HOXA10调控TGFβ2-Smad通路促进结肠癌发生转移的作用机制研究

It is known that tumorigenesis is an aberrant form of organogenesis. The colon tissue-specific of HOXA10 was addressed in embryonic development via whole mount by the research team for the first time. The expression of HOXA10 in human normal colon mucosa - adenoma - adenocarcinoma-metastasis was up-regulated. Moreover, up-regulated HOXA10 was significantly associated with lymph node and distant metastasis. Overexpression of HOXA10 could improve cancer cell cloning, migration and invasion abilities, while the cells morphology showed EMT under the microscope. TGFβ2, EMT inducing factor, can further enhance their migration and invasion abilities; however, TGFβ2 neutralized antibody can reverse their abilities. But overexpression of HOXA10 in the SW480 cells which were in the absence of Smad4, key medium of Smad classic pathway, could not enhance migration and invasion abilities. Therefore, TGFβ2 was the target gene of HOXA10 regulation. HOXA10 could activate EMT program by regulating TGFβ2-Smad pathway, leading to increase tumor invasion and migration abilities, promoting the occurrence and metastasis of colon cancer. Therefore, the next applicants intend to further the archiving of clinical samples and information to identify HOXA10 as a sensitive marker for tumor metastasis. Through positive and negative intervention in Smad3 expression, we aim to confirm the role of HOXA10 in promoting metastasis of colon cancer mainly by TGFβ2-Smad pathway. Combining with PCR-array, we aim to make clear the mechanism how HOXA10 regulates the TGFβ2-Smad pathway as well as provide a new target for drug therapy.

课题组前期首次发现HOXA10在小鼠全胚胎发育中有结肠组织特异性；在人正常粘膜-腺瘤-腺癌-转移过程中表达呈渐进性，并与淋巴结、远处转移显著相关。HOXA10过表达的结肠癌细胞呈EMT化，侵袭能力显著增强；给予EMT诱导因子TGFβ2可进一步增强其侵袭性，而TGFβ2中和抗体能逆转其侵袭能力。Smad是 TGFβ2下游通路的关键介质，在Smad缺乏的结肠癌细胞中过表达HOXA10，细胞侵袭能力无明显增强。据此分析，HOXA10通过TGFβ2-Smad途径激活EMT促进结肠癌的发生和转移。本研究拟进一步增加结肠癌样本以检测HOXA10在转移中的表达；克隆TGFβ2启动子区以鉴定HOXA10与TGFβ2结合序列；正负向调控Smad3验证HOXA10主要通过Smad依赖途径调控转移；应用PCR-array等明确HOXA10调控TGFβ2-Smad通路的机制。旨在为结肠癌治疗及监测转移提供新靶点。

课题组首次发现HOXA10在小鼠全胚胎发育中有结肠组织特异性；在人正常粘膜-腺瘤-腺癌-转移过程中表达呈渐进性，并与淋巴结、远处转移显著相关。HOXA10过表达的结肠癌细胞呈EMT化，侵袭能力显著增强；给予EMT诱导因子TGFβ2可进一步增强其侵袭性。HOXA10通过TGFβ2-Smad途径激活EMT促进结肠癌的发生和转移。同时，课题组收集和扩大结直肠癌样本后，分析和验证我院结直肠癌患者化疗方案与NCCN指南一致，并且进一步发现病理分子能指导结直肠癌个体化化疗。此外，我们发现HOXA13是胃癌的新的肿瘤标志物，并且HOXA13通过DHRS2发挥促进胃癌发展的作用；我们发现TRIM3在结直肠癌中异常表达，TRIM3通过P53依赖途径促进结直肠癌的进展。