【摘要】 目的:探讨环氧合酶-2(COX-2)抑制剂塞来昔布(celecoxib)促进酪氨酸激酶抑制剂STI571的抗白血病效应及其机制。方法:以不同浓度的celecoxib与STI571组合孵育K562细胞,光镜、荧光显微镜观察细胞形态,MTT比色法观察两者对细胞的生长抑制情况,流式细胞术作DNA倍体分析及细胞凋亡线粒体流式检测,半定量RT-PCR法分析相关基因的表达。结果:(1)Celecoxib可促进STI571抑制白血病细胞增殖的能力,0.25μmol/LSTI571与40.0、60.0μmol/L的celecoxib联用抑制率分别为76.1%±1.6%、91.5%±0.4%,明显高于单药组60.0%±2.0%(0.25μmol/L STI571)、34.7%±0.5%(40.0μmol/L celecoxib)、49.8%±1.8%(60.0μmol/L cele-coxib)(P<0.05)。(2)单用celecoxib时未检测到细胞凋亡发生,但与STI571联用时可显著增强STI571诱导凋亡的能力,表现为明显凋亡形态学改变,亚G1期细胞及线粒体凋亡百分率显著增高,其中0.25μmol/L STI571与40μmol/L celecoxib联用时分别为20.6%±3.6%、31.3%±4.3%,高于STI571单药组(分别为3.0%±0.6%、3.2%±0.4%)(P<0.05)。(3)单用celecoxib、STI571对COX-2表达没有影响,而联用则COX-2显著下调(P<0.05),但联用及单用对VEGF表达均没有影响(P>0.05)。结论:单用celecoxib仅抑制K562细胞增殖,而联用STI571可明显降低K562细胞对STI571的效应阈值,促进STI571诱导的增殖抑制和凋亡。更多还原

【Abstract】 AIM: To investigate whether celecoxib,a cyclooxygenase-2（COX-2） inhibitor,potentiates the anti-leukemia activity of STI571 in K562 cells.METHODS: K562 cells were treated with STI571,celecoxib or combination of both at different concentrations in suspension culture.Cell proliferation was documented by MTT assay,and cell apoptosis was determined by flow cytometry and morphology.Meanwhile,RT-PCR was applied to analyze the probable mechanism underlying the effects of the drugs.RESULTS: The combination of STI571 and celecoxib dramatically suppressed the proliferation of K562 cells,in which 0.25 μmol/L STI571 and 40.0 μmol/L celecoxib enhanced the inhibiting rate to 76.1%±1.6%.Furthermore,the combining administration of drugs significantly promoted the apoptosis induced by STI571,which showed characteristic changes of morphologic features and increase in sub-G₁ cells.By using RT-PCR technique,the expression of COX-2 had no decline by single administration of celecoxib or STI571.However,a progressive down-regulation was caused by coadministration of two drugs.In contrast with COX-2,the expression of VEGF had no changes at any time.CONCLUSION: The administration of celecoxib alone only inhibits the proliferation of K562 cells.Combination treatment with STI571 and celecoxib promotes the apoptosis induced by STI571.更多还原