The effect of cell killing by ABT-737 synergized with docetaxel in human prostate cancer PC-3 cells / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the synergistical killing effect of docetaxel combined with ABT-737 on human prostate cancer cell line PC-3 by inducing apoptosis and further to determine the mechanism underlying such effect.</p><p><b>METHODS</b>PC-3 cells were treated with various concentrations of docetaxel or (and) ABT-737. Cell viability was determined using MTT assay. Apoptosis was assessed by fluorescence microscopy analysis of cells with condensed and segmented nuclei following staining with 4',6-diamidino-2-phenylindole (DAPI). Cellular DNA was stained with propidium iodide and flow cytometric analysis was performed to analyze the cell cycle distribution. Bcl-2, Bax, Bcl-xL and Mcl-1 protein changes were detected by Western blot. The activity of caspase-3 was measured using a colorimetric assay.</p><p><b>RESULTS</b>Docetaxel (20 nmol/L) combination with ABT-737 (400 nmol/L) for 48 hours, the cell viability was decreased to 19.7% ± 3.2% to compare with 44.2% ± 4.4% (t = 4.45) of docetaxel and 93.2% ± 1.8% of ABT-737 separately and there was a synergistic effect between the two drugs (CI = 0.8). Apoptosis rate of the combination group was higher than other two drugs. Docetaxel increased the cell number arrested in G(2)/M phase compared with control group (P < 0.05), but the combination treatment resulted in a significant arrest in the G(0)/G(1) phase. The combination treatment could significantly reduced the Bcl-2, Bcl-xL and Mcl-1 expression (F = 369.53, 57.89 and 32.77, all P < 0.05) and enhanced the activity of caspase-3 (419.7% ± 15.6%) (F = 207.33, P < 0.05).</p><p><b>CONCLUSIONS</b>The combination of ABT-737 with docetaxel can synergistically inhibit the proliferation of PC-3 cells through inducing apoptosis, which may be associated with cell cycle arrest, down-regulation of Bcl-2, Bcl-xL and Mcl-1 expression and activation of caspase-3.</p>

The effect of cell killing and apoptosis by human herpes simplex virus- thymidine kinase/ganciclovir system combined with allitride in BIU87 cells / 中华外科杂志

<p><b>OBJECTIVE</b>To study the killing effect of human herpes simplex virus-thymidine kinase/ganciclovir (HSV-TK/GCV) system combined with allitride and the possible apoptosis mechanism in BIU87 cells.</p><p><b>METHODS</b>The cytotoxicity after combination were estimated by theamine blue tetrazolium bromide (MTT). The morphological changes were observed with inverted microscope and in-situ cell apoptosis detection kit. Changes of apoptosis rate and cell cycle were assessed by flow cytometry. B-cell lymphoma-2 (bcl-2), bax, caspase-3 (cysteine aspartate specific proteinase) mRNA changes were detected by reverse transcriptase polymerase chain reaction, and caspase-3 activity was estimated with colorimetry.</p><p><b>RESULTS</b>For combination group, the cell killing rate was raised to 72.50% to compare with 35.00% of GCV and 37.00% of allitride separately and there was a synergistic effect between these two drugs. The cell apoptosis was induced in all three groups and for the combination group the time of S-phase and G(2)-phase arrest were earlier than other two groups. Both drugs could inhibit the expression of bcl-2 and promote the expression and activity of caspase-3.</p><p><b>CONCLUSIONS</b>The combination of HSV-TK/GCV system with allitride can inhibit the proliferation of BIU87 cells congenerously through apoptosis, which may be correlated with S- and G(2)-phase arrest, down-regulation of bcl-2 and increased caspase-3 expression and its activity.</p>