RAGE通路促进结直肠癌干细胞扩增的作用和机制研究

Recent investigations indicated that Receptor of Advanced Glycation Endproducts (RAGE) played a crucial role in the tumorigenesis of multiple cancer types. However, the underlying molecular mechanism remains largely elusive. In the present project, we identified that RAGE was highly expressed in colorectal cancer stem cells, and that RAGE interacted with K-Ras and activated its downstream pathways. Based on these findings, we propose that RAGE may promote the expansion of colorectal cancer stem cells through the activation of Ras signaling. We aim to first analyze the correlation among the expression of RAGE and stem cell markers, as well as the pathological parameters of colorectal cancer patients. Next, we investigated the role of RAGE in the regulation of K-Ras signaling using colorectal cancer cell lines. In addition, the contribution of RAGE-mediated Ras activation on the expansion of colorectal cancer stem cell population and the expression of stem cell marker proteins will also be explored. Finally, we will employ nude mice to determine the influence of RAGE/Ras signaling on in vivo colorectal cancer progression. Our study may help clarify the molecular mechanism underlying the facilitating role of RAGE in colorectal cancer, and benefit the investigations on the therapy of colorectal cancer in this regard.

近年来研究发现晚期糖基化终末产物受体（RAGE）在肿瘤的进程中发挥重要的推动作用，但确切的机制未明。课题组前期预实验发现RAGE在结直肠癌干细胞中明显高表达，且RAGE可直接结合并活化K-Ras及其下游信号通路。基于此，我们提出RAGE可通过活化Ras通路促进结直肠癌干细胞扩增的设想。我们拟首先分析结直肠癌组织中RAGE的表达和干细胞标志物、病人病理参数及预后的相关性；进而利用结直肠癌细胞系明确干预RAGE和Ras对结直肠癌干细胞群及干细胞标志物表达的影响；最后，我们拟构建裸鼠荷瘤模型分析RAGE通过Ras促进结直肠癌进程的机制。我们的研究有助于阐明RAGE通路对结直肠癌发生发展的分子机制，并为基于此通路的肿瘤治疗提供新的理论依据。

近年来研究发现晚期糖基化终末产物受体（RAGE）在肿瘤的进程中发挥重要的推动作用，但确切的机制未明。课题组前期预实验提示RAGE在结直肠癌干细胞中明显高表达，且RAGE可直接结合并活化K-Ras及其下游信号通路。基于此，我们提出RAGE可通过活化Ras通路促进结直肠癌干细胞扩增的设想。本项目主要从分子、细胞、动物水平探讨了RAGE通路的活化对结直肠癌干细胞群体的调节作用、RAGE与Ras的相互作用及调节机制、RAGE对Ras下游通路的调节以及这一机制对肿瘤干细胞的影响。经研究发现：HMGB1显著促进结直肠癌细胞的增殖，Ras抑制剂FTS可减弱HMGB1介导的结直肠癌细胞增殖，RAGE或Yap1的表达缺失也减弱HMGB1介导的结直肠癌细胞增殖；结直肠癌细胞和组织中RAGE蛋白与K-RAS蛋白均为高表达且相互关联、相互作用；在结直肠癌细胞中，HMGB1促进CD44、Sox2、Yap1的表达，当在此基础上加入抑制剂后，表达水平显著降低；所选结直肠癌细胞内均有CD44阳性细胞，HMGB1处理后，CD44阳性细胞比例显著增加，当在此基础上加入Ras抑制剂后，CD44阳性细胞比例减少；HMGB1处理后，结直肠癌细胞的成球能力增强，FTS处理或RAGE、Yap1干扰导致HMGB1处理后的结直肠癌细胞球形成能力降低；结直肠癌标本中的RAGE蛋白和YAP1蛋白均为高表达，与晚期组织学分级、淋巴结转移和TNM分期有关；裸鼠体内成瘤实验与细胞实验的结果类似。. 研究结果发现HMGB1-RAGE信号促进K-RAS介导的YAP1表达，进而促进结直肠癌的干细胞性和进展，为炎症引起的结直肠癌发展机制提供了新的思路。研究成果可以为结直肠癌的新型靶向治疗药物的开发提供一定的科学依据。