Artificial Reprogramming of Human Somatic Cells to Generate Pluripotent Stem Cells: A Possible Alternative to the Controversial Use of Human Embryonic Stem Cells

Recent findings showed certain specific factors had the ability to reprogram in vitro human somatic cells, which in turn could generate pluripotent stem cells. Remarkably, somatic cell-derived pluripotent stem cells recapitulated the features of human embryonic stem cells, as demonstrated independently by two groups of investigators. The reprogramming of somatic cells may represent an alternative to the controversial use of human embryonic stem cells in transplantation therapy and in a variety of other applications, such as generation of cellular models for human diseases and for drug research and development. However, the intrinsic expression of epigenetic reprogramming factors in somatic cells requires the use either of lentiviral- or retroviral-mediated gene transfer, which may cause insertional mutagenesis-induced malignancies. In summary, the recent achievements for the in vitro reprogramming of human somatic cells to a pluripotent state can be considered an important advancement in stem cell research. As for future clinical applications in regenerative medicine, it is necessary to tackle the issue of insertional mutagenesis, which is associated with all types of integrating gene delivery systems. Another critical issue is the control of the tumorigenic potential of somatic cell-derived pluripotent stem cells. As it stands, the newly developed technology can be used to engineer useful models for the study of human diseases and development of novel therapeutics.