Molecular mechanisms of carfilzomib-induced cardiotoxicity in mice and the emerging cardioprotective role of metformin

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

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

Insulin-Degrading Enzyme Is a Non Proteasomal Target of Carfilzomib and Affects the 20S Proteasome Inhibition by the Drug

Carfilzomib is a last generation proteasome inhibitor (PI) with proven clinical efficacy in the treatment of relapsed/refractory multiple myeloma. This drug is considered to be extremely specific in inhibiting the chymotrypsin-like activity of the 20S proteasome, encoded by the β5 subunit, overcoming some bortezomib limitations, the first PI approved for multiple myeloma therapy which is however burdened by a significant toxicity profile, due also to its off-target effects. Here, molecular approaches coupled with molecular docking studies have been used to unveil that the Insulin-Degrading Enzyme, a ubiquitous and highly conserved Zn2+ peptidase, often found to associate with proteasome in cell-based models, is targeted by carfilzomib in vitro. The drug behaves as a modulator of IDE activity, displaying an inhibitory effect over 10-fold lower than for the 20S. Notably, the interaction of IDE with the 20S enhances in vitro the inhibitory power of carfilzomib on proteasome, so that the IDE-20S complex is an even better target of carfilzomib than the 20S alone. Furthermore, IDE gene silencing after delivery of antisense oligonucleotides (siRNA) significantly reduced carfilzomib cytotoxicity in rMC1 cells, a validated model of Muller glia, suggesting that, in cells, the inhibitory activity of this drug on cell proliferation is somewhat linked to IDE and, possibly, also to its interaction with proteasome.

The Role of Proteasome Inhibitors in Treating Acute Lymphoblastic Leukaemia

Acute lymphoblastic leukaemia (ALL) is an aggressive haematolymphoid malignancy. The prognosis of ALL is excellent in paediatric population, however the outcome of relapse/refractory disease is dismal. Adult ALL has less favourable prognosis and relapse/refractory disease is not uncommonly encountered. Bortezomib is the first generation proteasome inhibitor licensed to treat plasma cell myeloma and mantle cell lymphoma with favourable side effect profile. Efficacy of bortezomib had been proven in other solid tumors. Clinical studies showed promising response for proteasome inhibitors in treating relapse/refractory ALL. Thus, proteasome inhibitors are attractive alternative agents for research in treating ALL. In the review article, we will introduce different proteasome inhibitors and their difference in pharmacological properties. Moreover, the mechanism of action of proteasome inhibitors on ALL will be highlighted. Finally, results of various clinical studies on proteasome inhibitors in both paediatric and adult ALL will be discussed. This review article provides the insights on the use of proteasome inhibitors in treating ALL with a summary of mechanism of action in ALL which facilitates future research on its use to improve the outcome of ALL.

Carfilzomib Treatment Causes Molecular and Functional Alterations of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Background Anticancer therapies have significantly improved patient outcomes; however, cardiac side effects from cancer therapies remain a significant challenge. Cardiotoxicity following treatment with proteasome inhibitors such as carfilzomib is known in clinical settings, but the underlying mechanisms have not been fully elucidated. Methods and Results Using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) as a cell model for drug-induced cytotoxicity in combination with traction force microscopy, functional assessments, high-throughput imaging, and comprehensive omic analyses, we examined the molecular mechanisms involved in structural and functional alterations induced by carfilzomib in hiPSC-CMs. Following the treatment of hiPSC-CMs with carfilzomib at 0.01 to 10 µmol/L, we observed a concentration-dependent increase in carfilzomib-induced toxicity and corresponding morphological, structural, and functional changes. Carfilzomib treatment reduced mitochondrial membrane potential, ATP production, and mitochondrial oxidative respiration and increased mitochondrial oxidative stress. In addition, carfilzomib treatment affected contractility of hiPSC-CMs in 3-dimensional microtissues. At a single cell level, carfilzomib treatment impaired Ca²⁺ transients and reduced integrin-mediated traction forces as detected by piconewton tension sensors. Transcriptomic and proteomic analyses revealed that carfilzomib treatment downregulated the expression of genes involved in extracellular matrices, integrin complex, and cardiac contraction, and upregulated stress responsive proteins including heat shock proteins. Conclusions Carfilzomib treatment causes deleterious changes in cellular and functional characteristics of hiPSC-CMs. Insights into these changes could be gained from the changes in the expression of genes and proteins identified from our omic analyses.

Recent Research Progress of Chiral Small Molecular Antitumor-Targeted Drugs Approved by the FDA From 2011 to 2019

Chiral drugs usually contain chiral centers, which are present as single enantiomers or racemates. Compared with achiral drugs, they have significant advantages in safety and efficacy with high stereoselectivity. Of these drugs, chirality not only exerts influence on the solubility and pharmacokinetic characteristics but also has specific mechanistic characteristics on their targets. We noted that small molecules with unique chiral properties have emerged as novel components of antitumor drugs approved by the FDA in decade. Since approved, these drugs have been continuously explored for new indications, new mechanisms, and novel combinations. In this mini review, recent research progress of twenty-two FDA-approved chiral small molecular-targeted antitumor drugs from 2011 to 2019 is summarized with highlighting the potential and advantages of their applications. We believe that these updated achievements may provide theoretical foundation and stimulate research interests for optimizing drug efficacy, expanding clinical application, overcoming drug resistance, and advancing safety in future clinical administrations of these chiral targeted drugs.

Protein phosphatase 2A in the healthy and failing heart: New insights and therapeutic opportunities

Protein phosphatases have emerged as critical regulators of phosphoprotein homeostasis in settings of health and disease. Protein phosphatase 2A (PP2A) encompasses a large subfamily of enzymes that remove phosphate groups from serine/threonine residues within phosphoproteins. The heterogeneity in PP2A structure, which arises from the grouping of different catalytic, scaffolding and regulatory subunit isoforms, creates distinct populations of catalytically active enzymes (i.e. holoenzymes) that localise to different parts of the cell. This structural complexity, combined with other regulatory mechanisms, such as interaction of PP2A heterotrimers with accessory proteins and post-translational modification of the catalytic and/or regulatory subunits, enables PP2A holoenzymes to target phosphoprotein substrates in a highly specific manner. In this review, we summarise the roles of PP2A in cardiac physiology and disease. PP2A modulates numerous processes that are vital for heart function including calcium handling, contractility, β-adrenergic signalling, metabolism and transcription. Dysregulation of PP2A has been observed in human cardiac disease settings, including heart failure and atrial fibrillation. Efforts are underway, particularly in the cancer field, to develop therapeutics targeting PP2A activity. The development of small molecule activators of PP2A (SMAPs) and other compounds that selectively target specific PP2A holoenzymes (e.g. PP2A/B56α and PP2A/B56ε) will improve understanding of the function of different PP2A species in the heart, and may lead to the development of therapeutics for normalising aberrant protein phosphorylation in settings of cardiac remodelling and dysfunction.

Carfilzomib: A Promising Proteasome Inhibitor for the Treatment of Relapsed and Refractory Multiple Myeloma

The proteasome is crucial for the degradation of intracellular proteins and plays an important role in mediating a number of cell survival and progression events by controlling the levels of key regulatory proteins such as cyclins and caspases in both normal and tumor cells. However, compared to normal cells, cancer cells are more dependent on the ubiquitin proteasome pathway (UPP) due to the accumulation of proteins in response to uncontrolled gene transcription, allowing proteasome to become a potent therapeutic target for human cancers such as multiple myeloma (MM). Up to date, three proteasome inhibitors namely bortezomib (2003), carfilzomib (2012) and ixazomib (2015) have been approved by the US Food and Drug Administration (FDA) for the treatment of patients with relapsed and/or refractory MM. This review mainly focuses on the biochemical properties, mechanism of action, toxicity profile and pivotal clinical trials related to carfilzomib, a second-generation proteasome inhibitor that binds irreversibly with proteasome to overcome the major toxicities and resistance associated with bortezomib.

Non-selective proteasome inhibitors in multiple myeloma and future perspectives

INTRODUCTION

: The ubiquitination system is the most important cascade of protein degradation independently of lysosomal function. The proteasome system is actively involved in cell cycle regulation. Therefore, proteasome inhibition can lead to inhibition of tumor cell proliferation, and therefore it constitutes a potential therapeutic anticancer approach especially in the therapeutic algorithm of patients with multiple myeloma.

AREAS COVERED

Three different proteasome inhibitors are currently approved, bortezomib, carfilzomib and ixazomib, and they have been investigated in multiple myeloma and other hematological malignancies. Multiple myeloma cells are extremely sensitive to this inhibition which leads to accumulation of proteins and endoplasmic reticulum stress, leading finally to apoptosis. However, these agents lack specificity, since they target both the constitutive proteasome and the immunoproteasome. Targeting the constitutive proteasome is the main reason for side toxicity due to the effect on normal tissues. In contrary, immunoproteasome inhibition may reduce the adverse events while maintaining the therapeutic efficacy. In this review the authors present the role of the available proteasome inhibitors in myeloma therapeutics and future perspectives of both selective and non-selective proteasome inhibitors.

EXPERT OPINION

The available non-selective proteasome inhibitors have changed the therapeutics of multiple myeloma the last 10 years and have significantly improved the clinical outcomes of the patients. Furthermore, selective proteasome inhibitors are now under preclinical investigation and there is hope that their optimization will come with an improved safety profile with at least comparable efficacy.

Improved nonclinical safety profile of a novel, highly selective inhibitor of the immunoproteasome subunit LMP7 (M3258)

M3258 is the first selective inhibitor of the immunoproteasome subunit LMP7 (Large multifunctional protease 7) in early clinical development with the potential to improve therapeutic utility in patients of multiple myeloma (MM) or other hematological malignancies. Safety pharmacology studies with M3258 did not reveal any functional impairments of the cardiovascular system in several in vitro tests employing human cardiomyocytes and cardiac ion channels (including hERG), guinea pig heart refractory period and force contraction, and rat aortic contraction as well as in cardiovascular function tests in dogs. Following single dose M3258 administration to rats, no changes were observed on respiratory function by using whole body plethysmography, nor did it change (neuro)behavioral parameters in a battery of tests. Based on pivotal 4-week toxicity studies with daily oral dosing of M3258, the identified key target organs of toxicity were limited to the lympho-hematopoietic system in rats and dogs, and to the intestine with its local lymphoid tissues in dogs only. Importantly, the stomach, nervous system, heart, lungs, and kidneys, that may be part of clinically relevant toxicities as reported for pan-proteasome inhibitors, were spared with M3258. Therefore, it is anticipated that by targeting highly selective and potent inhibition of LMP7, the resulting favorable safety profile of M3258 together with the maintained potent anti-tumor activity as previously reported in mouse MM xenograft models, may translate into an improved benefit-risk profile in MM patients.

Elucidating Carfilzomib's Induced Cardiotoxicity in an In Vivo Model of Aging: Prophylactic Potential of Metformin

Background: Carfilzomib is a first-line proteasome inhibitor indicated for relapsed/refractory multiple myeloma (MM), with its clinical use being hampered by cardiotoxic phenomena. We have previously established a translational model of carfilzomib cardiotoxicity in young adult mice, in which metformin emerged as a prophylactic therapy. Considering that MM is an elderly disease and that age is an independent risk factor for cardiotoxicity, herein, we sought to validate carfilzomib’s cardiotoxicity in an in vivo model of aging. Methods: Aged mice underwent the translational two- and four-dose protocols without and with metformin. Mice underwent echocardiography and were subsequently sacrificed for molecular analyses in the blood and cardiac tissue. Results: Carfilzomib decreased proteasomal activity both in PBMCs and myocardium in both protocols. Carfilzomib induced mild cardiotoxicity after two doses and more pronounced cardiomyopathy in the four-dose protocol, while metformin maintained cardiac function. Carfilzomib led to an increased Bip expression and decreased AMPKα phosphorylation, while metformin coadministration partially decreased Bip expression and induced AMPKα phosphorylation, leading to enhanced myocardial LC3B-dependent autophagy. Conclusion: Carfilzomib induced cardiotoxicity in aged mice, an effect significantly reversed by metformin. The latter possesses translational importance as it further supports the clinical use of metformin as a potent prophylactic therapy.

Daratumumab May Attenuate Cardiac Dysfunction Related to Carfilzomib in Patients with Relapsed/Refractory Multiple Myeloma: A Prospective Study

Simple Summary

The management of cardiovascular adverse events in patients with relapsed/refractory multiple myeloma undergoing treatment with carfilzomib can be challenging. Herein, we evaluated the potential cardioprotective effect of daratumumab when administered in combination with carfilzomib and dexamethasone (DaraKd). The study included 25 patients receiving either DaraKd (n = 14) or Kd (n = 11) who were evaluated for echocardiographic changes at the sixth cycle of treatment compared with baseline assessment. DaraKd was associated with preserved post-treatment cardiac systolic function compared with Kd. CD38 inhibition by daratumumab might restore metabolic disequilibrium in the cardiac tissue and prevent cardiac injury. A trend for a lower rate of cardiovascular adverse events among patients receiving DaraKd was also evident, although larger studies are needed to determine the association between echocardiographic and/or biomarker changes with cardiovascular adverse events.

Abstract

Carfilzomib has improved survival in patients with relapsed/refractory multiple myeloma (RRMM), but it may exert cardiovascular adverse events (CVAEs). The aim of this study was to assess whether treatment with daratumumab may ameliorate carfilzomib-related toxicity. We prospectively evaluated 25 patients with RRMM who received either daratumumab in combination with carfilzomib and dexamethasone (DaraKd) (n = 14) or Kd (n = 11). Cardiac ultrasound was performed before treatment initiation and C6D16 or at the time of treatment interruption. Patients were followed for a median of 10 months for CVAEs. The mean (± SD) age was 67.8 ± 7.6 years and 60% were men. The two treatment groups did not significantly differ in baseline demographic characteristics (p > 0.1 for all). In the DaraKd group, we did not observe any significant change in markers of ventricular systolic function. However, these markers deteriorated in the Kd group; left ventricular (LV) ejection fraction, LV global longitudinal strain, tricuspid annular plane systolic excursion and RV free wall longitudinal strain significantly decreased from baseline to second visit (p < 0.05). A significant group interaction (p < 0.05) was observed for the abovementioned changes. CVAEs occurred more frequently in the Kd than the DaraKd group (45% vs. 28.6%). DaraKd was associated with preserved post-treatment cardiac systolic function and lower CVAE rate compared with Kd. The clinical significance and the underlying mechanisms merit further investigation.

The Hormetic Effect of Metformin: "Less Is More"?

Metformin (MTF) is the first-line therapy for type 2 diabetes (T2DM). The euglycemic effect of MTF is due to the inhibition of hepatic glucose production. Literature reports that the principal molecular mechanism of MTF is the activation of 5′-AMP-activated protein kinase (AMPK) due to the decrement of ATP intracellular content consequent to the inhibition of Complex I, although this effect is obtained only at millimolar concentrations. Conversely, micromolar MTF seems to activate the mitochondrial electron transport chain, increasing ATP production and limiting oxidative stress. This evidence sustains the idea that MTF exerts a hormetic effect based on its concentration in the target tissue. Therefore, in this review we describe the effects of MTF on T2DM on the principal target organs, such as liver, gut, adipose tissue, endothelium, heart, and skeletal muscle. In particular, data indicate that all organs, except the gut, accumulate MTF in the micromolar range when administered in therapeutic doses, unmasking molecular mechanisms that do not depend on Complex I inhibition.

Mechanisms and Potential Treatment Options of Heart Failure in Patients With Multiple Myeloma

Multiple myeloma is a pathology of plasma cells, with one of the most common side effects of its treatment is heart failure. In addition, cardiac amyloidosis could cause heart failure by itself. Even though mechanisms of cardiac amyloidosis are known, and they involve lysosomal dysfunction, reactive oxygen species (ROS) accumulation, and infiltrative effect by fibrils, there is no specific agent that could protect from these effects. While the molecular mechanism of doxorubicin cardiotoxicity via topoisomerase II β is established, the only FDA-approved agent for treatment is dexrazoxane. Liposomal doxorubicin can potentially improve response and decrease the development of heart failure due to microscopic liposomes that can accumulate and penetrate only tumor vasculature. Supplements that enhance mitochondrial biogenesis are also shown to improve doxorubicin-induced cardiotoxicity. Other agents, such as JR-311, ICRF-193, and ursolic acid, could potentially become new treatment options. Proteasome inhibitors, novel agents, have significantly improved survival rates among multiple myeloma patients. They act on a proteasome system that is highly active in cardiomyocytes and activates various molecular cascades in malignant cells, as well as in the heart, through nuclear factor kappa B (NF-kB), endoplasmic reticulum (ER), calcineurin-nuclear factor of activated T-cells (NFAT), and adenosine monophosphate-activated protein kinase (AMPKa)/autophagy pathways. Metformin, apremilast, and rutin have shown positive results in animal studies and may become a promising therapy as cardioprotective agents. This article aims to highlight the main molecular mechanisms of heart failure among patients with multiple myeloma and potential treatment options to facilitate the development and research of new preventive strategies. Hence, this will have a positive impact on life expectancy in patients with multiple myeloma.

Heart Failure With Targeted Cancer Therapies: Mechanisms and Cardioprotection

Oncology has seen growing use of newly developed targeted therapies. Although this has resulted in dramatic improvements in progression-free and overall survival, challenges in the management of toxicities related to longer-term treatment of these therapies have also become evident. Although a targeted approach often exploits the differences between cancer cells and noncancer cells, overlap in signaling pathways necessary for the maintenance of function and survival in multiple cell types has resulted in systemic toxicities. In particular, cardiovascular toxicities are of important concern. In this review, we highlight several targeted therapies commonly used across a variety of cancer types, including HER2 (human epidermal growth factor receptor 2)+ targeted therapies, tyrosine kinase inhibitors, immune checkpoint inhibitors, proteasome inhibitors, androgen deprivation therapies, and MEK (mitogen-activated protein kinase kinase)/BRAF (v-raf murine sarcoma viral oncogene homolog B) inhibitors. We present the oncological indications, heart failure incidence, hypothesized mechanisms of cardiotoxicity, and potential mechanistic rationale for specific cardioprotective strategies.

Anti-tumor activity of a novel proteasome inhibitor D395 against multiple myeloma and its lower cardiotoxicity compared with carfilzomib

Carfilzomib, a second-generation proteasome inhibitor, has significantly improved the survival rate of multiple myeloma (MM) patients, but its clinical application is still restricted by drug resistance and cardiotoxicity. Here, we identified a novel proteasome inhibitor, D395, and assessed its efficacy in treating MM as well as its cardiotoxicity at the preclinical level. The activities of purified and intracellular proteasomes were measured to determine the effect of D395 on the proteasome. CCK-8 and flow cytometry experiments were designed to evaluate the effects of D395 on cell growth and apoptosis. The effects of D395 and carfilzomib on serum enzyme activity, echocardiography features, cardiomyocyte morphology, and hERG channels were also compared. In our study, D395 was highly cytotoxic to MM cell lines and primary MM cells but not normal cells, and it was well tolerated in vivo. Similar to carfilzomib, D395 inhibited osteoclast differentiation in a dose-dependent manner. In particular, D395 exhibited lower cardiotoxicity than carfilzomib in all experiments. In conclusion, D395 is a novel irreversible proteasome inhibitor that has remarkable anti-MM activity and mild cardiotoxicity in vitro and in vivo.

Lactate Dehydrogenase B and Pyruvate Oxidation Pathway Associated With Carfilzomib-Related Cardiotoxicity in Multiple Myeloma Patients: Result of a Multi-Omics Integrative Analysis

Multiple myeloma (MM) is the second most frequent hematologic cancer in the United States. Carfilzomib (CFZ), an irreversible proteasome inhibitor being used to treat relapsed and refractory MM, has been associated with cardiotoxicity, including heart failure. We hypothesized that a multi-omics approach integrating data from different omics would provide insights into the mechanisms of CFZ-related cardiovascular adverse events (CVAEs). Plasma samples were collected from 13 MM patients treated with CFZ (including 7 with CVAEs and 6 with no CVAEs) at the University of Florida Health Cancer Center. These samples were evaluated in global metabolomic profiling, global proteomic profiling, and microRNA (miRNA) profiling. Integrative pathway analysis was performed to identify genes and pathways differentially expressed between patients with and without CVAEs. The proteomics analysis identified the up-regulation of lactate dehydrogenase B (LDHB) [fold change (FC) = 8.2, p = 0.01] in patients who experienced CVAEs. The metabolomics analysis identified lower plasma abundance of pyruvate (FC = 0.16, p = 0.0004) and higher abundance of lactate (FC = 2.4, p = 0.0001) in patients with CVAEs. Differential expression analysis of miRNAs profiling identified mir-146b to be up-regulatein (FC = 14, p = 0.046) in patients with CVAE. Pathway analysis suggested that the pyruvate fermentation to lactate pathway is associated with CFZ-CVAEs. In this pilot multi-omics integrative analysis, we observed the down-regulation of pyruvate and up-regulation of LDHB among patients who experienced CVAEs, suggesting the importance of the pyruvate oxidation pathway associated with mitochondrial dysfunction. Validation and further investigation in a larger independent cohort are warranted to better understand the mechanisms of CFZ-CVAEs.

Cancer Therapy-Related Cardiovascular Complications in Clinical Practice: Current Perspectives

Cardiovascular (CV) diseases and cancer are the leading causes of death in Europe and the United States. Both diseases have extensive overlap and share common risk factors, symptoms, and outcomes. As the number of patients with both cancer and CV diseases continues to rise, the field of cardio-oncology is gaining increased attention. A frequent problem during anti-cancer treatment is cardiotoxicity caused by the side-effects of chemo-, immuno-, targeted, and radiation therapies. This problem may manifest as acute coronary syndrome, myocarditis, arrhythmias, or heart failure. Modern cardio-oncology spans many different research areas. While some researchers focus on treating patients that have already developed cardiotoxicity, others aim to identify new methods for preventing cardiotoxicity before, during, and after anti-cancer therapy. Both groups share the common understanding that regular monitoring of cancer patients is the basis for optimal medical treatment. Optimal treatment can only be achieved through close cooperation between cardiologists and oncologists. This review summarizes the current views on cardio-oncology and discusses the cardiotoxicities associated with commonly used chemotherapeutics.

Incidence and Management of Carfilzomib-induced Cardiovascular Toxicity; A Systematic Review and Meta-analysis

BACKGROUND

The ASPIRE and ENDEAVOUR trials have shown cardiovascular adverse effects in patients treated with carfilzomib-based regimens. Therefore, we conducted this meta-analysis of published clinical trials to identify the cumulative incidence and risk of cardiovascular adverse effects due to carfilzomib.

METHODS

A systematic search of PubMed, Embase, Web of Science, and Cochrane library was performed, and we identified 45 prospective trials of carfilzomib with data on 5583 patients. Among all patients being treated with carfilzomib (N=5,583), 8.9% sustained all grade cardiotoxicity, while 4.4% sustained high-grade cardiotoxicity. All-grade hypertension was present in 13.2%, while the incidence of high-grade hypertension was 5.3%.

RESULT

The observed incidences of all-grade heart failure, edema, and ischemia were 5.1%, 20.7%, and 4.6% respectively. Likewise, for high-grade heart failure and edema observed incidence was 3.2%, and 2.7% respectively. There was no difference in the event rate of all and high-grade cardiotoxicity between newly diagnosed multiple myeloma and relapsed/refractory (p-value 0.42 and 0.86 respectively). Likewise, we did not observe any difference in the event rate of all and high-grade cardiotoxicity when carfilzomib was used as a single agent versus when used in combination therapy with other agents (p-value 0.43 and 0.73 respectively).

CONCLUSION

Carfilzomib is associated with a significant risk of cardiovascular toxicity and hypertension. With the increasing utilization of carfilzomib, it is critical for primary care physicians, oncologists and cardiologists to be aware of the risk of cardiotoxicity associated with the use of carfilzomib to recognize and treat baseline cardiovascular risk factors in such patients.

Pharmacology differences among proteasome inhibitors: Implications for their use in clinical practice

Preclinical and clinical investigation on proteasome as a druggable target in cancer has led to the development of proteasome inhibitors (PIs) with different pharmacodynamic and pharmacokinetic properties. For example, carfilzomib has a better safety profile and a lower risk of clinically relevant drug-drug interactions than bortezomib, whereas ixazomib can be orally administered on a weekly basis due to a very long elimination half-life and high systemic exposure. The purpose of this review article is to elucidate the quantitative and qualitative differences in potency, selectivity, pharmacokinetics, safety and drug-drug interactions of clinically validated PIs to provide useful information for their clinical use in real life setting.

Chronic Empagliflozin Treatment Reduces Myocardial Infarct Size in Nondiabetic Mice Through STAT-3-Mediated Protection on Microvascular Endothelial Cells and Reduction of Oxidative Stress

Aims: Empagliflozin (EMPA) demonstrates cardioprotective effects on diabetic myocardium but its infarct-sparing effects in normoglycemia remain unspecified. We investigated the acute and chronic effect of EMPA on infarct size after ischemia-reperfusion (I/R) injury and the mechanisms of cardioprotection in nondiabetic mice. Results: Chronic oral administration of EMPA (6 weeks) reduced myocardial infarct size after 30 min/2 h I/R (26.5% ± 3.9% vs 45.8% ± 3.3% in the control group, p < 0.01). Body weight, blood pressure, glucose levels, and cardiac function remained unchanged between groups. Acute administration of EMPA 24 or 4 h before I/R did not affect infarct size. Chronic EMPA treatment led to a significant reduction of oxidative stress biomarkers. STAT-3 (signal transducer and activator of transcription 3) was activated by Y(705) phosphorylation at the 10th minute of R, but it remained unchanged at 2 h of R and in the acute administration protocols. Proteomic analysis was employed to investigate signaling intermediates and revealed that chronic EMPA treatment regulates several pathways at reperfusion, including oxidative stress and integrin-related proteins that were further evaluated. Superoxide dismutase and vascular endothelial growth factor were increased throughout reperfusion. EMPA pretreatment (24 h) increased the viability of human microvascular endothelial cells in normoxia and on 3 h hypoxia/1 h reoxygenation and reduced reactive oxygen species production. In EMPA-treated murine hearts, CD31-/VEGFR2-positive endothelial cells and the pSTAT-3(Y705) signal derived from endothelial cells were boosted at early reperfusion. Innovation: Chronic EMPA administration reduces infarct size in healthy mice via the STAT-3 pathway and increases the survival of endothelial cells. Conclusion: Chronic but not acute administration of EMPA reduces infarct size through STAT-3 activation independently of diabetes mellitus.

Carfilzomib in Combination with Bortezomib Enhances Apoptotic Cell Death in B16-F1 Melanoma Cells

Simple Summary

The incidence rate of metastatic melanoma has been rapidly increasing worldwide and its 5-year survival rate is very low. Due to partial responses, various side effects, and resistance to any known cancer therapeutics, more potent and safer therapeutics are needed to increase the survival rate of patients with melanoma. Since proteasome inhibitors, such as bortezomib and carfilzomib, have been suggested as treatments for various cancers, we investigated their potential for the treatment of melanoma by studying their molecular mechanisms of action in B16-F1 melanoma cells. In this study, we found that both bortezomib and carfilzomib lead to apoptosis via ER stress as well as ROS accumulation and MMP loss in melanoma cells. Bortezomib and carfilzomib synergistically reduced B16-F1 tumor growth in vitro and in a C57BL/6 xenograft mouse model. Therefore, a combination therapy with carfilzomib and bortezomib at submaximal concentrations may reduce their side effects and be beneficial for melanoma treatment.

Abstract

Proteasome inhibitors, such as bortezomib (BZ) and carfilzomib (CFZ), have been suggested as treatments for various cancers. To utilize BZ and/or CFZ as effective therapeutics for treating melanoma, we studied their molecular mechanisms using B16-F1 melanoma cells. Flow cytometry of Annexin V-fluorescein isothiocyanate-labeled cells indicated apoptosis induction by treatment with BZ and CFZ. Apoptosis was evidenced by the activation of various caspases, including caspase 3, 8, 9, and 12. Treatment with BZ and CFZ induced endoplasmic reticulum (ER) stress, as indicated by an increase in eIF2α phosphorylation and the expression of ER stress-associated proteins, including GRP78, ATF6α, ATF4, XBP1, and CCAAT/enhancer-binding protein homologous protein. The effects of CFZ on ER stress and apoptosis were lower than that of BZ. Nevertheless, CFZ and BZ synergistically induced ER stress and apoptosis in B16-F1 cells. Furthermore, the combinational pharmacological interactions of BZ and CFZ against the growth of B16-F1 melanoma cells were assessed by calculating the combination index and dose-reduction index with the CompuSyn software. We found that the combination of CFZ and BZ at submaximal concentrations could obtain dose reduction by exerting synergistic inhibitory effects on cell growth. Moreover, this drug combination reduced tumor growth in C57BL/6 syngeneic mice. Taken together, these results suggest that CFZ in combination with BZ may be a beneficial and potential strategy for melanoma treatment.

Carfilzomib-induced endothelial dysfunction, recovery of proteasome activity, and prediction of cardiovascular complications: a prospective study

Carfilzomib (CFZ) improves survival in relapsed/refractory multiple myeloma but is associated with cardiovascular adverse events (CVAEs). We prospectively investigated the effect of CFZ on endothelial function and associations with CVAEs. Forty-eight patients treated with Kd (CFZ 20/56 mg/m² and dexamethasone) underwent serial endothelial function evaluation, using brachial artery flow-mediated dilatation (FMD) and 26S proteasome activity (PrA) measurement in PBMCs; patients were followed until disease progression or cycle 6 for a median of 10 months. FMD and PrA decreased acutely after the first dose (p < 0.01) and FMD decreased at cycles 3 and 6 compared to baseline (p ≤ 0.05). FMD changes were associated with CFZ-induced PrA changes (p < 0.05) and lower PrA recovery during first cycle was associated with more prominent FMD decrease (p = 0.034 for group interaction). During treatment, 25 patients developed Grade ≥3 CVAEs. Low baseline FMD (HR 2.57 lowest vs. higher tertiles, 95% CI 1.081-6.1) was an independent predictor of CVAEs. During treatment, an acute FMD decrease >40% at the end of first cycle was also independently associated with CVAEs (HR = 3.91, 95% CI 1.29-11.83). Kd treatment impairs endothelial function which is associated with PrA inhibition and recovery. Both pre- and posttreatment FMD predicted CFZ-related CVAEs supporting its role as a possible cardiovascular toxicity biomarker.

Pilot Study: Quantitative Photoacoustic Evaluation of Peripheral Vascular Dynamics Induced by Carfilzomib In Vivo

Carfilzomib is mainly used to treat multiple myeloma. Several side effects have been reported in patients treated with carfilzomib, especially those associated with cardiovascular events, such as hypertension, congestive heart failure, and coronary artery disease. However, the side effects, especially the manifestation of cardiovascular events through capillaries, have not been fully investigated. Here, we performed a pilot experiment to monitor peripheral vascular dynamics in a mouse ear under the effects of carfilzomib using a quantitative photoacoustic vascular evaluation method. Before and after injecting the carfilzomib, bortezomib, and PBS solutions, we acquired high-resolution three-dimensional PAM data of the peripheral vasculature of the mouse ear during each experiment for 10 h. Then, the PAM maximum amplitude projection (MAP) images and five quantitative vascular parameters, i.e., photoacoustic (PA) signal, diameter, density, length fraction, and fractal dimension, were estimated. Quantitative results showed that carfilzomib induces a strong effect on the peripheral vascular system through a significant increase in all vascular parameters up to 50%, especially during the first 30 min after injection. Meanwhile, bortezomib and PBS do not have much impact on the peripheral vascular system. This pilot study verified PAM as a comprehensive method to investigate peripheral vasculature, along with the effects of carfilzomib. Therefore, we expect that PAM may be useful to predict cardiovascular events caused by carfilzomib.

Optimizing Cardiovascular Health in Patients With Cancer: A Practical Review of Risk Assessment, Monitoring, and Prevention of Cancer Treatment-Related Cardiovascular Toxicity

Advances in cancer screening and improved treatment approaches have led to an increase in survivorship and, consequently, recognition of an association between cancer treatments and the development of cardiovascular complications. In addition, as the population becomes proportionally older, comorbid cardiovascular risk factors are more prevalent in the population and compound the risk of developing cancer treatment-related cardiovascular toxicity. Cardio-oncology has emerged as a new subspecialty of medicine that provides a multidisciplinary approach, bringing together oncologists, cardiologists, and allied health care providers who are tasked with optimizing the cardiovascular health of patients exposed to potentially cardiotoxic cancer therapy. Using a case-based approach, practical advice on how to identify, monitor, and treat patients with cancer who are at risk for developing cancer treatment-related cardiovascular dysfunction is discussed. Cardiovascular risk factors (e.g., age, hypertension, diabetes) and cancer therapies (chemotherapy, targeted therapy, radiation) associated with cardiovascular toxicity are presented. Current cardiac monitoring strategies such as two- and three-dimensional echocardiography, cardiac MRI, and biomarkers (troponin and brain natriuretic peptide [BNP]) are discussed. Last, the current literature on pharmacologic (e.g., angiotensin-converting enzyme inhibitors, β-blockers, statins) and lifestyle (diet and exercise) strategies to mitigate cardiovascular toxicity during and following completion of cancer therapy are reviewed.

Metformin decreased myocardial fibrosis and apoptosis in hyperhomocysteinemia -induced cardiac hypertrophy

BACKGROUND

Hyperhomocysteinemia (HHcy) is one of the major risk factors of cardiovascular diseases. Metformin acts as a cardioprotective role in several cardiovascular diseases, including ischemia/reperfusion, atherosclerosis, and myocardial infarction. However, whether metformin protects against HHcy-induced cardiac hypertrophy is unclear.

METHODS AND RESULTS

HHcy model was established in C57BL/6 mice with high L-methionine (L-MET) diet for 12 weeks. AC16 cells were exposed to homocysteine (Hcy) and then intervened with different concentrations of metformin in in vitro studies. The results showed that HHcy was able to induce cardiac hypertrophy, and metformin could abrogate this effect. HHcy increased the fibrosis area and induced apoptosis in the myocardium, whereas metformin could reverse the detrimental effects above. TUNEL assay showed that metformin was able to decrease Hcy-induced apoptosis in AC16 cells. Moreover, western blotting assay revealed that metformin could decrease Hcy-induced expression of Bax and cleaved caspase3, and increase the expression of Bcl-2.

CONCLUSIONS

This study demonstrates that metformin is able to attenuate HHcy-induced cardiac hypertrophy by decreasing myocardial fibrosis and apoptosis.

Levosimendan prevents doxorubicin-induced cardiotoxicity in time- and dose-dependent manner: implications for inotropy

AIMS

Levosimendan (LEVO) a clinically-used inodilator, exerts multifaceted cardioprotective effects. Case-studies indicate protection against doxorubicin (DXR)-induced cardiotoxicity, but this effect remains obscure. We investigated the effect and mechanism of different regimens of levosimendan on sub-chronic and chronic doxorubicin cardiotoxicity.

METHODS AND RESULTS

Based on preliminary in vivo experiments, rats serving as a sub-chronic model of doxorubicin-cardiotoxicity and were divided into: Control (N/S-0.9%), DXR (18 mg/kg-cumulative), DXR+LEVO (LEVO, 24 μg/kg-cumulative), and DXR+LEVO (acute) (LEVO, 24 μg/kg-bolus) for 14 days. Protein kinase-B (Akt), endothelial nitric oxide synthase (eNOS), and protein kinase-A and G (PKA/PKG) pathways emerged as contributors to the cardioprotection, converging onto phospholamban (PLN). To verify the contribution of PLN, phospholamban knockout (PLN-/-) mice were assigned to PLN-/-/Control (N/S-0.9%), PLN-/-/DXR (18 mg/kg), and PLN-/-/DXR+LEVO (ac) for 14 days. Furthermore, female breast cancer-bearing (BC) mice were divided into: Control (normal saline 0.9%, N/S 0.9%), DXR (18 mg/kg), LEVO, and DXR+LEVO (LEVO, 24 μg/kg-bolus) for 28 days. Echocardiography was performed in all protocols. To elucidate levosimendan's cardioprotective mechanism, primary cardiomyocytes were treated with doxorubicin or/and levosimendan and with N omega-nitro-L-arginine methyl ester (L-NAME), DT-2, and H-89 (eNOS, PKG, and PKA inhibitors, respectively); cardiomyocyte-toxicity was assessed. Single bolus administration of levosimendan abrogated DXR-induced cardiotoxicity and activated Akt/eNOS and cAMP-PKA/cGMP-PKG/PLN pathways but failed to exert cardioprotection in PLN-/- mice. Levosimendan's cardioprotection was also evident in the BC model. Finally, in vitro PKA inhibition abrogated levosimendan-mediated cardioprotection, indicating that its cardioprotection is cAMP-PKA dependent, while levosimendan preponderated over milrinone and dobutamine, by ameliorating calcium overload.

CONCLUSION

Single dose levosimendan prevented doxorubicin cardiotoxicity through a cAMP-PKA-PLN pathway, highlighting the role of inotropy in doxorubicin cardiotoxicity.

Carfilzomib induced cardiotoxicity in a multiple myeloma patient

Proteasome inhibitors such as carfilzomib are indicated in multiple myeloma patients showing relapse and/or refractoriness of clonal activity. However, this therapy has been associated with a significant incidence of cardiotoxicity, especially in patients with known cardiovascular risk factors. Here we report a case of a 60-year-old woman with multiple myeloma, who developed severe congestive heart failure with positive myocardial injury biomarkers together with impaired LVEF and GLS, after treatment with carfilzomib. Therefore, chemotherapeutic drug was discontinued and neurohormonal blocking and diuretic therapy was started resulting in amelioration of symptoms, without changes in LVEF but with significant GLS improvement. Although high-grade cardiotoxicity is relatively rare in patients with non previous cardiac risk factors, it was a predictable side effect of carfilzomib use. Recognition of this syndrome is critical to instauration of appropriate therapy and prevention of morbimortality.

Proteasome inhibition for the treatment of glioblastoma

INTRODUCTION

Glioblastoma is a primary brain tumor with a poor prognosis despite multimodal therapy including surgery, radiotherapy and alkylating chemotherapy. Novel therapeutic options are therefore urgently needed; however, there have been various drug failures in late-stage clinical development. The proteasome represents a key target for anti-cancer therapy as successfully shown in multiple myeloma and other hematologic malignancies.

AREAS COVERED

This review article summarizes the preclinical and clinical development of proteasome inhibitors in the context of glioblastoma.

EXPERT OPINION

Early clinical trials with bortezomib ended with disappointing results, possibly because this agent does not cross the blood-brain barrier. In contrast to bortezomib and other proteasome inhibitors, marizomib is a novel drug that displays strong inhibitory properties on all enzymatic subunits of the proteasome and, most importantly, crosses the blood-brain barrier, making it a potentially very active novel agent against intrinsic brain tumors. While preclinical studies have demonstrated significant anti-glioma activity, its clinical benefit has yet to be proven. Exploiting the biological effects of proteasome inhibitors in combination with other therapeutic strategies may represent a key next step in their clinical development.

Cancer Therapeutics-Related Cardiac Dysfunction - Insights From Bench and Bedside of Onco-Cardiology

Improvements in the long-term survival of cancer patients have led to growing awareness of the clinical importance of cancer therapeutics-related cardiac dysfunction (CTRCD), which can have a considerable effect on the prognosis and quality of life of cancer patients and survivors. Under such circumstances, onco-cardiology/cardio-oncology has emerged as a new discipline, with the aim of best managing cardiovascular complications, including CTRCD. Despite the recent accumulation of epidemiological and clinical information regarding CTRCD, the molecular mechanisms underlying the pathogenesis of CTRCD by individual drugs remain to be determined. To achieve the goal of preventing cardiovascular complications in cancer patients and survivors, it is important to elucidate the pathogenic mechanisms and to establish diagnostic strategies with risk prediction and mechanism- and evidence-based therapies against CTRCD.

Investigating the Vascular Toxicity Outcomes of the Irreversible Proteasome Inhibitor Carfilzomib

Background: Carfilzomib’s (Cfz) adverse events in myeloma patients include cardiovascular toxicity. Since carfilzomib’s vascular effects are elusive, we investigated the vascular outcomes of carfilzomib and metformin (Met) coadministration. Methods: Mice received: (i) saline; (ii) Cfz; (iii) Met; (iv) Cfz+Met for two consecutive (acute) or six alternate days (subacute protocol). Leucocyte-derived reactive oxygen species (ROS) and serum NO_x levels were determined and aortas underwent vascular and molecular analyses. Mechanistic experiments were recapitulated in aged mice who received similar treatment to young animals. Primary murine (prmVSMCs) and aged human aortic smooth muscle cells (HAoSMCs) underwent Cfz, Met and Cfz+Met treatment and viability, metabolic flux and p53-LC3-B expression were measured. Experiments were recapitulated in AngII, CoCl₂ and high-glucose stimulated HAoSMCs. Results: Acutely, carfilzomib alone led to vascular hypo-contraction and increased ROS release. Subacutely, carfilzomib increased ROS release without vascular manifestations. Cfz+Met increased PGF2α-vasoconstriction and LC3-B-dependent autophagy in both young and aged mice. In vitro, Cfz+Met led to cytotoxicity and autophagy, while Met and Cfz+Met shifted cellular metabolism. Conclusion: Carfilzomib induces a transient vascular impairment and oxidative burst. Cfz+Met increased vascular contractility and synergistically induced autophagy in all settings. Therefore, carfilzomib cannot be accredited for a permanent vascular dysfunction, while Cfz+Met exert vasoprotective potency.

Oncocardiology: new challenges, new opportunities

Patients with cancer are at a higher risk of cardiovascular disease, which contributes to significant morbidity and mortality. The rapid progress in the field of oncological treatments has led to a steady increase in long-term cancer survivors. Care for cardiovascular complications is therefore becoming increasingly important. In addition, the establishment of new oncological therapies has resulted in the identification of previously unknown cardiovascular side effects. Oncocardiology aims to detect and treat cardiovascular diseases associated with cancer and cancer therapy. Continuous scientific, clinical, and structural developments are necessary as the basis for the best care of the growing number of affected patients. This review summarizes current developments in the field of oncocardiology with regard to advances in cancer therapy and challenges in clinical oncocardiology work. Cardiovascular side effects by targeted cancer therapies are characterized and recent advances in the field of cardiovascular diagnostics are outlined. Developments to better integrate oncocardiology into the medical care system and perspectives for modern, patient-oriented care are shown. In light of the coronavirus disease 2019 (COVID-19) pandemic, current challenges and opportunities are highlighted. The relevance of profitable further advances in oncocardiology including standardized guidelines and educational programs is delineated as a mandatory requirement for the successful development of oncocardiology.

Treatment and disease-related complications in multiple myeloma: Implications for survivorship

New treatments have transformed multiple myeloma into a chronic disease. Hence, optimal management of treatment and disease-related complications remains a critical component of survivorship care. Survivorship care model in cancers requiring a fixed-duration therapy may not be applicable to myeloma, since patients are exposed to multiple lines of continuous therapy along the disease trajectory. The two most common therapy-related causes of death, which require special consideration, are infection and second cancers. Identifying patients at a high risk of toxicities will facilitate individualized treatment selection and designing clinical trials for protective strategies targeting those patients. For example, prophylactic antibiotic or immunoglobulin replacement can be tested for primary prevention of infections in high-risk patients. Long-term follow up of ongoing trials and epidemiologic data will help identify the nature and trajectory of rare toxicities with a long latency, such as secondary cancers. Patients who are frail, have persistent renal insufficiency, and refractory to multiple lines of therapy need special attention regarding treatment toxicity and quality of life. In this review, we discuss the incidence, risk-factors, and management of treatment and disease-related complications in myeloma, discuss knowledge gaps and research priorities in this area, and propose a survivorship care model to improve health-care delivery to a growing pool of myeloma survivors.

Hesperidin ameliorates signs of the metabolic syndrome and cardiac dysfunction via IRS/Akt/GLUT4 signaling pathway in a rat model of diet-induced metabolic syndrome

BACKGROUND

Hesperidin has been reported to have biological activities such as antihypertensive, hypoglycemic, and antioxidant effects. This study investigated whether hesperidin could improve signs of the metabolic syndrome and cardiac function in a high-fat diet (HFD) induced metabolic syndrome (MS) in rats.

METHODS

Male Sprague-Dawley rats were fed HFD and 15% fructose for 16 weeks and treated with hesperidin (15 or 30 mg/kg, based on signs of MS from a preliminary study) or metformin, a positive control agent, (100 mg/kg) for the final four weeks. Cardiac function, blood pressure, fasting blood glucose, oral glucose tolerance, serum insulin, and lipid profiles were measured. Histomorphometrics of left ventricles, epidydimal fat pads and liver were evaluated. Expressions of phosphorylate insulin receptor substrate1(p-IRS1), p-Akt and GLUT4 in cardiac tissue were determined.

RESULTS

Hesperidin and metformin attenuated MS in HFD rats (p < 0.05). The accumulation of visceral fat pads and fatty liver associated with increases in liver lipid contents and liver enzymes were found in MS rats that were alleviated in hesperidin or metformin-treated groups (p < 0.05). Hesperidin and metformin improved cardiac dysfunction and hypertrophy observed in MS rats (p < 0.05). Restoration of the insulin signaling pathway, IRS/Akt/GLUT4 protein expression, was demonstrated in hesperidin and metformin-treated groups (p < 0.05). Hesperidin (30 mg/kg) was more effective than the lower dose.

CONCLUSION

Hesperidin was effective in reducing signs of MS and alterations of LV hypertrophy and function. These beneficial effects on the heart were associated with the restoration of the cardiac insulin signaling pathway in MS rats.

Proteasome Inhibitors for the Treatment of Multiple Myeloma

Use of proteasome inhibitors (PIs) has been the therapeutic backbone of myeloma treatment over the past decade. Many PIs are being developed and evaluated in the preclinical and clinical setting. The first-in-class PI, bortezomib, was approved by the US food and drug administration in 2003. Carfilzomib is a next-generation PI, which selectively and irreversibly inhibits proteasome enzymatic activities in a dose-dependent manner. Ixazomib was the first oral PI to be developed and has a robust efficacy and favorable safety profile in patients with multiple myeloma. These PIs, together with other agents, including alkylators, immunomodulatory drugs, and monoclonal antibodies, have been incorporated into several regimens. This review summarizes the biological effects and the results of clinical trials investigating PI-based combination regimens and novel investigational inhibitors and discusses the future perspective in the treatment of multiple myeloma.

High Effectiveness in Actions of Carfilzomib on Delayed-Rectifier K+ Current and on Spontaneous Action Potentials

Carfilzomib (CFZ, Kyprolis®) is widely recognized as an irreversible inhibitor of proteasome activity; however, its actions on ion currents in electrically excitable cells are largely unresolved. The possible actions of CFZ on ionic currents and membrane potential in pituitary GH3, A7r5 vascular smooth muscle, and heart-derived H9c2 cells were extensively investigated in this study. The presence of CFZ suppressed the amplitude of delayed-rectifier K+ current (I K(DR)) in a time-, state-, and concentration-dependent manner in pituitary GH3 cells. Based on minimal reaction scheme, the value of dissociation constant for CFZ-induced open-channel block of I K(DR) in these cells was 0.33 µM, which is similar to the IC50 value (0.32 µM) used for its efficacy on inhibition of I K(DR) amplitude. Recovery from I K(DR) block by CFZ (0.3 µM and 1 µM) could be well fitted by single exponential with 447 and 645 ms, respectively. The M-type K+ current, another type of K+ current elicited by low-threshold potential, was slightly suppressed by CFZ (1 µM). Under current-clamp condition, addition of CFZ depolarized GH3 cells, broadened the duration of action potentials as well as raised the firing frequency. In A7r5 vascular smooth muscle cells or H9c2 cardiac cells, the CFZ-induced inhibition of I K(DR) remained efficacious. Therefore, our study led us to reflect that CFZ or other structurally similar compounds should somehow act on the activity of membrane KV channels through which they influence the functional activities in different types of electrically excitable cells such as endocrine, neuroendocrine cells, smooth muscle cells, or heart cells, if similar in vivo findings occur.

Prevention, monitoring and treatment of cardiovascular adverse events in myeloma patients receiving carfilzomib A consensus paper by the European Myeloma Network and the Italian Society of Arterial Hypertension

BACKGROUND

The novel proteasome inhibitor carfilzomib alone or in combination with other agents is already one of the standard therapies for relapsed and/or refractory multiple myeloma (MM) patients and produces impressive response rates in newly diagnosed MM as well. However, carfilzomib-related cardiovascular adverse events (CVAEs) - including hypertension (all grades: 12.2%; grade ≥3: 4.3%), heart failure (all grades: 4.1%; grade ≥3: 2.5%) and ischemic heart disease (all grades: 1.8%; grade ≥3: 0.8%) - may lead to treatment suspensions. At present, there are neither prospective studies nor expert consensus on the prevention, monitoring and treatment of CVAEs in myeloma patients treated with carfilzomib.

METHODS

An expert panel of the European Myeloma Network in collaboration with the Italian Society of Arterial Hypertension and with the endorsement of the European Hematology Association aimed to provide recommendations to support health professionals in selecting the best management strategies for patients, considering the impact on outcome and the risk-benefit ratio of diagnostic and therapeutic tools, thereby achieving myeloma response with novel combination approaches whilst preventing CVAEs.

RESULTS

Patients scheduled to receive carfilzomib need a careful cardiovascular evaluation before treatment and an accurate follow-up during treatment.

CONCLUSIONS

A detailed clinical assessment before starting carfilzomib treatment is essential to identify patients at risk for CVAEs, and accurate monitoring of blood pressure and of early signs and symptoms suggestive of cardiac dysfunction remains pivotal to safely administer carfilzomib without treatment interruptions or dose reductions.

The First Autopsy Case of Fatal Acute Cardiac Failure after Administration of Carfilzomib in a Patient with Multiple Myeloma

Carfilzomib (CFZ) improves progression-free survival for patients with relapsed or refractory multiple myeloma (MM) but has shown higher frequency of cardiovascular adverse events (CVAEs) than other proteasome inhibitors. We report the first autopsy case of acute death from cardiac failure shortly after administration of carfilzomib. A 74-year-old female was diagnosed with IgA MM after a 2-year period of smoldering MM. She was refractory to both bortezomib plus dexamethasone and lenalidomide plus dexamethasone therapies, so she subsequently received CFZ in combination with lenalidomide and dexamethasone. The day after the start of the therapy, she complained of severe dyspnea with a significant decline in left ventricular ejection fraction. Her acute cardiac failure rapidly progressed, and she died on day 7 of the start of CFZ. The autopsy showed invasion of inflammatory cells between the myocardial cells and very little myocardial necrosis. There was no obvious thrombus in the coronary artery of the heart, and no infarction or amyloid deposition was observed in the myocardium. Pathological findings of hypersensitivity myocarditis, a drug-induced cardiomyopathy, appeared to agree with this case except for absence of an eosinophilic infiltration of the myocardium. A CFZ-induced CVAE is generally considered reversible. However, rapidly progressing fatal heart failure like in our case is rare. To characterize CFZ-associated CVAE, further case collection is needed.

Investigating and re-evaluating the role of glycogen synthase kinase 3 beta kinase as a molecular target for cardioprotection by using novel pharmacological inhibitors

AIMS

Glycogen synthase kinase 3 beta (GSK3β) link with the mitochondrial Permeability Transition Pore (mPTP) in cardioprotection is debated. We investigated the role of GSK3β in ischaemia (I)/reperfusion (R) injury using pharmacological tools.

METHODS AND RESULTS

Infarct size using the GSK3β inhibitor BIO (6-bromoindirubin-3'-oxime) and several novel analogues (MLS2776-MLS2779) was determined in anaesthetized rabbits and mice. In myocardial tissue GSK3β inhibition and the specificity of the compounds was tested. The mechanism of protection focused on autophagy-related proteins. GSK3β localization was determined in subsarcolemmal (SSM) and interfibrillar mitochondria (IFM) isolated from Langendorff-perfused murine hearts (30'I/10'R or normoxic conditions). Calcium retention capacity (CRC) was determined in mitochondria after administration of the inhibitors in mice and in vitro. The effects of the inhibitors on mitochondrial respiration, reactive oxygen species (ROS) formation, ATP production, or hydrolysis were measured in SSM at baseline. Cyclosporine A (CsA) was co-administered with the inhibitors to address putative additive cardioprotective effects. Rabbits and mice treated with MLS compounds had smaller infarct size compared with control. In rabbits, MLS2776 and MLS2778 possessed greater infarct-sparing effects than BIO. GSK3β inhibition was confirmed at the 10th min and 2 h of reperfusion, while up-regulation of autophagy-related proteins was evident at late reperfusion. The mitochondrial amount of GSK3β was similar in normoxic SSM and IFM and was not altered by I/R. The inhibitors did not affect CRC or respiration, ROS and ATP production/hydrolysis at baseline. The co-administration of CsA ensured that cardioprotection was CypD-independent.

CONCLUSION

Pharmacological inhibition of GSK3β attenuates infarct size beyond mPTP inhibition.