PDF(Pubmed)
Abstract：
Mitochondria play a multifaceted role in supporting bladder cancer progression. Translocase of inner mitochondrial membrane 44 (TIMM44) is essential for maintaining function and integrity of mitochondria. We here tested the potential effect of MB-10 (MitoBloCK-10), a first-in-class TIMM44 blocker, against bladder cancer cells. TIMM44 mRNA and protein expression is significantly elevated in both human bladder cancer tissues and cells. In both patient-derived primary bladder cancer cells and immortalized (T24) cell line, MB-10 exerted potent anti-cancer activity and inhibited cell viability, proliferation and motility. The TIMM44 blocker induced apoptosis and cell cycle arrest in bladder cancer cells, but failed to provoke cytotoxicity in primary bladder epithelial cells. MB-10 disrupted mitochondrial functions in bladder cancer cells, causing mitochondrial depolarization, oxidative stress and ATP reduction. Whereas exogenously-added ATP and the antioxidant N-Acetyl Cysteine mitigated MB-10-induced cytotoxicity of bladder cancer cells. Genetic depletion of TIMM44 through CRISPR-Cas9 method also induced robust anti-bladder cancer cell activity and MB-10 had no effect in TIMM44-depleted cancer cells. Contrarily, ectopic overexpression of TIMM44 using a lentiviral construct augmented proliferation and motility of primary bladder cancer cells. TIMM44 is important for Akt-mammalian target of rapamycin (mTOR) activation. In primary bladder cancer cells, Akt-S6K1 phosphorylation was decreased by MB-10 treatment or TIMM44 depletion, but enhanced after ectopic TIMM44 overexpression. In vivo, intraperitoneal injection of MB-10 impeded bladder cancer xenograft growth in nude mice. Oxidative stress, ATP reduction, Akt-S6K1 inhibition and apoptosis were detected in MB-10-treated xenograft tissues. Moreover, genetic depletion of TIMM44 also arrested bladder cancer xenograft growth in nude mice, leading to oxidative stress, ATP reduction and Akt-S6K1 inhibition in xenograft tissues. Together, targeting overexpressed TIMM44 by MB-10 significantly inhibits bladder cancer cell growth in vitro and in vivo.
摘要：
线粒体在支持膀胱癌进展中起着多方面的作用。线粒体内膜44（TIMM44）的转位酶对于维持线粒体的功能和完整性至关重要。我们在这里测试了MB-10(MitoBloCK-10)的潜在作用，一流的TIMM44阻断剂，对抗膀胱癌细胞。TIMM44mRNA和蛋白质表达在人膀胱癌组织和细胞中均显着升高。在患者来源的原发性膀胱癌细胞和永生化（T24）细胞系中，MB-10发挥有效的抗癌活性并抑制细胞活力，增殖和运动。TIMM44阻断剂诱导膀胱癌细胞凋亡和细胞周期阻滞，但未能引起原代膀胱上皮细胞的细胞毒性。MB-10破坏了膀胱癌细胞的线粒体功能，导致线粒体去极化，氧化应激和ATP减少。而外源添加的ATP和抗氧化剂N-乙酰半胱氨酸减轻了MB-10诱导的膀胱癌细胞的细胞毒性。通过CRISPR-Cas9方法的TIMM44的遗传消耗也诱导了强大的抗膀胱癌细胞活性，而MB-10在TIMM44耗尽的癌细胞中没有作用。相反，使用慢病毒构建体对TIMM44的异位过表达增强了原发性膀胱癌细胞的增殖和运动。TIMM44对于Akt-哺乳动物雷帕霉素靶蛋白(mTOR)激活是重要的。在原发性膀胱癌细胞中，Akt-S6K1磷酸化通过MB-10处理或TIMM44去除减少，但在异位TIMM44过表达后增强。在体内,腹膜内注射MB-10会阻碍裸鼠膀胱癌异种移植物的生长。氧化应激,ATP减少，在MB-10处理的异种移植组织中检测到Akt-S6K1抑制和凋亡。此外，TIMM44的遗传耗竭也阻止了裸鼠膀胱癌异种移植的生长，导致氧化应激，异种移植组织中的ATP减少和Akt-S6K1抑制。一起,MB-10靶向过表达的TIMM44在体外和体内显着抑制膀胱癌细胞的生长。
