as clusters of genes implicated in cell trafficking and differentiation. Thus, some populations of MSC appeared to be more permissive than others for SYT-SSX-induced changes in the expression of genes relevant to fundamental requirements for normal and cancer stem cell biology. Similarly, single population analysis revealed greater similarity of some MSCSYT-SSX1 population transcriptomes than others to SS gene expression signatures, MCE Company AZD-9668 supporting the hypothesis that features which distinguish independent hMSC isolates and contribute to their heterogeneity may be key for SYT-SSX function. Our present observations suggest that the nature of these putative features may, at least in part, be epigenetically determined. Transcriptome analysis of hMSCSYT-SSX1 showed that a major effect of SYT-SSX in hMSCs involves changes in the expression of epigenetically regulated genes, including imprinted genes, genes that contain CpG island in their TSS and chromatin related genes. Epigenetic de-regulation has been suggested to be a central effect of the aberrant expression of SYT-SSX and a possible mechanism underlying synovial 916151-99-0 sarcoma formation. The present transcriptome analysis of hMSC expressing SYT-SSX strongly supports this notion. Consistent with the variability of MSCSYT-SSX1 transcriptome relatedness to SS signatures and that of GO term overrepresentation, single population analysis limited to datasets of epigenetically regulated genes showed marked qualitative and quantitative differences among the four hMSC isolates, the most striking being the divergent effect of SYT-SSX on the expression of imprinted genes. It is therefore conceivable that epigenetic features displayed only by some hMSC populations permit SYT-SSX to affect expression of genes implicated in biological functions relevant to stem cells and SS. We therefore sought divergent epigenetic characteristics among the MSC populations that may explain the significant variations observed in the transcriptional effect of SYT-SSX. Assessment of the H19/IGF2 cluster provided support for our hypothesis. IGF2 is considered to be one of the signature genes of SS and is part of one of the best characterized imprinted clusters. Deregulation of its expression has been sugg
