Effect of insulin-like growth factor-I(IGF-I) on apoptosis of colon cancer cell and its mechanism / 中国普通外科杂志

ABSTRACT

Objective To investigate the effect of IGF-I on the apoptosis and the expression of survivin through the signaling pathway of PI-3K/Akt in colon cancer cell line SW480.Methods When colon cancer cell line SW480 was culfured,Western blot was used to detect the expression of survivin protein in SW480 cells after they were stimulated by different concentrations of IGF-I for different lengths of time.The phosphorylation of Akt in SW480 cells was determined by Western blot after SW480 cells were stimulated by 100 ng/mL IGF-I with in 2 h.Before and after the specific inhibitor LY294002 was treated in SW480 cells to block the pathway of PI-3K/Akt,the phosphorylation level of Akt protein was detected by western blot,survivin protein by western blot and cell immunofluorescence and the cell apoptosis rates of different treated-groups were measured by flow cytometry.Results IGF-I up-regulated the expression of survivin in a dose-dependent and time-dependent manner in colon cancer line SW480(when treated with IGF-I for 12h,the expression of Survivin reached the peak and when treated with 100ng/ml IGF-I,the Survivin reached the highest expression level);IGF-I actived the signaling pathway of PI-3K/Akt of SW480 cells quickly(the expression of p-Akt proteins in SW480 reached the maximum level when cultured with IGF-I for 15 and 30min,but after that they quickly decreased);IGF-I induced survivin expression through the PI-3K/Akt in colon cancer line SW480;IGF-I could inhibited the apoptosis of SW480 cells through the PI-3K/Akt[use of flow cytometry for detection in the blank,stimulation and block groups showed the SW480 cell apoptosis rate was(5.18?0.415)%,(0.85?0.052)%,(3.15?0.411)% respectirely,with significant differences between the groups(P