Randomized Trial of Lisinopril Versus Carvedilol to Prevent Trastuzumab Cardiotoxicity in Patients With Breast Cancer

BackgroundTrastuzumab is highly effective for human epidermal growth factor receptor type 2 (HER2)–positive breast cancer but is associated with a decline in left ventricular ejection fraction.ObjectivesThe purpose of this study was to determine whether angiotensin-converting enzyme inhibitors or beta-blockers reduce the rate of trastuzumab-induced cardiotoxicity (left ventricular ejection fraction decrease >10%, or >5% if below 50%) and limit treatment interruptions.MethodsIn this double-blind, multicenter, placebo-controlled trial, cardiotoxicity and treatment interruptions in patients with HER2-positive breast cancer treated with trastuzumab for 12 months were evaluated over a 2-year period. Patients were stratified by anthracycline use and then randomized to receive lisinopril, carvedilol, or placebo.ResultsThe study included 468 women, age 51 ± 10.7 years. For the entire cohort, cardiotoxicity was comparable in the 3 arms and occurred in 32% of patients on placebo, 29% on carvedilol, and 30% on lisinopril. For patients receiving anthracyclines, the event rates were higher in the placebo group (47%) than in the lisinopril (37%) and the carvedilol (31%) groups. Cardiotoxicity-free survival was longer on both carvedilol (hazard ratio: 0.49; 95% confidence interval: 0.27 to 0.89; p = 0.009) and lisinopril (hazard ratio: 0.53; 95% confidence interval: 0.30 to 0.94; p = 0.015) than on placebo. In the whole cohort, as well as in the anthracycline arm, patients on active therapy with either angiotensin-converting enzyme inhibitor or beta-blockers experienced fewer interruptions in trastuzumab than those on placebo.ConclusionsIn patients with HER2-positive breast cancer treated with trastuzumab, both lisinopril and carvedilol prevented cardiotoxicity in patients receiving anthracyclines. For such patients, lisinopril or carvedilol should be considered to minimize interruptions of trastuzumab. (Lisinopril or Coreg CR in Reducing Side Effects in Women With Breast Cancer Receiving Trastuzumab; NCT01009918)     

Emetine inhibits glycolysis in isolated, perfused rat hearts

This work was designed to test whether phosphofructokinase is a target for emetine action on the heart. The effects of 37, μM emetine on the activities of phosphofructokinase and hexokinase were measured in homogenates from perfused hearts. The action of increasing concentrations of emetine was determined in nonperfused heart homogenates. The effect of 37 μM emetine or control solutions on the concentration of fructose-6-phosphate and fructose-1,6-phosphate was measured. The effect of 37 μM emetine or control perfusion on the utilization of fructose-6-phosphate by phosphofructokinase in centrifugation supernatants of homogenates and in reconstituted 27,000g pellets was measured. Double-reciprocal plots of fructose-6-phosphate concentrations vs phosphofructokinase activities were plotted. Emetine decreased phosphofructokinase activity in homogenates from both perfused and nonperfused hearts. Emetine did not inhibit cardiac hexokinase activity. In homogenates from nonperfused hearts, the maximal inhibition with high concentrations of emetine was approx 50%. Emetine perfusion caused a simultaneous increase in the phosphofructokinase substrate fructose-6-phosphate and a decrease in the phosphofructokinase product fructose-1,6-bisphosphate. Phosphofructokinase and, consequently, glycolytic flux appear to be subcellular targets for emetine in the heart. Homogenate centrifugation studies indicate that emetine acts on bound rather than unbound phosphofructokinase. The inhibition may be uncompetitive in nature.     

BN52021 protects rat cardiomyocyte from doxorubicin induced cardiotoxicity

The aim of this study was to assess the role of platelet activating factor (PAF) antagonist BN52021 in doxorubicin induced cardiotoxicity and to explore the mechanisms. H9c2 cardiomyocytes were employed to investigate the effect of BN52021 on doxorubicin induced cell viability and cell apoptosis. Signaling pathway of caspase 3, cytochrome c, calcium and p38 mitogen-activated protein (MAPK) was determined during the doxorubicin induced apoptosis. Our results showed BN52021 pretreatment could protected cell death induced by doxorubicin in H9c2 cardiomyocytes. Decrease concentration of [Ca²⁺] and expression of phosphorylated P38 MAPK were accounted for the protection effect. Inhibition of signaling pathway of calcium and p38 MAPK showed similar effect exerted by BN52021 in doxorubicin induced cell apoptosis. Our results demonstrated BN52021 protected against doxorubicin induced cell death in H9c2 cardiomyocytes by calcium and p38 MAPK signaling in vitro. These finding may give insight on the treatment of doxorubicin induced cardiomyopathy.     

CDK4/6抑制剂帕博西尼的研究进展

细胞周期蛋白依赖性激酶(cyclin-dependent kinases, CDKs)在细胞周期的调控中起着至关重要的作用,是干扰肿瘤细胞分裂和增殖的特异治疗靶点。帕博西尼是全球首个CDK4/6特异性抑制剂,临床疗效显著,毒性可控,被批准联合来曲唑治疗绝经后ER+、HER2-的晚期乳腺癌患者,作为转移性疾病的初始内分泌治疗。目前已经开始研究这种抑制剂对其他恶性肿瘤的疗效。本文综述了帕博西尼的作用机制及其在不同肿瘤治疗中的研究进展,并对帕博西尼的发展前景进行了展望。     

MCP-1参与缬沙坦对阿霉素心脏毒性的预保护作用

目的　探讨阿霉素诱导SD大鼠心肌损伤模型中单核细胞趋化蛋白-1（MCP-1）蛋白表达及其潜在的干预机制。方法　选择8周龄雄性SPF级SD大鼠30只,按照随机数字表法分为3组：对照组（Con组,生理盐水灌胃＋腹腔注射）、阿霉素组（Dox组,1.25 mL/kg阿霉素腹腔注射+2 mL/kg生理盐水灌胃）及缬沙坦+阿霉素组（Val+Dox组,1.25 mL/kg阿霉素腹腔注射+2 mL/kg缬沙坦灌胃）各10只,连续干预6周。10周时超声心动图检测心功能变化,留取大鼠心肌组织,电镜观察心肌超微结构变化,采用蛋白芯片技术检测各组血清MCP-1、调节激活正常T细胞表达和分泌因子（RANTES）及次级淋巴组织趋化因子（6Ckine）蛋白含量,采用Western blot检测各组心肌组织MCP-1蛋白表达。结果　超声结果显示,与Con组相比,Dox组和Val+Dox组左心室射血分数（LVEF）、左心室短轴缩短率（LVFS）明显降低,左心室收缩末期内径（LVESD）、左心室舒张末期内径（LVEDD）明显升高（P＜0.05）。与Dox组相比,Val+Dox组LVEF、LVFS明显升高,LVESD、LVEDD明显降低（P＜0.05）。电镜下可见Con组心肌细胞结构清晰;Dox组心肌结构模糊,心肌溶解,可见自噬小体;Val+Dox组心肌结构模糊不清,线粒体体积增大、大小不等,但结构完整。与Con组相比,Dox组血清MCP-1、RANTES、6Ckine蛋白分别上调1.87倍、1.40倍和1.26倍（P＜0.05）。Western blot结果显示,Dox组与Con组相比,心肌组织MCP-1蛋白表达显著升高（P＜0.05）;Val+Dox组与Dox组相比,心肌组织MCP-1蛋白表达显著降低（P＜0.05）。结论　MCP-1蛋白可能参与阿霉素诱导的心肌损伤,缬沙坦可能通过下调MCP-1蛋白表达减轻心肌损伤。     

Human biology-based drug safety evaluation: scientific rationale,current status and future challenges

Introduction: Animal toxicity studies used to assess the safety of new candidate pharmaceuticals prior to their progression into human clinical trials are unable to assess the risk of non-pharmacologically mediated idiosyncratic adverse drug reactions (ADRs), the most frequent of which are drug-induced liver injury and cardiotoxicity. Idiosyncratic ADRs occur only infrequently and in certain susceptible humans, but are caused by many hundreds of different drugs and may lead to serious illness.

Areas covered: Idiosyncratic ADRs are initiated by drug-related chemical insults, which cause toxicity due to susceptibility factors that manifest only in certain patients. The chemical insults can be detected using in vitro assays. These enable useful discrimination between drugs that cause high versus low levels of idiosyncratic ADR concern. Especially promising assays, which have been described recently in peer-reviewed scientific literature, are highlighted.

Expert opinion: Effective interpretation of in vitro toxicity data requires integration of endpoints from multiple assays, which each address different mechanisms, and must also take account of human systemic and tissue drug exposure in vivo. Widespread acceptance and use of such assays has been hampered by the lack of correlation between idiosyncratic human ADR risk and toxicities observed in vivo in animals.     

Advances in nano-delivery systems for doxorubicin: an updated insight

Doxorubicin (DOX) is the most effective chemotherapeutic drug developed against broad range of cancers such as solid tumours, transplantable leukemias and lymphomas. Conventional DOX-induced cardiotoxicity has limited its use. FDA approved drugs i.e. non-pegylated liposomal (Myocet^®) and pegylated liposomal (Doxil^®) formulations have no doubt shown comparatively reduced cardiotoxicity, but has raised new toxicity issues. The entrapment of DOX in biocompatible, biodegradable and safe nano delivery systems can prevent its degradation in circulation minimising its toxicity with increased half-life, enhanced pharmacokinetic profile leading to improved patient compliance. In addition, nano delivery systems can actively and passively target the tumour resulting increase in therapeutic index and decreased side effects of drug. Foreseeing the need of a comprehensive review on DOX nanoformulations, in this article we for the first time have given an updated insight on DOX nano delivery systems.     

Hair Mercury and Fish Consumption in Residents of O‘ahu,Hawai‘i

Recent studies have established that men are susceptible to cardiotoxicity from methylmercury exposure, which also poses risks to the pregnant woman. Hair samples were obtained and questionnaires for methylmercury exposure assessment were administered to 110 adults (57 men, 53 women) throughout O‘ahu, Hawai‘i during December 2010 to January 2011. Hair samples were analyzed for total mercury with a direct mercury analyzer. Men ≥ 46 years had a median of 2.0 µg/g, which was above the reference dose of 1 µg/g, as compared to younger men with a median 1.0 µg/g (P < 0.05). Hair concentrations from older women had a median of 1.2 µg/g of mercury compared to 0.6 µg/g for younger women. Additionally, 38% of women of childbearing age had a Hazard Index > 1.0. This indicates that both men and women were at risk for excessive methylmercury exposure. In the final regression model, male gender, age > 45 years, length of residency > 10 years in Hawai‘i, and fish consumption frequency > 1 meal per week were significant factors in increased hair mercury levels. Following safe fish consumption practices allows residents to reap health benefits of fish consumption without excessive toxicant exposure.