miR221/222 in Cancer: Their Role in Tumor Progression and Response to Therapy

M.      Garofalo; C.      Quintavalle; G.      Romano; C.      M. Croce; G.      Condorelli

Abstract

miRNAs are small non-coding RNAs of ~24 nt that can block mRNA translation and/or negatively regulate its stability. There is a large body of evidence that dysregulation of miRNAs is a hallmark of cancer. miRNAs are often aberrantly expressed and their function is linked to the regulation of oncogenes and/or tumor suppressor genes involved in cell signaling pathway. miR-221 and miR-222 are two highly homologous microRNAs, whose upregulation has been recently described in several types of human tumors. miR-221/222 have been considered to act as oncogenes or tumor suppressors, depending on tumor system. Silencing oncomiRs or gene therapy approaches, based on re-expression of miRNAs that are down-regulated in cancer cells, could represent a novel anti-tumor approach for integrated cancer therapy. Here we will review the role of miR-221/222 in cancer progression and their use as prognostic and therapeutic tools in cancer.

Keywords: Cancer, cancer therpay, microRNA, transcription, Dicer, RNA-induced silencing complex (RISC), translation, genome, apoptotic pathways, metastasis, leukemia, lymphoma, hepatocellular carcinoma, oncogenes, oncosuppressor genes