The clinical use of anthracyclines like doxorubicin and daunorubicin can be viewed as a sort of double-edged sword. On the one hand, anthracyclines play an undisputed key role in the treatment of many neoplastic diseases; on the other hand, chronic administration of anthracyclines induces cardiomyopathy and congestive heart failure usually refractory to common medications. Second-generation analogs like epirubicin or idarubicin exhibit improvements in their therapeutic index, but the risk of inducing cardiomyopathy is not abated. It is because of their janus behavior (activity in tumors vis-a-vis toxicity in cardiomyocytes) that anthracyclines continue to attract the interest of preclinical and clinical investigations despite their longer-than-40-year record of longevity. Here we review recent progresses that may serve as a framework for reappraising the activity and toxicity of anthracyclines on basic and clinical pharmacology grounds. We review 1) new aspects of anthracycline-induced DNA damage in cancer cells; 2) the role of iron and free radicals as causative factors of apoptosis or other forms of cardiac damage; 3) molecular mechanisms of cardiotoxic synergism between anthracyclines and other anticancer agents; 4) the pharmacologic rationale and clinical recommendations for using cardioprotectants while not interfering with tumor response; 5) the development of tumor-targeted anthracycline formulations; and 6) the designing of third-generation analogs and their assessment in preclinical or clinical settings. An overview of these issues confirms that anthracyclines remain "evergreen" drugs with broad clinical indications but have still an improvable therapeutic index.

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Anthracyclines: Molecular Advances and Pharmacologic Developments in Antitumor Activity and Cardiotoxicity

Roles of the raf/mek/erk pathway in cell growth, malignant transformation and drug resistance

Doxorubicin (Adriamycin) has been used in oncologic practice since the late 1960s. It held promise as a powerful drug in the fight against cancer. The tumors most commonly responding to doxorubicin when it is given as a single agent or in combination with other antitumor agents include breast and esophageal carcinomas; osteosarcoma, Kaposi's sarcoma, and soft-tissue sarcomas; and Hodgkin's and non-Hodgkin's lymphomas. Other cancers that are less responsive to doxorubicin but that are still treated with the drug because of its overall benefits include gastric, liver, bile-duct, pancreatic, and endometrial carcinomas. However, reports of fatal cardiotoxic effects of doxorubicin have . . .

Doxorubicin-Induced Cardiomyopathy

Reduced cardiotoxicity and comparable efficacy in a phase III trial of pegylated liposomal doxorubicin HCl (CAELYX™/Doxil®) versus conventional doxorubicin for first-line treatment of metastatic breast cancer

Doxorubicin is believed to cause dose-dependent cardiotoxicity through redox cycling and the generation of reactive oxygen species (ROS). Here we show that cardiomyocyte-specific deletion of Top2b (encoding topoisomerase-IIβ) protects cardiomyocytes from doxorubicin-induced DNA double-strand breaks and transcriptome changes that are responsible for defective mitochondrial biogenesis and ROS formation. Furthermore, cardiomyocyte-specific deletion of Top2b protects mice from the development of doxorubicin-induced progressive heart failure, suggesting that doxorubicin-induced cardiotoxicity is mediated by topoisomerase-IIβ in cardiomyocytes.

Identification of the molecular basis of doxorubicin-induced cardiotoxicity

Adriamycin (doxorubicin) is one of the most effective chemotherapeutic agents against a variety of cancers, but its usefulness is seriously curtailed by the risk of developing heart failure. Available laboratory evidence suggests that an increase in oxidative stress, brought about by increased free radical production and decreased myocardial endogenous antioxidants, plays an important role in the pathogenesis of heart failure. Adriamycin-induced apoptosis and hyperlipidemia may also be involved in the process. Probucol, a lipid-lowering drug and an antioxidant, completely prevents the occurrence of heart failure by reducing oxidative stress as well as by the modulation of apoptis and high lipid concentrations. Thus, combined therapy with adriamycin and probucol has a high potential for optimizing the treatment of cancer patients.

Adriamycin-induced heart failure: mechanism and modulation.

Current knowledge about adriamycin cardiomyopathy indicates that the major cause of this condition is increased oxidative stress although the drug's antitumor action in patients may involve other mechanisms. Controversies about the different antioxidants in preventing cardiomyopathy likely stem from the fact that antioxidants must be effective in both the lipid and water phases, and the dose must be optimal, in order to be protective. Probucol, an antioxidant and promoter of endogenous antioxidants, is one such agent. Conducting clinical trials with an optimal dose of probucol is the next step and should make this great anticancer drug safer and more efficient in the fight against the cancer.

https://faseb.onlinelibrary.wiley.com/doi/pdf/10.1096/fasebj.11.12.9337145

Adriamycin cardiomyopathy: pathophysiology and prevention.

Adriamycin-induced cardiomyopathic changes are prevented by combination therapy with probucol. These beneficial effects are suggested to be due to a combination of antioxidant as well as lipid-lowering effects of probucol. In the present study, we compared the effects of probucol (PROB) with that of lovastatin (LOV), a lipid-lowering drug, and trolox (TRO), an antioxidant, on adriamycin (ADR)-induced subchronic in vivo changes in serum free fatty acids (FFA), serum albumin and myocardial reduced (GSH) and oxidized (GSSG) glutathione in rats. ADR caused a significant increase in FFA, decrease in albumin, and an increase in FFA/albumin. PROB and LOV modulated the increases in FFA and FFA/albumin, while TRO was without any effect. ADR reduced myocardial GSH, increased GSSG and decreased GSH/GSSG. Only PROB caused significant improvement in GSH and normalized GSSG levels. It is suggested that these modulatory effects of probucol may also contribute in the beneficial effects of this drug against adriamycin-induced cardiomyopathy and congestive heart failure. (Mol Cell Biochem 188: 161–166, 1998)

Modulation of adriamycin-induced changes in serum free fatty acids, albumin and cardiac oxidative stress

Adriamycin, an effective anticancer chemotherapeutic agent, causes an insidious and delayed cardiotoxicity. Different subcellular abnormalities including calcium transport changes in the sarcolemma (SL) as well as downregulation of the adrenergic system have been shown to be associated with the development of this cardiomyopathy. Since both of these activities are influenced by phospholipid methylation, effects of adriamycin on the three catalytic sites of SL phosphatidylethanolamine N-methyltransferase were examined. Rats were administered with a cumulative dose of adriamycin (15 mg/kg) over 2 weeks and examined after 3 weeks. Vehicle injected animals served as controls. Dyspnea, high mortality rate, ascites and decrease in aortic and left ventricular systolic pressure, as well as increase in left ventricular end diastolic pressure were seen in the adriamycin group. Myocardial cell damage typical of adriamycin cardiomyopathy, i.e. sarcotubular swelling, vacuolization and myofibrillar drop-out, was also apparent. Total methyl group incorporation into SL phosphatidylethanolamine using radiolabeled S-adenosyl-L-methionine as the donor was significantly depressed in the 3 week group at catalytic sites II and III. Decreased production of methylated intermediates, phosphatidyl-N-monomethylethanolamine and phosphatidyl-N,N-dimethylethanolamine as well as phosphatidylcholine (PC) was seen. Depression of phosphatidylethanolamine N-methylation was also noticed when SL, isolated from untreated hearts, was exposed in vitro to different concentrations (10, 100 and 1000 (μM) of adriamycin. Inhibition of phosphatidylethanolamine N-methylation appears to be mediated by adriamycin-induced increase in the oxidative stress and may contribute in the pathogenesis of subcellular changes associated with this cardiomyopathy. (Mol Cell Biochem 176: 235–240, 1997)

Natasha Iliskovic

Papers

Doxorubicin-Induced Cardiomyopathy

Adriamycin-induced heart failure: mechanism and modulation.

Adriamycin cardiomyopathy: pathophysiology and prevention.

Modulation of adriamycin-induced changes in serum free fatty acids, albumin and cardiac oxidative stress

Adriamycin depresses in vivo and in vitro phosphatidylethanolamine N-methylation in rat heart sarcolemma.