Beta-Elimination and sulfite addition reaction of chondroitin sulfate peptidoglycan and the peptide structure of the linkage region.

Pronase digestion of bovine tracheal cartilage yielded acid mucopolysaccharide - peptide complexes which were fractionated by chromatography on Dowex 1(C1-). A major fraction was eluted with 1.5 M NaC1 and presumed to by chondroitin sulfate A-peptidoglycan by cellulose acetate electrophoresis. Alkaline beta-elimination and sulfite addition reaction of this fraction yielded cysteic acid-containing peptides, two of which were obtained in an homogeneous state. The sequence determination of these two made it possible to remodel their original structures as Leu-Pro-Ser-Gly-Glu-Gly-Pro-Glu and Leu-Pro-Ser-Gly-Glu, where the serine residues carried polysaccharide chains. Together with the reported data on the polysaccharide-protein linkage region, the present result suggests that the -Ser-Gly- sequence is a minimum requisite for the glycosylation of serine residues in the protein core of various proteoglycans.

Cell adhesion activity for murine carcinoma cells of a wheat germ 55-kDa protein with binding affinity for animal extracellular matrix proteins.

A wheat germ 55-kDa protein was isolated by affinity chromatography with Matrigel immobilized on agarose, followed by preparative gel electrophoresis. This Matrigel-binding protein designated as WG-55 had an amino-terminal amino acid sequence which is identical to that of a putative mature form of wheat storage protein Gbl 1. WG-55 reacted with concanavalin A, indicating its glycoprotein nature as expected from the amino acid sequence of Gbl 1. As expected, similarly, WG-55 exhibited RGD-dependent cell adhesion activity for murine carcinoma cells. These data suggest that WG-55 or mature Gbl 1 protein may play a role in plant cell adhesion.

Fucosylation of serum alpha-fetoprotein in patients with primary hepatocellular carcinoma.

alpha-Fetoprotein specimens were prepared from the sera of four patients with hepatocellular carcinoma. The lentil lectin-reactive and lectin-nonreactive variants of this glycoprotein were also prepared from the serum of one of the four patients by affinity chromatography with immobilized lectin. The correlation between the carbohydrate structure of these compounds and their reactivity in crossed immuno-affinoelectrophoresis with lentil lectin was studied by chemical analysis and affinity chromatography of the glycopeptides with lectin columns. It was found that the lentil lectin-reactive variant contained a carbohydrate chain of the fucosylated biantennary complex type. These data together with previous findings indicate that most of the patients with hepatocellular carcinoma have an elevated serum concentration of fucosylated alpha-fetoprotein.

Further characterization of porcine plasma fibronectin which contains fucosylated carbohydrate chains.

Porcine plasma fibronectin and its functional four fragments produced by cathepsin B digestion were examined for biological, immunochemical and biochemical properties. Native fibronectin, 150-kDa and 130-kDa fragments exhibited similar cell attachment-promoting activity to each other. In an Ouchterlony double immunodiffusion system, these three polypeptides formed a precipitin line with anti-fibronectin antiserum, while the 50-kDa and 30-kDa fragments did not. The 150-kDa and 130-kDa fragments contained free sulfhydryl(s). The glycopeptide fractions were prepared by pronase digestion of porcine and human plasma fibronectin, and radiolabeled with [14C]acetic anhydride. The results of affinity chromatography with concanavalin A and lentil lectin immobilized on agarose indicated that the porcine glycopeptide fraction was different from the human fraction in that a larger part (58%) of the former was bound to lentil lectin. About 90% of this lentil lectin-reactive glycopeptides lost this reactivity upon alpha-L-fucosidase digestion. The glycopeptide fractions were also prepared from three carbohydrate-containing domains. Less than 30% of the radioactivity of the glycopeptide fractions of 150-kDa and 130-kDa fragments was retained on the lentil lectin-agarose, while about 90% of that from the 50-kDa fragment was retained. These results indicate that porcine plasma fibronectin has characteristics very similar to those of human plasma fibronectin and others, but is unique in that it contains fucosylated carbohydrate chains which unevenly distribute through functional domains.

Characterization of fibronectin from fetal human plasma in comparison with adult plasma fibronectin.

Fibronectin was purified from fetal human plasma and characterized in comparison with fibronectin from adult human plasma. Fetal plasma fibronectin had an amino-acid composition, immunological properties, and cell-attachment-promoting activity similar to those of adult plasma fibronectin. However, fetal plasma fibronectin was shown to have a distinct carbohydrate composition which is characterized by the presence of fucose. To ascertain the differences in the carbohydrate moiety, 14C-labeled glycopeptides were prepared and sequentially analyzed with columns of immobilized concanavalin A and lentil lectin. Glycopeptides from fetal plasma fibronectin contained a population of glycopeptides which bound to both lectin gels. Almost all of the glycopeptides in this population lost their ability to bind to lentil lectin upon fucosidase digestion, indicating that fetal plasma fibronectin possesses a substantial amount of fucosylated biantennary glycans. In contrast, glycopeptides from adult plasma fibronectin practically lacked such glycopeptides. Another difference observed was that fetal plasma fibronectin had a larger amount of concanavalin A-unbound glycopeptides than did adult plasma fibronectin. These results indicate the presence of age-related variation in glycosylation of human plasma fibronectin.

Isolation and characterization of chondroitin sulfate proteoglycans from porcine thoracic aorta.

A chondroitin sulfate proteoglycan fraction was prepared from the 3 M MgCl2 extract of porcine aortas by DEAE-cellulose chromatography, followed by gel filtration through Sepharose CL-4B. Affinity chromatography of the fraction with antithrombin III-agarose yielded two chondroitin sulfate proteoglycans of a non-binding (proteoglycan IA) and binding (proteoglycan IB) nature. Proteoglycans IA and IB were different from each other in molecular size, in proportion of the protein relative to the polysaccharide portion, and in size of the chondroitin sulfate chain. They were also distinguished immunochemically. These data indicate that the intima-media of the aorta contains at least two distinct species of chondroitin sulfate proteoglycan.

Isolation of dermatan sulfate with high heparin cofactor II-mediated thrombin-inhibitory activity from porcine spleen.

We prepared dermatan sulfate specimens from various porcine tissues, and compared their heparin cofactor II-mediated thrombin-inhibitory activities and chemical natures, including disaccharide composition. Electrophoresis of the specimens on cellulose acetate membrane indicated that spleen dermatan sulfate was the most acidic of the dermatan sulfates prepared from the various porcine tissues. Analysis of the disaccharide units of the dermatan sulfate specimens by high-performance liquid chromatography revealed that spleen dermatan sulfate was rich in 4,6-di-O-sulfated N-acetylgalactosamine residues as compared with those of the other tissues. Spleen dermatan sulfate exhibited the highest thrombin-inhibitory activity, which may be related to its high content of the disulfated N-acetylgalactosamine residue.

Effects of extracellular matrices on human keratinocyte adhesion and growth and on its secretion and deposition of fibronectin in culture.

Extracellular matrices (ECMs) play an important role as components of basement membrane of normal human skin and in migrating epidermal cells in wound healing. We investigated the effects of various ECMs on human keratinocyte adhesion and growth as well as on its secretion and deposition of fibronectin (FN) in vitro using a serum-free, low-calcium culture system. Since cell adhesion is the first step of cell growth, we performed cell adhesion assay for 14 h. Human keratinocytes adhered best on FN and less well on types I/III collagen, type IV collagen, and heparan sulfate proteoglycan (HSPG) as compared with bovine serum albumin (BSA) (control) or laminin (La). Cell growth assayed for 7-8 days on the dishes coated with various extracellular matrices revealed significantly increased keratinocyte growth on FN and on types I/III collagen in comparison with that on type IV collagen, HSPG, BSA (control), or La. Morphology of keratinocytes and of their colonies on FN and types I/III collagen was strikingly different from that of the control; the colonies were not so compact as in the control, but rather loose and larger; each keratinocyte was spread out more on these substrata. These morphologic features seemed to correlate with the increased keratinocyte growth on these extracellular matrices. Both immunofluorescence study for FN with keratinocytes in 8-day culture on various extracellular matrices and enzyme-linked immunosorbent assay for FN measurement on substratum or in conditioned medium with keratinocytes in 5-day culture demonstrated that extracellular matrices modulated the secretion and deposition of FN by human keratinocytes in culture; the keratinocyte growth correlated with the amount of FN detected on substratum but not with that in medium. Based on the results of the present investigation, we think that the growth of human keratinocytes depends on the amount of FN on substratum.

Immunohistochemical alterations in basement membrane components of squamous cell carcinoma.

To investigate alterations in the basement membrane (BM) in squamous cell carcinoma (SCC), we investigated 20 tumors. Four had the cytologic characteristics of Bowen's disease (SCC-BD) and 16 did not have them (SCC-NB). Tumors were studied immunohistochemically by double immunofluorescent staining by using mouse monoclonal antibodies to the core protein of heparan sulfate proteoglycan (HSPG) and chondroitin 6-sulfate glycosaminoglycan (Ch6S) as well as rabbit antiserum to laminin (LN) and type IV collagen (C-4). In well-differentiated and highly keratinized SCC-NB, LN, C-4, and HSPG could be detected in the tumor nest BM and showed no loss of continuity, but they were largely lost in poorly differentiated and poorly keratinized SCC-NB. This suggests that poorly differentiated SCC-NB cause greater enzymatic degradation of BM components than well-differentiated SCC-NB. Ch6S was detected in parts of the BM of SCC-BD, but it was absent in all SCC-NB examined. It appears that SCC-NB have lost the ability to synthesize Ch6S, and that SCC-BD degrade Ch6S although they continue to produce it. Thus, it appears that in SCC the BM is qualitatively different from that of normal epidermis, and that SCC-BD can be distinguished from SCC-NB by the Ch6S content of the BM.

Inhibitory effect of epigallocatechin gallate on adhesion of murine melanoma cells to laminin.

We examined the effects of five kinds of green tea catechin on the adhesion of mouse melanoma B16 cells to laminin. (-)-Epigallocatechin gallate (EGCG) and (-)-epicatechin gallate in the culture medium were found to inhibit the cell adhesion. The adhesion to laminin pre-treated with EGCG was also impaired. Affinity chromatography revealed the binding affinity between laminin and EGCG. These data suggest that the inhibitory effect of EGCG on adhesion of melanoma cells to laminin is included in the mechanism(s) of previously reported metastasis inhibition elicited by EGCG and green tea infusion.

Inhibitory effects of green tea infusion on in vitro invasion and in vivo metastasis of mouse lung carcinoma cells.

The peroral administration of green tea infusion reduced the number of lung colonies of mouse Lewis lung carcinoma cells in a spontaneous metastasis system. The experiments with artificially reconstituted basement membrane suggested that this reduction could be understood by the inhibitory effects of the green tea infusion and its constituent catechins on the penetration of the cells through the basement membrane.

Expression of the 37-kDa laminin binding protein in murine lung tumor cell correlates with tumor angiogenesis.

Expression of the 37-kDa laminin binding protein (37LBP), a precursor protein of the 67-kDa laminin receptor, correlates well with the biological aggressiveness of cancer cells. Previously, we have established murine lung cancer cell lines T11 and T15, in which 37LBP expression was remarkably diminished, and reported that the mean survival time of the T11 and the T15-recipients was significantly prolonged compared with that of the control cell lines (P29 and T42). In the present study, immunohistochemical findings of the tumors demonstrated that the microvessel density in the T11 (28. 1+/-7.2/mm(2)) and in the T15 tumor (29.7+/-6.5/mm(2)) were significantly lower than that observed in P29 (46.3+/-8.7/mm(2)) or in T42 (50.5+/-4.4/mm(2)). Expression of vascular endothelial growth factor (VEGF) was repressed in T11 and T15 compared with its expression in P29 and T42. It was also shown that conditioned media of T11 and T15 cells exhibited significantly reduced proliferation and migration of the capillary endothelial cells. These results suggest that decreased expression of 37LBP in antisense-RNA transfectant may relate to its low tumorigenicity, and that this effect may be partly caused by the diminished tumor angiogenesis of murine lung cancer.

Immunohistochemical detection of the laminin receptor polypeptide, a putative precursor of 67-kda-laminin receptor, in human lung-cancer.

Laminin receptor polypeptide was immunodetected in human lung cancer with a polyclonal antibody raised against a 20-mer peptide of the putative high-affinity laminin receptor of 67 kDa (Wewer et al: Cancer Res 47: 5691-5698, 1987). As a result, immunoreactivity was recognized specifically in cancer cells both in freshly-prepared cell samples and in paraffin-embedded tissue specimens. It was shown that immunodetection of the laminin receptor polypeptide with this antipeptide antibody could be applied to diagnostic use for lung cancer. The results also suggest that the laminin receptor polypeptide is not necessarily a membrane-associated protein and may function without further processing to the 67 kDa-laminin receptor.

Variety of laminin expressions in murine neoplastic cell-lines - neuroblastoma na cells produce only laminin-b2 chain.

In the present study, we investigated the expression of laminin in three murine neoplastic cell lines; 3LL-SA (Lewis lung carcinoma), NA (neuroblastoma) and F9 (teratocarcinoma). Both Western and Northern blot analyses demonstrated that parietal endoderm-like F9 expressed three laminin chains A, B1 and B2. On the other hand, 3LL-SA cells synthesized two laminin chains B1 and B2, and NA cells only B2 chain. The analyses of the restriction fragment length polymorphism indicated that the genes for coding regions of all chains were present and grossly intact both in 3LL-SA and in NA just as in F9. These findings suggest that expression of laminin seems to be transcriptionally regulated in each neoplastic cell line specifically. Since these cell lines produce different forms of laminin, they can be used for investigation of the multifunctions of laminin molecule.

Pattern of fibronectin distribution in human lung cancer.

The pattern of fibronectin (FN) distribution in human lung cancer was studied by indirect immunofluorescent staining, and by the peroxidase-antiperoxidase method in a total of 60 surgical specimens. They comprised 8 small cell carcinomas, 4 large cell carcinomas, 19 squamous cell carcinomas, 28 adenocarcinomas, and 1 adenoid cystic carcinoma. Of the 60 specimens 13 were FN-positive. They included 4 large cell carcinomas, 4 small cell carcinomas, 3 poorly differentiated squamous cell carcinomas, and 2 poorly differentiated and 1 moderately differentiated adenocarcinomas. On the other hand, none of the well differentiated carcinomas was FN-positive around tumor cells. Our data suggest that undifferentiated, or poorly differentiated carcinomas of the lung tend to be FN-positive.

Comparative study of carbohydrate-protein complexes. II. Determination of hydroxylysine and its glycosides in human skin and scar collagens by an improved method.

A modification of the existing methods for measuring hydroxylysine, galactosylhydroxylysine, and glucosylgalactosylhydroxylysine is described. The method is based on analysis with an automated amino acid analyzer using a conventional separation system for basic amino acids. The prior removal of acidic and neutral amino acids was necessary. This was achieved by passing an alkaline hydrolysate of collagen through a column of Amberlite CG-120, Type II (H+) and washing the column with 8% aqueous pyridine. A basic fraction containing the hydroxylysine compounds was then recovered from the column by elution with 3 M NH4OH. Model experiments showed that hydroxylysine and its glycosides could be analyzed with an hour and that recoveries exceeded 90%. This method was applied to human tissues to investigate whether the dermal scar is different in collagen composition from normal skin. With the limited number of samples analyzed, the data suggested that long-standing scar tissues reverted to a composition similar to that of normal skin. The composition of hydroxylysine-linked carbohydrate units is also discussed on the basis of the age-related change.

Hormonal effects on the sulfation of sulfated glycoprotein in a particulate fraction of the endometrium of rabbit uterus.

A particulate fraction was separated from endometrial scrapings of the uterus of hormone- or sham-treated ovariectomized rabbit. The effects of estrogen and progesterone on the incorporation of [35S]sulfate from 3'-[35S]phosphoadenosine 5'-phosphosulfate (PAPS) into endogenous acceptors in the particulate fraction were investigated. Estrogen increased the incorporation of [35S]sulfate, but progesterone suppressed this effect. The results of DEAE-Sephadex A-25 (Cl-form) column chromatography of the pronase digest of the 35S-labeled substances indicated that the fraction eluted with 0.9 M NaCl (0.9 Fr) was most sensitive to the hormones. The major component in 0.9 Fr was resistant to crude heparinase, whereas the minor component was susceptible to this enzyme. The present observation, together with previous findings, suggested that the former was sulfated glycopeptide and the latter heparan sulfate. The results of the present study indicated that PAPS can serve as the direct "activated" sulfate donor in the enzymatic sulfation of sulfated glycoprotein in the particulate fraction, that the sulfation is greatly stimulated by pre-treatment of the rabbit with estrogen, and that the estrogen effect is suppressed by progesterone.

High-performance liquid chromatography of pyridylamino derivatives of unsaturated disaccharides produced from chondroitin sulfate isomers by chondroitinases.

A sensitive method was developed for the separation and quantitation of four unsaturated disaccharides (delta Di-0S, delta Di-4S, delta Di-6S, and delta Di-diS) by high performance liquid chromatography. The unsaturated disaccharides were coupled with a fluorescent compound, 2-aminopyridine. Complete separation of the resulting pyridylamino derivatives was achieved on a column of muBondapak-C18 with 8 mM KH2PO4-Na2HPO4 (pH 6.0)/methanol (30/l, by volume) as a mobile phase. There was a linear relationship between the fluorescence emission (peak height), and the amount of each authentic disaccharide used for the coupling reaction. This method was applied to analyze commercially available chondroitin sulfates A and C, dermatan sulfate, and urinary glycosaminoglycans obtained from patients with mucopolysaccharidosis after digestion with chondroitinases. The data indicated that the present method is useful for the separation and quantitation of nmol-pmol levels of the unsaturated disaccharides produced from chondroitin sulfate isomers by chondroitinases and can be used for their structural characterization.

Interaction of fibronectin and its proteolytic fragments with hyaluronic acid.

The interaction of porcine plasma fibronectin and its proteolytic fragments with hyaluronic acid was investigated by affinity chromatography using hyaluronic acid-linked Sepharose 4B. Hyaluronic acid was found to interact with all major fragments including the gelatin-binding polypeptide which has no affinity for heparin. A difference between hyaluronic acid and heparin was also noted in the relative interaction with two larger fragments. This type of multiple interaction may account for the affinity for hyaluronic acid strong enough to prevent the elution of fibronectin from the hyaluronate-column with a buffer containing 2 M NaCl.

Location of the essential thiol of porcine liver cathepsin B.

Porcine liver cathepsin B, a thiol enzyme, exists in at least three forms. While Form III is a single chain polypeptide, two peptide chains with molecular weights of 258000 and 4,000 are noncovalently bound together in Form I and Form II. The present study showed that aminoterminal sequences of Form III and the 4,000-dalton peptide isolated form Form II are identical. The 4,000-dalton peptide contained three cysteine or half-cystine residues, one of which was demonstrated to be essential for the enzyme activity by an incorporation study with [14C]iodoacetate. It was also shown that the 4,000-dalton peptide of the activated enzyme contained one cysteine and one cystine residue.