miR-224 is a family of microRNA precursors found in mammals, including humans. The ~22 nucleotide mature miRNA sequence is excised from the precursor hairpin by the enzyme Dicer.[1]
Function
miR-224, being located on the X-chromosome, is thought to be active in mammalian ovaries, and possibly responds to TGF beta 1.[2] A target of miR-224 has been predicted to be SMAD4. Experimental evidence has shown that while the SMAD4 mRNA level is unchanged, increased miR-224 expression decreases concentration of SMDA4 protein in murine granulosa cells.[3] This is consistent with post-transcriptional miRNA regulation.[2]
Role in cancer
miR-224 has been noted as the most upregulated microRNA in hepatocellular carcinoma.[4] The same study identified a target of mir-224 as apoptosis-inhibitor 5 (API-5).[4]
^Mees ST, Mardin WA, Sielker S, Willscher E, Senninger N, Schleicher C, Colombo-Benkmann M, Haier J (August 2009). "Involvement of CD40 targeting miR-224 and miR-486 on the progression of pancreatic ductal adenocarcinomas". Annals of Surgical Oncology. 16 (8): 2339–50. doi:10.1245/s10434-009-0531-4. PMID19475450. S2CID10583399.