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中南大学梁德生课题组发表基因编辑干细胞对肿瘤生长抑制的研究进展
2017年3月27日，，国际肿瘤学学术期刊《Oncotarget》杂志上在线发表了中南大学生命科学学院医学遗传学国家重点实验室梁德生课题组在基因编辑干细胞抑制肿瘤生长研究的新进展，文章题为“Enhanced tumor growth inhibition by mesenchymal stem cells derived from ipsCs with targeted integration of interleukin 24 into rDNA loci”，博士研究生刘博为第一作者，梁德生教授和刘雄昊副教授为共同通讯作者。
间充质干细胞(MSCs)存在于骨髓、血液、脂肪等多种组织中，是一种具有多向分化潜能的成体干细胞。MSCs参与免疫抑制并具有免疫原性低和向炎症及肿瘤区域迁移的能力等特性，可作为细胞载体用于肿瘤和自身免疫性疾病的靶向治疗而备受关注。然而，个体来源的MSCs数量有限，在体外扩增中分化潜能及增殖能力的衰减也限制了其临床应用。近年来人诱导多能干细胞(iPSCs)因其具有无限的增殖和分化潜能而展示了广泛的应用前景，源自患者自体iPSCs的MSCs已被用于癌症的自体细胞治疗。因此，该课题组尝试建立高效稳定表达抗癌因子的病人特异性ipsCs，诱导分化为MSCs用于肿瘤的自体化基因治疗。
研究人员通过构建携带白介素24(IL24)基因的新型rDNA区打靶载体pHrn-IL24，借助自主研发针对多拷贝位点显着降低细胞毒性和脱靶效应的人工核酸切口酶TALENickase，将IL-24高效整合到人尿液细胞来源iPSCs的多拷贝rDNA区。随后通过优化方法将定点整合IL24的iPSCs分化成MSCs(IL24-iMSCs)，并且检测到外源IL24在细胞中有效表达。在与黑色素瘤细胞体外共培养和小鼠体内共注射的实验中显示，IL24-iMSCs具有诱导肿瘤细胞凋亡和抑制肿瘤生长的功能。研究结果首次证明通过非病毒基因打靶病人特异性iPSCs获得自体MSCs用于癌症治疗的可行性，展示了基因编辑ipsCs在肿瘤自体化基因治疗领域的临床应用前景。
梁德生教授课题组长期致力于非病毒基因打靶研究，在自体干细胞核糖体基因(rDNA)区打靶应用于遗传病基因治疗研究方面取得了系列原创性成果，这是首次将该策略应用于肿瘤的靶向基因治疗研究。
原文链接：Enhanced tumor growth inhibition by mesenchymal stem cells derived from ipsCs with targeted integration of interleukin24 into rDNA loci
原文摘要：Induced pluripotent stem cells (iPSCs) are a promising source of mesenchymal stem cells (MSCs) for clinical applications. In this study， we transformed human iPSCs using a non-viral vector carrying the IL24 transgene pHrn-IL24. PCR and Southern Blotting confirmed IL24 integration into the rDNA loci in four of 68 iPSC clones. We then differentiated a high expressing IL24-iPSC clone into MSCs (IL24-iMSCs) that showed higher expression of IL24 in culture supernatants and in cell lysates than control iMSCs. IL24-iMSCs efficiently differentiated into osteoblasts， chondrocytes and adipocytes. Functionally， IL24-iMSCs induced in vitro apoptosis in B16-F10 melanoma cells more efficiently than control iMSCs when co-cultured in Transwell assays. In vivo tumor xenograft studies in mice demonstrated that IL24-iMSCs inhibited melanoma growth more than control iMSCs did. Immunofluorescence and histochemical analysis showed larger necrotic areas and cell nuclear aggregation in tumors with IL24-iMSCs than control iMSCs， indicating that IL24-iMSCs inhibited tumor growth by inducing apoptosis. These findings demonstrate efficient transformation of ipsCs through gene targeting with non-viral vectors into a rDNA locus. The ability of these genetically modified MSCs to inhibit in vivomelanoma growth is suggestive of the clinical potential of autologous cell therapy in cancer.
