Gene expression analyses of mir-22 overexpression in ovarian clear cell cancer cell line

A variety of human cancers demonstrate alterations in microRNA expression. We hypothesized that regulatory defects in microRNAs play a central early role in organizing the molecular changes involved in ovarian cancer (OvCa). Using both gene arrays and deep sequencing, we comprehensively profiled mRNA and microRNA expression, respectively, in human clear cell epithelial OvCa cell lines and short-term primary cultures of normal ovarian surface epithelium. We expected that over-expression of a specific microRNA would lead to lower expression of its mRNA targets, and under-expression of a specific microRNA would lead to higher expression of its target genes. Using our expression data in conjunction with established in silico algorithms, we found putative microRNA:mRNA functional pairs. Furthermore, gene expression profiles were taken of clear cell cultures having functional knockdown or over-expression of specific microRNAs of interest. Knockdown of mir-22 (found under-expressed in clear cell OvCa) resulted in down-regulation in vitro of a significant number of the in silico predicted mir-22 target genes that were normally over-expressed in OvCa.

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Nagaraja AK, Creighton CJ, Yu Z, Zhu H, Gunaratne PH, Reid JG, Olokpa E, Itamochi H, Ueno NT, Hawkins SM, Anderson ML, Matzuk MM