miR-155靶向ANTXR2调控EMT介导肾癌舒尼替尼耐药的机制研究

Sunitinib is the first-line treatment for patients with metastatic renal cell carcinoma (mRCC). However, resistance to sunitinib becomes a major obstacle, resulting in failure of sunitinib treatment. Emerging studies have focused on the development of bio-marker to predict sunitinib treatment and have provided some insight into the underlying mechanisms of sunitinib resistance. It was reported that the level of miR-155 was significantly related to sunitinib resistance in a small cohort of mRCC patients. Recently, this finding has been validated in our cohort as well as in human renal cell carcinoma cell line (Caki-1) . But the function of miR-155 in sunitinib resistance is not fully elucidated. In our current research, we found Caki-1/SU, a resistance cell line generated by continuous exposure of sunitinib, displayed a higher level of N-cadherin but a lower level of E-cadherin, compared to sunitinib sensitive cell line Caki-1, which suggested that miR-155 contribute to epithelial-mesenchymal transition (EMT) , leading to sunitinib resistance. Through bioinformatic tools, we noticed that ANTXR2 was one of the target genes of miR-155. It has been reported that ANTXR2 can regulate EMT via Wint/β-catenin pathway in gastric cells. Therefore, we hypothesize that miR-155 regulates EMT via targeting ANTXR2 is an important mechanism of sunitinib-resistance in renal cell carcinoma. Here we aim to investigate the underlying roles and mechanisms of miR-155 in sunitinib-resistant renal cell carcinoma cell lines as well as in xenograft mice. With more understanding of its functions, miR-155 may be used as a predictive bio-marker and therapeutic target for mRCC treatment.

舒尼替尼耐药是造成晚期肾癌治疗失败的重要原因。我们的前期研究发现，晚期肾癌患者miR-155的表达与舒尼替尼敏感性负相关。与亲代敏感细胞相比，舒尼替尼耐药细胞高表达miR-155和N-cadherin，低表达E-cadherin，提示miR-155与上皮间质转化（EMT）密切相关。通过生物信息学手段我们发现ANTXR2可能是miR-155的靶基因，同时新近研究报道ANTXR2可调控胃癌细胞的EMT过程。因此我们推测：miR-155通过抑制ANTXR2的表达促进EMT发生可能是肾癌舒尼替尼耐药的重要机制。本研究拟从透明细胞肾癌细胞系和透明细胞肾癌裸鼠模型等方面，深入研究miR-155靶向ANTXR2介导EMT的机制，探索miR-155抑制剂反转舒尼替尼耐药的可行性，从而为晚期肾癌的联合用药提供理论依据。

舒尼替尼耐药是造成晚期透明细胞肾癌（cc-RCC）治疗失败的重要原因。上皮间质转化（EMT）是疾病进展和药物耐药的重要途经。我们前期研究发现，mir-155-5p在cc-RCC组织中异常表达，同时发现其与舒尼替尼敏感性呈负相关，说明mir-155-5p是舒尼替尼耐药的重要标志物。但其具体作用机制不详。生物信息学预测mir-155-5p可与ANTXR2这一重要分子结合，双荧光素酶报告基因实验示mir-155-5p可能与ANTXR2 3’UTR结合。因此，我们推测mir-155-5p在cc-RCC中通过调控下游靶基因ANTXR2的表达，参与EMT和舒尼替尼耐药。本项目从临床样本、细胞系、动物模型三个层面明确mir-155-5p对舒尼替尼耐药的影响，获得其通过靶向ANTXR2促进EMT的具体机制，最终解释mir-155-5p调控Wint/β-catenin 信号通路促进EMT诱导cc-RCC舒尼替尼耐药的分子机制，为临床cc-RCC患者个体化治疗提供新的理论依据。