PLAG1与miR-296/298簇反馈通路激活VEGFA/VEGFR2信号促进胃癌血管新生的研究

Sustained activation of VEGFA/VEGFR2 signaling constitutes an important molecular pathological basis of angiogenesis in gastric cancer. Our previous research found that angiogenesis related miR-296/298 cluster miRNA:miR-296-5p was upregulated in gastric cancer, and transcription factor PLAG1 could promote miR-296/298 cluster expression, and various sumoylation related genes inhibiting the transcriptional activity of PLAG1 were direct targets of miR-296/298 cluster miRNAs. Overexpression of miR-296/298 cluster could enhance the transcriptional activity of PLAG1 possibly via inhibiting its sumoylation. Meanwhile, we verified the previous conclusion that VEGFA is upregulated by PLAG1 and HGS degradating VEGFR2 is targeted by miR-296-5p. Alterations of VEGFA/VEGFR2 expression and in vitro angiogenesis were observed after the intervention of PLAG1 or miR-296/298 cluster. So we put forward the hypothesis that there was a feedback loop between PLAG1 and miR-296/298 cluster, which sustained VEGFA/VEGFR2 signaling, promoting angiogenesis in gastric cancer. We will elucidate our hypothesis based on clinical samples detection, molecular mechanism exploration and efficacy validation in vitro and in vivo. This study will enrich the molecular mechanism of gastric cancer angiogenesis, and provide valuable basic research information for antiangiogenic therapy in gastric cancer.

VEGFA/VEGFR2信号活化构成胃癌血管新生的重要分子病理基础。我们发现血管新生相关miR-296/298簇miRNA：miR-296-5p在胃癌中上调，转录因子PLAG1可促进miR-296/298簇表达，且miR-296/298簇可靶向抑制多种蛋白苏素化修饰基因，上调miR-296/298簇可能抑制PLAG1苏素化修饰而增强其转录活性。课题组亦验证了既往结论：VEGFA受PLAG1转录，miR-296-5p靶向抑制VEGFR2降解蛋白HGS从而维持VEGFR2表达，干预PLAG1或miR-296/298簇，可影响VEGFA/VEGFR2表达及体外血管新生。由此，我们提出假说：PLAG1与miR-296/298簇之间存在反馈通路，导致VEGFA/VEGFR2信号活化促进胃癌血管新生。我们拟结合临床样本检测，细胞、分子机制研究及体内外效能验证，阐明该假说，以利胃癌抗血管新生治疗。

鉴于高通量测序技术的全面发展，肿瘤及正常人多组学（涉及基因组、转录组、蛋白组、表观组等）大数据库正逐渐释放、公布，比如：TCGA、ICGC、GTEx等，随着肿瘤大样本数据与临床表型关联性分析的推进，更贴近临床实际的分子靶点日趋被发现，在此大数据背景下，课题组进行了泛癌种循环（血浆、血清）miRNAs特征表达谱的研究。同时，将泛癌种循环miRNAs特征表达谱与胚胎循环miRNAs特征表达谱进行整合比对与分析，不仅有利于国人肿瘤的筛查与防控，更利于高权重抗肿瘤miRNAs靶点的发现；同时，进行了肿瘤循环代谢组学的工作，通过从肿瘤循环miRNAs组学与肿瘤循环代谢组学两个侧面的探索，提高对肿瘤的发生、发展，包括血管新生、免疫逃逸等的认识。本项目建立了泛癌种循环miRNAs及癌胚循环miRNAs表达谱，同时发现了潜在优于原课题中的miRNA血管新生调控靶标及其他抗肿瘤miRNAs调控靶标。发表相关论文31篇，其中SCI论文25篇，获得国家发明专利授权12项，申请国际发明专利1项。完成了项目既定的研究目标及内容，并为后续肿瘤相关研究，打好了坚实的基础。