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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three new tissue culture cell lines, CHP-100, CHP-126, and CHP-134, have been established from explant cultures of human neuroblastoma. The cell lines have been characterized with respect to morphology, chromosomes constitution, growth, neural enzyme content, and their ability to grow in nude mice. The cells grow as dense masses comprised of fibroblast-or neuroblast-like cells with small processes. The cell lines differ in their neural enzyme acitivity. The chromosomal content of the 3 cell lines is near diploid, and all are capable of forming tumors in nude mice. The morphological findings indicate that the cells in culture resemble those found in the tumor, and the enzyme activities are consistent with those of nervous tissue. This the morphological, biochemical, and tumorigenic properties confirm that the 3 cell lines are neoplastic cells of neural origin.
Cancer Res 1976 Sep
PMID:Establishment and characterization of human neuroblastoma cell lines. 1 79

The objective of this investigation was to throw light on the biological behavior and metabolic regulation of hepatic enzymes of the nonoxidative branch of the pentose phosphate pathway. The activities of transaldolase (EC 2.2.1.2) and trasketolase (EC 2.2.1.1) Were compared in biological conditions that involve modulation of gene expression such as in starvation, in differentiation, after partial hepatectomy, and in a spectrum of hepatomas of different growth rates. The enzyme activities were determined under optimal kinetic conditions by spectrophotometric methods in the 100,000 X g supernatant fluids prepared from tissue homogenates. The kinetic properties of transaldolase and transketolase were similar in normal liver and in rapidly growing hepatoma 3924A. For transaldolase, apparent Km values of 0.13 mM (normal liver) and 0.17 mM (hepatoma) were observed for erythrose 4-phosphate and of 0.30 to 0.35 mM for fructose 6-phosphate. The pH optima in liver and hepatoma were at approximately 6.9 to 7.2. For the transketolase substrates, ribose 5-phosphate and xylulose 5-phosphate, the apparent Km values were 0.3 and 0.5 mM, respectively, in both liver and hepatoma. A broad pH optimum around 7.6 was observed in both tissues. In organ distribution studies, enzyme activities were measured in liver, intestinal mucosa, thymus, kidney, spleen, brain, adipose tissue, lung, heart, and skeletal muscle. Taking the specific activity of liver as 100%, transaldolase activity was the highest in intestinal mucosa (316%) and in thymus (219%); it was the lowest in heart (53%) and in skeletal muscle (21%). Transketolase activity was highest in kidney (155%) and lowest in heart (26%) and skeletal muscle (23%). Starvation decreased transaldolase and transketolase activities in 6 days to 69 and 74%, respectively, of those of the liver of the normal, fed rat. This was in the same range as the decrease in the protein concentration (66%y. In the liver tumors, transaldolase activity was increased 1.5- to 3.4-fold over the activities observed in normal control rat liver. Transketolase activity showed no relationship to tumor proliferation rate. In the regenerating liver at 24 hr after partial hepatectomy, the activity of both pentose phosphate pathway enzymes was in the same range as that of the sham-operated controls. In differentiation at the postnatal age of 5, 12, 23, and 32 days, hepatic transaldolase activities were 33, 44, 55, and 72%, respectively, of the activities observed in the 60-day-old, adult male rat. During the same period, transketolase activ-ties were 18, 21, 26, and 55% of the activities observed in liver of adult rat. The demonstration of increased transaldolase activity in hepatomas, irrespective of the degree of tumor malignancy, differentiation, or growth rate, suggests that the reprogramming of gene expression in malignant transformation is linked with an increase in the expression of this pentose phosphate pathway enzyme...
Cancer Res 1976 Sep
PMID:Behavior of transaldolase (EC 2.2.1.2) and transketolase (EC 2.2.1.1) Activities in normal, neoplastic, differentiating, and regenerating liver. 1 80

L-Asparagine synthetase appears in serum approximately 7 days after the s.c. implantation of 1 X 10(5) cells of Leukemia 5178Y/AR (resistant to L-asparaginase) and increases in activity as the neoplasm grows and metastasizes. The principal source of the enzyme is the primary tumor. After intravranial inoculation of tumor, the rate of leakage of the enzyme is more pronounced than when the subcutaneous, intramuscular, or intraperitoneal routes are used. 1-(2-Chloroethyl)-3-cyclohexyl-1-nitrosourea (NSC 79037), a nitro-sourea effective in the palliation of L5178Y/AR, temporarily halts the influx of enzyme into the blood stream, as does surgical excision of the s.c. tumor nodules. Treatment of mice with L-asparaginase within 24 hr of inoculation of the tumor markedly augments both tumor growth and the rate of penetration of L-asparagine synthetase into the circulation. Several other L-asparagine synthetase into the circulation. Several other L-asparaginase-resistant tumors also were found to spill L-asparagine synthetase into the serum, but the correlation between this phenomenon and the specific activity of the enzyme in homogenates of the tumor was imperfect.
Cancer Res 1976 Sep
PMID:L-Asparagine synthetase in serum as a marker for neoplasia. 1 81

Previous studies indicating the importance of catecholamine metabolism in neuroblastoma were briefly reviewed. Metabolic pathways were presented showing how the major urinary metabolites 3-methoxy-4-hydroxymandelic acid (VMA) and 3-methoxy-4-hydroxy-phenylacetic acid (HVA) are formed from norepinephrine and from dopamine plus 3,4-dihydroxyphenylalanine (DOPA), respectively. For 289 neuroblastoma patients at the time of diagnosis, the urinary excretion of VMA was significantly elevated in 75%, and HVA was elevated in 80%. Periodic assay of these metabolites during the course of the disease revealed that the excretion trends were of prognostic value with 80-90% reliability. By contrast, when the excretion in only the initial urine specimens was considered, the survival rate was the same for patients with normal, and with significantly elevated, excretion. Review of the results of tracer studies aimed at elucidating the in vivo metabolic origins of the urinary metabolites suggested that a) in neuroblastoma, the catecholamines were largely inactivated by intracellular metabolism in the tumor cells; b) there was excess production and excretion of the norepinephrine precursors, DOPA and dopamine; and c) in the tumors of most neuroblastoma patients, the initial enzyme in catecholamine synthesis, tyrosine hydroxylase, had an activity comparable with that in normal adrenal glands. The importance of the metabolism of catecholamines in patients with neuroblastoma was stressed: a) The excretion of elevated levels of urinary catecholamine metabolites were useful in diagnosis and in following the course of the disease, and b) study of the catecholamine metabolism in these patients permitted examination of possible relationships between the activity of the enzymes involved in catecholamine synthesis and the malignancy of this tumor.
J Natl Cancer Inst 1976 Sep
PMID:Catecholamine metabolism in neuroblastoma. 1 Apr 50

The influence of hyperthermia (42.5 degrees C) on the viability and morphology of L1A2 ascites cells incubated at various pH levels (6.4-7.2) was studied. In contrast to unheated cells, increased extracellular acidity in hyperthermically treated tumor cells was associated with markedly reduced viability of the tumor cells exposed to hyperthermia. The cells heated at neutral pH underwent ultrastructural nuclear changes; the most prominent were the appearance of filamentous bundles and increased perichromatin granules. The cells heated under more acid conditions had an increased lysosomal activity and intense cell lysis resulting in lethal damage to the entire cell population within 6 hours after treatment. The active mechanism was not clear, but cell membrane lesions combined with the increased lysosome activity seemed of major importance in the mechanism of heat-induced damage to tumor cells kept in an acid milieu.
J Natl Cancer Inst 1976 Jun
PMID:Influence of extracellular pH on the viability and morphology of tumor cells exposed to hyperthermia. 1 50

Malignant neoplasms of endocrine tissues represent almost half of the cancers diagnosed clinically in the United States, and many of these respond to hormonal therapies. Estrogen-induced testicular Leydig cell tumors in the mouse would seem to represent a realistic model for the laboratory investigation of this significant group of cancers. Data accumulated over the past few years clearly show that the Leydig cell is a target tissue for estrogens. Administering large doses of estrogen results in a reduction of enzymes converting progesterone to testosterone and induces a transient, but quantitatively very significant, synthesis of DNA in the Leydig cells of tumor-susceptible strains of mice. Neither of these actions of estrogen is mediated via the hypophysis. It has been demonstrated that the Leydig cells have specific protein receptors in their cytoplasm that bind estrogens and transport them to the nucleus where they are also bound. The genetic composition of the Leydig cells themselves is extremely important for the development of tumors. An adequately functioning pituitary gland is also essential for tumor formation. Confining the testes to the abdomen results in enzyme changes similar to those produced by estrogen administration and significantly augments the development of Leydig cell tumors. Once tumors form they frequently are dependent for their continued growth on estrogenic stimulation and/or on a functioning hypothysis. Regressed tumors may remain dormant for many months only to resume progressive growth when placed in and adequate hormone environment.
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PMID:Estrogen-induced Leydig cell tumor in the mouse: a model system for the study of carcinogenesis and hormone dependency. 1 51

A highly sensitive technique for isoferritin detection using 125I-labeled monospecific anti-human liver ferritin antibody for the identification of isoferritins after the analysis of small quantities of ferritin by isoelectric focusing in polyacryl-amide gels was applied to the study of renal, pancreatic, and colonic carcinomas. In all tumors studied, the isoferritin composition differed from that of the corresponding normal tissue; major isoferritins with pl more basic than those of the normal tissues were consistently detected. Composition of purified ferritin from metastases closely resembled the isoferritin composition of the primary tumors. Examination of the serum isoferritin profiles of four patients with cancers did not reveal the presence of any tumor-specific changes in isoferritins. It is suggested that the abnormality in tissue ferritins in the three human cancers studied is the synthesis of major isoferritins in the more basic range, rather than the appearance of tumor-specific isoferritins in the more acidic range.
Cancer Res 1976 Dec
PMID:Isoferritin composition of tissues and serum in human cancers. 1 86

Streptozotocin has been shown to induce the production of a variety of tumors in rats. The present report demonstrates that streptozotocin and 1-methyl-1-nitrosourea, a component of the streptozotocin molecule and a known carcinogen, stimulate the enzyme guanylate cyclase which catalyzes the production of guanosine 3',5'-monophosphate. At a maximal concentration of 3 mg/ml, these agents activated guanylate cyclase approximately 30-fold in liver, 20-fold in kidney, 15-fold in cerebellum. 15- to 30-fold in cerebrum, 4- to 20-fold inheart, 12-fold in brain stem, 10-fold in lung, and 2-fold in pancreas. Since recent evidence suggests a role for guanosine 3',5'-monophosphate in malignant transformation, the data may help explain the tumor-inducing capacity of these agents.
Cancer Res 1977 Jan
PMID:Activation of guanylate cyclase by streptozotocin and 1-methyl-1-nitrosourea. 1 88

The influence of intracellular pH (pHi) upon 5-fluorouracil (5-FU) uptake has been studied in slices of Walker 256 carcinosarcoma and rat liver. Alteration of pHi was achieved by the addition of either glucose alone or together with oxamic acid to the incubation medium. Results indicated that 5-FU uptake by the tumor slices was not dependent upon pHi, but was enhanced by the presence of glucose. Uptake of 5-FU by liver slices appeared to follow a pattern predictable from the pHi and the pK of the drug.
Cancer Treat Rep 1976 Jul
PMID:Dissociation of 5-fluorouracil uptake from intracellular pH in Walker 256 carcinosarcoma. 1 65

Rabbit antiserum to a tissue extract of human mucinous cystadenocarcinoma of the ovary reacted with tissue extracts of normal ovary and various ovarian malignancies, and ascitic or cystic fluids of ovarian origin by Ouchterlony double gel diffusion and precipitin inhibition techniques. The tumor-associated antigen(s) of mucinous cystadenocarcinoma, which were demonstrated by Ouchterlony double diffusion, were not present in tissue extract of pooled normal ovaries and cystic fluid of benigh tubo-ovarian cyst. An organ-associated tumor antigen as well as the type-specific tumor antigen may exist in mucinous cystadenocarcinoma of the ovary. The mucinous cystadenocarcinoma was not very immunologically different but was distinguishable from serous cystadenocarcinoma and other types of ovarian cancer by double gel diffusion. Precipitin-inhibition reactions demonstated that the adsorbed antiserum to human ovarian mucinous cystadenocarcinoma mixed with tissue extracts of dysgerminoma and serous cystadenocarcinoma, and ascitic fluid of papillary embryonal adenocarcinoma of the ovary could not eliminate the specific precipin line developed with tissue extract of mucinous cystadenocarcinoma.
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PMID:Detection of tumor-specific antigens in human mucinous cystadenocarcinoma of the ovary by immunodiffusion. 1 19


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