Glaucocalyxin B induces apoptosis and autophagy in human cervical cancer cells.

Glaucocalyxin (Gln), an ent­kaurane diterpenoid isolated from the Chinese traditional medicine, Rabdosia japonica, represents a novel class of anticancer drugs. GlnA is one of the three major forms of Gln and has demonstrated potent anticancer effects in a variety of cancer types. GlnB has only one structural difference from GlnA, an acetylated hydroxyl group at C14. This acetyl group results in high liposolubility and may enhance the antitumor activity of ent­kaurane diterpenoid GlnB. However, few studies have reported the role of GlnB in cancer. The present study investigated the effect of GlnB in cervical cancer proliferation and cell death. Treatment with GlnB inhibits the proliferation of HeLa and SiHa cervical cancer cell lines in a dose­dependent manner, as assessed by 3­(4,5­dimethylthiazol-2­yl)-2,5 diphenyl tetrazolium bromide assays. In addition, GlnB increases the apoptotic cell population of HeLa and SiHa cells, as determined by fluorescence­activated cell sorting analysis and enhanced poly (ADP­ribose) polymerase 1 cleavage by western blotting. GlnB also induces increased light chain 3 II/I protein cleavage in both cells, indicating the induction of autophagy. Furthermore, GlnB treatment increased the expression of phosphatase and tensin homolog and decreased the expression of phosphorylated­protein kinase B (Akt) in HeLa and SiHa cells, as assessed by western blotting. Taken together, the present results demonstrated that GlnB inhibited the proliferation of human cervical cancer cells in vitro through the induction of apoptosis and autophagy, which may be mediated by the phosphatidylinositol­4,5­bisphosphate 3­kinase/Akt signaling pathway.

LOX-1 deletion limits cardiac angiogenesis in mice given angiotensin II.

Lectin-like oxidized low-density lipoprotein (ox-LDL) receptor-1 (LOX-1) is a major receptor for ox-LDL in endothelial cells. Its activation regulates endothelial proliferation, differentiation, migration and apoptosis. Recent in vitro studies show that LOX-1 activation by ox-LDL and angiotensin II (Ang II) induces angiogenesis via activation of NADPH oxidase and subsequent increase in ROS production. In this study, we investigated the effect of LOX-1 gene deletion (LOX-1 knockout or KO mice) on angiogenesis in response to prolonged Ang II infusion in vivo. Our studies showed that Ang II (vs. saline) infusion enhanced capillary formation in subcutaneously injected Matrigel® plugs. Ang II infusion also resulted in marked angiogenesis in the hearts as determined by CD31 immunopositivity. There was an increased expression (RT-PCR and Western blotting) of CD31 and VEGF in the hearts of mice infused with Ang II, indicating pro-angiogenic miliue. More importantly, LOX-1 KO mice reveled markedly limited angiogenesis in the Matrigel® plugs as well as in the hearts despite similar infusion with Ang II (all P < 0.05 vs. wild-type mice). In addition, the hearts of LOX-1 KO mice had attenuated expression of pro-inflammatory and angiogenic signals MCP-1 and IL-1ß following Ang II Infusion. Lastly, the rise in blood pressure in response to Ang II was less in the LOX-1 KO mice (P < 0.05 vs. wild-type mice). Our findings suggest that LOX-1 participates in angiogenesis in hypertension, which may be related to a state of inflammation.