Abstract:

Li Min, Xia Yonghua, Liu Dong, Zhang Mengjie, Tian Zhongwei, Li Zhanguo Department of Dermatology, First Affiliated Hospital of Xinxiang Medical University, Xinxiang 453100, Henan, China Corresponding author: Tian Zhongwei, Email: zhonwt@xxmu.edu.cn 【Abstract】 Objective To evaluate effects of downregulation of glucose-6-phosphate dehydrogenase （G6PD） on proliferation and cell cycle distribution of cutaneous squamous cell carcinoma （CSCC） cells. Methods Western blot analysis was performed to measure the protein of G6PD in normally cultured human HaCaT keratinocytes, SCL-1 and A431 CSCC cells. When A431 cells grew to 85% - 90% confluence, a small interfering RNA （siRNA） targeting G6PD （G6PD-siRNA group） and a negative control siRNA （siRNA control group） were transfected into them separately, and untransfected A431 cells served as the untransfected group. CCK-8 assay was performed to evaluate proliferative activity of the A431 cells on days 0, 1, 2, 3 and 4 after transfection, Western blot analysis to measure G6PD, cyclin D1 and CDK4 protein s in A431 cells, and flow cytometry to analyze cell cycle distribution in A431 cells after 48 hours of additional culture. Results The protein of G6PD was significantly higher in normally cultured SCL-1 cells （0.308 ± 0.023） and A431 cells （0.643 ± 0.046） than in HaCaT cells （0.100 ± 0.019, both P < 0.05）, and significantly higher in A431 cells than in SCL-1 cells （P < 0.05）. The G6PD-siRNA group showed significantly decreased protein s of G6PD, cyclin D1 and CDK4 （0.134 ± 0.027, 0.154 ± 0.017 and 0.166 ± 0.017, respectively） compared with the untransfected group （0.425 ± 0.029, 0.344 ± 0.024 and 0.330 ± 0.020 respectively） and siRNA control group （0.444 ± 0.033, 0.350 ± 0.027 and 0.348 ± 0.018 respectively） （all P < 0.05）. Besides, the G6PD-siRNA group showed significantly decreased cellular proliferative activity on days 1 - 4 compared with the siRNA control group and untransfected group （all P < 0.001）, while there were no significant differences between the untransfected group and siRNA control group at any of the time points （all P > 0.05）. Compared with the untransfected group and siRNA control group, the G6PD-siRNA group showed significantly higher proportions of A431 cells in G0/G1 phase （both P < 0.001）, but significantly lower proportions of A431 cells in S phase （both P < 0.001）. Conclusion G6PD may play important roles in the regulation of proliferation and cell cycle distribution of CSCC cells.