Wang Yulong, Ou Li, Li Xirong, Zheng Tingyu, Zhu Wei-Pei, Li Ping, Wu Lijun, Zhao Tianlan
Department of Plastic and Cosmetic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, China.
Department of Burn and Plastic Surgery, Jining First People's Hospital, Jining, China.
Cell Death Discov. 2022 Aug 3;8(1):347. doi: 10.1038/s41420-022-01148-5.
RNA polymerase mitochondrial (POLRMT) expression and the potential biological functions in skin squamous cell carcinoma (SCC) were explored. We showed that POLRMT is significantly elevated in skin SCC. Genetic depletion of POLRMT, using shRNA-induced knockdown or CRISPR/Cas9-mediated knockout (KO), resulted in profound anti-skin SCC cell activity. In patient-derived primary skin SCC cells or immortalized lines (A431 and SCC-9), POLRMT shRNA or KO potently suppressed mitochondrial DNA (mtDNA) transcription and suppressed cell viability, proliferation and migration. POLRMT shRNA or KO impaired mitochondrial functions in different skin SCC cells, leading to production of ROS (reactive oxygen species), depolarization of mitochondria and depletion of ATP. Moreover, mitochondrial apoptosis cascade was induced in POLRMT-depleted skin SCC cells. IMT1, a POLRMT inhibitor, largely inhibited proliferation and migration, while inducing depolarization of mitochondria and apoptosis in primary skin SCC cells. Contrarily, ectopic overexpression of POLRMT increased mtDNA transcription and augmented skin SCC cell growth. Importantly, POLRMT shRNA adeno-associated virus injection robustly hindered growth of the subcutaneous A431 xenografts in mice. In the POLRMT shRNA virus-treated A431 xenograft tissues, POLRMT depletion, mtDNA transcription inhibition, cell apoptosis, lipid peroxidation and ATP depletion were detected. Together, overexpressed POLRMT increases mtDNA transcription and promotes skin SCC growth.
探讨了线粒体RNA聚合酶（POLRMT）在皮肤鳞状细胞癌（SCC）中的表达及其潜在生物学功能。我们发现POLRMT在皮肤SCC中显著升高。使用shRNA诱导的敲低或CRISPR/Cas9介导的敲除（KO）对POLRMT进行基因敲减，可产生显著的抗皮肤SCC细胞活性。在患者来源的原发性皮肤SCC细胞或永生化细胞系（A431和SCC-9）中，POLRMT shRNA或KO可有效抑制线粒体DNA（mtDNA）转录，并抑制细胞活力、增殖和迁移。POLRMT shRNA或KO会损害不同皮肤SCC细胞中的线粒体功能，导致活性氧（ROS）产生、线粒体去极化和ATP耗竭。此外，POLRMT敲减的皮肤SCC细胞中会诱导线粒体凋亡级联反应。POLRMT抑制剂IMT1在很大程度上抑制了原发性皮肤SCC细胞的增殖和迁移，同时诱导线粒体去极化和凋亡。相反，POLRMT的异位过表达增加了mtDNA转录并增强了皮肤SCC细胞的生长。重要的是，POLRMT shRNA腺相关病毒注射可强烈抑制小鼠皮下A431异种移植瘤的生长。在POLRMT shRNA病毒处理的A431异种移植瘤组织中，检测到POLRMT敲减、mtDNA转录抑制、细胞凋亡、脂质过氧化和ATP耗竭。总之，过表达的POLRMT增加mtDNA转录并促进皮肤SCC生长。
