Enhanced tumor growth inhibition by mesenchymal stem cells derived from iPSCs with targeted integration of interleukin24 into rDNA loci

// Bo Liu 1 , Fei Chen 1 , Yong Wu 1 , Xiaolin Wang 1 , Mai Feng 1 , Zhuo Li 1 , Miaojin Zhou 1 , Yanchi Wang 1 , Lingqian Wu 1 , Xionghao Liu 1 and Desheng Liang 1 1 The State Key Laboratory of Medical Genetics and School of Life Sciences, Central South University, Changsha, China Correspondence to: Desheng Liang, email: liangdesheng@sklmg.edu.cn Xionghao Liu, email: liuxionghao@sklmg.edu.cn Keywords: rDNA locus, gene targeting, MSCs derived from iPSCs, IL24, anti-tumor Received: August 17, 2016      Accepted: March 13, 2017      Published: March 28, 2017 ABSTRACT 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 vivo melanoma growth is suggestive of the clinical potential of autologous cell therapy in cancer.