Sunitinib-induced cardiac hypertrophy and the endothelin axis

Abstract

Anti-angiogenics drugs in clinical use for cancer treatment induce cardiotoxic side effects. The endothelin axis is involved in hypertension and cardiac remodelling, and addition of an endothelin receptor antagonist to the anti-angiogenic sunitinib was shown to reduce cardiotoxicity of sunitinib in mice. Here, we explored further the antidote effect of the endothelin receptor antagonist macitentan in sunitinib-treated animals on cardiac remodeling. Methods: Tumor-bearing mice treated per os daily by sunitinib or vehicle were imaged before and after 1, 3 and 6 weeks of treatment by positron emission tomography using [¹⁸F]fluorodeoxyglucose and by echocardiography. Non-tumor-bearing animals were randomly assigned to be treated per os daily by vehicle or sunitinib or macitentan or sunitinib+macitentan, and imaged by echocardiography after 5 weeks. Hearts were harvested for histology and molecular analysis at the end of in vivo exploration. Results: Sunitinib treatment increases left ventricular mass and ejection fraction and induces cardiac fibrosis. Sunitinib also induces an early increase in cardiac uptake of [¹⁸F]fluorodeoxyglucose, which is significantly correlated with increased left ventricular mass at the end of treatment. Co-administration of macitentan prevents sunitinib-induced hypertension, increase in ejection fraction and cardiac fibrosis, but fails to prevent increase of the left ventricular mass. Conclusion: Early metabolic changes predict sunitinib-induced cardiac remodeling. Endothelin blockade can prevent some but not all cardiotoxic side-effects of sunitinib, in particular left ventricle hypertrophy that appears to be induced by sunitinib through an endothelin-independent mechanism.

Keywords: cardiac hypertrophy; cardiotoxicity; endothelin; metabolic imaging.; sunitinib.

Figure 1

Study design: (A) A total of 23 tumor bearing nude mice were studied. 16 mice were imaged by PET and echography at baseline, week 1 and week 3, either under sunitinib (n = 8) or vehicle (n = 8) treatment and after 6 weeks of sunitinib treatment. Heart samples were collected at baseline (n = 4), week 3 (vehicle: n = 8; sunitinib: n = 3) and week 6 (n = 8). (B) non-tumor bearing mice (n = 28) were imaged by echography after 5 weeks of treatment with vehicle (n = 6) or sunitinib (n = 8) or macitentan (n = 7) or sunitinib+macitentan (n = 7). Hearts were collected at the last PET/echo scan. Echo: echocardiography; PET: Positron emission tomography; WB: western blot.

Figure 2

Sunitinib induces cardiac dysfunction: (A) Left ventricular fractional shortening measured at baseline, week 3 and week 6 for vehicle (open circles) and sunitinib-treated (filled circles) tumor bearing nude mice. (B) LV mass measured at baseline, week 3 and week 6 for vehicle (open circles) and sunitinib-treated (filled circles) tumor bearing nude mice. n = 8 per group. Data are expressed as mean ± SEM, ^** p < 0.01 compared to vehicle; ^$ p < 0.05, ^$$ p < 0.01 and ^$$$ p < 0.001 compared to baseline for sunitinib group. FS: Fractional shortening; LV: left ventricle.

Figure 3

Sunitinib induces cardiac remodeling: (A) Representative sections of myocardium stained for fibrosis (Picrosirius red) from hearts of non-treated mice (B) and mice treated with vehicle at week 3 (V-w3), or sunitinib at week 3 (S-w3) and week 6 (s-w6). Scale bar: 200 µm. (B) Quantification of fibrosis (normalized by tissue area) in tumor bearing nude mice non treated (blue, n = 4), treated with vehicle at week 3 (white, n = 8) or sunitinib at week 3 (striped, n = 3) and week 6 (black, n = 8). (C) Representative blots and their associated quantification for p-ERK and ERK (normalized by GAPDH) of tumor bearing nude mice treated with vehicle (open circles) or sunitinib (filled circles). Data expressed as mean ± SEM. ^$ p < 0.05 and ^$$ p < 0.01 compared to baseline for sunitinib group. ERK: Extracellular signal-regulated kinases.

Figure 4

Sunitinib enhances cardiac glycolytic metabolism at W1: (A) Example of PET scan images representing cardiac short axis view of FDG-SUV at baseline (left) and after one week (right) of sunitinib treatment. (B) Mean SUV measured at baseline, week 1, week 3 and week 6 for vehicle (open circles) and sunitinib-treated (filled circles) tumor bearing nude mice. (C) Max SUV measured at baseline, week 1, week 3 and week 6 for vehicle (open circles) and sunitinib-treated (filled circles) tumor bearing nude mice. (D) Pearson correlation between mean SUV at W1 and LV mass at W6 in sunitinib group. Each dot represents one mouse. Linear regression equation and coefficient of correlation (R) with R p-value are shown. n = 8 per group. Data are expressed as mean ± SEM, ^* p < 0.05 compared to vehicle; ^$ p < 0.05 compared to baseline for sunitinib group; LV: left ventricle; SUV: standard uptake values.

Figure 5

Macitentan prevents sunitinib-induced hypertension: Arterial pressure measured at baseline and after 3 weeks of vehicle (white, n = 6), sunitinib (black, n = 8), sunitinib+macitentan (dark grey, n = 7) and macitentan (grey, n = 7) treatment in non-tumor bearing mice. Data expressed in mean ± SEM. * p < 0.05 compared to other groups. SBP: systolic blood pressure. SBP: systolic blood pressure.

Figure 6

Macitentan prevents cardiac dysfunction: (A) Left ventricular ejection fraction measured after 5 weeks of vehicle (white), sunitinib (black), sunitinib+macitentan (dark grey) and macitentan (grey) treatment. (B) Interventricular septum/left ventricular posterior wall ratio measured after 5 weeks of vehicle (white), sunitinib (black), sunitinib+macitentan (dark grey) and macitentan (grey) treatment. (C) Left ventricular mass measured after 5 weeks of vehicle (white), sunitinib (black), sunitinib+macitentan (dark grey) and macitentan (grey) treatment. n = 6-8 per group. Data expressed in mean ± SEM. * p < 0.05 between two related samples. EF: ejection fraction; IVS: Interventricular septum; LVPW: Left ventricular posterior wall.

Figure 7

Macitentan prevents sunitinib-induced cardiac fibrosis: (A) Representative sections of myocardium stained for fibrosis (Picrosirius red) from hearts of mice treated with vehicle (upper left), sunitinib (upper right), sunitinib+macitentan (bottom left) and macitentan (bottom right). Scale bar: 200 µm. (B) Quantification of fibrosis (normalized by tissue area) in C57Bl/6, non-tumor bearing mice treated with vehicle (white, n = 6), sunitinib (black, n = 8), sunitinib+macitentan (dark grey, n = 7) and macitentan (grey, n = 7) treatment. (C) Representative blots and their associated quantification (D) for p-ERK and ERK (normalized by GAPDH) in C57Bl/6 mice treated with vehicle (white, n = 6), sunitinib (black, n = 6), sunitinib+macitentan (dark grey; n = 6) and macitentan (grey, n = 6). Data expressed in mean ± SEM. * p < 0.05; ** p < 0.01 between two related samples. ERK: Extracellular signal-regulated kinases.