TGF-β促发脂肪间充质干细胞可控分泌BMP4抑制胶质母细胞瘤的实验研究

Glioblastoma (GBM) has a poor prognosis despite current best treatment practices. However, Stem cells, which are a result of their intrinsic ability to deliver therapeutic genes or proteins, have been regarded for their clinical therapeutic potential for GBM. Our previous studies showed that primary human Adipose-derived mesenchymal stem cells (hAMSCs) which were engineered by BMP4 can migrate to sites of GBM and suppress their proliferation and renewal capacity. However, it remains unclear whether the BMP4 has negative effects on the normal brain tissue. The goal of this project is to establish a viral vector (SBE4BMP4-hAMSCs) which can be used as a selective delivery vehicle of BMP4 under a “switch” of TGF-β. Thus, the hAMSCs will express BMP4 when trigged by TGF-β which is highly expressed by GBM. Meanwhile, they will not secret or rarely secret BMP4 when they locate normal area. Moreover, the nanoparttern model, luciferase assay and molecular experiment will be performed to determine whether BMP4-secreting hAMSCs under the control of TGF-β have an anti-GBM response in vitro and in vivo. This study may provide insight into improving the curative effect of hAMSCs for the treatment of GBM.

胶质母细胞瘤（GBM）的治疗至今尚无突破性进展，利用干细胞作为运载载体的生物治疗模式被视为改善GBM预后的新希望。我们前期工作证实，人脂肪间充质干细胞（hAMSCs）可趋化迁移至GBM周围并分泌已转染至其中的BMP4，从而抑制肿瘤生长，促进其分化。然而上述研究中，hAMSCs分泌BMP4的过程不具有针对性，且其可能对正常脑组织存在不利影响。本项目拟在前期基础上改进方法，利用GBM与正常脑组织表达TGF-β存在显著性差异这一特点，构建新的载体系统SBE4BMP4-hAMSCs，从而使hAMSCs在“识别”肿瘤区域高水平TGF-β后才启动BMP4的表达，在正常区域不表达或低表达BMP4，进而实现对靶向药物的可控分泌；同时通过纳米模型、荧光标记、分子生物学等技术验证上述载体系统在体内、外抑制GBM的效果及相关机制，为hAMSCs可控分泌BMP4抑制GBM的进一步应用提供理论依据和实验基础。

我们前期工作证实，间充质干细胞（MSCs）可趋化迁移至GBM周围并分泌已转染至其中靶向药物，从而抑制肿瘤生长，促进其凋亡。然而上述过程中，干细胞分泌靶向药物不具有针对性，且其可能对正常脑组织存在不利影响。本项目组利用GBM 与正常脑组织表达TGF-β有显著性差异这一规律， 并在前期的工作基础上， 研究设计hAMSCs-SBE4-BMP4运载系统以及hAMSCs-SBE4-TRAIL 运载系统，实现TGF-β调节靶向蛋白分泌，从而将靶向抑制GBM 的过程变得更加精准可控，同时将“误伤”几率降到更低，为干细胞可控分泌靶向药物抑制GBM的进一步应用提供理论依据和实验基础。在实施项目的过程中，本项目组已验证模型小鼠在经过hAMSCs-SBE4-TRAIL 运载系统的治疗过程中，其肿瘤细胞被明显抑制，动物模型生存时间明显延长，课题组按计划完成本课题的构思和假设，进而从体外到体内，从治疗效果到安全性能，全方位的验证MSC作为细胞资源，靶向治疗胶质母细胞瘤的实验研究,为未来进一步的应用提供理论和实验基础。本项目内容已按计划全部完成，并将结果整理成了3篇SCI论文，其中两篇已见刊，1篇在投。