Abstract:

Objective To investigate the molecular transduction mechanisms of apoptosis in cutaneous squamous cell carcinoma cell line SCL-1 induced by acitretin. Methods SCL-1 cells were cultured and continuously treated with various concentrations of acitretin. Apoptosis was assessed by enzyme-linked immunosorbent assay （ELISA） in these cells on day 1, 3 and 5. Apoptotic cells were observed by acridine orange staining on day 5. The protein expressions of Fas, FasL, Fas-associated death domain （FADD）, caspase-8, caspase-3 and poly ADP-ribose polymerase （PARP） were examined using Western blot in SCL-1 cells treated with acitretin at 1 × 10-5 mol/L at different time points. Neutralizing anti-Fas antibody （ZB4, 1 μg/mL） was utilized to pretreat SCL-1 cells before the treatment with acitretin, following that, ELISA was done to compare the apoptosis in cells treated with ZB4, acitretin, or the combination of ZB4 and acitretin, respectively. Results Acitretin induced the apoptosis of SCL-1 cells in a dose- and time-dependent manner. Morphologically, acitretin-treated SCL-1 cells showed a typical characteristic of apoptosis. Significant increase in Fas, FasL, and FADD protein expression, as well as the activation of caspase-8, caspase-3 and PARP were induced by the treatment with acitretin. The apoptosis absorbance value was 0.78 ± 0.04 in cells treated with acitretin alone, decreased to 0.41 ± 0.03 in cells treated with ZB4 and acitretin （P < 0.05）, suggesting that ZB4 could block the apoptosis of SCL-1 cells induced by acitretin. Conclusion Acitretin could induce the apoptosis of cutaneous squamous cell carcinoma cells likely by Fas signaling pathway.

Key words: Acitretin, Apoptosis, Carcinoma, squamous cell, Cell line,tumor