CRIP1核聚积通过调控DNA同源重组修复影响胃癌细胞化疗敏感性的机制研究

同源重组（HR）修复与化疗敏感性密切相关，其调控机制尚不明确。CRIP1是我们分析TCGA胃癌数据库发现的，与组织HR修复缺陷评分呈负相关的LIM家族小分子蛋白，其功能迄今鲜有报道。前期预实验表明：化疗触发CRIP1核聚积；沉默CRIP1抑制胃癌细胞HR修复并增强顺铂、表柔比星的敏感性。分子机制上，沉默CRIP1分别于转录和转录后水平影响RAD51及TP53的表达。蛋白质谱显示，顺铂可触发CRIP1与RPL5结合，后者可于胞核基质结合并抑制MDM2活性维持TP53稳定，提示CRIP1核聚积有利其对HR的调控。综上，我们推测：CRIP1核聚积是胃癌细胞响应并抵御化疗带来的DNA损伤的机制之一，核定位的CRIP1通过与MDM2竞争结合RPL5，破坏TP53稳定性，上调RAD51转录表达，最终促进HR修复引起耐药。本项目将通过临床样本分析及体内外实验验证上述假设，以期为胃癌化疗增敏提供新分子靶点

Homologous recombination (HR) repair is closely related to chemotherapy sensitivity, and its modulatory mechanism is unknown. CRIP1 is a small molecular protein of the LIM family, which was found in our analysis of the TCGA gastric cancer database and has a negative correlation with the tissue HR repair defect score. Its function has yet to be reported. Preliminary experiments indicated that: chemotherapy triggers CRIP1 nuclear accumulation; silencing CRIP1 inhibits HR repair of gastric cancer cells and enhances the sensitivity to cisplatin and epirubicin. Molecularly, silencing CRIP1 affects the expression of RAD51 and TP53 at the transcriptional and post-transcriptional levels, respectively. The protein profile demonstrated that cisplatin can trigger the binding of CRIP1 to RPL5, which can bind to the nuclear matrix and inhibit the activity of MDM2 to maintain the stability of TP53, suggesting that nuclear accumulation of CRIP1 is conducive to its regulation of HR. Collectively, we speculate that: CRIP1 nuclear accumulation is one of the mechanisms by which gastric cancer cells respond to and resist DNA damage caused by chemotherapy. Nuclear-localized CRIP1 competes with MDM2 to bind RPL5, disrupts TP53 stability, up-regulates RAD51 transcription expression, and ultimately promotes HR Repair to achieve sensitization. This project will verify the above hypotheses through clinical sample analysis and in vivo and in vitro experiments, with a view to providing novel molecular targets for gastric cancer chemotherapy sensitization.