Bufalin suppresses hepatocarcinogenesis by targeting ß-catenin/TCF signaling via cell cycle-related kinase.

Hepatocellular carcinoma (HCC) is one of the most aggressive malignant tumors, of which treatment options are limited especially in advanced stage. Bufalin, the major digoxin-like component of the traditional Chinese medicine Chansu, exhibits significant antitumor activities in hepatoma cells, but the potential mechanism is obscure. Cell cycle-related kinase (CCRK) is recently identified to be a crucial oncogenic master regulator to drive hepatocarcinogenesis. Here we investigated the molecular function of bufalin on CCRK-regulated signaling pathway, and expounded the underlying mechanism in HCC suppression. In vitro with PLC5 HCC cells and human immortal LO2 cells, proliferation, malignant transformation and cell cycle progression assays were performed to evaluate the antitumor effect of bufalin. In vivo with xenograft and orthotopic mice models, tumor growths with weight and volume change were assessed with or without bufalin treatment. Western blot, RT-qPCR, immunofluorescence and immunohistochemistry were conducted to examine the expression level of CCRK and ß-catenin/TCF signaling cascade. We revealed that bufalin suppresses PLC5 HCC cell proliferation, transformation and cell cycle progression rather than LO2 cells, which is correlated with CCRK-mediated ß-catenin/TCF signaling. It was also confirmed in mice model. Thus, bufalin is a potential anti-HCC therapeutic candidate through the inhibition of CCRK-driven ß-catenin/TCF oncogenic signaling pathway.

Effects and mechanisms of total Panax notoginseng saponins on proliferation of vascular smooth muscle cells with plasma pharmacology method.

OBJECTIVES: Total Panax notoginseng saponin (TPNS) is extracted from Panax notoginseng. Our previous studies suggested that TPNS could inhibit intimal hyperplasia. This study discussed the impact of TPNS on the proliferation of vascular smooth muscle cells (VSMCs) and revealed the associated mechanisms through cell cycle-related factors and extracellular regulated protein kinase (ERK) signal transduction pathway. METHODS: A VSMC proliferation model induced by platelet-derived growth factor (PDGF) was established to observe the effects of rat drug-containing plasma on VSMC proliferation. KEY FINDINGS: After being stimulated by PDGF, the proliferating cell nuclear antigen (PCNA) and c-fos content increased, while up-regulation of cyclinD1, cyclin-dependent kinase-4 (CDK4) and down-regulation of p21 protein were observed. These changes were inhibited by atorvastatin and TSPN drug-containing plasma, and the inhibitive activity in both groups was not significant. Furthermore, both atorvastatin and TSPN could obviously inhibit the activation of PDGF-induced P-ERK1/2 and increase the content of MKP-1, there were also no significant differences. CONCLUSIONS: These results suggested that atorvastatin and TPNS could inhibit VSMC proliferation by inhibiting the activation of ERK signalling pathway.

Heat-processed neoginseng, KG-135, down-regulates G1 Cyclin-dependent kinase through the proteasome-mediated pathway in HeLa cells.

High temperature heat treatment of ginseng (Panax ginseng, C.A. Meyer) generates KG-135 (heat-processed neoginseng) which contains a mixture of three major ginseng saponins, ginsenosides Rk1, Rg3 and Rg5. Ginsenosides, particularly of the diol-type including Rk1, Rg3 and Rg5, have been shown to induce cell growth arrest in various cell types of human cancer. Herein, we report that KG-135 is able to arrest the cell cycle in human cervix adenocarcinoma HeLa cells. KG-135 arrests cells at the G1 phase of the cell cycle with an IC50 value of 69 microg/ml. The G1 phase arrest is associated with down-regulation of Cyclin D1/Cdk4 and Cyclin B1/Cdc2 activities in cells after treatment with KG-135. Furthermore, down-regulation of G1 Cyclin-dependent kinase activities is kinetically well related to the decreased intracellular protein levels of these kinases. In addition, the decrease in the levels of Cyclin D1/Cdk4 and Cyclin B1, but not of Cdc2, is similarly prevented by co-treatment of cells with MG-132, a potent proteasome inhibitor. Thus, the KG-135-induced arrest of the cell cycle at G1 phase in HeLa cells represents a novel mechanism that involves proteasome-mediated degradation of the Cyclins (Cyclin D1 and B1) and Cdk4 proteins.

Oral grape seed extract inhibits prostate tumor growth and progression in TRAMP mice.

Prostate cancer chemoprevention is an alternative and potential strategy to control this malignancy. Herein, we evaluated the chemopreventive efficacy of grape seed extract (GSE) against prostate cancer in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice where animals were fed with GSE by oral gavage at 200 mg/kg body weight dose during 4 to 28 weeks of age. Our results showed a significant reduction (46%, P < 0.01) in the weight of genitourinary tract organs in the GSE-fed mice. The GSE-fed group of mice had a higher incidence of prostatic intraepithelial neoplasia but showed strong reduction in the incidence of adenocarcinoma compared with mice in control group. Prostate tissue from the GSE group showed approximately 50% (P < 0.001) decrease in proliferating cell nuclear antigen (PCNA)-positive cells and 64% (P < 0.01) reduction in total PCNA protein level compared with the control group; however, GSE increased apoptotic cells by 8-fold. Furthermore, GSE strongly decreased the protein levels of cyclin B1, cyclin A, and cyclin E by 84% (P < 0.05), 96% (P < 0.05), and 89% (P < 0.001), respectively. The protein expression of cyclin-dependent kinases 2 and 6 and Cdc2 was also decreased by more than 90% (P < 0.05) in the prostate from the GSE-fed group. Together, for the first time, we identified that oral GSE inhibits prostate cancer growth and progression in TRAMP mice, which could be mediated via a strong suppression of cell cycle progression and cell proliferation and an increase in apoptosis.

Induction of apoptosis and cell cycle arrest by a chalcone panduratin A isolated from Kaempferia pandurata in androgen-independent human prostate cancer cells PC3 and DU145.

Because of unsatisfactory treatment options for prostate cancer (CaP) there is a need to develop novel preventive approaches for this malignancy. One such strategy is through chemoprevention by the use of non-toxic dietary substances and botanical products. We have shown previously that panduratin A isolated from the extract of Kaempferia pandurata (Zingiberaceae) is a strong inhibitor of cyclooxygenase-2 in RAW264.7 cells and induces apoptosis in HT-29 cells. In the present study, we provide evidence that panduratin A treatment to androgen-independent human CaP cells PC3 and DU145 result in a time and dose-dependent inhibition of cell growth with an IC50 of 13.5-14 microM and no to little effect on normal human prostate epithelial cells. To define the mechanism of these anti-proliferative effects of panduratin A, we determined its effect on critical molecular events known to regulate the cell cycle and the apoptotic machinery. Annexin V/propidium iodide staining provided the evidence for the induction of apoptosis which was further confirmed by the observation of cleavage of poly (ADP-ribose) polymerase and degradation of acinus. Panduratin A treatment to cells was found to result in inhibition of procaspases 9, 8, 6 and 3 with significant increase in the ratio of Bax:Bcl-2, suggesting the involvement of a mitochondrial-dependent apoptotic pathway. Panduratin A-mediated apoptosis was accompanied with upregulation of Fas death receptor and TNF-related apoptosis-inducing ligand (TRAIL). Furthermore, cell cycle analysis using flow cytometry showed that panduratin A treatment of cells resulted in a G2/M arrest in a dose-dependent manner. The immunoblot analysis data revealed that in both cell lines panduratin A treatment resulted in a dose-dependent (i) induction of p21WAF1/Cip1 and p27Kip1, (ii) downregulation of cdks 2, 4 and 6 and (iii) decrease in cyclins D1 and E. These findings suggest that panduratin A may be an effective chemopreventive or therapeutic agent against CaP.

Anti-cancer effect of liriodenine on human lung cancer cells.

Our previous work demonstrated that liriodenine, an isoquinoline alkaloid isolated from plant species of many genera, exhibits a potent cytotoxic effect on various types of human cancer cells. In this study, we investigated the effect of liriodenine on the growth and viability of human lung cancer cells and addressed the underlying mechanism of action. We found that liriodenine suppressed proliferation of A549 human lung adenocarcinoma cells in a dose- and time-dependent manner. Flow cytometric analysis showed that liriodenine blocked cell cycle progression at the G2/M phase. Induction of G2/M arrest by liriodenine was accompanied by reduction of G1 cyclin (D1) and accumulation of G2 cyclin (B1). In vitro kinase activity assay demonstrated that the enzymatic activity of the cyclin B1/cyclin-dependent kinase 1 complex was reduced in liriodenine-treated cells. More importantly, incubation with liriodenine led to activation of caspases and apoptosis in A549 cells. The apoptosis-inducing activity of liriodenine was more apparent when cells were cultured under serum-free conditions. Our results indicate that liriodenine exerts potent anti-proliferative and apoptosis-inducing effects on human lung cancer cells.

The herbal medicine sho-saiko-to inhibits the growth of malignant melanoma cells by upregulating Fas-mediated apoptosis and arresting cell cycle through downregulation of cyclin dependent kinases.

The anti-tumor effect and its mechanism of the herbal medicine sho-saiko-to were investigated on a murine malignant melanoma cell line (Mel-ret). Sho-saiko-to induced apoptotic cell death of Mel-ret cells with a definite increase of cell surface Fas antigen and Fas ligand (FasL). Sho-saiko-to arrested Mel-ret cells in G1 phase by decreasing the expression of cyclin-dependent kinase (cdk) 4 and its homologue cdk6. Kinase activities of cdk4 and cdk6 were identified to be downregulated by sho-saiko-to. Ingredient analysis revealed that baicalin is likely the main active constituent in the upregulation of Fas antigen and Fas ligand, while glycyrrhizin is the main constituent in the inhibition of cdks.