Abstract: Objective: To detect the changes of cell proliferation and chemotherapeutic drugs sensitivity of human squamous cell carcinoma of tongue after suppressor of cytokine signaling-1 (SOCS1) gene silencing, and to explore the SOCS1 as the target of anti-tumor therapy through enhancing the function of chemotherapeutic drugs. Methods: Western blot, PCR and real-time PCR were used to verify the down regulation of SOCS1 human squamous cell carcinoma of tongue cell (CAL27) after transfection; and the change of chemotherapeutic drugs sensitivity was detected by MTT assay; cell counting was used to measure cell proliferation rate; flow cytometry was used to detect the cell cycle. Results: Results of RT-PCR and western blot showed that the expression levels of SOCS1 mRNA and protein were significantly decreased in small hairpin SCOS1 (shSOCS1) transfected CAL27 cells. After the silence of SOCS1, the median inhibitory concentration of chemotherapeutic drugs for CAL27 cells decreased significantly (P<0.01). 72 hours after the SOCS1 silencing, the cell count of shSOCS1 cells dropped significantly compared with that of control group (P<0.05). The cell cycle arrest was promoted at the G0/G1 phase, but the percentage of cells in S phase and G2/M decreased compared to that of control groups (P<0.05). Conclusion: Inhibition of SOCS1 gene expression decreases the proliferation ability of human squamous cell carcinoma of tongue cell line CAL27, and enhances the sensitivity of CAL27 cells to chemotherapeutic drugs.

Key words: Human squamous cell carcinoma of tongue , Gene silencing , Cell proliferation , Chemotherapeutic drugs, Suppressor of cytokine signaling proteins