Abstract: Objective: To study the effects of quercetin (Qu) on the proliferative activity of human skin squamous cell carcinoma cells (A431). Methods: The viability, proliferation and apoptosis of A431 cells treated by QU of different concentration (10, 50, 100 and 200 μg/mL) were respectively detected by CCK-8 assay, Western blot and flow cytometry assay. The impacts of Qu on activation of sphingosine kinase 2 (Sphk2) in A431 cells were detected by Western blot. Results: After treated for 96h by QU of concentration 10, 50, 100 and 200 μg/mL, the OD readings were (0.654±0.098),（0.527±0.089）,（0.412±0.076）and（0.309±0.054）, respectively; the cell activities were (81.3±4.6)%, (56.3±4.9)%, (37.4±4.2)%, (19.4±3.6)% , respectively and the apoptosis rate of A431 cells were (6.43±1.09)%, (14.77±1.26)%,（21.30±1.36）% and (29.84±1.26)% , respectively. Qu dose-dependently inhibited the expression levels of Sphk2 in A431 cells, and the cell activity of A431 cells in Qu+Sphk2 mimics was higher and the apoptosis rate was lower than that in Qu group (Ps<0.05). Conclusion: Qu could inhibit the proliferative activity of human skin squamous cell carcinoma cells through decreasing the activation of Sphk2 pathway.

Key words: quercetin, human skin squamous cell carcinoma cells, sphingosine kinase 2, apoptosis