Cardiotoxic effects of the novel approved anti-ErbB2 agents and reverse cardioprotective effects of ranolazine

Figure 1. In vitro cardiotoxic effects of anti-ErbB2 antibodies on cardiac cell lines. Notes: Western blotting analysis with the commercial anti-ErbB2 rabbit mAb of extracts from Cor.4U, HFC or H9C2 cells. To normalize the ErbB2 band signals, the ratio of actin signal intensities was calculated between the different cell extracts and found to be 1 for Cor.4U, 0.87 for HFC and 1.12 for H9C2 (A). Trastuzumab and pertuzumab binding to Cor.4U, SKBR3 (ErbB2-positive cells) and A431 (ErbB2-negative cells) were used as positive and negative controls, respectively (B). Effects of increasing concentrations of pertuzumab, trastuzumab or TDM1 (25, 50, 100 and 200 nM), as determined by MTT, on HFC (C), H9C2 (D) or Cor.4U (E) cell lines, respectively. *p<0.05. Abbreviations: DM1, emtansine; ErbB2, epidermal growth factor receptor 2; HFC, human fetal cardiomyocytes; mAb, monoclonal antibody; TDM1, trastuzumab-DM1.

Figure 2. Effects of anti-ErbB2 antibodies on cardiac cell morphology. Note: Effects of trastuzumab, pertuzumab, TDM1 or doxorubicin (200 nM) on the morphology of HFC and Cor.4U cell lines after 72 hours of treatment were determined by light microscopy (magnification 1:20). Abbreviations: DM1, emtansine; ErbB2, epidermal growth factor receptor 2; HFC, human fetal cardiomyocytes; TDM1, trastuzumab-DM1.

Figure 3. In vitro cardioprotective effects of Ran for anti-ErbB2–associated cardiotoxicity on H9C2 and HFC cell lines. Notes: Cardioprotective effects of Ran (10 μM) were tested by trypan blue exclusion test after treatment in the absence or in the presence of 200 nM of trastuzumab (A), pertuzumab (C) or TDM1 (E) on H9C2 cell line. Cardioprotective effects of Ran (10 μM) were also measured in the absence or in the presence of trastuzumab (B), pertuzumab (D) or TDM1 (F) on HFC cells. *p<0.05. Abbreviations: DM1, emtansine; ErbB2, epidermal growth factor receptor 2; HFC, human fetal cardiomyocytes; Ran, ranolazine; TDM1, trastuzumab-DM1.

Figure 4. In vitro cardioprotective effects of Ran for anti-ErbB2–associated cardiotoxicity on human adult cardiomyocytes. Notes: Cardioprotective effects of Ran (10 μM) were tested in the absence or the presence of 200 nM TDM1 (A), doxorubicin (B), trastuzumab (C) or pertuzumab (D) on Cor.4U cell line. *p<0.05. Abbreviations: DM1, emtansine; ErbB2, epidermal growth factor receptor 2; Ran, ranolazine; TDM1, trastuzumab-DM1.

Figure 5. In vivo cardioprotective effects of Ran in the cardiotoxic side effects of TDM1. Notes: Effects of TDM1 on FS and EF of mice treated for 5 days (TDM1), followed by the effects posttreatment with either saline solution (control) or Ran (dark gray). *p<0.05. Abbreviations: DM1, emtansine; EF, ejection fraction; FS, fractional shortening; Ran, ranolazine; TDM1, trastuzumab-DM1.