RARRES3经MTDH相互作用调控结直肠癌EMT及转移发生的机制研究

Metastasis is the major cause of cancer related death in colorectal cancer (CRC) patients. Epithelial-mesenchymal transition (EMT) has been considered to play a vital role in CRC metastasis. Our previous studies showed that Retinoic acid receptor responder 3 (RARRES3) was able to inhibit EMT process in CRC. Interestingly, the translocation of beta-catenin from cytoplasm to nucleus was also discovered when we knocked down RARRES3 in CRC cells. Moreover, we performed immunoprecipitation and confirmed that RARRES3 could physically interact with Metadherin (MTDH). Based on these results we proposed that RARRES3 interacts with MTDH to alter the dynamic distribution of beta-catenin in CRC cells, and thus regulats EMT and CRC metastasis. In this project, we will use an inducible system and orthotopic transplantation mouse model to study the biological function of MTDH in vitro and in vivo; we will further investigate the molecular mechanism of RARRES3 and MTDH in changing the distribiution of beta-catenin in the process of cell EMT. All these findings will be further validated in human patient samples. In summary, this work is to investigate the molecular mechanism of the interaction between RARRES and MTDH in CRC progression, test their functions in vitro and in vivo, and also demonstrate their role in CRC patient specimens.Therefore, we will demonstrate the role of RARRES3 and MTDH from all aspect and provide novel thinking and strategy for the biological therapy of CRC.

肿瘤转移是结直肠癌患者死亡的主要原因，其发生的重要机制之一是上皮间质转化（EMT）。我们前期研究发现：视黄酸受体反应元件3（RARRES3）可抑制结直肠癌细胞EMT；在肿瘤细胞敲除或过表达RARRES3，导致β-catenin在细胞核与质之间分布改变；免疫共沉淀发现RARRES3与肿瘤相关蛋白Metadherin（MTDH）有相互作用。据此，我们提出假设：RARRES3经MTDH相互作用改变β-catenin在细胞内的动态分布，进而调控EMT发生与结直肠癌转移。本项目拟利用可诱导系统和体内原位移植模型，探索RARRES3与MTDH相互作用对肿瘤转移的生物学作用；分子水平明确两者相互作用对β-catenin在细胞中分布的影响及EMT调控机制；在结直肠癌组织中加以验证。从分子、细胞、小鼠模型及人类肿瘤组织等水平阐述RARRES3与MTDH互相作用对结直肠癌转移的作用，为其生物学治疗提供新策略。

前期工作基础免疫共沉淀发现RARRES3与肿瘤相关蛋白Metadherin（MTDH）有相互作用。通过完成相关体外试验，初步探讨了MTDH靶蛋白DDR1\PGAM1促进结直肠肿瘤进展的的可能机制。.通过体内实验证实DDR1可促使肿瘤细胞增殖侵袭；敲除或过表达DDR1、PGAM1，可导致肿瘤细胞内Wnt/β-catenin信号通路相关靶蛋白表达发生变化。进一步研究证实DDR1\PGAM1，促使Wnt/β-catenin信号通路激活，进而促进结直肠癌进展。不仅补充了MTDH作为抑癌基因治疗结直肠癌的理论基础。从而丰富完善了RARRES3经MTDH相互作用调控结直肠癌转移进展的机制。