Effects of inhibition of glucose-6-phosphate dehydrogenase expression on proliferation and cell cycle distribution of A431 cells

Objective To evaluate effects of downregulation of glucose-6-phosphate dehydrogenase (G6PD) expression on proliferation and cell cycle distribution of cutaneous squamous cell carcinoma (CSCC) cells. Methods Western blot analysis was performed to measure the protein expression 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 expressions in A431 cells, and flow cytometry to analyze cell cycle distribution in A431 cells after 48 hours of additional culture. Results The protein expression 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). 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. Key words: Carcinoma, squamous cell; Glucosephosphate dehydrogenase; Cell proliferation; Cell cycle; A431 cells