Abstract:

Background and purpose: Aquaporin 5 (AQP-5) was overexpressed in colon cancer tissues, and AQP-5 was related to occurrence, progress of colon cancer. But the relationship between AQP-5, signaling pathway in colon cancer cells is still not clear. The purpose of this study was to investigate the effects of AQP-5 on the signaling pathway of human colon cancer HT-29 cells by inhibiting the expression of endogenous AQP-5 in colon cancer cell line HT-29 via AQP-5-siRNA transfection. Methods: Human colon cancer HT-29 cells were cultured in vitro and the cells in logarithm growth period were used. RNA interference (siRNA) technology was used to inhibit the expression of endogenous AQP-5 and Western blot was used to detect the inhibition efficiency of AQP-5-siRNA in HT-29 cells. MTT assay were used to detect the cell growth inhibition rate; Flow cytometry (FCM) was used to measure the cell apoptosis rate; To observe the effects of AQP-5-siRNA transfection on AKT, ERK, JNK and P38 pathway of HT-29 cells, the levels of the expression of AKT, ERK, JNK and P38 phosphorylation protein and total protein were measured by Western blot. Results: The results of Western blot showed that AQP-5 expression was suppressed by over 90% in HT-29 cells after AQP-5-siRNA transfection. MTT showed that the proliferation inhibition rate was increased significantly in HT-29 cells after AQP-5-siRNA transfection rather than NS-siRNA transfection (P<0.05); FCM analysis showed that AQP-5-siRNA transfection induced HT-29 cell apoptosis (P<0.05). Western blot showed that compared with NS- siRNA negative control group, AQP-5-siRNA transfection decreased the rates of p-p38 and p38. However, the level of the expression of AKT, ERK, JNK phosphorylation protein was not different between AQP-5-siRNA transfection group and NS-siRNA negative control group (P>0.05). Conclusion: The RNA interference (siRNA) technology targeting to AQP-5 inhibited the expression of endogenous AQP-5 in HT-29 cells, inhibited the cell proliferation, and induced the cell apoptosis, and the effect may be related with its decreasing the rate of p-p38 and p38.

Key words: Aquaporin 5, Colonic neoplasms, Signaling pathway