Empagliflozin restores autophagy and ameliorates ponatinib-induced cardiomyocyte death

Abstract Background The tyrosine kinase inhibitor ponatinib has proven cardiovascular toxicity, for which no counteractive treatment is available at the moment. Sodium-glucose cotransporter type 2 (SGLT-2) inhibitors are approved drugs treat patients with chronic heart failure of different aetiologies. They play direct anticancer activity in SGLT2-expressing cancer cells, independent of glucose metabolism and through inhibition of oxidative phosphorylation. Ongoing studies are now testing empagliflozin (EMPA) in the prevention of left ventricular dysfunction in patients receiving high cumulative doses of anthracyclines. Aims To determine the effect of EMPA on cardiomyocytes in an in vitro model of PON-induced cardiac toxicity, and to assess underlying cardioprotective mechanisms. Methods and Results We exposed cardiomyocytes to PON (1.7 nM) or vehicle (DMSO) in the presence or absence of EMPA (100 and 500 nM) for 24 hours. Compared with vehicle, incubations with PON significantly reduced cell viability at 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, decreased autophagic cells at immunofluorescence assay (1±0.5 vs 6±1 fluorescence intensity/total area, p=0.0006, Figure 1), and increased cell senescence (15±5 vs 4±2 β-gal positivity/tissue area, p<0.02), effects all reverted by EMPA (p<0.01). We observed no significant effects of PON or EMPA on formation of reactive oxygen species. Compared with vehicle, PON significantly reduced serum response factor (SRF)/serum response elements (SRE) binding activity (25±9 vs 218±15 SRE complex abundance, arbitrary units, p<0.001), in parallel with a reduction in cardiac actin expression (0.32±0.06 vs 0.98±0,12 cardiac actin/GAPDH ratio, arbitrary units, p=0.001), which was reversed by EMPA (p=0.001). Conclusion EMPA attenuates PON cardiotoxicity by reducing senescence and enhancing autophagy, apparently independent of antioxidant mechanisms. This study suggests the design of clinical studies aimed at assessing the effects of EMPA on PON-induced cardiotoxicity.Legend to Figure 1.CON, control (vehicle, DMSO); PON, ponatinib; EMPA 100, empagliflozin 100 nM; EMPA 500, empagliflozin 500 nM