Abnormally expressed long noncoding RNAs (lncRNAs) has been recognized as one of the key source in cardiac diseases. However, the role of lncRNA in doxorubicin (DOX)-induced cardiotoxicity remains largely unknown. In previous studies, we have screened some aberrantly expressed lncRNAs from an animal model for DOX-induced cardiotoxicity, and LINC00339 is one of the highly expressed lncRNA. In this study, we validated and further explored its regulatory mechanisms using in vitro model systems. Primary cultured myocardial cell (PC) and H9C2 cell line were treated with different concentrations of DOX and the expression of LINC00339 were markedly up-regulated. However, knockdown of endogenous LINC00339 by its siRNA improved cells proliferation activity and reduced cardiomyocyte apoptosis. Further experiments showed the opposite trend of expression between LINC00339 and miR-484. Bioinformatics analysis and luciferase reporter assay indicated that LINC00339 directly binds to miR-484. Moreover, miR-484 inhibitor abrogated the collagen synthesis inhibition induced by LINC00339. These findings reveal a novel function of the LINC00339/miR-484 axis in DOX-induced cardiotoxicity. (C) 2018 Elsevier Inc. All rights reserved.