[1242] Mechanisms of Expression and Regulation of SOX2 and Its Targets in Two Embryonal Carcinoma Cell Lines

Sebastian Vencken, Michael F Gallagher, Gordon Blacksheilds, Cara Martin, Orla M Sheils, John J O'Leary. University of Dublin, Trinity College, Dublin, Ireland

Background: SOX2 is a conserved pluripotency-associated transcription factor considered to be crucial for embryonal stem cell (ESC) and embryonal carcinoma cell (ECC) maintenance. In addition to its ability to autoregulate its expression, it closely regulates the expression of a wide range of genes important to 'stemness' and is also activated in various types of cancer stem cells (CSCs). MicroRNA (miRNA) are short, non-coding RNAs of approximately 23 nucleotides in length. Their most important documented capability is the regulation gene expression post-transcriptionally by preventing the translation of specific target mRNAs.
Design: We silenced SOX2 in two human ECC lines, NTera-2 and 2102Ep, which resulted in the initiation of the differentiation program of these cell lines. After three days, whole-genome and whole-miRNAome expression was measured.
Results: Hundreds of genes were differentially deregulated in both cell lines, revealing pathways directly and indirectly regulated by SOX2. Besides a large overlap in differential gene expression of NTera-2 and 2102Ep cells, large discrepancies were also found, including in the expression of core pluripotency markers, POU5F1/OCT4 and NANOG. This could possibly indicate a difference in roles SOX2 plays in these cells. Compared to previous data from a third, widely used ECC line, NCCIT, 2102Ep showed a higher overlap with this cell line than NTera-2. Whole-miRNAome analysis revealed tens of differentially regulated miRNAs in both cell lines. Overlap was found but important discrepancies between NTera-2 and 2102Ep were also recorded, with the most notable difference being the downregulation of the C19MC polycistronic miRNA cluster in 2102Ep but not in NTera-2. This cluster has been associated with cancer and also with the differentiation program of ESCs. Our data indicates that members of this cluster could target various parts of the Wnt-signalling pathways, providing a possible novel mechanism through which SOX2 regulates cancer stemness and embryonic development.
Conclusions: Our results showed that SOX2 directly and indirectly regulates hundreds of genes and tens of miRNAs in ECCs, but has distinctive roles in different ECC types. The C19MC polycistron stood out from the results and could have novel implications in the regulation of Wnt signalling. Further analysis of this data and future research could reveal what these precise roles are.
Category: Gynecologic & Obstetrics

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 192, Wednesday Afternoon


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