Degradation of Mcl-1 through GSK-3ß Activation Regulates Apoptosis Induced by Bufalin in Non-Small Cell Lung Cancer H1975 Cells.

BACKGROUND/AIMS: Mcl-1, an anti-apoptotic Bcl-2 family member, is often overexpressed in non-small cell lung cancer (NSCLC). Bufalin has been reported to induce apoptosis in various tumor cells. However, there is no report showing that bufalin could downregulate Mcl-1 expression in NSCLC. METHODS: Cell proliferation was analyzed by cell counting kit-8 (CCK-8) assay in H1975 cells. Cell apoptosis was detected by flow cytometry. Mcl-1 mRNA was detected by RT-PCR. The expression of apoptosis-associated proteins in H1975 cells was detected by western blotting. The levels of Mcl-1 ubiquitination and NOXA were analyzed by Immunoprecipitation assay. RESULTS: Cell growth was inhibited by bufalin in a time and dose-dependent manner. Bufalin induced apoptosis in NSCLC cells by activating caspase cascades and downregulating Mcl-1 expression. However, overexpression of Mcl-1 diminished bufalin-induced apoptosis. Furthermore, bufalin did not reduce Mcl-1 mRNA expression in H1975 cells, but strongly promoted Mcl-1 protein degradation. Proteasome inhibitor MG132 markedly prevented the degradation of Mcl-1 and blocked bufalin-induced Mcl-1 reduction. Bufalin did not significantly affect NOXA protein levels, but downregulated the expression of p-GSK-3ß. GSK-3 inhibitor and GSK-3ß siRNA resulted in increased levels of Mcl-1 and reversed the bufalin-induced Mcl-1 degradation. CONCLUSION: Bufalin induced cell apoptosis in H1975 cells may be through downregulation of Mcl-1. Proteasomal degradation of Mcl-1 via GSK-3ß activation was involved in bufalin-induced apoptosis.

Expression of Kin17 promotes the proliferation of hepatocellular carcinoma cells in vitro and in vivo.

Kin17 protein is ubiquitously expressed in mammals and is correlated with vital biological functions. However, little is known about the role of Kin17 in the proliferation of hepatocellular carcinoma cells. The aim of the present study was to investigate whether the upregulation of Kin17 can promote the growth of hepatocellular carcinoma cells. A series of assays was performed to study the effect of Kin17 in the proliferation of hepatocellular carcinoma cells in vitro and in vivo. The western blotting results revealed that Kin17 expression was increased in hepatocellular carcinoma tissues compared with that of the corresponding normal tissues. Moreover, ectopic upregulation of Kin17 expression promoted the growth of hepatocellular carcinoma cells in vitro and in vivo. These results indicated that Kin17 is involved in the tumorigenesis of hepatocellular carcinoma, and that Kin17 has the potential to serve as a therapeutic target for hepatocellular carcinoma.

Study on in-vivo anti-tumor activity of Verbena officinalis extract.

We investigated the anti-tumor effects of Verbena officinalis extract on H22 tumor-bearing mice and its effect on immune function. Mice model of H22 solid tumor was established, the mice were divided into five groups and administered the extract, later, tumors were removed and inhibition rates were calculated; spleens were removed and spleen indices were calculated, and the sheep red blood cell-delayed-type hypersensitivity (SRBC-DTH) and the serum hemolysin level were determined. The Verbena officinalis extract had anti-tumor effect, with the inhibition rate reaching 38.78%, it also increased the spleen index to a certain extent, in addition, the changes in DTA and HA were not obvious compared with the model group. The Verbena officinalis extract had in vivo anti-tumor effect, while causing no damage on the immune function.