经血干细胞携带基因工程化的溶瘤腺病毒靶向治疗大肠癌的效能及机制研究

Colorectal cancer (CRC) is one of the most common gastrointestinal cancer. In recent years, the incidence and mortality of CRC are increasing in China. Tremendous advances in the development of virotherapeutics have been seen for CRC. Despite this promise, clinical advancement of this powerful approach has been hindered by vulnerability to host defenses and inefficient systemic delivery. In this study, we will firstly determine the CRC tropic ability of menstrual blood-derived stem cells (MenSCs) by a noninvasive in vivo assay using IVIS imaging system. Then, we decide to use MenSCs as a cellular vehicle for targeted delivery the Ad5/F11 chimeric oncolytic adenovirus with Ad11 fiber. After optimization of the Ad5/F11 infection protocol, the TRAIL-IETD-Endo gene was inserted into the Ad5/F11 vector. Co-culture and Transwell experiments will be used to assess the anti-tumor efficacy of MenSCs-Ad5/F11-TRAIL-IETD-Endo in vitro. Furthermore, the in vivo therapeutic efficacies and mechanism of the MenSCs-Ad5/F11-TRAIL-IETD-Endo will be investigated on an established CRC patient-derived tumor tissue (PDTT) xenograft models. The present study will also determine the efficacy of MenSCs-Ad5/F11-TRAIL-IETD-Endo combined with chemotherapy or target therapy in order to identify whether the MenSCs-based gene-virotherapy have synergistic effect for CRC treatment. This study will provide MenSCs as a vehicle for stem cell-based CRC-targeted gene-virotherapy, and find an optimal transplantation strategy for injection of this therapeutic method.

大肠癌的基因病毒治疗因其在动物实验中的良好表现而受到高度关注，但对肿瘤部位缺乏靶向性使其难以达到理想的临床治疗效果。预实验结果显示MenSCs具有体内趋向损伤部位和体外趋向大肠癌细胞及其上清的特性，预示MenSCs可以作为细胞载体更有效地将病毒送至大肠癌部位。本项目拟通过活体成像技术和体外迁移模型明确MenSCs对大肠癌的趋向性，阐明大肠癌分泌细胞因子在引起MenSCs靶向迁移中的作用；构建表达TRAIL-IETD-Endo基因的嵌合型Ad5/F11溶瘤腺病毒，明确其体外、体内对大肠癌的作用及治疗机制；结合大肠癌PDTT移植瘤模型比较化疗和肿瘤部位靶向基因病毒治疗联用在不同个体间治疗效果的差异。本项目所研制的MenSCs-Ad5/F11-TRAIL-IETD-Endo弥补了传统病毒肿瘤部位靶向性差的缺陷，具有更强的治疗效果，为大肠癌的临床治疗提供新途径。

本研究内容按照计划完成了对经血来源间充质干细胞（MenSCs）的生物学特性分析，并在此基础上明确其对肝损伤治疗的缓解作用；优化了基因-病毒治疗策略，构建了重组溶瘤腺病毒Ad5/F11-TRAIL-IETD-Smac，发现TRAIL和Smac具有协同抗大肠癌的功能。我们利用Transwell迁移模型和皮下接种大肠癌细胞的移植瘤动物模型证明了MenSCs在体内外对大肠癌具有趋向性，明确了其作为肿瘤基因治疗载体的可行性。同时，成功构建携带重组溶瘤腺病毒Ad5/F11- TRAIL- IETD-Smac的经血来源间充质干细胞（MenSC-Ad5/F11-TRAIL-IETD- Smac），体内外评估其对肿瘤的趋向性及杀伤作用，明确了MenSC-Ad5/F11- TRAIL-IETD-Smac靶向治疗大肠癌的效果，并对其靶向治疗作用机制进行了初步探讨。研究内容基本按照计划完成，其中由于实验条件限制，本项目构建的大肠癌PDTT移植瘤模型数量足以完成原计划动物实验，变更为大肠癌细胞构建的皮下大肠癌动物模型用于实验，研究结果依然真实可靠。