Department of Pharmacology, Ernst Moritz Arndt University, Friedrich Loefflerstr. 23d, 17487 Greifswald, Germany.
Biochem Pharmacol. 2010 Nov 15;80(10):1466-77. doi: 10.1016/j.bcp.2010.07.036. Epub 2010 Aug 13.
The cysteine protease cathepsin B acts as a key player in apoptosis. Cathepsin B-mediated cell death is induced by various stimuli such as ischemia, bile acids or TNFα. Whether cathepsin B can be influenced by anticancer drugs, however, has not been studied in detail. Here, we describe the modulation of doxorubicin-induced cell death by silencing of cathepsin B expression. Previously, it was shown that doxorubicin, in contrast to other drugs, selectively regulates expression and activity of cathepsin B. Selective silencing of cathepsin B by siRNA or the cathepsin B specific inhibitor CA074Me modified doxorubicin-mediated cell death in Hela tumor cells. Both Caspase 3 activation and PARP cleavage were significantly reduced in cells lacking cathepsin B. Moreover, mitochondrial membrane permeabilization as well as the release of cytochrome C and AIF from mitochondria into cytosol induced by doxorubicin were significantly diminished in cathepsin B suppressed cells. In addition, doxorubicin associated down-regulation of XIAP was not observed in cathepsin B silenced cells. Lack of cathepsin B significantly modified cell cycle regulatory proteins such as cdk1, Wee1 and p21 without significant changes in G(1), S or G(2)M cell cycle phases maybe indicating further cell cycle independent actions of these proteins. Consequently, cell viability following doxorubicin was significantly elevated in cells with cathepsin B silencing. In summary, our data strongly suggest a role of cathepsin B in doxorubicin-induced cell death. Therefore, increased expression of cathepsin B in various types of cancer can modify susceptibility towards doxorubicin.
半胱氨酸蛋白酶 cathepsin B 作为细胞凋亡的关键因子发挥作用。Cathepsin B 介导的细胞死亡是由各种刺激诱导的，如缺血、胆汁酸或 TNFα。然而，cathepsin B 是否可以被抗癌药物影响尚未被详细研究。在这里，我们描述了通过沉默 cathepsin B 表达来调节阿霉素诱导的细胞死亡。先前已经表明，与其他药物相比，阿霉素选择性地调节 cathepsin B 的表达和活性。通过 siRNA 或 cathepsin B 特异性抑制剂 CA074Me 选择性沉默 cathepsin B 可修饰 Hela 肿瘤细胞中的阿霉素介导的细胞死亡。在缺乏 cathepsin B 的细胞中，Caspase 3 激活和 PARP 切割明显减少。此外，阿霉素诱导的线粒体膜通透性以及细胞色素 C 和 AIF 从线粒体向细胞质的释放，在 cathepsin B 被抑制的细胞中显著减少。此外，在 cathepsin B 沉默的细胞中未观察到阿霉素相关的 XIAP 下调。缺乏 cathepsin B 显著修饰细胞周期调节蛋白，如 cdk1、Wee1 和 p21，而 G1、S 或 G2M 细胞周期阶段没有明显变化，这可能表明这些蛋白具有进一步的细胞周期非依赖性作用。因此，在 cathepsin B 沉默的细胞中，阿霉素后的细胞活力显著升高。总之，我们的数据强烈表明 cathepsin B 在阿霉素诱导的细胞死亡中起作用。因此，各种类型的癌症中 cathepsin B 的高表达可以改变对阿霉素的敏感性。
