Meeting report: stem cell biology and epigenetics

Abstract

The Genetics Society of Korea (GSK) had a symposium in the 68th Annual Meeting of the Korean Association of Biological Sciences (KABS) that was held during August 12–13 at Sogang University, Seoul, Korea. The symposium had two sessions on the two frontier fields in genetics; stem cell biology and epigenetics. The first session was on the stem cell biology that covered from the basics of the stem cell research to progresses in therapeutic approaches. Three active scientists presented their recent findings. The first speaker was Professor Dong Wook Han at the Konkuk University, Korea, with a title of ‘‘Inducing different stem cell fates by defined factors’’. Because the audience consists of diverse fields in genetics, he began his talk with nice introduction on the definition and sources of the stem cells. Recent advances in stem cell research have revealed that cell-type specific transcription factors can rest the somatic memory of differentiated cells and induce direct reprogramming into specific cell identity. The most remarkable achievement is that a combination of neural-specific transcription factors can induce a neural stem cell (NSC) fate on the fibroblasts. The experimental results showed that the induced neural stem cells (iNSCs) were similar to the wild type NSCs in cell morphology, gene expression, epigenetic features, differentiation potential, and cellular function. Thus, he posited that cell type-specific defined factors can induce specific stem cell identities from somatic cells. He also introduced his recent findings on the direct conversion of differentiated somatic cells into specific cellular identities such as hepatocytes. The second speaker professor, Hyuk-Jin Cha, at the Sogang University, Korea, gave a talk with a title of ‘‘Inhibition of pluripotent stem cell derived teratoma formation by small molecules’’. One of the obstacles in therapeutic application of the stem cells is the removal of residual undifferentiated pluripotent stem cells (PSCs) after differentiation. Because the undifferentiated PSCs can proliferate unlimitedly to form a tumor mass, it is critical to sort completely out the residual undifferentiated PSCs for tumor-free cell therapy. Several approaches have been suggested to eliminate the remaining undifferentiated cells, including the introduction of suicide gene, immunedepletion and introducing cytotoxic antibodies. However, the rigorous sorting techniques are still far behind in isolating the differentiated cells purely and have yet reached at the level of clinically viable strategy to eliminate teratoma formation. PSCs are highly susceptible to apoptotic stimuli such as reactive oxygen species and DNA damage stress which can induce genetic alteration to the differentiated cells. Thus, high responsiveness to apoptosis can be considered to be one of the protective mechanisms to retain genetic integrity during differentiation. Dr. Cha’s group analyzed the proand anti-apoptotic genes in human PSCs (hPSCs) and found that 22 pro-apoptotic genes and 10 antiapoptotic genes were highly expressed in undifferentiated PSCs. Of interest, inhibition of two anti-apoptotic factors (BIRC5 and BCL10) by small molecule could significantly induce selective cell death of PSCs but not differentiated J.-K. Lee Department of Biology Education, Seoul National University, Seoul 152-742, Korea