School of Pharmacy, National Taiwan University, Taipei, Taiwan.
Br J Pharmacol. 2010 Aug;160(7):1677-89. doi: 10.1111/j.1476-5381.2010.00832.x.
The c-Jun N-terminal kinase (JNK) and tubulin are, frequently, targets for developing anti-cancer drugs. A major obstacle to successful development is P-glycoprotein (P-gp)-mediated resistance. Here, we have assessed a compound that inhibited growth of cancer cells, for effects on JNK and tubulin and as a substrate for P-gp.
Several pharmacological and biochemical assays were used to characterize signalling pathways of 2-phenyl-5-(pyrrolidin-1-yl)-1-(3,4,5-trimethoxybenzyl)-1H-benzimidazole (PPTMB), a benzimidazole analogue, in prostate cancer cells.
PPTMB inhibited proliferation of several human prostate cancer cell lines. It displayed similar activity against a P-gp-rich cell line, indicating that PPTMB was not a substrate for P-gp. PPTMB induced G2/M arrest of the cell cycle and subsequent apoptosis, using flow cytometry. Tubulin polymerization assays and Western blot analysis showed that PPTMB directly acted on tubulin and caused disruption of microtubule dynamics, inducing mitotic arrest and sustained high levels of cyclin B1 expression and Cdk1 activation. Subsequently, mitochondria-related apoptotic cascades were induced, including Bcl-2 and Bcl-xL phosphorylation, Mcl-1 down-regulation, truncated Bad formation and activation of caspase-9 and -3. PPTMB stimulated JNK phosphorylation at Thr(183)/Tyr(185). SP600125, a specific JNK inhibitor, significantly inhibited apoptotic signalling, indicating that JNK plays a key role in PPTMB action. PPTMB showed a 10-fold higher potency against prostate cancer cells than normal prostate cells.
PPTMB is an effective anti-cancer agent. It disrupted microtubule dynamics, leading to mitotic arrest of the cell cycle and JNK activation, which in turn stimulated the mitochondria-related apoptotic cascades in prostate cancer cells.
c-Jun N-末端激酶（JNK）和微管蛋白经常是开发抗癌药物的靶点。成功开发的主要障碍是 P-糖蛋白（P-gp）介导的耐药性。在这里，我们评估了一种抑制癌细胞生长的化合物，以研究其对 JNK 和微管蛋白的作用以及作为 P-gp 底物的作用。
使用几种药理学和生化测定方法来研究苯并咪唑类似物 2-苯基-5-（吡咯烷-1-基）-1-（3,4,5-三甲氧基苄基）-1H-苯并咪唑（PPTMB）在前列腺癌细胞中的信号通路。
PPTMB 抑制了几种人前列腺癌细胞系的增殖。它对 P-gp 丰富的细胞系显示出相似的活性，表明 PPTMB 不是 P-gp 的底物。PPTMB 通过流式细胞术诱导细胞周期 G2/M 期阻滞和随后的细胞凋亡。微管蛋白聚合实验和 Western blot 分析表明，PPTMB 直接作用于微管蛋白并导致微管动力学破坏，诱导有丝分裂阻滞和持续高水平的细胞周期蛋白 B1 表达和 Cdk1 激活。随后，诱导了与线粒体相关的凋亡级联反应，包括 Bcl-2 和 Bcl-xL 磷酸化、Mcl-1 下调、截断的 Bad 形成以及 caspase-9 和 caspase-3 的激活。PPTMB 刺激 JNK 在 Thr(183)/Tyr(185)处磷酸化。特异性 JNK 抑制剂 SP600125 显著抑制了凋亡信号，表明 JNK 在 PPTMB 作用中起关键作用。PPTMB 对前列腺癌细胞的活性比正常前列腺细胞高 10 倍。
PPTMB 是一种有效的抗癌药物。它破坏了微管蛋白动力学，导致细胞周期有丝分裂阻滞和 JNK 激活，进而刺激了前列腺癌细胞中线粒体相关的凋亡级联反应。
