MicroRNAs (miRNAs) are small non-coding RNA molecules, approximately 22 nucleotides in length that regulate gene translation through silencing or degradation of target mRNAs. They are involved in multiple biological processes, including differentiation and proliferation, metabolism, hemostasis, apoptosis or inflammation, and in pathophysiology of many diseases. Numerous studies have suggested circulating miRNAs as promising diagnostic and prognostic biomarkers of many diseases.
miR-9-5p is expressed in various cell types, first in the central nervous system during embryonic development, and later in macrophages, neutrophils, and tumor cells. The expression level of miR-9-5p has been shown to have an association with various human cancers including breast cancer, gastric cancer, pancreatic cancer and glioblastoma.
miR-9 could regulate the expression of E-cadherin, a prominent molecule responsible for cell adhesion, in breast cancer cells. The expression level of miR-9-5p significantly decreased in the tissues of gastric cancer in comparison with normal tissues. There was also a reduction in the expression level of miR-9-5p in the serum of gastric cancer patients. miR-9-5p was significantly downregulated in pancreatic cancer tissues and cell lines. The expression levels of miR-9-5p were negatively correlated with tumor stage and vessel invasion. Low expression of miR-9-5p was strongly correlated with poor overall survival in pancreatic cancer patients. Moreover, overexpression of miR-9-5p remarkably inhibited pancreatic cancer cell proliferation by enhancing cell apoptosis and significantly suppressed the invasion of pancreatic cancer cells. Increased expression of microRNA-9 predicts an unfavorable prognosis in human glioma. miR-9 can reduce cell migration and the invasion of glioblastoma cell lines through MAPK14 pathway.
miR-9-5p has been reported to be upregulated and closely related to collagen proteins in human dermal fibroblasts. MiR-9-5p suppressed proliferation and promoted apoptosis of hypertrophic scar fibroblasts by targeting peroxisome proliferator-activated receptor β (PPARβ). In patients with rheumatoid arthritis (RA) and peripheral neuropathy, serum miR-9-5p was significantly downregulated when compared with serum samples from patient with RA. A significantly negative correlation was observed between miR-9-5p and repressor element-1 silencing transcription factor REST.
- References to miR-9-5p