Senataxin regulates cisplatin resistance through an R-loop mediated mechanism in HPV-associated Head and Neck Cancer

Resistance to cisplatin is a key clinical concern in HPV-independent (HPV-) and HPV-associated (HPV+) head and neck cancer. Upregulation of DNA repair is known to contribute to cisplatin resistance and a major source of endogenous DNA damage are DNA/RNA hybrids, known as R-loops. Following creation of HPV+ and HPV- cisplatin resistant cell lines, RNA-Sequencing revealed alterations in the expression of known R-loop regulators. Resistant cells had elevated global R-loop levels and in HPV+ resistant cells there was a corresponding upregulation of the R-loop resolving protein, senataxin. Depletion of senataxin led to increased sensitivity to cisplatin, an increase in DNA damage and elevated R-loops at specific genomic loci. In summary, using an in vitro model of cisplatin resistance, we identified that senataxin modulates sensitivity to cisplatin through an R-loop mediated mechanism in HPV+ cells. R-loops may represent a potential therapeutic target and warrant further investigation. Overall design: To investigate cisplatin resistance in HPV+ and HPV- cells, cisplatin resistance clones were developed and RNA-Sequencing was carried out on the parental clones and their resistant counterparts.

顺铂（cisplatin）耐药是人乳头瘤病毒（HPV，Human Papillomavirus）独立型（HPV-）及人乳头瘤病毒相关型（HPV+）头颈部癌症的核心临床难题。
现有研究证实，DNA修复通路的上调是顺铂耐药的重要致病机制，而内源性DNA损伤的主要来源为被称为R环（R-loops）的DNA/RNA杂交复合体。
在成功构建HPV+及HPV-顺铂耐药细胞株后，RNA测序（RNA-Sequencing）结果显示，已知的R环调控因子的表达水平发生了显著改变。
耐药细胞的整体R环水平显著升高，且在HPV+耐药细胞中，负责R环解旋的蛋白森塔克辛（senataxin）也出现了相应的表达上调。
敲低森塔克辛会使细胞对顺铂的敏感性增强，同时加剧DNA损伤，并在特定基因组位点上提升R环的水平。
综上，本研究通过顺铂耐药的体外模型证实，在HPV+细胞中，森塔克辛可通过R环介导的通路调控细胞对顺铂的敏感性。
R环有望成为潜在的治疗靶点，值得开展进一步的深入研究。
实验整体设计：为探究HPV+与HPV-细胞的顺铂耐药机制，本研究构建了顺铂耐药细胞株，并对亲本细胞株及其耐药衍生株开展了RNA测序（RNA-Sequencing）分析。