Circulating MicroRNAs as Potential Predictors of Anthracycline-Induced Troponin Elevation in Breast Cancer Patients: Diverging Effects of Doxorubicin and Epirubicin

Abstract

Anthracyclines are anti-neoplastic drugs presenting cardiotoxicity as a side effect. Cardiac troponins (cTn) and echocardiography are currently used to assess cardiac damage and dysfunction, but early biomarkers identifying patients in need of preventive treatments remain a partially met need. Circulating microRNAs (miRNAs) represent good candidates, so we investigated their possible roles as predictors of troponin elevation upon anthracycline treatment. Eighty-eight female breast cancer patients administered with doxorubicin (DOX) or epirubicin (EPI) were divided into four groups basing on drug type and cTn positive (cTn+) or negative (cTn-) levels: DOX cTn-, DOX cTn+, EPI cTn- and EPI cTn+. Blood was collected at baseline, during treatment, and at follow-up. We identified plasma miRNAs of interest by OpenArray screening and single assay validation. Our results showed miR-122-5p, miR-499a-5p and miR-885-5p dysregulation in DOX patients at T0, identifying a signature separating, with good accuracy, DOX cTn- from DOX cTn+. No miRNAs showed differential expression in EPI subjects. Conversely, an anthracycline-mediated modulation (regardless of cTn) was observed for miR-34a-5p, -122-5p and -885-5p. Our study indicates specific circulating miRNAs as possible prediction markers for cardiac troponin perturbation upon anthracycline treatment. Indeed, our findings hint at the possible future use of plasma miRNAs to predict the cardiac responsiveness of patients to different anticancer agents.

Keywords: anthracyclines; biomarkers; microRNA.

Figure 1

Flow chart of the study. CT: chemotherapy; LV, left ventricle; HF, heart failure; EKG: electrocardiogram.

Figure 2

Experimental design. Eighty-eight breast cancer patients were enrolled and treated with doxorubicin (DOX) or epirubicin (EPI). Thick black vertical bars indicate experimental time-points when echocardiography was performed and blood samples collected.

Figure 3

Differential expression of DOX plasma miRNAs. (A) Three miRNAs, miR-122-5p, -499a-5p and -885-5p, showed modulated expression in DOX cTn+ vs. DOX cTn− patients at baseline. Data are depicted as box-and-whisker plots and expressed as max, median and min. (n = 14 DOX cTn−; n = 18 DOX cTn+; n = 44 EPI cTn−; n = 12 EPI cTn+). (B) Time course of miR-122-5p, -499a-5p and -885-5p, showing modulated expression in cTn+ vs. cTn− DOX patients at baseline but not at T1 and T2. Vertical bars represent the mean of −ΔΔCT ± SEM. Blue, cTn− DOX; Red, cTn+ DOX. (n = 14 DOX cTn−; n = 18 DOX cTn+). DOX, doxorubicin; miRNAs, microRNAs; EPI, epirubicin; cTn−, negative troponin levels; cTn+, positive troponin levels; −ΔΔCT, –delta-delta Ct; SEM, standard error of the mean.

Figure 4

Baseline plasma miRNA-based identification of DOX-cTn+ and DOX-cTn− patients. 3D scatterplots (left) and ROC analyses (right) were used to investigate whether the DOX-related plasma miRNA expression at baseline could be used to correctly separate cTn+ from cTn− patients. The AUC assesses the performance of the logistic model built, taking into account miR-499a-5p, miR-885-5p and miR-122-5p. Blue: cTn−. Red: cTn+. AUC: area under the curve.

Figure 5

Circulating miRNAs modulated upon anthracycline treatment. Time course for miR-34a-5p, -122-5p and -885-5p showing modulated expression in DOX (red) and EPI (green) patients. Vertical bars represent mean –ΔΔCT ± SEM. Green, DOX; Orange, EPI. * p < 0.05; ** p < 0.01; *** p < 0.001.

Figure 6

Circulating miRNAs as Anthracyclines Chemotherapy decision-makers. Flow chart of the possible use of plasma miRNA assessment at baseline to help clinicians in selecting drugs with the lowest cardiotoxicity risk and/or deciding whether to start cardioprotective preventive therapies.