Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Various lectins were found to induce tyrosine aminotransferase in H-35 rat hepatoma cells grown in monolayer culture. Wheat germ agglutinin gave a maximal induction of tyrosine aminotransferase 6 hours after its addition. The induction time course was similar to that elicited by insulin. Fourteen micrograms of wheat germ agglutinin per milliliter gave half-maximal enzyme induction and 50 micrograms per milliliter gave the maximal response. The induction of tyrosine aminotransferase by wheat germ agglutinin was additive with the induction by either dexamethasone or dibutyryl adenosine 3',5'-monophosphate, but was not additive with the tyrosine amino transferase induction by insulin. Wheat germ agglutinin also mimicked insulin in the inhibition of cellular protein degradation in the absence of serum. The insulin-like effects of lectins should be considered in lectin-mediated manipulations such as agglutination.
 ...
PMID:Lectins mimic insulin in the induction of tyrosine aminotransferase. 611 28

Concanavalin A added to monolayer cultures of Reuber H-35 hepatoma cells caused a rapid inactivation of tyrosine aminotransferase (L-tyrosine:2-oxoglutarate aminotransferase, E.C. 2.6.1.5) and loss of reactivity with antibody against the native, dimeric enzyme. Analysis of treated cells with an antibody raised against carboxymethylated, denatured enzyme showed that the inactivated enzyme was reactive with this reagent, which does not react with the native enzyme. Subsequent addition of alpha-methyl-D-mannopyranoside to remove concanavalin A restored both enzyme activity and reactivity to antibody against native enzyme. After long-term treatment with concanavalin A, the restored enzyme levels were significantly higher than in controls treated with the sugar but not the lectin. Analysis of the turnover of the enzyme by two methods revealed that the rate of its degradation is reduced about 2-fold in concanavalin A-treated cells. Treatment with H-35 cells with concanavalin A thus effects an alteration in conformation of tyrosine aminotransferase, rendering it somewhat less sensitive to intracellular degradation.
 ...
PMID:Concanavalin A alters the turnover rate of tyrosine aminotransferase in cultured hepatoma cells. 612 18

When rat hepatoma cells (HTC and R117-21B), treated with concanavalin A (conA) at 37 degrees C, were scraped from plastic culture dishes with a silicone-rubber policeman, the cell membranes were broken and the cytoplasm was released. This phenomenon was also observed in cells treated with conA at 4 degrees C, even though it took a longer time to show the same effect. The effect of 10 micrograms/ml of conA on the release of the cellular proteins reached a plateau when the treatment was carried out at 37 degrees C. Ninety percent of this effect was abolished by 10 mM of alpha-methyl-D-mannoside. The effect was completely nullified by 100 mM. At 4 degrees C, however, even 100 mM of this sugar could not abolish this effect. The apparent decrease in the cellular proteins with conA after scraping was observed not only in the logarithmic phase, but also in the stationary phase of cell growth. The breakdown of plasma membranes with conA eventually caused decrease in tyrosine aminotransferase activity, even though the lectin induced the enzyme activity in cultured cells.
 ...
PMID:The release of cytosolic proteins from cells treated with concanavalin A during scraping from plastic culture dishes. 613 87

By making use of the structural change of the sugar chains of liver gamma-glutamyl transpeptidase associated with malignant transformation, a new method has been developed to distinguish human serum gamma-glutamyl transpeptidase associated with primary hepatoma from that of non-hepatoma patients. In principle, the method consists of affinity chromatography of the desialylated serum enzyme on a Phaseolus vulgaris erythroagglutinating lectin agarose column.
 ...
PMID:Application of a Phaseolus vulgaris erythroagglutinating lectin agarose column for the specific detection of human hepatoma gamma-glutamyl transpeptidase in serum. 614 47

The adenosine deaminase-binding protein has previously been localized to the cell surface of human fibroblasts (Andy, R. J., and Kornfeld, R. (1982) J. Biol. Chem. 257, 7922-7925). In this study we examine the biosynthesis of binding protein in human fibroblasts, human hepatoma HepG2 cells, and a human kidney tumor cell line. Binding protein immunoprecipitated from radioiodinated detergent-extracted fibroblast membranes has a molecular weight of 120,000 when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An additional band of Mr 100,000 is also present which we believe is a result of proteolysis of the 120,000 band. Purified soluble kidney binding protein has an Mr of 112,000. Binding protein from fibroblasts pulse-labeled with [35S]methionine for 15 min migrates as a 110-kDa band on sodium dodecyl sulfate-polyacrylamide gels. Within 30-60 min of chase, the intensity of the 110-kDa band is diminished, and a 120-kDa band has appeared. Binding protein reaches the cell surface of fibroblasts within 30-60 min of chase. The same results are obtained with the other cell lines studied. Thus, binding protein is initially synthesized as a precursor of 110 kDa which chases into a 120-kDa mature form. The shift of 10 kDa is probably due to processing of its oligosaccharide chains since soluble kidney-binding protein contains 7-9 complex N-linked chains. Upon endoglycosidase H treatment, the 110,000 precursor shifts to a Mr of 89,000 while the 120,000 mature band shifts to 115,000, consistent with the presence of 7-9 high mannose chains on the precursor and 1-2 high mannose chains on the mature form. These results and the presence of complex N-linked chains on binding protein were confirmed by lectin affinity chromatography of glycopeptides derived from [2-3H]mannose-labeled binding protein. Analysis of [6-3H]glucosamine-labeled binding protein indicates the presence of 1 sialic acid residue per chain.
 ...
PMID:Biosynthesis of the adenosine deaminase-binding protein in human fibroblasts and hepatoma cells. 614 21

Papain-solubilized tumour-specific antigens from the aminoazo dye-induced rat hepatoma D23 were purified by a combination of lectin affinity and immunoadsorbent column chromatography. Isolated antigens were radio-iodinated using three procedures and analysed for their reaction with specific antibodies in syngeneic immune sera by double-antibody co-precipitation tests and by the rebinding of labelled antigens to specific and non-relevant antibodies immobilized on Sepharose-4B. Soluble hepatoma D23-specific antigens were labile to radiolabelling, and for optimal retention of serological reactivity it was necessary to protect the antigenic determinant by performing the chloramine T method of iodination with antigen bound to the immunoadsorbent followed by elution from the solid phase with 3M NaSCN. Immunoadsorption chromatography indicated that one consequence of radiolabelling hepatoma D23-specific antigen with 125I was a reduction in the affinity of the labelled antigen for its syngeneic specific antibody.
 ...
PMID:Radioiodination of rat hepatoma-specific antigens and retention of serological reactivity. 615 64

Microheterogeneity of alpha-fetoprotein (AFP) present in the sera of 76 patients was studied by lectin affino-immunoelectrophoresis. Seventeen patients had benign liver disorders and the remaining 59 patients were treated for primary or secondary liver cancer or yolk sac tumour. By means of Con A, AFP was divided into two variants, while lentil lectin (LCA) made it possible to separate AFP in three variants. In some patients the relative concentrations of Con A and LCA AFP variants were similar; these patients were believed to produce AFP of the same 'profile'. Fourteen AFP profiles were observed by estimation of the area enclosed by precipitates corresponding to respective AFP variants. It was also possible to estimate the AFP profile on the basis of a simple visual analysis of the electrophoretic plates. The obtained results indicate that the AFP profiles of patients with cancer were variable. In spite of variations of the AFP profile in cancer patients, in most cases it was possible to differentiate primary liver cancer from yolk sac tumour and from liver metastases of cancer. In addition, in two-thirds of hepatoma patients the AFP profile was different from the profile observed in patients with benign liver disorders.
 ...
PMID:Microheterogeneity of alpha-fetoprotein in patient serum as demonstrated by lectin affino-electrophoresis. 617 74

Cell growth of tumour ascites cells was inhibited by concanavalin A, phytohaemagglutinin and Ricinus lectin at 2-100 micrograms/ml. As expected, the Ricinus lectin inhibited the protein synthesis estimated by leucine incorporation and decreased thymidine incorporation, whereas concanavalin A and phytohaemagglutinin stimulate the uptake and the incorporation of both leucine and thymidine, and thus, synthesis of protein and DNA. These results suggest that different mechanisms are involved in the hepatoma cell growth inhibition by the lectins. This difference was not related to the kinetic characteristics of the lectin interactions with the cells which represent a first and necessary step. It was showed that concanavalin A and phytohaemagglutinin as well as chloroquine inhibited the 14C-labelled asialofetuin degradation. We can conclude that Ricinus lectin present a toxic effect whereas both concanavalin A and phytohaemagglutinin show an anti-protease activity.
 ...
PMID:Approach to the mechanism of Zajdela's hepatoma cell growth inhibition induced by concanavalin A and phytohaemagglutinin. 618 20

Lectin affinities of AFP were analyzed using Con A sepharose chromatography and crossed immuno-affino-electrophoresis. With Con A, AFP was divided into three subfractions, nonbound, loosely-bound and tightly-bound by chromatography, or two subfractions, nonbound and bound by electrophoresis. Con A nonbound subfraction was small in percentage in hepatocellular carcinoma (HCC), neonatal hepatitis, congenital biliary atresia (CBA), liver cirrhosis (LC) and cord sera. In contrast with these, the increase of Con A non-bound AFP was observed in yolk sac tumor (YST) and metastatic liver cancer (Meta). With LCA, AFP was divided into three subfractions: nonbound, loosely bound and tightly bound. Loosely bound fraction was very small in every specimen. AFPs from cord sera and LC showed uniform LCA affinity pattern, but AFPs from HCC were not uniform. Our data suggest that the analyses of lectin affinity of AFP serve as a diagnostic tool in differentiating (1) HCC from YST, (2) HCC from Meta, (3) CBA or neonatal hepatitis from YST and (4) LC from some cases of HCC.
 ...
PMID:[Analysis of lectin-affinity of alpha fetoprotein-diagnostic approach]. 619 65

Resolution of human alpha-fetoprotein (AFP) into four distinct molecular species was demonstrated by a combination of two affinity chromatographies with crossed-immuno-affino-electrophoresis (CIAE) using concanavalin A (Con A) and Lens culinaris hemagglutinin (LcH)-A and LcH-B as affinity media. Of the four AFPs, AFP1 had no affinity for Con A, LcH-A, or LcH-B; AFP2 showed a high affinity for Con A, a low affinity for LcH-A, and an intermediate affinity for LcH-B (or a low affinity, depending on the lot of LcH-B preparations used); AFP3 revealed strong affinities for all of the three lectins; and AFP4, a trace component of hepatoma AFP in the present study, showed no interaction with Con A, but a definite interaction with LcH-A or LcH-B. These results were based on the determination of dissociation constants (Kd) of AFP-lectin complex by CIAE on isolated preparations of the three major hepatoma AFPs. These AFPs had identical electrophoretic mobilities of 0.86-0.87 (relative to human albumin) in the absence of lectins. The calculated mobilities of AFP2 and AFP3 were both reduced to 0.50-0.58 by saturation with lectins, but these two AFPs were clearly separated by 1 mg/ml LcH-A or LcH-B because of their large differences in Kd.
 ...
PMID:Distinct molecular species of human alpha-fetoprotein due to differential affinities to lectins. 620 49


<< Previous 1 2 3 4 5 6 7 8 9 10