Study on the relationship between Insulin-like growth factor binding protein 5 and anti-proliferating effect of tetrandrine on human colon cancer cells / 中国药理学通报

Aim To investigate the anti-proliferating effect of tetrandrine ( Tet ) on colon cancer cells and its possible molecular mechanism. Methods We intro-duced crystal violet staining and flow cytometry to ana-lyze the effect of Tet on proliferation in LoVo cells. Flow cytometry was used to detect the effect of Tet on apoptosis in LoVo cells. Western blot assay was taken to analyze the effect of Tet on the expression of insulin-like growth factor binding protein 5 ( IGFBP5 ) . Final-ly, luciferase reporter assay, recombinant adenovirus mediated over-expression or silence of IGFBP5 were used to analyze the possible role of IGFBP5 in the anti-proliferating effect of Tet on colon cancer cells. Re-sults Crystal violet staining and flow cytometery anal-ysis results showed that Tet could exert an anti-prolifer-ating effect and induce apoptosis in LoVo cells. Tet de-creased the expression of IGFBP5 in a concentration-dependent manner. Tet inhibited the transcriptional ac-tivity of pTOP-luc reporter, which could be reversed by exogenous expression of IGFBP5 mostly. Similar results were found in the expression of c-Myc, but IGFPB5 knockdown couldn’ t reverse this effect. Conclusion Tet can inhibit the proliferation of colon cancer cells, and this effect may be mediated by down-regulating the expression of IGFBP5 to inhibit Wnt/β-catenin signa-ling transduction partly.

Modulation of GSK-3βactivity in cancer treatment / 中国药理学通报

As the major member of serine/threonine protein ki-nases family, glycogen synthase kinase 3β ( GSK-3β) has well characterized roles in the development of a variety of diseases. However, it is noticed that modulation of GSK-3β in tumor pro-gress is two-faced. Once the activity of GSK-3βas a“pro-onco-genic factor” is inhibited, opposing role as a“tumor suppressor”can also be disrupted, which will trigger the consequent side effect on activation of Wnt/β-catenin signaling pathway. The is-sue has placed a major obstacle to anti-GSK-3β in cancer treat-ment. In fact, functional compartmentalization of a large number of intracellular signaling events cross-talked with GSK-3β can prevent their mutual interference and determine the cell fate. Therefore, understanding the specific mechanisms of GSK-3β in regulation of diverse signaling systems or refinement of a sub-strate competitive inhibitor may have great significance to exploit approaches selectively target GSK-3β in tumor treatment.