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-136-5p may play different roles in various types of human cancer; its aberrant expression is associated with tumorigenesis, metastasis, and cancer progression. It has been found that miR-136-5p acts as tumor suppressor and its deficiency induces chemoresistance in ovarian cancer. Another study showed that miR-136-5p might act as a negative regulator in colon cancer progression. Expression of miR-136-5p in osteosarcoma tissues and cell lines was dramatically decreased compared with corresponding noncancerous tissues and cell lines, respectively. In hepatocellular carcinoma, downregulation of miR-136-5p may be responsible for carcinogenesis and aggressiveness of the disease.
In contrast, miR-136-5p acts as oncogene in non-small cell lung cancer and is upregulated in lung cancer tissue and cell lines compared to their non-cancerous counterparts. Expression of miR 136-5p was also shown to be aberrantly upregu¬lated in gastric cancer tissues and cell lines and suppression of miR 136-5p inhibited proliferation and invasion in gastric cancer cell lines.
Decreased plasma miR 136 levels were measured in knee osteoarthritis patients when compared to healthy controls. Significantly higher expression levels of miR-136-5p in exosomes were observed in patients with preeclampsia compared to normal pregnancies.
- References to miR-136-5p