MicroRNA-messenger RNA interactions involving JAK-STAT signaling genes in colorectal cancer

JAK-STAT signaling influences many downstream processes that, unchecked, contribute to carcinogenesis and metastasis. MicroRNAs (miRNAs) are hypothesized as a mechanism to prevent uncontrolled growth from continuous JAK-STAT activation. We investigated differential expression between paired carcinoma and normal colorectal mucosa of messenger RNAs (mRNAs) and miRNAs using RNA-Seq and Agilent Human miRNA Microarray V19.0 data, respectively, using a negative binomial mixed effects model to test 122 JAK-STAT-signaling genes in 217 colorectal cancer (CRC) cases. Overall, 42 mRNAs were differentially expressed with a fold change of >1.50 or <0.67, remaining significant with a false discovery rate of < 0.05; four were dysregulated in microsatellite stable (MSS) tumors, eight were for microsatellite unstable (MSI)-specific tumors. Of these 54 mRNAs, 17 were associated with differential expression of 46 miRNAs, comprising 116 interactions: 16 were significant overall, one for MSS tumors only. Twenty of the 29 interactions with negative beta coefficients involved miRNA seed sequence matches with mRNAs, supporting miRNA-mediated mRNA repression; 17 of these mRNAs encode for receptor molecules. Receptor molecule degradation is an established JAK-STAT signaling control mechanism; our results suggest that miRNAs facilitate this process. Interactions involving positive beta coefficients may illustrate downstream effects of disrupted STAT activity, and subsequent miRNA upregulation.