Definition

A phosphorothioate (PS) modified backbone 13-mer locked nucleic acid (LNA)-based antisense oligonucleotide (ASO) and inhibitor of the oncogenic microRNA (miRNA) miR-221, with potential chemo-sensitizing and antineoplastic activities. Upon administration, miR-221 LNA inhibitor LNA-i-miR-221 hybridizes with endogenous miR-221 and inhibits miR-221-mediated functions involving tumor cell proliferation, angiogenesis and metastasis, and the modulation of drug influx-efflux transporters as it regulates the expression of a variety of target genes. miR-221, oncogenic miRNA that is upregulated in various malignancies, plays important roles in tumor cell proliferation, angiogenesis and metastasis, and in the development of drug resistance such as melphalan resistance.