The dilemma of the strive for apoptosis in oncology: mind the heart

Cardio-protective impact of gabapentin against doxorubicin-induced myocardial toxicity in rats; emphasis on modulation of inflammatory-apoptotic signaling

PURPOSE

Cardiotoxicity is one of the most commonly encountered adverse effects observed alongside the therapeutic use of doxorubicin (DOX), thus curbing its therapeutic utility.

METHODS

The current study was conducted to evaluate the cardioprotective effect of gabapentin (Gaba), a Ca + 2 channel blocker with emerging pharmacological merits, against DOX-induced cardiotoxicity. Gaba was orally administered at two dose levels (10 and 30 mg/kg) for 21 days parallel to DOX injection.

RESULTS

DOX induced significant functional, biochemical, and histopathological injury to the myocardium. Gaba treatment revealed a cardioprotective effect as manifested in the significant restoration of electrocardiogram parameters, including the heart rate, ST segment elevation, QRS and T wave amplitudes, and QT and PR intervals. The biomarkers of myocardial injury, namely serum creatine kinase, aspartate aminotransferase, and lactate dehydrogenase activities, significantly declined as well as the concomitant improvement of the myocardial oxidative status. Mechanistically, Gaba treatment significantly reduced the myocardial contents of c-Jun N-terminal kinase (JNK), the major modulator of inflammatory/apoptotic signaling. However, the myocardial contents of the apoptotic biomarkers caspase-8 and TRAIL also significantly declined. In isolated cardiomyocytes, Gaba treatment maintained the morphological characteristics of the cardiomyocytes and preserved their spontaneous beating characteristics. Nevertheless, the protein expression of caspase-8, JNK 1/2, and CD95L significantly declined with Gaba treatment.

CONCLUSION

Gaba confers cardioprotective effects against DOX-induced myocardial injury and cardiotoxicity by modulating the inflammatory/apoptotic signaling pathway.

Pharmacogenomic and Pharmacotranscriptomic Profiling of Childhood Acute Lymphoblastic Leukemia: Paving the Way to Personalized Treatment

Personalized medicine is focused on research disciplines which contribute to the individualization of therapy, like pharmacogenomics and pharmacotranscriptomics. Acute lymphoblastic leukemia (ALL) is the most common malignancy of childhood. It is one of the pediatric malignancies with the highest cure rate, but still a lethal outcome due to therapy accounts for 1%⁻3% of deaths. Further improvement of treatment protocols is needed through the implementation of pharmacogenomics and pharmacotranscriptomics. Emerging high-throughput technologies, including microarrays and next-generation sequencing, have provided an enormous amount of molecular data with the potential to be implemented in childhood ALL treatment protocols. In the current review, we summarized the contribution of these novel technologies to the pharmacogenomics and pharmacotranscriptomics of childhood ALL. We have presented data on molecular markers responsible for the efficacy, side effects, and toxicity of the drugs commonly used for childhood ALL treatment, i.e., glucocorticoids, vincristine, asparaginase, anthracyclines, thiopurines, and methotrexate. Big data was generated using high-throughput technologies, but their implementation in clinical practice is poor. Research efforts should be focused on data analysis and designing prediction models using machine learning algorithms. Bioinformatics tools and the implementation of artificial i Lack of association of the CEP72 rs924607 TT genotype with intelligence are expected to open the door wide for personalized medicine in the clinical practice of childhood ALL.

Doxorubicin induces cardiotoxicity through upregulation of death receptors mediated apoptosis in cardiomyocytes

Doxorubicin is a highly effective anticancer agent but causes cardiotoxicity in many patients. The mechanisms of doxorubicin-induced cardiotoxicity remain incompletely understood. Here we investigated doxorubicin-induced cytotoxicity in human induced pluripotent stem cells-derived cardiomyocytes (iPS-CMs). We found that doxorubicin and related anthracycline agents (e.g., daunorubicin, idarubicin, and epirubicin) significantly upregulated the expression of death receptors (DRs) (TNFR1, Fas, DR4 and DR5) in iPS-derived cardiomyocytes at both protein and mRNA levels. The resulting iPS-CMs cells underwent spontaneous apoptosis which was further enhanced by physiologically relevant death ligands including TNF-related apoptosis inducing ligand (TRAIL). Furthermore, TRAIL potentiated doxorubicin-induced decrease in beating rate and amplitude of iPS-derived cardiomyocytes. These data demonstrate that the induction of death receptors in cardiomyocytes is likely a critical mechanism by which doxorubicin causes cardiotoxicity.

Targeting Apoptosis with Dietary Bioactive Agents

Apoptosis, a form of programmed cell death, is a pivotal defense against the occurrence of cancer and is essential to metazoans in maintaining tissue homeostasis. Apoptosis exhibits a distinctive phenotype and involves elimination of potentially deleterious cells. Many diseases have been associated with aberrantly regulated apoptotic cell death, ultimately leading to inhibition of apoptosis and propagation of diseases such as cancer. Elucidation of the critical events associated with carcinogenesis provides the opportunity for dietary intervention to prevent cancer development through induction of apoptosis, Particularly by bioactive agents or functional foods. Diet is a significant environmental factor in the overall cancer process and can exacerbate or interfere with carcinogenesis. Apoptosis occurs primarily through two well-recognized pathways in cells, including the Intrinsic, or mitochondrial-mediated, effector mechanism and the extrinsic, or death receptor-mediated, effector mechanism. In addition to diet's effects on protein expression and function, evidence is also accumulating that a large number of dietary food components can exert effects on the human genome, either directly or indirectly, to modulate gene expression. In fact, many diet-related genes are involved in carcinogenesis as well as apoptosis, and thus are ultimately molecular targets for dietary chemopreventlon. There are multiple steps within pathways in which dietary components can alter gene expression and phenotypes of cells and thus influence cancer outcomes (nutritional transcriptomic effect). Thus, apoptosis is an emerging therapeutic target of bioactive agents of diet. In this review, the process of apoptosis is discussed and the potential mechanistic interaction of bioactive agents, as components of functional foods, is explored within the context of apoptosis.

Hyaluronan synthase 3 variant and anthracycline-related cardiomyopathy: a report from the children's oncology group

PURPOSE

The strong dose-dependent association between anthracyclines and cardiomyopathy is further exacerbated by the co-occurrence of cardiovascular risk factors (diabetes and hypertension). The high morbidity associated with cardiomyopathy necessitates an understanding of the underlying pathogenesis so that targeted interventions can be developed.

PATIENTS AND METHODS

By using a two-stage design, we investigated host susceptibility to anthracycline-related cardiomyopathy by using the ITMAT/Broad CARe cardiovascular single nucleotide polymorphism (SNP) array to profile common SNPs in 2,100 genes considered relevant to de novo cardiovascular disease.

RESULTS

By using a matched case-control design (93 cases, 194 controls), we identified a common SNP, rs2232228, in the hyaluronan synthase 3 (HAS3) gene that exerts a modifying effect on anthracycline dose-dependent cardiomyopathy risk (P = 5.3 × 10(-7)). Among individuals with rs2232228 GG genotype, cardiomyopathy was infrequent and not dose related. However, in individuals exposed to high-dose (> 250 mg/m(2)) anthracyclines, the rs2232228 AA genotype conferred an 8.9-fold (95% CI, 2.1- to 37.5-fold; P = .003) increased cardiomyopathy risk compared with the GG genotype. This gene-environment interaction was successfully replicated in an independent set of 76 patients with anthracycline-related cardiomyopathy. Relative HAS3 mRNA levels measured in healthy hearts tended to be lower among individuals with AA compared with GA genotypes (P = .09).

CONCLUSION

Hyaluronan (HA) produced by HAS3 is a ubiquitous component of the extracellular matrix and plays an active role in tissue remodeling. In addition, HA is known to reduce reactive oxygen species (ROS) -induced cardiac injury. The high cardiomyopathy risk associated with AA genotype could be due to inadequate remodeling and/or inadequate protection of the heart from ROS-mediated injury on high anthracycline exposure.

Lupeol: connotations for chemoprevention

The perception of chemoprevention lies still in its infancy. Intervention, to slow down, arrest or reverse the process of carcinogenesis, by the use of either natural or synthetic substances individually or in combination therapy has emerged as a promising and pragmatic medical approach to reduce cancer risk. Pentacyclic lupane-type triterpenes exemplified by lupeol [lup-20(29)-en-3b-ol], are principally found in common fruit plants such as olive, mango, fig, etc. Although, lupeol exhibits an array of biological activities like anti-inflammatory, anti-arthritic, anti-mutagenic and anti-malarial activity both in in vitro and in vivo systems yet, extensive exploration in regard to establish its role as chemopreventive compound is warranted. Interest in developing lupeol based potent anti-neoplastic agents, has led to the discovery of a host of highly active derivatives exhibiting greater potencies and better therapeutic indices. This review asserts on the chemopreventive prospects of lupeol and reveals potential chemoprevention drug targets, central to which are the cell cycle regulatory pathway genes and tries to explain the mechanism operating behind its action.

Malignant tumours of the heart: a review of tumour type, diagnosis and therapy

Primary cardiac neoplasms are rare and occur less commonly than metastatic disease of the heart. In this overview, current published studies concerning malignant neoplasms of the heart are reviewed, together with some insights into their aetiology, diagnosis and management. We searched medline using the subject 'cardiac neoplasms'. We selected about 110 articles from between 1973 and 2006, of which 76 sources were used to complete the review. Sarcomas are the most common cardiac tumours and include myxosarcoma, liposarcoma, angiosarcoma, fibrosarcoma, leiomyosarcoma, osteosarcoma, synovial sarcoma, rhabdomyosarcoma, neurofibrosarcoma, malignant fibrous histiocytoma and undifferentiated sarcoma. The classic symptoms of cardiac tumours are intracardiac obstruction, signs of systemic embolisation, and systemic or constitutional symptoms. However, serious complications including stroke, myocardial infarction and even sudden death from arrhythmia may be the first signs of a tumour. Echocardiography and angiography are essential diagnostic tools for evaluating cardiac neoplasms. Computed tomography and magnetic resonance imaging studies have improved the diagnostic approach in recent decades. Successful treatment for benign cardiac tumours is usually achieved by surgical resection. Unfortunately, resection of the tumour is not always feasible. The prognosis after surgery is usually excellent in the case of benign tumours, but the prognosis of malignant tumours remains dismal. In conclusion, there are limited published data concerning cardiac neoplasms. Therefore, a high level of suspicion is required for early diagnosis. Surgery is the cornerstone of therapy. However, a multi-treatment approach, including chemotherapy, radiation as well as evolving approaches such as gene therapy, might provide a better palliative and curative result.

Apoptosis: a basic biological phenomenon with wide-ranging implications in human disease

Apoptosis is a highly regulated process of cell deletion and plays a fundamental role in the maintenance of tissue homeostasis in the adult organism. Numerous studies in recent years have revealed that apoptosis is a constitutive suicide programme expressed in most, if not all cells, and can be triggered by a variety of extrinsic and intrinsic signals. Many human diseases can be attributed directly or indirectly to a derangement of apoptosis, resulting in either cell accumulation, in which cell eradication or cell turnover is impaired, or cell loss, in which the apoptotic programme is inadvertently triggered. In addition, defective macrophage engulfment and degradation of cell corpses may also contribute to a dysregulation of tissue homeostasis. An increased understanding of the signalling pathways that govern the execution of apoptosis and the subsequent clearance of dying cells may thus yield novel targets for therapeutic intervention in a wide range of human maladies.