hsa_circ_406888促进VEGF相关外泌体分泌并动员循环内皮祖细胞参与肾癌血管生成的机制研究

Previous studies showed that the circulating endothelial progenitor cells (CEPCs) were involved in angiogenesis of renal cell carcinoma (RCC), however, the mechanism remains unclear. Our previous studies demonstrated that high level of CEPCs was detected in RCC patients and positively correlated with the level of VEGF in blood serum. We next used immunohistochemistry, Protein-Chip Technology and bone marrow transplantation (BMT) mice model to observe that exosome-transmitted VEGF was the main factor in the process of promoting CEPCs participated in angiogenesis of RCC. Furthermore, we explored the potential binding sites between hsa_circ_406888 and miR-646 as well as the putative 3’UTR of VEGF towards miR-646 through high throughput microarray and bioinformatics analysis. Therefore, we raise the hypothesis that high expression of hsa_circ_406888, serving as ceRNA, directly binds and suppresses miR-646 expression, and then stimulates the synthesis and secretion of VEGF-associated exosome, which enhances CEPCs involved in angiogenesis of RCC. We will further clarify the clinical relationship among hsa_circ_406888, miR-646 and VEGF expression, and illustrate the mechanism of the synthesis and secretion of VEGF-associated exosome from hsa_circ_406888. This study will reveal a novel mechanism of RCC progression, and also provide a new therapeutic approach of RCC.

研究表明循环内皮祖细胞（CEPCs）参与肾癌血管生成，但具体机制尚不明确。我们前期发现CEPCs在肾癌患者体内高表达且和血清VEGF正相关，随后利用免疫组化、蛋白芯片和BMT模型小鼠检测发现外泌体转运的VEGF是动员CEPCs参与肾癌血管生成的主要因子。进一步通过高通量芯片筛选和生信分析发现hsa_circ_406888和miR-646有结合序列且miR-646结合VEGF的3’UTR。因此，我们推测肾癌细胞中高表达的hsa_circ_406888作为ceRNA结合并抑制miR-646，促进VEGF相关外泌体分泌进而动员CEPCs参与肾癌血管生成。我们将进一步明确hsa_circ_406888、VEGF和CEPCs临床表达相关性，阐明hsa_circ_406888促进VEGF相关外泌体分泌机制。本项目将从circRNA，外泌体和CEPCs角度揭示肾癌进展新机制，为肾癌临床诊治提供新的靶点。

肾透明细胞癌（ccRCC）的治疗存在明显的个体差异，是容易产生耐药的肿瘤之一，且多为天然耐药，临床化疗有效率仅为7-10%。随着靶向药时代到来，舒尼替尼成为新的一线治疗方案。然而，一般来说晚期ccRCC患者使用舒尼替尼治疗，无进展生存期都为1年，近半数在1年内已经发生耐药。本课题通过研究发现舒尼替尼耐药ccRCC组织中肥大细胞浸润增加；共培养条件下肥大细胞外泌体递送miR-452-5p至ccRCC细胞诱导舒尼替尼耐药，SOCS5/JAK/STAT3是潜在信号通路。此外共培养后ccRCC细胞IL33分泌增加，并预测经ST2/NF-κB/ELAVL1通路促进肥大细胞外泌体介导的miR-452-5p分泌。因此我们提出，miR-452-5p相关外泌体和IL33介导肥大细胞和ccRCC细胞间对话，形成正反馈环路诱导舒尼替尼耐药。本研究为肥大细胞外泌体miR-452-5p诱导舒尼替尼耐药奠定了较为扎实的理论基础，同时对ccRCC细胞分泌的IL33对肥大细胞外泌体miR-452-5p分泌的调控机制提供了重要的启示性线索。项目资助发表SCI论文7篇，培养博士生1名，其中1名已经顺利毕业并获得学位。项目投入经费55万元，支出44.6782万元，各项支出与预算相符。剩余经费10.3218万元，剩余经费计划用于本项目研究后续支出。