PRRX1通过ERK途径促进胃癌顺铂耐药和转移的分子机制研究

Chemotherapy resistance and metastasis of gastric cancer during tumor treatment are one of the tricky problem. It is quite important to identify chemotherapy resistance and metastasis related biomarkers for individual treatment in gastric cancer. Previous studies found that overexpression of PRRX1 could promote gastric cancer cell resistance to cisplatin and enhance cell invasive ability through ERK signaling pathway. Our ChIP-seq results displayed that PRRX1 could regulate ABC transport and epithelial-related gene expression. Clinical pathological parameter analysis indicated that PRRX1 expression negatively correlated with gastric cancer patient prognosis, and positively correlated with lymph node metastasis and T stages. This project will utilize mouse tumorigenicity and lung metastasis models to investigate the function of PRRX1 in gastric cancer chemotherapy, metastasis and its ability of planting in the distant tissues. Combined with our ChIP-seq, gene differential expression profile and TCGA RNAseq results, select the chemotherapy and metastatic related genes, further elucidate the molecular mechanism of PRRX1 with these selected genes by utilizing ChIP-qPCR, EMSA, knocking down or overexpression, cell apoptosis, MTT and boyden chamber experiment et al. ERK might be the signaling pathway regulated by PRRX1 in its chemotherapy and metastasis. So we might use small molecule inhibitors towards ERK signaling pathway to study its function in chemotherapy and metastasis induced by PRRX1. Eventually, explore the treatment effect of cisplatin combined with ERK inhibitor in vivo and testify the clinical significance of PRRX1 and pivotal molecular. Our study intended to provide important clues for future researches on gastric cancer chemotherapy efficacy and early metastasis prediction, which will provide beneficial information for the gastric cancer patients in clinical practice.

耐药和转移是胃癌治疗的难题，寻找与其相关标志物对胃癌个体化治疗有着重要的临床意义。前期研究发现，体外细胞实验提示PRRX1过表达可以通过ERK信号途径促进胃癌细胞顺铂耐药和侵袭能力，ChIPseq结果提示PRRX1可以调节ABC转运和上皮相关基因；PRRX1表达与胃癌预后负相关和淋巴结转移等正相关。本课题拟通过体内小鼠荷瘤和肺转移模型，验证PRRX1在胃癌耐药和转移及其远处种植中的作用；通过对ChIPseq和现有数据分析，筛选和胃癌耐药和转移相关的候选基因，并通过ChIP-qPCR、EMSA、MTT药物筛选、侵袭转移及ERK抑制剂阻断等实验手段，分析验证候选基因以及ERK通路在PRRX1诱发胃癌顺铂耐药和转移中的具体作用机制和它们之间的相互关系；最后通过动物模型探索ERK抑制剂和顺铂联用的疗效，及PRRX1和获得关键靶蛋白在临床样本中验证，以期为胃癌顺铂耐药预测及早期转移提供分子靶标。

转移和耐药是胃癌治疗中的普遍难题，也是胃癌患者死亡的主要原因之一，故需要我们筛选出能够预测化疗疗效和早期干预转移的分子靶点。PRRX1可以促进胃癌淋巴结转移，是影响胃癌预后的不良因素，同时PRRX1和化疗耐药正相关，PRRX1表达阳性患者不能从化疗中获益。体内外实验证实胃癌细胞中PRRX1表达可以促进胃癌细胞的恶性表型特征：迁移和侵袭能力增加，其可以作为EMT-TF促进胃癌细胞上皮-间质转化；通过和XRCC5/6复合体结合促进DNA损伤修复能力，降低胃癌细胞对化疗药物的敏感性；敲低PRRX1表达，增加胃癌细胞对化疗药物的敏感性，同时PRRX1通过减少新抗原（neoantigen）产生，促进CD39表达，促进胃癌耐受微环境，为揭示胃癌转移、耐药和免疫的分子机制探索提供一种新思路。