A Study On The Molecular Mechanism And Apoptosis Of HL-60 Cells Induced By Paclitaxel

Paclitaxel has a high cytotoxic effect. Its target is cellular skeleton-microtubules. Paclitaxel can effect polymerization and de-polymerization of microtubules, and inhibit mitosis program. Lots of multinucleate cells appeared, cells are arrested in G0 or G2/M phase. Paclitaxel-inducing cells apoptosis correlate with express of apoptosis factor and activation of apoptosis signal pathway. There is not a clear theory to illuminate that which factors or signal pathways participate in this course. At present, researcher results show different apoptosis mechanism induced by paclitaxel due to different tumor tissue, cell category or paclitaxel dose. Mechanism of paclitaxel-inducing apoptosis is one of hot stadies on tumor treatment.Now paclitaxel is broad applied to treatment on many tumors, including breast cancer, ovarian cancer, cystic cancer, esophageal cancer, no small lung cancer, gastric cancer, bladder cancer, leukaemia and marrow sarcoma. Owing to morrow inhibition appears after long-time or excessive dose effect of paclitaxel, clinic study on anti-leukaemia action of paclitaxel is limited. So, there is a few clinic research on leukaemia by paclitaxel. Recently, leukaemia cells apoptosis induced by paclitaxel focus on study in vitro, many research results show that leukaemia cells have different response to paclitaxel according to cell category.This experiment study the cell cycle-arresting and apoptosis-inducing effect of paclitaxel on HL-60 cells, and research the molecular mechanism of paclitaxel-inducting apoptosis on HL-60 including Bcl-2 gene family, so as to offer the experimental basis to leukemic clinic cure by paclitaxel and enhance HL-60 sensibility to paclitaxel cytotoxic effect.HL-60 cells in culture medium were treated with different concentrations of paclitaxel. Morphology of cell apoptosis was observed by optical microscopes. Cell apoptotic-rate was detected by flow cytometry (FCM). DNA gel electrophoresis were used to demonstrate DNA fragmentations. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect mRNA expression. Protein levels were studied by western-blot technique.Resulte:1. Paclitaxel can effect on HL-60 cells growth and induce apoptosis in vitro. The role of paclitaxel-inducing apoptosis is marked dose-depend.2. This stady shows that 10-7mol/L paclitaxel can induce late phase apoptosis in HL-60 cells after exposued 24h.3. we can observe marked downregulate of Bcl-2 gene and up-regulate of Bad gene after exposure to various concentrations paclitaxel for 24h. But the expression of Bax gene and Bcl-xl gene are not changed in HL-60 cells.These evidences show Bcl-2 gene family...