Mechanisms of proteasome inhibitor PS-341-induced G(2)-M-phase arrest and apoptosis in human non-small cell lung cancer cell lines.
Mechanisms of proteasome inhibitor PS-341-induced G(2)-M-phase arrest and apoptosis in human non-small cell lung cancer cell lines.
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发表时间：
2003-03
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通讯作者：
Y. Ling;L. Liebes;Jian-Dong Jiang;J. Holland;P. Elliott;J. Adams;F. Muggia;R. Perez-soler
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作者：
Y. Ling;L. Liebes;Jian-Dong Jiang;J. Holland;P. Elliott;J. Adams;F. Muggia;R. Perez-soler
目的PS-341是一种新型的二肽硼酸蛋白酶体抑制剂，具有体内外抗肿瘤活性，诱导细胞凋亡的机制不明。实验设计以人非小细胞肺癌细胞系为研究对象，研究PS-341对细胞增殖、细胞周期进程和诱导细胞凋亡的影响。结果PS-341对H460细胞的杀伤作用是蛋白酶体抑制剂MG-132和PSI的38~360倍。PS-341对P53功能的细胞毒作用不同：H322细胞(P53突变体)的敏感性是H460细胞(P53野生型)的6倍，H358细胞(P53基因缺失)是H460细胞(P53野生型)的1.6倍。H460细胞呈浓度和时间依赖性的细胞周期G(2)-M期阻滞，对微管聚合或解聚无直接影响。PS-341作用于H460细胞后，P53蛋白稳定，p21(CIP/WAF-1)和MDM2表达上调，细胞周期蛋白B和细胞周期蛋白A表达增加，细胞周期蛋白B和细胞周期蛋白A激活。MDM2仅在H460细胞中被诱导，而在H322和H358细胞中发现G(2)-M期停滞，p21(CIP/WAF-1)诱导，细胞周期蛋白B1增加。G(2)-M期细胞在无药物培养液中通过激活caspase-3和裂解聚(ADP-核糖)聚合酶来验证细胞对凋亡的承诺。结论PS-341诱导的细胞G(2)-M期阻滞可能与抑制细胞周期调节因子降解有关，p21(CIP/WAF-1)表达上调可能通过P53依赖和/或非依赖途径实现。由此导致的细胞周期进程的障碍要么导致生长抑制，要么导致凋亡途径的启动。
PURPOSE PS-341 is a novel dipeptide boronic acid proteasome inhibitor with in vitro and in vivo antitumor activity that induces mechanisms of apoptosis by unknown mechanisms. EXPERIMENTAL DESIGN Human non-small cell lung cancer cell lines were used to investigate effects PS-341 on cell proliferation, cell cycle progression, and the induction of apoptosis. RESULTS PS-341 was 38-360-fold more cytotoxic against H460 cells when compared with the proteasome inhibitors MG-132 and PSI. Differential PS-341 cytotoxic effects were found with respect to P53 function: H322 cells (p53 mutant) were 6-fold less sensitive as compared with H460 cells (p53 wild type); and H358 cells (p53 null) were 1.6-fold more sensitive as compared with H460 cells (p53 wild type). A concentration- and time-dependent cell cycle blockade at G(2)-M phase was seen for H460 cells without any direct effects on microtubule polymerization or depolymerization. PS-341 exposure in H460 cells led to stabilization of p53, induction of p21(cip/waf-1) and MDM2 expression, an increase in cyclin B and cyclin A, and the activation of cyclin B and cyclin A kinases. MDM2 induction was found only in H460 cells, whereas in H322 and H358 cells, G(2)-M-phase arrest, p21(cip/waf-1) induction, and an increase in cyclin B1 were found. The commitment of G(2)-M-phase cells to apoptosis was verified by the activation of caspase-3 and cleavage of poly(ADP-ribose) polymerase in drug-free medium. CONCLUSIONS Our data suggest that the PS-341-induced G(2)-M-phase arrest may be associated with the inhibition of degradation of cell cycle regulators and that the up-regulation of p21(cip/waf-1) expression may be via p53-dependent and/or -independent pathways. The resulting disturbance of cell cycle progression leads either to growth inhibition or to the initiation of apoptotic pathways.