Comparing the effects of various ß-blockers on cardiovascular mortality in breast cancer patients.

BACKGROUND: Cardiovascular (CV) disease is a leading cause of death in breast cancer (BC) patients due to the increased age and treatments. While individual ß-blockers have been investigated to manage CV complications, various ß-blockers have not been compared for their effects on CV death in this population. We aimed to compare CV mortality in older BC patients taking one of the commonly used ß-blockers. METHODS: This retrospective cohort study was conducted using the Surveillance, Epidemiology and End Results (SEER) - Medicare data (2010-2015). Patients of age 66 years or older at BC diagnosis receiving metoprolol, atenolol, or carvedilol monotherapy were included. The competing risk regression model was used to determine the risk of CV mortality in the three ß-blocker groups. The multivariable model was adjusted for demographic and clinical covariates. The adjusted hazard ratio (HR) and 95% confidence intervals (CI) were reported for the risk of CV mortality. RESULTS: The study cohort included 6,540 patients of which 55% were metoprolol users, 30% were atenolol users, and 15% were carvedilol users. Metoprolol was associated with a 37% reduced risk of CV mortality (P = 0.03) compared to carvedilol after adjusting for the covariates (HR = 0.63; 95% CI 0.41-0.96). No significant difference in the risk of CV mortality between atenolol and carvedilol users was observed (HR = 0.74; 95% CI 0.44-1.22). CONCLUSIONS: Our findings suggest that metoprolol is associated with a reduced risk of CV mortality in BC patients. Future studies are needed to confirm these findings and understand the mechanism of action.

Screening of GPCR drugs for repurposing in breast cancer.

Drug repurposing can overcome both substantial costs and the lengthy process of new drug discovery and development in cancer treatment. Some Food and Drug Administration (FDA)-approved drugs have been found to have the potential to be repurposed as anti-cancer drugs. However, the progress is slow due to only a handful of strategies employed to identify drugs with repurposing potential. In this study, we evaluated GPCR-targeting drugs by high throughput screening (HTS) for their repurposing potential in triple-negative breast cancer (TNBC) and drug-resistant human epidermal growth factor receptor-2-positive (HER2+) breast cancer (BC), due to the dire need to discover novel targets and drugs in these subtypes. We assessed the efficacy and potency of drugs/compounds targeting different GPCRs for the growth rate inhibition in the following models: two TNBC cell lines (MDA-MB-231 and MDA-MB-468) and two HER2+ BC cell lines (BT474 and SKBR3), sensitive or resistant to lapatinib + trastuzumab, an effective combination of HER2-targeting therapies. We identified six drugs/compounds as potential hits, of which 4 were FDA-approved drugs. We focused on ß-adrenergic receptor-targeting nebivolol as a candidate, primarily because of the potential role of these receptors in BC and its excellent long-term safety profile. The effects of nebivolol were validated in an independent assay in all the cell line models. The effects of nebivolol were independent of its activation of ß3 receptors and nitric oxide production. Nebivolol reduced invasion and migration potentials which also suggests its inhibitory role in metastasis. Analysis of the Surveillance, Epidemiology and End Results (SEER)-Medicare dataset found numerically but not statistically significant reduced risk of all-cause mortality in the nebivolol group. In-depth future analyses, including detailed in vivo studies and real-world data analysis with more patients, are needed to further investigate the potential of nebivolol as a repurposed therapy for BC.

Left Ventricular Noncompaction Is Associated with Valvular Regurgitation and a Variety of Arrhythmias.

Left ventricular noncompaction (LVNC) is a type of cardiomyopathy characterized anatomically by prominent ventricular trabeculation and deep intertrabecular recesses. The mortality associated with LVNC ranges from 5% to 47%. The etiology of LVNC is yet to be fully understood, although decades have passed since its recognition as a clinical entity globally. Furthermore, critical questions, i.e., whether LVNC represents an acquired pathology or has a congenital origin and whether the reduced contractile function in LVNC patients is a cause or consequence of noncompaction, remain to be addressed. In this study, to answer some of these questions, we analyzed the clinical features of LVNC patients. Out of 9582 subjects screened for abnormal cardiac functions, 45 exhibit the characteristics of LVNC, and 1 presents right ventricular noncompaction (RVNC). We found that 40 patients show valvular regurgitation, 39 manifest reduced systolic contractions, and 46 out of the 46 present different forms of arrhythmias that are not restricted to be caused by the noncompact myocardium. This retrospective examination of LVNC patients reveals some novel findings: LVNC is associated with regurgitation in most patients and arrhythmias in all patients. The thickness ratio of the trabecular layer to compact layer negatively correlates with fractional shortening, and reduced contractility might result from LVNC. This study adds evidence to support a congenital origin of LVNC that might benefit the diagnosis and subsequent characterization of LVNC patients.