Clinically applicable human adipose tissue-derived mesenchymal stem cells delivering therapeutic genes to brainstem gliomas

Pediatric brainstem glioma is an incurable malignancy because of its inoperability. As a result of their extensive tropism toward cancer and the possibility of autologous transplantation, human adipose-derived mesenchymal stem cells (hAT-MSC) are attractive vehicles to deliver therapeutic genes to brainstem gliomas. In this study, in a good manufacturing practice (GMP) facility, we established clinically applicable hAT-MSCs expressing therapeutic genes and investigated their therapeutic efficacy against brainstem glioma in mice. For feasible clinical applications, (1) primary hAT-MSCs were cultured from human subcutaneous fat to make autologous transplantation possible, (2) hAT-MSCs were genetically engineered to express carboxyl esterase (CE) and (3) a secreted form of the tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) expression vector for synergistic effects was delivered by a gene transfer technology that did not result in genomic integration of the vector. (4) Human CE and sTRAIL sequences were utilized to avoid immunological side effects. The hAT-MSCs expressing CE +/- sTRAIL showed significant therapeutic effects against brainstem gliomas in vitro and in vivo. However, the simultaneous expression of CE and sTRAIL had no synergistic effects in vivo. The results indicate that non-viral transient single sTRAIL gene transfer to autologous hAT-MSCs is a clinically applicable stem cell-based gene therapy for brainstem gliomas in terms of therapeutic effects and safety.