Abstract: Objective To study the effect of imiquimod on SCL-1 cell proliferation and apoptosis.Methods SCL-1 cells were cultured in 96-well microplates and treated with various concentrations of imiquimod for different durations.The proliferation of SCL-1 cells was measured using MTT assay,the morphological alterations observed by an inverted microscope,the early apoptosis of cells evaluated by flow cytometry with Annexin V and PI,and the morphological changes at late apoptosis observed by acridine orange staining. Cell death detection kit was utilized to count the apoptosis cells,RT-PCR and immunohistochemical method to detect the expressions of apoptosis-associated genes,Fas and bcl-2.Results Imiquimod could significantly inhibit the growth,and cause morphological changes,of SCL-1 cells.The early apoptosis rate was 47.23% in SCL-1 cells treated with 0.15 mg/ml imiquimod for 24 h,and was the highest among the cells treated with various durations of imiquimod.Typically apoptotic bodies were observed in the SCL-1 cells treated with imiquimod for 48 h.Imiquimod induced the apoptosis of SCL-1 cells in a time-and dose-dependent fashion.Moreover,the expression of Fas was elevated and that of bcl-2 was decreased by the treatment of imiquimod.Conclusion Imiquimod could markedly inhibit the proliferation of SCL-1 cells and induce the apoptosis of them.

Key words: Carcinoma,squamous cell, Cell line,tumor, Imiquimod, Cell proliferation, Cell apoptosis