Cyclooxygenase-2-independent mechanism study of selective cyclooxygenase-2 inhibitor on proliferation and apoptosis of colon caner cells

Objective To investigate the influence of selective COX 2 inhibitor NS 398 on proliferation and apoptosis of colorectal cancer and reveal the potential COX2 independent mechanism of NS 398 effect on colorectal cancer cell.Methods By using RT PCR assay,thye expression level of COX 2 mRNA in human colorectal cancer cell line SW480 was detected.After SW480 cells were treated with NS 398,MTT assay and flow cytometry were used to measure the proliferation and apoptosis in 0,24,48,72 h respectively.The expression of Cyclin D1 and Bcl 2 was detected by Western blot before and after treatment with NS 398.Results COX 2 mRNA expression was not detected in colorectal cancer cell line SW480.The ratios of S and G 2/M percentage,and Cyclin D1 and Bcl 2 expression in blank group and NS 398 treated group were 1.28 and 1.55 ( P 0.01),and 6.41 and 2.74 ( P 0.01),respectively.NS 398 inhibited the cells proliferation and induced apoptosis in a dose and time dependent manner and resulted in significant downregulation of CyclinD1 and Bcl 2.Conclusion NS 398 may inhibit the proliferation and induce apoptosis of colon cancer cell lines SW480 through down regulating the expression of Cyclin D1 and Bcl 2.The COX 2 independent effect did exist.It may be a new target of selective COX 2 inhibitor effect on colon cancer.