NONO招募RPLP0增强DNA损伤修复促进肿瘤放疗抵抗的机制研究

放疗抵抗是肿瘤放疗失败的重要原因，其机制尚不明确。基于全基因组Crispr/Cas9敲除文库（Hepatology，2019第一作者），我们鉴定出NONO是放疗抵抗的关键调控分子；蛋白质谱检测提示RPLP0是NONO的结合蛋白，放射线照射后二者在胞核内的结合显著增加，后移位于DNA损伤位点，增强DNA损伤修复能力。临床层面，较之正常组织细胞，NONO与RPLP0在肿瘤细胞中的结合量较高；NONO的高表达与放疗抵抗正相关。已知细胞DNA损伤修复能力强可导致放疗抵抗。由此，我们提出肿瘤放疗抵抗的新机制：NONO招募RPLP0至DNA双链的损伤位点，促进损伤末端的修复，诱导放疗抵抗。基于此，本项目拟采用基因敲除、高通量测序等方法，结合PDX模型及临床验证，最终阐明放射线照射时NONO招募RPLP0，二者识别并结合损伤的DNA双链断端，促进末端修复的具体分子机理，为基于此的靶向放疗增敏提供理论依据

Radio-resistance leads to the failure of cancer treatment and its underlying mechanisms are largely unknown. In the previous study, we used genome-wild CRISPR/cas9 knockout library (Hepatology, 2019, First author) to screen the key regulators of radio-resistance, and found that NONO enhanced radio-resistance and DNA damage repair. The results of CoIP and LC/MS assay showed that radiation significantly enhanced the association between NONO and ribosomal protein RPLP0 in nucleus. NONO and RPLP0 bound to DNA damage loci and promoted the repair of double strand break DNA. Analysis of clinical samples showed that the association between NONO and RPLP0 was enhanced in tumor cells and the level of NONO was correlated with radio-therapy response of colorectal cancer patients. As reported, DNA damage repair enhances tumor radio-resistance. Therefore, we hypothesized that radiation-induced recruitment of RPLP0 by NONO to DNA damage loci promotes the repair of DNA breaks, and enhances tumor radio-resistance. Based on these preliminary findings, we will conduct molecular biology experiments including gene knockout and high-throughput deep sequencing, and use PDX model and clinical samples, to elucidate a novel mechanism that radiation induced the recruitment of RPLP0 to damaged DNA sites by NONO, therefore enhanced DNA repair and tumor radio-resistance. Our findings will provide novel molecular targets for cancer treatment.