Role of metabolites of cyclophosphamide in cardiotoxicity

Abstract

Background: The dose-limiting toxic effect of cyclophosphamide (CY) is cardiotoxicity. The pathogenesis of myocardial damage is poorly understood, and there is no established means of prevention. In previous studies, we suggested that for CY-induced cardiotoxicity, whereas acrolein is the key toxic metabolite, carboxyethylphosphoramide mustard (CEPM) is protective. We sought to verify that acrolein is the main cause of cardiotoxicity and to investigate whether aldehyde dehydrogenase (ALDH), which is associated with greater CEPM production, is involved in the protective effect for cardiotoxicity. We also evaluated the protective effect of N-acetylcysteine (NAC), an amino acid with antioxidant activity and a known acrolein scavenger.Methods: H9c2 cells were exposed to CY metabolites HCY (4-hydroxy-cyclophosphamide), acrolein or CEPM. The degree of cytotoxicity was evaluated by MTT assay, lactate dehydrogenase (LDH) release, and the production of reactive oxygen species (ROS). We also investigated how the myocardial cellular protective effects of CY metabolites were modified by NAC. To quantify acrolein levels, we measured the culture supernatants using high performance liquid chromatography. We measured ALDH activity after exposure to HCY or acrolein and the same with pre-treatment with NAC.Results: Exposure of H9c2 cells to CEPM did not cause cytotoxicity. Increased ROS levels and myocardial cytotoxicity, however, were induced by HCY and acrolein. In cell cultures, HCY was metabolized to acrolein. Less ALDH activity was observed after exposure to HCY or acrolein. Treatment with NAC reduced acrolein concentrations. Conclusions:Increased ROS generation and decreased ALDH activity confirmed that CY metabolites HCY and acrolein are strongly implicated in cardiotoxicity. By inhibiting ROS generation, increasing ALDH activity and decreasing the presence of acrolein, NAC has the potential to prevent CY-induced cardiotoxicity.

Molecular Mechanisms of Cardiomyocyte Death in Drug-Induced Cardiotoxicity

“…Because of the dosedependent manner, cyclophosphamide-induced cardiotoxicity basically coincides with high-dose treatment (Nishikawa et al, 2015;Wadia, 2015). Acrolein, the active metabolite of cyclophosphamide, was confirmed to be mainly responsible for cardiomyocyte death (Conklin et al, 2015;Nishikawa et al, 2015;Kurauchi et al, 2017). The cardiomyocyte injuries caused by cyclophosphamide treatment included sarcoplasmic reticulum dilatation, mitochondrial disruption and nuclear membrane invagination (Lushnikova et al, 2008).…”

“…The cardiomyocyte injuries caused by cyclophosphamide treatment included sarcoplasmic reticulum dilatation, mitochondrial disruption and nuclear membrane invagination (Lushnikova et al, 2008). Further studies attributed these injuries to oxidative stress, clarifying that acrolein caused oxidative and nitrite stress through the suppression of intracellular GSH and SOD and increase of MDA (Nagi et al, 2011;Kurauchi et al, 2017;Omole et al, 2018). Corresponding lipid peroxidation initiated mitochondrial function damage, which further led to a collapse in APT production and the activation of caspase-3, resulting in apoptosis (Nagi et al, 2011;Refaie et al, 2020).…”

CYP1B1 as a therapeutic target in cardio-oncology

“…Cyclophosphamide is another alkylating chemotherapeutic agent used to treat a variety of cancers. At high doses, cyclophosphamide has been reported to cause cardiotoxic effects [361] that are usually manifested in the forms of myocyte damage, edema, and hemorrhagic necrotic perimyocarditis [362,363]. In contrast with other chemotherapeutic agents, cyclophosphamide has been shown to inhibit CYP1B1 gene expression in HL-6 human acute promyelocytic leukemia cell line [175].…”

Rapid changes in chromatin structure during dedifferentiation of primary hepatocytes in vitro

“…Occasionally approved drugs can cause hepatotoxicity, with more than 40,000 yearly cases of drug-induced liver injury reported in the United States alone [2]. In addition, hepatocytes can convert nontoxic compounds into compounds that are toxic to other organs, as is seen with nephrotoxicity of haloalkenes [3] and cardiotoxicity of the prodrug cyclophosphamide [4]. Animal testing is currently required before proceeding to phase I clinical trials, but the concordance to human toxicity can be poor [5,6].…”