Mechanisms of cardiotoxicity associated with ErbB2 inhibitors

ErbB2-NOTCH1 axis controls autophagy in cardiac cells

Although the epidermal growth factor receptor 2 (ErbB2) and Notch1 signaling pathways have both significant roles in regulating cardiac biology, their interplay in the heart remains poorly investigated. Here, we present evidence of a crosstalk between ErbB2 and Notch1 in cardiac cells, with effects on autophagy and proliferation. Overexpression of ErbB2 in H9c2 cardiomyoblasts induced Notch1 activation in a post-transcriptional, p38-dependent manner, while ErbB2 inhibition with the specific inhibitor, lapatinib, reduced Notch1 activation. Moreover, incubation of H9c2 cells with lapatinib resulted in stalled autophagic flux and decreased proliferation, consistent with the established cardiotoxicity of this and other ErbB2-targeting drugs. Confirming the findings in H9c2 cells, exposure of primary neonatal mouse cardiomyocytes to exogenous neuregulin-1, which engages ErbB2, stimulated proliferation, and this effect was abrogated by concomitant inhibition of the enzyme responsible for Notch1 activation. Furthermore, the hearts of transgenic mice specifically overexpressing ErbB2 in cardiomyocytes had increased levels of active Notch1 and of Notch-related genes. These data expand the knowledge of ErbB2 and Notch1 functions in the heart and may allow better understanding the mechanisms of the cardiotoxicity of ErbB2-targeting cancer treatments.

Mechanisms of Cardiovascular Toxicities Induced by Cancer Therapies and Promising Biomarkers for Their Prediction: A Scoping Review

AIM

With the advancement of anti-cancer medicine, cardiovascular toxicities due to cancer therapies are common in oncology patients, resulting in increased mortality and economic burden. Cardiovascular toxicities caused by cancer therapies include different severities of cardiomyopathy, arrhythmia, myocardial ischaemia, hypertension, and thrombosis, which may lead to left ventricular dysfunction and heart failure. This scoping review aimed to summarise the mechanisms of cardiovascular toxicities following various anti-cancer treatments and potential predictive biomarkers for early detection.

METHODS

PubMed, Cochrane, Embase, Web of Science, Scopus, and CINAHL databases were searched for original studies written in English related to the mechanisms of cardiovascular toxicity induced by anti-cancer therapies, including chemotherapy, targeted therapy, immunotherapy, radiation therapy, and relevant biomarkers. The search and title/abstract screening were conducted independently by two reviewers, and the final analysed full texts achieved the consensus of the two reviewers.

RESULTS

A total of 240 studies were identified based on their titles and abstracts. In total, 107 full-text articles were included in the analysis. Cardiomyocyte and endothelial cell apoptosis caused by oxidative stress injury, activation of cell apoptosis, blocking of normal cardiovascular protection signalling pathways, overactivation of immune cells, and myocardial remodelling were the main mechanisms. Promising biomarkers for anti-cancer therapies related to cardiovascular toxicity included placental growth factor, microRNAs, galectin-3, and myeloperoxidase for the early detection of cardiovascular toxicity.

CONCLUSION

Understanding the mechanisms of cardiovascular toxicity following various anti-cancer treatments could provide implications for future personalised treatment methods to protect cardiovascular function. Furthermore, specific early sensitive and stable biomarkers of cardiovascular system damage need to be identified to predict reversible damage to the cardiovascular system and improve the effects of anti-cancer agents.

Cardiotoxicity of breast cancer chemotherapy

Breast cancer is one of the leading causes of malignancy affecting women in the United States. Although many effective treatments are available, most come with notable side effects that providers and patients must take into consideration. Various classes of chemotherapeutic agents, including anthracyclines and human epidermal growth factor receptor-2 antagonists, are known to be toxic to myocardial tissue. In this review article, we discuss what is reported in the literature regarding the cardiotoxicity of these agents as well as how to monitor and prevent cardiac injury and dysfunction.

Mechanisms of trastuzumab induced cardiotoxicity - is exercise a potential treatment?

The use of the adjuvant therapeutic antibody trastuzumab in breast cancer is associated with a range of cardiotoxic side effects despite successfully reducing the severity of outcomes cancer patients,. The most common cardiac effect, a reduction in left ventricular ejection fraction (LVEF), is a known precursor to heart failure and often requires interruption of chemotherapy to avoid endangering patients further. An understanding of trastuzumab's cardiac-specific interactions is therefore critical in devising new methods to not only avoid permanent cardiac damage, but also prolong treatment time, and therefore effectiveness, for breast cancer patients. Increasingly, the use of exercise as a treatment has been indicated across the field of cardio-oncology due to encouraging evidence that it can protect against LVEF reductions and heart failure. This review explores the mechanisms of trastuzumab-mediated cardiotoxicity, as well as the physiological effects of exercise on the heart, in order to assess the suitability of exercise intervention for breast cancer patients on trastuzumab antibody-therapy. We furthermore draw comparison to existing evidence for exercise intervention as a cardioprotective treatment in doxorubicin-induced cardiotoxicity. Although preclinical evidence seems to support exercise-based approaches also in trastuzumab-cardiotoxicity, current clinical evidence is too limited to confidently recommend it as a treatment, largely owing to issues of adherence. Future studies should therefore examine how the variety and duration of exercise can be adjusted to improve treatment effectiveness at a more personalised level.

Protocol for pyrotinib cardiac safety in patients with HER2-positive early or locally advanced breast cancer-The EARLY-MYO-BC study

Background and aim

Cardiotoxicity has become the most common cause of non-cancer death among breast cancer patients. Pyrotinib, a tyrosine kinase inhibitor targeting HER2, has been successfully used to treat breast cancer patients but has also resulted in less well-understood cardiotoxicity. This prospective, controlled, open-label, observational trial was designed to characterize pyrotinib's cardiac impacts in the neoadjuvant setting for patients with HER2-positive early or locally advanced breast cancer.

Patients and methods

The EARLY-MYO-BC study will prospectively enroll HER2-positive breast cancer patients who are scheduled to receive four cycles of neoadjuvant therapy with pyrotinib or pertuzumab added to trastuzumab before radical breast cancer surgery. Patients will undergo comprehensive cardiac assessment before and after neoadjuvant therapy, including laboratory measures, electrocardiography, transthoracic echocardiography, cardiopulmonary exercise testing (CPET), and cardiac magnetic resonance (CMR). To test the non-inferiority of pyrotinib plus trastuzumab therapy to pertuzumab plus trastuzumab therapy in terms of cardiac safety, the primary endpoint will be assessed by the relative change in global longitudinal strain from baseline to completion of neoadjuvant therapy by echocardiography. The secondary endpoints include myocardial diffuse fibrosis (by T1-derived extracellular volume), myocardial edema (by T2 mapping), cardiac volumetric assessment by CMR, diastolic function (by left ventricular volume, left atrial volume, E/A, and E/E') by echocardiography, and exercise capacity by CPET.

Discussion

This study will comprehensively assess the impacts of pyrotinib on myocardial structural, function, and tissue characteristics, and, furthermore, will determine whether pyrotinib plus trastuzumab is a reasonable dual HER2 blockade regimen with regard to cardiac safety. Results may provide information in selecting an appropriate anti-HER2 treatment for HER2-positive breast cancer.

Clinical trial registration

https://clinicaltrials.gov/, identifier NCT04510532.

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.

Cardio-Oncology Rehabilitation-Present and Future Perspectives

Recent advances in cancer therapy have led to increased survival rates for cancer patients, but also allowed cardiovascular complications to become increasingly evident, with more than 40% of cancer deaths now being attributed to cardiovascular diseases. Cardiotoxicity is the most concerning cardiovascular complication, one caused mainly due to anti-cancer drugs. Among the harmful mechanisms of these drugs are DNA damage, endothelial dysfunction, and oxidative stress. Cancer patients can suffer reduced cardiorespiratory fitness as a secondary effect of anti-cancer therapies, tumor burden, and deconditioning. In the general population, regular exercise can reduce the risk of cardiovascular morbidity, mortality, and cancer. Exercise-induced modifications of gene expression result in improvements of cardiovascular parameters and an increased general fitness, influencing telomere shortening, oxidative stress, vascular function, and DNA repair mechanisms. In cancer patients, exercise training is generally safe and well-tolerated; it is associated with a 10-15% improvement in cardiorespiratory fitness and can potentially counteract the adverse effects of anti-cancer therapy. It is well known that exercise programs can benefit patients with heart disease and cancer, but little research has been conducted with cardio-oncology patients. To date, there are a limited number of effective protective treatments for preventing or reversing cardiotoxicity caused by cancer therapy. Cardiac rehabilitation has the potential to mitigate cardiotoxicity based on the benefits already proven in populations suffering from either cancer or heart diseases. Additionally, the fact that cardiotoxic harm mechanisms coincide with similar mechanisms positively affected by cardiac rehabilitation makes cardiac rehabilitation an even more plausible option for cardio-oncology patients. Due to unstable functional capacity and fluctuating immunocompetence, these patients require specially tailored exercise programs designed collaboratively by cardiologists and oncologists. As the digital era is here, with the digital world and the medical world continuously intertwining, a remote, home-based cardio-oncology rehabilitation program may be a solution for this population.

Adoptive T-Cell Therapy in Advanced Colorectal Cancer: A Systematic Review

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the US. For the vast majority of patients with advanced CRC (ie, for those in whom metastatic tumors are unresectable), treatment is palliative and typically involves chemotherapy, biologic therapy, and/or immune checkpoint inhibition. In recent years, the use of adoptive T-cell therapy (ACT), leveraging the body’s own immune system to recognize and target cancer, has become increasingly popular. Unfortunately, while ACT has been successful in the treatment of hematological malignancies, it is less efficacious in advanced CRC due in part to a lack of productive immune infiltrate. This systematic review was conducted to summarize the current data for the efficacy and safety of ACT in advanced CRC. We report that ACT is well tolerated in patients with advanced CRC. Favorable survival estimates among patients with advanced CRC receiving ACT demonstrate promise for this novel treatment paradigm. However, additional stage I/II clinical trials are needed to establish the efficacy and safety of ACT in patients with CRC.

Phase I Clinical Trial of an Autologous Dendritic Cell Vaccine Against HER2 Shows Safety and Preliminary Clinical Efficacy

BACKGROUND

Despite recent advances, there is an urgent need for agents targeting HER2-expressing cancers other than breast cancer. We report a phase I study (NCT01730118) of a dendritic cell (DC) vaccine targeting HER2 in patients with metastatic cancer or bladder cancer at high risk of relapse.

PATIENTS AND METHODS

Part 1 of the study enrolled patients with HER2-expressing metastatic cancer that had progressed after at least standard treatment and patients who underwent definitive treatment for invasive bladder cancer with no evidence of disease at the time of enrollment. Part 2 enrolled patients with HER2-expressing metastatic cancer who had progressed after anti-HER2 therapy. The DC vaccines were prepared from autologous monocytes and transduced with an adenoviral vector expressing the extracellular and transmembrane domains of HER2 (AdHER2). A total of five doses were planned, and adverse events were recorded in patients who received at least one dose. Objective response was evaluated by unidimensional immune-related response criteria every 8 weeks in patients who received at least two doses. Humoral and cellular immunogenicity were assessed in patients who received more than three doses.

RESULTS

A total of 33 patients were enrolled at four dose levels (5 × 10⁶, 10 × 10⁶, 20 × 10⁶, and 40 × 10⁶ DCs). Median follow-up duration was 36 weeks (4-124); 10 patients completed five doses. The main reason for going off-study was disease progression. The main adverse events attributable to the vaccine were injection-site reactions. No cardiac toxicity was noted. Seven of 21 evaluable patients (33.3%) demonstrated clinical benefit (1 complete response, 1 partial response, and 5 stable disease). After ≥3 doses, an antibody response was detected in 3 of 13 patients (23.1%), including patients with complete and partial responses. Lymphocytes from 10 of 11 patients (90.9%) showed induction of anti-HER2 responses measured by the production of at least one of interferon-gamma, granzyme B, or tumor necrosis factor-alpha, and there were multifunctional responses in 8 of 11 patients (72.7%).

CONCLUSIONS

The AdHER2 DC vaccine showed evidence of immunogenicity and preliminary clinical benefit in patients with HER2-expressing cancers, along with an excellent safety profile. It shows promise for further clinical applications, especially in combination regimens.

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.

Heart Failure Therapies for the Prevention of HER2-Monoclonal Antibody-Mediated Cardiotoxicity: A Systematic Review and Meta-Analysis of Randomized Trials

Simple Summary

Monoclonal antibodies targeting HER2 are used for the management of early and metastatic HER2-positive breast cancer. Approximately 10–15% of patients diagnosed with breast cancer will be HER2-positive. The incidence of heart failure in breast cancer patients is becoming increasingly problematic, owing to the ageing of the population and the growing number of cancer survivors. The aim of our review was to assess the published evidence for the use of cardio-prevention strategies in HER2-monoclonal antibody-mediated cardiotoxicity. Whilst in the assessed trials the use of heart failure therapies did not reduce the risk of trastuzumab-associated cardiotoxicity, there was a reduction in the mean change in LVEF and in the rates of interruptions to HER2 therapy in patients treated with beta-blockers. This highlights the possible applications for neurohormonal therapies to prevent cardiotoxicity and mitigate interruption to vital HER2-monoclonal antibody treatment.

Abstract

Monoclonal antibodies including trastuzumab, pertuzumab, and antibody-drug conjugates, form the backbone of HER2-positive breast cancer therapy. Unfortunately, an important adverse effect of these agents is cardiotoxicity, occurring in approximately 10% of patients. There is increasing published data regarding prevention strategies for cardiotoxicity, though seldom used in clinical practice. We performed a systematic review and meta-analysis of randomized-controlled trials to evaluate pharmacotherapy for the prevention of monoclonal HER2-directed antibody-induced cardiotoxicity in patients with breast cancer. Online databases were queried from their inception until October 2021. Effects were determined by calculating risk ratios (RRs) and 95% confidence intervals (CI) or mean differences (MD) using random-effects models. We identified five eligible trials. In the three trials (n = 952) reporting data on the primary outcome of cardiotoxicity, there was no clear effect for patients assigned active treatment compared to control (RR = 0.90, 95% CI 0.63 to 1.29, p = 0.57). Effects were similar for ACE-I/ARB and beta-blockers (p homogeneity = 0.50). Active treatment reduced the risk of HER2 therapy interruptions (RR = 0.57, 95% CI 0.43 to 0.77, p < 0.001) with similar findings for ACE-I/ARB and beta-blockers (p homogeneity = 0.97). Prophylactic treatment with ACE-I/ARB or beta-blocker therapy may be of value for cardio-protection in patients with breast cancer prescribed monoclonal antibodies. Further, adequately powered randomized trials are required to define the role of routine prophylactic treatment in this patient group.

Trastuzumab does not bind rat or mouse ErbB2/neu: implications for selection of non-clinical safety models for trastuzumab-based therapeutics

PURPOSE

Assessment of non-clinical safety signals relies on understanding species selectivity of antibodies. This is particularly important with antibody-drug conjugates, where it is key to determine target-dependent versus target-independent toxicity. Although it appears to be widely accepted that trastuzumab does not bind mouse or rat HER2/ErbB2/neu, numerous investigators continue to use mouse models to investigate safety signals of trastuzumab and trastuzumab emtansine (T-DM1). We, therefore, conducted a broad array of both binding and biologic studies to demonstrate selectivity of trastuzumab for human HER2 versus mouse/rat neu.

METHODS

Binding of anti-neu and anti-HER2 antibodies was assessed by ELISA, FACS, IHC, Scatchard, and immunoblot methods in human, rat, and mouse cell lines. In human hepatocytes, T-DM1 uptake and catabolism were measured by LC-MS/MS; cell viability changes were determined using CellTiter-Glo.

RESULTS

Our data demonstrate, using different binding methods, lack of trastuzumab binding to rat or mouse neu. Structural studies show important amino acid differences in the trastuzumab-HER2 binding interface between mouse/rat and human HER2 ECD. Substitution of these rodent amino acid residues into human HER2 abolish binding of trastuzumab. Cell viability changes, uptake, and catabolism of T-DM1 versus a DM1 non-targeted control ADC were comparable, indicating target-independent effects of the DM1-containing ADCs. Moreover, trastuzumab binding to human or mouse hepatocytes was not detected.

CONCLUSIONS

These data, in total, demonstrate that trastuzumab, and by extension T-DM1, do not bind rat or mouse neu, underscoring the importance of species selection for safety studies investigating trastuzumab or trastuzumab-based therapeutics.

The mechanistic insights of the arrhythmogenic effect of trastuzumab

Cardiovascular diseases and cancers are the leading causes of deaths globally, and an increasing proportion of cancer patients is suffering from cardiac adverse effects of chemotherapeutic drugs. Trastuzumab, a monoclonal antibody that inhibits the activity of the human epidermal growth factor receptor 2 (HER2), is a potent targeted therapy for HER2-positive malignancies. Despite the impressive antineoplastic efficacy, the cardiotoxicity of trastuzumab frequently limits its use. Trastuzumab-induced cardiac contractile dysfunction has been extensively studied, yet the electrophysiological side effect of trastuzumab remains poorly characterized. Growing evidence from basic and clinical studies supports the link between trastuzumab treatment and arrhythmias. This review comprehensively summarizes relevant information from those reports, discusses their limitations, and suggests future research directions. We aim to encourage further investigations that will provide valuable insights to devise cardioprotective strategies against trastuzumab-induced cardiotoxicity.

Improving target assessment in biomedical research: the GOT-IT recommendations

Academic research plays a key role in identifying new drug targets, including understanding target biology and links between targets and disease states. To lead to new drugs, however, research must progress from purely academic exploration to the initiation of efforts to identify and test a drug candidate in clinical trials, which are typically conducted by the biopharma industry. This transition can be facilitated by a timely focus on target assessment aspects such as target-related safety issues, druggability and assayability, as well as the potential for target modulation to achieve differentiation from established therapies. Here, we present recommendations from the GOT-IT working group, which have been designed to support academic scientists and funders of translational research in identifying and prioritizing target assessment activities and in defining a critical path to reach scientific goals as well as goals related to licensing, partnering with industry or initiating clinical development programmes. Based on sets of guiding questions for different areas of target assessment, the GOT-IT framework is intended to stimulate academic scientists' awareness of factors that make translational research more robust and efficient, and to facilitate academia-industry collaboration.

Intermittent left bundle branch block and acute heart failure in trastuzumab-induced cardiotoxicity

A 70-year-old woman with HER2+/ER+ breast cancer on adjuvant trastuzumab therapy without a history of cardiovascular disease presented with respiratory failure from influenza and was found to have intermittent left bundle branch block (LBBB) with new onset systolic heart failure. Her course was complicated by polymorphic ventricular tachycardia and recurrent chest pain. Significant investigations included a normal cardiac MRI and cardiac catheterisation with unobstructed coronaries. It was determined that the aetiology of her heart failure was trastuzumab-induced cardiotoxicity after comprehensive workup. This case highlights an uncommon presentation of LBBB and the steps taken to diagnose a rare cardiomyopathy.

Precision Cardio-Oncology: a Systems-Based Perspective on Cardiotoxicity of Tyrosine Kinase Inhibitors and Immune Checkpoint Inhibitors

Cancer therapies have been evolving from conventional chemotherapeutics to targeted agents. This has fulfilled the hope of greater efficacy but unfortunately not of greater safety. In fact, a broad spectrum of toxicities can be seen with targeted therapies, including cardiovascular toxicities. Among these, cardiomyopathy and heart failure have received greatest attention, given their profound implications for continuation of cancer therapies and cardiovascular morbidity and mortality. Prediction of risk has always posed a challenge and even more so with the newer targeted agents. The merits of accurate risk prediction, however, are very evident, e.g. facilitating treatment decisions even before the first dose is given. This is important for agents with a long half-life and high potential to induced life-threatening cardiac complications, such as myocarditis with immune checkpoint inhibitors. An opportunity to address these needs in the field of cardio-oncology is provided by the expanding repertoire of "-omics" and other tools in precision medicine and their integration in a systems biology approach. This may allow for new insights into patho-mechanisms and the creation of more precise and cost-effective risk prediction tools with the ultimate goals of improved therapy decisions and prevention of cardiovascular complications. Herein, we explore this topic as a future approach to translating the complexity of cardio-oncology to the reality of patient care.

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.

Human-Induced Pluripotent Stem Cell Model of Trastuzumab-Induced Cardiac Dysfunction in Patients With Breast Cancer

BACKGROUND

Molecular targeted chemotherapies have been shown to significantly improve the outcomes of patients who have cancer, but they often cause cardiovascular side effects that limit their use and impair patients' quality of life. Cardiac dysfunction induced by these therapies, especially trastuzumab, shows a distinct cardiotoxic clinical phenotype in comparison to the cardiotoxicity induced by conventional chemotherapies.

METHODS

We used the human induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) platform to determine the underlying cellular mechanisms in trastuzumab-induced cardiac dysfunction. We assessed the effects of trastuzumab on structural and functional properties in iPSC-CMs from healthy individuals and performed RNA-sequencing to further examine the effect of trastuzumab on iPSC-CMs. We also generated human induced pluripotent stem cells from patients receiving trastuzumab and examined whether patients' phenotype could be recapitulated in vitro by using patient-specific iPSC-CMs.

RESULTS

We found that clinically relevant doses of trastuzumab significantly impaired the contractile and calcium-handling properties of iPSC-CMs without inducing cardiomyocyte death or sarcomeric disorganization. RNA-sequencing and subsequent functional analysis revealed mitochondrial dysfunction and altered the cardiac energy metabolism pathway as primary causes of trastuzumab-induced cardiotoxic phenotype. Human iPSC-CMs generated from patients who received trastuzumab and experienced severe cardiac dysfunction were more vulnerable to trastuzumab treatment than iPSC-CMs generated from patients who did not experience cardiac dysfunction following trastuzumab therapy. It is important to note that metabolic modulation with AMP-activated protein kinase activators could avert the adverse effects induced by trastuzumab.

CONCLUSIONS

Our results indicate that alterations in cellular metabolic pathways in cardiomyocytes could be a key mechanism underlying the development of cardiac dysfunction following trastuzumab therapy; therefore, targeting the altered metabolism may be a promising therapeutic approach for trastuzumab-induced cardiac dysfunction.

T-cell Activating Tribodies as a Novel Approach for Efficient Killing of ErbB2-positive Cancer Cells

The Tyrosine Kinase Receptor ErbB2 (HER2) when overexpressed in breast cancer (BC) is associated with poor prognosis. The monoclonal antibody Trastuzumab has become a standard treatment of ErbB2+BC. The antibody treatment has limited efficacy, often meets resistance and induces cardiotoxicity. T-cell recruiting bispecific antibody derivatives (TRBA) offer a more effective alternative to standard antibody therapy. We evaluated a panel of TRBAs targeting 3 different epitopes on the ErbB2 receptor either in a bivalent targeting tribody structure or as a monovalent scFv-fusion (BiTE format) for binding, cytotoxicity on Trastuzumab-resistant cell lines, and induction of cardiotoxicity. All three TRBAs bind with high affinity to the ErbB2 extracellular domain and a large panel of ErbB2-positive tumor cells. Tribodies had an increased in vitro cytotoxic potency as compared to BiTEs. It is interesting to note that, Tribodies targeting the epitopes on ErbB2 receptor domains I and II bind and activate lysis of mammary and gastric tumor cells more efficiently than a Tribody targeting the Trastuzumab epitope on domain IV. The first 2 are also active on Trastuzumab-resistant cancer cells lacking or masking the epitope recognized by Trastuzumab. None of the Tribodies studied showed significant toxicity on human cardiomyocytes. Altogether these results make these novel anti-ErbB2 bispecific Tribodies candidates for therapeutic development for treating ErbB2-positive Trastuzumab-resistant cancer patients.

Trastuzumab-Induced Cardiomyopathy and Intermittent Left Bundle Branch Block

Trastuzumab-induced cardiomyopathy is a known complication of its use in breast cancer treatment, but it remains mostly asymptomatic and often reversible. Non-myopathic cardiac complications have been rarely reported with trastuzumab. These include left and right bundle branch block, arrhythmias and sinus node dysfunction. We report a case of a 52-year-old female breast cancer patient with trastuzumab-induced asymptomatic intermittent left bundle branch block recurring nearly a year after the initial diagnosis and resolution of trastuzumab-related cardiomyopathy.

Cardiotoxicity and pro-inflammatory effects of the immune checkpoint inhibitor Pembrolizumab associated to Trastuzumab

BACKGROUND

The immunotherapy has revolutionized the world of oncology in the last decades with considerable advantages in terms of overall survival in cancer patients. The association of Pembrolizumab and Trastuzumab was recently proposed in clinical trials for the treatment of Trastuzumab-resistant advanced HER2-positive breast cancer. Although immunotherapies are frequently associated with a wide spectrum of immune-related adverse events, the cardiac toxicity has not been properly studied.

PURPOSE

We studied, for the first time, the putative cardiotoxic and pro-inflammatory effects of Pembrolizumab associated to Trastuzumab.

METHODS

Cell viability, intracellular calcium quantification and pro-inflammatory studies (analyses of the production of Interleukin 1β, 6 and 8, the expression of NF-kB and Leukotriene B4) were performed in human fetal cardiomyocytes. Preclinical studies were also performed in C57BL6 mice by analyzing fibrosis and inflammation in heart tissues.

RESULTS

The combination of Pembrolizumab and Trastuzumab leads to an increase of the intracellular calcium overload (of 3 times compared to untreated cells) and to a reduction of the cardiomyocytes viability (of 65 and 20-25%, compared to untreated and Pembrolizumab or Trastuzumab treated cells, respectively) indicating cardiotoxic effects. Notably, combination therapy increases the inflammation of cardiomyocytes by enhancing the expression of NF-kB and Interleukins. Moreover, in preclinical models, the association of Pembrolizumab and Trastuzumab increases the Interleukins expression of 40-50% compared to the single treatments; the expression of NF-kB and Leukotriene B4 was also increased.

CONCLUSION

Pembrolizumab associated to Trastuzumab leads to strong cardiac pro-inflammatory effects mediated by overexpression of NF-kB and Leukotriene B4 related pathways.

Cardiac GPCR-Mediated EGFR Transactivation: Impact and Therapeutic Implications

G protein-coupled receptors (GPCRs) remain primary therapeutic targets for numerous cardiovascular disorders, including heart failure (HF), because of their influence on cardiac remodeling in response to elevated neurohormone signaling. GPCR blockers have proven to be beneficial in the treatment of HF by reducing chronic G protein activation and cardiac remodeling, thereby extending the lifespan of patients with HF. Unfortunately, this effect does not persist indefinitely, thus next-generation therapeutics aim to selectively block harmful GPCR-mediated pathways while simultaneously promoting beneficial signaling. Transactivation of epidermal growth factor receptor (EGFR) has been shown to be mediated by an expanding repertoire of GPCRs in the heart, and promotes cardiomyocyte survival, thus may offer a new avenue of HF therapeutics. However, GPCR-dependent EGFR transactivation has also been shown to regulate cardiac hypertrophy and fibrosis by different GPCRs and through distinct molecular mechanisms. Here, we discuss the mechanisms and impact of GPCR-mediated EGFR transactivation in the heart, focusing on angiotensin II, urotensin II, and β-adrenergic receptor systems, and highlight areas of research that will help us to determine whether this pathway can be engaged as future therapeutic strategy.

Pathophysiology of cardiotoxicity from target therapy and angiogenesis inhibitors

The progress in cancer therapy and the increase in number of long-term survivors reveal the issue of cardiovascular side-effects of anticancer drugs. Cardiotoxicity has become a significant problem, and the risks of adverse cardiac events induced by systemic drugs need to be seriously considered. Potential cardiovascular toxicities linked to anticancer agents include arrhythmias, myocardial ischemia and infarction, hypertension, thromboembolism, left ventricular dysfunction, and heart failure. It has been shown that several anticancer drugs seriously affect the cardiovascular system, such as ErbB2 inhibitors, vascular endothelial growth factor (VEGF) inhibitors, multitargeted kinase inhibitors, Abelson murine leukemia viral oncogene homolog inhibitors, and others. Each of these agents has a different mechanism through which it affects the cardiovascular system. ErbB2 inhibitors block the ErbB4/ErbB2 heterodimerization pathway triggered by Neuregulin-1, which is essential for cardiomyocyte survival. VEGF signaling is crucial for vascular growth, but it also has a major impact on myocardial function, and the VEGF pathway is also essential for maintenance of cardiovascular homeostasis. Drugs that inhibit the VEGF signaling pathway lead to a net reduction in capillary density and loss of contractile function. Here, we review the mechanisms and pathophysiology of the most significant cardiotoxic effects of ErbB2 inhibitors and antiangiogenic drugs. Moreover, we highlight the role of cardioncology in recognizing these toxicities, developing strategies to prevent or minimize cardiovascular toxicity, and reducing long-term cardiotoxic effects.

Breakthroughs in modern cancer therapy and elusive cardiotoxicity: Critical research-practice gaps, challenges, and insights

To date, five cancer treatment modalities have been defined. The three traditional modalities of cancer treatment are surgery, radiotherapy, and conventional chemotherapy, and the two modern modalities include molecularly targeted therapy (the fourth modality) and immunotherapy (the fifth modality). The cardiotoxicity associated with conventional chemotherapy and radiotherapy is well known. Similar adverse cardiac events are resurging with the fourth modality. Aside from the conventional and newer targeted agents, even the most newly developed, immune-based therapeutic modalities of anticancer treatment (the fifth modality), e.g., immune checkpoint inhibitors and chimeric antigen receptor (CAR) T-cell therapy, have unfortunately led to potentially lethal cardiotoxicity in patients. Cardiac complications represent unresolved and potentially life-threatening conditions in cancer survivors, while effective clinical management remains quite challenging. As a consequence, morbidity and mortality related to cardiac complications now threaten to offset some favorable benefits of modern cancer treatments in cancer-related survival, regardless of the oncologic prognosis. This review focuses on identifying critical research-practice gaps, addressing real-world challenges and pinpointing real-time insights in general terms under the context of clinical cardiotoxicity induced by the fourth and fifth modalities of cancer treatment. The information ranges from basic science to clinical management in the field of cardio-oncology and crosses the interface between oncology and onco-pharmacology. The complexity of the ongoing clinical problem is addressed at different levels. A better understanding of these research-practice gaps may advance research initiatives on the development of mechanism-based diagnoses and treatments for the effective clinical management of cardiotoxicity.

Cardiotoxicity of ErbB2-targeted therapies and its impact on drug development, a spotlight on trastuzumab

INTRODUCTION

Trastuzumab, a therapeutic monoclonal antibody directed against ErbB2, is often noted as a successful example of targeted therapy. Trastuzumab improved outcomes for many patients with ErbB2-positive breast and gastric cancers, however, cardiac side effects [e.g., left ventricular dysfunction and congestive heart failure (CHF)] were reported in the early phase clinical studies. This finding, subsequently corroborated by multiple clinical studies, raised concerns that the observed cardiotoxicity induced by trastuzumab might adversely impact the clinical development of other therapeutics targeting ErbB family members. Areas covered: In this review we summarize both basic research and clinical findings regarding trastuzumab-induced cardiotoxicity and assess if there has been an impact of trastuzumab-induced cardiotoxicity on the development of other agents targeting ErbB family members. Expert opinion: There are a number of scientific gaps that are critically important to address for the continued success of HER2-targeted agents. These include: 1) elucidating the molecular mechanisms contributing to cardiotoxicity; 2) developing relevant preclinical testing systems for predicting cardiotoxicity; 3) developing clinical strategies to identify patients at risk of cardiotoxicity; and 4) enhancing management of clinical symptoms of cardiotoxicity.

Cardiac Safety of Dual Anti-HER2 Therapy in the Neoadjuvant Setting for Treatment of HER2-Positive Breast Cancer

BACKGROUND

Trastuzumab and pertuzumab are approved for the neoadjuvant treatment of human epidermal growth receptor 2 (HER2)-positive breast cancer, but cardiac safety data is limited. We report the cardiac safety of dose-dense doxorubicin and cyclophosphamide (AC) followed by paclitaxel, trastuzumab, and pertuzumab (THP) in the neoadjuvant setting followed by adjuvant trastuzumab-based therapy.

METHODS

Fifty-seven patients treated with neoadjuvant dose-dense AC-THP followed by adjuvant trastuzumab-based therapy between September 1, 2013, and March 1, 2015, were identified. The primary outcome was cardiac event rate, defined by heart failure (New York Heart Association [NYHA] class III/IV) or cardiac death. Patients underwent left ventricular ejection fraction (LVEF) monitoring at baseline, after AC, and serially during 1 year of anti-HER2 therapy.

RESULTS

The median age was 46 years (range 26-68). Two (3.5%) patients developed NYHA class III/IV heart failure 5 and 9 months after initiation of trastuzumab-based therapy, leading to permanent discontinuation of anti-HER2 treatment. Seven (12.3%) patients developed a significant LVEF decline (without NYHA class III/IV symptoms). The median LVEF was 65% (range 55%-75%) at baseline and 64% (range 53%-72%) after AC, and decreased to 60% (range 35%-70%), 60% (range 23%-73%), 61% (range 25%-73%), and 58% (range 28%-66%) after 3, 6, 9, and 12 months (± 6 weeks) of trastuzumab-based therapy.

CONCLUSION

The incidence of NYHA class III/IV heart failure after neoadjuvant AC-THP (followed by adjuvant trastuzumab-based therapy) is comparable to rates reported in trials of sequential doxorubicin and trastuzumab. Our findings do not suggest an increased risk of cardiotoxicity from trastuzumab plus pertuzumab following a doxorubicin-based regimen.

IMPLICATIONS FOR PRACTICE

Dual anti-human epidermal growth receptor 2 (HER2) therapy with trastuzumab and pertuzumab combined with standard chemotherapy has received accelerated approval for the neoadjuvant treatment of stage II-III HER2-positive breast cancer. Cardiac safety data for trastuzumab and pertuzumab in this setting are limited to clinical trials that utilized epirubicin-based chemotherapy. Formalized investigations into the cardiac safety of trastuzumab and pertuzumab with doxorubicin- (rather than epirubicin) based regimens are important because these regimens are widely used for the adjuvant and neoadjuvant treatment of breast cancer. The known role of HER2 signaling in the physiological adaptive responses of the heart provides further rationale for study on the potential cardiotoxicity of dual anti-HER2 blockade. Findings from this retrospective study provide favorable preliminary data on the cardiac safety of trastuzumab and pertuzumab in combination with a regimen of neoadjuvant doxorubicin and cyclophosphamide followed by paclitaxel, one of the preferred breast cancer treatment regimens, according to the National Comprehensive Cancer Network.

Cardiovascular imaging in the diagnosis and monitoring of cardiotoxicity: cardiovascular magnetic resonance and nuclear cardiology

Chemotherapy-induced cardiotoxicity (CTX) is a determining factor for the quality of life and mortality of patients administered potentially cardiotoxic drugs and in long-term cancer survivors. Therefore, prevention and early detection of CTX are highly desirable, as is the exploration of alternative therapeutic strategies and/or the proposal of potentially cardioprotective treatments. In recent years, cardiovascular imaging has acquired a pivotal role in this setting. Although echocardiography remains the diagnostic method most used to monitor cancer patients, the need for more reliable, reproducible and accurate detection of early chemotherapy-induced CTX has encouraged the introduction of second-line advanced imaging modalities, such as cardiac magnetic resonance (CMR) and nuclear techniques, into the clinical setting. This review of the Working Group on Drug Cardiotoxicity and Cardioprotection of the Italian Society of Cardiology aims to afford an overview of the most important findings from the literature about the role of CMR and nuclear techniques in the management of chemotherapy-treated patients, describe conventional and new parameters for detecting CTX from both diagnostic and prognostic perspectives and provide integrated insight into the role of CMR and nuclear techniques compared with other imaging tools and versus the positions of the most important international societies.

Antineoplastic-related cardiotoxicity, morphofunctional aspects in a murine model: contribution of the new tool 2D-speckle tracking

OBJECTIVE

Considering that global left ventricular systolic radial strain is a sensitive technique for the early detection of left ventricular dysfunction due to antineoplastics and the analysis of segmental myocardial contractility, we evaluated this technique for early detection of trastuzumab-related cardiotoxicity by comparing it with cardiac structural damage.

METHODS

Groups of six mice were injected with trastuzumab or doxorubicin, used either as single agents or in combination. Cardiac function was evaluated by transthoracic echocardiography measurements before and after treatment for 2 or 7 days, by using a Vevo 2100 high-resolution imaging system. After echocardiography, mice were euthanized, and hearts were processed for histological evaluations, such as cardiac fibrosis, apoptosis, capillary density, and inflammatory response.

RESULTS

Trastuzumab-related cardiotoxicity was detected early by 2D strain imaging. Radial strain was reduced after 2 days in mice treated with trastuzumab alone (21.2%±8.0% vs 40.5%±4.8% sham; P<0.01). Similarly, trastuzumab was found to induce apoptosis, capillary density reduction, and inflammatory response in cardiac tissue after 2 days of treatment, in a fashion similar to doxorubicin. On the contrary, fractional shortening reduction and cardiac fibrosis were observed only after 7 days of trastuzumab treatment, in contrast to doxorubicin treatment which induced early fibrosis and fractional shortening reduction.

CONCLUSION

The reduction of left ventricular systolic strain after 2 days of trastuzumab treatment may indicate early myocardial functional damage before the reduction in left ventricular ejection fraction and this early dysfunction is well correlated with structural myocardial damage, such as apoptosis and inflammatory response. Fractional shortening reduction after 7 days of trastuzumab treatment is related to fibrosis in cardiac tissue.

ErbB2 signaling at the crossing between heart failure and cancer

The dual role of ErbB2 (or HER-2) in tumor growth and in physiological adaptive reactions of the heart positions ErbB2 at the intersection between cancer and chronic heart failure. Accordingly, ErbB2-targeted inhibitory therapy of cancer may lead to ventricular dysfunction, and activation of ErbB2 for heart failure therapy may induce malignancy. The molecular processes leading to the activation of ErbB2 in tumors and cardiac cells are, however, fundamentally different from each other. Thus, it must be feasible to design drugs that specifically target either physiological or malignant ErbB2 signaling, to activate ErbB2 signaling in heart failure with no increased risk for cancer, and to inhibit ErbB2 signaling in cancer with no increased risk for heart failure. In this review, we present a state-of-the-art on how ErbB2 is regulated in physiological conditions and in tumor cells and how this knowledge translates into smart drug design. This leads to a new generation of drugs interfering with ErbB2 in a unique way tailored for a specific clinical goal. These exciting developments at the crossing between cancer and heart failure are an elegant example of interdisciplinary collaborations between clinicians, physiologists, pharmacologists, and molecular biologists.

Chronic stress and excessive glucocorticoid exposure both lead to altered Neuregulin-1/ErbB signaling in rat myocardium

Exposure to chronic stress or excess glucocorticoids is associated with the development of depression and heart disease, but the underlying mechanisms remain equivocal. While recent evidence has indicated that Neuregulin-1 (NRG1) and its ErbB receptors play an essential role in cardiac function, much is still unknown concerning the biological link between NRG1/ErbB pathway and the stress-induced comorbidity of depression and cardiac dysfunction. Therefore, we examined the protein expression of NRG1 and ErbB receptors in the myocardium of rats following chronic unpredictable mild stress (CUMS) or rats treated with two different doses (0.2 and 2mg/kg/day, respectively) of dexamethasone (Dex). The stressed rats showed elevated expression of NRG1 and phosphorylated ErbB4 (pErbB4) in the myocardium, whereas ErbB2 and pErbB2 were inhibited. The lower dose of Dex enhanced myocardial NRG1/ErbB signaling, but as the dose is increased, while ErbB4 remained activated, the expression of ErbB2 and pErbB2 became compromised. Both CUMS and 2mg/kg of Dex suppressed the downstream Akt and ERK phosphorylation. Although the lower dose of Dex increased myocardial antiapoptotic Bcl-xl expression, a significant decrease of Bcl-xl expression was found in rats treated with the higher dose. Meanwhile, both CUMS and two different doses of Dex induced proapoptotic Bax level. Combined, our data firstly showed (mal)adaptive responses of NRG1/ErbB system in the stressed heart, indicating the potential involvement of NRG1/ErbB pathway in the stress-induced cardiac dysfunction.

Cardiotoxicity associated with targeted cancer therapies

Compared with traditional chemotherapy, targeted cancer therapy is a novel strategy in which key molecules in signaling pathways involved in carcinogenesis and tumor spread are inhibited. Targeted cancer therapy has fewer adverse effects on normal cells and is considered to be the future of chemotherapy. However, targeted cancer therapy-induced cardiovascular toxicities are occasionally critical issues in patients who receive novel anticancer agents, such as trastuzumab, bevacizumab, sunitinib and imatinib. The aim of this review was to discuss these most commonly used drugs and associated incidence of cardiotoxicities, including left ventricular dysfunction, heart failure, hypertension and thromboembolic events, as well as summarize their respective molecular mechanisms of cardiovascular adverse effects.

Trastuzumab and target-therapy side effects: Is still valid to differentiate anthracycline Type I from Type II cardiomyopathies?

The improvement in cancer therapy and the increasing number of long term survivors unearth the issue of cardiovascular side effects of anticancer treatments. As a paradox in cancer survivors, delayed cardiotoxicity has emerged as a significant problem. Two categories of cardiotoxic side effects of antineoplastic drugs have been previously proposed: Type I cardiotoxicity, defined as permanent cardiotoxicity, is usually caused by anthracyclines; Type II cardiotoxicity, considered as reversible cardiotoxicity, has been mainly related to monoclonal antibodies. The cardiotoxicity of antibodies has been associated to trastuzumab, a humanized anti-ErbB2 monoclonal antibody currently in clinical use for the therapy of breast carcinomas, which induces cardiac dysfunction when used in monotherapy, or in combination with anthracyclines. Furthermore, recent retrospective studies have shown an increased incidence of heart failure and/or cardiomyopathy in patients treated with trastuzumab, that can persist many years after the conclusion of the therapy, thus suggesting that the side toxic effects are not always reversible as it was initially proposed. On the other hand, early detection and prompt therapy of anthracycline associated cardiotoxicity can lead to substantial recovery of cardiac function. On the basis of these observations, we propose to find a new different classification for cardiotoxic side effects of drugs used in cancer therapy.

Toxicology Strategies for Drug Discovery: Present and Future

Attrition due to nonclinical safety represents a major issue for the productivity of pharmaceutical research and development (R&D) organizations, especially during the compound optimization stages of drug discovery and the early stages of clinical development. Focusing on decreasing nonclinical safety-related attrition is not a new concept, and various approaches have been experimented with over the last two decades. Front-loading testing funnels in Discovery with in vitro toxicity assays designed to rapidly identify unfavorable molecules was the approach adopted by most pharmaceutical R&D organizations a few years ago. However, this approach has also a non-negligible opportunity cost. Hence, significant refinements to the "fail early, fail often" paradigm have been proposed recently to reflect the complexity of accurately categorizing compounds with early data points without taking into account other important contextual aspects, in particular efficacious systemic and tissue exposures. This review provides an overview of toxicology approaches and models that can be used in pharmaceutical Discovery at the series/lead identification and lead optimization stages to guide and inform chemistry efforts, as well as a personal view on how to best use them to meet nonclinical safety-related attrition objectives consistent with a sustainable pharmaceutical R&D model. The scope of this review is limited to small molecules, as large molecules are associated with challenges that are quite different. Finally, a perspective on how several emerging technologies may impact toxicity evaluation is also provided.

Contemporary Breast Radiotherapy and Cardiac Toxicity

Long-term cardiac effects are an important component of survivorship after breast radiotherapy. The pathophysiology of cardiotoxicity, history of breast radiotherapy, current methods of cardiac avoidance, modern outcomes, context of historical outcomes, quantifying cardiac effects, and future directions are reviewed in this article. Radiation-induced oxidative stress induces proinflammatory cytokines and is a process that potentiates late effects of fibrosis and intimal proliferation in endothelial vasculature. Breast radiation therapy has changed substantially in recent decades. Several modern technologies exist to improve cardiac avoidance such as deep inspiration breath hold, gating, accelerated partial breast irradiation, and use of modern 3-dimensional planning. Modern outcomes may vary notably from historical long-term cardiac outcomes given the differences in cardiac dose with modern techniques. Methods of quantifying radiation-related cardiotoxicity that correlate with future cardiac risks are needed with current data exploring techniques such as measuring computed tomography coronary artery calcium score, single-photon emission computed tomography imaging, and biomarkers. Placing historical data, dosimetric correlations, and relative cardiac risk in context are key when weighing the benefits of radiotherapy in breast cancer control and survival. Estimating present day cardiac risk in the modern treatment era includes challenges in length of follow-up and the use of confounding cardiotoxic agents such as evolving systemic chemotherapy and targeted therapies. Future directions in both multidisciplinary management and advancing technology in radiation oncology may provide further improvements in patient risk reduction and breast cancer survivorship.

Use of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes (hiPSC-CMs) to Monitor Compound Effects on Cardiac Myocyte Signaling Pathways

There is a need to develop mechanism-based assays to better inform risk of cardiotoxicity. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are rapidly gaining acceptance as a biologically relevant in vitro model for use in drug discovery and cardiotoxicity screens. Utilization of hiPSC-CMs for mechanistic investigations would benefit from confirmation of the expression and activity of cellular pathways that are known to regulate cardiac myocyte viability and function. This unit describes an approach to demonstrate the presence and function of signaling pathways in hiPSC-CMs and the effects of treatments on these pathways. We present a workflow that employs protocols to demonstrate protein expression and functional integrity of signaling pathway(s) of interest and to characterize biological consequences of signaling modulation. These protocols utilize a unique combination of structural, functional, and biochemical endpoints to interrogate compound effects on cardiomyocytes.

Comparison of the long term cardiac effects associated with 9 and 52 weeks of trastuzumab in HER2-positive early breast cancer

PURPOSE

Trastuzumab induced cardiotoxicity (TIC) was defined as the most serious side effect. Long term cardiac effects of trastuzumab are still not known, thus we aimed to compare the long term cardiac effects of adjuvant trastuzumab therapies of HER2-positive breast cancer according to the treatment duration.

METHODS

Patients who completed adjuvant trastuzumab treatment at least 6 months before for the adjuvant setting in HER2-positive breast cancer were included in the study. A total of 164 patients were included in this study: 108 and 56 patients were treated with 9 weeks and 52 weeks of trastuzumab, respectively. The main limitation of our study is that due to the cross-sectional evaluation of cardiac biomarkers we cannot predict the status of baseline cardiac biomarkers of this population.

RESULTS

The median follow-up of the study was 32 (10-95) months. The accompanying chronic diseases were similar in both groups. Baseline left ventricular ejection fraction (LVEF) was 65.5 ± 3.4% vs 67.1 ± 4.5% in the 9 weeks and 52 weeks trastuzumab treatment groups, respectively (p = 0.13). Symptomatic heart failure was not observed during trastuzumab treatment in either group. Trastuzumab induced cardiotoxicity (TIC) was observed in 2 (1.9%) and 17 (30.3%) patients in the 9 and 52 weeks trastuzumab treatment groups, respectively (p < 0.001). After a median 24 months of follow-up from the last dose of trastuzumab, mean LVEF values were similar between the two treatment arms (p = 0.29). In the subgroup analyses, mean LVEF values were significantly lower in patients who developed TIC compared to those who did not develop TIC (61.9 ± 3.6% vs 64.4 ± 2.6%, p = 0.04). Average mean LVEF loss from baseline was significantly higher in patients who developed TIC compared to those who did not develop TIC (10.0 ± 6.0% vs 1.5 ± 6.2%, p < 0.001). Cardiac biomarkers were similar in both treatment groups. In the subgroup analyses serum High-sensitivity C-reactive protein (hs-CRP) and prohormone brain natriuretic peptide (pro-BNP) levels were significantly higher in patients who developed TIC compared to those who did not develop TIC.

CONCLUSIONS

TIC was observed to be significantly higher in the 52 weeks trastuzumab group. At the end of 32 months of follow-up mean LVEF values and cardiac biomarkers were similar between the two treatment groups. In the subgroup analyses, significant LVEF loss and higher cardiac biomarkers which show cardiac damage in patients who developed TIC can be permanent in some of the patients and long term cardiac damage may be underestimated.

Prevention and Treatment of Cardiac Dysfunction in Breast Cancer Survivors

As recurrence free survival following a breast cancer diagnosis continues to improve, cardiovascular morbidity and mortality will assume greater importance in the breast cancer survivorship research agenda particularly for women receiving potentially cardiotoxic therapy. Development of (1) tools to readily identify pre-diagnostic risk factors for cardiac dysfunction, (2) well-tolerated prophylactic treatments to reduce the risk of cardiac injury, and (3) sensitive and affordable monitoring techniques which can identify subclinical toxicity prior to a drop in left ventricular ejection fraction are or should be focus areas of cardio-oncology research. Since weight as well as cardiorespiratory fitness generally decline after a breast cancer diagnosis, behavioral approaches which can improve energy balance and fitness are important to optimize cardiovascular health in all breast cancer survivors not just those undergoing cardiotoxic therapy. These goals are likely best achieved by partnerships between cardiologists, oncologists and internists such as those initiated with the formation of the International CardiOncology Society (ICOS) and the NCI Community Cardiotoxicity Task Force.

Monitoring Trastuzumab Resistance and Cardiotoxicity: A Tale of Personalized Medicine

While approval of trastuzumab, a recombinant monoclonal antibody directed against HER2, along with a diagnostic kit to detect breast cancers which are positive for HER2 overexpression, has advanced a new era of stratified and personalized medicine, it also created several challenges to our scientific and clinical practice. These problems include trastuzumab resistance and trastuzumab-induced cardiotoxicity. In this review, we will summarize data from the literature regarding mechanisms of trastuzumab resistance and trastuzumab-induced cardiotoxicity and present some promising model systems that may advance our understanding of these mechanisms. Our discussion will include development of circulating tumor cells and circulating tumor DNA for monitoring tumor burden, of patient-derived xenograft models for preclinical testing of novel therapies, and of novel therapeutic strategies for trastuzumab-resistance and possible integration of these strategies in the design of co-clinical studies for testing in relevant patient subpopulations.

Cardiac protective effects of dexrazoxane on animal cardiotoxicity model induced by anthracycline combined with trastuzumab is associated with upregulation of calpain-2

Cardiotoxicity is a well-recognized side effect induced by chemotherapeutic drugs such as anthracycline and trastuzumab through different mechanisms. Currently, accumulating evidence supports that dexrazoxane (DZR) can minimize the risk of cardiotoxicity. In this study, we investigated whether dexrzoxane could reduce cardiotoxicity in the treatment of anthracycline combined with trastuzumab. We randomly divided 90 experimental F344 rats into control group, chemotherapeutics and trastuzumab (doxorubicin [DOX] + herceptin [Her]) group, and chemotherapeutics, trastuzumab, and DZR (DOX + Her + DZR) group. Animal status and body weight, cardiac function, serum cardiac markers, cardiomyocyte apoptosis of the rats, and expression level of calpain-2 were evaluated. Left ventricular ejection fraction (LVEF) and fractional shortening (FS) of the left ventricle were observed. The serum levels of malondialdehyde (MDA) and cardiac troponin I (cTnI) and cardiomyocyte apoptosis were detected by enzyme linked immunosorbent assay and TdT-mediated dUTP nick end labeling assays. The mRNA and protein level of calpain-2 were measured by reverse transcriptase polymerase chain reaction and Western blot. We observed that the LVEF and FS of the left ventricle were significantly higher in the DOX + Her + DZR group than that in the DOX + Her group (P < 0.05). The serum levels of MDA and cTnI between DOX + Her group and DOX + Her + DZR group were significantly different. In addition, cardiomyocyte apoptosis in the DOX + Her + DZR group was significantly less severe than that in the DOX + Her group (P < 0.05). After DZR treatment, the calpain-2 mRNA and protein levels in the DOX + Her + DZR group were significantly higher than the DOX + Her group (P < 0.05). Our results suggest that DZR can effectively reduce the cardiotoxicity of combinatorial treatment of trastuzumab and anthracycline partly through upregulating calpain-2.

CLO: The cell line ontology

Background

Cell lines have been widely used in biomedical research. The community-based Cell Line Ontology (CLO) is a member of the OBO Foundry library that covers the domain of cell lines. Since its publication two years ago, significant updates have been made, including new groups joining the CLO consortium, new cell line cells, upper level alignment with the Cell Ontology (CL) and the Ontology for Biomedical Investigation, and logical extensions.

Construction and content

Collaboration among the CLO, CL, and OBI has established consensus definitions of cell line-specific terms such as ‘cell line’, ‘cell line cell’, ‘cell line culturing’, and ‘mortal’ vs. ‘immortal cell line cell’. A cell line is a genetically stable cultured cell population that contains individual cell line cells. The hierarchical structure of the CLO is built based on the hierarchy of the in vivo cell types defined in CL and tissue types (from which cell line cells are derived) defined in the UBERON cross-species anatomy ontology. The new hierarchical structure makes it easier to browse, query, and perform automated classification. We have recently added classes representing more than 2,000 cell line cells from the RIKEN BRC Cell Bank to CLO. Overall, the CLO now contains ~38,000 classes of specific cell line cells derived from over 200 in vivo cell types from various organisms.

Utility and discussion

The CLO has been applied to different biomedical research studies. Example case studies include annotation and analysis of EBI ArrayExpress data, bioassays, and host-vaccine/pathogen interaction. CLO’s utility goes beyond a catalogue of cell line types. The alignment of the CLO with related ontologies combined with the use of ontological reasoners will support sophisticated inferencing to advance translational informatics development.

Epidermal growth factor receptor signalling in keratinocyte biology: implications for skin toxicity of tyrosine kinase inhibitors

The epidermal growth factor receptor (EGFR) and its ligands have been long recognized as centrally involved in the growth and repair process of epithelia, as well as in carcinogenesis. In addition, the EGFR has been demonstrated to be importantly involved in the control of inflammatory responses. During this last decade, a number of highly specific agents targeting this system have become an integral component of pharmacologic strategies against many solid malignancies. These drugs have led to increased patient survival and made therapy more tolerant when compared to conventional cytotoxic drugs. Nonetheless, their use is associated with a constellation of toxic effects on the skin, including follicular pustules, persistent inflammation, xerosis and pruritus, and enhanced susceptibility to infections. This dramatic impairment of skin homoeostasis underscores the centrality of the EGFR-ligand system in the whole skin immune system. So far, no mechanism-based approaches are available to specifically counteract the adverse effects of anti-EGFR drugs or any other class of tyrosine kinase inhibitors. Only the knowledge of the cellular and molecular events underlying these adverse effects in humans, combined with in vitro/in vivo models able to mimic these toxic responses, may guide the development of mechanism-based treatment or prevention strategies.

Effects of a second-generation human anti-ErbB2 ImmunoRNase on trastuzumab-resistant tumors and cardiac cells

The inhibition of ErbB2 by the use of human antibodies can be a valuable strategy for the treatment of breast and gastric cancer. Trastuzumab, a humanized anti-ErbB2 antibody in clinical use, is effective but can engender resistance as well as cardiotoxicity. ImmunoRNases, made up of a human anti-ErbB2 scFv and human pancreatic ribonucleases (HP-RNases), have been engineered to overcome the limits of other immunotoxins, such as immunogenicity and nonspecific toxicity. Here, we report that a novel anti-ErbB2 immunoRNase, called Erb-HPDDADD-RNase, obtained by fusing Erbicin, a human ErbB2-directed scFv, with an HP-RNase variant that resists the cytosolic inhibitor protein, binds with high affinity to a panel of ErbB2-positive gastric tumor cells and inhibits their growth more than does the parental immunoRNase, which is not resistant to the inhibitor. Moreover, Erb-HP-DDADD-RNase is endowed with antiproliferative activity for trastuzumab-resistant cancer cells both in vitro and in vivo that is more potent than that of the parental immunoRNase. Importantly, Erb-HP-DDADD-RNase does not show cardiotoxic effects in vitro on human cardiomyocytes and does not impair cardiac function in a mouse model. Thus, Erb-HP-DDADD-RNase could fulfil the therapeutic need of cancer patients ineligible for trastuzumab treatment due to primary or acquired trastuzumab resistance or to cardiac dysfunction.

Effects of a human compact anti-ErbB2 antibody on gastric cancer

BACKGROUND

Gastric cancer represents one of the most common causes of cancer deaths worldwide. Overexpression of ErbB2, a tyrosine kinase receptor involved in the pathogenesis of several human cancer types, has been reported also in gastric cancer. Thus, the inhibition of ErbB2 signal transduction pathways by the use of human antibodies could be a valuable strategy for the therapy of this type of cancer.

METHODS

We tested for the first time the antitumor effects on gastric cancer cells of Erb-hcAb, a novel fully human compact antibody, prepared in our laboratory, which targets a different epitope of ErbB2 with respect to trastuzumab, the only anti-ErbB2 antibody currently in clinical use for both breast and gastric cancer therapy.

RESULTS

Herein we demonstrate that the in vitro and in vivo growth of gastric cancer cells is efficiently inhibited by Erb-hcAb, which shows antitumor effects on the NCI-N87 cell line more potent than those observed for trastuzumab.

CONCLUSIONS

Erb-hcAb could be a promising candidate in the immunotherapy of gastric cancer as it combines the antiproliferative effect associated with the inhibition of ErbB2 signaling on tumor target cells with the ability to induce antibody-dependent cellular cytotoxicity.