RESUMO
Aim To investigate the role of TGF-β3 in the anti-proliferation effect of ursolic acid(UA)in co-lon cancer cells and the possible molecular mechanism underlying this effect.Methods We introduced crys-tal violet staining,flow cytometry and Western blot as-say to determine the effect of UA on proliferation and apoptosis in HCT1 1 6 cells.The levels of TGF-β3, Smad2 /3 and β-catenin in HCT1 1 6 cell were evaluated by RT-PCR and Western blot.Finally,TGF-β3 inhibi-tor and recombinant adenovirus,and luciferase reporter assay were used to analyze the possible mechanism through which TGF-β3 mediated the anti-cancer effect of UA in HCT1 1 6 cells.Results UA inhibited the proliferation and induced apoptosis apparently in HCT1 1 6 cells.UA down-regulated TGF-β3 both in mRNA and in protein level.Meanwhile,UA decreased the phosphorylation of Smad2 /3 concentration depend-ently,although no significant effect was found on the total protein level of Smad2 /3 in HCT1 1 6 cells.Over-expression of TGF-β3 attenuated the inhibitory effect of UA on the proliferation of HCT1 1 6 cells,while the TGF-β3 inhibitor potentiated this effect. UA sup-pressed the transconduction of Wnt/β-catenin signaling in HCT1 1 6 cells through decreasing the level of β-catenin.Exogenous expression of TGF-β3 increased the level of β-catenin and partly reversed the UA-in-duced decrease of β-catenin.However,TGF-β3 inhib-itor potentiated the inhibitory effect of UA on β-catenin in HCT1 1 6 cells.Conclusion The anti-proliferation activity of UA in colon cancer may be partly mediated through down-regulating TGF-β3 to suppress Wnt/β-catenin signaling at least.
RESUMO
Aim To investigate the anti-proliferation effect of resveratrol (Res)on human colon cancer cells and dissect the possible mechanism underlaying this effect.Methods We introduced crystal violet staining and Western blot to analyse the anti-proliferation effect of Res on HCT1 1 6 cells.Then,we used flow cytome-try and Western blot assay to detect the Res induced apoptosis in HCT1 1 6 cells.Next,we employed the well established TCF4 /LEF luciferase reporter to meas-ure the effect of Res on Wnt/β-catenin signaling trans-duction.Finally,we took Western blot and PCR assay to analyse the effect of Res on the expression of β-cate-nin in HCT1 1 6 cells.Results Crystal violet staining and Western blot analysis showed that Res could inhib-it the proliferation of HCT1 1 6 cells in a concentration-and time dependent fashion.What’s more,Res could promote apoptosis in HCT1 1 6 cells.The transcriptional activities of TCF4 /LEF reporter were reduced by Res in a concentration-dependent fashion (P <0.05 when the concentration of Res was 20 μmol·L -1 ,and P <0.01 when the concentration of Res was 40 μmol·L -1 or 80 μmol·L -1 ).Res could decrease not only the protein level of β-catenin in HCT1 1 6 cells,but also the mRNA expression of β-catenin.Conclusion Res can inhibit the proliferation of HCT1 1 6 cells,which may be mediated at least by down-regulating the ex-pression of β-catenin to inhibit the Wnt/β-catenin sig-naling transduction.
RESUMO
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.