Heme as a target for protection against doxorubicin-induced apoptosis in H9c2 cardiomyocytes

Doxorubicin-related cardiotoxicity: review of fundamental pathways of cardiovascular system injury

Over the years, advancements in the field of oncology have made remarkable strides in enhancing the efficacy of medical care for patients with cancer. These modernizations have resulted in prolonged survival and improved the quality of life for these patients. However, this progress has also been accompanied by escalation in mortality rates associated with anthracycline chemotherapy. Anthracyclines, which are known for their potent antitumor properties, are notorious for their substantial cardiotoxic potential. Remarkably, even after 6 decades of research, a conclusive solution to protect the cardiovascular system against doxorubicin-induced damage has not yet been established. A comprehensive understanding of the pathophysiological processes driving cardiotoxicity combined with targeted research is crucial for developing innovative cardioprotective strategies. This review seeks to explain the mechanisms responsible for structural and functional alterations in doxorubicin-induced cardiomyopathy.

The Bach1/HO-1 pathway regulates oxidative stress and contributes to ferroptosis in doxorubicin-induced cardiomyopathy in H9c2 cells and mice

Doxorubicin (DOX) is one of the most frequently used chemotherapeutic drugs belonging to the class of anthracyclines. However, the cardiotoxic effects of anthracyclines limit their clinical use. Recent studies have suggested that ferroptosis is the main underlying pathogenetic mechanism of DOX-induced cardiomyopathy (DIC). BTB-and-CNC homology 1 (Bach1) acts as a key role in the regulation of ferroptosis. However, the mechanistic role of Bach1 in DIC remains unclear. Therefore, this study aimed to investigate the underlying mechanistic role of Bach1 in DOX-induced cardiotoxicity using the DIC mice in vivo (DOX at cumulative dose of 20 mg/kg) and the DOX-treated H9c2 cardiomyocytes in vitro (1 μM). Our results show a marked upregulation in the expression of Bach1 in the cardiac tissues of the DOX-treated mice and the DOX-treated cardiomyocytes. However, Bach1-/- mice exhibited reduced lipid peroxidation and less severe cardiomyopathy after DOX treatment. Bach1 knockdown protected against DOX-induced ferroptosis in both in vivo and in vitro models. Ferrostatin-1 (Fer-1), a potent inhibitor of ferroptosis, significantly alleviated DOX-induced cardiac damage. However, the cardioprotective effects of Bach1 knockdown were reversed by pre-treatment with Zinc Protoporphyrin (ZnPP), a selective inhibitor of heme oxygenase-1(HO-1). Taken together, these findings demonstrated that Bach1 promoted oxidative stress and ferroptosis through suppressing the expression of HO-1. Therefore, Bach1 may present as a promising new therapeutic target for the prevention and early intervention of DOX-induced cardiotoxicity.

Upregulation of FAM129B protects cardiomyocytes from hypoxia/reoxygenation-induced injury by inhibiting apoptosis, oxidative stress, and inflammatory response via enhancing Nrf2/ARE activation

Family with sequence similarity 129, member B (FAM129B) has been identified as a novel cytoprotective protein that facilitates the survival of detrimentally stimulated cells. However, whether FAM129B is involved in regulating cardiomyocyte survival after myocardial ischemia-reperfusion injury is unknown. The goal of this work was to evaluate the potential role of FAM129B in regulating hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury in vitro. We demonstrated that exposure to H/R markedly downregulated the expression of FAM129B in cardiomyocytes. Functional experiments revealed that the upregulation of FAM129B improved H/R-exposed cardiomyocyte viability, and ameliorated H/R-induced cardiomyocyte apoptosis, the generation of reactive oxygen species (ROS), and pro-inflammatory cytokine release. The upregulation of FAM129B significantly increased the nuclear expression of nuclear factor-erythroid 2-related factor 2 (Nrf2), and reinforced Nrf2/antioxidant response element (ARE) activation in H/R-exposed cardiomyocytes. Moreover, FAM129B modulates Nrf2/ARE signaling in a Kelchlike ECH-associated protein 1-dependent manner. Notably, the inhibition of Nrf2 significantly blocked FAM129B-overexpression-induced cardioprotective effects in H/R-exposed cardiomyocytes. In summary, the findings of our work demonstrate that the upregulation of FAM129B ameliorates H/R-induced cardiomyocyte injury via enhancing Nrf2/ARE activation. Thus, our study indicates that FAM129B may play a role in myocardial ischemia-reperfusion injury and has the potential to be used as a cardioprotective target.

Ultrasonic-Assisted Enzymolysis Extraction and Protective Effect on Injured Cardiomyocytes in Mice of Flavonoids from Prunus mume Blossom

Prunus mume blossom is an edible flower that has been used in traditional Chinese medicine for thousands of years. Flavonoids are one of the most active substances in Prunus mume blossoms. The optimal ultrasonic-assisted enzymatic extraction of flavonoids from Prunus mume blossom (FPMB), the components of FPMB, and its protective effect on injured cardiomyocytes were investigated in this study. According to our results, the optimal extraction process for FPMB is as follows: cellulase at 2.0%, ultrasonic power at 300 W, ultrasonic enzymolysis for 30 min, and an enzymolysis temperature of 40 °C. FPMB significantly promoted the survival rate of cardiomyocytes and reduced the concentration of reactive oxygen species (ROS). FPMB also improved the activities of proteases caspase-3, caspase-8, and caspase-9 in cardiomyocytes. The cardiomyocyte apoptosis rate in mice was significantly reduced by exposure to FPMB. These results suggest that the extraction rate of FPMB may be improved by an ultrasonic-assisted enzymatic method. FPMB has a protective effect on the injured cardiomyocytes.

Protective Effects of Dexazoxane on Rat Ferroptosis in Doxorubicin-Induced Cardiomyopathy Through Regulating HMGB1

Dexrazoxane (DXZ) reduces cytotoxicity caused by Doxorubicin (DOX). However, the mechanism of DXZ in ferroptosis and cardiomyopathy remains unclear. This research, therefore, explores the role and mechanism of DXZ in DOX-induced ferroptosis and cardiomyopathy in rats. Kaplan–Meier survival analysis was performed in rats treated by DOX in combination with ferroptosis inhibitor (FER-1) or other cell death–associated inhibitors. The ferroptosis, cardiotoxicity, and expression of high mobility group box 1 (HMGB1) in rats treated by DOX in combination with FER-1 or with DXZ were determined by hematoxylin and eosin staining, echocardiographic analysis, and quantitative real-time PCR. The ferroptosis in DOX-treated rats that received HMGB1 knockdown or overexpression was further detected using molecular experiments. Finally, the viability, level of malondialdehyde (MDA), and expressions of ferroptosis-related markers (PTGS2, GPX4, and FTH1) of rat cardiomyocyte H9c2 exposed to DOX combined with FER-1, zVAD (an apoptosis inhibitor), DXZ, or not were detected by performing molecular experiments. FER-1 increased the survival of the rats induced by DOX. The DOX-induced ferroptosis and cardiotoxicity could be reversed by FER-1 or DXZ. HMGB1 was induced by DOX but was inhibited by DXZ or FER-1. Overexpression of HMGB1 promoted the ferroptosis and cardiotoxicity induced by DOX in the rats although silencing of HMGB1 showed opposite effects. The data indicate that DOX suppressed the viability and increased the MDA level in H9c2 cells in a dose-dependent manner. Moreover, DOX-induced increase of PTGS2 and decrease of GPX4 and FTH1 in H9c2 cells was reversed by DXZ or FER-1. Therefore, DXZ has protective effects on ferroptosis and cardiomyopathy in rats through regulating HMGB1.