Effects of All-traps Retinoic Acid on Expression of XAF1 in Colon Cancer Cell Line

Objective To investigate the effect of all-trans rctinoic acid(ARTA) on XIAP-associated factor 1(XAF1) expression and the growth of human colorectal carcinoma. Methods Lovo cell were treated with various concentrations of ATRA.The mRNA and protein expression of XAF1 were det-ected by Western blot and RT-PCR methods.The cell growth was measured by MTT assay.Transcription activity of XAF1 promoter is examined by luciferase reporter assay. Results The mRNA and protein expression of XAF1 were up regulated by ATRA stimulation in a dose2dependent manner, MTT showed that ATRA could suppress the proliferation of colorectal carcinoma cells. ATRA stimulation also resulted in increase in luciferase activity in cells t ransfected with the pla-smid containing XAF1 promoter region sequences. Conclusion 　ARTA could significantly inhibit the growth of human color2ectal carcinoma cells, and this anti2tumor effect might be related to the up2regulation of XAF1 mRNA and protein by increasing the t ranscription activity of XAF1 promoter.