Cisplatin resistance is one of the major causes of treatment failure in head and neck squamous cell carcinoma (HNSCC). There is an urgent need to uncover the underlying mechanism for developing effective treatment strategies. A quantitative proteomics assay was used to identify differential proteins in cisplatin-resistant cells. Mitochondrial topoisomerase I (TOP1MT) localization was determined using laser confocal microscopy and nucleocytoplasmic separation assay. Chromatin immunoprecipitation sequencing, dual-luciferase reporter assay, and RNA immunoprecipitation were used to identify the interaction between pseudogenes, miRNAs, and real genes. In vivo experiments verified the interaction between TOP1MT and pseudogenes on cisplatin resistance. TOP1MT was identified as a driving factor of cisplatin resistance in vitro, in vivo, and in HNSCC patients. Moreover, TOP1MT exceptionally translocated to the nucleus in cisplatin-resistant HNSCC cells in a signal peptide–dependent manner. Nuclear TOP1MT (nTOP1MT) transcriptionally regulated the mitochondrial functional pseudogene MTATP6P1, which bound to miR-137 and miR-491-5p as a competing endogenous RNA (ceRNA) and promoted the expression of MTATP6. An increase in MTATP6 enhanced mitochondrial oxidative phosphorylation (OXPHOS), which conferred cisplatin resistance in HNSCC. Our findings revealed that nTOP1MT transcriptionally activated MTAPT6P1 and increased MTATP6 expression via ceRNA, which facilitated OXPHOS and cisplatin resistance. These results provide novel insight for overcoming cisplatin resistance in HNSCC.

中文翻译：

---

核 TOP1MT 通过 HNSCC 中的假基因赋予顺铂耐药


顺铂耐药是头颈部鳞状细胞癌 （HNSCC） 治疗失败的主要原因之一。迫切需要揭示制定有效治疗策略的潜在机制。采用定量蛋白质组学测定法鉴定顺铂耐药细胞中的差异蛋白。使用激光共聚焦显微镜和核质分离测定法测定线粒体拓扑异构酶 I （TOP1MT） 定位。染色质免疫沉淀测序、双荧光素酶报告基因测定和 RNA 免疫沉淀用于鉴定假基因、 miRNA 和真实基因之间的相互作用。体内实验验证了 TOP1MT 与假基因对顺铂耐药的相互作用。TOP1MT 被确定为体外、体内和 HNSCC 患者顺铂耐药的驱动因素。此外，TOP1MT 以信号肽依赖性方式异常易位到顺铂耐药 HNSCC 细胞的细胞核。核 TOP1MT （nTOP1MT） 转录调控线粒体功能假基因 MTATP6P1，该基因作为竞争性内源性 RNA （ceRNA） 与 miR-137 和 miR-491-5p 结合并促进 MTATP6 的表达。MTATP6 的增加增强了线粒体氧化磷酸化 （OXPHOS），从而在 HNSCC 中赋予顺铂耐药性。我们的研究结果显示，nTOP1MT 通过 ceRNA 转录激活 MTAPT6P1 并增加 MTATP6 表达，从而促进 OXPHOS 和顺铂耐药。这些结果为克服 HNSCC 中的顺铂耐药提供了新的见解。