Cystatin SN inhibits auranofin-induced cell death by autophagic induction and ROS regulation via glutathione reductase activity in colorectal cancer.
Cystatin SN inhibits auranofin-induced cell death by autophagic induction and ROS regulation via glutathione reductase activity in colorectal cancer.
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DOI：
10.1038/cddis.2017.100
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发表时间：
2017-03-16
影响因子：
9
通讯作者：
Lee HG
中科院分区：
文献类型：
--
作者：
Oh BM;Lee SJ;Cho HJ;Park YS;Kim JT;Yoon SR;Lee SC;Lim JS;Kim BY;Choe YK;Lee HG
半胱氨酸蛋白酶抑制剂SN（Cystatin SN，CST1）是属于半胱氨酸蛋白酶抑制剂超家族的特异性抑制剂，其控制半胱氨酸蛋白酶如组织蛋白酶的蛋白水解活性。我们以前的研究表明，高表达的CST1增强了大肠癌的转移和侵袭性。最近，金诺芬（AF），一种含金（I）的硫氧还蛋白还原酶1（TrxR1）抑制剂，已被临床用于治疗类风湿性关节炎。AF是一种蛋白酶体相关的去泛素化酶抑制剂，可作为抗肿瘤药物。在这项研究中，我们研究了CST1表达是否诱导自噬和肿瘤细胞存活。我们还研究了AF作为结直肠癌（CRC）细胞中的抗肿瘤剂的治疗效果。我们发现，表达高水平的CST1的CRC细胞经历增加的自噬，并表现出化疗耐AF诱导的细胞死亡，而那些表达低水平的CST1是敏感的AF。我们还观察到，敲低CST1在高CST1 CRC细胞使用CST1特异性小干扰RNA衰减自噬激活和恢复AF诱导的细胞死亡率。相反，CST1的过表达增加了表达低水平CST1的细胞的自噬和活力。有趣的是，CST1的高表达通过抑制细胞内活性氧（ROS）的产生来减弱AF诱导的细胞死亡，如ROS产生的阻断逆转了CRC细胞中AF诱导的细胞死亡的事实所证明的。此外，上调CST1表达增加了细胞谷胱甘肽还原酶（GR）活性，降低了细胞的氧化还原状态，并诱导AF处理的CRC细胞自噬。这些结果表明，CST1的高表达可能参与自噬诱导，并通过调节GR活性抑制ROS的产生，保护AF诱导的细胞死亡。
Cystatin SN (CST1) is a specific inhibitor belonging to the cystatin superfamily that controls the proteolytic activities of cysteine proteases such as cathepsins. Our previous study showed that high CST1 expression enhances tumor metastasis and invasiveness in colorectal cancer. Recently, auranofin (AF), a gold(I)-containing thioredoxin reductase 1 (TrxR1) inhibitor, has been used clinically to treat rheumatoid arthritis. AF is a proteasome-associated deubiquitinase inhibitor and can act as an anti-tumor agent. In this study, we investigated whether CST1 expression induces autophagy and tumor cell survival. We also investigated the therapeutic effects of AF as an anti-tumor agent in colorectal cancer (CRC) cells. We found that CRC cells expressing high levels of CST1 undergo increased autophagy and exhibit chemotherapeutic resistance to AF-induced cell death, while those expressing low levels of CST1 are sensitive to AF. We also observed that knockdown of CST1 in high-CST1 CRC cells using CST1-specific small interfering RNAs attenuated autophagic activation and restored AF-induced cell mortality. Conversely, the overexpression of CST1 increased autophagy and viability in cells expressing low levels of CST1. Interestingly, high expression of CST1 attenuates AF-induced cell death by inhibiting intracellular reactive oxygen species (ROS) generation, as demonstrated by the fact that the blockage of ROS production reversed AF-induced cell death in CRC cells. In addition, upregulation of CST1 expression increased cellular glutathione reductase (GR) activity, reducing the cellular redox state and inducing autophagy in AF-treated CRC cells. These results suggest that high CST1 expression may be involved in autophagic induction and protects from AF-induced cell death by inhibition of ROS generation through the regulation of GR activity.