Abstract:
PURPOSE:Several studies have identified amino acid residues located on the hydrophobic side of the helix that forms transmembrane domain 6 (TM6) of the ABC transporter P-glycoprotein (Pgp) as being important for function. The purpose of this study was to determine if alterations to residues on the hydrophilic side could also affect function and to determine the extent to which altering the hydrophobic nature of residues on the hydrophobic side would impair the protein. METHODS:A full-length cDNA encoding wild-type Pgp1 from CHL cells was used as a template for site-directed mutagenesis. Eight different mutations, three on the hydrophilic side and five on the hydrophobic side, were prepared and transfected into drug-sensitive host cells. Wild-type transfectants served as controls. Drug resistance levels, RD50 values for cyclosporin A (CsA) and verapamil, iodoarylazidoprazosin (IAAP) photolabeling and verapamil-stimulated ATPase activity were evaluated. RESULTS:Substitution of any one of three amino acid residues on the hydrophilic side of TM6 disrupted function and led to alterations in drug resistance, CsA sensitivity, IAAP photoaffinity labeling, and in one case verapamil-stimulated ATPase activity. Replacement of a hydrophobic residue on the hydrophobic face of the helix with increasingly hydrophilic side-chains led to functional changes, the extent of which did not correlate with the degree of side-chain hydrophilicity. Finally, while the placement of a proline residue along either face of the helix had varying effects on function, in all cases its presence interfered with verapamil-stimulated ATPase activity. CONCLUSIONS:Taken together these results indicate that both faces of TM6 mediate Pgp1 function and that the expected conformational changes resulting from proline substitutions at a variety of locations within the helix can alter the protein's enzymatic activity.
journal_name
Cancer Chemother Pharmacoljournal_title
Cancer chemotherapy and pharmacologyauthors
Song J,Melera PWdoi
10.1007/s002800100354keywords:
subject
Has Abstractpub_date
2001-11-01 00:00:00pages
339-46issue
5eissn
0344-5704issn
1432-0843journal_volume
48pub_type
杂志文章abstract::The nephrotoxic interaction between cis-diamminedichloroplatinum (CDDP) and amikacin (AMI) was studied in rats. Following a single dose of CDDP (5 mg/kg i.v.), AMI (60 mg/kg s.c.) was given for 14 days. When given alone CDDP caused a 40% fall in the glomerular filtration rate (GFR), whereas AMI alone had no effect on ...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/BF00257319
更新日期:1988-01-01 00:00:00
abstract::A highly sensitive enzyme-linked immunosorbent assay (ELISA) for etoposide (EP) was developed, which is capable of accurately measuring as little as 40 pg EP/ml. Anti-EP sera were obtained by immunizing rabbits with EP conjugated with mercaptosuccinyl bovine serum albumin (MS.BSA) using N-[beta-(4-diazophenyl)ethyl]ma...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
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更新日期:1990-01-01 00:00:00
abstract::The clinical formulation of leucovorin (5-CHO-FH4) is a mixture of diastereoisomers with markedly different pharmacologic properties. Comparatively little information is available concerning the cellular pharmacology of reduced folate stereoisomers, due largely to the difficulty in preparing sufficient quantities of t...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/BF02897229
更新日期:1990-01-01 00:00:00
abstract::Reduced drug accumulation may be one reason for intrinsic drug resistance in chronic lymphatic leukemia of the B-cell type (B-CLL). Immunophenotyped leukemic human B-cells from 38 cases of B-CLL were characterized for P-glycoprotein (PGP) content. In all, 30 cases of B-CLL were additionally analyzed for further parame...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/BF00686038
更新日期:1994-01-01 00:00:00
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journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-009-1205-4
更新日期:2010-09-01 00:00:00
abstract::A phase I trial of indicine-N-oxide was carried out in 12 children with solid tumors and in 16 with leukemia. Doses of 5, 6, and 7.5 g/m2 were given parenterally as a 15-min infusion every 3 weeks. The maximum tolerated dose in patients with solid tumors was 7.5 g/m2 and the dose-limiting toxicity was myelosuppression...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/BF02897298
更新日期:1990-01-01 00:00:00
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journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-011-1781-y
更新日期:2012-04-01 00:00:00
abstract:PURPOSE:Our study was designed to evaluate the efficacy and safety of everolimus in patients with pre-treated metastatic gastric and esophagus cancers in a US-based population focusing on biomarker correlation. METHODS:Patients with advanced upper GI adenocarcinomas who progressed after 1-2 prior regimens received eve...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章,多中心研究
doi:10.1007/s00280-015-2744-5
更新日期:2015-07-01 00:00:00
abstract::The effects of BCNU, CCNU, methyl-CCNU, streptozotocin, and chlorozotocin on calmodulin activity were studied in vitro and in vivo. Preincubation of BCNU, CCNU, and methyl-CCNU with calmodulin produced a concentration-dependent inhibition of in vitro calmodulin activity expressed as stimulation of cyclic nucleotide ph...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/BF00434354
更新日期:1985-01-01 00:00:00
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journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-006-0238-1
更新日期:2007-02-01 00:00:00
abstract:PURPOSE:Based on the preclinical evidence of topoisomerase I (Topo-1) upregulation by mitomycin C(MMC) and decreased NF-kappaB activation by celecoxib, we evaluated combinations of irinotecan/MMC and irinotecan/MMC/celecoxib in patients with advanced solid malignancies. PATIENTS-METHODS:Initially, patients received MM...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-008-0826-3
更新日期:2009-05-01 00:00:00
abstract::When tumor cell density increases, the cytotoxic activity of certain anticancer agents, such as vincristine (VCR) and doxorubicin (DXR), progressively decreases. This phenomenon is termed the inoculum effect. Since VCR and DXR are less active in an acidic environment, we questioned whether the inoculum effects could h...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/BF00695987
更新日期:1992-01-01 00:00:00
abstract:BACKGROUND:Cetuximab and panitumumab are chimeric and fully human monoclonal antibodies, respectively, against epidermal growth factor receptor used in the treatment of metastatic colorectal cancer (mCRC). Incidence of documented infusion reaction (IR) is more common with cetuximab (all grades [g]: 15-21%, g 3/4: 2-5%)...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-009-1009-6
更新日期:2009-12-01 00:00:00
abstract:BACKGROUND:We investigated the efficacy and safety of 60, 120, or 240 mg of Z-360, which is a highly potent cholecystokinin2-receptor-selective antagonist, combined with gemcitabine in patients with metastatic pancreatic cancer. METHODS:Patients were randomly assigned in a 1:1:1:1 ratio to one of four treatment groups...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章,多中心研究,随机对照试验
doi:10.1007/s00280-017-3351-4
更新日期:2017-08-01 00:00:00
abstract:BACKGROUND:The cyclin-dependent kinase inhibitor flavopiridol increases irinotecan- and fluorouracil-induced apoptosis. We conducted a phase I trial of FOLFIRI + flavopiridol in patients with advanced solid tumors. DESIGN:FOLFIRI + flavopiridol were administered every 2 weeks. Based on sequence-dependent inhibition, f...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-010-1269-1
更新日期:2010-11-01 00:00:00
abstract:PURPOSE:Cisplatin and radiation therapy remain the current standard for treating locally advanced SCCHN. Novel treatment approaches are needed, especially in patients with human papilloma virus (HPV)-negative disease who have worse outcomes despite multimodality therapy. METHODS:Using our institutional review board ap...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-014-2584-8
更新日期:2014-11-01 00:00:00
abstract::cis-Diammine-1,1-cyclobutane dicarboxylate platinum II (CBDCA, JM8), an analogue of cisplatin showing reduced toxicity in preclinical studies, was evaluated in 60 patients. Doses were given initially every 3 weeks and escalated from 20 to 520 mg/m2. Following this, doses were given every 4 weeks and escalated from 300...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/BF00257742
更新日期:1982-01-01 00:00:00
abstract:PURPOSE:The aim of this study is to investigate whether cortisol inhibited cell proliferation and the expressions of lipoprotein lipase (LPL), a key enzyme involved in the energy metabolism in tumor cells, and vascular endothelial growth factor (VEGF), a potent angiogenic factor in the tumor, in cultures of OST cells, ...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-007-0492-x
更新日期:2008-03-01 00:00:00
abstract:PURPOSE:The combination of docetaxel, cisplatin and 5-fluorouracil (DCF) is a newly developed chemotherapy regimen for esophageal cancer. Severe neutropenia is dose-limiting toxicity of docetaxel and it is well known to be frequently occurred during DCF chemotherapy. This study aimed to investigate the relationship bet...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-020-04118-9
更新日期:2020-08-01 00:00:00
abstract:BACKGROUND:The pharmacokinetics and tissue distribution of photofrin II (PF) and its efficacy in sonodynamic therapy were studied in rats bearing AH130 solid tumors. MATERIALS AND METHODS:In order to find the optimum timing of the ultrasound exposure after administration of PF, the PF concentrations in plasma, skin, m...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-002-0523-6
更新日期:2003-02-01 00:00:00
abstract::New active drugs are needed for the treatment of primary brain tumors in both children and adults. S16020 is a cytotoxic olivacine derivative that inhibits topoisomerase II. The aim of the study was to determine its antitumor activity in athymic mice bearing subcutaneous medulloblastoma (IGRM33, 34, 57) and glioblasto...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-003-0584-1
更新日期:2003-05-01 00:00:00
abstract:BACKGROUND:In this phase II clinical trial, we evaluated the efficacy and safety of S-1 monotherapy in patients with previously treated advanced non-small-cell lung cancer (NSCLC). We also measured plasma concentrations of 5-fluorouracil (5-FU) and 5-chloro-2,4-dihydroxypyridine components of S-1 and examined correlati...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-011-1795-5
更新日期:2012-04-01 00:00:00
abstract:PURPOSE:RSR13, 2-[4-[2-[(3,5-dimethylphenyl)amino]-2-oxoethyl]phenoxy]-2-methylpropanoic acid monosodium salt, allosterically modifies hemoglobin to increase tumor pO(2), increases the effect of radiation in animal tumor models, and is in phase III clinical trials as an adjuvant to radiotherapy. Cisplatin and carboplat...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-003-0715-8
更新日期:2004-01-01 00:00:00
abstract:PURPOSE:Previous studies have shown that angiotensin peptides stimulate the proliferation of hematopoietic progenitors in vitro, promote survival after exposure to lethal irradiation as well as accelerate the recovery of white blood cells (WBC), i.e., lymphocytes, monocytes and neutrophils, and platelets. These changes...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-002-0509-4
更新日期:2003-02-01 00:00:00
abstract:PURPOSE:The prognosis of gastroesophageal cancer is poor, and current regimens are associated with limited efficacy. The purpose of this study was to explore the safety and preliminary efficacy of docetaxel, oxaliplatin plus capecitabine for advanced cancer of the stomach or the gastroesophageal junction (GEJ). Seconda...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章,多中心研究
doi:10.1007/s00280-015-2872-y
更新日期:2015-12-01 00:00:00
abstract:PURPOSE:Thymidylate synthase (TS) is one of the target molecules for the antitumor effects of fluoropyrimidine drugs. The cellular thymidylate synthase level is one of the determining factors for the antitumor activity of fluoropyrimidines. TYMS, which encodes TS, has been reported to possess 28-bp tandem repeat sequen...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-005-1018-z
更新日期:2005-11-01 00:00:00
abstract:PURPOSE:An isolated pelvic perfusion technique using multiple agents was used both in patients with unresectable recurrent pelvic neoplasms and as a preoperative therapy for advanced pelvic malignancy. METHODS:The technique consisted of vascular occlusion via transfemoral balloon catheters, circulation and drug infusi...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s002800050918
更新日期:1999-01-01 00:00:00
abstract:PURPOSE:The purpose of this investigation was to synthesize a series of carbonate and carbamate derivatives of 4-demethylpenclomedine (DM-PEN), the major plasma non-toxic metabolite of penclomedine (PEN) seen in patients. DM-PEN has been observed to be an active antitumor agent in mouse human xenograft tumor models and...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-009-0933-9
更新日期:2009-09-01 00:00:00
abstract:PURPOSE:Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Because HCC usually presents as an advanced disease and occurs in the background of liver cirrhosis, most patients are not suitable for treatment with curative intent, thus effective systemic chemotherapy is required. However, the ...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/s00280-005-0067-7
更新日期:2006-04-01 00:00:00
abstract::KW-2149, a new mitomycin C (MMC) derivative, inhibited the growth of murine P388 leukemia in vitro at 20-fold lower concentrations than those of MMC. KW-2149 was also effective in inhibiting the growth of MMC-resistant P388 (P388/MMC) cells. To elucidate these characteristics of KW-2149, its uptake and efflux were com...
journal_title:Cancer chemotherapy and pharmacology
pub_type: 杂志文章
doi:10.1007/BF00685871
更新日期:1993-01-01 00:00:00