MiR-495调控胶质瘤相关间充质干细胞分化及参与胶质瘤血管形成机制的研究

Glioma related mesenchymal stem cells (gb-MSCs) can differentiate into pericytes and participate in glioma angiogenesis in the microenvironment of glioma. Therefore, blocking the differentiation of gb-MSCs into pericytes and regulating the function of gb-MSCs have become the key to inhibit the angiogenesis of glioma. But gb-MSCs differentiation mechanism remains to be elucidated, the latest studies have shown that miR-495 can mediat the formation of new blood vessels, and our previous study confirmed that there was a significant difference in the expression of miR-495 before and after the differentiation of gb-MSCs, Based on the existing fundation, we hypothesized that the glioma microenvironment can induce the decrease of miR-495 expression in gb-MSCs, thereby promoting the expression of Bmi-1, and eventually mediating the differentiation of gb-MSCs into vascular pericytes and participating in the formation of glioma blood vessels. In addition, in vitro and in vivo experiments were conducted to investigate the effect of miR-495 on the differentiation of gb-MSCs into pericytes and its involvement in the angiogenesis of glioma by using a variety of genes, cell technologies and biological functional methods, and to elucidate its mechanism, so as to provide a new target basis for the anti-angiotherapy of glioma.

胶质瘤相关间充质干细胞（gb-MSCs）在胶质瘤微环境中能向血管周细胞分化并参与胶质瘤新生血管形成，因此，阻断gb-MSCs向血管周细胞分化及调控gb-MSCs的功能成为抑制胶质瘤新生血管形成的关键，但gb-MSCs分化的机制仍有待阐明，最新研究显示miR-495能介导新生血管的形成，且本课题组前期研究证实gb-MSCs分化前后miR-495表达存在明显差异，基于此提出假设：胶质瘤微环境能诱导gb-MSCs中miR-495表达降低，从而促进Bmi-1的表达，最终介导gb-MSCs向血管周细胞分化并参与胶质瘤血管的形成。并在体外和在体实验中进行研究，采用多种基因、细胞技术及生物功能学方法探讨miR-495对gb-MSCs向血管周细胞分化及其参与胶质瘤血管形成的影响，并阐明其机制，为胶质瘤的抗血管治疗提供新的靶点依据。

胶质瘤是人体常见的恶性肿瘤之一，越来越多的研究胶质瘤微环境在肿瘤的发生及生长过程中起着至关重要的作用，其中胶质瘤相关间充质干细胞与胶质瘤的生长、侵袭、血管生成及耐药性方面关系密切。本课题主要通过对提取胶质瘤相关间充质干细胞、肿瘤干细胞等进行基因芯片、ELISSA、WESTERN-BLOT、免疫荧光、免疫组化等试验，研究胶质瘤相关间充质干细胞对胶质瘤耐药性、血管生成的影响，从而为胶质瘤的治疗提供新的方向及策略。目前本课题组的相关实验结果显示：1.胶质瘤相关间充质干细胞培养液能促进胶质瘤细胞的增殖、迁移、及耐药性，同时胶质瘤相关间充质干细胞培养液能促进胶质瘤表达FOXS1、激活上皮间质细胞转化，从而增强胶质瘤细胞对替莫唑胺的耐药性，其中CD90低表达的胶质瘤相关间充质干细胞能分泌大量IL-6，被证实能促进胶质瘤细胞FOXS1的表达，为胶质瘤治疗提供了相关耐药性方面的新靶点。2.胶质瘤中EDEM2的表达显著增加且患者预后更差，而EDEM2的表达差异与IDH的状态，1p/19q的共缺失，肿瘤分级、主要治疗结果以及病理类型有关，EDEM2高表达样本的巨噬细胞、总T淋巴细胞和中性粒细胞浸润水平明显较高，同时，EDEM2能增强胶质瘤细胞的迁移和侵袭能力，此外，美帕曲星、考比替尼、司美替尼、曲美替尼、达拉非尼可作为相应的靶向治疗药物。该结论提示EDEM2可能是一种有用的生物标志物，用于诊断、治疗以及评估胶质瘤的预后，为更深入地了解EDEM2的分子病因提供了新的视角。3.本课题组研究还发现，胶质瘤干细胞通过SDF-1相关通路促进间充质干细胞的迁移及招募，胶质瘤干细胞外泌体通过mi-RNA320a促进胶质瘤相关间充质干细胞向血管周细胞分化，明显增强其周细胞标记物NG2、PDGFRβ、α-SMA的表达，该结论同样为胶质瘤抗血管治疗提供了新的治疗靶点。