OBJECTIVETo investigate the effects of gossypol acetate on proliferation and apoptosis in Raji lymphoblastoid cells and explore the possible mechanism.

METHODSTrypan blue staining and ethyl thiazolyl diphenyl-tetrazolium bromide (MTT) assay were performed to measure the effect of gossypol acetate on the growth of Raji cells. The morphologic changes were observed with Wright's staining assay. Apoptosis was identified by agarose-gel electrophoresis and annexin V-FITC marked flow cytometry (FCM) analysis. The distribution of cell cycle, apoptosis rate, and Bcl-2 protein expression were analyzed by FCM. Caspase-3 activity was detected by colorimetric assay.

RESULTSGossypol acetate inhibited proliferation and induced apoptosis of Raji cells at concentration higher than 5 micromol/L. The effects were both dose- and time- dependent. Cycle analysis indicated the alteration of cell cycle and G0/G1 arrest. The activation of Caspase-3 was observed by colorimetric assay. The results of flow cytometry showed that the down-regulation of Bcl-2 protein expression and the activation of Caspase-3 seemed to occur simultaneously.

CONCLUSIONGossypol acetate can inhibit the growth of Raji cells and induce their apoptosis. The mechanism may be related to the alteration of cell cycle and the down-regulation of Bcl-2 protein expression.