Abstract: Objective To investigate the effects of pseudolaric acid B (PAB) on the proliferation and apoptosis of HEp-2 cells. Methods Cell grouping and treatment: cells were treated with 0, 0.5, 1, 2, 4, 8 and 16 μmol/L PAB for 24, 48 and 72 h respectively; MTT assay was used to detect cell viability; flow cytometry was used to detect apoptosis; The expression of Bcl-2, Bax and caspase-3 protein and mRNA was detected by Western blot and qPCR. The expression of PARP and c-PARP was detected by immunohistochemistry. Results PAB inhibited HEp-2 proliferation in a time-concentration dependent manner. Compared with the control group, the apoptosis rate of HEp-2 cells in 4 μmol/L and 8 μmol/L PAB groups was significantly increased(P＜0.01). Compared with the control group, the expression of Bcl-2 and PARP in HEp-2 cells of 4 μmol/L and 8 μmol/L PAB groups were significantly decreased(P＜0.05), and the expression of Bax, caspase-3 and c-PARP was significantly increased(P＜0.05). Conclusions PAB can activate the mitochondrial apoptosis pathway thus induce apoptosis of HEp-2 cells and inhibit cell proliferation.

Key words: pseudolaric acid B, laryngeal cancer, mitochondrial apoptosis, mechanism