MicroRNA 503 (miR-503)

MicroRNA 503 (miR-503) is a short, non-coding RNA (microRNA) encoded by the MIR503 gene located on chromosome X in humans. Like other microRNAs, miR-503 regulates gene expression at the post-transcriptional level by binding to complementary sequences in target messenger RNAs (mRNAs), commonly resulting in translational repression or mRNA degradation. miR-503 is a member of the miR-15/16 family and is transcribed in a cluster with miR-424, often participating in the induction of cell cycle arrest and inhibition of cell proliferation. miR-503 exhibits tissue- and disease-specific expression, playing tumor-suppressive roles in several cancer types (such as glioblastoma, hepatocellular carcinoma), but can act oncogenically in others (for example, retinoblastoma). In the cardiovascular system, miR-503 participates in endothelial function, angiogenesis inhibition, and cardiac fibrosis. Its dysregulation has been linked to cancer progression, metastasis, cardiac fibrosis, and serves as a biomarker for disease prognosis in multiple malignancies. Therapeutic modulation of miR-503 (by inhibition or supplementation) is under preclinical investigation for cancer and cardiovascular indications.

Other names

MIR503miR-503hsa-mir-503mmu-mir-503 (for mouse)

AntagomiRs: Bind and inhibit miR-503, thereby derepressing its gene targets; miRNA mimics: Restore or enhance miR-503 function by supplementing endogenous levels