attenuation of immune suppression

Cancer:
Lung cancer, breast cancer, leukemia, gastric, colon

Action: Anti-inflammatory, induces apoptosis, inhibits HIF-1 α, immunomodulatory

Chrysin (5,7-dihydroxyflavone) is a natural and biologically active compound extracted from many plants (including Scutellaria baicalensis (Georgi), Passiflora caerulea (L.), Passiflora incarnate (L.))., honey, and propolis. It possesses potent anti-inflammatory, anti-oxidant properties, promotes cell death, and perturbs cell-cycle progression. Chrysin induced p38-MAPK activation, and using a specific p38-MAPK inhibitor, SB203580, attenuated chrysin-induced p21 (Waf1/Cip1) expression (Weng et al., 2005).

MDR; NSCLC

Chrysin is a major flavonoid in Scutellaria baicalensis, a widely used traditional Chinese and Japanese medicine. Novel links of pro-inflammatory signals, AKR1C1/1C2 expression and drug resistance in human non-small lung cancer have been demonstrated, and the protein kinase C pathway may play an important role in this process. It is thought that chrysin may act as a potential adjuvant therapy for drug-resistant non-small lung cancer, especially for those with AKR1C1/1C2 overexpression (Wang et al., 2007).

Gastric Cancer, Colon Cancer

Additionally, derivatives of chrysin have been shown to have strong activities against SGC-7901 human gastric cell line and HT-29 human colon cancer cell lines (Zheng et al., 2003).

Breast Cancer

While Chrysin is a potent breast cancer resistance protein inhibitor, it was found to have no significant effect on toptecan pharmacokinetics in rats (Zhang et al., 2005).

VEGF, HIF-1

Chrysin was found to inhibit hypoxia-inducible factor-1α (HIF-1α) expression through AKT signaling. Inhibition of HIF-1α by chrysin resulted in abrogation of vascular endothelial growth factor expression (Fu et al., 2007).

Leukemia

Chrysin has been shown to inhibit proliferation and induce apoptosis, and is more potent than other tested flavonoids in leukemia cells, where chrysin is likely to act via activation of caspases and inactivation of Akt signaling in the cells (Khoo et al., 2010).

Immune

The chemo-preventive action of chrysin has been found to specifically inhibit the enzymatic activity of IDO-1 but not mRNA expression in human neuronal stem cells (hNSC), confirmed by cell-based assay and qRT-PCR. These results suggest that attenuation of immune suppression via inhibition of IDO-1 enzyme activity may be one of the important mechanisms of polyphenols in chemoprevention or combinatorial cancer therapy (Chen et al., 2012).

References

Chen SS, Corteling R, Stevanato L, Sinden J. (2012). Polyphenols Inhibit Indoleamine 3,5-Dioxygenase-1 Enzymatic Activity — A Role of Immunomodulation in Chemoprevention. Discovery Medicine.

Fu B, Xue J, Li Z, et al. (2007). Chrysin inhibits expression of hypoxia-inducible factor-1 α through reducing hypoxia-inducible factor-1 α stability and inhibiting its protein synthesis. Mol Cancer Ther, 6:220. doi: 10.1158/1535-7163.MCT-06-0526

Khoo BY, Chua SL, Balaram P. (2010). Apoptotic Effects of Chrysin in Human Cancer Cell Lines. Int. J. Mol. Sci, 11(5), 2188-2199. doi:10.3390/ijms11052188

Wang HW, Lin CP, Chiu JH, et al. (2007). Reversal of inflammation-associated dihydrodiol dehydrogenases (AKR1C1 and AKR1C2) overexpression and drug resistance in nonsmall cell lung cancer cells by wogonin and chrysin. International Journal of Cancer, 120(9), 2019-2027.

Weng MS, Ho YS, Lin JK. (2005). Chrysin induces G1 phase cell-cycle arrest in C6 glioma cells through inducing p21Waf1/Cip1 expression: involvement of p38 mitogen-activated protein kinase. Biochem Pharmacol, 69(12):1815-27.

Zhang S, Wang X, Sagawa K, Morris ME. (2005). Flavonoids chrysin and benzoflavone, potent breast cancer resistance protein inhibitors, have no significant effect on topotecan pharmacokinetics in rats or mdr1a/1b (,äì/,äì) mice. Drug Metabolism and Disposition, 33(3), 341-348.

Zheng X, Meng WD, Xu YY, Cao JG, & Qing FL. (2003). Synthesis and anti-cancer effect of chrysin derivatives. Bioorganic & Medicinal Chemistry Letters, 13(5), 881-884.

Cancer: Colorectal., prostate, pancreatic

Action: MDR, chemo-preventive activity, anti-inflammatory, attenuation of immune suppression

Chemo-preventive Activity

Curcumin is a naturally occurring, dietary polyphenolic phytochemical that is under preclinical trial evaluation for cancer-preventive drug development. It is derived from the rhizome of Curcuma longa L. and has both anti-oxidant and anti-inflammatory properties; it inhibits chemically-induced carcinogenesis in the skin, forestomach, and colon when it is administered during initiation and/or postinitiation stages. Chemo-preventive activity of curcumin is observed when it is administered prior to, during, and after carcinogen treatment as well as when it is given only during the promotion/progression phase (starting late in premalignant stage) of colon carcinogenesis (Kawamori et al., 1999)

Anti-inflammatory

With respect to inflammation, in vitro, it inhibits the activation of free radical-activated transcription factors, such as nuclear factor κB (NFκB) and AP-1, and reduces the production of pro-inflammatory cytokines such as tumor necrosis factor-α (TNFα), interleukin-1β (IL-1β), and interleukin-8 (Chan et al., 1998)

Prostate Cancer

In addition, NF-kappaB and AP-1 may play a role in the survival of prostate cancer cells, and curcumin may abrogate their survival mechanisms (Mukhopadhyay et al., 2001).

Pancreatic Cancer

In patients suffering from pancreatic cancer, orally-administered curcumin was found to be well-tolerated and despite limited absorption, had a reasonable impact on biological activity in some patients. This was attributed to its potent nuclear factor-kappaB (NF-kappaB) and tumor-inhibitory properties, against advanced pancreatic cancer (Dhillon et al., 2008)

MDR

Curcumin, the major component in Curcuma longa (Jianghuang), inhibited the transport activity of all three major ABC transporters, i.e. Pgp, MRP1 and ABCG2 (Ganta et al., 2009).

Curcumin reversed MDR of doxorubicin or daunorubicin in K562/DOX cell line and decreased Pgp expression in a time-dependent manner (Chang et al., 2006). Curcumin enhanced the sensitivity to vincristine by the inhibition of Pgp in SGC7901/VCR cell line (Tang et al., 2005). Moreover, curcumin was useful in reversing MDR associated with a decrease in bcl-2 and survivin expression but an increase in caspase-3 expression in COC1/DDP cell line (Ying et al., 2007).

The cytotoxicity of vincristine and paclitaxel were also partially restored by curcumin in resistant KBV20C cell line. Curcumin derivatives reversed MDR by inhibiting Pgp efflux (Um et al., 2008). A chlorine substituent at the meta-or para-position on benzamide improved MDR reversal [72]. Bisdemethoxycurcumin modified from curcumin resulted in greater inhibition of Pgp expression (Limtrakul et al., 2004).

Attenuation of Immune Suppression

Curcumin (a chalcone) exhibited toxicity to human neural stem cells (hNSCs). Although oridonin (a diterpene) showed a null toxicity toward hNSCs, it repressed the enzymatic function only marginally in contrast to its potent cytotoxicity in various cancer cell lines. While the mode of action of the enzyme-polyphenol complex awaits to be investigated, the sensitivity of enzyme inhibition was compared to the anti-proliferative activities toward three cancer cell lines.

The IC50s obtained from both sets of the experiments indicate that they are in the vicinity of micromolar concentration with the enzyme inhibition slightly more active.

These results suggest that attenuation of immune suppression via inhibition of IDO-1 enzyme activity may be one of the important mechanisms of polyphenols in chemoprevention or combinatorial cancer therapy (Chen et al., 2012).

Cancer Stem Cells

In cancers that appear to follow the stem cell model, pathways such as Wnt, Notch and Hedgehog may be targeted with natural compounds such as curcumin or drugs to reduce the risk of initiation of new tumors. Disease progression of established tumors could also potentially be inhibited by targeting the tumorigenic stem cells alone, rather than aiming to reduce overall tumor size.

Cancer treatments could be evaluated by assessing stem cell markers before and after treatment. Targeted stem cell specific treatment of cancers may not result in 'complete' or 'partial' responses radiologically, as stem cell targeting may not reduce the tumor bulk, but eliminate further tumorigenic potential. These changes are discussed using breast, pancreatic, and lung cancer as examples (Reddy et al., 2011).

Multiple Cancer Effects; Cell-signaling

Curcumin has been shown to interfere with multiple cell signaling pathways, including cell-cycle (cyclin D1 and cyclin E), apoptosis (activation of caspases and down-regulation of anti-apoptotic gene products), proliferation (HER-2, EGFR, and AP-1), survival (PI3K/AKT pathway), invasion (MMP-9 and adhesion molecules), angiogenesis (VEGF), metastasis (CXCR-4) and inflammation (NF- κB, TNF, IL-6, IL-1, COX-2, and 5-LOX).

The activity of curcumin reported against leukemia and lymphoma, gastrointestinal cancers, genitourinary cancers, breast cancer, ovarian cancer, head and neck squamous cell carcinoma, lung cancer, melanoma, neurological cancers, and sarcoma reflects its ability to affect multiple targets (Anand et al., 2008).

Anti-inflammatory; Cell-signaling

Curcumin, a liposoluble polyphenolic pigment isolated from the rhizomes of Curcuma longa L. (Zingiberaceae), is another potential candidate for new anti-cancer drug development. Curcumin has been reported to influence many cell-signaling pathways involved in tumor initiation and proliferation. Curcumin inhibits COX-2 activity, cyclin D1 and MMPs overexpresion, NF-kB, STAT and TNF-alpha signaling pathways and regulates the expression of p53 tumor suppressing gene.

Curcumin is well-tolerated but has a reduced systemic bioavailability. Polycurcumins (PCurc 8) and curcumin encapsulated in biodegradable polymeric nanoparticles showed higher bioavailability than curcumin together with a significant tumor growth inhibition in both in vitro and in vivo studies (Cretu et al., 2012). Curcumin also sensitizes tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis through reactive oxygen species-mediated up-regulation of death receptor 5 (DR5) (Jung et al., 2005).

Curcumin and bioavailability

Curcumin, a major constituent of the spice turmeric, suppresses expression of the enzyme cyclooxygenase 2 (Cox-2) and has cancer chemo-preventive properties in rodents. It possesses poor systemic availability. Marczylo et al. (2007) explored whether formulation with phosphatidylcholine increases the oral bioavailability or affects the metabolite profile of curcumin. Their results suggest that curcumin formulated with phosphatidylcholine furnishes higher systemic levels of parent agent than unformulated curcumin.

Curcuminoids are poorly water-soluble compounds and to overcome some of the drawbacks of curcuminoids, Aditya et al. (2012) explored the potential of liposomes for the intravenous delivery of curcuminoids. The curcuminoids-loaded liposomes were formulated from phosphatidylcholine (soy PC). Curcumin/curcuminoids were encapsulated in phosphatidylcholine vesicles with high yields. Vesicles in the size range around 200 nm were selected for stability and cell experiments. Liposomal curcumin were found to be twofold to sixfold more potent than corresponding curcuminoids. Moreover, the mixture of curcuminoids was found to be more potent than pure curcumin in regard to the anti-oxidant and anti-inflammatory activities (Basnet et al., 2012). Results suggest that the curcumin-phosphatidylcholine complex improves the survival rate by increasing the anti-oxidant activity (Inokuma et al., 2012). Recent clinical trials on the effectiveness of phosphatidylcholine formulated curcumin in treating eye diseases have also shown promising results, making curcumin a potent therapeutic drug candidate for inflammatory and degenerative retinal and eye diseases (Wang et al., 2012). Data demonstrate that treatment with curcumin dissolved in sesame oil or phosphatidylcholine curcumin improves the peripheral neuropathy of R98C mice by alleviating endoplasmic reticulum stress, by reducing the activation of unfolded protein response (Patzk- et al., 2012).

References

Aditya NP, Chimote G, Gunalan K, et al. (2012). Curcuminoids-loaded liposomes in combination with arteether protects against Plasmodium berghei infection in mice. Exp Parasitol, 131(3):292-9. doi: 10.1016/j.exppara.2012.04.010.

Anand P, Sundaram C, Jhurani S, Kunnumakkara AB, Aggarwal BB. (2008). Curcumin and cancer: An 'old-age' disease with an 'age-old' solution. Cancer Letters, 267(1):133–164. doi: 10.1016/j.canlet.2008.03.025.

Basnet P, Hussain H, Tho I, Skalko-Basnet N. (2012). Liposomal delivery system enhances anti-inflammatory properties of curcumin. J Pharm Sci, 101(2):598-609. doi: 10.1002/jps.22785.

Chan MY, Huang HI, Fenton MR, Fong D. (1998). In Vivo Inhibition of Nitric Oxide Synthase Gene Expression by Curcumin, a Cancer-preventive Natural Product with Anti-Inflammatory Properties. Biochemical Pharmacology, 55(12), 1955-1962.

Chang HY, Pan KL, Ma FC, et al. (2006). The study on reversing mechanism of Multi-drug resistance of K562/DOX cell line by curcumin and erythromycin. Chin J Hem, 27(4):254-258.

Chen SS, Corteling R, Stevanato L, Sinden J. (2012). Polyphenols Inhibit Indoleamine 3,5-Dioxygenase-1 Enzymatic Activity — A Role of Immunomodulation in Chemoprevention. Discovery Medicine.

Cre ţ u E, Trifan A, Vasincu A, Miron A. (2012). Plant-derived anti-cancer agents – curcumin in cancer prevention and treatment. Rev Med Chir Soc Med Nat Iasi, 116(4):1223-9.

Dhillon N, Aggarwal BB, Newman RA, et al. (2008). Phase II trial of curcumin in patients with advanced pancreatic cancer. Clin Cancer Res,14(14):4491-9. doi: 10.1158/1078-0432.CCR-08-0024.

Ganta S, Amiji M. (2009). Coadministration of paclitaxel and curcumin in nanoemulsion formulations To overcome Multi-drug resistance in tumor cells. Mol Pharm, 6(3):928-939. doi: 10.1021/mp800240j.

Inokuma T, Yamanouchi K, Tomonaga T, et al. (2012). Curcumin improves the survival rate after a massive hepatectomy in rats. Hepatogastroenterology, 59(119):2243-7. doi: 10.5754/hge10650.

Jung EM, Lim JH, Lee TJ, et al. (2005). Curcumin sensitizes tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis through reactive oxygen species-mediated up-regulation of death receptor 5 (DR5). Carcinogenesis, 26(11):1905-1913.