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)

FK-506, a novel immunosuppressive agent, was examined for its reversing effect on multidrug-resistant tumor cells. FK-506 at 3 microM completely reversed the resistance against vincristine (VCR) in vitro in VCR-resistant mouse leukemia P388 cells (P388/VCR). FK-506 also enhanced the cytotoxicity of VCR in Adriamycin(ADM)-resistant human ovarian cancer A2780 cells (AD10) and ADM-resistant human myelogenous leukemia K562 cells (K562/ADM) in vitro. FK-506 was also effective in modulating sensitivity to ADM in AD10 cells in vitro. FK-506 enhanced the chemotherapeutic effect of VCR in P388/VCR-bearing mice. When 20 mg/kg FK-506 was combined with 200 micrograms/kg VCR, a T/C value of 151% was obtained. Under the protocol used in this study, FK-506 was more potent than cyclosporin A (CsA) and verapamil. FK-506 inhibited [3H]azidopine binding to P-glycoprotein efficiently. The binding of VCR to K562/ADM plasma membrane was inhibited by FK-506 as effectively as by CsA. Moreover, the accumulation of VCR in AD10 cells was increased by FK-506 as efficiently as that of CsA and verapamil. These results indicate that FK-506 directly interacts with P-glycoprotein like CsA and verapamil, inhibits the active efflux of vincristine from resistant cells, increases the vincristine accumulation in resistant cells, and thus overcomes multidrug resistance in vitro and in vivo.
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PMID:Reversal of multidrug resistance by an immunosuppressive agent FK-506. 137 Jul 65

A human macrophage-colony-stimulating-factor (M-CSF) gene inserted into an expression vector (pRc/CMV-MCSF) was transfected into multidrug-resistant (MDR) human ovarian cancer cells (AD10) to induce secretion of human M-CSF into the medium. The M-CSF level in the culture medium of the transfected cells reached 100 ng/ml after 7 days, and the ability of the cells to secrete M-CSF was stable for at least 3 months. Transfection of the M-CSF gene did not result in any change in expression of MDRI (P-glycoprotein), proliferation or chemosensitivity of the cells from those of the parent cells. There was also no difference between the transfected and the parent cells in susceptibility to NK cell- or interleukin-2-activated killer-cell-mediated cytotoxicity. Human blood monocytes that had been incubated for 4 days in medium with the culture supernatant of MH-AD10 cells exhibited higher ADCC activity than untreated monocytes against MDRI-positive cancer cells. This effect of the supernatant of AD10 cells was completely abolished by its treatment with a monoclonal anti-M-CSF antibody (MAb). When transfected human MDR cells were injected into nude mice, an inverse correlation was seen between the ability of the cells to produce M-CSF and their tumorigenicity. Thus, gene modification of MDR cancer cells seems hopeful as a therapeutic method for enhancing anti-MDRI-MAb-dependent macrophage-mediated cytotoxicity against human MDR cancer cells.
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PMID:M-CSF gene transduction in multidrug-resistant human cancer cells to enhance anti-P-glycoprotein antibody-dependent macrophage-mediated cytotoxicity. 810 Aug 9

We have studied the effects of a novel derivative of apovincaminic acid ester, VA-033, on the resistance of tumors to chemotherapeutic agents. VA-033 increased the sensitivity of drug-resistant cell lines (P388/VCR, P388/ADM, AD10, and K562/ADM) to adriamycin or vincristine. The potency of VA-033 was stronger than verapamil. The drug lengthened the survival time of the P388/VCR-implanted mice treated with vincristine. VA-033 increased the intracellular accumulation of vincristine in the tumor cells, and the photolabeling of P-glycoprotein by [3H]azidopine was inhibited by VA-033. VA-033 showed a slight inhibitory effect on the L-type Ca2+ current in the ventricular myocytes, and had less effect on the cardiovascular parameters such as blood pressure, contractile force and atrio-ventricular conduction time than verapamil when administered systemically in the dog. These results suggest that VA-033 may become a beneficial compound as a modifier to the neoplastic cell resistant to multidrugs.
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PMID:Overcoming of multidrug resistance by VA-033, a novel derivative of apovincaminic acid ester. 920 May 66

In the present study, we examined the effect of interleukin-2 (IL-2) gene transfer into multidrug resistance (MDR) cancer cells on the therapeutic efficacy of MRK16. Human MDR ovarian cancer cells, AD10, were transduced with a bicistronic IL-2 retrovirus, Ha-IL2-IRES-Neo. The G418-resistant population, IL2-AD10, secreted IL-2 into the culture supernatant and did not form a tumor mass in nude mice. The IL2-AD10 cells were more susceptible to the cytotoxicity of murine spleen cells than AD10 cells in vitro. For examination of the effect of IL-2 gene transfer on the antitumor activity of MRK16 against P-glycoprotein-positive tumors, IL2-AD10 cells were co-transplanted s.c. with AD10 cells into nude mice in a ratio of 1:3, and the mice were treated with MRK16 on days 2 and 7. MRK16 markedly inhibited the growth of AD10 cells mixed with IL2-AD10 cells under conditions (0.3-1 microgram/body) where it showed only marginal effects on the growth of AD10 tumors. These findings suggest that IL-2 gene transfer potentiates the antitumor activity of MRK16 against MDR tumors.
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PMID:Combination therapy with antibody and interleukin-2 gene transfer against multidrug-resistant cancer cells. 943 86

Membrane and membrane-associated proteins are rich in known or potential pharmaceutical drug targets for carcinogenesis. In order to systemically analyze membrane proteins of human breast cancer, we isolated membrane from MCF-7 cells by sequential extraction by washing with three different buffers, namely, phosphate buffer (5 mM, pH 8.0), Tris (40 mM, pH 9.5), and sodium carbonate (100 mM pH 11). The extracted proteins were separated by two-dimensional gel electrophoresis (2-DE) using cup-loading and were then analyzed by peptide mass fingerprinting (PMF). A total of 137 spots from the gels of the three procedures were successfully identified. They corresponded to 79 distinct proteins. Among them, 22 exclusive proteins belonging to each washing procedure were also found, including P-glycoprotein, endoplasmin, Stress-70 protein, ADAM 10, protein disulfide isomerase, and glutamate receptor. These results indicate phosphate buffer to be the most beneficial for enrichment of peripheral membrane proteins, and sodium carbonate is beneficial for the presentation of integral membrane proteins but usually with poor resolution. The reference maps and identified proteins will serve as a basis for the further investigation of breast cancer, especially the proteomic comparison among different cell types of breast cancer, or among the different stages in the drug interfering process of the MCF-7 cell line.
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PMID:Membrane protein analysis of human breast cancer cell line MCF-7 by different membrane washing methods. 1870 47