Epirubicin - CAS 56420-45-2 Catalog number: BADC-00801

In Vitro

The cytotoxicity of epirubicin, LAK, and LAK + epirubicin (1/10 of IC50) was evaluated in 400-fold epirubicin resistant MCF-7 EPI(R) (P-glycoprotein overexpressing) and drug-sensitive MCF-7 WT cells. IC50 values were measured using the MTT cytotoxicity test. The MCF-7 EPI(R) cells exhibited an increased susceptibility to LAK cells than did the MCF-7 WT cells. P-gp+ MCF-7 EPI(R) cells were lysed by human LAK cells to a greater extend than were their drug-sensitive counterparts. LAK + epirubicin combined treatment increased susceptibility of MCF-7 WT and MCF-7 EPI(R) cells to LAK cells cytotoxicity. For both cell lines, cytotoxicity was dependent upon the concentration of the epirubicin and effector cell/target cell (E/T) ratio. The resistance of MCF-7 EPI(R) cells to epirubicin appears to be associated with a developed tolerance to superoxide, most likely because of a tree-fold increase in superoxide dismutase (SOD) activity and 13-fold augmented selenium dependent glutathione peroxidase (GSH-Px) activity.

In Vivo

Epirubicin is an antineoplastic agent of anthracycline antibiotic, used for treating a variety of tumor types such as lymphoma, cancer of the breast, lung, ovary and stomach. In vitro and in vivo studies revealed the significantly uptake of 99mTc-epirubicin in the tumor, and also indicating the efficiency of 99mTc-epirubicin as a tumor diagnostic agent.

Mechanism Of Action

Epirubicin has antimitotic and cytotoxic activity. It inhibits nucleic acid (DNA and RNA) and protein synthesis through a number of proposed mechanisms of action: Epirubicin forms complexes with DNA by intercalation between base pairs, and it inhibits topoisomerase II activity by stabilizing the DNA-topoisomerase II complex, preventing the religation portion of the ligation-religation reaction that topoisomerase II catalyzes. It also interferes with DNA replication and transcription by inhibiting DNA helicase activity.

Pharmacology

Epirubicin is an antineoplastic in the anthracycline class. General properties of drugs in this class include: interaction with DNA in a variety of different ways including intercalation (squeezing between the base pairs), DNA strand breakage and inhibition with the enzyme topoisomerase II. Most of these compounds have been isolated from natural sources and antibiotics. However, they lack the specificity of the antimicrobial antibiotics and thus produce significant toxicity. The anthracyclines are among the most important antitumor drugs available. Doxorubicin is widely used for the treatment of several solid tumors while daunorubicin and idarubicin are used exclusively for the treatment of leukemia. Epirubicin may also inhibit polymerase activity, affect regulation of gene expression, and produce free radical damage to DNA. Epirubicin possesses an antitumor effect against a wide spectrum of tumors, either grafted or spontaneous. The anthracyclines are cell cycle-nonspecific.

Toxicity (LD50)

Instances of administration of doses higher than recommended have been reported at doses ranging from 150 to 250 mg/sq m. The observed adverse events in these patients were qualitatively similar to known toxicities of epirubicin. Most of the patients recovered with appropriate supportive care. Secondary acute myelogenous leukemia (AML) has been reported in patients with breast cancer treated with anthracyclines, including epirubicin. Cardiac toxicity, including fatal congestive heart failure (CHF), may occur either during therapy with epirubicin or months to years after termination of therapy. Epirubicin was clastogenic in vitro (chromosome aberrations in human lymphocytes) both in the presence and absence of metabolic activation.