MicroRNA 221 (miR-221)

MicroRNA 221 (miR-221) is a small, non-coding RNA molecule approximately 20-24 nucleotides in length that functions as a post-transcriptional regulator of gene expression[3][1]. miR-221 is transcribed by RNA polymerase II, processed from a primary transcript to a precursor miRNA and then to a mature miRNA, which is incorporated into the RNA-induced silencing complex (RISC) to repress translation or destabilize target mRNAs[3]. miR-221 plays critical roles in cell proliferation, differentiation, apoptosis, angiogenesis, autophagy, and inflammatory responses, largely through silencing of tumor suppressor genes and cell cycle regulators (e.g., p27, p57, PTEN)[5][4][1]. Its aberrant expression is associated with a wide spectrum of malignancies and cardiovascular and inflammatory diseases[2][5][4]. miR-221 is actively studied as a therapeutic target and clinical biomarker, with antisense oligonucleotides and combination therapies under preclinical and early clinical investigation[2][4][5]. Detection of miR-221 in body fluids is gaining interest as a non-invasive diagnostic, prognostic, and monitoring tool in oncology and beyond[1][4][6].

Other names

MIR221hsa-mir-221MIRN221miRNA221mir-221

Antisense inhibition: Blocking miR-221 function with oligonucleotides prevents its silencing of tumor suppressor genes[4]. Drug combination: Synergistic anti-tumor effects when combining antisense miR-221 agents with certain chemotherapeutics (e.g., sunitinib)[4]. Downregulation: Drugs like metformin may reduce miR-221 levels, restoring apoptosis and cell cycle arrest mechanisms[4].