Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.3.44 (P-glycoprotein)
 13,344 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this work three human cell lines with multidrug resistance (MDR) caused by a P-glycoprotein (PGP) overexpression, CEM VLB, HL60 DNR, LOVO DX and two cell lines with MDR associated with a multidrug related protein (MRP) or a lung resistance-related protein (LRP) overexpression named GLC4 ADR and SW1573/2R120 were tested for Amifostine protection against Daunorubicin, Doxorubicin, Idarubicin and Mitoxantrone toxicity. This class of anticancer agents was chosen because they are commonly used in the first line treatments of acute leukemias where a PGP, an LRP or an MRP overexpression often occurs even at onset. A 7-day incubation with escalating doses of anticancer agents with or without a 15 minute preincubation in Amifostine or its active metabolite WR-1065 were used. In conclusion, in none of the MDR positive and negative cell lines did Amifostine modify the toxicity of the anticancer drugs. The observation that even the WR-1065 metabolite gave no protection against Anthracyclines toxicity strengthened the data and provided confirmation for the further in vivo testing of the safety and efficacy of Amifostine in leukemias.
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PMID:Amifostine does not inhibit the toxic effects of anthracycline derivates or mitoxantrone on MDR tumor cell lines. 1169 2

Anthracyclines are powerful cytotoxic agents, used as first-line treatment of leukemias and many other tumors, but host-tissue toxicity is their main dose-limiting factor. However, their therapeutic effects depend not only on the toxicity, hence on the dose, but also on drug resistance. Among the mechanisms that can account for cell sensitivity to anthracyclines, there is an overexpression of drug transport proteins, like the transmembrane P-glycoprotein (PGP), the multidrug- resistance-related protein (MRP) and the lung-resistance-related protein (LRP). Attempts to reduce the toxicity of chemotherapeutic agents without affecting their efficacy have been made using liposomal anthracyclines or cytoprotective agents, as Amifostine. The aim of this study was to evaluate and compare the toxic effects of Daunorubicin, in normal or liposomal formulation, used in combination with WR1065, the active metabolite of Amifostine, against normal and tumor cells. In conclusion these data show that the preincubation with WR-1065 does not inhibit the drug toxic effect on blast cells and on tumor cell lines, independently by their multidrug resistance phenotype, but has a cytoprotective effect on stem cells causing a drug cytotoxicity reduction of 10-20%. This advantage is even higher using the liposomal formulation of DNR. Therefore, Amifostine can offer a chance of protecting normal cells from the toxicity of anthracyclines, in normal or liposomal formulation. The combination of liposomal anthracyclines with Amifostine can confer further advantages in management of leukemic patients, especially the elderly where treatment toxicity is a main problem. These patients may be candidates for alternative therapeutic strategies and the combination of DNX and Amifostine is an attractive treatment for these cases where a low nonhematological toxicity is required.
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PMID:Effect of amifostine on the cytotoxicity of daunorubicin and daunoxome in tumor and normal cells. 1600 Nov 70