr Food Res, 55(4):623-34. doi: 10.1002/mnfr.201000419.


Galvez AF, Chen N, Macasieb J, de Lumen BO. (2001). Chemo-preventive property of a soybean peptide (lunasin) that binds to deacetylated histones and inhibits acetylation. Cancer Res, 61(20):7473-8.


Hsieh CC, Hern‡ndez-Ledesma B, de Lumen BO. (2010). Lunasin, a novel seed peptide, sensitizes human breast cancer MDA-MB-231 cells to aspirin-arrested cell-cycle and induced apoptosis. Chem Biol Interact, 186(2):127-34. doi: 10.1016/j.cbi.2010.04.027.

Koetjapic acid

Cancer: none noted

Action: Anti-angiogenic

Koetjapic acid is isolated from Sandoricum koetjape (Merr.).

Angiogenesis, the formation of new blood vessels, has become an important target in cancer therapy. Angiogenesis plays an important role in tumor growth and metastasis. The solvent extract of this plant species was shown previously to have strong anti-angiogenic activity; however the active ingredient(s) that conferred the biological activity, and the mode of action, were not established. Given the high concentration of koetjapic acid (KA) in S. koetjape, an attempt has been made in this study to investigate the anti-angiogenic properties of KA.

Treatment with 10-50 mug/ml KA resulted in dose-dependent inhibition of new blood vessel growth in ex vivo rat aortic ring assay. KA was found to be non-cytotoxic against HUVECs with IC50 40.97 +/- 0.37 mug/ml. KA inhibited major angiogenesis process steps, endothelial cell migration and differentiation as well as VEGF expression. The non-cytotoxic compound, KA, may be a potent anti-angiogenic agent and its activity may be attributed to inhibition of endothelial cells migration and differentiation as well VEGF suppression (Nassar et al., 2011).

References

Nassar ZD, Aisha AFAA, Ahamed MBK, et al. (2011). Anti-angiogenic properties of Koetjapic acid, a natural triterpene isolated from Sandoricum koetjaoe Merr. Cancer Cell International., 11:12. doi:10.1186/1475-2867-11-12.

Indirubin

Cancer:
Chronic myelogenous leukemia, lung, breast, head and neck, prostate, acute myeloid leukemia, prostate

Action: Aryl hydrocarbon Receptor (AhR) regulator, inhibits angiogenesis

Indirubin is the active component of many plants from the Isatis (L.) genus, including Isatis tinctoria (L.).

Indirubin is the active ingredient of Danggui Longhui Wan, a mixture of plants that is used in traditional Chinese medicine to treat chronic diseases. Indirubin and its analogues are potent inhibitors of cyclin-dependent kinases (CDKs). The crystal structure of CDK2 in complex with indirubin derivatives shows that indirubin interacts with the kinase's ATP-binding site through van der Waals interactions and three hydrogen bonds. Indirubin-3'-monoxime inhibits the proliferation of a large range of cells, mainly through arresting the cells in the G2/M phase of the cell-cycle. These results have implications for therapeutic optimization of indigoids (Hoessel et al., 1999).

Formula; Huang Lian (Rhizoma Coptidis Recens), Huang Qin (Radix Scutellariae Baicalensis), Huang Bai (Cortex Phellodendri), Zhi Zi (Fructus Gardeniae Jasminoidis), Dang Gui (Radix Angelicae Sinensis), Lu Hui (Herba Aloes), Long Dan Cao (Radix Gentianae Longdancao), Da Huang (Radix et Rhizoma Rhei), Mu Xiang (Radix Aucklandiae Lappae), Qing Dai (Indigo Pulverata Levis), She Xiang (Secretio Moschus)

Leukemia

Indirubin, a 3, 2' bisindole isomer of indigo was originally identified as the active principle of a traditional Chinese preparation and has been proven to exhibit anti-leukemic effectiveness in chronic myelocytic leukemia. Indirubin was detected to represent a novel lead structure with potent inhibitory potential towards cyclin-dependent kinases (CDKs) resulting from high affinity binding into the enzymes ATP binding site. This seminal finding triggered research to improve the pharmacological activities of the parent molecule within comprehensive structure-activity studies. Molecular modifications made novel anti-cancer compounds accessible with strongly improved CDK inhibitory potential and with broad-spectrum anti-tumor activity.

This novel family of compounds holds strong promise for clinical anti-cancer activity and might be useful also in several important non-cancer indications, including Alzheimer's disease or diabetes (Eisenbrand et al., 2004).

Aryl Hydrocarbon Receptor (AhR) Regulator; Breast Cancer

The aryl hydrocarbon receptor (AhR), when activated by exogenous ligands such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), regulates expression of several phase I and phase II enzymes and is also involved in the regulation of cell proliferation. One putative endogenous ligand is indirubin, which was recently identified in human urine and bovine serum. We determined the effect of indirubin in MCF-7 breast cancer cells on induction of the activities of cytochromes P450 (CYP) 1A1 and 1B1. With 4 hours exposure, the effects of indirubin and TCDD at 10nM on CYP activity were comparable, but the effects of indirubin, unlike those of TCDD, were transitory. Indirubin-induced ethoxyresorufin-O-deethylase activity was maximal by 6–9 hours post-exposure and had disappeared by 24 hours, whereas TCDD-induced activities remained elevated for at least 72 hours.

Thus, if indirubin is an endogenous AhR ligand, then AhR-mediated signaling by indirubin is likely to be transient and tightly controlled by the ability of indirubin to induce CYP1A1 and CYP1B1, and hence its own metabolism (Spink et al., 2003).

Chronic Myelogenous Leukemia (CML)

Indirubin is the major active anti-tumor component of a traditional Chinese herbal medicine used for treatment of chronic myelogenous leukemia (CML). In a study investigating its mechanism of action, indirubin derivatives (IRDs) were found to potently inhibit Signal Transducer and Activator of Transcription 5 (Stat5) protein in CML cells.

Compound E804, which is the most potent in this series of IRDs, blocked Stat5 signaling in human K562 CML cells, imatinib-resistant human KCL-22 CML cells expressing the T315I mutant Bcr-Abl (KCL-22M), and CD34-positive primary CML cells from patients.

In sum, these findings identify IRDs as potent inhibitors of the SFK/Stat5 signaling pathway downstream of Bcr-Abl, leading to apoptosis of K562, KCL-22M and primary CML cells. IRDs represent a promising structural class for development of new therapeutics for wild type or T315I mutant Bcr-Abl-positive CML patients (Nam et al., 2012).

Lung Cancer

A novel indirubin derivative, 5'-nitro-indirubinoxime (5'-NIO), exhibits a strong anti-cancer activity against human cancer cells. Here, the 5'-NIO-mediated G1 cell-cycle arrest in lung cancer cells was associated with a decrease in protein levels of polo-like kinase 1 (Plk1) and peptidyl-prolyl cis/trans isomerase Pin1. These findings suggest that 5'-NIO have potential anti-cancer efficacy through the inhibition of Plk1 or/and Pin1 expression (Yoon et al., 2012).

The control lung tissue showed a normal architecture with clear alveolar spaces. Interestingly, the indirubin-3-monoxime treated groups showed reduced adenocarcinoma with appearance of alveolar spaces. Transmission Electron Microscopic (TEM) studies of lung sections of [B(α)P]-induced lung cancer mice showed the presence of phaemorphic cells with dense granules and increased mitochondria.

The lung sections of mice treated with indirubin-3-monoxime showed the presence of shrunken, fragmented, and condensed nuclei implying apoptosis. The effects were dose-dependent and prominent in 10 mg/kg/5 d/week groups, suggesting the therapeutic role of indirubin analogue against this deadly human malignancy. These results indicate that indirubin-3-monoxime brings anti-tumor effect against [B(α)P]-induced lung cancer by its apoptotic action in A/J mice (Ravichandran et al., 2010).

Head and Neck Cancer

The effects of 5'-nitro-indirubinoxime (5'-NIO), an indirubin derivative, on metastasis of head and neck cancer cells were investigated and the underlying molecular mechanisms involved in this process explored.

After treatment of head and neck cancer cells with 5'-NIO, cell metastatic behaviors such as colony formation, invasion, and migration were inhibited in a concentration-dependent manner. 5'-NIO inhibited the beta1 Integrin/FAK/Akt pathway which can then facilitate invasion and/or migration of cancer cells through the extracellular matrix (ECM). Moreover, treatment of head and neck cancer cell with Integrin β1 siRNA or FAK inhibitor effectively inhibited the invasion and migration, suggesting their regulatory role in invasiveness and migration of head and neck cancer cells. It was concluded that 5'-NIO inhibits the metastatic ability of head and neck cancer cells by blocking the Integrin β1/FAK/Akt pathway (Kim et al., 2011).

Prostate Cancer; Inhibits Angiogenesis

Indirubin, the active component of a traditional Chinese herbal medicine, Banlangen, has been shown to exhibit anti-tumor and anti-inflammation effects; however, its role in tumor angiogenesis, the key step involved in tumor growth and metastasis, and the involved molecular mechanism is unknown.

To address this shortfall in the existing research, it was identified that indirubin inhibited prostate tumor growth through inhibiting tumor angiogenesis. It was found that indirubin inhibited angiogenesis in vivo. The inhibition activity of indirubin in endothelial cell migration, tube formation and cell survival in vitro has also been shown. Furthermore, indirubin suppressed vascular endothelial growth factor receptor 2-mediated Janus kinase (JAK)/STAT3 signaling pathway. This study provided the first evidence for anti-tumor angiogenesis activity of indirubin and the related molecular mechanism.

These investigations suggest that indirubin is a potential drug candidate for angiogenesis-related diseases (Zhang et al., 2011).

Acute Myeloid Leukemia

Indirubin derivatives were identified as potent FLT3 tyrosine kinase inhibitors with anti-proliferative activity at acute myeloid leukemic cell lines, RS4;11 and MV4;11 which express FLT3-WT and FLT3-ITD mutation, respectively. Among several 5 and 5'-substituted indirubin derivatives, 5-fluoro analog, 13 exhibited potent inhibitory activity at FLT3 (IC(50)=15 nM) with more than 100-fold selectivity versus 6 other kinases and potent anti-proliferative effect for MV4;11 cells (IC(50)=72 nM) with 30-fold selectivity versus RS4;11 cells.

Cell cycle analysis indicated that compound 13 induced cell-cycle arrest at G(0)/G(1) phase in MV4;11 cells (Choi et al., 2010).

References

Choi SJ, Moon MJ, Lee SD, et al. (2010). Indirubin derivatives as potent FLT3 inhibitors with anti-proliferative activity of acute myeloid leukemic cells. Bioorg Med Chem Lett, 20(6):2033-7.


Eisenbrand G, Hippe F, Jakobs S, Muehlbeyer S. (2004). Molecular mechanisms of indirubin and its derivatives: novel anti-cancer molecules with their origin in traditional Chinese phytomedicine. J Cancer Res Clin Oncol, 130(11):627-35


Hoessel R, Leclerc S, Endicott JA, et al. (1999). Indirubin, the active constituent of a Chinese antileukaemia medicine, inhibits cyclin-dependent kinases. Nat Cell Biol, 1(1):60-7.


Kim SA, Kwon SM, Kim JA, et al. (2011). 5'-Nitro-indirubinoxime, an indirubin derivative, suppresses metastatic ability of human head and neck cancer cells through the inhibition of Integrin β 1/FAK/Akt signaling. Cancer Lett, 306(2):197-204.


Nam S, Scuto A, Yang F, et al. (2012). Indirubin derivatives induce apoptosis of chronic myelogenous leukemia cells involving inhibition of Stat5 signaling. Mol Oncol, 6(3):276-83.


Ravichandran K, Pal A, Ravichandran R. (2010). Effect of indirubin-3-monoxime against lung cancer as evaluated by histological and transmission electron microscopic studies. Microsc Res Tech, 73(11):1053-8.


Spink BC, Hussain MM, Katz BH, Eisele L, Spink DC. (2003). Transient induction of cytochromes P450 1A1 and 1B1 in MCF-7 human breast cancer cells by indirubin. Biochem Pharmacol, 66(12):2313-21.


Yoon HE, Kim SA, Choi HS, et al. (2012). Inhibition of Plk1 and Pin1 by 5'-nitro-indirubinoxime suppresses human lung cancer cells. Cancer Lett, 316(1):97-104.


Zhang X, Song Y, Wu Y, et al. (2011). Indirubin inhibits tumor growth by anti-tumor angiogenesis via blocking VEGFR2-mediated JAK/STAT3 signaling in endothelial cell. Int J Cancer, 129(10):2502-11. doi: 10.1002/ijc.25909.

Icaritin

Cancer:
Endometrial., chronic myeloid leukemia, prostate, breast

Action: Radio-sensitizer, cell-cycle arrest, ER modulator

Icaritin is a compound in several species of the genus Epimedium (L.).

Cell-cycle Arrest

Icariin and icaritin with prenyl group have been demonstrated to have selective estrogen receptor modulating activities. Icaritin-induced growth inhibition was associated with G(1) arrest (P<0.05), and G(2)-M arrest depending upon doses. Consistent with G(1) arrest, icaritin increased protein expressions of pRb, p27(Kip1) and p16(Ink4a), while showing decrease in phosphorylated pRb, Cyclin D1 and CDK4.

Comparatively, icariin has much lower effects on PC-3 cells and showed only weak G(1) arrest, suggesting a possible structure-activity relationship. These findings suggested a novel anti-cancer efficacy of icaritin mediated selectively via induction of cell-cycle arrest but not associated with estrogen receptors in PC-3 cells (Huang et al., 2007).

Estrogen Receptor (ER) Modulator; Endometrial Cancer

Icaritin has selective estrogen receptor (ER) modulating activities, and posseses anti-tumor activity. The effect of icaritin on cell growth of human endometrial cancer Hec1A cells was investigated and it was found that icaritin potently inhibited proliferation of Hec1A cells. Icaritin also induced cell apoptosis accompanied by activation of caspases. Icaritin treatment also induced expression of pro-apoptotic protein Bax with a concomitant decrease of Bcl-2 expression.

These results demonstrate that icaritin induced sustained ERK 1/2 activation and inhibited growth of endometrial cancer Hec1A cells, and provided a rationale for preclinical and clinical evaluation of icaritin for endometrial cancer therapy (Tong et al., 2011).

Breast cancer

In research carried out to probe breast cancer cell growth mechanisms, icaritin has been found to strongly inhibit the growth of breast cancer MDA-MB-453 and MCF7 cells. At concentrations of 2–3 µM, icaritin induced cell-cycle arrest at the G2/M phase accompanied by a down-regulation of the expression levels of the G2/M regulatory proteins such as cyclinB, cdc2 and cdc25C.

Icaritin at concentrations of 4–5 µM, however, induced apoptotic cell death. In addition, icaritin also induced a sustained phosphorylation of extracellular signal-regulated kinase (ERK) in these breast cancer cells.

Icaritin more potently inhibited growth of the breast cancer stem/progenitor cells compared to anti-estrogen tamoxifen. These results indicate that icaritin is a potent growth inhibitor for breast cancer cells and provides a rationale for preclinical and clinical evaluations of icaritin for breast cancer therapy (Guo et al., 2011).

Radio-sensitizer

The combination of Icaritin at 3 µM or 6 µM with 6 or 8 Gy of ionizing radiation (IR) in the clonogenic assay yielded an ER (enhancement ratio) of 1.18 or 1.28, CI (combination index) of 0.38 or 0.19 and DRI (dose reducing index) of 2.51 or 5.07, respectively. These findings strongly suggest that Icaritin exerted a synergistic killing effect with radiation on the tumor cells. It suppressed angiogenesis in chick embryo chorioallantoic membrane (CAM) assay. These results, taken together, indicate Icaritin is a new radio-sensitizer and can enhance anti-cancer effect of IR or other therapies (Hong et al., 2013).

Chronic Myeloid Leukemia (CML)

The mechanism of anti-leukemia for Icaritin is involved in the regulation of Bcr/Abl downstream signaling. Icaritin may be useful for an alternative therapeutic choice of Imatinib-resistant forms of CML. Icaritin potently inhibited proliferation of K562 cells (IC50 was 8 µM) and primary CML cells (IC50 was 13.4 µM for CML-CP and 18 µM for CML-BC), induced CML cells apoptosis, and promoted the erythroid differentiation of K562 cells in a time-dependent manner. Furthermore, Icaritin was able to suppress the growth of primary CD34+ leukemia cells (CML) and Imatinib-resistant cells, and to induce apoptosis (Zhu et al., 2011).

References

Guo YM, Zhang XT, Meng J, Wang ZY. (2011). An anti-cancer agent icaritin induces sustained activation of the extracellular signal-regulated kinase (ERK) pathway and inhibits growth of breast cancer cells. European Journal of Pharmacology, 658(2–3):114–122. doi:10.1016/j.ejphar.2011.02.005.


Hong J, Zhang Z, Lv W, et al. (2013). Icaritin Synergistically Enhances the Radiosensitivity of 4T1 Breast Cancer Cells. PLoS One, 8(8):e71347. doi: 10.1371/journal.pone.0071347.


Huang X, Zhu D, Lou Y. (2007). A novel anti-cancer agent, icaritin, induced cell growth inhibition, G1 arrest and mitochondrial transmembrane potential drop in human prostate carcinoma PC-3 cells. Eur J Pharmacol, 564(1-3):26-36.


Tong JS, Zhang QH, Huang X, et al. (2011). Icaritin Causes Sustained ERK1/2 Activation and Induces Apoptosis in Human Endometrial Cancer Cells. PLoS ONE, 6(3): e16781. doi:10.1371/journal.pone.0016781.


Zhu JF, Li ZJ, Zhang GS, et al. (2011). Icaritin shows potent anti-leukemia activity on chronic myeloid leukemia in vitro and in vivo by regulating MAPK/ERK/JNK and JAK2/STAT3 /AKT signalings. PLoS One, 6(8):e23720. doi: 10.1371/journal.pone.0023720.

I3C

Cancer: Prostate

Action: Inhibits telomerase activity, anti-cancer

Indole-3-carbinol (I3C) is a phytochemical with anti-carcinogenic properties. Telomerase activity is key in carcinogenesis. The effect of I3C on telomerase was investigated in human prostate cancer cell lines LNCaP and PC3. Cells were treated with I3C at 100 and 250 µM with and without 10-50 µM diethylstilbestrol (DES). Telomerase activity was performed using TRAPaze Telomerase Detection Kit, and hTERT gene expression by real time quantitative RT-PCR. I3C (250 µM) inhibited telomerase activity and mRNA expression of hTERT in LNCaP and PC3 cells. I3C at 250 µM combined with any concentration of DES was cytotoxic to LNCaP. Telomerase activity in PC3 cells with 250 µM of I3C and 25 or 50 µM of DES was significantly reduced or inhibited, respectively.

I3C combined with DES reduced PC3 viability and eliminated LNCaP cells. I3C significantly inhibited telomerase activity and hTERT mRNA expression in LNCaP and PC3 cells. Combination of I3C and DES enhanced the inhibitory effect on telomerase activity, gene expression, and cell viability. These results implied that I3C and DES combined might help in prostate cancer treatment (Adler et al., 2011).

Reference

Adler S, Rashid G, Klein A. (2011). Indole-3-carbinol inhibits telomerase activity and gene expression in prostate cancer cell lines. Anti-cancer Res, 31(11):3733-7.

Hispolon

Cancer: Bladder, breast, liver, gastric

Action: Anti-inflammatory, cytostatic, cytotoxic, pro-oxidative, anti-proliferative

Hispolon is an active phenolic compound of Phellinus igniarius , a mushroom that has recently been shown to have anti-oxidant, anti-inflammatory, and anti-cancer activities.

Liver Cancer

Hispolon inhibited cellular growth of Hep3B cells in a time-dependent and dose-dependent manner, through the induction of cell-cycle arrest at S phase measured using flow cytometric analysis and apoptotic cell death, as demonstrated by DNA laddering. Exposure of Hep3B cells to hispolon resulted in apoptosis as evidenced by caspase activation, PARP cleavage, and DNA fragmentation. Hispolon treatment also activated JNK, p38 MAPK, and ERK expression. Inhibitors of ERK (PB98095), but not those of JNK (SP600125) and p38 MAPK (SB203580), suppressed hispolon-induced S-phase arrest and apoptosis in Hep3B cells.

These findings establish a mechanistic link between the MAPK pathway and hispolon-induced cell-cycle arrest and apoptosis in Hep3B cells (Huang et al., 2011).

Gastric Cancer, Breast Cancer, Bladder Cancer

Hispolon extracted from Phellinus species was found to induce epidermoid and gastric cancer cell apoptosis. Hispolon has also been found to inhibit breast and bladder cancer cell growth, regardless of p53 status. Furthermore, p21(WAF1), a cyclin-dependent kinase inhibitor, was elevated in hispolon-treated cells. MDM2, a negative regulator of p21(WAF1), was ubiquitinated and degraded after hispolon treatment.

Lu et al. (2009) also found that activated ERK1/2 (extracellular signal-regulated kinase1/2) was recruited to MDM2 and involved in mediating MDM2 ubiquitination. The results indicated that cells with higher ERK1/2 activity were more sensitive to hispolon. In addition, hispolon-induced caspase-7 cleavage was inhibited by the ERK1/2 inhibitor, U0126.

In conclusion, hispolon ubiquitinates and down-regulates MDM2 via MDM2-recruited activated ERK1/2. Therefore, hispolon may be a potential anti-tumor agent in breast and bladder cancers.

Gastric Cancer

The efficacy of hispolon in human gastric cancer cells and cell death mechanism was explored. Hispolon induced ROS-mediated apoptosis in gastric cancer cells and was more toxic toward gastric cancer cells than toward normal gastric cells, suggesting greater susceptibility of the malignant cells.

The mechanism of hispolon-induced apoptosis was that hispolon abrogated the glutathione anti-oxidant system and caused massive ROS accumulation in gastric cancer cells. Excessive ROS caused oxidative damage to the mitochondrial membranes and impaired the membrane integrity, leading to cytochrome c release, caspase activation, and apoptosis. Furthermore, hispolon potentiated the cytotoxicity of chemotherapeutic agents used in the clinical management of gastric cancer.

These results suggest that hispolon could be useful for the treatment of gastric cancer either as a single agent or in combination with other anti-cancer agents (Chen et al., 2008).

Anti-proliferative Activity

Hispolon, which lacks one aromatic unit in relation to curcumin, exhibits enhanced anti-inflammatory and anti-proliferative activities. Dehydroxy hispolon was least potent for all three activities. Overall the results indicate that the substitution of a hydroxyl group for a methoxy group at the meta positions of the phenyl rings in curcumin significantly enhanced the anti-inflammatory activity, and the removal of phenyl ring at the 7(th) position of the heptadiene back bone and addition of hydroxyl group significantly increased the anti-proliferative activity of curcumin and hispolon (Ravindran et al., 2010).

References

Chen W, Zhao Z, Li L, et al. (2008). Hispolon induces apoptosis in human gastric cancer cells through a ROS-mediated mitochondrial pathway. Free Radic Biol Med, 45(1):60-72. doi: 10.1016/j.freeradbiomed.2008.03.013.


Huang GJ, Deng JS, Huang SS, Hu ML. (2011). Hispolon induces apoptosis and cell-cycle arrest of human hepatocellular carcinoma Hep3B cells by modulating ERK phosphorylation. J Agric Food Chem, 59(13):7104-13. doi: 10.1021/jf201289e.


Lu TL, Huang GJ, Lu TJ, et al. (2009). Hispolon from Phellinus linteus has anti-proliferative effects via MDM2-recruited ERK1/2 activity in breast and bladder cancer cells. Food Chem Toxicol, 47(8):2013-21. doi: 10.1016/j.fct.2009.05.023.


Ravindran J, Subbaraju GV, Ramani MV, et al. (2010). Bisdemethylcurcumin and structurally related hispolon analogues of curcumin exhibit enhanced prooxidant, anti-proliferative and anti-inflammatory activities in vitro. Biochem Pharmacol, 79(11):1658-66. doi: 10.1016/j.bcp.2010.01.033.

Hedyotis Diffusa Extract

Cancer: Colon

Action: CYP3A4 induction, inhibits angiogenesis

Hedyotis diffusa is a herb native to East Asia, particularly China, Japan, and Nepal.

Inhibition of tumor angiogenesis has become an attractive target of anti-cancer chemotherapy. However, drug resistance and cytotoxicity against non-tumor-associated endothelial cells limit the long-term use and the therapeutic effectiveness of angiogenesis inhibitors, thus increasing the necessity for the development of multi-target agents with minimal side effects. Hedyotis Diffusa Willd (EEHDW) has long been used as an important component in several TCM formulas to treat various types of cancer.

Inhibits Angiogenesis

The angiogenic effects of the ethanol extract of EEHDW were investigated, in order to find a molecular mechanism for its anti-cancer activity. It was found that EEHDW inhibited angiogenesis in vivo in chick embryo chorioallantoic membrane (CAM). In addition, EEHDW dose- and time-dependently inhibited the proliferation of human umbilical vein endothelial cells (HUVEC) by blocking the cell-cycle G1 to S progression.

Moreover, EEHDW inhibited the migration and tube formation of HUVECs. Furthermore, EEHDW treatment down-regulated the mRNA and protein expression levels of VEGF-A in HT-29 human colon carcinoma cells and HUVECs. These findings suggest that inhibiting tumor angiogenesis is one of the mechanisms by which EEHDW is involved in cancer therapy (Lin et al., 2011).

Colorectal Cancer

Hedyotis diffusa Willd has been used as a major component in several Chinese medicine formulas for the clinical treatment of colorectal cancer (CRC). The ethanol extract of Hedyotis diffusa Willd (EEHDW) reduced tumor volume and tumor weight, and suppressed STAT3 phosphorylation in tumor tissues, which in turn resulted in the promotion of cancer cell apoptosis and inhibition of proliferation. Moreover, EEHDW treatment altered the expression pattern of several important target genes of the STAT3 signaling pathway, i.e., decreased expression of Cyclin D1, CDK4 and Bcl-2 as well as up-regulated p21 and Bax (Cai et al., 2012).

EEHDW reduced HT-29 cell viability and survival in a dose- and time-dependent manner. Lin et al. (2012) observed that EEHDW treatment blocked the cell-cycle, preventing G1 to S progression, and reduced mRNA expression of pro-proliferative PCNA, Cyclin D1 and CDK4, but increased that of anti-proliferative p21 (Lin et al., 2012).

Recently, Lin et al. (2013) reported that HDW could inhibit colorectal cancer growth in vivo and in vitro via suppression of the STAT3 pathway. EEHDW could significantly reduce intratumoral microvessel density (MVD), indicating its activity of anti-tumor angiogenesis in vivo. EEHDW suppressed the activation of SHH signaling in CRC xenograft tumors since it significantly decreased the expression of key mediators of SHH pathway. EEHDW treatment inhibited the expression of the critical SHH signaling target gene VEGF-A as well as its specific receptor VEGFR2 (Lin et al., 2013).

CYP3A4 Induction

Patients are warned against the concomitant use of Oldenlandia diffusa and Rehmannia glutinosa, which could result in induction of CYP3A4, leading to a reduced efficacy of drugs that are CYP3A4 substrates and have a narrow therapeutic window (Lau et al., 2013).

References

Cai Q, Lin J, Wei L, Zhang L, et al. (2012). Hedyotis diffusa Willd Inhibits Colorectal Cancer Growth in Vivo via Inhibition of STAT3 Signaling Pathway. Int J Mol Sci, 13(5):6117-28. doi: 10.3390/ijms13056117.


Lau C, Mooiman KD, Maas-Bakker RF, et al. (2013). Effect of Chinese herbs on CYP3A4 activity and expression in vitro. J Ethnopharmacol, 149(2):543-9. doi: 10.1016/j.jep.2013.07.014.


Lin J, Wei L, Xu W, et al. (2011). Effect of Hedyotis Diffusa Willd extract on tumor angiogenesis. Mol Med Report, 4(6):1283-8. doi: 10.3892/mmr.2011.577.


Lin M, Lin J, Wei L, et al. (2012). Hedyotis diffusa Willd extract inhibits HT-29 cell proliferation via cell-cycle arrest. Exp Ther Med, 4(2):307-310.


Lin J, Wei L, Shen A, et al. (2013). Hedyotis diffusa Willd extract suppresses Sonic hedgehog signaling leading to the inhibition of colorectal cancer angiogenesis. Int J Oncol, 42(2):651-6. doi: 10.3892/ijo.2012.1753.

Gypenosides

Cancer: Leukemia, colorectal., oral., esophageal

Action: Apoptosis,inhibits cell proliferation and migration

Gypenosides (Gyp), found in Gynostemma pentaphyllum Makino [(Thunb) Makino], have been used as folk medicine for centuries and have exhibited diverse pharmacological effects, including anti-leukemia effects in vitro and in vivo.

Gyp have been used to examine effects on cell viability, cell-cycle, and induction of apoptosis in vitro. They were administered in the diet to mice injected with WEHI-3 cells in vivo. Gyp inhibited the growth of WEHI-3 cells. These effects were associated with the induction of G0/G1 arrest, morphological changes, DNA fragmentation, and increased sub-G1 phase. Gyp promoted the production of reactive oxygen species, increased Ca2+ levels, and induced the depolarization of the mitochondrial membrane potential.

The effects of Gyp were dose- and time-dependent. Moreover, Gyp increased levels of the pro-apoptotic protein Bax, reduced levels of the anti-apoptotic proteins Bcl-2, and stimulated release of cytochrome c, AIF (apoptosis-inducing factor), and Endo G (endonuclease G) from mitochondria. The levels of GADD153, GRP78, ATF6-α, and ATF4-α were increased by Gyp, resulting in ER (endoplasmic reticular) stress in WEHI-3 cells. Oral consumption of Gyp increased the survival rate of mice injected with WEHI-3 cells used as a mouse model of leukemia.

Results of these experiments provide new information on understanding mechanisms of Gyp-induced effects on cell-cycle arrest and apoptosis in vitro and in an in vivo animal model (Hsu et al., 2011).

Inhibits Cell Proliferation and Migration

Results indicated that Gypenosides (Gyp) inhibited cell proliferation and migration in SW620 and Eca-109 cells in dose- and time-dependent manner. Gyp elevated intracellular ROS level, decreased the Δψ m, and induced apoptotic morphology such as cell shrinkage and chromatin condensation, suggesting oxidative stress and mitochondria-dependent cell apoptosis that might be involved in Gyp-induced cell viability loss in SW620 and Eca-109 cells. The findings indicate Gyp may have valuable application in clinical colon cancer and esophageal cancer treatments (Yan et al., 2013).

Gyp-induced cell death occurs through caspase-dependent and caspase-independent apoptotic signaling pathways, and the compound reduced tumor size in a xenograft nu/nu mouse model of oral cancer.

Gyp induced morphological changes, decreased the percentage of viable cells, caused G0/G1 phase arrest, and triggered apoptotic cell death in SAS cells. Cell-cycle arrest induced by Gyp was associated with apoptosis. The production of ROS, increased intracellular Ca(2+) levels, and the depolarization of ΔΨ(m) were observed. Gyp increased levels of the pro-apoptotic protein Bax but inhibited the levels of the anti-apoptotic proteins Bcl-2 and Bcl-xl. Gyp also stimulated the release of cytochrome c and Endo G. Translocation of GADD153 to the nucleus was stimulated by Gyp. Gyp in vivo attenuated the size and volume of solid tumors in a murine xenograft model of oral cancer (Lu et al., 2012).

Cell-cycle Arrest

Lin et al. (2011) have shown that gypenosides (Gyp) induced cell-cycle arrest and apoptosis in many human cancer cell lines. In the present study the effects of Gyp on cell morphological changes and viability, cell-cycle arrest and induction of apoptosis in vitro and effects on Gyp in an in vivo murine xenograft model were demonstrated. Results indicated that Gyp induced morphological changes, decreased cell viability, induced G0/G1 arrest, DNA fragmentation and apoptosis (sub-G1 phase) in HL-60 cells. Gyp increased reactive oxygen species production and Ca(2+) levels but reduced mitochondrial membrane potential in a dose- and time-dependent manner.

Oral consumption of Gyp reduced tumor size of HL-60 cell xenograft mode mice in vivo. These results provide new information on understanding mechanisms by which Gyp induces cell-cycle arrest and apoptosis in vitro and in vivo (Lin et al., 2011).

References

Hsu HY, Yang JS, Lu KW, et al. (2011). An Experimental Study on the Anti-leukemia Effects of Gypenosides In Vitro and In Vivo. Integr Cancer Ther, 10(1):101-12. doi: 10.1177/1534735410377198.


Lin JJ, Hsu HY, Yang JS, et al. (2011). Molecular evidence of anti-leukemia activity of gypenosides on human myeloid leukemia HL-60 cells in vitro and in vivo using a HL-60 cells murine xenograft model. Phytomedicine,18(12):1075-85. doi: 10.1016/j.phymed.2011.03.009.


Lu KW, Chen JC, Lai TY, et al. (2012). Gypenosides suppress growth of human oral cancer SAS cells in vitro and in a murine xenograft model: the role of apoptosis mediated by caspase-dependent and caspase-independent pathways. Integr Cancer Ther, 11(2):129-40. doi: 10.1177/1534735411403306.


Yan H, Wang X, Wang Y, Wang P, Xiao Y. (2013). Antiproliferation and anti-migration induced by gypenosides in human colon cancer SW620 and esophageal cancer Eca-109 cells. Hum Exp Toxicol.

Guggulsterones

Cancer: Leukemia, cervical cancer

Action: MDR

Guggulsterones are isolated from Commiphora wightii [(Arn.) Bhandari].

Leukemia

The anti-leukemic effects of three isomeric pregnadienedione steroids, cis-guggulsterone, trans-guggulsterone, and 16-dehydroprogesterone, were investigated in HL60 and U937 cells as well as in primary leukemic blasts in culture. Results showed that all three compounds inhibited the proliferation of HL60 and U937 cells, with IC50s ranging from 3.6 to 10.9 µmol/L after treatment for 6 days. These growth-inhibitory effects correlated with externalization of phosphatidylserine and loss of mitochondrial membrane potential., suggesting that these isomeric steroids induce apoptosis in leukemia cells. z-VAD-fmk prevented phosphatidylserine externalization but not mitochondrial membrane potential loss, indicating that mitochondrial dysfunction occurred in the absence of caspase activation.

Interestingly, although all three compounds increased the generation of reactive oxygen species and decreased phosphorylation of extracellular signal-regulated kinase, only cis-guggulsterone induced a rapid depletion of reduced glutathione levels and oxidation of the mitochondrial phospholipid cardiolipin.

Guggulsterones and 16-dehydroprogesterone hence exert anti-leukemic effects via the induction of apoptosis and differentiation and, more importantly, identifies the pregnadienedione structure as a potential chemotherapeutic scaffold (Samudio et al., 2005).

Multi-drug Resistance

Natural phytosterols, such as beta-sitosterol, campesterol, stigmasterol, fucosterol, and z-guggulsterone, are found in foods, herbs, and dietary supplements. The effects of dietary plant sterols on human drug efflux transporters P-glycoprotein (P-gp, ABCB1) and multi-drug resistance protein 1 (MRP1, ABCC1) were investigated using P-gp-overexpressing human carcinoma KB-C2 cells and human MRP1 gene-transfected KB/MRP cells.

The accumulation of daunorubicin or rhodamine 123, fluorescent substrates of P-gp, increased in the presence of guggulsterone in KB-C2 cells. The efflux of rhodamine 123 from KB-C2 cells was inhibited by guggulsterone. Guggulsterone also increased the accumulation of calcein, a fluorescent substrate of MRP1, in KB/MRP cells. The ATPase activities of P-gp and MRP1 were stimulated by guggulsterone.

These results suggest that guggulsterone, a natural dietary hypolipidemic agent, have dual inhibitory effects on P-gp and MRP1 and the potencies to cause food-drug interactions.

References

Nabekura T, Yamaki T, Ueno K, Kitagawa S. (2008). Effects of plant sterols on human Multi-drug transporters ABCB1 and ABCC1. Biochemical and Biophysical Research Communications, 369(2), 363-368. doi: 10.1016/j.bbrc.2008.02.026.


Samudio I, Konopleva M, Safe S, et al. (2005). Guggulsterones induce apoptosis and differentiation in acute myeloid leukemia: identification of isomer-specific antileukemic activities of the pregnadienedione structure. Mol Cancer Ther, 4:1982. doi: 10.1158/1535-7163.MCT-05-0247.

Guben Xiaoliu Extract

Cancer: Colorectal., lung

Action: Improves cellular immune function, relieves myelosuppression

Colorectal

Seventy eight advanced colorectal cancer patients were randomly assigned to treatment group (38 patients) and control group (40 patients). Oxaliplatin 85 mg/m^2 IV infusion for 2 hours, dl. CF 200 mg/m^2 IV infusion for 2 hours followed by 5-FU 400 mg/m^2 iv infusion for 22 hours, d1-2, were administered. Every two weeks was a cycle. The control group was treated by FOLFOX4 regimen, while Guben Xiaoliu capsule was added in the treatment group. Patients were evaluated after 4 cycles. Clinical beneficial rate of treatment and contral group were 76.3% and 57.5% respectively (P<0.05).

Guben Xiaoliu capsule decreased blood hypercoagulability, improved cellular immune function of patients, relieved myelosuppression of chemotherapeutic agents and improved quality of life of patients. FOLFOX4 regimen combined with Guben Xiaoliu capsule had better effect in the treatment of advance colorectal cancer patients (Hu et al., 2007).

NSCLC

One hundred and ninety eight NSCLC in-patients were divided into the integrative treated group (Group A, 54 patients treated with chemotherapy (CT) plus GXC), the TCM treated group (Group B, 96 patients treated with GXC alone) and the chemotherapeutic group (Group C, 48 patients treated with CT alone). Randomized controlled observation was applied to Group A and Group C. The clinical effect, quality of life (QOL), adverse reaction and survival period in the three groups were observed. The immediate effective rate (CR+PR) in Groups A, B, and C was 16.7%, 3.1% and 8.3%, respectively; in Group A, it was better than in the other two groups (P<0 05).

The improvement of clinical symptoms and QOL in Groups A and B were superior to those in Group C (P<0 05). The median survival rate in the three groups was 12, 15 and 9 months, respectively, the 1-, 2-, and 3-year survival rate in Group A being 57.4%, 11.1% and 3.7%, respectively, in Group B, 67.7%, 9.4% and 3.1%, and in Group C, 39.6%, 4.2% and 0, respectively. Comparison between the three groups showed that the survival rates in the former two were higher than those in Group C (P<0 05).

Moreover, the incidence rate and degree of CT toxicity were milder in Group A than in Group C (P<0 05). GXC has definite effect in treating NSCLC; it could raise the QOL and prolong the survival period of patients, and also reduce the toxicity and enhance the efficacy of CT (Wang et al., 2004).

Lewis lung carcinoma

In vivo animal experiment was used to investigate the growth of mice tumors. Immunological (SP) and quantitative pathologic image analysis were used to investigate the microvessel density (MVD) and expression of vascular endothelial growth factor (VEGF) in tumor tissue. The inhibitory rates on mouse tumor of GC group, chemotherapy group and GC chemotherapy group were 40.58%, 52.69%, 61.09% respectively.

The inhibitory rates are significantly higher than for the control, while MVD and expression of VEGF of GC group and GC chemotherapy group and MVD of chemotherapy group decreased significantly. GC could inhibit the growth and angiogenesis of Lewis lung carcinoma of mice (Yang et al., 2004).

Formula

Sclerotium Cordyceps Chinensis (dong chong xia cao), Fructificatio Ganodermatus (ling zhi), Radix Panacis Quinque Folii (xi yang shen), Herba Epimedii (yin yang huo), Bulbus Fritillariae Thunbergii (zhe bei mu), Semen Coicis Lachryma-Jobi (yi yi ren), Hirudo seu Whitmaniae (shui zhi), Buthus Martensi (quan xie), Herba Solanum Nigrum (long kui), Rhizoma Curcumae Ezhu (e zhu), Rhizoma Smilacis Glabrae (tu fu ling), Scolopendra Subspinipes (wu gong)

References

Hu F, Zhang Q, Wang X, Yang G, Zhao W. (2007). Clinical Study of Guben Xiaoliu Capsule Combined with FOLFOX4 Regimen in Treating Advanced Colorect Cancer. Zhong Guo Zhong Yi Yao Xin Xi Za Zhi, 14(7): 13-14.


Wang X, Xin H, Yang Z, Zhao W, Yang G, Liu J, Tang W, Zhang Q, Han D, Yu R. (2004). Clinical Study on Treatment of Advanced Stage Non Small Cell Lung Cancer. Zhong Guo Zhong Xi Yi Jie He Za Zhi, 24(11): 986-988.


Yang GW, Wang XM, Wang Z, Peng RY, Gao YB, Wang XM. (2004). Inhibitory Effect and Antiangiogenesis of Gubenxiaoliu Capsule on Lewis Lung Carcinoma of Mouse. China Journal of Experimental Traditional Medical Formulae, 10(5):50-52.

Glycyrrhiza Uralensis: Glycyrrhizin, Isoliquiritigenin

Cancer:
Cervical., breast, stomach, liver, hepatoma, prostate

Action: Induces apoptosis

The active components of Glycyrrhiza uralensis include the total flavones extracted from Chinese licorice, Glycyrrhiza uralensis Fisch.

Stomach Cancer, Hepatoma, Breast Cancer, Cervical Cancer

The anti-proliferation effect of glycyrrhizhin and total flavones extracted from Chinese licorice, Glycyrrhiza uralensis Fisch, on four kinds of human cancer cells (cervix tumor cell; Hela, breast tumor cell; Bcap-37, stomach tumor cell; MGC-803 and hepatoma cell; Bel-7404) were studied. MTT showed that the anti-proliferation effect of glycyrrhizin was concentration-dependent; higher concentration of glycyrrhizin (1000µg/ml) had obvious anti-tumor effect; within certain concentrations of (200~1000µg/ml), inhibitory effect of total flavones was also concentration dependent; the lower concentration (200µg/ml) was of the highest inhibitory effect: its inhibiting rates on Bcap-37, Hela, Bel-7404, MGC-803 were 79.55%, 79.98%, 67.91% and 37.86% respectively.

Both glycyrrhizin and total flavones have stronger apoptosis-inducing effects on the four kinds of tumor cells (Ma et al., 2008).

Prostate Cancer

Kanazawa et al. (2003) investigated the anti-tumor effect of isoliquiritigenin on prostate cancer in vitro. DU145 and LNCaP prostate cancer cell lines were used as targets. The effects of isoliquiritigenin were examined on cell proliferation, cell-cycle regulation and cell-cycle-regulating gene expression. Further, they investigated the effects of isoliquiritigenin on the GADD153 mRNA and protein expression, and promoter activity. Isoliquiritigenin significantly inhibited the proliferation of prostate cancer cell lines in a dose-dependent and time-dependent manner. These findings suggest that isoliquiritigenin is a candidate agent for the treatment of prostate cancer and GADD153 may play an important role in isoliquiritigenin-induced cell-cycle arrest and cell growth inhibition.

References

Kanazawa M, Satomi Y, Mizutani Y, et al. (2003). Isoliquiritigenin inhibits the growth of prostate cancer. Eur Urol. 43(5):580-6.


Ma M, Zhou X-l, Hu Y-l, et al. (2008). Lishizhen Medicine and Materia Medica Research. doi: CNKI:SUN:SZGY.0.2008-01-006

Glyceolins

Cancer: Prostate, breast, ovarian

Action: Anti-estrogenic

Glyceollins are soy-derived phytoalexins isolated from activated soy ( Glycine max [(L.) Merr.] that have been proposed to be candidates for cancer-preventive compounds.

Prostate cancer

It has been found that the glyceollins inhibited prostate cancer cell LNCaP growth similar to that of the soy isoflavone genistein. The growth-inhibitory effects of the glyceollins appeared to be due to an inhibition of G1/S progression and correlated with an up-regulation of cyclin-dependent kinase inhibitor 1 A and B mRNA and protein levels. By contrast, genistein only up-regulates cyclin-dependent kinase inhibitor 1A.

In addition, glyceollin treatments led to down-regulated mRNA levels for androgen responsive genes. In contrast to genistein, this effect of glyceollins on androgen responsive genes appeared to be mediated through modulation of an estrogen- but not androgen-mediated pathway.

Hence, the glyceollins exerted multiple effects on LNCaP cells that may be considered cancer-preventive and the mechanisms of action appeared to be different from other soy-derived phytochemicals (Payton-Stewart et al., 2009).

Anti-estrogenic Effects; Breast Cancer, Ovarian Cancer

The phytoalexin compounds glyceollins I, II, and III have been identified to exhibit marked anti-estrogenic effects on estrogen receptor function and estrogen-dependent tumor growth in vivo. The interactions among the induced soy phytoalexins glyceollins I, II, and III on the growth of estrogen-dependent MCF-7 breast cancer and BG-1 ovarian cancer cells were studied. Four treatment groups for each cell line were used: vehicle control, 20 mg/kg/mouse/d glyceollin mixture injection, 0.72 mg estradiol (E2) implant, and E2 implant + 20 mg/kg/mouse/d glyceollin injection.

Treatment with glyceollin suppressed E2-stimulated tumor growth of MCF-7 cells (-53.4%) and BG-1 cells (-73.1%) in ovariectomized athymic mice. These tumor-inhibiting effects corresponded with significantly lower E2-induced progesterone receptor expression in the tumors. In contrast to tamoxifen, the glyceollins had no estrogen-agonist effects on uterine morphology and partially antagonized the uterotropic effects of estrogen. These findings identify glyceollins as anti-estrogenic agents that may be useful in the prevention or treatment of breast and ovarian carcinoma (Salvo et al., 2006).

Anti-estrogenic Effects

The soybean plant under stress produces a mixture of glyceollins I, II, and III that bind to the estrogen receptor (ER) and inhibit estrogen-induced tumor progression. In further in vitro studies, the glyceollin mixture exhibits potential anti-estrogenic, therapeutic activity preventing estrogen-stimulated tumorigenesis and displaying a differential pattern of gene expression from tamoxifen.

Glyceollin I was identified as the active anti-estrogenic component of the mixture. Ligand-receptor modeling (docking) of the isomers within the ERα ligand binding cavity demonstrated a unique type II anti-estrogenic confirmation adopted by glyceollin I, but not isomers II and III. Glyceollin I treatment in 17β- estradiol-stimulated MCF-7 breast cancer cells and BG-1 ovarian cancer cells resulted in a novel inhibition of ER-mediated gene expression and cell proliferation/ survival.

Glyceollin I may represent an important component of a phytoalexin-enriched food (activated) diet in terms of chemoprevention as well as a novel therapeutic (Tilghman et al., 2010).

References

Payton-Stewart F, Schoene NW, Kim YS, et al. (2009). Molecular effects of soy phytoalexin glyceollins in human prostate cancer cells LNCaP. Molecular Carcinogenesis, 48(9):862–71. doi: 10.1002/mc.20532.


Salvo VA, BouŽ SM, Fonseca JP, et al. (2006). Antiestrogenic glyceollins suppress human breast and ovarian carcinoma tumorigenesis. Clin Cancer Res, 12(23):7159-64. doi: 10.1158/1078-0432.CCR-06-1426.


Tilghman SL, BouŽ SM, Burow ME. (2010). Glyceollins, a novel class of antiestrogenic phytoalexins. Molecular and Cellular Pharmacology, 2(4):155-60. doi: 10.4255/mcpharmacol.10.21

Glabridin

Cancer: Breast

Action: Inhibits metastasis, inhibits angiogenesis

Glabridin is a novel phytoestrogen isolated from licorice extract (Glycyrrhiza glabra (L.))

Breast Cancer Growth; Estrogen agonist

Glabridin and its derivatives bind to the human ER and have been found to act as an estrogen agonist in the induction of an estrogen response marker, such as CK activity, in vivo, to induce uterus wet weight, and to stimulate human breast cancer cell growth. There is an increasing demand for natural compounds that improve women's health by mimicking the critical benefits of estrogen to the bones and the cardiovascular system but avoiding its deleterious effects on the breast and uterus.

The estrogenic properties of glabridin, the major isoflavan in licorice root, were tested in view of the resemblance of its structure and lipophilicity to those of estradiol. The results indicate that glabridin is a phytoestrogen, binding to the human estrogen receptor and stimulating creatine kinase activity in rat uterus, epiphyseal cartilage, diaphyseal bone, aorta, and left ventricle of the heart. This indicates that isoflavans have estrogen-like activities. Glabridin and its derivatives exhibited varying degrees of estrogen receptor agonism in different tests and demonstrated growth-inhibitory actions on breast cancer cells (Tamir et al., 2000).

Inhibits Metastasis, Inhibits Angiogenesis

Glabridin exhibited effective inhibition of cell metastasis by decreasing cancer cell migration and invasion of metastatic MDA-MB-231 breast cancer cells. In addition, glabridin also blocked human umbilical vein endothelial cells (HUVEC) migration and decreased MDA-MB-231-mediated angiogenesis. Further investigation revealed that the inhibition of cancer angiogenesis by glabridin was also evident in a nude mice model. Blockade of MDA-MB-231 cells and HUVEC migration was associated with an increase of αγβ3 integrin proteosome degradation. Glabridin also decreased the active forms of FAK and Src, and enhanced levels of inactivated phosphorylated Src (Tyr 416), decreasing the interaction of FAK and Src.

Inhibition of the FAK/Src complex by glabridin also blocked AKT and ERK1/2 activation, resulting in reduced activation of RhoA as well as myosin light chain phosphorylation. This study demonstrates that glabridin may be a novel anti-cancer agent for the treatment of breast cancer in three different ways: inhibition of migration, invasion and angiogenesis (Hsu et al., 2011).

References

Hsu YL, Wu LY, Hou MF, et al. (2011). Glabridin, an isoflavan from licorice root, inhibits migration, invasion and angiogenesis of MDA-MB-231 human breast adenocarcinoma cells by inhibiting focal adhesion kinase/Rho signaling pathway. Molecular Nutrition & Food Research, 55(2):318–27. doi: 10.1002/mnfr.201000148.


Tamir S, Eizenberg M, Somjen D, et al. (2000). Estrogenic and Anti-proliferative Properties of Glabridin from Licorice in Human Breast Cancer Cells. Cancer Res, 60:5704

Germacrone

Cancer: Breast, stomach

Action: Cell-cycle arrest

Traditional medicinal herbs are an untapped source of potential pharmaceutical compounds. Germacrone is a natural product isolated from Rhizoma curcuma longa (L.).

Breast Cancer

Germacrone has been investigated for its inhibition on the proliferation of breast cancer cell lines. Germacrone treatment significantly inhibited cell proliferation, increased lactate dehydrogenase (LDH) release, and induced mitochondrial membrane potential (ΔΨ m) depolarization in both MCF-7 and MDA-MB-231 cells in a dose-dependent manner. Germacrone induced MDA-MB-231 and MCF-7 cell-cycle arrest at the G0/G1 and G2/M phases respectively and induced MDA-MB-231 cell apoptosis.

In addition, germacrone treatment induced caspase-3, 7, 9, PARP cleavage. It was therefore concluded that germacrone inhibited the proliferation of breast cancer cell lines by inducing cell-cycle arrest and apoptosis through mitochondria-mediated caspase pathway. These results might provide some molecular basis for the anti-tumor activity of Rhizoma curcuma (Zhong et al., 2011).

Stomach Cancer

Germacrone, contained in zedoary oil from Rhizoma curcuma, significantly decreased the cell viability of AGS cells (P < 0.01) and MGC 803 cells (P < 0.01), and the inhibitory effects were attenuated by elevated concentrations of FBS. At high concentrations (>=90 mug/mL), zedoary oil killed GES-1 cells. At low concentrations (<=60 mug/mL), zedoary oil was less inhibitory toward gastric cancer cell lines. In AGS cells, zedoary oil inhibited cell proliferation in a dose- and time-dependent manner, with decreased PCNA protein expression in the zedoary oil-treated cells, and arrested the cell-cycle at S, G2/M and G0/G1 stages after treatment for 6–48 hours. At concentrations of 30, 60 and 90 mug/mL, which resulted in significant inhibition of proliferation and cell-cycle arrest, zedoary oil induced cell apoptosis.

Zedoary oil up-regulated the ratio of Bax/Bcl-2 protein expression (P < 0.01). Zedoary oil which contains germacrone was hence found to inhibit AGS cell proliferation through cell-cycle arrest and cell apoptosis promotion, which are related to Bax/Bcl-2 protein expression.

References

Shi H, Tan B, Ji G, et al. (2013). Zedoary oil (Ezhu You) inhibits proliferation of AGS cells. Chin Med, 8(1):13.


Zhong Z, Chen X, Tan W, et al. (2011). Germacrone inhibits the proliferation of breast cancer cell lines by inducing cell-cycle arrest and promoting apoptosis. Eur J Pharmacol, 667(1-3):50-55. doi:10.1016/j.ejphar.2011.03.041.

Geraniin

Cancer: Melanoma, T cell leukemia, cervical

Action: Causes cell-cycle arrest

Melanoma

Geraniin, a form of tannin separated from Geranium genus (including Geranium niveum (S. Watson)), causes cell death through induction of apoptosis. Geraniin triggered cell death by caspase-3-mediated cleavage of FAK and was associated with the up-regulation of Fas ligand expression, the activation of caspase-8, the cleavage of Bid, and the induction of cytochrome c release from mitochondria to the cytosol in human melanoma cells (Lee et al., 2008).

Leukemia, Cervical Cancer

Different concentrations of geraniin, the level of expression of the client proteins c-Raf, pAkt, and EGFR, was strongly down-regulated. Geraniin was able to inhibit in vitro the Hsp90α ATPase activity in a dose-dependent manner, with an inhibitory efficiency comparable to that measured for 17-AAG. In addition, this compound compromised the chaperone activity of Hsp90α, monitored by the citrate synthase thermal induced aggregation assay. Geraniin decreased the viability of HeLa and Jurkat cell lines and caused an arrest in G2/M phase. These results, along with the finding that geraniin did not exert any appreciable cytotoxicity on normal cells, encourage further studies on this compound as a promising chemical scaffold for the design of new Hsp90 inhibitors (Vassallo et al., 2013).

References

Lee JC, Tsai CY, Kao JY, et al. (2008). Geraniin-mediated apoptosis by cleavage of focal adhesion kinase through up-regulation of Fas ligand expression in human melanoma cells. Mol Nutr Food Res, 52(6):655-63.


Vassallo A, Vaccaro MC, De Tommasi N, Dal Piaz F, Leone A. (2013). Identification of the plant compound geraniin as a novel hsp90 inhibitor. PLoS One, 8(9):e74266. doi: 10.1371/journal.pone.0074266.

Gentianaceae

Cancer: Prostate, breast, lung, pancreatic

Action: Causes cell-cycle arrest

Gentianaceae is a naturally occurring alkaloid isolated from Sophora flavescens (Aiton).

Prostate Cancer; AR-

Gentianaceae has shown anti-proliferative properties in a number of types of cancer, including breast, gastric, lung and pancreatic tumors. Gentianaceae was also found to promote apoptosis and inhibit invasion of cancer cells.

The anti-tumor effects of gentianaceae were evaluated on androgen-independent PC-3 prostate cancer cells. The effects of gentianaceae on cell-cycle progression and apoptosis of PC-3 cells were tested. Gentianaceae-treated PC-3 cells underwent G0/G1 cell-cycle arrest. There was a significant reduction in the number of S phase and G2/M phase cells in the treated group when compared to untreated cells.

There was also an increase in the number of necrotic cells in the gentianaceae-treated group when compared to untreated cells. Gentianaceae treatment resulted in increased levels of caspase-3 and Bax and decreased levels of Bcl-2. The data suggest that gentianaceae inhibits the proliferation of androgen-independent prostate cancer cells by causing G0/G1 cell-cycle arrest and promoting apoptosis. Gentianaceae-induced apoptosis was mediated by down-regulation of Bcl-2/Bax ratios and up-regulation of caspase-3 levels (Zhang et al., 2012).

Reference

Zhang P, Wang Z, Chong T, Ji Z. (2012). Matrine inhibits proliferation and induces apoptosis of the androgen “American Typewriter”; “American Typewriter”;‑ independent prostate cancer cell line PC-3. Mol Med Report, 5(3):783-7. doi: 10.3892/mmr.2011.701.

Geniposide –Penta-acetyl Geniposide (Ac)5GP

Cancers:
Glioma, melanoma, liver, hepatocarcinogenesis, hepatoma, prostate, cervical

Action: Cytostatic, induces apoptosis

Gardenia, the fruit of Gardenia jasminoides Ellis, has been widely used to treat liver and gall bladder disorders in Chinese medicine. It has been shown recently that geniposide, the main ingredient of Gardenia fructus , exhibits anti-tumor effect.

Hepatocarcinogenesis, Glioma

It has been demonstrated that (Ac)5GP plays more potent roles than geniposide in chemoprevention. (Ac)5GP decreased DNA damage and hepatocarcinogenesis, induced by aflatoxin B1 (AFB1), by activating the phase II enzymes glutathione S-transferase (GST) and GSH peroxidase (GSH-Px). It reduced the growth and development of inoculated C6 glioma cells, especially in pre-treated rats. In addition to the preventive effect, (Ac)5GP exerts its actions on apoptosis and growth arrest.

Treatment of (Ac)5GP caused DNA fragmentation of glioma cells. (Ac)5GP induced sub- G1 peak through the activation of apoptotic cascades PKCdelta/JNK/Fas/caspase8 and caspase 3. It arrested the cell-cycle at G0/ G1 by inducing the expression of p21, thus suppressing the cyclin D1/cdk4 complex formation and the phosphorylation of E2F.

Data from in vivo experiments indicated that (Ac)5GP is not harmful to the liver, heart and kidney. (Ac)5GP is strongly suggested to be an anti-tumor agent for development in the future (Peng, Huang, & Wang, 2005).

Induces Apoptosis

Previous studies have demonstrated the apoptotic cascades protein kinase C (PKC) delta/c-Jun NH2-terminal kinase (JNK)/Fas/caspases induced by penta-acetyl geniposide [(Ac)5GP]. However, the upstream signals mediating PKCdelta activation have not yet been clarified. Ceramide, mainly generated from the degradation of sphingomyelin, was hypothesized upstream above PKCdelta in (Ac)5GP-transduced apoptosis.

After investigation, (Ac)5GP was shown to activate neutral sphingomyelinase (N-SMase) immediately, with its maximum at 15 min. The NGF and p75 enhanced by (Ac)5GP was inhibited when combined with GW4869, the N-SMase inhibitor, indicating NGF/p75 as the downstream signals of N-SMase/ceramide. To evaluate whether N-SMase is involved in (Ac)5GP-transduced apoptotic pathway, cells were treated with (Ac)5GP, alone or combined with GW4869. It was demonstrated that N-SMase inhibition blocked FasL expression and caspase 3 activation. Similarly, p75 antagonist peptide attenuated the FasL/caspase 3 expression. It indicated that N-SMase activation is pivotal in (Ac)5GP-mediated apoptosis.

SMase and NGF/p75 are suggested to mediate upstream above PKCdelta, thus transducing FasL/caspase cascades in (Ac)5GP-induced apoptosis (Peng, Huang, Hsu, & Wang, 2006).

Glioma

Penta-acetyl geniposide [(Ac)(5)GP], an acetylated geniposide product from Gardenia fructus, has been known to have hepato-protective properties and recent studies have revealed its anti-proliferative and apoptotic effect on C6 glioma cells. The anti-metastastic effect of (Ac)(5)GP in the rat neuroblastoma line C6 glioma cells were investigated.

Further (Ac)(5)GP also exerted an inhibitory effect on phosphoinositide 3-kinase (PI3K) protein expression, phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and inhibition of activation of transcription factor nuclear factor kappa B (NF-kappaB), c-Fos, c-Jun.

Findings suggest (Ac)(5)GP is highly likely to be an inhibiting cancer migration agent to be further developed in the future (Huang et al., 2009).

Melanoma

A new iridoid glycoside, 10-O-(4'-O-methylsuccinoyl) geniposide, and two new pyronane glycosides, jasminosides Q and R, along with nine known iridoid glycosides, and two known pyronane glycosides, were isolated from a MeOH extract of Gardeniae Fructus, the dried ripe fruit of Gardenia jasminoides (Rubiaceae).

The structures of new compounds were elucidated on the basis of extensive spectroscopic analyzes and comparison with literature. Upon evaluation of these compounds on the melanogenesis in B16 melanoma cells induced with α-melanocyte-stimulating hormone (α-MSH), three compounds, i.e., 6-O-p-coumaroylgeniposide (3), 7, and 6'-O-sinapoyljasminoside (12), exhibited inhibitory effects with 21.6-41.0 and 37.5-47.7% reduction of melanin content at 30 and 50 µM, respectively, with almost no toxicity to the cells (83.7-106.1% of cell viability at 50 µM) (Akisha et al., 2012).

Hepatoma, Prostate Cancer, Cervical Cancer

Genipin is a metabolite of geniposide isolated from an extract of Gardenia fructus. Some observations suggested that genipin could induce cell apoptosis in hepatoma cells and PC3 human prostate cancer cells. Genipin could remarkably induce cytotoxicity in HeLa cells and inhibit its proliferation. Induction of the apoptosis by genipin was confirmed by analysis of DNA fragmentation and induction of sub-G(1) peak through flow cytometry.

The results also showed that genipin-treated HeLa cells cycle was arrested at G(1) phase. Western blot analysis revealed that the phosphorylated c-Jun NH(2)-terminal kinase (JNK) protein, phospho-Jun protein, p53 protein and bax protein significantly increased in a dose-dependent manner after treatment of genipin for 24 hours; the activation of JNK may result in the increase of the p53 protein level; the increase of the p53 protein led to the accumulation of bax protein; and bax protein further induced cell apoptotic death eventually (Cao et al., 2010).

References

Akihisa T, Watanabe K, Yamamoto A, et al. (2012). Melanogenesis inhibitory activity of monoterpene glycosides from Gardeniae Fructus. Chemistry & Biodiversity, 9(8), 1490-9. doi: 10.1002/cbdv.201200030.


Cao H, Feng Q, Xu W, et al. (2010). Genipin induced apoptosis associated with activation of the c-Jun NH2-terminal kinase and p53 protein in HeLa cells. Biol Pharm Bull, 33(8):1343-8.


Huang HP, Shih YW, Wu CH, et al. (2009). Inhibitory effect of penta-acetyl geniposide on C6 glioma cells metastasis by inhibiting matrix metalloproteinase-2 expression involved in both the PI3K and ERK signaling pathways. Chemico-biological Interactions, 181(1), 8-14. doi: 10.1016/j.cbi.2009.05.009.


Peng CH, Huang CN, Hsu SP, Wang CJ. (2006). Penta-acetyl geniposide induce apoptosis in C6 glioma cells by modulating the activation of neutral sphingomyelinase-induced p75 nerve growth factor receptor and protein kinase Cdelta pathway. Molecular Pharmacology, 70(3), 997-1004.


Peng CH, Huang CN, Wang CJ. (2005). The anti-tumor effect and mechanisms of action of penta-acetyl geniposide. Current Cancer Drug Targets, 5(4), 299-305.

Eugenol

Cancer:
Melanoma, osteosarcoma, leukemia, gastric, colon, liver, oral., lung

Action: Radio-protective

Eugenol is a natural compound available in honey and various plants extracts; in particular, cloves (Syzygium aromaticum (L.) Merrill & Perry).

Melanoma, Skin Tumors, Osteosarcoma, Leukemia, Gastric Cancer

Eugenol (4-allyl-2-methoxyphenol), a phenolic phytochemicals, is the active component of Syzigium aromaticum (cloves). Aromatic plants like nutmeg, basil, cinnamon and bay leaves also contain eugenol. Eugenol has a wide range of applications like perfumeries, flavorings, essential oils and in medicine as a local antiseptic and anesthetic. Increasing volumes of literature show eugenol possesses anti-oxidant, anti-mutagenic, anti-genotoxic, anti-inflammatory and anti-cancer properties.

The molecular mechanism of eugenol-induced apoptosis in melanoma, skin tumors, osteosarcoma, leukemia, gastric and mast cells has been well documented and highlights the anti-proliferative activity and molecular mechanism of eugenol-induced apoptosis against the cancer cells and animal model (Jaganathan et al., 2012).

Colon Cancer

Since most of the drugs used in cancer are apoptosis-inducers, the apoptotic effect and anti-cancer mechanism of eugenol were investigated against colon cancer cells. MTT assay signified the anti-proliferative nature of eugenol against the tested colon cancer cells. PI staining indicated increasing accumulation of cells at sub-G1-phase. Eugenol treatment resulted in reduction of intracellular non-protein thiols and increase in the earlier lipid layer break. Further events like dissipation of MMP and generation of ROS (reactive oxygen species) were accompanied in the eugenol-induced apoptosis. Augmented ROS generation resulted in the DNA fragmentation of treated cells as shown by DNA fragmentation and TUNEL assay. Further activation of PARP (polyadenosine diphosphate-ribose polymerase), p53 and caspase-3 were observed in Western blot analyzes.

These results demonstrate the molecular mechanism of eugenol-induced apoptosis in human colon cancer cells. This research will further enhance eugenol as a potential chemo-preventive agent against colon cancer (Jaganathan et al., 2011).

Radio-protective, Skin Cancer, Liver Cancer, Oral Cancer, Lung Cancer

Ocimum sanctum L. or Ocimum tenuiflorum L , commonly known as Holy Basil in English or Tulsi in the various Indian languages, is an important medicinal plant in the various traditional and folk systems of medicine in Southeast Asia, and another plant from which eugenol is extracted. Scientific studies have shown it to possess anti-inflammatory, analgesic, anti-pyretic, anti-diabetic, hepato-protective, hypolipidemic, anti-stress, and immunomodulatory activities. Preclinical studies have also shown that Ocimum and some of its phytochemicals including eugenol prevented chemical-induced skin, liver, oral., and lung cancers and to mediate these effects by increasing the anti-oxidant activity, altering the gene expressions, inducing apoptosis, and inhibiting angiogenesis and metastasis.

The aqueous extract of Ocimum and its flavanoids, orintin and vicenin, are shown to protect mice against γ-radiation-induced sickness and mortality and to selectively protect the normal tissues against the tumoricidal effects of radiation. This action is related to the important phytochemicals it contains like eugenol, which are also shown to prevent radiation-induced DNA damage.

References

Baliga MS, Jimmy R, Thilakchan KR, et al. (2013). Ocimum sanctum L (Holy Basil or Tulsi) and its phytochemicals in the prevention and treatment of cancer. Nutr Cancer, 65(1):26-35. doi: 10.1080/01635581.2013.785010.


Jaganathan SK, Mazumdar A, Mondhe D, Mandal M. (2011). Apoptotic effect of eugenol in human colon cancer cell lines. Cell Biol Int, 35(6):607-15. doi: 10.1042/CBI20100118.


Jaganathan SK, Supriyanto E. (2012). Anti-proliferative and Molecular Mechanism of Eugenol-Induced Apoptosis in Cancer Cells. Molecules, 17(6):6290-6304. doi:10.3390/molecules17066290.

EGCG, ECG, CG, EC

Cancer: Breast, pancreatic, lung, colorectal

Action: Chemo-preventive effects, metastasis

(-)-Epigallocatechin gallate (EGCG) is isolated from Camellia sinensis [(L.) Kuntze].

Epidemiological evidence suggests tea (Camellia sinensis L.) has chemo-preventive effects against various tumors. (-)-Epigallocatechin gallate (EGCG), a catechin polyphenol compound, represents the main ingredient of green tea extract and is chemo-preventive and an anti-oxidant. EGCG shows growth inhibition of various cancer cell lines, such as lung, mammary, and stomach.

Breast Cancer, Colorectal Cancer

Although EGCG has been shown to be growth-inhibitory in a number of tumor cell lines, it is not clear whether the effect is cancer-specific. The effect of EGCG on the growth of SV40 virally transformed WI38 human fibroblasts (WI38VA) was compared with that of normal WI38 cells. The IC50 value of EGCG was estimated to be 120 and 10 microM for WI38 and WI38VA cells, respectively. Similar differential growth inhibition was also observed between a human colorectal cancer cell line (Caco-2), a breast cancer cell line (Hs578T) and their respective normal counterparts.

EGCG at a concentration range of 40-200 microM induced a significant amount of apoptosis in WI38VA cultures, but not in WI38 cultures, as determined by terminal deoxynucleotidyl transferase assay. It is possible that differential modulation of certain genes, such as c-fos and c-myc, may cause differential effects of EGCG on the growth and death of cancer cells (Chen et al., 1998).

Breast Cancer

Green tea contains many polyphenols, including epigallocatechin-3 gallate (EGCG), which possess anti-oxidant qualities. Reduction of chemically-induced mammary gland carcinogenesis by green tea in a carcinogen-induced rat model has been suggested previously, but the results reported were not statistically significant. Green tea significantly increased mean latency to the first tumor, and reduced tumor burden and number of invasive tumors per tumor-bearing animal; however, it did not affect tumor number in female rats.

Furthermore, we show that proliferation and/or viability of cultured Hs578T and MDA-MB-231 estrogen receptor-negative breast cancer cell lines was reduced by EGCG treatment. Similar negative effects on proliferation were observed with the DMBA-transformed D3-1 cell line. Growth inhibition of Hs578T cells correlated with induction of p27Kip1 cyclin-dependent kinase inhibitor (CKI) expression.

Thus, green tea had significant chemo-preventive effects on carcinogen-induced mammary tumorigenesis in female S-D rats. In culture, inhibition of human breast cancer cell proliferation by EGCG was mediated in part via induction of the p27Kip1 (Kavanagh et al., 2001).

Pancreatic Cancer

The in vitro anti-tumoral properties of EGCG were investigated in human PDAC (pancreatic ductal adenocarcinoma) cells PancTu-I, Panc1, Panc89 and BxPC3 in comparison with the effects of two minor components of green tea catechins, catechin gallate (CG) and epicatechin gallate (ECG). It was found that all three catechins inhibited proliferation of PDAC cells in a dose- and time-dependent manner.

Interestingly, CG and ECG exerted much stronger anti-proliferative effects than EGCG. Importantly, catechins, in particular ECG, inhibited TNFα-induced activation of NF-κB and consequently secretion of pro-inflammatory and invasion promoting proteins like IL-8 and uPA.

Overall, these data show that green tea catechins ECG and CG exhibit potent and much stronger anti-proliferative and anti-inflammatory activities on PDAC cells than the most studied catechin EGCG (KŸrbitz et al., 2011).

Okabe et al. (1997) assessed the ability of EGCG to inhibit HGF signaling in the immortalized, nontumorigenic breast cell line, MCF10A, and the invasive breast carcinoma cell line, MDA-MB-231. The ability of alternative green tea catechins to inhibit HGF-induced signaling and motility was investigated. (-)-Epicatechin-3-gallate (ECG) functioned similarly to EGCG by completely blocking HGF-induced signaling as low as 0.6 muM and motility at 5 muM in MCF10A cells; whereas, (-)-epicatechin (EC) was unable to inhibit HGF-induced events at any concentration tested. (-)-Epigallocatechin (EGC), however, completely repressed HGF-induced AKT and ERK phosphorylation at concentrations of 10 and 20 muM, but was incapable of blocking Met activation. Despite these observations, EGC did inhibit HGF-induced motility in MCF10A cells at 10 muM.

Metastsis Inhibition

These observations suggest that the R1 galloyl and the R2 hydroxyl groups are important in mediating the green tea catechins' inhibitory effect towards HGF/Met signaling. These combined in vitro studies reveal the possible benefits of green tea polyphenols as cancer therapeutic agents to inhibit Met signaling and potentially block invasive cancer growth (Bigelow et al., 2006).

Colorectal Cancer

Panaxadiol (PD) is a purified sapogenin of ginseng saponins, which exhibits anti-cancer activity. Epigallocatechin gallate (EGCG), a major catechin in green tea, is a strong botanical anti-oxidant. Effects of selected compounds on HCT-116 and SW-480 human colorectal cancer cells were evaluated by a modified trichrome stain cell proliferation analysis. Cell-cycle distribution and apoptotic effects were analyzed by flow cytometry after staining with PI/RNase or annexin V/PI. Cell growth was suppressed after treatment with PD (10 and 20  µm) for 48 h. When PD (10 and 20  µm) was combined with EGCG (10, 20, and 30  µm), significantly enhanced anti-proliferative effects were observed in both cell lines.

Combining 20  µm of PD with 20 and 30   µm of EGCG significantly decreased S-phase fractions of cells. In the apoptotic assay, the combination of PD and EGCG significantly increased the percentage of apoptotic cells compared with PD alone (p  < 0.01).

Data from this study suggested that apoptosis might play an important role in the EGCG-enhanced anti-proliferative effects of PD on human colorectal cancer cells (Du et al., 2013).

Action: Anti-inflammatory, antioxidant

Green tea catechins, especially epigallocatechin-3-gallate (EGCG), have been associated with cancer prevention and treatment. This has resulted in an increased number of studies evaluating the effects derived from the use of this compound in combination with chemo/radiotherapy. Most of the studies on this subject up to date are preclinical. Relevance of the findings, impact factor, and date of publication were critical parameters for the studies to be included in the review.

Additive and synergistic effects of EGCG when combined with conventional cancer therapies have been proposed, and its anti-inflammatory and antioxidant activities have been related to amelioration of cancer therapy side effects. However, antagonistic interactions with certain anticancer drugs might limit its clinical use.

The use of EGCG could enhance the effect of conventional cancer therapies through additive or synergistic effects as well as through amelioration of deleterious side effects. Further research, especially at the clinical level, is needed to ascertain the potential role of EGCG as adjuvant in cancer therapy.

Cancer: Pancreatic ductal adenocarcinoma

Action: Anti-proliferative and anti-inflammatory

In the present study, Kürbitz et al., (2011) investigated the in vitro anti-tumoral properties of EGCG on human PDAC (pancreatic ductal adenocarcinoma) cells PancTu-I, Panc1, Panc89 and BxPC3 in comparison with the effects of two minor components of green tea catechins catechin gallate (CG) and epicatechin gallate (ECG). We found that all three catechins inhibited proliferation of PDAC cells in a dose- and time-dependent manner. Interestingly, CG and ECG exerted much stronger anti-proliferative effects than EGCG. Western blot analyses performed with PancTu-I cells revealed catechin-mediated modulation of cell cycle regulatory proteins (cyclins, cyclin-dependent kinases [CDK], CDK inhibitors). Again, these effects were clearly more pronounced in CG or ECG than in EGCG treated cells. Importantly, catechins, in particular ECG, inhibited TNFα-induced activation of NF-κB and consequently secretion of pro-inflammatory and invasion promoting proteins like IL-8 and uPA. Overall, our data show that green tea catechins ECG and CG exhibit potent and much stronger anti-proliferative and anti-inflammatory activities on PDAC cells than the most studied catechin EGCG.

References

Bigelow RLH, & Cardelli JA. (2006). The green tea catechins, (-)-Epigallocatechin-3-gallate (EGCG) and (-)-Epicatechin-3-gallate (ECG), inhibit HGF/Met signaling in immortalized and tumorigenic breast epithelial cells. Oncogene, 25:1922–1930. doi:10.1038/sj.onc.1209227

Chen ZP, Schell JB, Ho CT, Chen KY. (1998). Green tea epigallocatechin gallate shows a pronounced growth-inhibitory effect on cancerous cells but not on their normal counterparts. Cancer Lett,129(2):173-9.


Du GJ, Wang CZ, Qi LW, et al. (2013). The synergistic apoptotic interaction of panaxadiol and epigallocatechin gallate in human colorectal cancer cells. Phytother Res, 27(2):272-7. doi: 10.1002/ptr.4707.


Kavanagh KT, Hafer LJ, Kim DW, et al. (2001). Green tea extracts decrease carcinogen-induced mammary tumor burden in rats and rate of breast cancer cell proliferation in culture. Journal of Cellular Biochemistry, 82(3):387-98. doi:10.1002/jcb.1164


KŸrbitz C, Heise D, Redmer T, et al. (2011). Epicatechin gallate and catechin gallate are superior to epigallocatechin gallate in growth suppression and anti-inflammatory activities in pancreatic tumor cells. Cancer Science, 102(4):728-734. doi: 10.1111/j.1349-7006.2011.01870.x


Okabe S, Suganuma M, Hayashi M, et al. (1997). Mechanisms of Growth Inhibition of Human Lung Cancer Cell Line, PC-9, by Tea Polyphenols. Cancer Science, 88(7):639–643. doi: 10.1111/j.1349-7006.1997.tb00431.x

Lecumberri E, Dupertuis YM, Miralbell R, Pichard C. (2013) Green tea polyphenol epigallocatechin-3-gallate (EGCG) as adjuvant in cancer therapy. Clinical Nutrition. Volume 32, Issue 6, December 2013, Pages 894–903.

Kürbitz C, Heise D, Redmer T, Goumas F, et al. Cancer Science. Online publication Jan 2011. DOI: 10.1111/j.1349-7006.2011.01870.x

Diosgenin

Cancer: Breast, colon, prostate, leukemia, stomach

Action: HER-2, apoptosis, chemo-enhancing

Diosgenin is a plant-derived steroid isolated from Trigonella foenum-graecum (L.).

Breast Cancer; Chemo-enhancing

Diosgenin preferentially inhibited proliferation and induced apoptosis in HER2-overexpressing cancer cells. Furthermore, diosgenin inhibited the phosphorylation of Akt and mTOR, and enhanced phosphorylation of JNK.

The use of pharmacological inhibitors revealed that the modulation of Akt, mTOR and JNK phosphorylation was required for diosgenin-induced FAS suppression. Finally, it was shown that diosgenin could enhance paclitaxel-induced cytotoxicity in HER2-overexpressing cancer cells. These results suggested that diosgenin has the potential to advance as chemo-preventive or chemotherapeutic agent for cancers that overexpress HER2 (Chiang et al., 2007).

Colon Cancer

On 24 hours exposure to diosgenin, MTT cytotoxicity activity reduced by ³50% was achieved at the higher concentrations (i.e., ³80 µmol/L). However, compared with the control, 20 to 60 µmol/L diosgenin reduced the MTT activity only by 5% to 30%. Diosgenin caused a significant time-dependent and dose-dependent decrease in the proliferation of HT-29 cells. Twenty four hours exposure to diosgenin (20 to 100 µmol/L) inhibited cell proliferation compared with untreated cell growth. The in vitro experiment results indicated that diosgenin inhibits cell growth and induces apoptosis in the HT-29 human colon cancer cell line in a dose-dependent manner.

Furthermore, diosgenin induces apoptosis in HT-29 cells at least in part by inhibition of bcl-2 and by induction of caspase-3 protein expression (Raju et al., 2004).

Breast Cancer

The electrochemical behavior of breast cancer cells was studied on a graphite electrode by cyclic voltammetry (CV) and potentiometric stripping analysis (PSA) in unexposed and diosgenin exposed cells. In both cases, only one oxidative peak at approximately +0.75 V was observed. The peak area in PSA was used to study the growth of the cells and the effect of diosgenin on MCF-7 cells. The results showed that diosgenin can effectively inhibit the viability and proliferation of the breast cancer cells (Li et al., 2005).

Leukemia

Cell viability was assessed via an MTT assay. Apoptosis was investigated in terms of nuclear morphology, DNA fragmentation, and phosphatidylserine externalization. Cell cycle analysis was performed via PI staining and flow cytometry (FCM). Western blotting and immunofluorescence methods were used to determine the levels of p53, cell-cycle-related proteins and Bcl-2 family members. Cell cycle analysis showed that diosgenin caused G2/M arrest independently of p53. The levels of cyclin B1 and p21Cip1/Waf1 were decreased, whereas cdc2 levels were increased. The anti-apoptotic Bcl-2 and Bcl-xL proteins were down-regulated, whereas the pro-apoptotic Bax was upregulated.

Diosgenin was hence found to inhibit K562 cell proliferation via cell-cycle G2/M arrest and apoptosis, with disruption of Ca2+ homeostasis and mitochondrial dysfunction playing vital roles (Liu et al., 2005).

In recent years, Akt signaling has gained recognition for its functional role in more aggressive, therapy-resistant malignancies. As it is frequently constitutively active in cancer cells, several drugs are being investigated for their ability to inhibit Akt signaling. Diosgenin (fenugreek), a dietary compound, was examined for its action on Akt signaling and its downstream targets on estrogen receptor positive (ER+) and estrogen receptor negative (ER-) breast cancer (BCa) cells. Additionally, in vivo tumor studies indicate diosgenin significantly inhibits tumor growth in both MCF-7 and MDA-231 xenografts in nude mice. Thus, these results suggest that diosgenin might prove to be a potential chemotherapeutic agent for the treatment of BCa (Srinivasan et al., 2009).

Leukemia, Stomach Cancer

Protodioscin (PD) was purified from fenugreek (Trigonella foenumgraecum L.) and identified by mass spectrometry, and 1H- and 13C-NMR. The effects of PD on cell viability in human leukemia HL-60 and human stomach cancer KATO III cells were investigated. PD displayed strong growth-inhibitory effect against HL-60 cells, but weak growth-inhibitory effect on KATO III cells.

These findings suggest that growth inhibition by PD of HL-60 cells results from the induction of apoptosis by this compound in HL-60 cells (Hibasami et al., 2003).

References

Chiang CT, Way TD, Tsai SJ, Lin JK. (2007). Diosgenin, a naturally occurring steroid, suppresses fatty acid synthase expression in HER2-overexpressing breast cancer cells through modulating Akt, mTOR and JNK phosphorylation. FEBS letters, 581(30), 5735-42. doi:     10.1016/j.febslet.2007.11.021.


Hibasami H, Moteki H, Ishikawa K, et al. (2003). Protodioscin isolated from fenugreek (Trigonella foenumgraecum L.) induces cell death and morphological change indicative of apoptosis in leukemic cell line H-60, but not in gastric cancer cell line KATO III. Int J Mol Med, 11(1):23-6.


Li J, Liu X, Guo M, et al. (2005). Electrochemical Study of Breast Cancer Cells MCF-7 and Its Application in Evaluating the Effect of Diosgenin. Analytical Sciences, 21(5), 561. doi:10.2116/analsci.21.561


Liu MJ, Wang Z, Ju Y, Wong RNS, Wu QY. (2005). Diosgenin induces cell-cycle arrest and apoptosis in human leukemia K562 cells with the disruption of Ca2+ homeostasis. Cancer Chemotherapy and Pharmacology, 55(1), 79-90, doi: 10.1007/s00280-004-0849-3


Raju J, Patlolla JMR, Swamy MV, Rao CV. (2004). Diosgenin, a Steroid Saponin of Trigonella foenum graecum (Fenugreek), Inhibits Azoxymethane-Induced Aberrant Crypt Foci Formation in F344 Rats and Induces Apoptosis in HT-29 Human Colon Cancer Cells. Cancer Epidemiol Biomarkers Prev, 13; 1392.


Srinivasan S, Koduru S, Kumar R, et al. (2009). Diosgenin targets Akt-mediated prosurvival signaling in human breast cancer cells. International Journal of Cancer, 125(4), 961–967. doi: 10.1002/ijc.24419