OBJECTIVETo investigate the anticancer effects and molecular mechanism of deguelin on human Burkitt's lymphoma Daudi cells in vitro and compare the cytotoxicity of deguelin on Daudi cells and human peripheral blood monocular cells (HPBMC).

METHODSThe effects of deguelin on the growth of Daudi cells were studied by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5 diphenyl-2H-tetrazolium (MTT) assay. Apoptosis was assessed through Hoechst 33258 staining and annexin V/PI double-labeled cytometry. The effect of deguelin on the cell cycle of Daudi cells was studied by propidium iodide method. The expressions of cyclin D1 and pRb were checked by Western blot.

RESULTSThe proliferation of Daudi cells was decreased in deguelin-treated group with a 24 h IC50 value of 51. 55 nmol/L. Deguelin induced Daudi cells apoptosis in a time- and dose-dependent manner. Daudi cells treated with deguelin showed an increase of G0/G1 phase and decrease of S phase. The Daudi cells treated with 0, 5, 10, 20, 40 nmol/L deguelin for 24 h, showed an increased Go/G, phase from 37.34% to 56.56% , whereas decreased S phase from 37.72% to 21.36%, respectively. PBMC was less sensitive to the cytotoxic effect of deguelin than Daudi cells. The expression of cyclin D1 and pRb protein were decreased in Daudi cells treated with deguelin.

CONCLUSIONDeguelin can inhibit the proliferation of Daudi cells by regulating the cell cycle that arrest cells at G0/G1 phase and inducing apoptosis. Moreover, deguelin demonstrats low toxicity in PBMC but selectively induces apoptosis of Daudi cells. The antitumor effects of deguelin may be related to down-regulation of the expression of cyclin D1 and pRb protein.