Recruitment of cancer stemness signature miRNAs during recurrence Having identified gene level overlaps, we next conducted overlap meta analysis of our previously published miRNA data for primary and recurrent patient samples and human EC early differentiation. The earlier study identified cancer stemness signature miRNAs, those miRNAs involved in the differentiation of hEC cells. Specifically, our previous tumor study high lighted 60 miRNAs in recur rent disease. Of these, 55 miRNAs are expressed in hEC cells. 21 recurrent disease speci fic miRNAs are linked to differentiation of pluripotent NTera2 hEC cells. We have previously shown that nullipotent 2102Ep hEC cells express a large number of miRNAs at substantially higher levels than NTera2 cells.

Here we report that 26 recurrent disease speci fic miRNAs are expressed at higher levels in 2102Ep cells than in NTera2. Thus, development of recurrent tumors involves recruitment of cancer stemness signature miRNAs. Specific examples include miR 9, which is the most downregulated miRNA in recurrent tumors this article and is 1000% higher expressed in undifferentiated 2102Ep cells compared to NTera2, and miR 206, which is in the top ten miRNAs upregulated by recurrent tumors and down regulated during NTera2 differentiation. Molecular path way relationships between predicted gene targets of the miRNAs highlighted were identified using DIANAmir PATH. While little pathway overlap was observed in gene array data, miRNA data showed strong pathway associations. Pathway analysis highlighted alteration of several cancer pathways as well as Wnt and TGF b stemness signaling pathways.

Finally, we assessed the expression of p53 p21 regulating miRNAs read what he said in these datasets. Two miRNAs, miRs 106a and b, are validated targets of p21 that are upre gulated in recurrent disease and expressed in hEC cells. Notably, miR 106b expression in 2102Ep cells is double that of NTera2 cells. In contrast, miR 155, the only vali dated p53 regulating miRNA, is unaltered in recurrent tumors. We note that the p53 signaling pathway was high lighted for let 7g and miRs 106b and 107 in pathway ana lysis. In overview, we find that miRNAs linked to 2102Ep malignancy are highly relevant to pri mary and recurrent tumors. Discussion Although CSCs are obvious suspects in the development of recurrent ovarian malignancy, a relationship has yet to be established or described in detail. Anecdotal evidence includes altered regulation of Notch3 in chemoresistant ovarian disease and the clear parallel between epithelial mesenchymal transition and CSC differentiation mechanisms. In this study we conducted microar ray and meta analysis of mRNA and miRNA expression in primary and recurrent tumor samples and an EC model of cancer stemness.