Inhibition of Akt activation down-regulates the expression of cellular Fas associated death domain-like IL-1β-converting enzyme-inhibitory protein in human colon cancer cell line

作者：Zhou X.-D.^*; Chen H.-X.; Lv N.-H.; Zhu X.; Xu P.; Chen Y.-X.; Yu H.-G.; Yu J.-P.

来源：World Chinese Journal of Digestology, 2007, 15(5): 513-517.

• Cellular Fas associated death domain-like IL-1β- converting enzyme-inhibitory protein
• Colon cancer
• Protein kinase B

AIM: To investigate the changes of cellular Fas associated death domain-like IL-1β-converting enzyme-inhibitory protein (c-FLIP) expression after the inhibition of protein kinase B (PKB/Akt) activation. METHODS: Human colon cancer cell line HT-29 was treated with 10, 20 and 40 nmol/L wortmannin (a specific inhibitor for Akt activation) for 0, 3, 6, 12 and 24 hours. MTT assay was used to detect the proliferation of HT-29 cells. After HT-29 cells were treated with 40 nmol/L wortmannin, the levels of phosphorylated Akt (pAkt) and c-FLIP protein were determined by Western blot, and the transcription of c-FLIP gene was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) at the 0, 3rd, 6th, 12th and 24th hour. RESULTS: Wortmannin suppressed the proliferation of HT-29 cells in a concentration- and time-dependent manner (P < 0.01 or P < 0.05). With the prolonging of treatment time, the level of pAkt protein expression was obviously decreased, while the expression of c-FLIP protein was also down-regulated, with decreased rates of 82 and 91 at the 24th hour, respectively. After wortmannin for 3 hours, the mRNA expression of c-FLIP was decreased to 40 of the control cells, and for 24 hours, it was decreased to 25 of the control ones. CONCLUSION: Wortmannin, a specific inhibitor for Akt activation, may inhibit the proliferation of HT-29 cells in vitro by down-regulation of c-FLIP gene.