Category Archives: PCNA

Paeoniflorin

Cancer: Hepatocellular carcinoma, colorectal, liver

Action: Radio-protective, ameliorated myelosuppression, MDR

Radio-protective

The radio-protective effect of paeoniflorin (PF), a main bioactive component in the traditional Chinese herb peony, on irradiated thymocytes and the possible mechanisms of protection have been investigated. Ionizing radiation can induce DNA damage and cell death by generating reactive oxygen species (ROS).

It was found 60Co γ-ray irradiation increased cell death and DNA fragmentation in a dose-dependent manner while increasing intracellular ROS. Pre-treatment of thymocytes with PF (50–200 µg/ml) reversed this tendency and attenuated irradiation-induced ROS generation. Hydroxyl-scavenging action of PF in vitro was detected through electron spin resonance assay. Several anti-apoptotic characteristics of PF, including the ability to diminish cytosolic Ca2+ concentration, inhibit caspase-3 activation, and up-regulate Bcl-2 and down-regulate Bax in 4 Gy-irradiated thymocytes, were determined.

Extracellular regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 kinase, were activated by 4 Gy irradiation, with their activation partly blocked by pre-treatment of cells with PF. The presence of ERK inhibitor PD98059, JNK inhibitor SP600125 and p38 inhibitor SB203580 decreased cell death in 4 Gy-irradiated thymocytes. These results suggest PF protects thymocytes against irradiation-induced cell damage by scavenging ROS and attenuating the activation of the mitogen-activated protein kinases (Li et al., 2007).

Liver Cancer

Prostaglandin E2 (PGE2) has been shown to play an important role in tumor development and progression. PGE2 mediates its biological activity by binding any one of four prostanoid receptors (EP1 through EP4). Paeoniflorin, a monoterpene glycoside, significantly inhibited the proliferation of HepG2 and SMMC-7721 cells stimulated by butaprost at multiple time points (24, 48, and 72 hours). Paeoniflorin induced apoptosis in HepG2 and SMMC-7721 cells, which was quantified by annexin-V and propidium iodide staining. Our results indicate that the expression of the EP2 receptor and Bcl-2 was significantly increased, whereas that of Bax and cleaved caspase-3 was decreased in HepG2 and SMMC-7721 cells.

Paeoniflorin, which may be a promising agent in the treatment of liver cancer, induced apoptosis in hepatocellular carcinoma cells by down-regulating EP2 expression and also increased the Bax-to-Bcl-2 ratio, thus up-regulating the activation of caspase-3 (Hu et al., 2013).

Colorectal Cancer

Results showed that positive cells of Proliferating Cell Nuclear Antigen (PCNA) in paeoniflorin (PF) and docetaxel-treated group was decreased to 30% and 15% respectively, compared with control group of tumors. But apoptosis cells in docetaxel treated groups studied by TUNEL is increased to 40 ± 1.2% and 30 ± 1.5% respectively, compared with 24 ± 2.3% in negative control. Furthermore, the efficiency of tumor-bearing mice treated by PF was superior to docetaxel in vivo. Overall, PF may be an effective chemo-preventive agent against colorectal cancer HT29 (Wang et al., 2012).

Ameliorates Myelosuppression

The administration of paeoniflorin and albiflorin (CPA) extracted from Paeonia radix, significantly ameliorated myelosuppression in all cases. For the X-ray irradiated mice and the chemotherapy treated mice and rabbits, high dosages of CPA resulted in the recovery of, respectively, 94.4%, 95.3% and 97.7% of hemoglobin content; 67.7%, 92.0% and 94.3% of platelet numbers; 26.8%, 137.1% and 107.3% of white blood cell counts; as well as a reversal in the reduction of peripheral differential white blood cell counts.

There was also a recovery of 50.9%, 146.1% and 92.3%, respectively, in the animals' relative spleen weight. Additionally, a recovery of 35.7% and 87.2% respectively in the number of bone marrow nucleated cells was observed in the radio- and chemo -therapy-treated mice. Bone marrow white blood cell counts also resumed to normal levels (Xu et al., 2011).

MDR

Studies have shown that NF-κB activation may play an essential role in the development of chemotherapy resistance in carcinoma cells. Paeonißorin, a principal bioactive component of the root of Paeonia lactißora, has been reported to exhibit various pharmacological effects. In the present study, Fanh et al. (2012) reported for the first time that paeoniflorin at non-toxic concentrations may effectively modulate multi-drug resistance (MDR) of the human gastric cancer cell line SGC7901/vincristine (VCR) via the inhibition of NF-κB activation and, at least partly, by subsequently down-regulating its target genes MDR1, BCL-XL and BCL-2.

References

Fang S, Zhu W, Zhang Y, Shu Y, Liu P. (2012). Paeoniflorin modulates Multi-drug resistance of a human gastric cancer cell line via the inhibition of NF- κB activation. Mol Med Rep, 5(2):351-6. doi: 10.3892/mmr.2011.652.


Hu S, Sun W, Wei W, et al. (2013). Involvement of the prostaglandin E receptor EP2 in paeoniflorin-induced human hepatoma cell apoptosis. Anti-cancer Drugs, 24(2):140-9. doi: 10.1097/CAD.0b013e32835a4dac.


Li CR, Zhou Z, Zhu D, et al. (2007). Protective effect of paeoniflorin on irradiation-induced cell damage involved in modulation of reactive oxygen species and the mitogen-activated protein kinases. The International Journal of Biochemistry & Cell Biology, 39(2):426–438


Wang H, Zhou H, Wang CX, et al. (2012). Paeoniflorin inhibits growth of human colorectal carcinoma HT 29 cells in vitro and in vivo. Food Chem Toxicol, 50(5):1560-7. doi: 10.1016/j.fct.2012.01.035.


Xu W, Zhou L, Ma X, et al. (2011). Therapeutic effects of combination of paeoniflorin and albiflorin from Paeonia radix on radiation and chemotherapy-induced myelosuppression in mice and rabbits. Asian Pac J Cancer Prev, 12(8):2031-7.

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.

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.

Spica Prunellae Extract

Cancer: Colorectal

Action: Promotes apoptosis, anti-angiogenic, induces angiogenesis

Constitutive activation of STAT3 is one of the major oncogenic pathways involved in the development of various types of malignancies including colorectal cancer (CRC); and thus becomes a promising therapeutic target. Spica Prunellae has long been used as an important component in many traditional Chinese medicine formulas to clinically treat CRC. Previously, Lin et al., (2013) found that Spica Prunellae inhibits CRC cell growth through mitochondrion-mediated apoptosis. Furthermore, we demonstrated its anti-angiogenic activities in vivo and in vitro.

CRC mouse xenograft model was generated by subcutaneous injection of human colon carcinoma HT-29 cells into nude mice. Animals were given intra-gastric administration with 6 g/kg of the ethanol extract of Spica Prunellae (EESP) daily, 5 days a week for 16 days. Body weight and tumor growth were measured every two days. Tumor growth in vivo was determined by measuring the tumor volume and weight. HT-29 cell viability was examined by MTT assay. Cell apoptosis and proliferation in tumors from CRC xenograft mice was evaluated via immunohistochemical staining (IHS) for TUNEL and PCNA, and the intratumoral microvessel density (MVD) was examined by using IHS for the endothelial cell-specific marker CD31. The activation of STAT3 was evaluated by determining its phosphorylation level using IHS. The mRNA and protein expression of Bcl-2, Bax, Cyclin D1, VEGF-A and VEGFR2 was measured by RT-PCR and IHS, respectively.

EESP treatment reduced tumor volume and tumor weight but had no effect on body weight change in CRC mice; decreasedanti-angiogenic cell viability in a dose-dependent manner, suggesting that EESP displays therapeutic efficacy against colon cancer growth in vivo and in vitro, without apparent toxicity. In addition, EESP significantly inhibited the phosphorylation of STAT3 in tumor tissues, indicating its suppressive action on the activation of STAT3 signaling. Consequently, the inhibitory effect of EESP on STAT3 activation resulted in an increase in the pro-apoptotic Bax/Bcl-2 ratio, decrease in the expression of the pro-proliferative Cyclin D1 and CDK4, as well as down-regulation of pro-angiogenic VEGF-A and VEGFR-2 expression. Finally, these molecular effects led to the induction of apoptosis, the inhibition of cell proliferation and tumor angiogenesis.

Spica Prunellae possesses a broad range of anti-cancer activities due to its ability to affect STAT3 pathway, suggesting that Spica Prunellae could be a novel potent therapeutic agent for the treatment of CRC.

Reference

Lin W, Zheng L, Zhuang Q, Zhao J, et al. (2013) Spica prunellae promotes cancer cell apoptosis, inhibits cell proliferation and tumor angiogenesis in a mouse model of colorectal cancer via suppression of stat3 pathway. BMC Complement Altern Med. 2013 Jun 24;13(1):144.