Abstract: Objective To investigate the effect of emodin on proliferation and cell cycle distribution of human oral squamous
carcinoma cells in vitro. Methods Cultured human oral squamous carcinoma Tca8113 cells were treated with 2.5, 5, 10, 20, 40,
60 and 80 μmol/L emodin for 24, 48 or 72 h, with the cells treated with 0.1% DMSO as control. MTT assay and flow cytometry
were used to evaluate the changes in cell proliferation and cell cycle distribution, respectively. Western blotting was employed
to analyze the changes in the expression levels of the cell cycle-related proteins CDK2, cyclin E and P21 after emodin
treatment. Results Emodin significantly inhibited the growth and proliferation of Tca8113 cells within 72 h in a time- and
dose-dependent manner, and caused cell cycle arrest in G0-G1 phase. Western blotting revealed that emodin treatment
significantly lowered the expression levels of CDK2, cyclin E and P21 proteins in Tca8113 cells (P<0.05). Conclusion Emodin
can inhibit the proliferation of Tca8113 cells and affect their cell cycle distribution possibly by inhibiting the signaling
pathways of cell cycle regulation.