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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of cytotoxic hyperthermia on Ca2+ transport by intracellular, nonmitochondrial Ca2+ stores of the human colon cancer cell line, HT-29, was studied using cells permeabilized with saponin. Saponin treatment permitted equilibration of the cytosol with a defined extracellular medium consisting of an intracellular-like ionic composition, ATP and an ATP-regenerating system, and Ca2+/EGTA buffers to adjust the free [Ca2+]. Under the conditions employed, ATP-dependent Ca2+ uptake in saponin-permeabilized cells was demonstrated to be exclusively due to nonmitochondrial Ca2+ stores, e.g., endoplasmic reticulum or calciosomes. Heat treatment for 120 min at 44.5 degrees C sufficient to kill 80% of the cells inhibited ATP-dependent Ca2+ uptake by 50% in terms of rate and total Ca2+ accumulated. With cells made thermotolerant by either arsenite or heat treatment 24 h prior to challenge heating, ATP-dependent Ca2+ uptake was resistant to a second equivalent heat dose. Efflux of Ca2+ from saponin-permeabilized cells when measured at 37 degrees C was unaffected by a prior heat treatment (44.5 degrees C for 120 min).
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PMID:Cytotoxic hyperthermia and Ca2+ homeostasis: the effect of heat on Ca2+ uptake by nonmitochondrial intracellular Ca2+ stores. 237 83

The functional properties of mitochondria bound hexokinase are compared in two subpopulations of the HT29 human colon cancer cell-line: (1) the HT29 Glc+ cells, cultured in the presence of glucose, which are poorly differentiated and highly glycolytic and (2) the HT29 Glc- cells, adapted to grow in a glucose-free medium, which are 'enterocyte-like' differentiated and less glycolytic when given glucose (Zweibaum et al. (1985) J. Cell Physiol. 122, 21-28). The activities of hexokinase, phosphofructokinase-1 and pyruvate kinase are found to be twice as high in Glc+ cells when compared to Glc- cells. Besides, the respiration rate is decreased in Glc+ cells compared to Glc- cells. These results correlate with the higher glycolytic rate in Glc+ cells. In many tissues, it has been shown that the binding of hexokinase to the mitochondrial outer membrane allows a preferential utilization of the ATP generated by oxidative phosphorylation which, in turn, is activated by immediate restitution of ADP. In highly glycolytic cancer cells, although a large fraction of hexokinase is bound to the mitochondria, the existence of such a channeling of nucleotides is still poorly documented. The rates of glucose phosphorylation by bound hexokinase were investigated in mitochondria isolated from both Glc+ and Glc- cells either with exogenous ATP or with ATP generated by mitochondria supplied with ADP and succinate (endogenous ATP). Diadenosine pentaphosphate (Ado2P5), oligomycin and carboxyatractyloside (CAT) were used in combination or separately as metabolic inhibitors of adenylate kinase, ATP synthase and ATP/ADP translocator, respectively. Exogenous ATP appears to be 6.5-times more efficient than endogenous ATP in supporting hexokinase activity in the mitochondria from Glc+ cells and only 1.8-times cells. The rate of oxidative phosphorylation being higher in mitochondria from Glc- cells, hexokinase activity is higher in this model when ATP is generated by respiration. Furthermore, in Glc+ mitochondria, the adenylate kinase reaction appears to be an important source of endogenous ATP for bound hexokinase, while, in Glc- mitochondria, hexokinase activity is almost totally dependent on the ATP generated by oxidative phosphorylation. This result might be explained by our previous finding that mitochondria from Glc+ cells lack contact sites between outer and inner membrane, whereas numerous contacts were observed in mitochondria from Glc- cells (Denis-Pouxviel et al. (1987) Biochim. Biophys. Acta 902, 335-348).
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PMID:Study on ATP-generating system and related hexokinase activity in mitochondria isolated from undifferentiated or differentiated HT29 adenocarcinoma cells. 252 30

1. Carbohydrate metabolism was studied in HT29 human colon cancer cells cultured in a glucose free medium supplemented with 2.8 mM inosine (HT29ino cells) in comparison with standard HT29 cells grown in the permanent presence of glucose (HT29Glc + cells) and with HT29Glc- cells which are adapted to grow permanently without glucose. 2. Inosine allows the standard cells to grow when glucose is lacking but surprisingly stops the growth of HT29Glc- cells. 3-mercaptopicolinate, an inhibitor of PEP-carboxykinase, does not hinder HT29ino cells to grow, which shows that gluconeogenesis from aspartate or pyruvate is not essential. It suggests that enough carbohydrate is supplied by the ribose moiety of inosine. 3. While standard HT29Glc + cells are highly glycolytic, it is not the case of HT29ino or HT29Glc- cells when glucose is given for few hours. When glucose is present for 24 hr or more, glycolytic rate increases in HT29ino cells and glycogen accumulates. 4. It is found that the pattern of enzymes activities related to carbohydrate metabolism in HT29ino cells is closer to that of HT29Glc + cells rather than to that of HT29Glc- cells. However, phosphofructokinase-1 activity, measured with saturating concentration of Fru-2,6-diP, is significantly lower in HT29ino cells. 5. Binding rate of hexokinase to mitochondria is similar in the three cell-lines. However, in HT29Glc- cells, bound hexokinase easily utilizes ATP generated by the mitochondria. By contrast, in HT29Glc+ and HT29ino cells, bound hexokinase is much more active with exogenous ATP, suggesting a functional defect in the mitochondria from these two latter cells.
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PMID:Carbohydrate metabolism in HT29 colon cancer cells cultured in a glucose free medium supplemented with inosine. 252 33

Several in vitro chemosensitivity tests have been developed to select effective anticancer agents for individual cases. However, none of them is used routinely because of the low evaluability or the time consuming nature. We developed a new practical method which is simple, rapid, and applicable to fresh human tumors. The principle of the method is to measure the ATP content of cancer cells by bioluminescence after drug exposure. A linear relationship was observed between either the number of cells or their viability and light intensity. Four established human stomach cancer cell lines and five colon cancer cell lines were examined for their chemosensitivity with a test plate having 96 wells. A clear dose-dependent response was seen with almost all drugs tested in this study, and each cell line showed an identical response to drugs. For the clinical application, cancer cells taken from three human solid tumors were tested. In all cases, the chemosensitivity was clearly evaluable. This simple, rapid and sensitive method can be a good indicator for the determination of anticancer agents in cancer chemotherapy.
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PMID:[A new chemosensitivity test for cancer cells by measuring intracellular ATP content]. 323 Dec 5

A bioluminescence assay for ATP was adapted to human cancer cell lines and used to study the effect of anticancer drugs on malignant cell growth by following serial ATP measurements. Eleven drugs were tested against a colon cancer cell line (WiDR). Excellent correlation was observed between simultaneously performed soft-agar colony-forming assays and the ATP assay. In addition, cytostatic (growth inhibitory) drug effects could be distinguished from cytocidal (lethal) effects by using the ATP assay. Cytocidal drugs resulted in a reduction of ATP level below baseline levels, whereas cytostatic drugs merely yielded a reduction in the rate of increase in ATP level, i.e., slower growth. Such characterizations are not possible in colony-forming assays. Changes in ATP were correlated with the number of viable cells present. Drug concentration and duration of exposure both were important. Some drugs became cytocidal only when exposures longer than the customary 1 hour were used. The ATP assay has excellent potential as a simple, inexpensive, and rapid technique for new drug screening in cell lines, with classification of drug effects as cytostatic or cytocidal.
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PMID:ATP assay: ability to distinguish cytostatic from cytocidal anticancer drug effects. 346 95

Membrane-bound Na+/K(+)-ATPase purified from dog kidney outer medulla was solubilized with octaethylene glycol n-dodecyl ether (C12E8) and incubated with [3H]ouabain in the presence of NaCl. ATP and MgCl2 for 10 min at 0 degrees C. The resulting enzyme was separated, by high-performance gel chromatography executed at 0.2 degrees C. Mainly into its (alpha beta)2-diprotomer and alpha beta-protomer, which both bound stoichiometrically to [3H]ouabain. The amounts of ouabain that bound to the tissue itself and its microsomes could be estimated in the same way, as [3H]ouabain was found to bind only to the diprotomer and protomer they possessed. The amounts of ouabain that bound to them in the solubilized state were at least 5-times higher than those that did so when they were non-solubilized, suggesting that the surfactant rendered the enzyme accessible to ouabain. When the solubilized tissue (138 mg ml-1 wet tissue) was reacted with ouabain in the presence of 0.1 M NaCl and 4.8 mM MgCl2 for 10 min at 0 degrees C, maximal ouabain binding was attained in the presence of 18.3 microM [3H]ouabain, 1.2 mM ATP and 3 to 5 mg ml-1 C12E8, which was common to the outer medulla and human colon cancer cells. The present method enabled the pump number in protein and tissue samples in the range 7.2 x 10(-9) (purified pump) to 1.5 x 10(-12) (cancer tissue) mol/mg protein to be estimated within 2 h.
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PMID:Quantification of the Na+/K(+)-pump in solubilized tissue by the ouabain binding method coupled with high-performance gel chromatography. 749 49

The purpose of this study was to investigate the peculiarities of hormonal regulation of adenylate cyclase (AC) of blood lymphocytes in colorectal cancer patients and to compare these peculiarities with hormone sensitivity of AC of colorectal tumors and normal colonic mucosa. Basal and stimulated lymphocyte AC activity was studied in 51 healthy persons and 52 cancer patients (14 with colon cancer, 21 with rectal cancer and 17 with stomach cancer) aged 20-75 years. In 31 of 35 patients with colorectal cancer the AC activity was studied simultaneously in lymphocytes, tumor tissue and normal colonic mucosa. To evaluate basal and stimulated AC activity the measurement of c-AMP (Amersham kits) formed in the presence of ATP regenerating system was used. Basal and by VIP, pentagastrin and sodium fluoride stimulated AC activity in lymphocytes of gastrointestinal cancer patients was lower than in lymphocytes of healthy subjects of similar age. Stage dependence of the parameters under study was not found. There was a tendency for higher basal and stimulated lymphocyte AC activity in colon cancer patients as compared to stomach and rectal cancer patients. In colorectal cancer patients the peculiarities of lymphocyte AC reactions to stimulation were closer to those in tumor tissue but not to those in normal colonic mucosa. The reaction of lymphocyte AC to VIP and glucagon coincided more frequently with tumor AC reactions to the same hormones in case of hormone nonsensitive tumors. Thus, basal and stimulated lymphocyte AC activity in colorectal cancer patients was modified to some degree by tumor factors. Lymphocyte AC reactions to VIP and glucagon may be considered as indirect markers of hormone sensitivity of colonic tumors. Moreover, the probability of discovery of hormone nonsensitive tumors by this way is more reliable than hormone sensitive ones.
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PMID:Hormonal regulation of adenylate cyclase activity in circulating lymphocytes and its interrelationship with hormone sensitivity of tumor tissue in colorectal cancer patients. 761 78

Members of the carcinoembryonic antigen (CEA) family include CEA, non-specific cross reacting antigen (NCA), and biliary glycoprotein (BGP), and appear to function as cell adhesion molecules. Immunoprecipitation and subsequent gel electrophoresis of proteins from several colon cancer cell lines labeled with [gamma-32P]ATP, under conditions designed to detect ecto-kinase-catalyzed phosphorylation of cellular proteins, revealed that polyclonal anti-CEA antiserum recognized a 175-190 kDa phosphoprotein on the surface of colon cancer cells. The ability to detect this phosphoprotein did not correlate with CEA production, and immunoprecipitation studies suggested that the phosphoprotein is BGP. Phosphoamino acid analysis of the 175-190 kDa protein showed that it contained predominantly phosphotyrosine.
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PMID:Antiserum to carcinoembryonic antigen recognizes a phosphotyrosine-containing protein in human colon cancer cell lines. 768 8

Rhodamine 123 is a lipophilic cationic compound that is selectively taken up by cancer cell mitochondria. This compound is toxic to epithelial cancer cells in vitro and displays significant anticancer activity in vivo. However, the mechanism of action of rhodamine 123 in intact, actively metabolizing cell preparations is unknown. We have used 31P- and 13C-nuclear magnetic resonance spectroscopy to quantitatively characterize how rhodamine 123 affects the energetics of human colon cancer cells (HCT-116) and spontaneously immortalized normal epithelial cells (CV-1). Rhodamine 123 differentially altered the phosphorus and glucose metabolism of HCT-116 and CV-1 cells. 31P-nuclear magnetic resonance detected mitochondrial poisoning in the HCT-116 human colon cancer cell line in its early stages after selective uptake of rhodamine 123. When we compared administration of rhodamine 123 and [1-C13]glucose to administration of [1-C13]glucose alone in the HCT-116 cells, we noted a marked decrease in intracellular pH to 6.7 +/- 0.06 (mean +/- SD) units, a 2.2-fold increase in lactate production, and a 1.8-fold increase in glucose consumption after 10 h. In addition, we found a 2-fold rise in intracellular free magnesium 12 h after rhodamine 123 administration. These results suggest that when rhodamine 123 inhibits mitochondrial ATP production, it initially stimulates cytoplasmic glycolysis in an attempt to maintain cellular energy demands. The marked fall in intracellular pH and rise in intracellular free magnesium after administration of rhodamine 123 may inhibit activity of several glycolytic enzymes: this effect would inhibit cytoplasmic ATP generation and interfere with multiple cell enzymatic processes, leading to cell death. The CV-1 cells showed no change in intracellular pH, intracellular free magnesium, or magnesium-bound ATP levels over the 24-h period following rhodamine 123 administration. Rhodamine 123 also failed to alter glucose utilization and lactate production levels significantly in the CV-1 cells. These results prove the usefulness of 31P- and 13C-nuclear magnetic resonance spectroscopy for quantifying differing effects of rhodamine 123 on the high energy phosphate metabolism and glucose metabolism of HCT-116 and CV-1 cells.
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PMID:Quantitative differential effects of rhodamine 123 on normal cells and human colon cancer cells by magnetic resonance spectroscopy. 824 40

The formation of the glutathione S-conjugate of monochlorobimane (GSH-bimane) in human colon adenocarcinoma cells was identified by HPLC-fluorimetry and its transport from the cells was found to be temperature-sensitive, saturable and ATP-dependent. The apparent K(m) and Vmax values were 2.4 +/- 0.5 nmol GSH-bimane/10(6) cells and 0.5 +/- 0.1 nmol GSH-bimane/min per 10(6) cells, respectively. This active transport of GSH-bimane was inhibited by low micromolar concentrations of classical uncouplers of oxidative phosphorylation, namely carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP), carbonylcyanide m-chlorophenylhydrazone (CCCP) and 2,4-dinitrophenol (DNP). The efflux of GSH-bimane was competitively inhibited by chlorambucil (CMB) and 1-chloro-2,4-dinitrobenzene (CDNB), two other substrates of GST. This study demonstrates the presence and kinetic measurements of the glutathione S-conjugate export (GS-X) pump in human colon cancer cells, an export pump whose function has been implicated in the phenomenon of multidrug resistance.
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PMID:Active transport of glutathione S-conjugate in human colon adenocarcinoma cells. 895 Feb 21


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