The HER2 inhibitor lapatinib potentiates doxorubicin-induced cardiotoxicity through iNOS signaling

Advancements in understanding cardiotoxicity of EGFR- TKIs in non-small cell lung cancer treatment and beyond

Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors (EGFR-TKIs) are a class of oral targeted anticancer drugs that have been demonstrated to significantly inhibit tumor progression and improve clinical prognosis in patients diagnosed with EGFR-mutated tumors, particularly in those with non-small cell lung cancer. However, the sustained usage of EGFR-TKIs may cause potential cardiotoxicity, thus limiting their applicability. The primary objective of this review is to systematically analyze the evolving landscape of research pertaining to EGFR-TKI-induced cardiotoxicity and elucidate its underlying mechanisms, such as PI3K signaling pathway inhibition, ion channel blockade, oxidative stress, inflammatory responses, and apoptosis. Additionally, the review includes an exploration of risk assessment for cardiotoxicity induced by EGFR-TKIs, along with management and response strategies. Prospective research directions are outlined, emphasizing the need for more accurate predictors of cardiotoxicity and the development of innovative intervention strategies. In summation, this review consolidates recent research advances, illuminates the risks associated with EGFR-TKI-induced cardiac toxicity and presents crucial insights for refining clinical dosage protocols, optimizing patient management strategies, and unraveling the intricate mechanisms governing EGFR-TKI-induced cardiotoxicity.

Empagliflozin attenuates doxorubicin-induced cardiotoxicity by inhibiting the JNK signaling pathway

BACKGROUND

Sodium-glucose cotransporter-2 inhibitors, such as empagliflozin, are pivotal therapies for heart failure. However, the effect of empagliflozin on doxorubicin-related cardiac dysfunction remains unclear.

METHODS

Human induced pluripotent stem cell- and embryonic stem cell-derived cardiomyocytes were used to investigate the direct effect of empagliflozin on human cardiomyocytes. Then, the c-Jun amino-terminal kinases (JNK) inhibitor SP600125 was administered to the doxorubicin cardiotoxicity model in vitro and in vivo to investigate the role of JNK in empagliflozin.

RESULTS

In human stem cell-derived cardiomyocytes, pretreatment with empagliflozin attenuated doxorubicin-induced cleavage of caspase 3 and other apoptosis markers. Empagliflozin significantly attenuated doxorubicin-induced phosphorylation of JNK and p38. Inhibiting the phosphorylation of JNK (SP600125) or STAT3 attenuated doxorubicin-induced apoptosis, but inhibiting the phosphorylation of p38 did not. SP600125 inhibits the phosphorylation of STAT3 (S727), and a STAT3 (Y705) inhibitor also inhibits the phosphorylation of JNK. Empagliflozin and SP600125 attenuated doxorubicin-induced increases in reactive oxygen species (ROS) and decreases in oxidized nicotinamide adenine dinucleotide (NAD+). In animal studies, empagliflozin and SP600125 attenuated doxorubicin-induced cardiac dysfunction and fibrosis.

CONCLUSIONS

Empagliflozin attenuated doxorubicin-induced apoptosis by inhibiting the phosphorylation of JNK and its downstream signaling pathways, including ROS and NAD+.

Ferroptosis in Cancer Therapy: Mechanisms, Small Molecule Inducers, and Novel Approaches

Ferroptosis, a unique form of programmed cell death, is initiated by an excess of iron accumulation and lipid peroxidation-induced damage. There is a growing body of evidence indicating that ferroptosis plays a critical role in the advancement of tumors. The increased metabolic activity and higher iron levels in tumor cells make them particularly vulnerable to ferroptosis. As a result, the targeted induction of ferroptosis is becoming an increasingly promising approach for cancer treatment. This review offers an overview of the regulatory mechanisms of ferroptosis, delves into the mechanism of action of traditional small molecule ferroptosis inducers and their effects on various tumors. In addition, the latest progress in inducing ferroptosis using new means such as proteolysis-targeting chimeras (PROTACs), photodynamic therapy (PDT), sonodynamic therapy (SDT) and nanomaterials is summarized. Finally, this review discusses the challenges and opportunities in the development of ferroptosis-inducing agents, focusing on discovering new targets, improving selectivity, and reducing toxic and side effects.

Lapatinib combined with doxorubicin causes dose-dependent cardiotoxicity partially through activating the p38MAPK signaling pathway in zebrafish embryos

Because of its enhanced antitumor efficacy, lapatinib (LAP) is commonly used clinically in combination with the anthracycline drug doxorubicin (DOX) to treat metastatic breast cancer. While it is well recognized that this combination chemotherapy can lead to an increased risk of cardiotoxicity in adult women, its potential cardiotoxicity in the fetus during pregnancy remains understudied. Here, we aimed to examine the combination of LAP chemotherapy and DOX-induced cardiotoxicity in the fetus using a zebrafish embryonic system and investigate the underlying pathologic mechanisms. First, we examined the dose-dependent cardiotoxicity of combined LAP and DOX exposure in zebrafish embryos, which mostly manifested as pericardial edema, bradycardia, cardiac function decline and reduced survival. Second, we revealed that a significant increase in oxidative stress concurrent with activated MAPK signaling, as indicated by increased protein expression of phosphorylated p38 and Jnk, was a notable pathophysiological event after combined LAP and DOX exposure. Third, we showed that inhibiting MAPK signaling by pharmacological treatment with the p38MAPK inhibitor SB203580 or genetic ablation of the map2k6 gene could significantly alleviate combined LAP and DOX exposure-induced cardiotoxicity. Thus, we provided both pharmacologic and genetic evidence to suggest that inhibiting MAPK signaling could exert cardioprotective effects. These findings have implications for understanding the potential cardiotoxicity induced by LAP and DOX combinational chemotherapy in the fetus during pregnancy, which could be leveraged for the development of new therapeutic strategies.

Novel insights into cardiovascular toxicity of cancer targeted and immune therapies: Beyond ischemia with non-obstructive coronary arteries (INOCA)

Novel immune and targeted therapies approved over the past 2 decades have resulted in dramatic improvements in cancer-specific outcomes for many cancer patients. However, many of these agents can induce cardiovascular toxicity in a subset of patients. The field of cardio-oncology was established based on observations that anti-neoplastic chemotherapies and mantle radiation can lead to premature cardiomyopathy in cancer survivors. While conventional chemotherapy, targeted therapy, and immune therapies can all result in cardiovascular adverse events, the mechanisms, timing, and incidence of these events are inherently different. Many of these effects converge upon the coronary microvasculature to involve, through endocardial endothelial cells, a more direct effect through close proximity to cardiomyocyte with cellular communication and signaling pathways. In this review, we will provide an overview of emerging paradigms in the field of Cardio-Oncology, particularly the role of the coronary microvasculature in mediating cardiovascular toxicity of important cancer targeted and immune therapies. As the number of cancer patients treated with novel immune and targeted therapies grows exponentially and subsequently the number of long-term cancer survivors dramatically increases, it is critical that cardiologists and cardiology researchers recognize the unique potential cardiovascular toxicities of these agents.

Analysis and Validation of Critical Signatures and Immune Cell Infiltration Characteristics in Doxorubicin-Induced Cardiotoxicity by Integrating Bioinformatics and Machine Learning

Purpose

Doxorubicin-induced cardiotoxicity (DIC) is a severe side reaction in cancer chemotherapy that greatly impacts the well-being of cancer patients. Currently, there is still an insufficiency of effective and reliable biomarkers in the field of clinical practice for the early detection of DIC. This study aimed to determine and validate the potential diagnostic and predictive values of critical signatures in DIC.

Methods

We obtained high-throughput sequencing data from the GEO database and performed data analysis and visualization using R software, GO, KEGG and Cytoscape. Machine learning methods and weighted gene coexpression network (WGCNA) were used to identify key genes for diagnostic model construction. Receiver operating characteristic (ROC) analysis and a nomogram were used to assess their diagnostic values. A multiregulatory network was built to reveal the possible regulatory relationships of critical signatures. Cell-type identification by estimating relative subsets of RNA transcript (CIBERSORT) analysis was used to investigate differential immune cell infiltration. Additionally, a cell and animal model were constructed to investigate the relationship between the identified genes and DIC.

Results

Among the 3713 differentially expressed genes, three key genes (CSGALNACT1, ZNF296 and FANCB) were identified. A nomogram and ROC curves based on three key genes showed excellent diagnostic predictive performance. The regulatory network analysis showed that the TFs CREB1, EP300, FLI1, FOXA1, MAX, and MAZ modulated three key genes. An analysis of immune cell infiltration indicated that many immune cells (activated NK cells, M0 macrophages, activated dendritic cells and neutrophils) might be related to the progression of DIC. Furthermore, there may be various degrees of correlation between the three critical signatures and immune cells. RT‒qPCR demonstrated that the mRNA expression of CSGALNACT1 and ZNF296 was significantly upregulated, while FANCB was significantly downregulated in DOX-treated cardiomyocytes in vitro and in vivo.

Conclusion

Our study suggested that the differential expression of CSGALNACT1, ZNF296 and FANCB is associated with cardiotoxicity and is also involved in immune cell infiltration in DIC. They might be potential biomarkers for the early occurrence of DIC.

Trastuzumab potentiates doxorubicin-induced cardiotoxicity via activating the NLRP3 inflammasome in vivo and in vitro

Trastuzumab (Tra), the first humanized monoclonal antibody that targets human epidermal growth factor receptor 2 (HER2), is commonly used alongside doxorubicin (Dox) as a combination therapy in HER2-positive breast cancer. Unfortunately, this leads to a more severe cardiotoxicity than Dox alone. NLRP3 inflammasome is known to be involved in Dox-induced cardiotoxicity and multiple cardiovascular diseases. However, whether the NLRP3 inflammasome contributes to the synergistic cardiotoxicity of Tra has not been elucidated. In this study, primary neonatal rat cardiomyocyte (PNRC), H9c2 cells and mice were treated with Dox (15 mg/kg in mice or 1μM in cardiomyocyte) or Tra (15.75 mg/kg in mice or 1μM in cardiomyocyte), or Dox combined Tra as cardiotoxicity models to investigate this question. Our results demonstrated that Tra significantly potentiated Dox-induced cardiomyocyte apoptosis and cardiac dysfunction. These were accompanied by the increased expressions of NLRP3 inflammasome components (NLRP3, ASC and cleaved caspase-1), the secretion of IL-β and the pronounced production of ROS. Inhibiting the activation of NLRP3 inflammasome by NLRP3 silencing significantly reduced cell apoptosis and ROS production in Dox combined Tra-treated PNRC. Compared with the wild type mice, the systolic dysfunction, myocardial hypertrophy, cardiomyocyte apoptosis and oxidative stress induced by Dox combined Tra were alleviated in NLRP3 gene knockout mice. Our data revealed that the co-activation of NLRP3 inflammasome by Tra promoted the inflammation, oxidative stress and cardiomyocytes apoptosis in Dox combined Tra-induced cardiotoxicity model both in vivo and in vitro. Our results suggest that NLRP3 inhibition is a promising cardioprotective strategy in Dox/Tra combination therapy.

An integrative review of nonobvious puzzles of cellular and molecular cardiooncology

Oncologic patients are subjected to four major treatment types: surgery, radiotherapy, chemotherapy, and immunotherapy. All nonsurgical forms of cancer management are known to potentially violate the structural and functional integrity of the cardiovascular system. The prevalence and severity of cardiotoxicity and vascular abnormalities led to the emergence of a clinical subdiscipline, called cardiooncology. This relatively new, but rapidly expanding area of knowledge, primarily focuses on clinical observations linking the adverse effects of cancer therapy with deteriorated quality of life of cancer survivors and their increased morbidity and mortality. Cellular and molecular determinants of these relations are far less understood, mainly because of several unsolved paths and contradicting findings in the literature. In this article, we provide a comprehensive view of the cellular and molecular etiology of cardiooncology. We pay particular attention to various intracellular processes that arise in cardiomyocytes, vascular endothelial cells, and smooth muscle cells treated in experimentally-controlled conditions in vitro and in vivo with ionizing radiation and drugs representing diverse modes of anti-cancer activity.

Role of oxidative stress and inflammation-related signaling pathways in doxorubicin-induced cardiomyopathy

Doxorubicin (DOX) is a powerful and commonly used chemotherapeutic drug, used alone or in combination in a variety of cancers, while it has been found to cause serious cardiac side effects in clinical application. More and more researchers are trying to explore the molecular mechanisms of DOX-induced cardiomyopathy (DIC), in which oxidative stress and inflammation are considered to play a significant role. This review summarizes signaling pathways related to oxidative stress and inflammation in DIC and compounds that exert cardioprotective effects by acting on relevant signaling pathways, including the role of Nrf2/Keap1/ARE, Sirt1/p66Shc, Sirt1/PPAR/PGC-1α signaling pathways and NOS, NOX, Fe²⁺ signaling in oxidative stress, as well as the role of NLRP3/caspase-1/GSDMD, HMGB1/TLR4/MAPKs/NF-κB, mTOR/TFEB/NF-κB pathways in DOX-induced inflammation. Hence, we attempt to explain the mechanisms of DIC in terms of oxidative stress and inflammation, and to provide a theoretical basis or new idea for further drug research on reducing DIC. Video Abstract.

Pharmacogenomics in drug-induced cardiotoxicity: Current status and the future

Drug-induced cardiotoxicity (DICT) is an important concern of drug safety in both drug development and clinical application. The clinical manifestations of DICT include cardiomyopathy, arrhythmia, myocardial ischemia, heart failure, and a series of cardiac structural and functional changes. The occurrence of DICT has negative impacts on the life quality of the patients, brings additional social and economic burden. It is important to identify the potential factors and explore the mechanisms of DICT. Traditional cardiovascular risk factors can only partially explain the risk of DICT. Pharmacogenomic studies show accumulated evidence of genetics in DICT and suggest the potential to guide precision therapy to reduce risk of cardiotoxicity. The comprehensive application of technologies such as third-generation sequencing, human induced pluripotent stem (iPS) cells and genome editing has promoted the in-depth understanding of the functional role of susceptible genes in DICT. This paper reviewed drugs that cause DICT, the clinical manifestations and laboratory tests, as well as the related content of genetic variations associated with the risk of DICT, and further discussed the implication of new technologies in pharmacogenomics of DICT.

Involvement of kallikrein-PAR2-proinflammatory pathway in severe trastuzumab-induced cardiotoxicity

Trastuzumab‐induced cardiotoxicity interferes with continued treatment in approximately 10% of patients with ErbB2‐positive breast cancer, but its mechanism has not been fully elucidated. In this study, we recruited trastuzumab‐treated patients with ≥30% reduction in left ventricular ejection fraction (SP) and noncardiotoxic patients (NP). From each of these patients, we established three cases of induced pluripotent stem cell‐derived cardiomyocytes (pt‐iPSC‐CMs). Reduced contraction and relaxation velocities following trastuzumab treatment were more evident in SP pt‐iPSC‐CMs than NP pt‐iPSC‐CMs, indicating the cardiotoxicity phenotype could be replicated. Differences in ATP production, reactive oxygen species, and autophagy activity were observed between the two groups. Analysis of transcripts revealed enhanced kallikrein5 expression and pro‐inflammatory signaling pathways, such as interleukin‐1β, in SP pt‐iPSC‐CMs after trastuzumab treatment. The kallilkrein5‐protease‐activated receptor 2 (PAR2)‐MAPK signaling pathway was more activated in SP pt‐iPSC‐CMs, and treatment with a PAR2‐antagonist suppressed interleukin‐1β expression. Our data indicate enhanced pro‐inflammatory responses through kallikrein5‐PAR2 signaling and vulnerability to external stresses appear to be the cause of trastuzumab‐induced cardiotoxicity in SP.

In Vivo Murine Models of Cardiotoxicity Due to Anticancer Drugs: Challenges and Opportunities for Clinical Translation

Modern therapeutic approaches have led to an improvement in the chances of surviving a diagnosis of cancer. However, this may come with side effects, with patients experiencing adverse cardiovascular events or exacerbation of underlying cardiovascular disease related to their cancer treatment. Rodent models of chemotherapy-induced cardiotoxicity are useful to define pathophysiological mechanisms of cardiac damage and to identify potential therapeutic targets. The key mechanisms involved in cardiotoxicity induced by specific different antineoplastic agents are summarized in this state-of-the-art review, as well as the rodent models of cardiotoxicity by different classes of anticancer drugs, along with the strategies tested for primary and secondary cardioprotection. Current approaches for early detection of cardiotoxicity in preclinical studies with a focus on the application of advanced imaging modalities and biomarker strategies are also discussed. Potential applications of cardiotoxicity modelling in rodents are illustrated in relation to the advancements of promising research topics of cardiotoxicity. Created with BioRender.com.

Lapatinib induces mitochondrial dysfunction to enhance oxidative stress and ferroptosis in doxorubicin-induced cardiomyocytes via inhibition of PI3K/AKT signaling pathway

Lapatinib (LAP) is an important anti-cancer drug and is frequently alongside doxorubicin (DOX) as a combination therapy for better anti-cancer efficacy. However, many studies have reported that LAP in combination with DOX may induce highly cardiotoxicity. Accordingly, we aimed to explore the potential mechanism involved in the synergistic effect of LAP in DOX-induced cardiotoxicity. Here, cell counting kit-8 was used to detect cell viability and lactate dehydrogenase measurement was performed to assess cell injury. Cell apoptosis was evaluated by TUNEL assay and western blot assay. Mitochondrial dysfunction was identified by JC-1 assay, adenosine triphosphate (ATP) and Cytochrome C. Moreover, the activity of ROS, SOD, CAT and GSH were measured to elucidate oxidative stress level. Ferroptosis was examined by levels of Fe²⁺, GPX4 and ASCL4. Expressions of PI3K/AKT signaling were identified by western blot assay. The results revealed that LAP inhibited the cell viability and exacerbated cell injury induced by Dox, as well as increased cell apoptosis. LAP aggravated DOX-induced mitochondria damage by changed mitochondrial membrane potential, decreased ATP and increased level of Cytochrome C. In addition, the combination of LAP and DOX induced oxidative stress and ferroptosis in H9c2 cells. The activation of PI3K/AKT signaling reversed the detrimental effects of LAP on DOX-induced H9c2 cells. The data in this study showed for the first time that LAP aggravated Dox-induced cardiotoxicity by promoting oxidative stress and ferroptosis in cardiomyocytes via PI3K/AKT-mediated mitochondrial dysfunction, suggesting that PI3K/AKT activation is a promising cardioprotective strategy for DOX /LAX combination therapies.

Cardiotoxicity of Epidermal Growth Factor Receptor 2-Targeted Drugs for Breast Cancer

Breast cancer is the most common form of cancer in women and its incidence has been increasing over the years. Human epidermal growth factor receptor 2 (HER2 or ErbB2) overexpression is responsible for 20 to 25% of invasive breast cancers, and is associated with poor prognosis. HER2-targeted therapy has significantly improved overall survival rates in patients with HER2-positive breast cancer. However, despite the benefits of this therapy, its cardiotoxicity is a major concern, especially when HER2-targeted therapy is used in conjunction with anthracyclines. At present, the mechanism of this cardiotoxicity is not fully understood. It is thought that HER2-targeting drugs inhibit HER2/NRG 1 dimer formation, causing an increase in ROS in the mitochondria of cardiomyocytes and inhibiting the PI3K/Akt and Ras/MAPK pathways, resulting in cell apoptosis. Antioxidants, ACE inhibitors, angiotensin II receptor blockers, β-blockers, statins and other drugs may have a cardioprotective effect when used with ErbB2-targeting drugs. NT-proBNP can be used to monitor trastuzumab-induced cardiotoxicity during HER2-targeted treatment and may serve as a biological marker for clinical prediction of cardiotoxicity. Measuring NT-proBNP is non-invasive, inexpensive and reproducible, therefore is worthy of the attention of clinicians. The aim of this review is to discuss the potential mechanisms, clinical features, diagnostic strategies, and intervention strategies related to cardiotoxicity of ErbB2-targeting drugs.

Structural and Electrophysiological Changes in a Model of Cardiotoxicity Induced by Anthracycline Combined With Trastuzumab

Background

Combined treatment with anthracyclines (e.g., doxorubicin; Dox) and trastuzumab (Trz), a humanized anti-human epidermal growth factor receptor 2 (HER2; ErbB2) antibody, in patients with HER2-positive cancer is limited by cardiotoxicity, as manifested by contractile dysfunction and arrhythmia. The respective roles of the two agents in the cardiotoxicity of the combined therapy are incompletely understood.

Objective

To assess cardiac performance, T-tubule organization, electrophysiological changes and intracellular Ca²⁺ handling in cardiac myocytes (CMs) using an in vivo rat model of Dox/Trz-related cardiotoxicity.

Methods and Results

Adult rats received 6 doses of either Dox or Trz, or the two agents sequentially. Dox-mediated left ventricular (LV) dysfunction was aggravated by Trz administration. Dox treatment, but not Trz, induced T-tubule disarray. Moreover, Dox, but not Trz monotherapy, induced prolonged action potential duration (APD), increased incidence of delayed afterdepolarizations (DADs) and beat-to-beat variability of repolarization (BVR), and slower Ca²⁺ transient decay. Although APD, DADs, BVR and Ca²⁺ transient decay recovered over time after the cessation of Dox treatment, subsequent Trz administration exacerbated these abnormalities. Trz, but not Dox, reduced Ca²⁺ transient amplitude and SR Ca²⁺ content, although only Dox treatment was associated with SERCA downregulation. Finally, Dox treatment increased Ca²⁺ spark frequency, resting Ca²⁺ waves, sarcoplasmic reticulum (SR) Ca²⁺ leak, and long-lasting Ca²⁺ release events (so-called Ca²⁺ “embers”), partially reproduced by Trz treatment.

Conclusion

These results suggest that in vivo Dox but not Trz administration causes T-tubule disarray and pronounced changes in electrical activity of CMs. While adaptive changes may account for normal AP shape and reduced DADs late after Dox administration, subsequent Trz administration interferes with such adaptive changes. Intracellular Ca²⁺ handling was differently affected by Dox and Trz treatment, leading to SR instability in both cases. These findings illustrate the specific roles of Dox and Trz, and their interactions in cardiotoxicity and arrhythmogenicity.

Cardiotoxicity in HER2-positive breast cancer patients

Due to the recent advances in diagnosis and management of patients with HER2-positive breast cancer, especially through novel HER2-targeted agents, cardiotoxicity becomes an emerging problem. Although chemotherapy significantly increases survival, the risk of cardiovascular disease development is high and still underestimated and could imply treatment discontinuation. Frequently, due to lack of rigorous diagnosis strategies, cardiotoxicity assessment is delayed, and, moreover, the efficacy of current therapy options in restoring heart function is questionable. For a comprehensive risk assessment, it is vital to characterize the clinical spectrum of HER2-targeted agents and anthracyclines, as well as their pathogenic pathways involved in cardiotoxicity. Advanced cardiovascular multimodal imaging and circulating biomarkers plays primary roles in early assessing cardiotoxicity and also in guiding specific preventive measures. Even though the knowledge in this field is rapidly expanding, there are still questions that arise regarding the optimal approach in terms of timing and methods. The aim of the current review aims to providean overview of currently available data.

Use of hiPSC to explicate genomic predisposition to anthracycline-induced cardiotoxicity

The anticancer agents of the anthracycline family are commonly associated with the potential to cause severe toxicity to the heart. To solve the question of why particular a patient is predisposed to anthracycline-induced cardiotoxicity (AIC), researchers have conducted numerous pharmacogenomic studies and identified more than 60 loci associated with AIC. To date, none of these identified loci have been developed into US FDA-approved biomarkers for use in routine clinical practice. With advances in the application of human-induced pluripotent stem cell-derived cardiomyocytes, sequencing technologies and genomic editing techniques, variants associated with AIC can now be validated in a human model. Here, we provide a comprehensive overview of known genetic variants associated with AIC from the perspective of how human-induced pluripotent stem cell-derived cardiomyocytes can be used to help better explain the genomic predilection to AIC.

Cardiotoxicity of anthracycline-free targeted oncological therapies in HER2-positive breast cancer

Anthracycline drugs are considered to be pivotal drugs in numerous chemotherapy regimens for breast cancer. However, the cardiotoxicity associated with the treatment is an important issue to be addressed. With the emergence of increasingly diverse antitumor drugs, anthracycline-free therapies are able to reduce the cardiotoxicity caused by anthracycline drugs while ensuring that a therapeutic effect is achieved. In the present review, anthracycline-free oncological therapy regimens for the treatment of patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer and the associated cardiovascular toxicity are discussed, as well as some monitoring strategies. It is recommended that patients with HER2-positive breast cancer patients should receive adjuvant chemotherapy with single or dual-targeted therapy, with or without endocrine therapy according to the hormone receptor status determined by immunohistochemical examination. The main side effects of targeted therapy include cardiac dysfunction, hypertension and arrhythmia. According to individual risk stratification, it is recommended that patients should be periodically monitored using echocardiography, electrocardiography and serum markers, to enable the timely detection of the cardiovascular adverse reactions associated with tumor treatment, thereby preventing the morbidity and mortality caused by the cardiotoxicity of these drugs.

Intravenous administration of cardiac progenitor cell-derived exosomes protects against doxorubicin/trastuzumab-induced cardiac toxicity

AIMS

Combined administration of anthracyclines (e.g. doxorubicin; Dox) and trastuzumab (Trz), a humanized anti-human epidermal growth factor receptor 2 (HER2; ErbB2), is an effective treatment for HER2-positive breast cancer. However, both agents are associated with cardiac toxicity. Human cardiac-resident mesenchymal progenitor cells (CPCs) secrete extracellular vesicles including nanosized exosomes which protect against myocardial ischaemia. Here, we investigated the effects of these exosomes using a novel model of Dox/Trz-mediated cardiotoxicity.

METHODS AND RESULTS

CPCs were derived from cardiac atrial appendage specimens from patients who underwent heart surgery for heart valve disease and/or ischaemic heart disease, and exosomes were purified from CPC conditioned media. Proteomics analyses revealed that CPC exosomes contained multiple proteins involved in redox processes. Dox/Trz induced a significant increase in reactive oxygen species (ROS) in rat cardiomyocytes, which was prevented by CPC exosomes. In vivo, rats received six doses of Dox (Days 1-11), followed by six doses of Trz (Days 19-28). Three doses of either exosomes or exosome suspension vehicle were injected intravenously on Days 5, 11, and 19 in the treatment and control groups, respectively. Dox/Trz induced myocardial fibrosis, CD68+ inflammatory cell infiltrates, inducible nitric oxide synthase expression, and left ventricular dysfunction. CPC exosomes prevented these effects. These vesicles were highly enriched in miR-146a-5p compared with human dermal fibroblast exosomes. Dox upregulated Traf6 and Mpo, two known miR-146a-5p target genes (which encode signalling mediators of inflammatory and cell death axes) in myocytes. CPC exosomes suppressed miR-146a-5p target genes Traf6, Smad4, Irak1, Nox4, and Mpo in Dox-treated cells. Specific silencing of miR-146a-5p abrogated exosome-mediated suppression of those genes leading to an increase in Dox-induced cell death.

CONCLUSIONS

Human CPC exosomes attenuate Dox-/Trz-induced oxidative stress in cardiomyocytes. Systemic administration of these vesicles prevents Dox/Trz cardiotoxicity in vivo. miR-146a-5p mediates some of the benefits of exosomes in this setting.

Toll-like receptor 5 deficiency diminishes doxorubicin-induced acute cardiotoxicity in mice

Rationale: Clinical application of doxorubicin (DOX) is limited by its toxic cardiovascular side effects. Our previous study found that toll-like receptor (TLR) 5 deficiency attenuated cardiac fibrosis in mice. However, the role of TLR5 in DOX-induced cardiotoxicity remains unclear.

Methods: To further investigate this, TLR5-deficient mice were subjected to a single intraperitoneal injection of DOX to mimic an acute model.

Results: Here, we reported that TLR5 expression was markedly increased in response to DOX injection. Moreover, TLR5 deficiency exerted potent protective effects against DOX-related cardiac injury, whereas activation of TLR5 by flagellin exacerbated DOX injection-induced cardiotoxicity. Mechanistically, the effects of TLR5 were largely attributed to direct interaction with spleen tyrosine kinase to activate NADPH oxidase (NOX) 2, increasing the production of superoxide and subsequent activation of p38. The toxic effects of TLR5 activation in DOX-related acute cardiac injury were abolished by NOX2 deficiency in mice. Our further study showed that neutralizing antibody-mediated TLR5 depletion also attenuated DOX-induced acute cardiotoxicity.

Conclusion: These findings suggest that TLR5 deficiency attenuates DOX-induced cardiotoxicity in mice, and targeting TLR5 may provide feasible therapies for DOX-induced acute cardiotoxicity.

Screening for in-vivo regional contractile defaults to predict the delayed Doxorubicin Cardiotoxicity in Juvenile Rat

Anthracyclines are key chemotherapeutic agents used in various adult and pediatric cancers, however, their clinical use is limited due to possible congestive heart failure (HF) caused by acute and irreversible cardiotoxicity. Currently, there is no method to predict the future development of the HF in these patients. In order to identify early biomarkers to predict anthracycline cardiotoxicity in long-term survivors of childhood cancer, this longitudinal study aimed to analyze early and late in-vivo regional myocardial anthracycline-induced cardiotoxicity, related to in-vitro cardiac myocytes dysfunction, in a juvenile rat model. Methods: Young male Wistar rats (4 weeks-old) were treated with different cumulative doses of doxorubicin (7.5, 10 or 12.5 mg/kg) or NaCl (0.9%) once a week for 6 weeks by intravenous injection. Cardiac function was evaluated in-vivo by conventional (left ventricular ejection fraction, LVEF) and regional two-dimensional (2D) speckle tracking echocardiography over the 4 months after the last injection. The animals were assigned to preserved (pEF) or reduced EF (rEF) groups at the end of the protocol and were compared to controls. Results: We observed a preferential contractile dysfunction of the base of the heart, further altered in the posterior segment, even in pEF group. The first regional alterations appeared 1 month after chemotherapy. Functional investigation of cardiomyocytes isolated from the LV base 1 month after doxorubicin treatment showed that early in-vivo contractile alterations were associated with both decreased myofilament Ca²⁺ sensitivity and length-dependent activation. Changes in post-translational modifications (phosphorylation; S-glutathionylation) and protein degradation of the cardiac myosin binding protein-C may contribute to these alterations. Conclusion: Our data suggest that screening of the contractile defaults of the base of the heart by regional 2D strain echocardiography is useful to detect subclinical myocardial dysfunction prior to the development of delayed anthracycline-induced cardiomyopathy in pediatric onco-cardiology.

Human In Vitro Models for Assessing the Genomic Basis of Chemotherapy-Induced Cardiovascular Toxicity

Chemotherapy-induced cardiovascular toxicity (CICT) is a well-established risk for cancer survivors and causes diseases such as heart failure, arrhythmia, vascular dysfunction, and atherosclerosis. As our knowledge of the precise cardiovascular risks of each chemotherapy agent has improved, it has become clear that genomics is one of the most influential predictors of which patients will experience cardiovascular toxicity. Most recently, GWAS-led, top-down approaches have identified novel genetic variants and their related genes that are statistically related to CICT. Importantly, the advent of human-induced pluripotent stem cell (hiPSC) models provides a system to experimentally test the effect of these genomic findings in vitro, query the underlying mechanisms, and develop novel strategies to mitigate the cardiovascular toxicity liabilities due to these mechanisms. Here we review the cardiovascular toxicities of chemotherapy drugs, discuss how these can be modeled in vitro, and suggest how these models can be used to validate genetic variants that predispose patients to these effects.

Spliced X-box binding protein 1 induces liver cancer cell death via activating the Mst1-JNK-mROS signalling pathway

Previous studies have found that the primary pathogenesis of liver cancer progression is linked to excessive cancer cell proliferation and rapid metastasis. Although therapeutic advances have been made for the treatment of liver cancer, the mechanism underlying the liver cancer progression has not been fully addressed. In the present study, we explored the role of spliced X-box binding protein 1 (XBP1) in regulating the viability and death of liver cancer cells in vitro. Our study demonstrated that XBP1 was upregulated in liver cancer cells when compared to the primary hepatocytes. Interestingly, the deletion of XBP1 could reduce the viability of liver cancer cells in vitro via inducing apoptotic response. Further, we found that XBP1 downregulation was also linked to proliferation arrest and migration inhibition. At the molecular levels, XBP1 inhibition is followed by activation of the Mst1 pathway which promoted the phosphorylation of c-Jun N-terminal kinase (JNK). Then, the active Mst1-JNK pathway mediated mitochondrial reactive oxygen species (mROS) overproduction and then excessive ROS induced cancer cell death. Therefore, our study demonstrated a novel role played by XBP1 in modulating the viability of liver cancer cells via the Mst1-JNK-mROS pathways.

Mechanisms and potential interventions associated with the cardiotoxicity of ErbB2-targeted drugs: Insights from in vitro, in vivo, and clinical studies in breast cancer patients

Breast cancer is the most frequently occurring cancer among women worldwide. Human epidermal growth factor receptor 2 (HER2 or ErbB2) is overexpressed in between 20 and 25% of invasive breast cancers and is associated with poor prognosis. Trastuzumab, an anti-ErbB2 monoclonal antibody, reduces cancer recurrence and mortality in HER2-positive breast cancer patients, but unexpectedly induces cardiac dysfunction, especially when used in combination with anthracycline-based chemotherapy. Novel approved ErbB2-targeting drugs, including lapatinib, pertuzumab, and trastuzumab-emtansine, also potentially cause cardiotoxicity, although early clinical studies demonstrate their cardiac safety profile. Unfortunately, the mechanism involved in causing the cardiotoxicity is still not completely understood. In addition, the use of preventive interventions against trastuzumab-induced cardiac dysfunction, including angiotensin-converting enzyme inhibitors and beta-blockers, remain controversial. Thus, this review aims to summarize and discuss the evidence currently available from in vitro, in vivo, and clinical studies regarding the mechanism and potential interventions associated with the cardiotoxicity of ErbB2-targeted drugs.

Cerebral ischemia-reperfusion is modulated by macrophage-stimulating 1 through the MAPK-ERK signaling pathway

Cerebral ischemia-reperfusion (IR) injury is associated with mitochondrial damage. Macrophage-stimulating 1 (MST1) reportedly stimulates mitochondrial apoptosis by suppressing BCL-2. We investigated whether MST1 promotes the progression of cerebral IR injury by inducing mitochondrial dysfunction in vivo and in vitro. Western blot analysis, quantitative polymerase chain reaction, immunofluorescence, and mitochondrial function assays were conducted in cells from wild-type and Mst1-knockout mice subjected to cerebral IR injury. MST1 expression in wild-type glial cells increased following cerebral IR injury. Cerebral IR injury reduced the mitochondrial membrane potential and mitochondrial metabolism in glial cells, while it enhanced mitochondrial reactive oxygen species generation and mitochondrial calcium levels in these cells. The deletion of Mst1 attenuated cerebral IR injury by improving mitochondrial function and reducing mitochondrial damage. The mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway was suppressed in wild-type glial cell upon cerebral IR injury but was reactivated in Mst1-knockout glial cell. Accordingly, blocking the MAPK/ERK pathway abolished the beneficial effects of Mst1 deletion during cerebral IR injury by inducing mitochondrial damage in glial cells. Our results suggest that cerebral IR injury is associated with MST1 upregulation in the brain, while the genetic ablation of Mst1 can attenuate mitochondrial damage and sustain brain function following cerebral IR injury.

Pak2 inhibition promotes resveratrol-mediated glioblastoma A172 cell apoptosis via modulating the AMPK-YAP signaling pathway

As a polyphenolic compound, resveratrol (Res) is widely present in a variety of plants. Previous studies have shown that Res can inhibit various tumors. However, its role in c remains largely unexplored. In the present study, we first demonstrated that Res inhibited cell viability and induced apoptosis of glioblastoma A172 cell. Further experiments showed that Res induced mitochondrial dysfunction and activated the activity of caspase-9. Functional studies have found that Res treatment is associated with an increase in the expression of Pak2. Interestingly, inhibition of Pak2 could further augment the proapoptotic effect of Res. Mechanistically, Pak2 inhibition induced reactive oxygen species overproduction, mitochondria-JNK pathway activation, and AMPK-YAP axis suppression. However, overexpression of YAP could abolish the anticancer effects of Res and Pak2 inhibition, suggesting a necessary role played by the AMPK-YAP pathway in regulating cancer-suppressive actions of Res and Pak2 inhibition. Altogether, our results indicated that Res in combination with Pak2 inhibition could further enhance the anticancer property of Res and this effect is mediated via the AMPK-YAP pathway.

Inhibition of miR-25 attenuates doxorubicin-induced apoptosis, reactive oxygen species production and DNA damage by targeting PTEN

Background: Doxorubicin (DOX) is one of the widely used anti-cancer drugs, whereas it can induce irreversible cardiac injury in a dose-dependent manner which limits its utility in clinic. Our study aimed to investigate the relationship between miR-25 and DOX-induced cardiac injury and its underlying mechanism. Methods: Mice and H9c2 cells were exposed to DOX. The overexpressed or knockdown of miR-25 in H9c2 cells was achieved by miR-25 mimic or inhibitor and the efficiency of transfection was identified by qRT-PCR or Western blotting. Cell viability, apoptotic cell rate, and levels of apoptosis-related proteins were determined by CCK-8, flow cytometry, and Western blotting, respectively. Furthermore, Western blotting and immunofluorescence staining (IF) were performed to assess the expression levels of reactive oxygen species and degree of DNA damage. Results: As a result, DOX significantly upregulated miR-25 expression in mice and H9c2 cells and reduced cell viability and increased cell apoptosis in vitro and in vivo. miR-25 overexpression expedited cell injury induced by DOX in H9c2 cells demonstrated by the increased cell apoptosis and reactive oxygen species (ROS) production, whereas miR-25 inhibition attenuated the cell injury. Furthermore, miR-25 negatively controlled the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Intervention the expression of PTEN using si-PTEN reversed the beneficial effects of miR-25 inhibition on DOX-injured H9c2 cells. Conclusion: In conclusion, this study demonstrated that miR-25 is involved in DOX-induced cell damage through the regulation of PTEN expression.

Mononuclear phagocyte system blockade improves therapeutic exosome delivery to the myocardium

Rationale: Exosomes are emerging as a promising drug delivery carrier. However, rapid uptake of exosomes by the mononuclear phagocyte system (MPS) remains an obstacle for drug delivery into other targeted organs, including the heart. We hypothesized that prior blocking of uptake of exosomes by the MPS would improve their delivery to the targeted organs.

Methods: Exosomes were isolated from the cell culture medium. Fluorescence-labeled exosomes were tracked in vitro and in vivo by fluorescence imaging. The expression of clathrin heavy chain (Cltc), cavolin1, Pak1 and Rhoa, known genes for endocytosis, were profiled in various cell lines and organs by qPCR. The knockdown efficiency of siRNA against Cltc was analyzed by Western blotting. Exosome^control and exosome^blocking were constructed by encapsulating isolated exosomes with siControl or siClathrin via electroporation, while exosome^therapeutic was constructed by encapsulating isolated exosomes with miR-21a. Doxorubicin-induced cardiotoxicity model was used to verify the therapeutic efficiency of the exosome-based miR-21a delivery by echocardiography.

Results: Exosomes were preferentially accumulated in the liver and spleen, mainly due to the presence of abundant macrophages. Besides the well-known phagocytic effect, efficient endocytosis also contributes to the uptake of exosomes by macrophages. Cltc was found to be highly expressed in the macrophages compared with other endocytosis-associated genes. Accordingly, knockdown of Cltc significantly decreased the uptake of exosomes by macrophages in vitro and in vivo. Moreover, prior injection of exosome^blocking strikingly improved the delivery efficiency of exosomes to organs other than spleen and liver. Consistently, compared with the direct injection of exosome^therapeutic, prior injection of exosome^blocking produced a much better therapeutic effect on cardiac function in the doxorubicin-induced cardiotoxicity mouse model.

Conclusions: Prior blocking of endocytosis of exosomes by macrophages with exosome^blocking successfully and efficiently improves the distribution of following exosome^therapeutic in targeted organs, like the heart. The established two-step exosome delivery strategy (blocking the uptake of exosomes first followed by delivery of therapeutic exosomes) would be a promising method for gene therapy.

Yes-associated protein reduces neuroinflammation through upregulation of Sirt3 and inhibition of JNK signaling pathway

Objective: Neuroinflammation is linked to a series of neurodegenerative diseases through the unknown mechanisms.Aim: The aim of this study was to investigate the role of Yes-associated protein (Yap) in the regulation of neuroinflammation.Methods: BV-2 neuroglia cells were treated with TNFα in vitro. Then, western blots, qPCR, immunofluorescence, and ELISA were used to verify the influence of Yap in BV-2 cells neuroinflammation response.Results: After exposure to TNFα, viability of BV-2 cells decreased whereas apoptosis index was increased. Of note, Yap expression in BV-2 cells was significantly reduced, when compared to the normal cells. Interestingly, adenovirus-induced Yap overexpression was capable to reverse cell viability and thus reduce apoptotic index in TNFα-treated BV-2 cells. Molecular investigation demonstrated that Yap overexpression was linked to Sirt3 upregulation. Increased Sirt3 reduced endoplasmic reticulum (ER) stress, attenuated mitochondrial damage, and blocked JNK pro-apoptotic pathway. Interestingly, loss of Sirt3 abolished the protective effects induced by Yap overexpression in TNFα-treated BV-2 cells.Conclusions: Altogether, our results demonstrated that neuroinflammation could be caused by Yap downregulation, possible driven through Sirt3 inhibition and JNK activation. However, overexpression of Yap could protect BV-2 cells against TNFα-mediated apoptosis through modulating Sirt3-JNK signaling pathways.

LATS2 promotes cardiomyocyte H9C2 cells apoptosis via the Prx3-Mfn2-mitophagy pathways

Context: The pathogenesis of cardiomyocyte death is closely associated with mitochondrial homeostasis via poorly understood mechanisms.Objective: The aim of our study is to explore the contribution of large tumor suppressor kinase 2 (LATS2) to the apoptosis of cardiomyocyte H9C2 cells.Materials and Methods: Adenovirus-mediated LATS2 overexpression was carried out in H9C2 cells. The cell viability and apoptosis rate were measured via an MTT assay, TUNEL staining, western blotting, an ELISA, and an LDH release assay. Mitophagy was quantified using immunofluorescence and western blotting.Results: The overexpression of LATS2 in H9C2 cells drastically promoted cell death. Molecular investigations showed that LATS2 overexpression was associated with mitochondrial injury, as evidenced by increased mitochondrial ROS production, reduced antioxidant factor levels, increased cyt-c liberation into the nucleus and activated mitochondrial caspase-9-dependent apoptotic pathway activity. Furthermore, our results demonstrated that LATS2-mediated mitochondrial malfunction by repressing mitophagy and that the reactivation of mitophagy could sustain mitochondrial integrity and homeostasis in response to LATS2 overexpression. Furthermore, we found that LATS2 inhibited mitophagy by inactivating the Prx3-Mfn2 axis. The reactivation of Prx3-Mfn2 pathways abrogated the LATS2-mediated inhibition of mitochondrial apoptosis in H9C2 cells.Conclusions: The overexpression of LATS2 induces mitochondrial stress by repressing protective mitophagy in a manner dependent on Prx3-Mfn2 pathways, thus reducing the survival of H9C2 cells.

Sirt3 overexpression alleviates hyperglycemia-induced vascular inflammation through regulating redox balance, cell survival, and AMPK-mediated mitochondrial homeostasis

Context: Sirtuin-3 (Sirt3), a NAD-dependent deacetylase, has been reported to be involved in many biological processes.Objective: The present study aimed to investigate the effect and mechanism of Sirt3 on diabetic mice and human umbilical vein endothelial cells (HUVECs) under high glucose (HG) condition.Materials and methods: HUVECs were cultured under HG and inflammation pathway was determined via qPCR, western blots, and immunofluorescence.Results: Sirt3 expression was reduced in the progression of diabetic nephropathy. Overexpression of Sirt3 sustains renal function and retard the development of diabetic nephropathy. Mechanistically, Sirt3 overexpression attenuated hyperglycemia-mediated endothelial cells apoptosis in kidney. Besides, Sirt3 overexpression repressed oxidative injury and blocked caspase-9-related apoptosis pathway. Moreover, we found that Sirt3 overexpression was associated with AMPK activation and the latter elevates PGC1α-related mitochondrial protective system, especially mitochondrial autophagy. Loss of opa1 and/or inhibition of AMPK could depress mitochondrial autophagy and exacerbates mitochondrial function, finally contributing to the death of human renal mesangial cells.Conclusions: Our results demonstrated the beneficial effects of Sirt3 in the progression of diabetic nephropathy. Increased Sirt3-activated AMPK pathway, augments PGC1α-related mitochondrial protective system, sustained redox balance and closed caspase-9-involved apoptosis pathway in the setting of diabetic nephropathy.

Human iPSC banking: barriers and opportunities

The introduction of induced pluripotent stem cells (iPSCs) has opened up the potential for personalized cell therapies and ushered in new opportunities for regenerative medicine, disease modeling, iPSC-based drug discovery and toxicity assessment. Over the past 10 years, several initiatives have been established that aim to collect and generate a large amount of human iPSCs for scientific research purposes. In this review, we compare the construction and operation strategy of some iPSC banks as well as their ongoing development. We also introduce the technical challenges and offer future perspectives pertaining to the establishment and management of iPSC banks.

Major obstacles to doxorubicin therapy: Cardiotoxicity and drug resistance

Background

Doxorubicin is one of the most commonly prescribed and time-tested anticancer drugs. Although being considered as a first line drug in different types of cancers, the two main obstacles to doxorubicin therapy are drug-induced cardiotoxicity and drug resistance.

Method

The study utilizes systemic reviews on publications of previous studies obtained from scholarly journal databases including PubMed, Medline, Ebsco Host, Google Scholar, and Cochrane. The study utilizes secondary information obtained from health organizations using filters and keywords to sustain information relevancy. The study utilizes information retrieved from studies captured in the peer-reviewed journals on “doxorubicin-induced cardiotoxicity” and “doxorubicin resistance.”

Discussion and results

The exact mechanisms of cardiotoxicity are not known; various hypotheses are studied. Doxorubicin can lead to free radical generation in various ways. The commonly proposed underlying mechanisms promoting doxorubicin resistance are the expression of multidrug resistance proteins as well as other causes.

Conclusion

In this review, we have described the major obstacles to doxorubicin therapy, doxorubicin-induced cardiotoxicity as well as the mechanisms of cancer drug resistance and in following the treatment failures.

Lithocholic Acid, a Metabolite of the Microbiome, Increases Oxidative Stress in Breast Cancer

In breast cancer patients, the diversity of the microbiome decreases, coinciding with decreased production of cytostatic bacterial metabolites like lithocholic acid (LCA). We hypothesized that LCA can modulate oxidative stress to exert cytostatic effects in breast cancer cells. Treatment of breast cancer cells with LCA decreased nuclear factor-2 (NRF2) expression and increased Kelch-like ECH associating protein 1 (KEAP1) expression via activation of Takeda G-protein coupled receptor (TGR5) and constitutive androstane receptor (CAR). Altered NRF2 and KEAP1 expression subsequently led to decreased expression of glutathione peroxidase 3 (GPX3), an antioxidant enzyme, and increased expression of inducible nitric oxide synthase (iNOS). The imbalance between the pro- and antioxidant enzymes increased cytostatic effects via increased levels of lipid and protein oxidation. These effects were reversed by the pharmacological induction of NRF2 with RA839, tBHQ, or by thiol antioxidants. The expression of key components of the LCA-elicited cytostatic pathway (iNOS and 4HNE) gradually decreased as the breast cancer stage advanced. The level of lipid peroxidation in tumors negatively correlated with the mitotic index. The overexpression of iNOS, nNOS, CAR, KEAP1, NOX4, and TGR5 or the downregulation of NRF2 correlated with better survival in breast cancer patients, except for triple negative cases. Taken together, LCA, a metabolite of the gut microbiome, elicits oxidative stress that slows down the proliferation of breast cancer cells. The LCA-oxidative stress protective pathway is lost as breast cancer progresses, and the loss correlates with poor prognosis.

hiPSCs in cardio-oncology: deciphering the genomics

The genomic predisposition to oncology-drug-induced cardiovascular toxicity has been postulated for many decades. Only recently has it become possible to experimentally validate this hypothesis via the use of patient-specific human-induced pluripotent stem cells (hiPSCs) and suitably powered genome-wide association studies (GWAS). Identifying the individual single nucleotide polymorphisms (SNPs) responsible for the susceptibility to toxicity from a specific drug is a daunting task as this precludes the use of one of the most powerful tools in genomics: comparing phenotypes to close relatives, as these are highly unlikely to have been treated with the same drug. Great strides have been made through the use of candidate gene association studies (CGAS) and increasingly large GWAS studies, as well as in vivo whole-organism studies to further our mechanistic understanding of this toxicity. The hiPSC model is a powerful technology to build on this work and identify and validate causal variants in mechanistic pathways through directed genomic editing such as CRISPR. The causative variants identified through these studies can then be implemented clinically to identify those likely to experience cardiovascular toxicity and guide treatment options. Additionally, targets identified through hiPSC studies can inform future drug development. Through careful phenotypic characterization, identification of genomic variants that contribute to gene function and expression, and genomic editing to verify mechanistic pathways, hiPSC technology is a critical tool for drug discovery and the realization of precision medicine in cardio-oncology.

Primary cardiac manifestation of autosomal dominant polycystic kidney disease revealed by patient induced pluripotent stem cell-derived cardiomyocytes

Background

Mutations in PKD1 or PKD2 gene lead to autosomal dominant polycystic kidney disease (ADPKD). The mechanism of ADPKD progression and its link to increased cardiovascular mortality is still elusive.

Methods

We differentiated ADPKD patient induced pluripotent stem cells (iPSCs) to cardiomyocytes (CMs). The electrophysiological properties at the cellular level were analyzed by calcium imaging and whole cell patch clamping.

Findings

The ADPKD patient iPSC-CMs had decreased sarcoplasmic reticulum calcium content compared with Control-CMs. Spontaneous action potential of the PKD2 mutation line-derived CMs demonstrated slower beating rate and longer action potential duration. The PKD1 mutation line-derived CMs showed a comparable dose-dependent shortening of phase II repolarization with the Control-CMs, but a significant increase in beating frequency in response to L-type calcium channel blocker. The PKD1-mutant iPSC-CMs also showed a relatively unstable baseline as a greater percentage of cells exhibited delayed afterdepolarizations (DADs). Both the ADPKD patient iPSC-CMs showed more β-adrenergic agonist-elicited DADs compared with Control-CMs.

Interpretation

Characterization of ADPKD patient iPSC-CMs provides new insights into the increased clinical risk of arrhythmias, and the results enable disease modeling and drug screening for cardiac manifestations of ADPKD.

Fund

Ministry of Science and Technology, National Health Research Institutes, Academia Sinica Program for Technology Supporting Platform Axis Scheme, Thematic Research Program and Summit Research Program, and Kaohsiung Medical University Hospital, Taiwan.