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

By means of immunohistochemical technique ABC, using monoclonal anti-transferrin receptor (TFR) antibodies WuT9 and OKT9, TFR expression in 30 cases of hepatocellular carcinoma (HCC) and in 6 cases of organs and tissues of normal human bodies was studied. It was revealed that large amount of TFR were expressed in liver cancer cells, but not in the surrounding mesenchymal cells as demonstrated by intense immunostaining in cancer nests, and even not in the surrounding mesenchyma of those HCC patients with negative AFP in their serum. In normal human body, only small amount of TFR in limited sites was found without free antigen in blood stream. Thus, it followed that TFR as a structural antigen of HCC was expressed with higher relative specificity than AFP, and TFR may be considered a tumor marker and therapeutic target of HCC.
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PMID:[Immunohistochemical study of transferrin receptor expression in hepatocellular carcinoma]. 132 39

Human transferrin receptor was isolated from placenta and from the hepatocarcinoma cell line Hep G2. Asparagine-linked oligosaccharides were released by treatment of tryptic glycopeptides with endo-beta-N-acetylglucosaminidase H or peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F. Oligosaccharide alditols were fractionated by anion-exchange high-performance liquid chromatography and by high-pH anion-exchange chromatography. Glycans from placental transferrin receptor were further characterized, after desialylation, by methylation analysis and, in part, by liquid secondary-ion mass spectrometry. Sialylation of placental transferrin receptor was examined by lectin affinity blotting with Sambucus nigra agglutinin and Maackia amurensis agglutinin. In order to trace possible inter-individual differences in N-glycosylation of the receptor, two preparations of placental transferrin receptor purified from two donors were compared. The results demonstrate that human transferrin receptor from placenta predominantly carries diantennary and triantennary N-acetyllactosaminic glycans as well as hybrid-type species, the galactose residues of which being almost completely substituted with (alpha 2-3)-linked sialic acid residues. Distinct differences were noted in the glycosylation pattern of the receptor from different individuals. Transferrin receptor from donor A carried predominantly diantennary and triantennary complex-type glycans, in part fucosylated at the innermost N-acetylglucosamine residue, in addition to small amounts of bisected and of incomplete diantennary species. Placental transferrin receptor from donor B predominantly carried triantennary N-acetyllactosaminic glycans without fucose and hybrid-type oligosaccharides with four or five mannose residues. Distinct from placental transferrin receptor, the receptor from Hep G2 cells contained larger amounts of oligomannosidic glycans with six to nine mannose residues and tetrasialylated complex-type oligosaccharides apart from mono-, di- and trisialylated species.
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PMID:Structure of the N-linked oligosaccharides of the human transferrin receptor. 155 86

Interleukin-1 (IL-1 beta) increases the synthesis of both heavy and light (L)-ferritin subunits when added to human hepatoma cells (HepG2) grown in culture. RNase protection and Northern blot analysis with L-ferritin probes revealed that no changes in L-ferritin mRNA levels occur after cytokine stimulation. However, the induction coincides with an increased association of the L-subunit mRNA with polyribosomes. Since the recruitment of stored ferritin mRNA onto polyribosomes is seen when iron enters the cell, the effect of IL-1 beta on iron uptake was tested and was found to be unaffected by the lymphokine. Neither transferrin receptor mRNA levels nor the number of receptors displayed on the cell surface was affected by IL-1 beta. However, the action of the cytokine on ferritin translation is inhibited by the action of the intracellular iron chelator deferoxamine. These data indicate that IL-1 beta induces ferritin gene expression by translational control of its mRNA. The pathway of induction is different from iron-dependent ferritin gene expression whereas regulation requires the background presence of cellular iron.
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PMID:Translational control during the acute phase response. Ferritin synthesis in response to interleukin-1. 169 48

Transferrin receptors take up transferrin-iron complexes into hepatic cells. Although the receptor is not highly expressed in normal liver cells, malignant transformation of the cells increases its expression. As part of the expressed receptors are released into blood, a significant increase of serum receptors are observed in cases of hepatoma. Therefore, measurement of transferrin receptors in blood from patients with hepatoma may be useful for estimating the tumor burden and determinating therapeutic effects. Asialoglycoprotein receptors are expressed strongly in normal liver cells, whereas the expression is decreased in various chronic liver diseases and hepatoma. Although the active shedding of the receptors clearly occurs in vitro, as does that of the transferrin receptor, determination of the significance of these shed receptors in blood will require further studies.
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PMID:Mechanism and clinical significance of soluble hepatic cell-surface receptors. 179 62

One proposed function of the asialoglycoprotein receptor in hepatocytes is to mediate the endocytosis of galactose and N-acetylgalactosamine-exposing glycoproteins. Recently we defined a pool of intracellular H1 subunits of the asialoglycoprotein receptor (ASGPR) in the human hepatoma cell line HepG2 which appeared not to be involved in endocytosis (Stoorvogel, W., Geuze, H. J., Griffith, J. M., Schwartz, A. L., and Strous, G. J. (1989) J. Cell Biol. 108, 2137-2148). In addition, a pool of stably phosphorylated intracellular ASGPR has been detected (Fallon, R. J., and Schwartz, A. L. (1988) J. Biol. Chem. 263, 13159-13166). In the current study we integrate these findings and provide evidence for the existence of two types of intracellular nonexchangeable compartments containing ASGPR. A transiently phosphorylated pool of ASGPR shuttles between the plasma membrane and endosomes, via a pathway identical to that of the transferrin receptor. The second pool comprises 20% of the total intracellular ASGPR, is stably phosphorylated at a serine residue, and is located in intracellular compartments devoid of recycling transferrin receptor. We refer to this ASGPR pool as the "silent pool." We furthermore show that the two receptor pools are confined to compartments exhibiting different buoyant densities on sucrose density gradients. ASGPR in the "silent pool" is fully glycosylated, suggesting a post-Golgi sorting mechanism for trafficking to this compartment. Possible functions of the "silent" ASGPR pool are discussed.
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PMID:A pool of intracellular phosphorylated asialoglycoprotein receptors which is not involved in endocytosis. 200 89

The interactions between transferrin (Tf) and transferrin receptor (Tfr) as they occur during biosynthesis were studied in the human hepatoma cell line HepG2, which synthesizes both. Early during biosynthesis the Tfr monomer is converted to a disulfide-linked Tfr dimer. The Tfr monomer is not able to bind Tf, but Tf binding is observed as soon as the covalent Tfr dimer is formed and can take place in the ER. The Tf-Tfr complex is transported through the Golgi reticulum and trans-Golgi reticulum (TGR) and is ultimately delivered to an acidic compartment, where Tf releases its Fe3+. We did not observe conversion of Tf to apoTf in the TGR, showing that the part of the TGR passed by secreted Tf has a pH higher than 5.5. We conclude that when a ligand-receptor combination is synthesized by one and the same cell, ligand and receptor can interact during biosynthesis and be transported to the cell surface.
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PMID:Intracellular interactions of transferrin and its receptor during biosynthesis. 221 16

Monoclonal antibody PAL-M1, which was selected to discriminate between nevocellular nevi and cutaneous melanomas, has not been characterized until now. Here we show that PAL-M1 is directed against the transferrin receptor (CD71). The molecules precipitated by PAL-M1 and by anti-transferrin receptor antibodies OKT9 and 5E9 from various human tumor cell lines (melanoma, hepatoma, and lymphoma) show identical characteristics on SDS-PAGE. PAL-M1 also specifically recognized mouse L cells expressing the human transferrin receptor gene. Competition experiments demonstrated that PAL-M1 and OKT9 recognize the same or a spatially close determinant. Immunohistochemical staining of a large series of melanocytic lesions indicates that the transferrin receptor can be considered as a progression antigen in this type of lesion.
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PMID:Monoclonal antibody PAL-M1 recognizes the transferrin receptor and is a progression marker in melanocytic lesions. 236 2

Using an indirect immunoperoxidase technique on frozen sections with the monoclonal antibody 96.5, we investigated the in situ distribution of melanotransferrin, a transferrin (Tf) and transferrin receptor (TfR) related glycoprotein, in human liver. Specimens included normal liver, liver in iron overload, hepatocellular carcinoma, angioma and foetal liver. On light microscopy, immunoreactivity was almost exclusively present on sinusoidal lining cells, apparently endothelial cells; the pattern was similar in normal and in iron-loaded liver. A gradient of more enhanced staining in acinar zone II and III was observed. The endothelial localization of the staining was supported by the positivity of the central vein endothelium and of the angiomas. Immunoelectron microscopy on three liver specimens showed positivity on sinusoidal endothelial cells but not on Ito and Kupffer cells. In addition, positivity on rough endoplasmic reticulum vesicles of some hepatocytes was also present. Four hepatocellular carcinomas showed an intense staining in tumour cells, 3 were weakly positive and 3 were negative. In the foetal livers, the central vein endothelium was positive from 21 weeks of gestation onward and additional positivity of zone III sinusoidal endothelial cells was present from 27 weeks on. The present results show that in the liver melanotransferrin has a localization different from Tf and the TfR. These latter molecules are predominantly localized in parenchymal cells. In addition, there does not appear to be a coordinate regulation secondary to iron storage, between melanotransferrin, Tf and the TfR. The observed gradient in the staining pattern in foetal and adult liver specimens further supports the heterogeneity of the endothelial cell population in the liver and suggests a developmental relationship between endothelial cells of sinusoids and central vein.
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PMID:In situ localization of melanotransferrin (melanoma-associated antigen P97) in human liver. A light- and electronmicroscopic immunohistochemical study. 254 Mar 89

Hemopexin (HPX) transports heme to liver parenchymal cells, undergoes receptor-mediated endocytosis, and recycles intact. Incubation of mouse hepatoma (Hepa) cells with heme-HPX causes a rapid dose- and time-dependent increase in the steady-state level of heme oxygenase (HO) mRNA. A maximum induction of 20-25-fold is achieved within 3 h after incubation with 10 microM heme-HPX. This accumulation of HO mRNA results primarily from increased transcription of the HO gene as judged by in vitro nuclear run-on assays. In addition, receptor-mediated transport of heme into Hepa cells significantly decreases the steady-state level of transferrin receptor (TfR) mRNA. While a 25-30-fold decrease in the amount of TfR mRNA is observed within 3 h of incubation of Hepa cells with 10 microM heme-HPX, no significant change in the rate of TfR gene transcription was detected. These regulatory effects of heme-HPX are not restricted to hepatic cells but are also observed in human promyelocytic HL-60 cells. This is the first direct demonstration of receptor-mediated transport of heme by hemopexin regulating gene expression in mammalian cells.
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PMID:Receptor-mediated transport of heme by hemopexin regulates gene expression in mammalian cells. 255 89

Soluble transferrin receptor (sTfR) in serum of cancer patients was measured by a sandwich enzyme-linked immunosorbent assay, and the effect of sTfR for natural killer cytotoxicity was also studied. The statistical values of sTfR levels in sera were found to be 250 +/- 77 U (Mean +/- SD) in healthy individuals, while 288 +/- 162 U in chronic liver disease, 402 +/- 290 U in hepatocellular carcinoma, 429 +/- 261 U in gastric cancer, 347 +/- 207 U in acute leukemia and malignant lymphoma, and 251 +/- 100 U in other cancer. No significant difference in the sTfR levels among the patients was observed, although the difference between the healthy individuals and the patient groups was shown to be statistically significant at p less than 0.01 level. The effect of sTfR isolated from serum of a patient with iron-deficiency anemia by means of Sephadex G-200 column for natural killer activity was carried out. Cytotoxicity of natural killer cell in healthy individuals was inhibited by sTfR as the dose dependent manner, and the inhibitory rate was found to be 23.1 +/- 12.8% (Mean +/- SD) when the concentration of the sTfR was 1,250 U added in the cytotoxicity test. Furthermore, the inhibitory activity of serum in cancer patients was correlated with the sTfR level. These results suggest that sTfR is one of the inhibitory factors for the natural killer cell activity in vivo, and the factor could be facilitated for tumor growth and metastasis. Therefore, the measurement of sTfR in serum may be useful for monitoring immunological competency in cancer patients.
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PMID:[Elevation of soluble transferrin receptor substance in serum of cancer patients with suppressed natural killer activity]. 261 80


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