2017 ACVIM Forum Research Abstract Program

Real time PCR demonstrated that miR-34a expression levels were significantly lower in primary canine OSA tumors and OSA cell lines compared to normal canine osteoblasts. Furthermore, miR-34a expression was found to be significantly decreased in distant metastases compared to primary OSA tumors, suggesting that loss of miR-34a is directly involved in the metastatic process. To address the effects of miR-34a on OSA cell behavior, the canine OSA8 and Abrams cell lines which express low basal levels of miR-34a were transduced with miR-34a lentiviral constructs resulting in high levels of miR-34a. In transformed canine OSA8 and Abrams cell lines, miR-34a overexpression reduced cellular invasion and migration but had no effect on cell proliferation or cell cycling. Transcriptional profiling of OSA8 cells overexpressing miR-34a demonstrated dysregulation of several genes, including down-regulation of putative miR-34a target genes associated with cellular invasion. Consistent with these findings, enhanced expression of these genes correlates with decreased miR-34a expression in primary canine OSA tumors.