Mechanism of cardiovascular toxicity by proteasome inhibitors: New paradigm derived from clinical and pre-clinical evidence

Genome-wide analysis in PC6 electroacupuncture to ameliorate carfilzomib-induced cardiotoxicity in mice

Carfilzomib (CFZ), a proteasome inhibitor commonly used in the treatment of multiple myeloma (MM), exhibits limited clinical application due to its cardiotoxicity. In our study, electroacupuncture (EA) at Neiguan acupoint (PC6) effectively reversed CFZ-induced reduction in ejection fraction (EF) and fractional shortening (FS), demonstrating great potential effect for heart protection. Through comparative analysis of the transcriptome profile from heart samples of mice treated with DMSO control, CFZ injection, and EA stimulation, we identified a total of 770 differentially expressed genes (DEGs) in CFZ (vs. Control) group and 329 DEGs in EA (vs. CFZ) group. Specifically, CFZ (vs. Control) group exhibited 65 up-regulated DEGs and 705 down-regulated DEGs, while EA (vs. CFZ) group displayed 251 up-regulated DEGs and 78 down-regulated DEGs. Metascape analysis revealed that among these treatment groups, there were 137 co-expressed DEGs remarkably enriched in skeletal system development, cellular response to growth factor stimulus, negative regulation of Wnt signaling pathway, and muscle contraction. The expression patterns of miR-8114, Myl4, Col1a1, Tmem163, Myl7, Sln, and Fxyd3, which belong to the top 30 DEGs, were verified by quantitative real-time PCR (RT-qPCR). In summary, this study firstly discloses novel insights into the regulatory mechanisms underlying PC6-based EA therapy against CFZ-induced cardiotoxicity, potentially serving as a theoretical foundation for further clinical applications.

Cardiovascular Toxicity of Proteasome Inhibitors in Multiple Myeloma Therapy

The treatment for multiple myeloma has advanced significantly over the past few decades. Proteasome inhibitors have become the cornerstone of the treatment of multiple myeloma. However, proteasome inhibitors have shown cardiovascular complications such as hypertension, pulmonary hypertension, heart failure, arrhythmias, ischaemic heart disease and thromboembolism. Detection, monitoring and management of proteasome inhibitor-related cardiovascular toxicity are essential to improve clinical outcomes for patients. Proposed mechanisms of proteasome inhibitor-related cardiovascular toxicity are apoptosis, prolonged inhibition of the ubiquitin-proteasome system, accumulation of improperly folded proteins within cardiomyocytes and higher protein phosphatase 2A activity. To better understand the mechanisms underlying cardiotoxicity, further in vitro and in vivo experiments are required to investigate these hypotheses. Combined use of metformin or angiotensin II receptor blockers with the proteasome inhibitor, carfilzomib, showed an emerging role as a prophylactic therapy because they can preserve heart function in multiple myeloma patients. Metformin is expected to be an effective therapeutic intervention for the management of carfilzomib-induced cardiotoxicity. There has been evidence that three compounds, apremilast, rutin, and dexrazoxane, can reverse carfilzomib-induced cardiotoxicity in rats. The future transition from animal experiments to clinical trials is worth waiting for.

Cancer Therapy-Related Hypertension: A Scientific Statement From the American Heart Association

Contemporary anticancer drugs have significantly improved cancer survival at the expense of cardiovascular toxicities, including heart disease, thromboembolic disease, and hypertension. One of the most common side effects of these drugs is hypertension, especially in patients treated with vascular endothelial growth factor inhibitors, as well as tyrosine kinase inhibitors and proteasome inhibitors. Adjunctive therapy, including corticosteroids, calcineurin inhibitors, and nonsteroidal anti-inflammatories, as well as anti-androgen hormone therapy for prostate cancer, may further increase blood pressure in these patients. Cancer therapy-induced hypertension is often dose limiting, increases cardiovascular mortality in cancer survivors, and is usually reversible after interruption or discontinuation of treatment. The exact molecular mechanisms underlying hypertension are unclear, but recent discoveries indicate an important role for reduced nitric oxide generation, oxidative stress, endothelin-1, prostaglandins, endothelial dysfunction, increased sympathetic outflow, and microvascular rarefaction. In addition, genetic polymorphisms in vascular endothelial growth factor receptors are implicated in vascular endothelial growth factor inhibitor-induced hypertension. Diagnosis, management, and follow-up of cancer therapy-induced hypertension follow national hypertension guidelines because evidence-based clinical trials specifically addressing patients who develop hypertension as a result of cancer therapy are currently lacking. Rigorous baseline assessment of patients before therapy is started requires particular emphasis on assessing and treating cardiovascular risk factors. Hypertension management follows guidelines for the general population, although special attention should be given to rebound hypotension after termination of cancer therapy. Management of these complex patients requires collaborative care involving oncologists, cardiologists, hypertension specialists, primary care professionals, and pharmacists to ensure the optimal therapeutic effect from cancer treatment while minimizing competing cardiovascular toxicities.

Regulation of progesterone receptor expression in endometriosis, endometrial cancer, and breast cancer by estrogen, polymorphisms, transcription factors, epigenetic alterations, and ubiquitin-proteasome system

The uterus and breasts are hormone-responsive tissues. Progesterone and estradiol regulate gonadotropin secretion, prepare the endometrium for implantation, maintain pregnancy, and regulate the differentiation of breast tissue. Dysregulation of these hormones causes endometriosis, endometrial cancer, and breast cancer, damaging the physical and mental health of women. Emerging evidence has shown that progesterone resistance or elevated progesterone activity is the primary hormonal substrate of these diseases. Since progesterone acts through its specific nuclear receptor, the abnormal expression of the progesterone receptor (PR) dysregulates progesterone function. This review discusses the regulatory mechanisms of PR expression in patients with endometriosis, and endometrial or breast cancer, including estrogen, polymorphisms, transcription factors, epigenetics, and the ubiquitin-proteasome system. (1) Estrogen promotes the expression of PRA (a PR isoform) mRNA and protein through the interaction of estrogen receptors (ERs) and Sp1 with half-ERE/Sp1 binding sites. ERs also affect the binding of Sp1 and Sp1 sites to promote the expression of PRB (another PR isoform)(2) PR polymorphisms, mainly PROGINS and + 331 G/A polymorphism, regulate PR expression by affecting DNA methylation and transcription factor binding. (3) The influence of epigenetic alterations on PR expression occurs through DNA methylation, histone modification, and microRNA. (4) As one of the main protein degradation pathways in vivo, the ubiquitin-proteasome system (UPS) regulates PR expression by participating in protein degradation. These mechanisms may provide new molecular targets for diagnosing and treating endometriosis, endometrial, and breast cancer.

Carfilzomib-Based Regimen and Cardiotoxicity in Multiple Myeloma: Incidence of Cardiovascular Events and Organ Damage in Carfilzomib-Dexamethasone versus Carfilzomib-Lenalidomide-Dexamethasone. A Real-Life Prospective Study

Carfilzomib-mediated cardiotoxicity in multiple myeloma (MM) is a well-established adverse effect, however limited data are available on the comparison of cardiovascular complications in patients treated with Carfilzomib-dexamethasone (target dose of K 56 mg/m²) versus Carfilzomib-lenalidomide-dexamethasone (target dose of K 27 mg/m²) beyond controlled trials. A total of 109 patients were enrolled, 47 (43%) received Kd and 62 (57%) KRd. They then underwent a baseline and follow-up evaluation including trans-thoracic echocardiography and arterial stiffness estimation. All types of cardiovascular and hypertensive events occurred more frequently in the Kd group compared with the KRd (59% vs. 40% and 55% vs. 35.5% patients, respectively, p ≤ 0.05), with higher incidence of hypertensive. The time of onset of any type of CVAE, and of major and hypertensive events was shorter in the Kd regimen (p ≤ 0.05). At follow-up, Kd patients more frequently developed signs of cardiac (decline of global longitudinal strain) and vascular organ damage (rise of pulse wave velocity), as compared with KRd. Despite the older age, longer history of MM and longer period of pre-treatment of Kd patients, these factors did not increase the probability of incidence for all types of cardiovascular events at multivariate analysis (p > 0.05). In conclusion, the Kd regimen showed greater cardiovascular toxicity and earlier onset of events with respect to KRd. Thus, a closer and thorough follow-up should be considered.

Peripheral Neuropathy During Concomitant Administration of Proteasome Inhibitors and Factor Xa Inhibitors: Identifying the Likelihood of Drug-Drug Interactions

Backgrounds: Proteasome inhibitors (PI) cause toxic peripheral neuropathy (PN), which is one of the dose-limiting adverse events of these treatments. Recent preclinical studies find that factor Xa inhibitor (FXaI), rivaroxaban, promotes PN in animals receiving oxaliplatin. Cancer patients can receive combined therapy of PI and FXaI. This study aimed to identify and characterize the interaction signals for the concomitant use of PI and FXaI resulting in PN.

Methods: Reports from the United States FDA Adverse Event Reporting System (FAERS) were extracted from the first quarter of 2004 to the first quarter of 2020 for analysis. The Standardized Medical Dictionary for Regulatory Activities (MedDRA) query was used to identify PN cases. We conducted an initial disproportionality investigation to detect PN adverse event signals associated with the combined use of PI and FXaI by estimating a reporting odds ratio (ROR) with a 95% confidence interval (CI). The adjusted RORs were then analyzed by logistic regression analysis (adjusting for age, gender, and reporting year), and additive/multiplicative models were performed to further confirm the findings. Additionally, subset data analysis was performed on the basis of a single drug of PI and FXaI.

Results: A total of 159,317 adverse event reports (including 2,822 PN reports) were included. The combined use of PI and FXaI was associated with a higher reporting of PN (RORadj = 7.890, 95%CI, 5.321–11.698). The result remained significant based on additive/multiplicative methods. The observed association was consistent in the analysis restricted to all specific PI agents (bortezomib and ixazomib) and FXaI (rivaroxaban), except apixaban.

Conclusion: Analysis of FAERS data identified reporting associations of PN in the combined use of PI and FXaI, suggesting the need for more robust preclinical and clinical studies to elucidate the relationship.

Cardiotoxicity as an adverse effect of immunomodulatory drugs and proteasome inhibitors in multiple myeloma: A network meta-analysis of randomized clinical trials

We aim to determine the cumulative and comparative risk of cardiovascular events associated with different Immunomodulatory Drugs (iMiDs) and Proteasome Inhibitor (PIs) in Multiple Myeloma (MM) patients through pairwise and network meta-analysis. Electronic searches were conducted using Ovid MEDLINE, EMBASE, CINAHL, Web of Science, and Clinical Trial Registry (Clinical Trials.gov) up to May 2021. Phase 3 randomized clinical trials (RCTs) reporting cardiotoxicity in MM patients (newly diagnoses and/or relapsed) treated with iMiD and/or PI. Studies, where iMiD or PI was used alongside the chemotherapy versus placebo or no additional drugs (control) in the other arm were included. The primary outcome was the presence of cardiotoxicity after follow-up. Pairwise meta-analysis and network meta-analysis were performed using the frequentist's approach to estimate the odds ratio (OR). Twenty RCTs with 10,373 MM patients were included in this analysis. Eleven studies compared iMiDs with control, seven studies compared PIs with control, and two studies compared bortezomib against carfilzomib. CTACE high-grade (≥grade 3) cardiotoxic events were increased with iMiDs compared to their control counterpart (OR 2.05; 95% CI 1.30-3.26). Similar high-grade cardiotoxicity was also noted more frequently with PI use when compared to the control group (OR 1.67; 95% CI 1.17-2.40). Among the PIs, carfilzomib was associated with a maximum risk of cardiotoxicity (OR 2.68; 95% CI 1.63-4.40). There was no evidence of publication bias among studies. iMiDs and PIs, particularly carfilzomib, appear to be associated with increased risk of high-grade cardiovascular events in MM patients.

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.

Cardiovascular Toxicity of Carfilzomib: The Real-World Evidence Based on the Adverse Event Reporting System Database of the FDA, the United States

Background: Carfilzomib, an effective proteasome inhibitor agent for the therapy of relapsed and refractory multiple myeloma, has been related to a significant number of cardiovascular events. However, patterns of cardiovascular complications associated with this agent remain poorly characterized in real-world settings. Objective: To gain further insight into the frequency, spectrum, clinical features, timing, and outcomes of carfilzomib-related cardiovascular toxicities. Methods: This disproportionality (case/non-case) study was conducted leveraging records from FAERS database from 2014 to 2019. Cardiovascular events were defined and broadly categorized eight entities using narrow version of the Standardized MedDRA Queries (SMQs). Reporting odds ratios (ROR) and information component (IC) were calculated to measure disproportionality. Additionally, statistical shrinkage was applied to reduce false-positive signals. Results: The final number of records involved was 28,479,963, with 3,370 records submitted for carfilzomib related cardiovascular events. Significant disproportionality association between carfilzomib administration and cardiovascular events was captured (IC025/ROR025 = 0.85/1.95) when exploring in the entire database. Upon further analysis, all eight broad categories of cardiovascular toxicities were disproportionately associated with carfilzomib with varying frequencies, time-to-onset, and severities. Cardiomyopathy-related complications (N = 1,301, 38.61%), embolic and thrombotic events (N = 821, 24.36%), and cardiac failure (N = 765, 22.70%) largely comprised the reported problems. Notably, the strongest signal was detected for cardiac failure (IC025/ROR025 = 1.33/2.59), followed by pulmonary hypertension (IC025/ROR025 = 1.19/2.34). Median onset time of cardiovascular events was 41days (Q1-Q3: 9-114 days), with the shortest median time being 16 days (Q1-Q3: 4-85 days) for ischemic heart disease, with the longest time being 68 days (Q1-Q3: 21-139 days) for embolic and thrombotic events. Torsade de pointes/QT prolongation was identified as a new complication (IC025/ROR025 = 0.33/1.29) and was particularly noteworthy for highest death proportion (44.11%). Conclusions: Treatment with carfilzomib can lead to severe and versatile cardiovascular events. Early and intensive monitoring is important, particularly in the first 3 months after carfilzomib initiation. Maximizing the benefit while reducing potential cardiovascular harms of carfilzomib should become a priority.

Activity of immunoproteasome inhibitor ONX-0914 in acute lymphoblastic leukemia expressing MLL-AF4 fusion protein

Proteasome inhibitors bortezomib and carfilzomib are approved for the treatment of multiple myeloma and mantle cell lymphoma and have demonstrated clinical efficacy for the treatment of acute lymphoblastic leukemia (ALL). The t(4;11)(q21;q23) chromosomal translocation that leads to the expression of MLL-AF4 fusion protein and confers a poor prognosis, is the major cause of infant ALL. This translocation sensitizes tumor cells to proteasome inhibitors, but toxicities of bortezomib and carfilzomib may limit their use in pediatric patients. Many of these toxicities are caused by on-target inhibition of proteasomes in non-lymphoid tissues (e.g., heart muscle, gut, testicles). We found that MLL-AF4 cells express high levels of lymphoid tissue-specific immunoproteasomes and are sensitive to pharmacologically relevant concentrations of specific immunoproteasome inhibitor ONX-0914, even in the presence of stromal cells. Inhibition of multiple active sites of the immunoproteasomes was required to achieve cytotoxicity against ALL. ONX-0914, an inhibitor of LMP7 (ß5i) and LMP2 (ß1i) sites of the immunoproteasome, and LU-102, inhibitor of proteasome ß2 sites, exhibited synergistic cytotoxicity. Treatment with ONX-0914 significantly delayed the growth of orthotopic ALL xenograft tumors in mice. T-cell ALL lines were also sensitive to pharmacologically relevant concentrations of ONX-0914. This study provides a strong rationale for testing clinical stage immunoproteasome inhibitors KZ-616 and M3258 in ALL.

Cancer and atrial fibrillation: Epidemiology, mechanisms, and anticoagulation treatment

Cancer patients are at an increased risk of developing atrial fibrillation (AF) and thrombosis. However, the management of anticoagulation in patients with both diseases may be challenging, and data on these patients are lacking. We summarize the current evidence on the incidence and prevalence of cancer in AF and vice versa and provide some practical considerations on the management of oral anticoagulation in specific clinical situations. Low-molecular weight heparins are not approved for thromboprophylaxis in AF, and management of warfarin can be difficult. The use of direct oral anticoagulants may be particularly attractive for their rapid onset/offset action and lower bleeding risk.

Effects of Carfilzomib Therapy on Left Ventricular Function in Multiple Myeloma Patients

Background: Carfilzomib improves the prognosis of multiple myeloma (MM) patients but significantly increases cardiovascular toxicity. The timing and effect of Carfilzomib therapy on the left ventricular function is still under investigation. We sought to assess the echocardiographic systo-diastolic changes, including global longitudinal strain (GLS), in patients treated with Carfilzomib and to identify predictors of increased risk of cardiovascular adverse events (CVAEs) during therapy.

Methods: Eighty-eight patients with MM performed a baseline cardiovascular evaluation comprehensive of transthoracic echocardiogram (TTE) before the start of Carfilzomib therapy and after 6 months. All patients were clinically followed up to early identify the occurrence of CVAEs during the whole therapy duration.

Results: After Carfilzomib treatment, mean GLS slightly decreased (−22.2% ± 2.6 vs. −21.3% ± 2.5; p < 0.001). Fifty-eight percent of patients experienced CVAEs during therapy: 71% of them had uncontrolled hypertension, and 29% had major CVAEs or CV events not related to arterial hypertension. GLS variation during therapy was not related to an increased risk of CVAEs; however, patients with baseline GLS ≥ −21% and/or left ventricular ejection fraction (LVEF) ≤ 60% had a greater risk of major CVAEs (OR = 6.2, p = 0.004; OR = 3.7, p = 0.04, respectively). Carfilzomib led to a higher risk of diastolic dysfunction (5.6 vs. 13.4%, p = 0.04) and to a rise in E/e′ ratio (8.9 ± 2.7 vs. 9.7 ± 3.7; p = 0.006).

Conclusion: Carfilzomib leads to early LV function impairment early demonstrated by GLS changes and diastolic dysfunction. Baseline echocardiographic parameters, especially GLS and LVEF, might improve cardiovascular risk stratification before treatment.

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.

Altered proteasome function in right ventricular hypertrophy

AIMS

In patients with pulmonary hypertension, right ventricular hypertrophy (RVH) is a detrimental condition that ultimately results in right heart failure and death. The ubiquitin proteasome system has been identified as a major protein degradation system to regulate cardiac remodelling in the left heart. Its role in right heart hypertrophy, however, is still ambiguous.

METHODS AND RESULTS

RVH was induced in mice by pulmonary artery banding (PAB). Both, expression and activity of the proteasome was found to be up-regulated in the hypertrophied right ventricle (RV) compared to healthy controls. Catalytic inhibition of the proteasome by the two proteasome inhibitors Bortezomib (BTZ) and ONX-0912 partially improved RVH both in preventive and therapeutic applications. Native gel analysis revealed that specifically the 26S proteasome complexes were activated in experimental RVH. Increased assembly of 26S proteasomes was accompanied by elevated expression of Rpn6, a rate-limiting subunit of 26S proteasome assembly, in hypertrophied cardiomyocytes of the right heart. Intriguingly, patients with RVH also showed increased expression of Rpn6 in hypertrophied cardiomyocytes of the RV as identified by immunohistochemical staining.

CONCLUSION

Our data demonstrate that alterations in expression and activity of proteasomal subunits play a critical role in the development of RVH. Moreover, this study provides an improved understanding on the selective activation of the 26S proteasome in RVH that might be driven by the rate-limiting subunit Rpn6. In RVH, Rpn6 therefore represents a more specific target to interfere with proteasome function than the commonly used catalytic proteasome inhibitors.

Non-Hematologic Toxicity of Bortezomib in Multiple Myeloma: The Neuromuscular and Cardiovascular Adverse Effects

Simple Summary

Multiple myeloma (MM) is a still uncurable tumor of mainly elderly patients originating from the terminally differentiated B cells. Introduction to the treatment of MM patients of a new class of drugs called proteasome inhibitors (bortezomib followed by carfilzomib and ixazomib) significantly improved disease control. Proteasome inhibitors interfere with the major mechanism of protein degradation in a cell leading to the severe imbalance in the protein turnover that is deadly to MM cells. Currently, these drugs are the mainstream of MM therapy but are also associated with an increased rate of the injuries to multiple organs and tissues. In this review, we summarize the current knowledge on the molecular mechanisms of the first-in-class proteasome inhibitor bortezomib-induced disturbances in the function of peripheral nerves and cardiac and skeletal muscle.

Abstract

The overall approach to the treatment of multiple myeloma (MM) has undergone several changes during the past decade. and proteasome inhibitors (PIs) including bortezomib, carfilzomib, and ixazomib have considerably improved the outcomes in affected patients. The first-in-class selective PI bortezomib has been initially approved for the refractory forms of the disease but has now become, in combination with other drugs, the backbone of the frontline therapy for newly diagnosed MM patients, as well as in the maintenance therapy and relapsed/refractory setting. Despite being among the most widely used and highly effective agents for MM, bortezomib can induce adverse events that potentially lead to early discontinuation of the therapy with negative effects on the quality of life and outcome of the patients. Although peripheral neuropathy and myelosuppression have been recognized as the most relevant bortezomib-related adverse effects, cardiac and skeletal muscle toxicities are relatively common in MM treated patients, but they have received much less attention. Here we review the neuromuscular and cardiovascular side effects of bortezomib. focusing on the molecular mechanisms underlying its toxicity. We also discuss our preliminary data on the effects of bortezomib on skeletal muscle tissue in mice receiving the drug.

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.

Role of the Ubiquitin Proteasome System in the Regulation of Blood Pressure: A Review

The kidney and the vasculature play crucial roles in regulating blood pressure. The ubiquitin proteasome system (UPS), a multienzyme process mediating covalent conjugation of the 76-amino acid polypeptide ubiquitin to a substrate protein followed by proteasomal degradation, is involved in multiple cellular processes by regulating protein turnover in various tissues. Increasing evidence demonstrates the roles of UPS in blood pressure regulation. In the kidney, filtered sodium is reabsorbed through diverse sodium transporters and channels along renal tubules, and studies conducted till date have provided insights into the complex molecular network through which ubiquitin ligases modulate sodium transport in different segments. Components of these pathways include ubiquitin ligase neuronal precursor cell-expressed developmentally downregulated 4-2, Cullin-3, and Kelch-like 3. Moreover, accumulating data indicate the roles of UPS in blood vessels, where it modulates nitric oxide bioavailability and vasoconstriction. Cullin-3 not only regulates renal salt reabsorption but also controls vascular tone using different adaptor proteins that target distinct substrates in vascular smooth muscle cells. In endothelial cells, UPS can also contribute to blood pressure regulation by modulating endothelial nitric oxide synthase. In this review, we summarize current knowledge regarding the role of UPS in blood pressure regulation, focusing on renal sodium reabsorption and vascular function.

Liposomes Loaded with the Proteasome Inhibitor Z-Leucinyl-Leucinyl-Norleucinal are Effective in Inducing Apoptosis in Colorectal Cancer Cell Lines

Colorectal cancer (CRC) is one of the main causes of cancer-related death in developed countries. Targeted therapies and conventional chemotherapeutics have been developed to help treat this type of aggressive cancer. Among these, the monoclonal antibodies cetuximab (Cxm) and panitumumab specifically target and inactivate the signaling of ERBB1 (EGF receptor), a key player in the development and progression of this cancer. Unfortunately, these antibodies are effective only on a small fraction of patients due to primary or secondary/acquired resistance. However, as ERBB1 cell surface expression is often maintained in resistant tumors, ERBB1 can be exploited as a target to deliver other drugs. Liposomes and immunoliposomes are under intensive investigation as pharmaceutical nanocarriers and can be functionalized with specific antibodies. In this study, we first investigated the anti-cancer activity of a cell permeable tripeptide, leucine-leucin-norleucinal (LLNle), an inhibitor of gamma-secretase and proteasome, in three different CRC cell lines that express ERBB1. We formulated LLNle-liposomes and Cxm-conjugated LLNle-loaded liposomes (LLNle-immunoliposomes) and evaluated their efficacy in inhibiting cell survival. Despite similar pro-apoptotic effects of free LLNle and LLNle-liposomes, immunoliposomes-LLNle were significantly less effective than their unconjugated counterparts. Indeed, immunoliposomes-LLNle were readily internalized and trafficked to lysosomes, where LLNle was likely trapped and/or inactivated. In conclusion, we demonstrated that LLNle was readily delivered to CRC cell lines by liposomes, but immunoliposomes-LLNle failed to show significant anti-cancer activity.

MicroRNAs in Cancer Treatment-Induced Cardiotoxicity

Cancer treatment has made significant progress in the cure of different types of tumors. Nevertheless, its clinical use is limited by unwanted cardiotoxicity. Aside from the conventional chemotherapy approaches, even the most newly developed, i.e., molecularly targeted therapy and immunotherapy, exhibit a similar frequency and severity of toxicities that range from subclinical ventricular dysfunction to severe cardiomyopathy and, ultimately, congestive heart failure. Specific mechanisms leading to cardiotoxicity still remain to be elucidated. For instance, oxidative stress and DNA damage are considered key players in mediating cardiotoxicity in different treatments. microRNAs (miRNAs) act as key regulators in cell proliferation, cell death, apoptosis, and cell differentiation. Their dysregulation has been associated with adverse cardiac remodeling and toxicity. This review provides an overview of the cardiotoxicity induced by different oncologic treatments and potential miRNAs involved in this effect that could be used as possible therapeutic targets.

The effects of rosiglitazone on the neonatal rat cardiomyocyte transcriptome: a temporal analysis

Aim: The objective was to determine via high-throughput RNA sequencing the temporal effects of rosiglitazone (Avandia®) on the neonatal rat ventricular myocyte transcriptome. Materials & methods: Neonatal rat ventricular myocytes (NRVMs) were exposed to rosiglitazone in vitro. Meta analyses utilized temporal comparisons of 0.5 h control versus 0.5 h treatment, 0.5 h treatment versus 24 h treatment and 24 h treatment versus 48 h treatment. Results: Time dependent responses were observed. At 0.5 h, the PI3K-AKT signaling pathway was impacted. At 24 h endoplasmic reticulum activity and protein degradation were altered. At 48 h, oxytocin signaling was perturbed. Conclusion: The effects of rosiglitazone occured early and increased in magnitude over time. A protective molecular response was triggered at 24 h and maintained until 48 h. In parallel, a response that can cause cardiac damage was activated. Our findings suggest that rosiglitazone has deleterious effects.

Ubiquitin-based modifications in endothelial cell-cell contact and inflammation

Endothelial cell-cell contacts are essential for vascular integrity and physiology, protecting tissues and organs from edema and uncontrolled invasion of inflammatory cells. The vascular endothelial barrier is dynamic, but its integrity is preserved through a tight control at different levels. Inflammatory cytokines and G-protein-coupled receptor agonists, such as histamine, reduce endothelial integrity and increase vascular leakage. This is due to elevated myosin-based contractility, in conjunction with phosphorylation of proteins at cell-cell contacts. Conversely, reducing contractility stabilizes or even increases endothelial junctional integrity. Rho GTPases are key regulators of such cytoskeletal dynamics and endothelial cell-cell contacts. In addition to signaling-induced regulation, the expression of junctional proteins, such as occludin, claudins and vascular endothelial cadherin, also controls endothelial barrier function. There is increasing evidence that, in addition to protein phosphorylation, ubiquitylation (also known as ubiquitination) is an important and dynamic post-translational modification that regulates Rho GTPases, junctional proteins and, consequently, endothelial barrier function. In this Review, we discuss the emerging role of ubiquitylation and deubiquitylation events in endothelial integrity and inflammation. The picture that emerges is one of increasing complexity, which is both fascinating and promising given the clinical relevance of vascular integrity in the control of inflammation, and of tissue and organ damage.

In vitro and in vivo investigation of cardiotoxicity associated with anticancer proteasome inhibitors and their combination with anthracycline

Although proteasome inhibitors (PIs) are modern targeted anticancer drugs, they have been associated with a certain risk of cardiotoxicity and heart failure (HF). Recently, PIs have been combined with anthracyclines (ANTs) to further boost their anticancer efficacy. However, this raised concerns regarding cardiac safety, which were further supported by several in vitro studies on immature cardiomyocytes. In the present study, we investigated the toxicity of clinically used PIs alone (bortezomib (BTZ), carfilzomib (CFZ)) as well as their combinations with an ANT (daunorubicin (DAU)) in both neonatal and adult ventricular cardiomyocytes (NVCMs and AVCMs) and in a chronic rabbit model of DAU-induced HF. Using NVCMs, we found significant cytotoxicity of both PIs around their maximum plasma concentration (c_max) as well as significant augmentation of DAU cytotoxicity. In AVCMs, BTZ did not induce significant cytotoxicity in therapeutic concentrations, whereas the toxicity of CFZ was significant and more profound. Importantly, neither PI significantly augmented the cardiotoxicity of DAU despite even more profound proteasome-inhibitory activity in AVCMs compared with NVCMs. Furthermore, in young adult rabbits, no significant augmentation of chronic ANT cardiotoxicity was noted with respect to any functional, morphological, biochemical or molecular parameter under study, despite significant inhibition of myocardial proteasome activity. Our experimental data show that combination of PIs with ANTs is not accompanied by an exaggerated risk of cardiotoxicity and HF in young adult animal cardiomyocytes and hearts.

Myocyte-Damaging Effects and Binding Kinetics of Boronic Acid and Epoxyketone Proteasomal-Targeted Drugs

The proteasome inhibitors bortezomib, carfilzomib, and ixazomib, which are used in the treatment of multiple myeloma have greatly improved response rates. Several other proteasome inhibitors, including delanzomib and oprozomib, are in clinical trials. Carfilzomib and oprozomib are epoxyketones that form an irreversible bond with the 20S proteasome, whereas bortezomib, ixazomib, and delanzomib are boronic acids that form slowly reversible adducts. Several of the proteasome inhibitors have been shown to exhibit specific cardiac toxicities. A primary neonatal rat myocyte model was used to study the relative myocyte-damaging effects of five proteasome inhibitors with a view to identifying potential class differences and the effect of inhibitor binding kinetics. Bortezomib was shown to induce the most myocyte damage followed by delanzomib, ixazomib, oprozomib, and carfilzomib. The sensitivity of myocytes to proteasome inhibitors, which contain high levels of chymotrypsin-like proteasomal activity, may be due to inhibition of proteasomal-dependent ongoing sarcomeric protein turnover. All inhibitors inhibited the chymotrypsin-like proteasomal activity of myocyte lysate in the low nanomolar concentration range and exhibited time-dependent inhibition kinetics characteristic of slow-binding inhibitors. Progress curve analysis of the inhibitor concentration dependence of the slow-binding kinetics was used to measure second-order "on" rate constants for binding. The second-order rate constants varied by 90-fold, with ixazomib reacting the fastest, and oprozomib the slowest. As a group, the boronic acid drugs were more damaging to myocytes than the epoxyketone drugs. Overall, inhibitor-induced myocyte damage was positively, but not significantly, correlated with their second-order rate constants.

Arterial hypertension in cancer: The elephant in the room

The great therapeutical success achieved by oncology is counterbalanced by growing evidences of cardiovascular (CV) toxicity due to many antineoplastic treatments. Cardiac adverse events may cause premature discontinuation of effective oncologic treatments or occur as late events undermining the oncologic success. Arterial hypertension is both the most common comorbidity in cancer patients and a frequent adverse effect of anticancer therapies. A pre-existing hypertension is known to increase the risk of other cardiac adverse events due to oncologic treatments, in particular heart failure. Moreover, as a strict association between cancer and CV diseases has emerged over the recent years, various analyses have shown a direct relationship between hypertension and cancer incidence and mortality. Finally, many antineoplastic treatments may cause a rise in blood pressure (BP) values, particularly the novel anti VEGF agents, this possibly compromising efficacy of chemotherapy. Aim of this review is to revise the topic and the many aspects linking arterial hypertension and cancer, and to provide a comprehensive and practical guide of the current treatment approaches.

Cardiovascular adverse events in multiple myeloma patients

Multiple myeloma is a malignant disease, caused by an uncontrolled clonal proliferation of a specific group of white blood cells, the plasma cells. Clinical manifestations include bone pain due to osteolysis, hypercalcemia, anemia, and renal insufficiency. Proteasome inhibitors have substantially improved survival of patients suffering from multiple myeloma, providing an efficient treatment option mainly for relapsed and refractory multiple myeloma. Although constituting one substance class, bortezomib, carfilzomib, and ixazomib differ greatly regarding their non-hematologic side effects. This article reviews the clinical and preclinical data on approved proteasome inhibitors in an attempt to decipher the underlying pathomechanisms related to cardiovascular adverse events seen in clinical trials.

Cardiovascular safety of oncologic agents: a double-edged sword even in the era of targeted therapies - Part 2

INTRODUCTION

Patients with cancer are subject to the cardiotoxic effects of cancer therapy. Improved cancer treatments lead to more cancer-survivors, who though are exposed to various forms of cardiovascular (CV) disease (CVD) as they age. Aging patients are at increased risk of developing both malignancy and CVD or they may have survived some form of CVD as a result of effective CV treatments. Furthermore, patients with CVD may develop cancer and require treatment (and vice versa), all contributing to increased morbidity and mortality. The prevalence of both malignancy and CVD will increase due to the trend toward a longer lifespan.

AREAS COVERED

In part 2 of this review, the discussion of the CV effects of specific oncology drugs is completed with inclusion of additional immunological agents, current hormonal and other agents. Early detection and monitoring of cardiotoxicity, use of biomarkers and other imaging and diagnostic methods and prevention and treatment options are also discussed.

EXPERT OPINION

As outlined in part 1 of this review, oncologists need to be aware of the CV adverse-effects of their treatments and make careful and expectant clinical decisions, especially in patients with preexisting CVD or CV risk factors. Similarly, cardiologists should consider a detailed previous history of treatment for malignant disease, including prior chemotherapy exposure, dose(s) received, and/or combined modality therapy with chest radiotherapy. Both specialists should collaborate in order to minimize the impact of these two ubiquitous diseases (cancer and CVD) and mitigate the adverse effects of treatment modalities.

Cardiovascular safety of oncologic agents: A double-edged sword even in the era of targeted therapies - part 1

INTRODUCTION

Patients with cancer are subject to the cardiotoxic effects of cancer therapy and as more patients survive cancer due to improved treatment they are exposed to various forms of cardiovascular (CV) disease as they age, and vice-versa. Such an interplay of age with both malignancy and CV disease may contribute to increased morbidity and mortality.

AREAS COVERED

This two-part review considers the effects of cancer drug treatment on the CV system. In Part I, the various types of CV and cardiometabolic toxicity of anti-cancer drugs and the possible mechanisms involved are discussed. Also, among the specific oncologic agents, the CV effects of the classical agents and of the large molecule immunological agents (monoclonal antibodies, including immune checkpoint inhibitors) are detailed.

EXPERT OPINION

Oncologic agents produce a variety of CV adverse effects, including cardiomyopathy and heart failure, peri-myocarditis, coronary artery disease, peripheral vascular disease, hypertension (HTN), cardiac arrhythmias, valvular heart disease, and pulmonary HTN. Both the oncologist and the cardiologist need to be aware of such adverse effects and of the specific agents that produce them. They need to join forces to prevent, anticipate, recognize, and manage such complications.