Recommendations for genetic testing to reduce the incidence of anthracycline-induced cardiotoxicity

The Role of Pharmacogenomics in Rare Diseases

Rare diseases have become an increasingly important public health priority due to their collective prevalence and often life-threatening nature. Incentive programs, such as the Orphan Drug Act have been introduced to increase the development of rare disease therapeutics. While the approval of these therapeutics requires supportive data from stringent pre-market studies, these data lack the ability to describe the causes of treatment response heterogeneity, leading to medications often being more harmful or less effective than predicted. If a Goal Line were to be used to describe the multifactorial continuum of phenotypic variations occurring in response to a medication, the 'Goal Posts', or the two defining points of this continuum, would be (1) Super-Response, or an extraordinary therapeutic effect; and (2) Serious Harm. Investigation of the pharmacogenomics behind these two extreme phenotypes can potentially lead to the development of new therapeutics, help inform rational use criteria in drug policy, and improve the understanding of underlying disease pathophysiology. In the context of rare diseases where cohort sizes are smaller than ideal, 'small data' and 'big data' approaches to data collection and analysis should be combined to produce the most robust results. This paper presents the importance of studying drug response in parallel to other research initiatives in rare diseases, as well as the need for international collaboration in the area of rare disease pharmacogenomics.

Novel molecular mechanisms of doxorubicin cardiotoxicity: latest leading-edge advances and clinical implications

Doxorubicin (Dox) is among the most widely used cancer chemotherapeutic drugs. The clinical use of Dox is, however, limited due to its cardiotoxicity. Studies over the past several decades have suggested various mechanisms of Dox-induced cardiotoxicity (DIC). Among them are oxidative stress, topoisomerase inhibition, and mitochondrial damage. Several novel molecular targets and signaling pathways underlying DIC have emerged over the past few years. The most notable advances include discovery of ferroptosis as a major form of cell death in Dox cytotoxicity, and elucidation of the involvement of cardiogenetics and regulatory RNAs as well as multiple other targets in DIC. In this review, we discuss these advances, focusing on latest cutting-edge research discoveries from mechanistic studies reported in influential journals rather than surveying all research studies available in the literature.

Heartbreaker: Detection and prevention of cardiotoxicity in hematological malignancies

Cancer survivors are at significant risk of cardiovascular (CV) morbidity and mortality; patients with hematologic malignancies have a higher rate of death due to heart failure compared to all other cancer subtypes. The majority of conventional hematologic cancer treatments is associated with increased risk of acute and long-term CV toxicity. The incidence of cancer therapy induced CV toxicity depends on the combination of patient characteristics and on the type, dose, and duration of the therapy. Early diagnosis of CV toxicity, appropriate referral, more specific cardiac monitoring follow-up and timely interventions in target patients can decrease the risk of CV adverse events, the interruption of oncological therapy, and improve the patient's prognosis. Herein, we summarize the CV effects of conventional treatments used in hematologic malignancies with a focus on definitions and incidence of the most common CV toxicities, guideline recommended early detection approaches, and preventive strategies before and during cancer treatments.

Anthracyclines induce cardiotoxicity through a shared gene expression response signature

TOP2 inhibitors (TOP2i) are effective drugs for breast cancer treatment. However, they can cause cardiotoxicity in some women. The most widely used TOP2i include anthracyclines (AC) Doxorubicin (DOX), Daunorubicin (DNR), Epirubicin (EPI), and the anthraquinone Mitoxantrone (MTX). It is unclear whether women would experience the same adverse effects from all drugs in this class, or if specific drugs would be preferable for certain individuals based on their cardiotoxicity risk profile. To investigate this, we studied the effects of treatment of DOX, DNR, EPI, MTX, and an unrelated monoclonal antibody Trastuzumab (TRZ) on iPSC-derived cardiomyocytes (iPSC-CMs) from six healthy females. All TOP2i induce cell death at concentrations observed in cancer patient serum, while TRZ does not. A sub-lethal dose of all TOP2i induces limited cellular stress but affects calcium handling, a function critical for cardiomyocyte contraction. TOP2i induce thousands of gene expression changes over time, giving rise to four distinct gene expression response signatures, denoted as TOP2i early-acute, early-sustained, and late response genes, and non-response genes. There is no drug- or AC-specific signature. TOP2i early response genes are enriched in chromatin regulators, which mediate AC sensitivity across breast cancer patients. However, there is increased transcriptional variability between individuals following AC treatments. To investigate potential genetic effects on response variability, we first identified a reported set of expression quantitative trait loci (eQTLs) uncovered following DOX treatment in iPSC-CMs. Indeed, DOX response eQTLs are enriched in genes that respond to all TOP2i. Next, we identified 38 genes in loci associated with AC toxicity by GWAS or TWAS. Two thirds of the genes that respond to at least one TOP2i, respond to all ACs with the same direction of effect. Our data demonstrate that TOP2i induce thousands of shared gene expression changes in cardiomyocytes, including genes near SNPs associated with inter-individual variation in response to DOX treatment and AC-induced cardiotoxicity.

Association between genetic variants of transmembrane transporters and susceptibility to anthracycline-induced cardiotoxicity: Current understanding and existing evidence

Anthracyclines remain the cornerstone of numerous chemotherapeutic protocols, with beneficial effects against haematological malignancies and solid tumours. Unfortunately, the clinical usefulness of anthracyclines is compromised by the development of cardiotoxic side effects, leading to dose limitations or treatment discontinuation. There is no absolute linear correlation between the incidence of cardiotoxicity and the threshold dose, suggesting that genetic factors may modify the association between anthracyclines and cardiotoxicity risk. And the majority of single nucleotide polymorphisms (SNPs) associated with anthracycline pharmacogenomics were identified in the ATP-binding cassette (ABC) and solute carrier (SLC) transporters, generating increasing interest in the pharmacogenetic implications of their genetic variations for anthracycline-induced cardiotoxicity (AIC). This review focuses on the influence of SLC and ABC polymorphisms on AIC and highlights the prospects and clinical significance of pharmacogenetics for individualised preventive approaches.

iPSCs as a groundbreaking tool for the study of adverse drug reactions: A new avenue for personalized therapy

Induced pluripotent stem cells (iPSCs), obtained by reprogramming different somatic cell types, represent a promising tool for the study of drug toxicities, especially in the context of personalized medicine. Indeed, these cells retain the same genetic heritage of the donor, allowing the development of personalized models. In addition, they represent a useful tool for the study of adverse drug reactions (ADRs) in special populations, such as pediatric patients, which are often poorly represented in clinical trials due to ethical issues. Particularly, iPSCs can be differentiated into any tissue of the human body, following several protocols which use different stimuli to induce specific differentiation processes. Differentiated cells also maintain the genetic heritage of the donor, and therefore are suitable for personalized pharmacological studies; moreover, iPSC-derived differentiated cells are a valuable tool for the investigation of the mechanisms underlying the physiological differentiation processes. iPSCs-derived organoids represent another important tool for the study of ADRs. Precisely, organoids are in vitro 3D models which better represent the native organ, both from a structural and a functional point of view. Moreover, in the same way as iPSC-derived 2D models, iPSC-derived organoids are appropriate personalized models since they retain the genetic heritage of the donor. In comparison to other in vitro models, iPSC-derived organoids present advantages in terms of versatility, patient-specificity, and ethical issues. This review aims to provide an updated report of the employment of iPSCs, and 2D and 3D models derived from these, for the study of ADRs. This article is categorized under: Cancer > Stem Cells and Development.

The Role of RARG rs2229774, SLC28A3 rs7853758, and UGT1A6*4 rs17863783 Single-nucleotide Polymorphisms in the Doxorubicin-induced Cardiotoxicity in Solid Childhood Tumors

BACKGROUND

The objective of our study was to determine the role of retinoic acid receptor gamma (RARG) rs2229774, SLC28A3 rs7853758, and UGT1A6*4 rs17863783 single-nucleotide polymorphisms in identifying the risk of doxorubicin-induced cardiotoxicity in pediatric solid tumors.

METHODS

A total of 60 pediatric patients who had completed their treatment at least 2 years ago and 50 healthy children matched for age and sex were included in the study. All patients were evaluated for cardiotoxicity by echocardiography. The blood samples were analyzed for RARG rs2229774, SLC28A3 rs7853758, and UGT1A6*4 rs17863783 polymorphisms. Demographic characteristics, echocardiographic parameters, and genetic results of both groups were evaluated.

RESULTS

In our study, the RARG rs2229774 AA genotype was associated with cardiotoxicity ( P =0.017). The SLC28A3 rs7853758 AA+GA genotype was detected more frequently in patients who did not develop cardiotoxicity ( P <0.023). Furthermore, the frequency of the SLC28A3 rs7853758 A allele was significantly lower in the cardiotoxicity group ( P <0.025).

CONCLUSIONS

This is the first study in the Turkish population to investigate the correlation between the cardiotoxicity risk and 3 marker genes, which are recommended in the pharmacogenetic guideline for risk assessment in pediatric doxorubicin patients. The gene polymorphism that we investigated in this study was useful for the early prediction of cardiotoxicity risk.

Psychological Alterations in Youths with Type I Diabetes: Associations with Salivary Cortisol Concentration

Background and Objectives: Type 1 diabetes mellitus (T1DM) is one of the most common chronic diseases in children and adolescents, and is associated with stress and other psychological alterations. This study aims to assess psychological and sleep disorders and health-related quality of life in young people with T1DM and to determine the relationship between these parameters and levels of salivary cortisol, a hormone widely associated with stress and several psychological symptoms. Materials and Methods: In our cross-sectional study performed in 60 Moroccan children and adolescents with T1DM, detailed psychological evaluations were performed to assess symptoms of anxiety, attention-deficit hyperactivity disorder (ADHD), sleep quality and diabetes-specific quality of life (using the RCMAS-2, ADHD rating scale, Pittsburgh scale and the DQoL scale, respectively), and cortisol concentration was measured from saliva samples taken mid-morning. Results: A total of 60 children and adolescents with T1DM were recruited. The mean age was 11.05 ± 0.35 (6-17). The mean salivary cortisol level in ng/mL was 4.7 ± 0.49 (0.7-20.2) and was significantly associated with an anxiety RCMAS2 score for the Worry subdomain and DQoL subdomain "Anxiety". Linear regression analysis showed that salivary cortisol was significantly higher in girls compared to boys (p = 0.004) (beta coefficient: 3.384 CI95%: 1.137-5.630) and with Hb1AC level as a continuous variable (p = 0.0001) (beta coefficient: 1.135 CI95%: 0.509-1.760). The other variables included in the model were not significant (p > 0.05). There was an association between salivary cortisol concentration with anxiety RCMAS2 score for Worry subdomain and QoL sub-domain "Anxiety". Still, a significant (p = 0.018) association emerged for anxiety RCMAS2 score Worry subdomain and QoL anxiety subdomain (p = 0.044). Conclusions: Children and adolescents with T1DM experienced significantly elevated symptoms of anxiety and sleep disturbances, particularly in girls, and frequent symptoms of ADHD, particularly in boys. Salivary cortisol concentration collected in the morning is associated with anxiety burden but not with other psychological alterations. Further studies are needed to clarify the associations between salivary cortisol concentration and anxiety in type 1 diabetes in order to propose the hormone as a biomarker for interventions aimed to reduce anxiety levels in these patients.

Systematic Critical Review of Genetic Factors Associated with Cisplatin-induced Ototoxicity: Canadian Pharmacogenomics Network for Drug Safety 2022 Update

BACKGROUND

Cisplatin is commonly used to treat solid tumors; however, its use can be complicated by drug-induced hearing loss (ie, ototoxicity). The presence of certain genetic variants has been associated with the development/occurrence of cisplatin-induced ototoxicity, suggesting that genetic factors may be able to predict patients who are more likely to develop ototoxicity. The authors aimed to review genetic associations with cisplatin-induced ototoxicity and discuss their clinical relevance.

METHODS

An updated systematic review was conducted on behalf of the Canadian Pharmacogenomics Network for Drug Safety, based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses 2020 statement. Pharmacogenomic studies that reported associations between genetic variation and cisplatin-induced ototoxicity were included. The evidence on genetic associations was summarized and evaluated, and knowledge gaps that can be used to inform future pharmacogenomic studies identified.

RESULTS

Overall, 40 evaluated reports, considering 47 independent patient populations, captured associations involving 24 genes. Considering GRADE criteria, genetic variants in 2 genes were strongly (ie, odds ratios ≥3) and consistently (ie, replication in ≥3 independent populations) predictive of cisplatin-induced ototoxicity. Specifically, an ACYP2 variant has been associated with ototoxicity in both children and adults, whereas TPMT variants are relevant in children. Encouraging evidence for associations involving several other genes also exists; however, further research is necessary to determine potential clinical relevance.

CONCLUSIONS

Genetic variation in ACYP2 and TPMT may be helpful in predicting patients at the highest risk of developing cisplatin-induced ototoxicity. Further research (including replication studies considering diverse pediatric and adult patient populations) is required to determine whether genetic variation in additional genes may help further identify patients most at risk.

Importance of familial predisposition to heart failure to the risk of anthracycline-related cardiotoxicity: A nationwide study

BACKGROUND

Anthracycline-based chemotherapy has improved the prognosis of various malignancies, but increases the long-term risk of heart failure (HF). Identification of patients at risk prior to treatment initiation is warranted. Therefore, the aim of this study was to evaluate if a familial predisposition to HF increases the risk of anthracycline related HF.

METHODS

Using nationwide Danish registries, all patients treated with anthracycline from 2004 to 16 were identified. The primary outcome was long-term HF risk. First-degree relatives were identified in the Danish Family Registry and exposure was defined as a first-degree biological relative with prior HF. Risk of HF was evaluated in a cumulative incidence function and the association in a multivariable Cox regression model.

RESULTS

A total of 11,651 patients (median age 49.1 years (IQR: 43.6-53.7), 12.2% male) were included after exclusion of 46 with preanthracycline HF. Median follow-up was 3.8 years (IQR 1.9-6.4). In the group with a first-degree relative with HF (n = 1,608) 35 patients (2.2%) were diagnosed with HF vs 133 (1.3%) in the group without a first-degree relative with HF (n = 10,043), corresponding to incidence rates per 1,000 patient-years of 5.2 (CI:3.8-7.3) vs 3.0 (CI:2.5-3.5). The cumulative incidence of HF after 10 years was higher in the first-degree relative group (3.2% vs 2.0%, P = .004); adjusted hazard ratio 1.53 (CI:1.05-2.23, P = .03).

CONCLUSION

In this nationwide register-based study having a first-degree relative with HF was associated with increased risk of anthracycline related HF, suggesting that attention towards family predisposition may be warranted when estimating the risk of anthracycline related cardiotoxicity.

Identification of novel hypermethylated or hypomethylated CpG sites and genes associated with anthracycline-induced cardiomyopathy

Anthracycline-induced cardiomyopathy is a leading cause of late morbidity in childhood cancer survivors. Aberrant DNA methylation plays a role in de novo cardiovascular disease. Epigenetic processes could play a role in anthracycline-induced cardiomyopathy but remain unstudied. We sought to examine if genome-wide differential methylation at 'CpG' sites in peripheral blood DNA is associated with anthracycline-induced cardiomyopathy. This report used participants from a matched case-control study; 52 non-Hispanic White, anthracycline-exposed childhood cancer survivors with cardiomyopathy were matched 1:1 with 52 survivors with no cardiomyopathy. Paired ChAMP (Chip Analysis Methylation Pipeline) with integrated reference-based deconvolution of adult peripheral blood DNA methylation was used to analyze data from Illumina HumanMethylation EPIC BeadChip arrays. An epigenome-wide association study (EWAS) was performed, and the model was adjusted for GrimAge, sex, interaction terms of age at enrollment, chest radiation, age at diagnosis squared, and cardiovascular risk factors (CVRFs: diabetes, hypertension, dyslipidemia). Prioritized genes were functionally validated by gene knockout in human induced pluripotent stem cell cardiomyocytes (hiPSC-CMs) using CRISPR/Cas9 technology. DNA-methylation EPIC array analyses identified 32 differentially methylated probes (DMP: 15 hyper-methylated and 17 hypo-methylated probes) that overlap with 23 genes and 9 intergenic regions. Three hundred and fifty-four differential methylated regions (DMRs) were also identified. Several of these genes are associated with cardiac dysfunction. Knockout of genes EXO6CB, FCHSD2, NIPAL2, and SYNPO2 in hiPSC-CMs increased sensitivity to doxorubicin. In addition, EWAS analysis identified hypo-methylation of probe 'cg15939386' in gene RORA to be significantly associated with anthracycline-induced cardiomyopathy. In this genome-wide DNA methylation profile study, we observed significant differences in DNA methylation at the CpG level between anthracycline-exposed childhood cancer survivors with and without cardiomyopathy, implicating differential DNA methylation of certain genes could play a role in pathogenesis of anthracycline-induced cardiomyopathy.

RBL2 Regulates Cardiac Sensitivity to Anthracycline Chemotherapy

Background

Anthracycline chemotherapies cause heart failure in a subset of cancer patients. We previously reported that the anthracycline doxorubicin (DOX) induces cardiotoxicity through the activation of cyclin-dependent kinase 2 (CDK2).

Objectives

The aim of this study was to determine whether retinoblastoma-like 2 (RBL2/p130), an emerging CDK2 inhibitor, regulates anthracycline sensitivity in the heart.

Methods

Rbl2-/- mice and Rbl2+/+ littermates received DOX (5 mg/kg/wk for 4 weeks intraperitoneally, 20 mg/kg cumulative). Heart function was monitored with echocardiography. The association of RBL2 genetic variants with anthracycline cardiomyopathy was evaluated in the SJLIFE (St. Jude Lifetime Cohort Study) and CPNDS (Canadian Pharmacogenomics Network for Drug Safety) studies.

Results

The loss of endogenous Rbl2 increased basal CDK2 activity in the mouse heart. Mice lacking Rbl2 were more sensitive to DOX-induced cardiotoxicity, as evidenced by rapid deterioration of heart function and loss of heart mass. The disruption of Rbl2 exacerbated DOX-induced mitochondrial damage and cardiomyocyte apoptosis. Mechanistically, Rbl2 deficiency enhanced CDK2-dependent activation of forkhead box O1 (FOXO1), leading to up-regulation of the proapoptotic protein Bim. The inhibition of CDK2 desensitized Rbl2-depleted cardiomyocytes to DOX. In wild-type cardiomyocytes, DOX exposure induced Rbl2 expression in a FOXO1-dependent manner. Importantly, the rs17800727 G allele of the human RBL2 gene was associated with reduced anthracycline cardiotoxicity in childhood cancer survivors.

Conclusions

Rbl2 is an endogenous CDK2 inhibitor in the heart and represses FOXO1-mediated proapoptotic gene expression. The loss of Rbl2 increases sensitivity to DOX-induced cardiotoxicity. Our findings suggest that RBL2 could be used as a biomarker to predict the risk of cardiotoxicity before the initiation of anthracycline-based chemotherapy.

Prognostic Factors for Cardiotoxicity among Children with Cancer: Definition, Causes, and Diagnosis with Omics Technologies

Improvements in the treatment of childhood cancer have considerably enhanced survival rates over the last decades to over 80% as of today. However, this great achievement has been accompanied by the occurrence of several early and long-term treatment-related complications major of which is cardiotoxicity. This article reviews the contemporary definition of cardiotoxicity, older and newer chemotherapeutic agents that are mainly involved in cardiotoxicity, routine process diagnoses, and methods using omics technology for early and preventive diagnosis. Chemotherapeutic agents and radiation therapies have been implicated as a cause of cardiotoxicity. In response, the area of cardio-oncology has developed into a crucial element of oncologic patient care, committed to the early diagnosis and treatment of adverse cardiac events. However, routine diagnosis and the monitoring of cardiotoxicity rely on electrocardiography and echocardiography. For the early detection of cardiotoxicity, in recent years, major studies have been conducted using biomarkers such as troponin, N-terminal pro b-natriuretic peptide, etc. Despite the refinements in diagnostics, severe limitations still exist due to the increase in the above-mentioned biomarkers only after significant cardiac damage has occurred. Lately, the research has expanded by introducing new technologies and finding new markers using the omics approach. These new markers could be used not only for early detection but also for the early prevention of cardiotoxicity. Omics science, which includes genomics, transcriptomics, proteomics, and metabolomics, offers new opportunities for biomarker discovery in cardiotoxicity and may provide an understanding of the mechanisms of cardiotoxicity beyond traditional technologies.

The Impact of Polymorphisms in ATP-Binding Cassette Transporter Genes on Anthracycline-Induced Early Cardiotoxicity in Patients with Breast Cancer

BACKGROUND

Cardiac side effects associated with anthracycline-based treatment may seriously compromise the prognosis of patients with breast cancer (BC). Evidence shows that genes that operate in drug metabolism can influence the risk of anthracycline-induced cardiotoxicity (AIC). ATP-binding cassette (ABC) transporters could serve as one of the potential biomarkers for AIC risk stratification. We aimed to determine the link between single-nucleotide polymorphisms (SNPs) in several ABC genes (ABCB1 rs1045642, ABCC1 rs4148350, ABCC1 rs3743527) and cardiotoxicity.

METHODS

The study included 71 patients with BC, who were treated with doxorubicin-based chemotherapy. Two-dimensional echocardiography and speckle-tracking echocardiography were performed. AIC was defined as a new decrease of 10 percentage points in the left ventricular ejection fraction (LVEF). SNPs in ABCB1 and ABCC1 genes were evaluated using real-time PCR.

RESULTS

After a cumulative dose of 236.70 mg/m² of doxorubicin, 28.2% patients met the criteria of AIC. Patients who developed AIC had a larger impairment in left ventricular systolic function compared to those who did not develop AIC (LVEF: 50.20 ± 2.38% vs. 55.41 ± 1.13%, p < 0.001; global longitudinal strain: -17.03 ± 0.52% vs. -18.40 ± 0.88%, p < 0.001). The ABCC1 rs4148350 TG genotype was associated with higher rates of cardiotoxicity (TG vs. GG OR = 8.000, 95% CI = 1.405-45.547, p = 0.019).

CONCLUSIONS

The study showed that ABCC1 rs4148350 is associated with AIC and could be a potential biomarker to assess the risk of treatment side effects in patients with BC.

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.

Prognostic Impact of Global Longitudinal Strain and NT-proBNP on Early Development of Cardiotoxicity in Breast Cancer Patients Treated with Anthracycline-Based Chemotherapy

Background. The most important anthracycline side effect is cardiotoxicity, resulting in congestive heart failure (HF). Early detection of cardiac dysfunction and appropriate treatment can improve outcomes and reduce the progression of HF. The aim of our study was to evaluate changes in clinical data, echocardiographic parameters, and NT-proBNP, as well as their associations with early anthracycline-induced cardiotoxicity (AIC) in patients treated with anthracycline-based chemotherapy. Methods and Materials. Patients with breast cancer were prospectively assessed with echocardiography, as well as NT-proBNP testing at baseline, (T0), after two cycles (T1) and four cycles (T2) of chemotherapy. AIC was defined as a new decrease in the LVEF of 10 percentage points, to a value below the lower limit of normal. Results. We evaluated 85 patients aged 54.5 ± 9.3 years. After a cumulative dose of 237.9 mg/m² of doxorubicin, 22 patients (25.9%) met the criteria of AIC after chemotherapy. Patients who subsequently progressed to cardiotoxicity had demonstrated a significantly larger impairment in LV systolic function compared to those who did not develop cardiotoxicity (LVEF: 54.0 ± 1.6% vs. 57.1 ± 1.4% at T1, p < 0.001, and 49.9 ± 2.1% vs. 55.8 ± 1.6% at T2, p < 0.001; GLS: -17.8 ± 0.4% vs. -19.3 ± 0.9% at T1, p < 0.001, and -16.5 ± 11.1% vs. -18.5 ± 0.9% at T2, p < 0.001, respectively). The levels of NT-proBNP increased significantly from 94.8 ± 43.8 ng/L to 154.1 ± 75.6 ng/L, p < 0.001. A relative decrease in GLS ≤ -18.0% (sensitivity: 72.73%; specificity: 92.06%; AUC, 0.94; p < 0.001) and a relative increase in NT-proBNP > 125 ng/L (sensitivity: 90.0%; specificity: 56.9%; AUC, 0.78; p < 0.001) from baseline to T1 predicted subsequent LV cardiotoxicity at T2. Conclusions. Decrease in GLS and elevation in NT-proBNP were significantly associated with AIC, and these could potentially be used to predict subsequent declines in LVEF with anthracycline-based chemotherapy.

Evolving field of cardio-oncology

Therapy development for cancer and cardiovascular disease (CVD) to prolong lifespan makes the relationship between these two conditions more complex. Drug interactions in cardiology and oncology are associated with metabolism and drug transportation. Advances in biomarkers and imaging provide novel methods for detecting cardiotoxicity, including cardiac injury and inflammation. The new concept of CVD-related cancer risk is leading to a new direction of progression termed "reverse cardio-oncology."

Systematic review and updated recommendations for cardiomyopathy surveillance for survivors of childhood, adolescent, and young adult cancer from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Survivors of childhood, adolescent, and young adult cancer, previously treated with anthracycline chemotherapy (including mitoxantrone) or radiotherapy in which the heart was exposed, are at increased risk of cardiomyopathy. Symptomatic cardiomyopathy is typically preceded by a series of gradually progressive, asymptomatic changes in structure and function of the heart that can be ameliorated with treatment, prompting specialist organisations to endorse guidelines on cardiac surveillance in at-risk survivors of cancer. In 2015, the International Late Effects of Childhood Cancer Guideline Harmonization Group compiled these guidelines into a uniform set of recommendations applicable to a broad spectrum of clinical environments with varying resource availabilities. Since then, additional studies have provided insight into dose thresholds associated with a risk of asymptomatic and symptomatic cardiomyopathy, have characterised risk over time, and have established the cost-effectiveness of different surveillance strategies. This systematic Review and guideline provides updated recommendations based on the evidence published up to September, 2020.

Pharmacogenetic Aspects of Drug Metabolizing Enzymes and Transporters in Pediatric Medicine: Study Progress, Clinical Practice and Future Perspectives

As the activity of certain drug metabolizing enzymes or transporter proteins can vary with age, the effect of ontogenetic and genetic variation on the activity of these enzymes is critical for the accurate prediction of treatment outcomes and toxicity in children. This makes pharmacogenetic research in pediatrics particularly important and urgently needed, but also challenging. This review summarizes pharmacogenetic studies on the effects of genetic polymorphisms on pharmacokinetic parameters and clinical outcomes in pediatric populations for certain drugs, which are commonly prescribed by clinicians across multiple therapeutic areas in a general hospital, organized from those with the most to the least pediatric evidence among each drug category. We also further discuss the research status of the gene-guided dosing regimens and clinical implementation of pediatric pharmacogenetics. More and more drug-gene interactions are demonstrated to have clinical validity for children, and pharmacogenomics in pediatrics have shown evidence-based benefits to enhance the efficacy and precision of existing drug dosing regimens in several therapeutic areas. However, the most important limitation to the implementation is the lack of high-quality, rigorous pediatric prospective clinical studies, so adequately powered interventional clinical trials that support incorporation of pharmacogenetics into the care of children are still needed.

PAnno: A pharmacogenomics annotation tool for clinical genomic testing

Introduction: Next-generation sequencing (NGS) technologies have been widely used in clinical genomic testing for drug response phenotypes. However, the inherent limitations of short reads make accurate inference of diplotypes still challenging, which may reduce the effectiveness of genotype-guided drug therapy. Methods: An automated Pharmacogenomics Annotation tool (PAnno) was implemented, which reports prescribing recommendations and phenotypes by parsing the germline variant call format (VCF) file from NGS and the population to which the individual belongs. Results: A ranking model dedicated to inferring diplotypes, developed based on the allele (haplotype) definition and population allele frequency, was introduced in PAnno. The predictive performance was validated in comparison with four similar tools using the consensus diplotype data of the Genetic Testing Reference Materials Coordination Program (GeT-RM) as ground truth. An annotation method was proposed to summarize prescribing recommendations and classify drugs into avoid use, use with caution, and routine use, following the recommendations of the Clinical Pharmacogenetics Implementation Consortium (CPIC), etc. It further predicts phenotypes of specific drugs in terms of toxicity, dosage, efficacy, and metabolism by integrating the high-confidence clinical annotations in the Pharmacogenomics Knowledgebase (PharmGKB). PAnno is available at https://github.com/PreMedKB/PAnno. Discussion: PAnno provides an end-to-end clinical pharmacogenomics decision support solution by resolving, annotating, and reporting germline variants.

Pharmacogenetics in treatment of anthracycline-induced cardiotoxicity in women without prior cardiovascular diseases

Aim. To evaluate the role of polymorphisms in adrenoceptor beta 1 (ADRB1) (Arg389Gly, rs1801253) and angiotensin-converting enzyme (ACE) (I/D, rs4343) genes in assessing the effectiveness of β-blocker (carvedilol) and ACE inhibitor (enalapril) therapy in women with anthracycline-induced cardiotoxicity (AIC) without prior cardiovascular diseases (CVD) during 12-month follow-up.

Materials and methods. A total of 82 women (average age 45.0 (42.0; 50.0) years) with AIC and without prior CVD were included in the study. Echocardiography was performed and serum levels of NT-proBNP were determined at baseline and at 12 months after the enrollment. Gene polymorphisms in ADRB1 and ACE genes were evaluated by polymerase chain reaction at baseline.

Results. Carriers of the G/G genotype in the ADRB1 gene and G/G genotype in the ACE (I/D, rs4343) gene showed a significant increase in left ventricular ejection fraction (LVEF), a decrease in the size of the left ventricle (LV) and left atrium (LA), and a fall in the NT-proBNP level. Carriers of other genotypes had further progression of AIC which was manifested through a decrease in LVEF and an increase in the size of LV and LA.

Conclusion. Evaluation of gene polymorphisms in ADRB1 (Arg389Gly, rs1801253) and ACE (I/D, rs4343) genes may be recommended before treatment initiation for AIC in women without prior CVD to determine who will benefit from carvedilol and enalapril therapy, as well as to identify a priority group of patients for personalized intensification and optimization of treatment for decreasing development of adverse cardiovascular events.

Cardiotoxicity and pharmacogenetics of doxorubicin in black Zimbabwean breast cancer patients

AIMS

Doxorubicin-induced cardiotoxicity (DIC) is a significant cause of mortality in cancer care. This study was conducted to establish the frequency of DIC in Zimbabwean breast cancer patients on doxorubicin and to test the DIC predictive power of genetic biomarkers.

METHODS

A cohort of 50 Zimbabwean breast cancer patients treated with doxorubicin were followed up for 12 months with serial echocardiography and genotyped for UGTA1A6*4, SLC28A3 and RARG. Eleven per cent of the patients experienced DIC.

RESULTS

The frequencies of SLC28A3 (rs7853758), UGT1A6*4 (rs17863783) and RARG (rs2229774) were 60.7%, 17.9% and 14.3%, respectively. No association between DIC and the three variants was observed.

CONCLUSIONS

This is the first study on the prevalence of DIC and associated genetic biomarker predictive evaluation in Zimbabwean breast cancer patients. The genetic frequencies observed in our study were different to those reported in other populations. A larger sample size with a longer follow-up time will be necessary in future studies.

Cardio-Oncology in Childhood: State of the Art

PURPOSE OF REVIEW

Cardio-oncology is an increasingly important field of cardiology that focuses on the detection, monitoring, and treatment of cardiovascular disease (CVD) occurring during and after oncological treatments. The survival rate for childhood cancer patients has dramatically increased thanks to new treatment protocols and cardiovascular (CV) sequelae represent the third most frequent cause of mortality in surviving patients. This study aims to provide a complete and updated review of all the main aspects of cardio-oncology in childhood and to highlight the critical issues.

RECENT FINDINGS

The problem of CV complications in childhood cancer survivors raises the need to make an early diagnosis of cardiotoxicity by the new imaging and laboratory techniques in order to intervene promptly and to implement pharmacological strategies and lifestyle changes to reduce or even to prevent cardiac injury. Furthermore, a stratification of CV risk, also including new predisposing factors such as the presence of some genetic mutations, is of paramount importance before undertaking oncological treatments. Besides, a systematic and personalized planning of long-term follow-up is fundamental to ensure a transition from pediatric to adult hospital and to avoid missed or late diagnosis of cardiomyopathy. We reviewed the main risk factors for cardiotoxicity in children, both traditional and emerging ones: the mechanisms of toxicity of both old and new antineoplastic therapies, the techniques for detecting cardiac damage, and the current evidence regarding pharmacological cardioprotection. At the end, we focused our attention on the existing guidelines and strategies about the long-term follow-up of childhood cancer survivors.

A non-coding GWAS variant impacts anthracycline-induced cardiotoxic phenotypes in human iPSC-derived cardiomyocytes

Anthracyclines, widely used to treat breast cancer, have the potential for cardiotoxicity. We have previously identified and validated a germline single nucleotide polymorphism, rs28714259, associated with an increased risk of anthracycline-induced heart failure. We now provide insights into the mechanism by which rs28714259 might confer increased risk of cardiac damage. Using hiPSC-derived cardiomyocyte cell lines with either intrinsic polymorphism or CRISPR-Cas9-mediated deletion of rs28714259 locus, we demonstrate that glucocorticoid receptor signaling activated by dexamethasone pretreatment prior to doxorubicin exposure preserves cardiomyocyte viability and contractility in cardiomyocytes containing the major allele. Homozygous loss of the rs28714259 major allele diminishes dexamethasone's protective effect. We further demonstrate that the risk allele of rs28714259 disrupts glucocorticoid receptor and rs28714259 binding affinity. Finally, we highlight the activation of genes and pathways involved in cardiac hypertrophy signaling that are blocked by the risk allele, suggesting a decreased adaptive survival response to doxorubicin-related stress.

Pharmacogenetics of Drug Metabolism: The Role of Gene Polymorphism in the Regulation of Doxorubicin Safety and Efficacy

Simple Summary

The effectiveness and safety of the anti-cancer agent doxorubicin (anthracycline group medicine) depend on the metabolism and retention of the drug in the human organism. Polymorphism of cytochrome p450 (CYP)-encoding genes and detoxifying enzymes such as CYP3A4 and CYP2D6 were found responsible for variations in the doxorubicin metabolism. Transmembrane transporters such as p-glycoproteins were reported to be involved in cancer tissue retention of doxorubicin. ATP-binding cassette (ABC) family members, including ABCB1 transporters (also known as Multi-Drug Resistance 1 (MDR1)) proteins, were determined to pump out doxorubicin from breast cancer cells, therefore reducing the drug effectiveness. This study critically discusses the latest data about the role of CYP3A4, CYP2D6, and ABCB1 gene polymorphism in the regulation of doxorubicin’s effects in breast cancer patients. The assessment of genetic differences in the expression of doxorubicin metabolizing and transporting enzymes should be explored for the development of personalized medical treatment of breast cancer patients.

Abstract

Breast cancer (BC) is the prevailing malignancy and major cause of cancer-related death in females. Doxorubicin is a part of BC neoadjuvant and adjuvant chemotherapy regimens. The administration of anthracycline derivates, such as doxorubicin, may cause several side effects, including hematological disfunction, gastrointestinal toxicity, hepatotoxicity, nephrotoxicity, and cardiotoxicity. Cardiotoxicity is a major adverse reaction to anthracyclines, and it may vary depending on individual differences in doxorubicin pharmacokinetics. Determination of specific polymorphisms of genes that can alter doxorubicin metabolism was shown to reduce the risk of adverse reactions and improve the safety and efficacy of doxorubicin. Genes which encode cytochrome P450 enzymes (CYP3A4 and CYP2D6), p-glycoproteins (ATP-binding cassette (ABC) family members such as Multi-Drug Resistance 1 (MDR1) protein), and other detoxifying enzymes were shown to control the metabolism and pharmacokinetics of doxorubicin. The effectiveness of doxorubicin is defined by the polymorphism of cytochrome p450 and p-glycoprotein-encoding genes. This study critically discusses the latest data about the role of gene polymorphisms in the regulation of doxorubicin’s anti-BC effects. The correlation of genetic differences with the efficacy and safety of doxorubicin may provide insights for the development of personalized medical treatment for BC patients.

All-trans retinoic acid (ATRA) regulates key genes in the RARG-TOP2B pathway and reduces anthracycline-induced cardiotoxicity

The effectiveness of anthracycline chemotherapeutics (e.g., doxorubicin) is limited by anthracycline-induced cardiotoxicity (ACT). A nonsynonymous variant (S427L) in the retinoic acid receptor-γ (RARG) gene has been associated with ACT. This variant causes reduced RARG activity, which is hypothesized to lead to increased susceptibility to ACT through reduced activation of the retinoic acid pathway. This study explored the effects of activating the retinoic acid pathway using a RAR-agonist, all-trans retinoic acid (ATRA), in human cardiomyocytes and mice treated with doxorubicin. In human cardiomyocytes, ATRA induced the gene expression of RARs (RARG, RARB) and repressed the expression of topoisomerase II enzyme genes (TOP2A, TOP2B), which encode for the molecular targets of anthracyclines and repressed downstream ACT response genes. Importantly, ATRA enhanced cell survival of human cardiomyocytes exposed to doxorubicin. The protective effect of ATRA was also observed in a mouse model (B6C3F1/J) of ACT, in which ATRA treatment improved heart function compared to doxorubicin-only treated mice. Histological analyses of the heart also indicated that ATRA treatment reduced the pathology associated with ACT. These findings provide additional evidence for the retinoic acid pathway’s role in ACT and suggest that the RAR activator ATRA can modulate this pathway to reduce ACT.

Anthracycline-induced cardiotoxicity in women without cardiovascular diseases: molecular and genetic predictors

OBJECTIVE

To evaluate role of molecular (endothelin-1, soluble Fas-L, NT-proBNP, TNF-α, interleukin-1β,) and genetic factors (NOS3 (rs1799983), EDNRA (C + 70G, rs5335), NADPH oxidase (C242T, rs4673), p53 protein (polymorphic marker-Arg72Pro exon 4, rs1042522), NOS3 (Glu298Asp, rs1799983), Caspase 8 (CASP8, rs3834129 and rs1045485), interleukin-1β gene (Il-1β, rs1143634), TNF-α gene (rs1800629), SOD2 (rs4880), GPX1 (rs1050450) in development of anthracycline-induced cardiotoxicity (AIC) in women without cardiovascular diseases.

METHODS

A total of 176 women with breast cancer and without cardiovascular diseases who received anthracyclines were enrolled in the study. After the 12 months of chemotherapy (CT), all patients were divided into two groups: group 1 (n = 52) comprised patients with AIC, group 2 (n = 124) comprised those without it.

RESULTS

Based on ROC-analysis, levels of endothelin-1 of ≥9.0 pg/mL (AUC of 0.699), sFas-L of ≥98.3 ng/mL (AUC of 0.990), and NT-proBNP of ≥71.5 pg/mL (AUC of 0.994;) were identified as a cut-off values predicting AIC during 12 months after CT. Whereas, NT-proBNP and sFas-L were more significant predictors than endothelin-1 (p < 0.001). The development of AIC was significantly related to Arg/Arg of p53 protein gene (OR = 2.972; p = 0.001), T/T of NOS3 gene (OR = 3.059, p = 0.018), T/T of NADPH oxidase gene (OR = 2.753, p = 0.008), and C/C of GPX1 (OR = 2.345; p = 0.007).

CONCLUSION

Evaluation of polymorphisms genes of p53 (rs1042522), NOS3 (rs1799983), GPX1 (rs1050450), and NADPH oxidase (rs4673) can be recommended before CT for the risk assessment of AIC development. The serum levels of NT-proBNP and soluble Fas-L after CT may be considered as non-invasive biomarkers for prediction of AIC development during the 12 months.

A systematic review of miRNAs as biomarkers for chemotherapy-induced cardiotoxicity in breast cancer patients reveals potentially clinically informative panels as well as key challenges in miRNA research

Breast cancer patients are at a particularly high risk of cardiotoxicity from chemotherapy having a detrimental effect on quality-of-life parameters and increasing the risk of mortality. Prognostic biomarkers would allow the management of therapies to mitigate the risks of cardiotoxicity in vulnerable patients and a key potential candidate for such biomarkers are microRNAs (miRNA). miRNAs are post-transcriptional regulators of gene expression which can also be released into the circulatory system and have been associated with the progression of many chronic diseases including many types of cancer. In this review, the evidence for the potential application of miRNAs as biomarkers for chemotherapy-induced cardiotoxicity (CIC) in breast cancer patientsis evaluated and a simple meta-analysis is performed to confirm the replication status of each reported miRNA. Further selection of miRNAs is performed by reviewing the reported associations of each miRNA with other cardiovascular conditions. Based on this research, the most representative panels targeting specific chemotherapy agents and treatment regimens are suggested, that contain several informative miRNAs, including both general markers of cardiac damage as well as those for the specific cancer treatments.

Disclosing an In-Frame Deletion of the Titin Gene as the Possible Predisposing Factor of Anthracycline-Induced Cardiomyopathy: A Case Report

Anthracycline-induced cardiomyopathy has been noted as a non-neglectable issue in the field of clinical oncology. Remarkable progress has been achieved in searching for inherited susceptible genetic deficits underlying anthracycline cardiotoxicity in the past several years. In this case report, we present the preliminary results of a genetic study in a young male patient who was treated with standard dose anthracycline-based chemotherapy for his acute myeloid leukemia and attacked by acute congestive heart failure after just two courses of therapy. After a survey of 76 target genes, an in-frame deletion of the titin gene was recognized as the most possible genetic defect responsible for his cardiomyopathy caused by anthracycline. This defect proved to pass down from the patient′s mother and did not exist in seven unrelated chemotherapy-treated cancer patients without chemotherapy-induced cardiomyopathy and four other healthy volunteer DNA donors.

Current Status and Trends of Research on Anthracycline-Induced Cardiotoxicity from 2002 to 2021: A Twenty-Year Bibliometric and Visualization Analysis

Anthracyclines constitute the cornerstone of numerous chemotherapy regimens for various cancers. However, the clinical application of anthracyclines is significantly limited to their dose-dependent cardiotoxicity. A comprehensive understanding of the current status of anthracycline-induced cardiotoxicity is necessary for in-depth research and optimal clinical protocols. Bibliometric analysis is widely applied in depicting development trends and tracking frontiers of a specific field. The present study is aimed at revealing the status and trends of anthracycline-induced cardiotoxicity during the past two decades by employing bibliometric software including R-bibliometric, VOSviewer, and CiteSpace. A total of 3504 publications concerning anthracycline-induced cardiotoxicity from 2002 to 2021 were collected from the Web of Science Core Collection database. Results showed significant growth in annual yields from 90 records in 2002 to 304 papers in 2021. The United States was the most productive country with the strongest collaboration worldwide in the field. Charles University in the Czech Republic was the institution that contributed the most papers, while 7 of the top 10 productive institutions were from the United States. The United States Department of Health and Human Services and the National Institutes of Health are the two agencies that provide financial support for more than 50% of sponsored publications. The research categories of included publications mainly belong to Oncology and Cardiac Cardiovascular Systems. The Journal of Clinical Oncology had a comprehensive impact on this research field with the highest IF value and many publications. Simunek Tomas from Charles University contributed the most publications, while Lipshultz Steven E. from the State University of New York possessed the highest H-index. In addition, the future research frontiers of anthracycline-induced cardiotoxicity might include early detection, pharmacogenomics, molecular mechanism, and cardiooncology. The present bibliometric analysis may provide a valuable reference for researchers and practitioners in future research directions.

Genetic Susceptibility and Mechanisms Underlying the Pathogenesis of Anthracycline-Associated Cardiotoxicity

Anthracyclines are chemotherapeutic agents widely used to treat a variety of cancers, and these drugs have revolutionized our management of cancer patients. The dose-dependent cardiotoxicity of anthracyclines, however, remains one of the leading causes of chemotherapy treatment-associated mortality in cancer survivors. Patient threshold doses leading to anthracycline-induced cardiotoxicity (AIC) are highly variable among affected patients. This variability is largely ascribed to genetic variants in individuals' genomes. Here, we briefly discuss the prevailing mechanisms underlying the pathogenesis of AIC, and then, we review the genetic variants, mostly identified through human genetic approaches and identified in cancer survivors. The identification of all genetic susceptibilities and elucidation of underlying mechanisms of AIC can help improve upfront risk prediction assessment for potentially severe cardiotoxicity disease and provide valuable insights into the understanding of AIC pathophysiology, which can be further leveraged to develop targeted pharmacogenetic therapies for those at high risk.

The Therapeutic Potential of Carnosine as an Antidote against Drug-Induced Cardiotoxicity and Neurotoxicity: Focus on Nrf2 Pathway

Different drug classes such as antineoplastic drugs (anthracyclines, cyclophosphamide, 5-fluorouracil, taxanes, tyrosine kinase inhibitors), antiretroviral drugs, antipsychotic, and immunosuppressant drugs are known to induce cardiotoxic and neurotoxic effects. Recent studies have demonstrated that the impairment of the nuclear factor erythroid 2–related factor 2 (Nrf2) pathway is a primary event in the pathophysiology of drug-induced cardiotoxicity and neurotoxicity. The Nrf2 pathway regulates the expression of different genes whose products are involved in antioxidant and inflammatory responses and the detoxification of toxic species. Cardiotoxic drugs, such as the anthracycline doxorubicin, or neurotoxic drugs, such as paclitaxel, suppress or impair the Nrf2 pathway, whereas the rescue of this pathway counteracts both the oxidative stress and inflammation that are related to drug-induced cardiotoxicity and neurotoxicity. Therefore Nrf2 represents a novel pharmacological target to develop new antidotes in the field of clinical toxicology. Interestingly, carnosine (β-alanyl-l-histidine), an endogenous dipeptide that is characterized by strong antioxidant, anti-inflammatory, and neuroprotective properties is able to rescue/activate the Nrf2 pathway, as demonstrated by different preclinical studies and preliminary clinical evidence. Starting from these new data, in the present review, we examined the evidence on the therapeutic potential of carnosine as an endogenous antidote that is able to rescue the Nrf2 pathway and then counteract drug-induced cardiotoxicity and neurotoxicity.

Shared Genetic Risk Factors Between Cancer and Cardiovascular Diseases

Cancer and cardiovascular diseases (CVD) account for approximately 27.5 million deaths every year. While they share some common environmental risk factors, their shared genetic risk factors are not yet fully understood. The aim of the present study was to aggregate genetic risk factors associated with the comorbidity of cancer and CVDs. For this purpose, we: (1) created a catalog of genes associated with cancer and CVDs, (2) visualized retrieved data as a gene-disease network, and (3) performed a pathway enrichment analysis. We performed screening of PubMed database for literature reporting genetic risk factors in patients with both cancer and CVD. The gene-disease network was visualized using Cytoscape and the enrichment analysis was conducted using Enrichr software. We manually reviewed the 181 articles fitting the search criteria and included 13 articles in the study. Data visualization revealed a highly interconnected network containing a single subnetwork with 56 nodes and 146 edges. Genes in the network with the highest number of disease interactions were JAK2, TTN, TET2, and ATM. The pathway enrichment analysis revealed that genes included in the study were significantly enriched in DNA damage repair (DDR) pathways, such as homologous recombination. The role of DDR mechanisms in the development of CVDs has been studied in previously published research; however, additional functional studies are required to elucidate their contribution to the pathophysiology to CVDs.

Population genetic polymorphisms of pharmacogenes in Zimbabwe, a potential guide for the safe and efficacious use of medicines in people of African ancestry

OBJECTIVE

Pharmacogenomics (PGx) is a clinically significant factor in the safe and efficacious use of medicines. While PGx knowledge is abundant for other populations, there are scarce PGx data on African populations and is little knowledge on drug-gene interactions for medicines used to treat diseases common in Africa. The aim of this study was to use a custom-designed open array to genotype clinically actionable variants in a Zimbabwean population. This study also identified some of the commonly used drugs in Zimbabwe and the associated genes involved in their metabolism.

METHODS

A custom-designed open array that covers 120 genetic variants was used to genotype 522 black Zimbabwean healthy volunteers using TaqMan-based single nucleotide polymorphism genotyping. Data were also accessed from Essential Drugs' List in Zimbabwe (EDLIZ), and the medicines were grouped into the associated biomarker groups based on their metabolism. We also estimated the national drug procurement levels for medicines that could benefit from PGx-guided use based on the data obtained from the national authorities in Zimbabwe.

RESULTS

The results demonstrate the applicability of an open-array chip in simultaneously determining multiple genetic variants in an individual, thus significantly reducing cost and time to generate PGx data. There were significantly high frequencies of African-specific variants, such as the CYP2D6*17 and *29 variants and the CYP2B6*18 variant. The data obtained showed that the Zimbabwean population exhibits PGx variations in genes important for the safe and efficacious use of drugs approved by the EDLIZ and are procured at significantly large amounts annually. The study has established a cohort of genotyped healthy volunteers that can be accessed and used in the conduct of clinical pharmacogenetic studies for drugs entering a market of people of predominantly African ancestry.

CONCLUSION

Our study demonstrated the potential benefit of integrating PGx in Zimbabwe for the safe and efficacious use of drugs that are commonly used.

Case Report: Diffuse Large B Cell Lymphoma After Cardiac Transplantation due to Anthracycline-Induced Dilated Cardiomyopathy in Pediatric Acute Lymphoblastic Leukemia

Anthracycline is a first-line chemotherapy drug used to treat childhood acute leukemia, which may cause cardiac toxicity including common arrhythmia, valve disease, pericardial effusion, and even rare cardiomyopathy and cardiac failure. We reported a 2-year-old boy who was treated irregularly for acute lymphoblastic leukemia with daunorubicin. After 26 months, his left ventricular ejection fraction decreased to 40% and progressively decreased to 20–30%. Then he successfully received a heart transplant and the myocardium was confirmed with dilated cardiomyopathy. Eight months after cardiac transplantation, he was admitted again for left neck mass and was diagnosed with monomorphic diffuse large B cell lymphoma associated with Epstein-Barr virus infection by biopsy. We present this case to highlight the importance of standard chemotherapy of daunorubicin, clinical prevention, and monitoring of anthracycline-induced cardiotoxicity in acute lymphoblastic leukemia children to ensure their good prognosis and long-term life quality.

Cardiovascular Health Status And Genetic Risk In Survivors of Childhood Neuroblastoma and Nephroblastoma Treated With Doxorubicin: Protocol of the Pharmacogenetic Part of the LESS-Anthra Cross-Sectional Cohort Study

BACKGROUND

In childhood cancer survivors (survival of 5 years or more after diagnosis), cardiac toxicity is the most common nonmalignant cause of death attributed to treatment-related consequences. Identifying patients at risk of developing late cardiac toxicity is therefore crucial to improving treatment outcomes. The use of genetic markers has been proposed, together with clinical risk factors, to predict individual risk of cardiac toxicity from cancer therapies, such as doxorubicin.

OBJECTIVE

The primary aim of this study is to evaluate the value of multimarker genetic testing for RARG rs2229774, UGT1A6 rs17863783, and SLC28A3 rs7853758 for predicting doxorubicin-induced cardiotoxicity. The secondary aim is to replicate previously described associations of candidate genetic markers with doxorubicin-induced cardiotoxicity. Moreover, we will evaluate the prevalence of cardiovascular dysfunction in childhood cancer survivors after neuroblastoma or nephroblastoma.

METHODS

This is the pharmacogenetic substudy of the research project Structural Optimization for Children With Cancer After Anthracycline Therapy (LESS-Anthra). We invited 2158 survivors of childhood neuroblastoma or nephroblastoma treated with doxorubicin according to the trial protocols of SIOP 9/GPOH, SIOP 93-01/GPOH, SIOP 2001/GPOH, NB 90, NB 97, or NB 2004 to participate in this prospective cross-sectional cohort study. The study participants underwent a cardiological examination and were asked to provide a blood or saliva sample for genotyping. The study participants' health statuses and cardiovascular diagnoses were recorded using a questionnaire completed by the cardiologist. Digital echocardiographic data were centrally evaluated to determine the contractile function parameters. Medical data on the tumor diagnosis and treatment protocol were taken from the study documentation. Survivors were screened for variants of several candidate genes by TaqMan genotyping.

RESULTS

This study includes 657 survivors treated with doxorubicin for childhood cancer, the largest German cohort assembled to date to investigate cardiovascular late effects. Data analyses are yet to be completed.

CONCLUSIONS

This study will define the genetic risk related to 3 marker genes proposed in a pharmacogenetic guideline for risk assessment. Moreover, the results of this study will show the prevalence of cardiovascular dysfunction in survivors of pediatric neuroblastoma or nephroblastoma who were treated with doxorubicin. The results will help to improve primary treatment and follow-up care, thus reducing cardiovascular late effects in the growing population of childhood cancer survivors.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00015084; https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00015084.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/27898.

Pharmacogenomic study of anthracycline-induced cardiotoxicity in Mexican pediatric patients

Background: The aim of this study was to evaluate the association between well-defined genetic risk variants in SLC28A3, RARG and UGT1A6 and anthracycline-induced cardiotoxicity in Mexican pediatric patients. Methods: We tested a cohort of 79 children treated with anthracyclines for the presence of SLC28A3-rs7853758, RARG-rs2229774 and UGT1A6-rs17863783. Results: The SLC28A3-rs7853758 variant was more frequent in this cohort, while the UGT1A6-rs17863783 and RARG-rs2229774 variants were present at lower frequencies. A clinically important decrease of fractional shortening was associated with SLC28A3-rs7853758 variant. Conclusion: In this cohort, 39.2% of patients carried the protective SLC28A3 variant. A small number of tested patients have the risk variants of UGT1A6 and RARG. None of the patients shared the two risk variants.

Role of genetic testing in cardiomyopathies: Α primer for cardiologists

Recent advances in cardiovascular genetics have transformed genetic testing into a valuable part of management of families with inherited cardiomyopathies. As novel mutations have been identified, understanding when to consider genetic testing has emerged as an important consideration in the management of these cases. Specific genetic testing has a paramount importance in the risk stratification of family members, in the prognosis of probands at higher risk of a serious phenotype expression, and finally in the identification of new mutations, all of which are discussed in this review. The indications for each type of cardiomyopathy are described, along with the limitations of genetic testing. Finally, the importance of public sharing of variants in large data sets is emphasized. The ultimate aim of this review is to present key messages about the genetic testing process in order to minimize potential harms and provide suggestions to specialized clinicians who act as a part of a multidisciplinary team in order to offer the best care to families with inherited cardiomyopathies.

Identification of Drug Transporter Genomic Variants and Inhibitors That Protect Against Doxorubicin-Induced Cardiotoxicity

BACKGROUND

Multiple pharmacogenomic studies have identified the synonymous genomic variant rs7853758 (G > A, L461L) and the intronic variant rs885004 in SLC28A3 (solute carrier family 28 member 3) as statistically associated with a lower incidence of anthracycline-induced cardiotoxicity. However, the true causal variant(s), the cardioprotective mechanism of this locus, the role of SLC28A3 and other solute carrier (SLC) transporters in anthracycline-induced cardiotoxicity, and the suitability of SLC transporters as targets for cardioprotective drugs has not been investigated.

METHODS

Six well-phenotyped, doxorubicin-treated pediatric patients from the original association study cohort were recruited again, and human induced pluripotent stem cell-derived cardiomyocytes were generated. Patient-specific doxorubicin-induced cardiotoxicity (DIC) was then characterized using assays of cell viability, activated caspase 3/7, and doxorubicin uptake. The role of SLC28A3 in DIC was then queried using overexpression and knockout of SLC28A3 in isogenic human-induced pluripotent stem cell-derived cardiomyocytes using a CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9). Fine-mapping of the SLC28A3 locus was then completed after SLC28A3 resequencing and an extended in silico haplotype and functional analysis. Genome editing of the potential causal variant was done using cytosine base editor. SLC28A3-AS1 overexpression was done using a lentiviral plasmid-based transduction and was validated using stranded RNA-sequencing after ribosomal RNA depletion. Drug screening was done using the Prestwick Chemical Library (n = 1200), followed by in vivo validation in mice. The effect of desipramine on doxorubicin cytotoxicity was also investigated in 8 cancer cell lines.

RESULTS

Here, using the most commonly used anthracycline, doxorubicin, we demonstrate that patient-derived cardiomyocytes recapitulate the cardioprotective effect of the SLC28A3 locus and that SLC28A3 expression influences the severity of DIC. Using Nanopore-based fine-mapping and base editing, we identify a novel cardioprotective single nucleotide polymorphism, rs11140490, in the SLC28A3 locus; its effect is exerted via regulation of an antisense long noncoding RNA (SLC28A3-AS1) that overlaps with SLC28A3. Using high-throughput drug screening in patient-derived cardiomyocytes and whole organism validation in mice, we identify the SLC competitive inhibitor desipramine as protective against DIC.

CONCLUSIONS

This work demonstrates the power of the human induced pluripotent stem cell model to take a single nucleotide polymorphism from a statistical association through to drug discovery, providing human cell-tested data for clinical trials to attenuate DIC.

Aristotle: stratified causal discovery for omics data

BACKGROUND

There has been a simultaneous increase in demand and accessibility across genomics, transcriptomics, proteomics and metabolomics data, known as omics data. This has encouraged widespread application of omics data in life sciences, from personalized medicine to the discovery of underlying pathophysiology of diseases. Causal analysis of omics data may provide important insight into the underlying biological mechanisms. Existing causal analysis methods yield promising results when identifying potential general causes of an observed outcome based on omics data. However, they may fail to discover the causes specific to a particular stratum of individuals and missing from others.

METHODS

To fill this gap, we introduce the problem of stratified causal discovery and propose a method, Aristotle, for solving it. Aristotle addresses the two challenges intrinsic to omics data: high dimensionality and hidden stratification. It employs existing biological knowledge and a state-of-the-art patient stratification method to tackle the above challenges and applies a quasi-experimental design method to each stratum to find stratum-specific potential causes.

RESULTS

Evaluation based on synthetic data shows better performance for Aristotle in discovering true causes under different conditions compared to existing causal discovery methods. Experiments on a real dataset on Anthracycline Cardiotoxicity indicate that Aristotle's predictions are consistent with the existing literature. Moreover, Aristotle makes additional predictions that suggest further investigations.

Extracellular matrix remodeling in anthracycline-induced cardiotoxicity: What place on the pedestal?

OBJECTIVE

To evaluate the role of matrix metalloproteinases (MMP)-2 and 9 and the gene polymorphisms of MMP-2 (rs243865) and MMP-9 (rs3918242) in the course of anthracycline-induced cardiotoxicity (AIC) in women without previous cardiovascular diseases (CVD) during 24-months.

METHODS

A total of 114 women (47.0 [44.0; 52.0] years old) with AIC of NYHA class I-III who received doxorubicin for breast cancer were enrolled.

RESULTS

After 24 months patients had breast cancer remission and were divided into 2 groups: group 1 comprised women with adverse course of AIC (n = 54), group 2 comprised those without it (n = 60). Serum levels of MMP-2 were higher by 8% (p = 0.017) MMP9 by 18.4% (p < 0.001) in group 1 than in group 2. In group 1 the levels of MMP-2 increased (p < 0.001) from 376.8 (329.5; 426.7) to 481.4 (389.8; 518.7) pg/mL, and MMP-9 increased (p < 0.001) from 23.6 (21.4; 24.6) to 26.0 (23.3; 27.0) pg/mL at 24 months. In group 2 the both MMP-2 and MMP-9 level decreased at 24 months. Based on ROC-analysis, the levels of MMP2 ≥ 388.2 pg/mL (AUС = 0.64; р = 0.013) and MMP-9 ≥ 21.25 pg/mL (AUС = 0.9; р < 0.001) were identified as predictors for adverse course of AIHF. The presence of C/C genotype of MMP2 (OR = 4.76; p = 0.029) and C/C genotype of MMP-9 (OR = 15.2; p < 0.0001) were related with adverse course of AIHF and higher levels of MMP-2 and MMP-9.

CONCLUSION

Gene polymorphisms of MMP-2 (rs243865) and MMP-9 (rs3918242) and serum levels of MMP-2 and MMP-9 levels in women without previous CVD were associated with adverse course of AIC during 24 months.

Pharmacogenetic testing to guide therapeutic decision-making and improve outcomes for children undergoing anthracycline-based chemotherapy

Anthracyclines are widely used as part of chemotherapeutic regimens in paediatric oncology patients. The most serious adverse drug reaction caused by anthracycline use is cardiotoxicity, a serious condition that can lead to cardiac dysfunction and subsequent heart failure. Both clinical and genetic factors contribute to a patient's risk of experiencing anthracycline-induced cardiotoxicity. In particular, genetic variants in RARG, UGT1A6 and SLC28A3 have been consistently shown to influence an individual's risk of experiencing this reaction. By combining clinical and genetic risks, decision-making can be improved to optimize treatment and prevent potentially serious adverse drug reactions. As part of a precision medicine initiative, we used pharmacogenetic testing, focused on RARG, UGT1A6 and SLC28A3 variants, to help predict an individual's risk of experiencing anthracycline-induced cardiotoxicity. Pharmacogenetic results are currently being used in clinical decision-making to inform treatment regimen choice, anthracycline dosing and decisions to initiate cardioprotective agents. In this case series, we demonstrate examples of the impact of genetic testing and discuss its potential to allow patients to be increasingly involved in their own treatment decisions.

Pharmacogenomics in Cytotoxic Chemotherapy of Cancer

Pharmacogenetic testing in patients with cancer requiring cytotoxic chemotherapy offers the potential to predict, prevent, and mitigate chemotherapy-related toxicities. While multiple drug-gene pairs have been identified and studied, few drug-gene pairs are currently used routinely in the clinical status. Here we review what is known, theorized, and unknown regarding the use of pharmacogenetic testing in cancer.

Cardiotoxicity in pediatric lymphoma survivors

INTRODUCTION

Over the past five decades, the diagnosis and management of children with various malignancies have improved tremendously. As a result, an increasing number of children are long-term cancer survivors. With improved survival, however, has come an increased risk of treatment-related cardiovascular complications that can appear decades later.

AREAS COVERED

This review discusses the pathophysiology, epidemiology and effects of treatment-related cardiovascular complications from anthracyclines and radiotherapy in pediatric lymphoma survivors. There is a paucity of evidence-based recommendations for screening for and treatment of cancer therapy-induced cardiovascular complications. We discuss current preventive measures and strategies for their treatment.

EXPERT OPINION

Significant cardiac adverse effects occur due to radiation and chemotherapy received by patients treated for lymphoma. Higher lifetime cumulative doses, female sex, longer follow-up, younger age, and preexisting cardiovascular disease are associated with a higher incidence of cardiotoxicity. With deeper understanding of the mechanisms of these adverse cardiac effects and identification of driver mutations causing these effects, personalized cancer therapy to limit cardiotoxic effects while ensuring an adequate anti-neoplastic effect would be ideal. In the meantime, expanding the use of cardioprotective agents with the best evidence such as dexrazoxane should be encouraged and further studied.

Pharmacogenomic testing in paediatrics: clinical implementation strategies

Pharmacogenomics (PGx) relates to the study of genetic factors determining variability in drug response. Implementing PGx testing in paediatric patients can enhance drug safety, helping to improve drug efficacy or reduce the risk of toxicity. Despite its clinical relevance, the implementation of PGx testing in paediatric practice to date has been variable and limited.

As with most paediatric pharmacological studies, there are well‐recognised barriers to obtaining high‐quality PGx evidence, particularly when patient numbers may be small, and off‐label or unlicensed prescribing remains widespread. Furthermore, trials enrolling small numbers of children can rarely, in isolation, provide sufficient PGx evidence to change clinical practice, so extrapolation from larger PGx studies in adult patients, where scientifically sound, is essential.

This review paper discusses the relevance of PGx to paediatrics and considers implementation strategies from a child health perspective. Examples are provided from Canada, the Netherlands and the UK, with consideration of the different healthcare systems and their distinct approaches to implementation, followed by future recommendations based on these cumulative experiences.

Improving the evidence base demonstrating the clinical utility and cost‐effectiveness of paediatric PGx testing will be critical to drive implementation forwards. International, interdisciplinary collaborations will enhance paediatric data collation, interpretation and evidence curation, while also supporting dedicated paediatric PGx educational initiatives. PGx consortia and paediatric clinical research networks will continue to play a central role in the streamlined development of effective PGx implementation strategies to help optimise paediatric pharmacotherapy.

Pharmacogenomics insights into precision pediatric oncology

PURPOSE OF REVIEW

Pharmacogenomic insights provide an opportunity to optimize medication dosing regimens and patient outcomes. However, the potential for interindividual genomic variability to guide medication dosing and toxicity monitoring is not yet standard of care. In this review, we present advances for the thiopurines, anthracyclines and vincristine and provide perspectives on the actionability of pharmacogenomic guidance in the future.

RECENT FINDINGS

The current guideline on thiopurines recommends that those with normal predicted thiopurine methyltransferase and NUDT15 expression receive standard-of-care dosing, while 'poor metabolizer' haplotypes receive a decreased 6-mercaptopurine starting dose to avoid bone marrow toxicity. Emerging evidence established significant polygenic contributions that predispose to anthracycline-induced cardiotoxicity and suggest this knowledge be used to identify those at higher risk of complications. In the case of vincristine, children who express CYP3A5 have a significantly reduced risk of peripheral neuropathy compared with those expressing an inactive form or the CYP3A4 isoform.

SUMMARY

The need for adequately powered pediatric clinical trials, coupled with the study of epigenetic mechanisms and their influence on phenotypic variation and the integration of precision survivorship into precision approaches are featured as important areas for focused investments in the future.

POLRMT as a Novel Susceptibility Gene for Cardiotoxicity in Epirubicin Treatment of Breast Cancer Patients

Anthracyclines are among the most used chemotherapeutic agents in breast cancer (BC). However their use is hampered by anthracycline-induced cardiotoxicity (AIC). The currently known clinical and genetic risk factors do not fully explain the observed inter-individual variability and only have a limited ability to predict which patients are more likely to develop this severe toxicity. To identify novel predictive genes, we conducted a two-stage genome-wide association study in epirubicin-treated BC patients. In the discovery phase, we genotyped over 700,000 single nucleotide variants in a cohort of 227 patients. The most interesting finding was rs62134260, located 4kb upstream of POLRMT (OR = 5.76, P = 2.23 × 10-5). We replicated this association in a validation cohort of 123 patients (P = 0.021). This variant regulates the expression of POLRMT, a gene that encodes a mitochondrial DNA-directed RNA polymerase, responsible for mitochondrial gene expression. Individuals harbouring the risk allele had a decreased expression of POLRMT in heart tissue that may cause an impaired capacity to maintain a healthy mitochondrial population in cardiomyocytes under stressful conditions, as is treatment with epirubicin. This finding suggests a novel molecular mechanism involved in the development of AIC and may improve our ability to predict patients who are at risk.

Leveraging Clinical Informatics Tools to Extract Cumulative Anthracycline Exposure, Measure Cardiovascular Outcomes, and Assess Guideline Adherence for Children With Cancer

PURPOSE

Cardiovascular disease is a significant cause of late morbidity and mortality in survivors of childhood cancer. Clinical informatics tools could enhance provider adherence to echocardiogram guidelines for early detection of late-onset cardiomyopathy.

METHODS

Cancer registry data were linked to electronic health record data. Structured query language facilitated the construction of anthracycline-exposed cohorts at a single institution. Primary outcomes included the data quality from automatic anthracycline extraction, sensitivity of International Classification of Disease coding for heart failure, and adherence to echocardiogram guideline recommendations.

RESULTS

The final analytic cohort included 385 pediatric oncology patients diagnosed between July 1, 2013, and December 31, 2018, among whom 194 were classified as no anthracycline exposure, 143 had low anthracycline exposure (< 250 mg/m²), and 48 had high anthracycline exposure (≥ 250 mg/m²). Manual review of anthracycline exposure was highly concordant (95%) with the automatic extraction. Among the unexposed group, 15% had an anthracycline administered at an outside institution not captured by standard query language coding. Manual review of echocardiogram parameters and clinic notes yielded a sensitivity of 75%, specificity of 98%, and positive predictive value of 68% for International Classification of Disease coding of heart failure. For patients with anthracycline exposure, 78.5% (n = 62) were adherent to guideline recommendations for echocardiogram surveillance. There were significant association with provider adherence and race and ethnicity (P = .047), and 50% of patients with Spanish as their primary language were adherent compared with 90% of patients with English as their primary language (P = .003).

CONCLUSION

Extraction of treatment exposures from the electronic health record through clinical informatics and integration with cancer registry data represents a feasible approach to assess cardiovascular disease outcomes and adherence to guideline recommendations for survivors.