Coding of two sphingolipid activator proteins (SAP-1 and SAP-2) by same genetic locus.

Several complementary DNAs (cDNAs) coding for sphingolipid activator protein-2 (SAP-2) were isolated from a lambda gt-11 human hepatoma library by means of polyclonal antibodies. The nucleotide sequence of the largest cDNA was colinear with the derived amino acid sequence of SAP-2 and with the nucleotide sequence of the cDNA coding for the 70-kilodalton precursor of SAP-1 (SAP precursor cDNA). The coding sequence for mature SAP-2 was located 3' to that coding for SAP-1 in the SAP precursor cDNA. Both SAP-1 and SAP-2 appeared to be derived by proteolytic processing from a common precursor that is coded by a genetic locus on human chromosome 10. Two other domains similar to SAP-1 and SAP-2 were also identified in SAP precursor protein. Each of the four domains was approximately 80 amino acid residues long, had nearly identical placement of cysteine residues, potential glycosylation sites, and proline residues. Each domain also contained internal amino acid sequences capable of forming amphipathic helices separated by helix breakers to give a cylindrical hydrophobic domain that is probably stabilized by disulfide bridges. Protein immunoblotting experiments indicated that SAP precursor protein (70 kilodaltons) as well as immunoreactive SAP-like proteins of intermediate sizes (65, 50, and 31 kilodaltons) are present in most human tissues.

Antileukotactic properties of tumor cells.

A chemotactic factor inactivator (CFI) has been found in extracts of Walker and Novikoff tumor cells maintained in rats. The CFI directly inactivates the bacterial chemotactic factor as well as the leukotactic activity (fro both neutrophils and monocytes) associated with C3 and C5 fragments and with culture fluids of lectin-stimulated lymphoid cells. The inactivation of the bacterial chemotactic factor is temperature and pH dependent. Subcellular fractionation procedures indicate that CFI is largely associated with the microsomal and cytosol fractions of tumor cells. CFI activity is also found in rat neutrophils, alveolar macrophages, and in extracts of liver, spleen, and kidney from normal animals. CFI derived from normal tissues also directly inactivates the bacterial chemotactic factor and has the ability to inactivate chemotactic activity associated with C3 and C5 fragments. A feature of the tumor-associated CFI is its presence in ascitic fluids of animals bearing tumor cells and the relative absence of any CFI activity in acute inflammatory exudates. The finding of the tumor-associated CFI may explain, at least in part, the tendency of malignant tumor cells to suppress cellular inflammatory reactions.

Bile acid synthesis by long-term cultured cell line established from human hepatoblastoma.

Bile acids in the spent medium for the cell culture were analyzed by gas-liquid chromatography and gas-liquid chromatography-mass spectrometry to determine whether human hepatoblastoma cell line could synthesize bile acids. Cholic, chenodeoxycholic, and lithocolic acids were found in the culture medium, and a portion of chenodeoxycholic acid and all of lithocholic acid were sulfated. Since the cells had been cultured in serum-free medium, it is clear that the bile acids were newly synthesized and sulfated by the cultured cells. Chenodeoxycholic acid was the main bile acid in the medium, suggesting that the cell line might predominantly synthesize chenodeoxycholic acid. On the other hand, the cells had fetal or hepatoma characters such as marked alpha-fetoprotein production. These results suggest that fetal or hepatoma type bile acid metabolism might occur in the cell line, and that the established cell line could be an useful in vitro model for the study of bile acid metabolism in hepatoma.

Isolation and characterization of a novel vitamin B12-binding protein associated with hepatocellular carcinoma.

High levels of a novel vitamin B12-binding protein (hepatoma B12 BP) have been observed recently in plasma obtained from three adolescent patients with hepatocellular carcinoma. This protein has now been isolated in homogeneous form from the plasma and pleural fluid of two of these patients by the use of affinity chromatography with vitamin B12-Sepharose. The hepatoma B12 BP belongs to the R-type group of B12-binding proteins and is essentially indistinguishable from the recently isolated human milk and saliva R-type proteins in terms of: (a) immunologic properties based on immunodiffusion and immunoprecipitation assays; (b) amino acid composition; (c) molecular weight based on amino acid and carbohydrate content; and (d) absorption spectra. Both hepatoma B12 BPs contain more sialic acid and less fucose than the milk and saliva B12 BPs. All four proteins contain similar amounts of galactose, mannose, galactosamine, and glucosamine. Differences in sialic acid content appear to account for the differences in electrophoretic mobility that were observed among the four proteins. Differences in total carbohydrate content appear to account for the differences in apparent molecular weight that were observed with both gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Tumor tissue from one of the patients contained 10 times as much R-type protein as did normal liver tissue from the same patient. This suggests, although it does not prove, that synthesis by the tumor is the cause of the high levels of R-type protein found in the plasma of certain patients with hepatocellular carcinoma. Plasma survival studies performed with rabbits indicate that the hepatoma B12 BP has a prolonged plasma survival and suggests that his parameter is also of importance.

Detection of membrane-bound alpha-fetoprotein in human hepatoma cell lines by monoclonal antibody 19F12.

Monoclonal antibodies against human alpha-fetoprotein (AFP) were obtained by the hybridoma technique and studied with regard to their reactivities with the human hepatoma cell lines PLC/PRF/5 and KN, and a spontaneously immortalized cell line derived from fetal liver, NuE, all of which synthesize AFP. One of the monoclonal antibodies, 19F12 (IgG2b) became bound to free AFP which was used as the immunogen with an affinity constant of 3.4 X 10(8) M-1. This value was not much higher than those of two other antibodies, 19B1 (IgG1) and 9D12 (IgG2b). However, only antibody 19F12 showed definite reactivity with AFP-producing cells in analysis using flow cytometry. Immunofluorescence microscopy showed that antibody 19F12 detected AFP over the surface of NuE and PLC/PRF/5 cells with a uniform distribution, whereas definite reactivities of antibodies 19B1 and 9D12 to these cells were not detected. These antibodies did not show the specific binding to a non-AFP-producing human lung cancer cell line, PC-9, or to human peripheral blood lymphocytes. The binding ability of 19F12 to hepatoma cells was shown in both viable and fixed cells. Addition of free AFP inhibited the binding of antibody 19F12 to PLC/PRF/5 cells in a concentration-dependent manner. The specific reactivity of 19F12 to human AFP was also confirmed by immunostaining of a tissue section of human cancer proved to be AFP positive with AFP-specific antisera. In two-dimensional polyacrylamide gel electrophoresis of the antigen (from membrane fraction of PLC/PRF/5 cells)-antibody (19F12) complex, spots derived from the antibody and a spot (pI 4.7, Mr 65,000) corresponding in pI and molecular weight to AFP were detected. Western blot analysis showed that material in the membrane fraction of PLC/PRF/5 cells recognized by antibody 19F12 has the same molecular weight as human AFP derived from placenta. In a study of reactivities to PLC/PRF/5 cells treated with various enzymes, the reactivity of this antibody decreased when cells were treated with protease and trypsin and increased when lipase was used. The binding of 19F12 to AFP was not inhibited by concanavalin A. The antibody 19F12 appeared to recognize an epitope that is considered to be part of the peptide area of AFP. These results indicate that the reactivity, the amount of bound antibodies, and the distribution of monoclonal antibodies on antigen-producing cells vary, respectively, even though these antibodies were produced using the same antigen as an immunogen.(ABSTRACT TRUNCATED AT 400 WORDS)

Physicochemical approach to the purification of human alpha1-fetoprotein from the ascites fluid of a hepatoma-bearing patient.

A method for the purification of human alpha1-fetoprotein from the ascites fluid of a hepatoma-bearing patient is described that is capable of yielding large quantities of pure alpha1-fetoprotein within a relatively short period of time. The technique is based entirely on the physicochemical properties of the alpha1-fetoprotein molecule and uses sequential purification steps: ion-exchange chromatography on DEAE-Sephadex A-50, molecular-sieve chromatography on Sephadex G-200, negative-affinity chromatography on Sepharose-Blue Dextran, positivepaffinity chromatography on concanavalin A-Sepharose and, finally, molecular-sieve chromatography on Sephadex G-100. The efficiency of the entire procedure in its present form is 15% of the alpha1-fetoprotein activity of the starting preparation from ascites fluid. The purity of the final product was shown by polyacrylamide gel electrophoresis, radioimmunoelectrophoresis, and determinations of the NH2-terminal and COOH-terminal amino acid residues of the alphs1-fetoprotein isolated. Amino acid analysis of the final product revealed a composition very similar to those reported for alpha-fetoprotein preparations that have been previously isolated by the use of immunochemical technology.

Phase transition of plasma membranes of rat hepatocyte and hepatoma cells by electron diffraction.

The transition temperatures (Tc) of the plasma membranes of Reuber H-35 hepatoma and normal ACl rat hepatocytes were measured by electron diffraction under physiological conditions. Diffraction rings below Tc indicate the existence of solid lipid domains. The Tc of both membranes increase to a plateau value of 17.5 degrees during the storage period of 4 days at 4 degrees, the rate of increase being slower for normal liver membranes. The extrapolations to zero storage suggest an innate difference of Tc for these two membranes. Storage in oxygen-reduced media slows down the initial increase in Tc in normal liver membranes, while the depletion of divalent cations accelerates the increase. Differences in lipid composition are partly responsible for this behavior.

Isolation and characterization of a hepatoma-associated abnormal (des-gamma-carboxy)prothrombin.

Hepatoma-associated abnormal (des-gamma-carboxy)prothrombin (HAPT) is a newly described tumor marker for hepatocellular carcinoma. HAPT has been measured in the blood of patients with hepatoma by immunoassay but has not been isolated or characterized. This paper describes the quantitative isolation and structural characterization of HAPT. Purified HAPT has the same molecular weight, amino-terminal sequence, and amino acid analysis (exclusive of gamma-carboxyglutamic acid) as native prothrombin and abnormal prothrombin isolated from the blood of patients taking sodium warfarin. HAPT is heterogeneous in gamma-carboxyglutamic acid (Gla) content with an average of 5 Gla residues/molecule compared to 10 Gla residues for native prothrombin and 2 Gla residues for abnormal prothrombin. HAPT is glycosylated in a manner equivalent to that for native prothrombin when evaluated by a concanavalin A-binding assay. These studies find structural identity between HAPT and abnormal prothrombin. Therefore the findings support the hypothesis that HAPT results from an acquired defect in the posttranslational vitamin K-dependent carboxylation of the prothrombin precursor and not an intrinsic defect in the prothrombin precursor molecule.

Chromatin-associated glycoproteins of normal rat liver and Novikoff hepatoma ascites cells.

Glycoproteins were demonstrated in the 0.6 M NaCl extract of chromatin of normal liver and Novikoff hepatoma cells by periodic acid-Schiff staining of sodium dodecyl sulfate-polyacrylamide gels. In chromatin extracts of Novikoff hepatoma cells, six major periodic acid-Schiff-positive bands coincident with Coomassie Blue-stained protein bands were found with molecular weights of 30,000, 54,000, 64,000, 75,000, 104,000, and 127,000. A corresponding extract from normal rat liver chromatin revealed the presence of four major periodic acid-Schiff-positive bands that migrated with protein bands at molecular weights of 16,000, 30,000, 54,000, and 75,000. The glycoproteins of these extracts contained either mannose or alpha-D-glucose, fucose, and N-acetylglucosamine as shown by the specificity of lectins in affinoelectrophoresis. One of the glycoproteins detected by affinoelectrophoresis was very basic.

Some biochemical characteristics of rat liver and Morris hepatoma nuclei and nuclear membranes.

Nuclei prepared from host liver and from Morris hepatomas 7777 and 7800 have been compared with respect to some of their biochemical characteristics. Several criteria were used to ensure that liver and hepatoma nuclei were of equal purity. These criteria include equal specific activity ratios (homogenate nuclei) for several marker enzymes. Phospholipids, proteins, and sialic acid content were compared in liver and hepatoma sucrose nuclei and in membrane and chromatin fractions obtained from liver or hepatoma nuclei. As determined by sodium dodecyl sulfate polyacrylamide electrophoresis, the only qualitative difference in protein that could detected was in 2 of the 4 nuclear fractions. There was an extra band in each of the 2 hepatoma fractions. Sialic acid was increased in hepatoma nuclei. In addition, a fraction containing most of the inner nuclear membrane from liver nuclei had no sialic acid, whereas the equivalent hepatoma fraction did have sialic acid. Total phospholipids were increased in hepatoma nuclei. This increased phospholipid concentration in hepatoma nuclei as compared to liver nuclei was apparent with sucrose nuclei, citric acid nuclei, membrane-denuded nuclei, chromatin, and nuclear fractions. Determination of the percentages of individual phospholipids making up the total phospholipids extracted revealed that the only significant change in the phospholipid composition of hepatoma nuclei was an increase in sphingomyelin. A large amount of this sphingomyelin was found to be associated with chromatin. The possible significance of chromatin-associated phospholipids is discussed.

Detection of messenger RNAs of alpha-fetoprotein and albumin in a human hepatoma cell line by in situ hybridization.

Detection of RNA transcripts within individual cells by in situ hybridization provides a powerful means for identifying specific cell types actively transcribing specific genes. We have applied this technique in order to analyze expression of the alpha-fetoprotein and albumin genes in a human hepatoma cell line, HuH-7. Using either 3H- or 35S-labeled human alpha-fetoprotein complementary DNA clone as a probe, we found that essentially all HuH-7 cells contained alpha-fetoprotein mRNA, although in various amounts. This correlated well with the presence of alpha-fetoprotein in all cells as detected by the peroxidase-antiperoxidase immunoenzyme method. The intracellular concentration of albumin, on the other hand, was below the level of detection by the peroxidase-antiperoxidase method. Consistent with this observation, we could not detect albumin mRNA with 3H-labeled albumin complementary DNA probes. However, the use of 35S-labeled probes having higher specific activities and higher efficiency of grain development resulted in the detection of albumin mRNA in a small percentage of HuH-7 cells. A variety of parameters involved in the in situ hybridization technique was examined to establish conditions suitable for demonstrating the presence of high- and low-copy numbers of mRNA in various cell and tissue preparations.

Comparative chemical structures of human alpha-fetoproteins from fetal serum and from ascites fluid of a patient with hepatoma.

Human alpha-fetoproteins were purified from umbilical cord serum and from ascites fluid of a patient with hepatoma by affinity chromatography, and their chemical compositions and terminal sequences were compared. The amino acid compositions of these alpha-fetoproteins were similar and in good agreement with the values reported by other investigators. The COOH-terminal 5-amino acid sequence determined by carboxypeptidase digestion and the NH2-terminal 20-amino acid sequence determined by an automated sequence analyzer revealed that both alpha-fetoproteins had the same terminal sequences of amino acids. The sequence analysis showed that a part of each of the proteins lacked its NH2-terminal residues for one or three amino acids. A small difference in the carbohydrate composition of each alpha-fetoprotein was observed. It was concluded that alpha-fetoproteins from fetal serum and from ascites fluid of a patient with hepatoma had very similar structures.

Accumulation of gangliosides with N-acetylneuraminosyl(alpha 2-6)lactosamine structure in primary human hepatoma.

Gangliosides of hepatomas have been analyzed by using a monoclonal antibody directed to N-acetylneuraminosyl(alpha 2-6)lactoneotetraosylceramide (sialyl(alpha 2-6)paragloboside), which was prepared by injecting the monosialoganglioside fraction of human meconium into BALB/c mice. The monoclonal antibody, named MSG-15, was found to bind sialyl(alpha 2-6)paragloboside, but it failed to react with other gangliosides, including N-acetylneuraminosyl(alpha 2-3)lactoneotetraosylceramide (sialyl (alpha 2-3)paragloboside) and "Ii"-type gangliosides. MSG-15 was found to recognize NeuAc alpha 2-6Gal beta structure of the ganglioside. Gangliosides obtained from human hepatomas were analyzed by immunostaining on high-performance thin-layer chromatography plates using the monoclonal antibody MSG-15. All primary hepatoma samples used in this study (nine samples) were found to contain sialyl(alpha 2-6)paragloboside, which accounted for 13-31% of the monosialoganglioside fractions in the hepatomas. Furthermore, MSG-15 recognized several monosialogangliosides in addition to sialyl(alpha 2-6)paragloboside. These gangliosides apparently also contain a terminal NeuAc alpha 2-6Gal beta structure. Other ganglioside fractions obtained from hepatoma and meconium were immunostained on thin layer chromatography plates with MSG-15. Additionally, another monoclonal antibody (H-11), which recognizes terminal lactosamine structure, was used to immunostain these fractions after sialidase treatment. Bands stained with both monoclonal antibodies showed similar mobilities to each other in the di- and trisialoganglioside fractions as well as monosialoganglioside fraction. In control liver, GM3 ganglioside accounted for 92% of monosialoganglioside fraction, and sialyl(alpha 2-6)paragloboside accounted for less than 1% of the fraction. Immunohistochemical study by using MSG-15 in tissue sections from hepatocellular carcinoma and normal liver tissues demonstrated that only hepatocellular carcinoma cells gave a positive reaction. These results suggest that the biosynthetic pathway of gangliosides containing NeuAc alpha 2-6Gal beta 1-4GlcNAc beta structure is activated in hepatoma cells.

Expression of human alpha-actinin in human hepatocellular carcinoma.

Little is known regarding gene expression during hepatocyte transformation. We have isolated an alpha-actinin complementary DNA from a human hepatocellular carcinoma library. This partial 2.4-kilobase complementary DNA has high homology with human placental and chicken nonmuscle alpha-actinins; our isolate contains the entire 3' noncoding region and it is within these sequences where the major differences between the vertebrate alpha-actinin complementary DNAs arise. Northern analysis revealed a 3.5-kilobase transcript in nonmuscle and a smaller 3.0-kilobase species in muscle tissue. Levels of alpha-actinin expression were low in normal liver and we investigated its expression during both hepatocyte proliferation and transformation. We found no increase during rat hepatocyte regeneration up to 24 h following two-thirds hepatectomy. However, high levels of alpha-actinin transcripts were observed in human hepatocellular carcinoma compared to noninvolved adjacent liver. We conclude that the alpha-actinin gene is highly expressed when hepatocytes have assumed the malignant phenotype.

Cytidine 5'-triphosphate-dependent dolichol kinase and dolichol phosphatase activities and levels of dolichyl phosphate in microsomal fractions from highly differentiated human hepatomas.

Homogenates and microsomal fractions prepared from biopsies of highly differentiated human hepatocellular carcinomas were found to contain low levels of dolichol in comparison with control tissue. In contrast, the amount of dolichyl phosphate in tumor homogenates was unchanged and actually increased in the microsomal fraction. The pattern of individual polyisoprenoids, both in the free and the phosphorylated dolichol fractions of hepatomas, did not exhibit any major alterations compared to the control. The rates of incorporation of [3H]mevalonic acid into dolichol and dolichyl phosphate in hepatomas were low. The dolichol monophosphatase activities in microsomal fractions from hepatomas and controls did not show any major differences, whereas the activity of the CTP-dependent dolichol kinase was increased in tumor microsomes. Glycosylation of endogenous dolichyl phosphate and of total protein using certain nucleotide-activated sugars was found to be slightly elevated in microsomal fractions from the tumor itself when compared to the control. The reasons for the differences in the levels of polyisoprenoids in hepatomas and control tissue are discussed.

Carbamyl phosphate synthetases in rat liver neoplasms.

Isozymes of carbamyl phosphate synthetase (CPS), CPS I, a mitochondrial enzyme found exclusively in liver and involved in urea synthesis, and of CPS II, a soluble cytoplasmic enzyme widely distributed in animal tissues, were assayed in rat liver and in a series of rat liver neoplasms ranging widely in growth rate and degree of differentiation. CPS I was absent from fast-growing, poorly differentiated hepatomas, such as the Novikoff hepatoma and Morris hepatomas 3924A and 9098F, but was present in slow-growing, well- and highly differentiated Morris hepatomas. However, there was no close correlation between the growth rate or degree of differentiation and the CPS I activity. Activity was very high, at levels comparable with normal liver at about 9 UNITS/G, IN SLOW-GROWING, HEPATOMAS 21, 47C, and 28A but was very low in other slow-growing highly differentiated hepatomas 9618A, 66, and 16. CPS II activity was present in normal liver and all hepatomas examined, but with very low activity, of the order of 1% or less of that of CPS I activity, with maximal values at 5 to 70 milliunits/g. Again, there was no clear correlation with growth rate; the activity was lowest in fast-growing, poorly differentiated hepatomas. A striking observation was a marked lowering of CPS I activity in livers of rats bearing large, slow-growing tumors that have high CPS I activity. As the tumors grew larger and the liver CPS I decreased, a relatively constant total CPS I activity was maintained, suggesting the existence of a homeostatic mechanism. The effect was not observed in rats bearing either fast-growing hepatomas or slow-growing hepatomas with low CPS I activity and was not due to some specific nutritional effects of the tumor on the host.

A quantitative study of the subcellular localization of 67Ga.

This paper describes a quantitative procedure for the isolation of 67 Ga-binding granules (GBG) from normal rat liver and Morris 5123C hepatoma homogenates by a combination of rate and isopyknic density gradient zonal centrifugation. Another class of GBG has been found that is much smaller than the lysosomal GBG we have previously described. These smaller particles, or microvesicles, bind the largest portion of the 67Ga found in the hepatoma whereas, in the liver, the GBG lysosomes are the major binding component. Previously, we had shown that considerably more 67Ga is taken up in hepatoma than in liver (as percentage of administered dose per g of tissue). The preferential association of 67Ga with these microvesicles in the 5123C hepatoma may be indicative of a basic difference between normal and malignant tissue.

Alterations in the expression of a hepatocyte cell adhesion molecule by transplantable rat hepatocellular carcinomas.

Alterations in the expression of normal cell surface components on 13 transplantable hepatocellular carcinomas were examined using a heteroantiserum [anti-Mr 105,000 glycoprotein (gp 105)] reactive with a family of nine wheat germ agglutinin binding components from normal rat hepatocytes with an average molecular weight of 105,000. Analysis by two-dimensional polyacrylamide gel electrophoresis of components immunoprecipitated by anti-gp105 antiserum from detergent extracts of transplantable hepatocellular carcinoma cells surface labeled with 125I revealed qualitative and quantitative changes in the expression of anti-gp105-reactive components with the most consistent change being the apparent loss of a pair of acidic (pl 4.1 to 4.3) glycoproteins by all 13 transplantable hepatocellular carcinoma lines. One-dimensional peptide maps of fragments produced following digestion with V8 protease indicated that these acidic components were closely related in structure but differed significantly from other anti-gp105-reactive components. Immunodepletion analysis with monoclonal antibodies and heteroantisera reactive with individual components recognized by anti-gp105 antiserum showed that the two acidic glycoproteins were antigenically and structurally identical to cell-CAM 105, a Mr 105,000 glycoprotein involved in cell-cell adhesion of rat hepatocytes. Antibodies raised against purified cell-CAM 105 were specific in immunoprecipitation assays for the acidic components, strongly inhibited reaggregation of hepatocytes, and displayed no reactivity by indirect immunofluorescence or immunoprecipitation analysis with transplantable hepatocellular carcinoma cells. These results suggest that major alterations in the expression of cell-CAM 105 may be a consistent feature of the malignant phenotype.

Antigenically active nonhistone chromatin proteins in cancer cells.

Two-dimensional polyacrylamide gel electrophoresis shows that in nuclei of Novikoff hepatoma ascites cells there are approximately 75 proteins in the chromatin fraction soluble in 3 M NaCl:7 M urea. Dialysis of this fraction to an ionic strength of 0.15 produces a soluble fraction and a precipitate. The proteins in the soluble fraction have been reported to be active in gene control. Antibodies to the soluble fraction distribute diffusely throughout the nucleus, and antibodies to the precipitate localized primarily in the nucleolus and the nuclear ribonucleoprotein network. The nucleolar proteins differ from the extranucleolar proteins in antigenicity and labeling patterns. The development of methods for isolation, purification, and identification of nuclear proteins provided the opportunity for analysis of chromatin antigens in tumor cells. Utilizing two-dimensional preparative polyacrylamide gel techniques as well as conventional procedures, several nuclear proteins have been isolated in electrophoretically homogeneous states including protein A-24, a histone-like nonhistone protein; C-14, a protein that stimulates nucleolar RNA polymerase; and a chromatin antigen soluble in 3 M NaCl:7 M urea that remains soluble after dialysis to 0.15 M NaCl to precipitate the histones and the DNA. This antigen has been found in the chromatin of both the Novikoff hepatoma and the Walker 256 carcinosarcoma but not in the chromatin of either normal or regenerating liver. It is a nonhistone nuclear protein as indicated by its amino acid analysis in which the ratio of the number of acidic to basic amino acids is approximately 1.4. Further studies are in progress on the function and structure of this chromatin protein. As an approach to analysis of relative rates of synthesis of this antigen and otherproteins, the products of translation of messenger RNA of Novikoff hepatoma and normal liver are being analyzed by autoradiography of two-dimensional electrophoretic gels.

The glycosaminoglycans in human hepatic cancer.

A method is proposed for the analysis of glycosaminoglycans that were isolated from human liver, combining cellulose acetate electrophoresis and enzymatic digestion with mucopolysaccharidases. The major constituent of glycossaminoglycans in the healthy liver is heparin sulfate and/or heparin (about 65%), with approximately equal quantities of dermatan sulfate and hyalauronic acid (about 13.5 and 13%, respectively) and a small amount of chondroitin sulfate. These components, especially chondroitin sulfate and hyaluronic acid, are markedly increased in hepatic carcinomas.