[Effects and mechanisms of phosphatidylinositol 3 kinase B signal pathway on colon cancer cell SW480].

Objective: To explore the effects of phosphatidylinositol 3 kinase-protein kinase B (PI3K-AKT) signal pathway on the proliferation, apoptosis and invasiveness of colon cancer cell line SW480 and explore its possible mechanisms.

Methods: SW480 cells were cultured with various concentrations (0, 5, 10, 20 and 40 µmol/L) of LY294002 and methyl thiazolyl tetrazolium (MTT) assay was conducted after 24, 48 and 72 hours. SW480 cells were cultured for 24 hours with various concentrations (0, 10, 20 and 40 µmol/L) of LY294002. The apoptotic rate was measured by flow cytometry (FCM). The difference of invasiveness was examined by Transwell invasion test. Western blotting was used to examine the expressions of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9). One-way ANOVA was used for statistical analysis.

Results: MTT assay showed that the proliferation rate of all SW480 cells except for the lowest concentration group (5 µmol/L) was lower than the control group (0 µmol/L) and a time-dosage dependence existed (all P < 0.05). The results of FCM demonstrated that the apoptotic rates of 10, 20 and 40 µmol/L groups were 13.3% ± 0.9%, 30.9% ± 2.5% and 41.2% ± 4.1% respectively, and were all significantly higher than control group (5.2% ± 1.8%, all P < 0.05). The number of cells penetrating through the membrane of 10, 20 and 40 µmol/L groups were 87 ± 6, 65 ± 7 and 46 ± 11 respectively. All invasiveness groups were all lower than control group (100 ± 10, all P < 0.05) except the 10 µmol/L concentration group (P = 0.096). Western blotting showed that the expressions of VEGF and MMP-9 were all lower than control group (all P < 0.05).

Conclusions: PI3K-AKT signal pathway plays an important role in the proliferation, apoptosis and inhibition of colonic cancer cells. Its mechanism is probably related with the inhibitions of VEGF and MMP-9. PI3K-AKT signal pathway may become a potential target for the treatment of colon cancer.