Title:
Generation of Human iPS cells for therapeutic treatment

Keisuke Okita Ph.D. Lecturer
Department of Reprogramming Science, Center for iPS Cell Research and Application, Kyoto University

Abstract:
Reprogramming of somatic cells into pluripotent stem cells has been reported by introducing a combination of several transcription factors, such as Oct3/4, Sox2, Klf4, and c-Myc. The induced pluripotent stem (iPS) cells from patient’s somatic cells would be useful source for drug discovery and cell transplantation therapies. However, most human iPS cells were made by retrovirus vectors, which integrate the reprogramming factors into host genomes and may increase tumor formation risk. In fact, activation of c-Myc transgene resulted in tumor formation in mouse model. To overcome the safety concern of iPS cell generation, several non-integration methods have been reported, such as transient expression of the reprogramming factors using sendaivirus vectors or plasmids, and direct delivery of synthetic RNAs. On the other hand, recent studies have uncovered the differences between iPS cells and ES cells in terms of gene expression, epigenetic modification, and differentiation potentials. Tissue origin also affects the quality of iPS cells. Further improvements in the generation method are needed, not only in safety aspects, but also in quality, before they can be medically applied.