Abemaciclib induces apoptosis in cardiomyocytes by activating the Hippo signaling pathway

Profiling the Cardiovascular Toxicities of CDK4/6 Inhibitors: A Real-World Pharmacovigilance Study

Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are approved for the treatment of human epidermal growth factor receptor 2 (HER-2)-negative, hormone receptor-positive breast cancer. The cardiovascular toxicity of CDK4/6 inhibitors is not well understood. This study aims to profile the cardiac events associated with CDK4/6 inhibitors. Reports from 2015Q1 to 2024Q1 were obtained from the FDA Adverse Event Reporting System (FAERS). Reports identifying palbociclib, ribociclib, and abemaciclib as the primary suspect were examined for cardiovascular toxicity, including hypertension, cardiac failure, cardiomyopathy, arrhythmia, myocardial infarction, and myocarditis. Signal detection was performed using the proportional reporting ratio (PRR), reporting odds ratio (ROR), and information component (IC). A total of 69,139 reports were analyzed. The median time to adverse events was 69 days (interquartile range [IQR], 18-260 days). Of these, 2065 reports documented cardiac adverse events. Ribociclib and QT prolongation were re-confirmed as a signal (PRR 8.43, ROR 8.65, IC025 2.86). Hypertension and cardiac failure were the most frequently reported cardiovascular toxicities. This study demonstrates that the use of CDK4/6 inhibitors is associated with cardiovascular adverse events, such as heart failure and hypertension. Further research is needed to understand the mechanisms and risk factors contributing to the cardiovascular toxicity of CDK4/6 inhibitors.

Abemaciclib-induced epithelial-mesenchymal transition mediated by cyclin-dependent kinase 4/6 independent of cell cycle arrest pathway

Abemaciclib (ABM), a cyclin-dependent kinase 4/6 inhibitor, shows pharmacological effects in cell cycle arrest. Epithelial-mesenchymal transition is an important cellular event associated with pathophysiological states such as organ fibrosis and cancer progression. In the present study, we evaluated the contribution of factors associated with cell cycle arrest to ABM-induced epithelial-mesenchymal transition. Treatment with 0.6 µM ABM induced both cell cycle arrest and epithelial-mesenchymal transition-related phenotypic changes. Interestingly, the knockdown of cyclin-dependent kinase 4/6, pharmacological targets of ABM or cyclin D1, which forms complexes with cyclin-dependent kinase 4/6, resulted in cell cycle arrest at the G1-phase and induction of epithelial-mesenchymal transition, indicating that downregulation of cyclin-dependent kinase 4/6-cyclin D1 complexes would mimic ABM. In contrast, knockdown of the Rb protein, which is phosphorylated by cyclin-dependent kinase 4/6, had no effect on the expression level of α-smooth muscle actin, an epithelial-mesenchymal transition marker. Furthermore, ABM-induced epithelial-mesenchymal transition was not affected by Rb knockdown, suggesting that Rb is not involved in the transition process. Our study is the first to suggest that cyclin-dependent kinase 4/6-cyclin D1 complexes, as pharmacological targets of ABM, may contribute to ABM-induced epithelial-mesenchymal transition, followed by clinical disorders such as organ fibrosis and cancer progression. This study suggests that blocking epithelial-mesenchymal transition might be a promising way to prevent negative side effects caused by a medication (ABM) without affecting its ability to treat the disease.

Cardiovascular complications of ribociclib in breast cancer patients

Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have unprecedentedly advanced hormone-dependent breast cancer treatment paradigm. In the metastatic setting, ribociclib has consistently demonstrated survival benefit in pre-, peri-, and postmenopausal patients, conjugating efficacy with health-related quality of life preservation. Accordingly, the emergence of cardiac and/or vascular adverse events related to this novel targeted agent is gaining significant interest. This narrative review provides an overview of the incidence and spectrum of cardiovascular toxicity, in both clinical trial framework and real-world evidence. The potential pathogenetic mechanism, along with the available diagnostic parameters including biomarkers, and proper management, are also summarized.

The cyclin-dependent kinase inhibitor abemaciclib-induced hepatotoxicity: Insight on the molecular mechanisms in HepG2/THP-1 co-culture model

Drug-induced liver injury (DILI) is one of the widespread causes of liver injury and immune system plays important role. Abemaciclib (ABE) is a cyclin-dependent kinase inhibitor used as monotherapy or combination therapy in the treatment of breast cancer. Like other kinase inhibitors, the underlying mechanisms of ABE-induced hepatotoxicity are not completely known yet. In the current study, hepatotoxicity of ABE was evaluated with HepG2/THP-1 co-culture model which has been developed in recent years for the evaluation of DILI potential. Following ABE treatment, oxidative stress, mitochondrial damage, cytokine secretion levels, apoptotic/necrotic cell death were determined. According to our results, ROS production along with GSH depletion was observed in HepG2 cells after ABE treatment. ABE promoted secretion of pro-inflammatory mediators (TNF-α and MCP-1) and declined anti-inflammatory cytokine IL-10 release. Besides, NFKβ and JNK1 protein expression levels increased following ABE treatment. ABE enhanced intracellular calcium levels, induced early apoptotic and necrotic cell deaths in HepG2 cells. Furthermore, the changes in some mitochondrial parameters including a reducement in intracellular ATP levels and complex V activity; hyperpolarized mitochondrial membrane potential and enhanced mitochondrial ROS levels were observed, whereas mitochondrial mass did not show any differences after ABE treatments. Therefore, ABE-induced hepatotoxic effects is probably via oxidative stress, inflammatory response and necrotic cell death rather than direct mitochondrial toxicity. In conclusion; the study makes a significant contribution to strengthening the infrastructure we have on in vitro toxicity mechanism evaluations, which are the basis of preclinical toxicity studies.

Dual regulation of Akt and glutathione caused by isoalantolactone effectively triggers human ovarian cancer cell apoptosis

<p indent="0mm">Ovarian cancer is one of leading causes of cancer death in gynecological tumor. Isoalantolactone (IL), present in several medicinal plants, exhibits various biological activities, and its mechanism underlying anti-ovarian cancer activity needs to be further investigated. Here, we find that IL inhibits the proliferation of SKOV-3 and OVCAR-3 cells by causing G2/M phase arrest and inducing apoptosis. Moreover, IL decreases intracellular glutathione (GSH) level, and induces reactive oxygen species (ROS) generation in SKOV-3 cells. Furthermore, IL induces inactivation of Akt which is required for the cytotoxicity of IL. In addition, overexpression of Akt attenuates the IL-induced growth inhibition and ROS generation. GSH supplementation moderately increases the expression of phospho-Akt. Further investigation reveals that pretreatment with L-buthionine-sulfoximine (a GSH biosynthesis inhibitor) restores the Akt-mediated attenuation of growth inhibition induced by IL. Moreover, co-treatment with IL and wortmannin (an Akt pathway inhibitor) increases the growth inhibition attenuated by pretreatment with N-acetyl-L-cysteine (a precursor for GSH biosynthesis). These results indicate that inactivation of Akt and downregulation of GSH level induced by IL are related to each other. In conclusion, combined targeting Akt and GSH is an effective strategy for cancer therapy and IL can be a promising anticancer agent for further exploration.</p>.

The protective effect of curcumin on cardiac markers and fibrosis in abemaciclib-induced cardiac damage in rats

Abemaciclib (ABE) is a cyclin-dependent kinase inhibitor used in combination with an antiestrogen in the treatment of breast cancer. In addition to the important therapeutic properties of this drug, its side effects are not fully known. In this study, we aimed to investigate the protective effect of curcumin (CUR) on cardiac damage caused by ABE administration. Forty rats were equally divided into control, dimethyl sulfoxide (150 µL), CUR (30 mg/kg/day), ABE (26 mg/kg/day), and ABE + CUR (26 mg/kg/day ABE and 30mg/kg/day CUR) groups (n = 8). Injections were administered daily for 28 days. Troponin-I, total cholesterol, and creatine kinase myocardial band (CK-MB) levels and cardiac fibrosis were higher in the ABE group than in the control group (p < 0.05), and were lower in the ABE + CUR group than in the ABE group (p < 0.05). The results showed that ABE administration can cause cardiac damage and increase cardiac fibrosis. However, they showed that coadministration of CUR with ABE could suppress increases in CK-MB, troponin-I, and total cholesterol levels and also cardiac fibrosis associated with cardiac damage. Therefore, we can infer that the subsequent administration of CUR ABE treatment can be used as a therapeutic strategy for preventing cardiac damage.

Elevated transaminases and development of cardiomyopathy in a 32-year-old woman with metastatic breast cancer after treatment with ribociclib followed by palbociclib

INTRODUCTION

Cyclin-dependent kinase 4 and 6 inhibitors, ribociclib and palbociclib, are associated with reports of transaminitis and adverse cardiac events.

CASE REPORT

The patient is a previously healthy 32-year-old female diagnosed with estrogen receptor-positive, progesterone receptor-positive, and human epidermal growth factor 2 negative metastatic breast cancer. From July to September 2021, the patient was initiated on ribociclib followed by palbociclib for metastatic breast cancer. She subsequently experienced two episodes of transaminitis and was diagnosed with cardiomyopathy.

MANAGEMENT AND OUTCOME

The patient experienced transaminitis 2 weeks after the initiation of ribociclib resulting in discontinuation. When rechallenged with palbociclib, the patient experienced transaminitis within 1 week of initiation, which resulted in discontinuation. Approximately 1 month after palbociclib discontinuation, the patient was diagnosed with congestive heart failure with a left ventricular ejection fraction of 24%.

DISCUSSION

To our knowledge, there are few case studies investigating cyclin-dependent kinase 4 and 6 inhibitor rechallenge following transaminitis. Prior literature suggests that transaminitis with cyclin-dependent kinase 4 and 6 inhibitors is not a class effect, but this case report suggests otherwise. This report presents a rare case of cardiomyopathy and transaminitis following the administration of cyclin-dependent kinase 4 and 6 inhibitors, ribociclib and palbociclib.

Myocardial dysfunction caused by abemaciclib: a case report

A 68-year-old female patient with metastatic breast cancer presented 12 weeks after starting chemotherapy with abemaciclib and fulvestrant with breathlessness, peripheral edema, and weight gain. Brain natriuretic peptide (BNP) and troponin I levels were raised above normal, and chest radiography revealed an increase in the cardiothoracic ratio from 47% before chemotherapy to 55%. The transthoracic echocardiogram showed a reduction in left ventricular ejection fraction from 76% before chemotherapy to 68%. Contrast-enhanced cardiac magnetic resonance imaging (MRI) revealed delayed accumulation in the interventricular septum. Under the diagnosis of abemaciclib-induced myocardial dysfunction and heart failure, abemaciclib was discontinued, and enalapril and furosemide were started. Two months later, imaging revealed a cardiothoracic ratio of 47% with a left ventricular ejection fraction of 73%. A cardiac MRI after three months was normal. This case report demonstrates that cardiac dysfunction caused by abemaciclib is reversible if detected early and treated appropriately.