P4763Circulating microRNAs as selective markers of anthracyclines-based therapies in breast cancer patients

Abstract

Background: The main adverse effect of Anthracyclines, which are highly effective anti-neoplastic drugs, is their cardiotoxicity, leading to progressive heart dysfunction. Assessment of cardiac impairment is usually accomplished by echocardiography, while evaluation of current circulating biomarkers can only give an indication of either initial tissue damage (cardiac troponins) or overt heart failure (natriuretic peptides). Thus, a new class of early diagnostic biomarkers is needed to help assess a possible future dysfunction onset. Recently, circulating microRNAs (miRNAs), small non-coding RNAs with regulatory functions, have been proposed as biomarkers of cardiovascular disease. Purpose: The aim of this work was the identification of plasma miRNAs that may serve as early prediction tools of anthracycline-induced cardiotoxicity in breast cancer patients receiving either doxorubicin (dox) or epirubicin (epi) treatment. Methods: Ninety-four female patients with breast cancer treated with anthracyclines were enrolled in this study. In particular, 37 patients received doxorubicin and 57 epirubicin. Subjects were stratified as cases (dox n=20, epi n=12) and controls (dox n=17, epi n=45) based on the presence or absence of an increase in troponin plasma levels, respectively, at any time during or following treatment. Blood was collected at three time points: baseline (before treatment, T0), short follow-up (one month after last infusion, T1), and long follow-up (three months after last infusion, T2). RNA-sequencing was conducted on plasma samples from four randomly selected 6 cases and 6 controls (T0, T1, T2), in order to identify differentially expressed miRNAs. Validation of miRNAs of interest was conducted on all samples by RT-qPCR using TaqMan based single miRNA assays. Statistical analysis was conducted using multiple comparisons test (e.g. two-way ANOVA) as appropriate. Results: Our data showed an anthracycline-induced modulation for 4 miRNAs: miR-34a, miR-122, miR-376c-3p, and miR-499a-5p. Among them, the first three presented a significant up-regulation at every time points vs. T0, regardless of the administered drug (p<0.05). Interestingly, when focusing on the T0, miR-122 and miR-499a-5p showed (see figure) a higher expression in cases vs. control only in the doxorubicin groups (p<0.05). Differently, no epirubicin-specific miRNA modulation was observed at any time. Conclusions: This is the first study indicating the potential of specific circulating miRNAs as prediction markers of doxorubicin-induced cardiotoxicity. Although no similar results were obtained for epirubicin, these findings could pave the way to the future identification of miRNAs-based specific diagnostic signatures of cardiotoxicity in anthracycline-based therapies.