Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

cis-Diamminedichloroplatinum(II) (CDDP) is the most active anticancer agent. It has been reported that intracellular accumulation of CDDP is an important step as a determinant for resistance to CDDP, which may be modulated by Na+, K(+)-ATPase activity. In this study, the significance of membrane Na+, K(+)-ATPase activity in the intracellular accumulation of CDDP were evaluated using human lung cancer cell lines. Na+, K(+)-ATPase was active in each cell line, not only non-small-cell lung cancer (NSCLC) but also in small-cell lung cancer (SCLC) cell lines. In NSCLC cell lines, there were significant correlations between Na+, K(+)-ATPase activities and intracellular accumulation of CDDP and the accumulation significantly decreased by ouabain, an inhibitor of Na+, K(+)-ATPase in each cell line. However, the correlation between enzyme activity and intracellular accumulation of CDDP were not significant in SCLC cell lines where sensitivity to CDDP was better than in NSCLC cell lines. These results suggest Na+, K(+)-ATPase are active in both NSCLC and SCLC cells, however, the importance of the enzyme as an active transporter of CDDP may be limited only to NSCLC cells. The mechanisms of intracellular accumulation may not be so important as a determinant of sensitivity to CDDP in SCLC cells.
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PMID:Significance of Na+, K(+)-ATPase on intracellular accumulation of cis-diamminedichloroplatinum(II) in human non-small-cell but not in small-cell lung cancer cell lines. 961 70

Cisplatin is a key drug in chemotherapy for lung cancer. It has been reported that intracellular accumulation of cisplatin is an important step as a determinant for resistance to cisplatin, which may be modulated by Na+, K+-ATPase activity. And it has been reported that isoproterenol, a beta-adrenoceptor agonist, enhances sensitivity to cisplatin in non-small cell lung cancer (NSCLC) cell lines. In this study, the effects of the selective beta1, beta2, and beta3-adrenoceptor agonists on membrane Na+, K+-ATPase activity and sensitivity to cisplatin were evaluated using human non-small cell lung cancer cell line. In the NSCLC cell line, sensitivity to cisplatin was improved by treatment with procaterol, a selective beta2-adrenoceptor agonist. Na+, K+-ATPase was activated and intracellular accumulation of cisplatin increased with the treatment. However, beta1 or beta3-adrenoceptor agonist did not modulate sensitivity to cisplatin or Na+, K+-ATPase activity. These results suggest that beta2-adrenoceptor may be one of the determinants for sensitivity to cisplatin in NSCLC. Exogenous beta2-adrenoceptor agonists may improve the antitumor effect of chemotherapy involving cisplatin.
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PMID:Selective beta2-adrenoceptor agonist enhances sensitivity to cisplatin in non-small cell lung cancer cell line. 1060 90

One of the cardinal questions in tumor immunology is the identification of antigenic structures in human tumors that are recognized by host immune system. A powerful new methodology for identifying human tumor antigens eliciting humoral immune response is SEREX (serological identification of antigen by recombinant cDNA expression cloning). Here, by using this method, a recombinant cDNA expression library from lung cancer was analysed and several new tumor antigens were isolated. Using the lambda-ZAP vector, cDNA expression library was constructed from lung cancer tissues of three patients including a moderately differentiated lung adenocarcinoma, a highly differentiated lung squamous cell carcinoma and a moderately differentiated lung adeno-squamous carcinoma. The primary library consisted of 0.8 x 10(6) recombinants. 33 positive clones encoding antigen genes were obtained after immunoscreening, and the nucleotide sequences of cDNA inserts were determined and analysed with DNASIS and BLAST softwares in EMBL and GenBank. These antigen genes included known genes, such as MAGE (melanoma antigen gene), vitiligo-associated protein VIT-1, fibronectin, Na-K-ATPase et al and unknown genes or ESTs. To characterize expression profile of these genes, antibodies in sera from 48 lung cancer patients and 48 health donors were assayed with three antigens (L-8, L-19, L-51) to screen specific and relative serum markers for lung cancer. The results show that positive rates in lung cancer patients are higher than in health donors. Our research indicates that some of these antigens may be related to lung cancer and may be valuable tumor markers in diagnosis of lung cancer.
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PMID:[Screening and identification of human lung cancer-related antigens]. 1200 91

Transport of xenobiotics and their metabolites by ATP-binding cassette (ABC) transporters particularly P-glycoprotein (Pgp) and the multidrug resistance associated protein (MRP1) has been extensively studied during last decade. Our recent studies demonstrate that RLIP76, a previously known GTPase-activating protein catalyzes ATP-dependent, uphill transport of anionic glutathione conjugates as well as of weakly cationic anthracyclines including doxorubicin (Adriamycin), a widely used drug in cancer chemotherapy. RLIP76 has inherent ATPase activity, which is stimulated by doxorubicin and glutathione conjugates. RLIP76 does not meet the criteria for classical ABC proteins such as MRP1 or Pgp, but similar to ABC proteins, it has two ATP-binding sequences, (69)GKKKGK(74) and (418)GGIKDLSK(425). Mutations in these sequences abrogate its ATP-binding, ATPase activity, and transport function. Purified RLIP76 when reconstituted in proteoliposomes mediates ATP-dependent saturable transport of doxorubicin and glutathione conjugates. Transfection of K562 cells with RLIP76 confers these cells resistance to doxorubicin and 4-hydroxynonenal. Cells enriched with RLIP76 also acquire resistance to radiation toxicity. RLIP76 also catalyzes the transport of physiologic ligands such as leukotrienes (LTC4) and the conjugate of 4-hydroxynonenal and glutathione. In some cells (e.g., erythrocytes and lung cancer cells), the majority of transport activity for Adriamycin and glutathione conjugates including LTC4 is accounted for by RLIP76. These studies strongly suggest that RLIP76-mediated transport of organic ions has physiological and toxicological relevance and that it may play an important role in the mechanism of drug resistance.
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PMID:RLIP76, a novel transporter catalyzing ATP-dependent efflux of xenobiotics. 1243 96

RLIP76 functions as an ATP-dependent transporter of amphiphilic chemotherapeutic drugs such as doxorubicin (DOX, adriamycin), as well as of glutathione-conjugates of endogenous electrophilic toxins such as 4-hydroxynonenal (4HNE). RLIP76 couples transport and ATP-hydrolysis with a 1:1 stoichiometry, making the ATPase activity of RLIP76 an excellent surrogate for its transport activity. Present studies were performed to determine the relationship of the RLIP76 ATPase activity with DOX and 4HNE resistance in a panel of 13 native human lung cancer cell lines. RLIP76 was purified from each cell line and homogeneity demonstrated by SDS-PAGE and amino acid composition analysis. Anti-RLIP76 antibodies were shown by Ouchterlony double immunodiffusion tests to be non-cross-reactive with any other proteins including P-glycoprotein (Pgp) or multidrug resistance associated protein (MRP). These antibodies completely immunoprecipitated ATPase activity of purified RLIP76 fractions, further confirming homogeneity of purified RLIP76. RLIP76 ATPase purified from NSCLC cell lines was about 2-fold more active than that from SCLC in the absence of the stimulator dinitrophenyl S-glutathione (206+/-47, n=7 vs. 94+/-22, n=6, nmol/min/mg protein, respectively), or in its presence (340+/-60, n=7 vs. 186+/-32, n=6, nmol/min/mg; p<0.01). Partial tryptic digest revealed a 44 kDa internal fragment of RLIP76 beginning at Thr-294 in NSCLC cell lines. This fragment was absent from all SCLC, suggesting the possibility that the activity of RLIP76 in SCLC and NSCLC is differentially regulated through post-translational modifications. Taken together, these findings suggest that RLIP76 activity is a general determinant of 4HNE and DOX resistance, and that its activity contributes to the drug-resistant phenotype of NSCLC.
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PMID:Role of RLIP76 in lung cancer doxorubicin resistance: I. The ATPase activity of RLIP76 correlates with doxorubicin and 4-hydroxynonenal resistance in lung cancer cells. 1252 36

A role for the SWI/SNF complex in tumorigenesis based on its requirement for retinoblastoma induced growth arrest and p53-mediated transcription and the appearance of tumors in SWI/SNF-deficient mice. In addition, Western blot data have shown that the SWI/SNF ATPase subunits cell, BRG1 and BRM (BRG1/BRM), are lost in approximately 30% of human non-small lung cancer cell lines. To determine whether loss of expression of these proteins occurs in primary tumors, we examined their expression in 41 primary lung adenocarcinomas and 19 primary lung squamous carcinomas by immunohistochemistry. These analyses showed that 10% of tumors show a concomitant loss of BRG1 and BRM expression. Moreover, patients with BRG1/BRM-negative carcinomas, independent of stage, have a statistically significant decrease in survival compared with patients with BRG1/BRM. This report provides supportive evidence that BRG1 and BRM act as tumor suppressor proteins and implicates a role for their loss in the development of non-small cell lung cancers.
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PMID:Loss of BRG1/BRM in human lung cancer cell lines and primary lung cancers: correlation with poor prognosis. 1256 96

The chronological changes in intracellular Ca(2+)concentrations ([Ca(2+)](i)) were analysed during heat-induced apoptosis in human lung cancer cell lines LK-2 (squamous cell carcinoma) and LU65A (large cell carcinoma). In LK-2 cells, increased [Ca(2+)](i) levels were maintained at levels between 250-350 nm 9 h after heat-shock. Treatment with BAPTA, an intracellular Ca(2+) chelator, prior to heat-shock, decreased the frequency of heat-induced apoptosis in LK-2, while thapsigargin, a selective endoplasmic reticulum Ca(2+)-ATPase inhibitor, did not change the number of apoptotic cells, regardless of the presence or absence of Ca(2+)-supplemented medium. In LU65A cells, treatment with BAPTA or thapsigargin did not alter the apoptotic rates. Western blotting demonstrated that, although expression of Bax and Bcl-2 were not changed by heat-shock, p53 expression was elevated in LK-2, but not LU65A cells. Immunohistochemistry showed that p53 was localized predominantly in the cytoplasms of LK-2 cells, suggesting that p53 protein is not functional in LK-2. Heat-shock also elevated activities of caspase-3, -8 and -9 in both cell lines. It is concluded that a temporal increase in [Ca(2+)](i) is the important initiating factor in hyperthermia-induced apoptosis in LK-2 cells and that, in these two lung cancer cell lines, apoptosis may occur through 'cross-talk' between p53-independent mitochondrial and death receptor pathways.
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PMID:Elevated levels of intracellular Ca2+ and apoptosis in human lung cancer cells given heat-shock. 1262 40

ATP-dependent transport of doxorubicin (DOX) by recombinant human RLIP76 has been demonstrated previously in reconstituted proteoliposomes. In the preceding communication, we demonstrated that the ATPase activity of RLIP76 was 2-fold higher in NSCLC as compared with SCLC, and it correlated with their inherent DOX resistance. Present studies were performed to determine whether greater ATPase activity of RLIP76 in NSCLC translated into greater RLIP76 mediated DOX transport, and to determine the overall contribution of RLIP76 toward total DOX transport. Consistent with the greater RLIP76 ATPase activity in NSCLC, DOX transport in artificial proteoliposomes reconstituted with purified RLIP76 from NSCLC was 1.8-fold greater than in SCLC. Anti-RLIP76 antibodies completely abrogated DOX transport in these RLIP76 proteoliposomes, whereas anti-MRP or anti-Pgp antibodies had no effect on transport. DOX transport studies in crude membrane vesicles from SCLC and NSCLC also showed a 2.1-fold higher rate of transport in NSCLC as compared with SCLC. Anti-RLIP76 IgG, which recognized only RLIP76 in crude extracts of both SCLC and NSCLC, inhibited 67+/-4% (n=12 cell lines) of total DOX transport in crude membrane vesicles from both SCLC and NSCLC. Inhibition of DOX transport by anti-MRP and anti-Pgp antibody was 35+/-7% (n=12) and 2+/-0.3% (n=12), respectively. The mixture of the three antibodies inhibited DOX transport by 95+/-3% (n=12). These studies demonstrate that DOX transport activity of RLIP76 is significantly greater in NSCLC as compared with SCLC, and that RLIP76 is the major DOX transporter in lung cancer cell lines.
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PMID:Role of RLIP76 in lung cancer doxorubicin resistance: II. Doxorubicin transport in lung cancer by RLIP76. 1263 60

The current study was designed to evaluate the effects of oral supplementation of the piperine on lung tumour initiation by orally applied benzo(a)pyrene (B(a)p). To evaluate the effects of orally supplemented piperine on lung tumour initiation by B(a)p, its effects on ATPase enzymes were first evaluated. Lung cancer bearing mice showed an increase in erythrocyte membrane and tissues ATPase enzymes (Na(+)/K(+)-ATPases, Mg(2+)-ATPases and Ca(2+)-ATPases). Na(+) K-ATPase and Mg-ATPase enzyme activities were decreased and calcium ATPase increased (P < 0.05) in erythrocyte membrane and tissues of lung cancer bearing animals compared with control groups. The elevation of these enzyme activities in membrane and tissues were indicative of the persistent deteriorating effect of B(a)p in cancer bearing animals. These enzyme activities were reversed to near normal control values in animals treated with piperine (50 mg/kg body weight). It is apparent that the beneficial effect of piperine is primarily exerted on the during initiation phase and post-initiation stage of B(a)p induced lung carcinogenesis. Overall, these data indicative that piperine has chemopreventive effects when administered orally on lung cancer bearing animals.
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PMID:Chemopreventive effect of piperine on modulating lipid peroxidation and membrane bound enzymes in benzo(a)pyrene induced lung carcinogenesis. 1518 54

The SMARCA4/BRG1 gene product is a component of the SWI-SNF chromatin-remodeling complex and regulates gene expression by disrupting histone-DNA contacts in an ATP-dependent manner. Inactivating mutations of the SMARCA4 gene, on chromosome arm 19p, are present in several human cancer cell lines, including cell lines derived from lung cancers. Interestingly, loss of heterozygosity (LOH) at 19p and absence of the SMARCA4 protein have been reported in lung tumors. To evaluate further the possible contribution of SMARCA4 gene inactivation to lung carcinogenesis, we performed a complete analysis of the SMARCA4 gene to search for (a) point mutations in all 35 coding exons, including an existing splicing variant and the intron-exon boundaries, and (b) abrogation of gene expression through promoter hypermethylation by using the methylation-specific polymerase chain reaction (MSP) assay. We selected genomic DNA from 20 lung primary tumors with LOH on 19p for the screening of point mutations and 10 lung cancer cell lines and 52 lung primary tumors for the MSP analysis. Through our mutational screening, we identified an in-frame and germ-line insertion of 24 bp in exon 4 whose biological relevance is unknown. This variant was not detected in the germ line of the 62 additional individuals analyzed, indicating it is not a common polymorphism. Moreover, two missense alterations were identified in the tumors of 2 patients, a somatic Gly1160Arg mutation and a Ser1176Cys mutation. Neither was present in the germ line of the 51 additional lung cancer individuals tested. Because these mutations lead to substitution of highly conserved amino acids, they may affect the ATPase function of the protein. Finally, no promoter hypermethylation was observed in any lung primary tumor or cancer cell line, indicating that this is not a major mechanism for SMARCA4 inactivation during lung carcinogenesis. In conclusion, our data revealed that somatic point mutations of the SMARCA4 gene are present in a small subset of lung tumors, although mutations affecting the ATPase domain may be a hot-spot for SMARCA4 gene inactivation. We cannot rule out that other mechanisms, such as complete or partial deletions of the SMARCA4 gene, are contributing to the loss of the SMARCA4 protein in lung cancer.
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PMID:Genetic and epigenetic screening for gene alterations of the chromatin-remodeling factor, SMARCA4/BRG1, in lung tumors. 1528 30


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