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)

A comparative light microscopy, histoenzymological and ultrastructural study enabled the authors, in a case of invasive lobular carcinoma of the breast, to emphasise certain special morphological traits of this tumour type and to make a contribution to the understanding of its histogenesis. By light microscopy, the only special features of the case were the abundance of mucus secreting tumour cells in the perilobular infiltrating zones and in the stromal texture with marked perigalactophoric hyalinosis and active elastic neogenesis. From an ultrastructural standpoint, intralobular malignant zones contained epithelial type cells, rich in microfilaments and with numerous desmosomal junctions. Two other cell types were identified at the periphery of the lobules. On consisted of round cells with intracytoplasmic cavities filled with mucus (signet ring cells). This group, in common with the intralobular cells, contained abundant amounts of alkaline phosphatase. The other consisted of elongated "pseudo-fibroblastic" cells, rich in microfibrils and in granular ergastoplasm with secretion at points of contact of collagen and elastin. These cells showed marked ATPase activity. They no doubt represented "hybrid" cells, intermediate in terms of their morphology and enzyme activity between myoepithelial and epithelial cells. These findings would thus appear to offer arguments in favour of the double cell origin -- duct and myoepithelial -- of lobular carcinoma.
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PMID:[Histogenesis of lobular cancer of the breast. Histoenzymatic and ultrastructural study of a muciparous cell invasive epithelioma]. 625 29

A histochemical study has been done on a group of 18 hepatocarcinomas induced by aflatoxin. One hundred per cent, incidence of hepatocarcinomas is induced by feeding 5 p.p.m. aflatoxin for 6 weeks. The carcinomas were trabecular hepatocarcinomas with a mixed adenomatous pattern and showed considerable variation in histochemical reactions throughout the lesions. There was a patchy distribution of glycogen and glucose-6-phosphate and the membrane ATPase was present along much of the canalicular border of the cells but with an abnormal and tortuous pattern. Aniline hydroxylase was present in varying amounts in both trabecular and adenomatous carcinomas. It is concluded that the histological variants of hepatocarcinoma are all derived from hepatocytes, but no unique changes were observed related to the progress involved in malignant neoplasia. The observations form a basis for comparison with early lesions seen prior to the recognition of carcinoma.
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PMID:Histochemical studies of hepatocellular carcinomas in the rat induced by aflatoxin. 626 12

Hepatocellular neoplasms are known to differ in enzyme activity from the surrounding non-neoplastic liver. We have compared histochemically the enzyme activity of spontaneous hepatocellular tumors in mice with tumors induced by diethylnitrosamine and dieldrin. Some neoplasms had increased activity, others had decreased enzyme activity, yet other had the same activity as the surrounding liver. Alkaline phosphatase, glucose-6-phosphatase, succinic dehydrogenase and adenosine triphosphatase, as well as glycogen levels were studied. Carcinomas differed from adenomas in having elevated enzyme activity significantly more often than adenomas. However, the carcinomas showed elevated glycogen levels less frequently than adenomas. Histochemically, pulmonary metastases resembled the primary hepatocellular carcinomas from which they were derived. Tumors of dieldrin animals were notable in having increased activity of all the enzymes which we studied more frequently than tumors of diethylnitrosamine animals or of controls. Differences in enzyme activity between the three mouse strains were slight.
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PMID:Enzyme histochemical characteristics of spontaneous and induced hepatocellular neoplasms in mice. 629 95

Mitochondria-related Mg ATPase activity was assayed in lymphocytes isolated from the blood in 45 patients with epidermoid carcinomas of the larynx. Increased activity was found in 11 patients and normal or subnormal activity in the remaining cases. No correlation could be demonstrated between the magnitude or the spreading of the malignancy as recorded by the TNM classification and the ATPase activity. In 36 patients determinations were carried out repeatedly during a period from 6 to 20 months following therapy and after 3 years a final follow-up on all patients was done. All patients received high-voltage radiotherapy and in 7 patients additional partial or total laryngectomia was carried out, one patient had bilateral neck dissection. After radiotherapy the ATPase activity decreased significantly in 17 patients while it either remained normal or increased temporarily in the rest. No correlation was found between the course of the disease and the initial ATPase activity or the pattern of variation in ATPase activity following therapy. Contrary to what resulted from a preliminary study, it is concluded that determination of lymphocyte ATPase activity is of no diagnostic value in patients with laryngeal carcinoma, nor does it offer any prognostic help in determining which patients may relapse or develop metastatic disease.
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PMID:Lymphocyte ATPase activity in patients with carcinoma of the larynx. A follow-up study on 45 patients. 644 24

The structural and functional features of myoepithelial cells of the intact mammary gland, dyshormonal dysplasias and parenchymatous elements of lobular carcinoma of this organ were studied and compared for the purpose of the elucidation of controversial issue of the role of myoepithelial cells in histogenesis of mammary gland carcinoma. Some distinctive histological (selective staining with amido black--tannin acid), enzyme-chemical (high adenosine-triphosphatase activity), and ultrastructural (cytoplasmic fibrils with focal consolidations, pinocytic vesicles) features of myoepithelial cells were determined. The detection of similar properties in parenchymatous elements of lobular carcinoma facilitated the determination of the tumor cytogenetic profile and suggested the myoepithelial origin of a certain part of carcinoma parenchyma.
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PMID:[Participation of myoepithelial cells in the histogenesis of breast cancer]. 645 82

It has been shown that in the absence of inhibitors of oxidative phosphorylation, changes in fluorescence of 3',3'-diethylthiodicarbocyanine iodide (dis-C2-/5/) in a cell suspension of Ehrlich's ascites carcinoma reflect those in the transmembrane mitochondrial potential. Addition of glucose to the cells in the presence of respiratory inhibitors similar to rotenon induces oscillations in the membrane mitochondrial potential due to H+-ATPase that uses glycolytic ATP. The described changes in energy metabolism parameters are determined by impairment of the interplay between glycolysis and oxidative phosphorylation. The low rate of cytoplasmic NADH oxidation by tumor cell mitochondria favors the latter's accumulation by the cytoplasm and glycolysis inhibition. Pyruvate has been shown to be responsible for NADH oxidation and to remove glycolysis inhibition.
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PMID:[Kinetics of oxygen consumption, luminescence of pyridine nucleotides and the cyanine dye 3',3'-diethylthiodicarbocyanine iodide after energizing Ehrlich ascites carcinoma cells with glucose]. 715 Jul 43

A transgenic mouse model for hepatocarcinoma has been previously produced by targeting SV40 T-antigen expression to the liver. To evaluate the perturbation of cell death occurring during hepatocarcinogenesis, we examined the Fas-induced apoptosis on hepatocytes expressing T-antigen. Whereas anti-Fas antibody induced apoptosis in primary cultured normal hepatocytes, they imparted a weak cytotoxicity on primary cultured hepatocytes expressing T-antigen. This resistance of hepatic Fas-mediated apoptosis appears to result in an enhancement of a protective mechanism involving the protein kinase C signaling pathway rather than in a down-regulation of Fas-antigen expression. We further demonstrated that anti-Fas antibody does not have as efficient a lethal effect in T-antigen transgenic mice as in wild-type mice. The livers of transgenic mice injected with anti-Fas mAbs showed large intact regions with a few scattered apoptotic bodies: these regions strictly corresponded with carcinoma nodules, expressing high level of T-antigen. Our results describe a novel function for SV40 T-antigen which could contribute to viral pathogenesis by protecting infected cells against the host apoptotic defense mechanism.
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PMID:Fas-dependent apoptosis is impaired by SV40 T-antigen in transgenic liver. 756 65

It has been found that inhibition of mitochondrial ATPase in living thymocytes and Ehrlich ascites carcinoma (EAC) cells after incubation of cells with uncoupler, rotenone or cumene hydroperoxide, depends, in a large measure, on the inhibitor protein (IF1) action. Maximum inhibition (up to 70% of the oligomycin-sensitive ATPase activity) was found in the presence of the uncoupler in the incubation medium. Even when IF1 action was maximum, the residual ATPase activity caused marked ATP depletion in thymocytes, while in EAC cells other ATP-consuming processes prevailed. No inactive ATPase-IF1 complexes were found in intact thymocytes and EAC cells. The extent of inhibition of mitochondrial ATPase under oxidative stress was higher in thymocytes than in EAC cells and depended on cumene hydroperoxide concentration and duration of cell cellular ATP depletion. It is suggested that under certain experimental conditions IF1 can prevent cell death by slowing down the hydrolysis of cellular ATP.
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PMID:[Effect of protein inhibitors of mitochondrial ATPase in intact rat thymocytes and Ehrlich ascites carcinoma cells]. 757 68

Serum-free cultures of normal human buccal epithelial cells were transfected with a plasmid containing the SV40 T-antigen (SV40T) gene. Two major lines developed that showed extended lifespans (between 30 and 40 weeks) as compared with the controls (approximately 6 weeks). Continued growth through one or two crises generated several sublines. They expressed the epithelial marker keratin and also exhibited nuclear expression of SV40T. The lines showed abnormal karyotypes with both numerical and structural aberrations and variably responded to agents that normally inhibit growth and/or induce terminal differentiation, i.e. transforming growth factor-beta 1 and fetal bovine serum. One of the lines, termed SVpgC2a, developed into an apparently immortal line, since it had undergone more than 700 population doublings from over 2 years in culture. Further characterization of this line demonstrated its clonal origin, with integration of two copies of SV40T at the same site and the presence of both normal retinoblastoma and wild-type p53 proteins. This line showed high resistance to growth inhibition by transforming growth factor-beta 1 and serum similar to that shown by buccal carcinoma cell line SqCC/Y1. Neither SVpgC2a nor its parental lines were tumorigenic when injected into athymic nude mice, whereas the SqCC/Y1 cells induced tumors. The various lines with extended but finite lifespans, complemented by one immortalized line, which retained non-malignant properties upon extended culture, provide a battery of model systems that will be useful for studying mechanisms of human oral carcinogenesis.
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PMID:Characterization of human buccal epithelial cells transfected with the simian virus 40 T-antigen gene. 758 60

The overexpression of the P-glycoprotein, the MDR1 gene product, has been linked to the development of resistance to multiple cytotoxic natural product anticancer drugs in certain cancers and cell lines derived from tumors. P-glycoprotein, a member of the ATP-binding cassette (ABC) superfamily of transporters, is believed to function as an ATP-dependent drug efflux pump with broad specificity for chemically unrelated hydrophobic compounds. We review here recent studies on the purification and reconstitution of P-glycoprotein to elucidate the mechanism of drug transport. P-glycoprotein from the human carcinoma multidrug resistant cell line, KB-V1, was purified by sequential chromatography on anion exchange followed by a lectin (wheat germ agglutinin) column. Proteoliposomes reconstituted with pure protein exhibited high levels of drug-stimulated ATPase activity as well as ATP-dependent [3H]vinblastine accumulation. Both the ATPase and vinblastine transport activities of the reconstituted P-glycoprotein were inhibited by vanadate. In addition, the vinblastine transport was inhibited by verapamil and daunorubicin. These studies provide strong evidence that the human P-glycoprotein functions as an ATP-dependent drug transporter. The development of the reconstitution system and the availability of recombinant protein in large amounts due to recent advances in overexpression of P-glycoprotein in a heterologous expression system should facilitate a better understanding of the function of this novel protein.
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PMID:Purification and reconstitution of functional human P-glycoprotein. 762 47


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