OBJECTIVEThe aim of this study was to observe the suppressive effect of bortezomib alone and the synergistic suppressive effect of bortezomib and adriamycin on the proliferation of the cell line Jurkat cells, and to discuss the mechanism of apoptosis induced by bortezomib.

METHODSThe suppressive effect of bortezomib and adriamycin on the proliferation of Jurkat cells in vitro was detected by MTT colorimetry, and the morphology of the cells was examined by histology. The cell apoptosis was measured by flow cytometry with Annexin V/PI staining and cell cycle analysis. The effect of bortezomib and adriamycin on the expression levels of caspase-3, caspase-8 and PARP were measured by Nestern blot.

RESULTSThe proliferation of Jurkat cells was significantly inhibited by bortezomib treatment (between 10 - 320 ng/ml) for 24 h, 48 h and 72 h, and the growing inhibition ratio showed a positive correlation with the drug concentration (r(24 h) = 0.900, P < 0.01; r(48 h) = 0.849, P < 0.01; r(72 h) = 0.679, P < 0.01), in a concentration-dependent manner. The IC(50) of Jurkat cells treated with bortezomib in a dose of 10 - 320 ng/ml was 137.64 +/- 6.82 ng/ml, but the IC(50) of Jurkat cells treated with bortezomib combined with adriamycin (125 ng/ml) for 24 h was significantly decreased to 20.44 +/- 2.85 ng/ml. The apoptosis rate had a positive correlation with the concentration of bortezomib (P < 0.01). After the Jurkat cells were treated with bortezomib, apparent shear bands of caspase-8, caspase-3 and PARP proteins were observed.

CONCLUSIONThere is an effect of Bortezomib to induce apoptosis in Jurkat cells, and the extrinsic pathway is one of the apoptosis-inducing mechanisms. There is a synergistic suppressive effect of the combination of bortezomib and adriamycin on the proliferation of Jurkat cells and enhances their chemosensitivity.