Sunitinib and Imatinib Display Differential Cardiotoxicity in Adult Rat Cardiac Fibroblasts That Involves a Role for Calcium/Calmodulin Dependent Protein Kinase II

Sunitinib malate induces cell death in adult human cardiac progenitor cells

Sunitinib malate is known to cause cardiotoxicity in a sub-population of patients, with heart failure seen in more severe cases. Cardiac progenitor cells (CPCs) have been identified in adult human myocardium and contribute to overall tissue maintenance, with previous work identifying negative impacts of sunitinib on these cells. This study aimed to characterise the toxic effects of sunitinib in human CPCs, applying sunitinib concentrations equivalent to clinical plasma levels to these cells in vitro. Cell viability was reduced by 26.5 ± 6.6 % by 2 μM sunitinib for 24 h (p < 0.01); this concentration also induced fold-change increases in gene expression of: calpain (3.1 ± 0.73, p < 0.05), FAS (2.3 ± 0.8, p < 0.05) and BAX (1.9 ± 0.2, p < 0.05), and a decrease in BCL-2 (3.5 ± 0.0, p < 0.001), vs. control (1.0 ± 0.0). This was affirmed by sunitinib inducing fold changes in protein expression of: calpain-1 (2.5 ± 0.5, p < 0.05); FAS receptor (2.1 ± 0.2, p < 0.05) and BAX (2.1 ± 0.2, p < 0.05) vs. control (1.0 ± 0.0). These results indicated that sunitinib induced apoptosis in CPCs, but negative annexin V staining and lack of protection by caspase inhibitors indicated this was not the cell death pathway activated. Further investigation found sunitinib was concentrated in the lysosomes and autophagosomes within CPCs, but did not induce accumulation of acidic organelles. In conclusion, these data confirm that cell death is caused by sunitinib in CPCs at concentrations equivalent to clinical plasma levels, inducing cell death pathway signals that lead to non-apoptotic cell death.

The Role of p90 Ribosomal S6 Kinase (RSK) in Tyrosine Kinase Inhibitor (TKI)-Induced Cardiotoxicity

Targeted therapy, such as tyrosine kinase inhibitors (TKIs), has been approved to manage various cancer types. However, TKI-induced cardiotoxicity is a limiting factor for their use. This issue has raised the need for investigating potential cardioprotective techniques to be combined with TKIs. Ribosomal S6-kinases (RSKs) are a downstream effector of the mitogen-activated-protein-kinase (MAPK) pathway; specific RSK isoforms, such as RSK1 and RSK2, have been expressed in cancer cells, in which they increase tumour proliferation. Selective targeting of those isoforms would result in tumour suppression. Moreover, activation of RSKs expressed in the heart has resulted in cardiac hypertrophy and arrhythmia; thus, inhibiting RSKs would result in cardio-protection. This review article presents an overview of the usefulness of RSK inhibitors that can be novel agents to be assessed in future research for their effect in reducing cancer proliferation, as well as protecting the heart from cardiotoxicity induced by TKIs.

Exploring personalized treatment for cardiac graft rejection based on a four-archetype analysis model and bioinformatics analysis

Heart transplantation is the gold standard for treating patients with advanced heart failure. Although improvements in immunosuppressive therapies have significantly reduced the frequency of cardiac graft rejection, the incidences of T cell-mediated rejection (TCMR) and antibody-mediated rejection remain almost unchanged. A four-archetype analysis (4AA) model, developed by Philip F. Halloran, illustrated this problem well. It provided a new dimension to improve the accuracy of diagnoses and an independent system for recalibrating the histology guidelines. However, this model was based on the invasive method of endocardial biopsy, which undoubtedly increased the postoperative risk of heart transplant patients. Currently, little is known regarding the associated genes and specific functions of the different phenotypes. We performed bioinformatics analysis (using machine-learning methods and the WGCNA algorithm) to screen for hub-specific genes related to different phenotypes, based Gene Expression Omnibus accession number GSE124897. More immune cell infiltration was observed with the ABMR, TCMR, and injury phenotypes than with the stable phenotype. Hub-specific genes for each of the four archetypes were verified successfully using an external test set (accession number GSE2596). Logistic-regression models based on TCMR-specific hub genes and common hub genes were constructed with accurate diagnostic utility (area under the curve > 0.95). RELA, NFKB1, and SOX14 were identified as transcription factors important for TCMR/injury phenotypes and common genes, respectively. Additionally, 11 Food and Drug Administration-approved drugs were chosen from the DrugBank Database for each four-archetype model. Tyrosine kinase inhibitors may be a promising new option for transplant rejection treatment. KRAS signaling in cardiac transplant rejection is worth further investigation. Our results showed that heart transplant rejection subtypes can be accurately diagnosed by detecting expression of the corresponding specific genes, thereby enabling precise treatment or medication.

Role of RIPK3‑CaMKII‑mPTP signaling pathway‑mediated necroptosis in cardiovascular diseases (Review)

Necroptosis, which is distinct from apoptosis and necrosis, serves a crucial role in ontogeny and the maintenance of homeostasis. In the last decade, it has been demonstrated that the pathogenesis of cardiovascular diseases is also linked to necroptosis. Receptor interaction protein kinase (RIPK) 1, RIPK3 and mixed lineage kinase domain‑like protein serve vital roles in necroptosis. In addition to the aforementioned necroptosis‑related components, calcium/calmodulin‑dependent protein kinase II (CaMKII) has been identified as a novel substrate for RIPK3 that promotes the opening of the mitochondrial permeability transition pore (mPTP), and thus, mediates necroptosis of myocardial cells through the RIPK3‑CaMKII‑mPTP signaling pathway. The present review provides an overview of the current knowledge of the RIPK3‑CaMKII‑mPTP‑mediated necroptosis signaling pathway in cardiovascular diseases, focusing on the role of the RIPK3‑CaMKII‑mPTP signaling pathway in acute myocardial infarction, ischemia‑reperfusion injury, heart failure, abdominal aortic aneurysm, atherosclerosis, diabetic cardiomyopathy, hypertrophic cardiomyopathy, atrial fibrillation, and the cardiotoxicity associated with antitumor drugs and other chemicals. Finally, the present review discusses the research status of drugs targeting the RIPK3‑CaMKII‑mPTP signaling pathway.

Mitochondrial Dysfunction in Cardiotoxicity Induced by BCR-ABL1 Tyrosine Kinase Inhibitors -Underlying Mechanisms, Detection, Potential Therapies

The advent of BCR-ABL tyrosine kinase inhibitors (TKIs) targeted therapy revolutionized the treatment of chronic myeloid leukemia (CML) patients. Mitochondria are the key organelles for the maintenance of myocardial tissue homeostasis. However, cardiotoxicity associated with BCR-ABL1 TKIs can directly or indirectly cause mitochondrial damage and dysfunction, playing a pivotal role in cardiomyocytes homeostatic system and putting the cancer survivors at higher risk. In this review, we summarize the cardiotoxicity caused by BCR-ABL1 TKIs and the underlying mechanisms, which contribute dominantly to the damage of mitochondrial structure and dysfunction: endoplasmic reticulum (ER) stress, mitochondrial stress, damage of myocardial cell mitochondrial respiratory chain, increased production of mitochondrial reactive oxygen species (ROS), and other kinases and other potential mechanisms of cardiotoxicity induced by BCR-ABL1 TKIs. Furthermore, detection and management of BCR-ABL1 TKIs will promote our rational use, and cardioprotection strategies based on mitochondria will improve our understanding of the cardiotoxicity from a mitochondrial perspective. Ultimately, we hope shed light on clinical decision-making. By integrate and learn from both research and practice, we will endeavor to minimize the mitochondria-mediated cardiotoxicity and reduce the adverse sequelae associated with BCR-ABL1 TKIs.

Adverse effects of tyrosine kinase inhibitors in cancer therapy: pathophysiology, mechanisms and clinical management

Since their invention in the early 2000s, tyrosine kinase inhibitors (TKIs) have gained prominence as the most effective pathway-directed anti-cancer agents. TKIs have shown significant utility in the treatment of multiple hematological malignancies and solid tumors, including chronic myelogenous leukemia, non-small cell lung cancers, gastrointestinal stromal tumors, and HER2-positive breast cancers. Given their widespread applications, an increasing frequency of TKI-induced adverse effects has been reported. Although TKIs are known to affect multiple organs in the body including the lungs, liver, gastrointestinal tract, kidneys, thyroid, blood, and skin, cardiac involvement accounts for some of the most serious complications. The most frequently reported cardiovascular side effects range from hypertension, atrial fibrillation, reduced cardiac function, and heart failure to sudden death. The potential mechanisms of these side effects are unclear, leading to critical knowledge gaps in the development of effective therapy and treatment guidelines. There are limited data to infer the best clinical approaches for the early detection and therapeutic modulation of TKI-induced side effects, and universal consensus regarding various management guidelines is yet to be reached. In this state-of-the-art review, we examine multiple pre-clinical and clinical studies and curate evidence on the pathophysiology, mechanisms, and clinical management of these adverse reactions. We expect that this review will provide researchers and allied healthcare providers with the most up-to-date information on the pathophysiology, natural history, risk stratification, and management of emerging TKI-induced side effects in cancer patients.

Imatinib attenuates reperfusion injury in a rat model of acute myocardial infarction

Following an acute myocardial infarction, reperfusion of an occluded coronary artery is often accompanied by microvascular injury, leading to worse long-term prognosis. Experimental studies have revealed the potential of tyrosine-kinase inhibitor imatinib to reduce vascular leakage in various organs. Here, we examined the potential of imatinib to attenuate microvascular injury in a rat model of myocardial reperfusion injury. Isolated male Wistar rat hearts (n = 20) in a Langendorff system and male Wistar rats (n = 37) in an in vivo model were randomly assigned to imatinib or placebo and subjected to ischaemia and reperfusion. Evans-blue/Thioflavin-S/TTC staining and Cardiac Magnetic Resonance Imaging were performed to assess the extent of reperfusion injury. Subsequently, in vivo hearts were perfused ex vivo with a vascular leakage tracer and fluorescence and electron microscopy were performed. In isolated rat hearts, imatinib reduced global infarct size, improved end-diastolic pressure, and improved rate pressure product recovery compared to placebo. In vivo, imatinib reduced no-reflow and infarct size with no difference between imatinib and placebo for global cardiac function. In addition, imatinib showed lower vascular resistance, higher coronary flow, and less microvascular leakage in the affected myocardium. At the ultrastructural level, imatinib showed higher preserved microvascular integrity compared to placebo. We provide evidence that low-dose imatinib can reduce microvascular injury and accompanying myocardial infarct size in a rat model of acute myocardial infarction. These data warrant future work to examine the potential of imatinib to reduce reperfusion injury in patients with acute myocardial infarction.

Intracellular Signaling Pathways Mediating Tyrosine Kinase Inhibitor Cardiotoxicity

Tyrosine kinase inhibitors (TKIs) are used to treat several cancers; however, a myriad of adverse cardiotoxic effects remain a primary concern. Although hypertension (HTN) is the most common adverse effect reported with TKI therapy, incidents of arrhythmias (eg, QT prolongation, atrial fibrillation) and heart failure are also prevalent. These complications warrant further research toward understanding the mechanisms of TKI-induced cardiotoxicity. Recent literature has given some insight into the intracellular signaling pathways that may mediate TKI-induced cardiac dysfunction. In this article, we discuss the cardiotoxic effects of TKIs on cardiomyocyte function, signaling, and possible treatments.

Cardiotoxicity of Anticancer Drugs: Molecular Mechanisms and Strategies for Cardioprotection

Chemotherapy and targeted therapies have significantly improved the prognosis of oncology patients. However, these antineoplastic treatments may also induce adverse cardiovascular effects, which may lead to acute or delayed onset of cardiac dysfunction. These common cardiovascular complications, commonly referred to as cardiotoxicity, not only may require the modification, suspension, or withdrawal of life-saving antineoplastic therapies, with the risk of reducing their efficacy, but can also strongly impact the quality of life and overall survival, regardless of the oncological prognosis. The onset of cardiotoxicity may depend on the class, dose, route, and duration of administration of anticancer drugs, as well as on individual risk factors. Importantly, the cardiotoxic side effects may be reversible, if cardiac function is restored upon discontinuation of the therapy, or irreversible, characterized by injury and loss of cardiac muscle cells. Subclinical myocardial dysfunction induced by anticancer therapies may also subsequently evolve in symptomatic congestive heart failure. Hence, there is an urgent need for cardioprotective therapies to reduce the clinical and subclinical cardiotoxicity onset and progression and to limit the acute or chronic manifestation of cardiac damages. In this review, we summarize the knowledge regarding the cellular and molecular mechanisms contributing to the onset of cardiotoxicity associated with common classes of chemotherapy and targeted therapy drugs. Furthermore, we describe and discuss current and potential strategies to cope with the cardiotoxic side effects as well as cardioprotective preventive approaches that may be useful to flank anticancer therapies.

Alteration of N6-Methyladenosine mRNA Methylation in a Human Stem Cell-Derived Cardiomyocyte Model of Tyrosine Kinase Inhibitor-Induced Cardiotoxicity

Background

N⁶-methyladenosine (m⁶A) plays important roles in various cardiovascular diseases (CVDs), including cardiac hypertrophy and heart failure. Sunitinib (SUN) is a tyrosine kinase inhibitor (TKI) that is widely used in the treatment of different types of solid and blood tumors, but its efficacy is restricted by a concomitant rise in cardiotoxicities. However, the methylation modification of m⁶A messenger RNA (mRNA) in cardiomyocytes treated with TKI has not been investigated.

Methods

The global m⁶A methylation level of SUN-induced cardiotoxicity was detected by m⁶A dot blot and colorimetric methylation assay. MeRIP-Seq (methylated RNA immunoprecipitation sequencing) and RNA-seq (RNA sequencing, input) were employed to depict the landscapes of transcriptome and epitranscriptome in TKI. Changes in major m⁶A-related enzymes were detected by qRT-PCR and Western blot. In addition, the effects of FTO on SUN-induced cardiotoxicity were evaluated by gain and loss of function studies.

Results

In this study, we observed that the m⁶A methylation level was significantly elevated in SUN-treated human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and paralleled a positively correlated cellular damage level. Through a genome-wide analysis of m⁶A mRNA methylation by methylated RNA immunoprecipitation sequencing (MeRIP-seq) and input RNA sequencing (RNA-seq), we identified a total of 2,614 peaks with significant changes, of which 1,695 peaks were significantly upregulated and 919 peaks were significantly downregulated. Quantitative reverse transcription PCR (RT-qPCR), immunofluorescence, and Western blotting revealed that the RNA demethylase fat mass and obesity-associated protein (FTO) was downregulated, whereas the RNA methylases methyltransferase-like 14 (METTL14) and wilms' tumor 1-associating protein (WTAP) were upregulated. Furthermore, gain- and loss-of-function studies substantiated that FTO is cardioprotective in TKI.

Conclusion

This study deciphered the methylation modification of m⁶A mRNA in hiPSC-CMs post-TKI treatment and determined that FTO may be a promising therapeutic target for TKI-induced cardiotoxicity.

Impact of Selected Small-Molecule Kinase Inhibitors on Lipid Membranes

Small-molecule protein kinase inhibitors are used for the treatment of various diseases. Although their effect(s) on the respective kinase are generally quite well understood, surprisingly, their interaction with membranes is only barely investigated; even though these drugs necessarily come into contact with the plasma and intracellular membranes. Using biophysical methods such as NMR, ESR, and fluorescence spectroscopy in combination with lipid vesicles, we studied the membrane interaction of the kinase inhibitors sunitinib, erlotinib, idelalisib, and lenvatinib; these drugs are characterized by medium log p values, a parameter reflecting the overall hydrophobicity of the molecules, which is one important parameter to predict the interaction with lipid membranes. While all four molecules tend to embed in a similar region of the lipid membrane, their presence has different impacts on membrane structure and dynamics. Most notably, sunitinib, exhibiting the lowest log p value of the four inhibitors, effectively influences membrane integrity, while the others do not. This shows that the estimation of the effect of drug molecules on lipid membranes can be rather complex. In this context, experimental studies on lipid membranes are necessary to (i) identify drugs that may disturb membranes and (ii) characterize drug-membrane interactions on a molecular level. Such knowledge is important for understanding the efficacy and potential side effects of respective drugs.