Expression Profiling of microRNAs hsa-222-3p, hsa-let-7b-5p, hsa-let-7f-5p and their Putative Targets HMGA1 and CDKN1B Genes in Canine Mammary Tumor

Cancer is unregulated growth of cells that can spread to other part of body via blood circulation and lymphatic system. Mutations in genetic material can alter cell physiology, ultimately resulting in tumor. Like human cancers, dogs have relatively high incidence of cancers, relatively large body size and responses to cytotoxic and other therapeutics. Small noncoding RNA having length of 22 base pair (bp) are called micro-RNA (miRNA), that are processed by Dicer from precursors with a characteristic hairpin secondary structure. miRNAs can regulate gene expression at the post-transcriptional level by binding to the 3 ' untranslated region (UTR) of target mRNAs. In this study dog mammary tumor samples were collected to investigate the expression level of miRNAs hsa-222-3p, hsa-let-7b-5p and hsa-let-7f-5p and effect of their expression on the target genes (HMGA1 and CDKN1B) of these miRNAs. Qiagen miScript Primer Assay based expression analyses revealed the over-expression of all three miRNAs in most of the studied canine mammary tumor samples compared to normal mammary tissue. Furthermore, this over-expression of tested miRNAs, down regulated their target genes in tumor samples compared to normal samples.