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)

We isolated a paclitaxel-resistant cell line (KK47/TX30) from a human bladder cancer cell line (KK47/WT) in order to investigate the mechanism of and reversal agents for paclitaxel resistance. KK47/TX30 cells exhibited 700-fold resistance to paclitaxel and cross-resistance to vinca alkaloids and topoisomerase II inhibitors. Tubulin polymerization assay showed no significant difference in the ratio of polymerized alpha- and beta-tubulin between KK47/WT and KK47/TX30 cells. Western blot analysis demonstrated overexpression of P-glycoprotein (P-gp) and lung resistance-related protein (LRP) in KK47/TX30 cells. Drug accumulation and efflux studies showed that the decreased paclitaxel accumulation in KK47/TX30 cells was due to enhanced paclitaxel efflux. Cell survival assay revealed that verapamil and cepharanthine, conventional P-gp modulators, could completely overcome paclitaxel resistance. To investigate whether new synthetic isoprenoids could overcome paclitaxel resistance, we synthesized 31 isoprenoids based on the structure of N-solanesyl-N,N'-bis(3,4-dimethoxybenzyl)ethylenediamine (SDB), which could reverse multidrug resistance (MDR), as shown previously. Among those examined, trans-N,N'-bis(3,4-dimethoxybenzyl)-N-solanesyl-1,2-diaminocyclohexane (N-5228) could completely reverse paclitaxel resistance in KK47/TX30 cells. N-5228 inhibited photoaffinity labeling of P-gp by [(3)H]azidopine, suggesting that N-5228 could bind to P-gp directly and could be a substrate of P-gp. Next, we investigated structural features of these 31 isoprenoids in order to determine the structural requirements for the reversal of P-gp-mediated paclitaxel resistance, suggesting that the following structural features are important for overcoming paclitaxel resistance: (1) a basic structure of 8 to 10 isoprene units, (2) a cyclohexane ring or benzene ring within the framework, (3) two cationic sites in close proximity to each other, and (4) a benzyl group with 3,4-dimethoxy functionalities, which have moderate electron-donating ability. These findings may provide valuable information for the development of P-gp-mediated MDR-reversing agents.
 ...
PMID:Reversal of P-glycoprotein-mediated paclitaxel resistance by new synthetic isoprenoids in human bladder cancer cell line. 1235 58

P-glycoprotein (Pgp) participates in the export of numerous toxins, drugs, and physiological compounds. To examine the involvement of Pgp in smoke-induced oral cell insult, the effects of extracts of the mainstream tobacco smoke (TS) on Pgp were studied in an oral epidermal carcinoma cell line, OECM-1. TS was first extracted with cyclohexane (CTS) and the residues were further extracted with isopropanol (ITS). For comparison, cells were exposed to CTS and ITS at the concentrations according to their relative extraction yield. ITS but not CTS decreased the efflux of a Pgp substrate, rhodamine (Rh) 123, in a concentration- and time-dependent manner. The efflux was also decreased by co-exposure to CTS and ITS. However, immunoblot analysis revealed that the protein level of Pgp was not affected by ITS. Naphthalene, mainly detected in the ITS, decreased Rh 123 efflux. However, the efflux activity was not affected by benzo(a)pyrene and nicotine, which were present in the CTS and both extracts, respectively. Co-exposure to CTS in combination with ITS, naphthalene, or verapamil enhanced cell insult compared to single exposure. These results demonstrated that smoke and its constituent, naphthalene, diminished Pgp-mediated efflux. The reduction in Pgp function could be a stimulatory factor of TS-induced oral cell insult.
 ...
PMID:Suppressive effect of tobacco smoke extracts on oral P-glycoprotein function and its impact in smoke-induced insult to oral epidermal cells. 1913 10

Immunoconjugates of epirubicin were synthesized with monoclonal antibodies against the epidermal growth factor receptors, HER2/neu and EGFR, by creating a sulfhydryl-reactive epirubicin intermediate applying heterobifunctional succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC), which was introduced at alpha-monoamide groups of the epirubicin carbohydrate moiety. In parallel, N-succinimidyl-S-acetylthioacetate (SATA) was used to incorporate a sulfhydryl group into immunoglobulin at the terminal amine position of -lysine amino acid residues. Eprirubicin-SMCC-SATA-IgG immunoconjugates were produced by reacting epirubicin-SMCC and SATA-IgG at appropriate molar ratios. Epirubicin-(anti-HER2/neu) and epirubicin-(anti-EGFR) had greater potency against chemotherapeutic-resistant SKBr-3 mammary carcinoma than did epirubicin at epirubicin-equivalent concentrations. Epirubicin-(anti-HER2/neu) was more potent than epirubicin-(anti-EGFR), and a synergistic level of antineoplastic activity was detected with an epirubicin immunoconjugate 50/50 combination. Competitive P-glycoprotein inhibition with cyclosporin A or verapamil enhanced the potency of the epirubicin immunoconjugate 50/50 combination. Minor levels of antineoplastic activity were detected only with an immunoglobulin 50/50 combination of anti-HER2/neu and anti-EGFR. The investigations represent a potential strategy for enhancing the selective internalization, intracellular deposition, and antineoplastic potency of chemotherapeutics in multidrug-resistant neoplasias.
 ...
PMID:Dual potency anti-HER2/neu and anti-EGFR anthracycline immunoconjugates in chemotherapeutic-resistant mammary carcinoma combined with cyclosporin A and verapamil P-glycoprotein inhibition. 1948 May 61

A series of trans-3-oxospiro[(aza)isobenzofuran-1(3H),1'-cyclohexane]-4'-carboxamide derivatives were synthesized and profiled for NPY Y5 binding affinity, brain and CSF penetrability in rats, and susceptibility to human and mouse P-glycoprotein transporters in order to develop a PET ligand. Compound 12b exhibited an acceptable profile for a PET ligand, and [(11)C]12b was successfully utilized in clinical settings as a Y5 PET ligand.
 ...
PMID:Identification of positron emission tomography ligands for NPY Y5 receptors in the brain. 1967 69

A series of trans-3-oxospiro[(aza)isobenzofuran-1(3H),1'-cyclohexane]-4'-carboxamide derivatives were synthesized to identify potent NPY Y5 receptor antagonists. Of the compounds, 21j showed high Y5 binding affinity, metabolic stability and brain and cerebrospinal fluid (CSF) penetration, and low susceptibility to P-glycoprotein transporters. Oral administration of 21j significantly inhibited the Y5 agonist-induced food intake in rats with a minimum effective dose of 1mg/kg. This compound was selected for proof-of-concept studies in human clinical trials.
 ...
PMID:Discovery of trans-N-[1-(2-fluorophenyl)-3-pyrazolyl]-3-oxospiro[6-azaisobenzofuran-1(3H),1'-cyclohexane]-4'-carboxamide, a potent and orally active neuropeptide Y Y5 receptor antagonist. 1972 May 39