RUXOLITINIB INHIBITS THE ACTIVATION OF THE JAK2/STAT3 SIGNALING PATHWAY AND IS INVOLVED IN THE REGULATION OF THE PROLIFERATION AND MIGRATION OF HUMAN COLON CANCER CELLS

GUOQIANG QU*, RONGRONG SHEN**, DONGYANG LIU**, YONG XIONG**

*Department of Digestive Medicine, Shanghai Sixth People’s Hospital East Affiliated to Shanghai University of Medicine & Health Sciences, Shanghai, 201308, China - **Department of General Surgery, Shanghai Sixth People’s Hospital East Affiliated to Shanghai University of Medicine & Health Sciences, Shanghai, 201308, China

Objective: To analyze the mechanism by which ruxolitinib inhibits the activation of the JAK2/STAT3 signaling pathway from participating in the regulation of human colon cancer cell proliferation and migration.

Methods: SW480 human colon cancer cell lines were treated with ruxolitinib at concentrations of 1.5, 3.0, 6.0, and 12.0 nmol/L, and the proliferation effect of ruxolitinib was detected by the CCK-8 method. The effect of ruxolitinib on the growth of the SW480 human colon cancer cell line was observed under inverted microscope. The effect of ruxolitinib on the cell cycle of SW480 human colon cancer was detected by flow cytometry. The protein changes of JAK2, p-JAK2, STAT3, and p-STAT3 in SW480 human colon cancer cells were detected by Western Blot.

Results: Ruxolitinib inhibitor had an obvious inhibitory effect on the proliferation of SW480 cells and, with the increase in the concentration of ruxolitinib inhibitor, the inhibitory effect was significantly enhanced, showing drug concentration and time dependence. After ruxolitinib 1.5, 3.0, and 6.0 nmol/L, respectively, were applied to SW480 cells, the number of floating cells increased significantly. The total number of cells decreased significantly with the increase of drug concentration, while cell concentration, aggregation, and fragmentation occurred, and a large number of floating cells appeared; this change was time dependent. Flow cytometry results showed that, after treatment of SW480 human colon cancer cells with ruxolitinib inhibitor at different concentrations for 48 hr, the cycle proportion of the G0/G1 phase in each ruxolitinib concentration group was significantly decreased compared with that of the control group, and the cycle proportion of S phase and G2/M phase were significantly increased compared with the control group (P<0.05). Western Blot results showed that after ruxolitinib 6.0 nmol/L treated SW480 cells, the expression level of p-STAT3 protein was significantly decreased compared with the control group (P<0.05), indicating that ruxolitinib may play an anti-tumor role by inhibiting the JAK2/ STAT3 signaling pathway.

Conclusion: Ruxolitinib significantly inhibited the proliferation of human colon cancer cell line SW480, which may be achieved by inhibiting the JAK2/ STAT3 signaling pathway.