ABSTRACT
To investigate the effects of ATRA, acitretin and tazarotene on the growth and apoptosis of human tongue squamous cell carcinoma cell line Tca8113. The effect of retinoids on growth of Tca8113 cells in vitro was examined by MTT assay and Trypan blue exclusion assay. Cell cycle analysis, early apoptosis analysis with double staining with Annexin V-FITC and PI, and active caspase-3 analysis with the staining of FITC-conjugated monoclonal rabbit anti-active caspase-3 antibody were made by flow cytometer. Streptavidin-biotin complex (SABC) immunocytochemical assays were employed for the detections of Bax/Bcl-2 proteins expressions. Our results showed that the retinoids inhibited growth of Tca8113 cells in a dose- and time-dependent manner with maximal inhibition 24 h after treatment of 10-5 mol/L. 10-5 mol/L retinoids altered cell cycle distribution of Tca8113 cells, revealing an increase in G0/G1-phase population, a decrease in S-phase population and the inhibition of G1/S switching. 10-5 mol/L retinoids significantly induced apoptosis of Tca8113 cells (all P<0.05), elevated the cells population with detectable active caspase-3 (P<0.05 for all), increased the number of cells forming Bax and decreased the number of cells forming Bcl-2 significantly (all P<0.05). Acitretin played a most prominent role among the retinoids. It is concluded that the inhibition of cell cycle progress of Tca8113 cells by ATRA, acitretin and tazarotene is one of the possible mechanisms for proliferation arrest of Tca8113 cells elicited by the retinoids. The retinoids mediate apoptosis in Tca8113 cells that may be caspase-dependent through mitochondria pathway. High concentration retinoids inhibit growth of Tca8113 cells in vitro by interfering with proliferation and inducing apoptosis of cells. Acitretin may be an alternative medicine for the prevention and treatment of tongue squamous cell carcinoma.
