The Cardiotoxic Mechanism of Doxorubicin (DOX) and Pegylated Liposomal DOX in Mice Bearing C-26 Colon Carcinoma: a Study Focused on microRNA Role for Toxicity Assessment of New Formulations.

PURPOSE

MicroRNAs (miRs) are a group of small non-coding RNAs that regulate transcriptional or post-transcriptional gene expression. The aim of the present study was to investigate the role of miR -1, -21 and -145 and their targets in cardiotoxicity-induced by DOX and pegylated liposomal DOX.

METHODS

BALB/c mice subjected to subcutaneous injection of C-26 tumor cells. Eight days after tumor inoculation, animals were divided into 6 groups: control, liposome, DOX (6 and 9 mg/kg) and PL-DOX (6 and 9 mg/kg). The formulations were administered one time per week for four weeks. 24 h after the last injection, mice were sacrificed; blood and heart samples were taken. Western blot analysis was done on protein extracts to investigate the expression of cardiac caspase-3, -8, Bax, Bcl2, Programmed cell death 4 (PDCD4) and BCL2/Adenovirus E1B 19 kDa Interacting Protein 3 (BNIP3). The expression levels of miR -1, -21 and -145 were also evaluated by quantitative real-time PCR.

RESULTS

Mice treated with both DOX formulations showed a marked inhibition in tumor growth. Western blot analysis indicated that the expression level of cardiac caspase-3, caspase-8, Bax and BNIP3 were up-regulated due to DOX injection (9 mg/kg). Exposure of mice with DOX resulted in a significant increase in cardiac miR-1 and miR-21 expression level. PL-DOX treatment did not change the proteins and miRs expression.

CONCLUSION

The results suggest that miR -1, -21 and -145 may involve in cardiotoxicity induced by DOX. Evaluation of miRs signaling pathways might be of potential value for toxicity assessment of new formulations. Graphical Abstract The cardiotoxic mechanism of doxorubicin (DOX) and pegylated liposomal DOX (PL-DOX).