Human lung adenocarcinoma cell lines with different lung colonization potential (LCP), and a correlation between expression of sialosyl dimeric Le(x) (defined by MAb FH6) and LCP

Dual Role of the Extracellular Domain of Human Mucin MUC1 in Metastasis

Human mucin MUC1 plays an important role in cancer development. The increased level of this molecule expression during cancer cell progression induces metastasis and is associated with poor prognosis for patients. There is a large body of experimental data on the role of various functional domains of human mucin MUC1 in metastasis. While, the cytoplasmic domain determined to play a definitive role, the influence of extracellular domain on cancer cell invasiveness still remains unclear. The present paper reveals that the extracellular domain of MUC1 molecule consists of two functional subdomains-the region of tandem repeats (TR) and the region of irregular repeats (IR). We demonstrate the ability of each of these subdomains to alter the invasiveness of cancer cells. The presence of the MUC1 molecules containing TR subdomain (MUC1-TR) on the surface of low-invasive cancer cells leads to the increase in their transendothelial migration potency, while the addition of the IR subdomain to the MUC1-TR molecule (MUC1-IR-TR) restores their natural low invasiveness. J. Cell. Biochem. 118: 4002-4011, 2017. © 2017 Wiley Periodicals, Inc.

Resolving conflicting data on expression of the Tn antigen and implications for clinical trials with cancer vaccines

The tumor-associated Tn antigen has been investigated extensively as a biomarker and therapeutic target. Cancer vaccines containing the Tn antigen as a single tumor antigen or as a component of a polyvalent vaccine have progressed into phase I and II clinical trials. One major focus of Tn-based vaccines is the treatment of prostate cancer patients. Although expression of the antigen on prostate tumors is a critical prerequisite, previous reports investigating Tn expression in prostate tumors have produced conflicting results. Using a combination of immunohistochemistry and carbohydrate microarray profiling, we show that only 4% to 26% of prostate tumors express the Tn antigen. Based on our results, the majority of prostate cancer patients do not express the appropriate antigen. Therefore, efforts to preselect the subset of prostate cancer patients with Tn-positive tumors or apply Tn vaccines to other cancers with higher rates of antigen expression could significantly improve clinical response rates. Because conflicting information on carbohydrate expression is a general problem for the field, the approach described in this article of analyzing antigen expression with multiple antibodies and using carbohydrate microarray profiles to interpret the results will be useful for the development of other carbohydrate-based cancer vaccines and diagnostics.

Is Sialyl Lewis x antigen expression a prognostic factor in patients with breast cancer?

Sialyl Lewis x (sLex) carbohydrate antigen acts as an adhesion molecule expressed on the surface of cancer cells and is the most important ligand of the selectins present on endothelial cells. sLex expression was correlated to the metastatic potential of breast cancer. The aim of the present work was to evaluate the prognostic value of sLex in a series of breast carcinomas with long-term follow-up. A total of 127 consecutive patients with primary breast cancer were enrolled and followed for a median of 140 months. Tumor grade, mitotic index, histotype, vascular invasion, and tumor extension and sLex were recorded and used in multivariate analysis. sLex antigen was expressed in 37 specimens (21%). Survival was similar for sLex-positive and sLex-negative tumors (62% vs 60%) for overall survival and for disease-free survival (59% vs 56%). Expression of sLex antigen in breast cancer is not associated with breast cancer survival.

Evaluation of SAT-1, SAT-2 and GalNAcT-1 mRNA in colon cancer by real-time PCR

By qualitative and quantitative PCR, we evaluated the expression of three messengers coding for SAT-1, SAT-2 and GalNAcT-1 in human samples of intestinal cancer and some cell lines (breast cancer and melanomas). Qualitative PCR demonstrated, in human tissues but not in the cell lines examined, the presence of an mRNA that lacks hexon 3; experiments performed on transfected SKMEL-28 excluded a regulative role of this noncanonical mRNA. Data from real-time PCR, statistically analysed by ANOVA indicated that the mRNA expression of all the considered glycosyltransferases (SAT-1, SAT-2 and GalNAcT-1) was significantly different in tumours versus their own control. The ganglioside patterns in the examined samples did not correlate with mRNA expression; this finding demonstrates that ganglioside expression is the result of a very complex balance between anabolic and catabolic enzyme activities. Although this study is still preliminary, it opens a new possibility for neoplastic prognosis finding potential molecular markers among the mRNAs that codify for glycosyltransferases.

Monocyte-derived microparticles may be a sign of vascular complication in patients with lung cancer

We measured and compared the levels of plasma monocyte-derived microparticles (MDMP) and platelet activation markers [plasma platelet-derived microparticles (PDMP), CD62P binding to platelets; plt-CD62P, CD63 binding to platelets; plt-CD63], to develop a better understanding of their potential contribution to vascular complications of lung cancer. The concentrations of MDMP and PDMP in lung cancer patients were significantly higher (P < 0.01) than those in normal subjects. Levels of plt-CD62P and plt-CD63 were significantly higher (P < 0.001 for each) in lung cancer patients than in controls. Levels of sE-selectin were also higher in lung cancer patients than in control subjects. MDMP correlated positively with plt-CD62P, plt-CD63, and PDMP with its relation to PDMP being particularly significant. The number of MDMPs and PDMPs are patients who are non-small cell lung cancer were significantly higher than that in small cell lung cancer patients. In addition, levels of sE-selectin were higher in non-small cell lung cancer than in small cell lung cancer patients. These findings suggest that elevated MDMPs may be a sign of vascular complication in lung cancer patients, particularly those who suffer from non-small cell lung cancer.

Sialosyl-Le(x) expression defines invasive and metastatic properties of bladder carcinoma

BACKGROUND

Two types of transitional bladder carcinoma have been distinguished based on macroscopic morphology: type A papillary carcinomas, with papillomatous surface outgrowth without infiltration into muscular layer, and type B nodular carcinomas, with a nonpapillomatous surface appearance, most of which display infiltrative growth through muscular layer, and some of which display lymphatic or blood-borne metastasis. However, there is no specific predictor at early stages for later invasive and metastatic clinical outcome of patients with type B tumors.

METHODS

The study included 1) glycosphingolipid (GSL) composition of type A and B tumors; 2) histologic and immunohistologic patterns of nodular (type B) bladder carcinoma from 44 patients based on a special sampling procedure termed whole-layer core biopsy (WLCB) using the antisialosyl-Le(x) (anti-SLe(x); SLe(x): NeuAcalpha3Galbeta4[Fucalpha3]GlcNAcbeta3Galbeta4GlcCer) SNH3 antibody or other antibodies; 3) comparison of the incidence of metastasis in patients with SNH3 positive versus SNH3 negative primary tumors and of 5-year survival curves; 4) comparison of bladder carcinoma cell lines from tumors with high versus low malignancy in terms of expression patterns of SLe(x), SLe(a), and other carbohydrates, E-selectin dependent adhesion, and transcript levels of five fucosyltransferases.

RESULTS

Anti-SLe(x) monoclonal antibody (mAb) SNH3 staining of WLCB samples from 44 type B tumors showed that the majority of tumors (n = 31 patients) were SNH3 positive and the minority (n = 13 patients) were SNH3 negative. SNH3 positive patients had more lymph node or blood-borne metastasis and lower 5-year and 7-year survival rates, as indicated by Kaplan-Meier curves (P = 0.001). Staining of samples with other antibodies, including FH6 and CA19-9, was not correlated with long-term survival. Determination of GSL composition in extracts showed that SLe(x) ganglioside was present in all three patients with nodular tumors but absent in all three patients with papillary tumors tested. Bladder carcinoma cell lines from invasive tumors that maintained their metastatic properties were SNH3 positive, showed high levels of alpha1,3-fucosyltransferase VI (FT-VI) and FT-VII, and displayed E-selectin dependent adhesion. Cell lines from noninvasive tumors or normal bladder epithelia were negative for SNH3 reactivity, FT-VI, and FT-VII, and E-selectin dependent adhesion.

CONCLUSIONS

SLe(x) expression in primary bladder carcinoma, defined by the mAb SNH3, is a predictor of invasive and metastatic outcome. No other carbohydrate epitope examined to date has equal prognostic value.

The glycosynapse

Physically distinguishable microdomains associated with various functional membrane proteins are one of the major current topics in cell biology. Glycosphingolipids present in such microdomains have been used as "markers;" however, the functional role of glycosyl epitopes in microdomains has received little attention. In this review, I have tried to summarize the evidence that glycosyl epitopes in microdomains mediate cell adhesion and signal transduction events that affect cellular phenotypes. Molecular assemblies that perform such functions are hereby termed "glycosynapse" in analogy to "immunological synapse," the membrane assembly of immunocyte adhesion and signaling. Three types of glycosynapses are so far distinguishable: (i) Glycosphingolipids organized with cytoplasmic signal transducers and proteolipid tetraspanin with or without growth factor receptors; (ii) transmembrane mucin-type glycoproteins with clustered O-linked glycoepitopes for cell adhesion and associated signal transducers at lipid domain; and (iii) N-glycosylated transmembrane adhesion receptors complexed with tetraspanin and gangliosides, as typically seen with the integrin-tetraspanin-ganglioside complex. The possibility is discussed that glycosynapses give rise to a high degree of diversity and complexity of phenotypes.

Traveling for the glycosphingolipid path

Our studies on glycosphingolipids (GSLs) were initiated through isolation and structural characterization of lacto-series type 1 and 2 GSLs, and globo-series GSLs. Lacto-series structures included histo-blood group ABH and I/i antigens. Our subsequent studies were focused on GSL changes associated with: (i) ontogenic development and differentiation; (ii) oncogenic transformation and tumor progression. Various novel types of GSLs such as extended globo-series, sialyl-Le(x) (SLe(x)), sialyl-dimeric-Le(x) (SLe(x)-Le(x)), dimeric-Le(x) (Le(x)-Le(x)), Le(y)-on-Le(x), dimeric-Le(a) (Le(a)-Le(a)), Le(b)-on-Le(a), etc. were identified as tumor-associated antigens. These studies provide an essential basis for up- or down-regulation of key glycosyltransferase genes controlling development, differentiation, and oncogenesis. GSL structures established in our laboratory are summarized in Table 1, and structural changes of GSLs associated with ontogenesis and oncogenesis are summarized in Sections 2 and 3. Based on these results, we endeavored to find out the cell biological significance of GSL changes, focused on (i) cell adhesion, e.g., the compaction process of preimplantation embryo in which Le(x)-to-Le(x), Gb4-to-GalGb4 or -nLc4 play major roles; and (ii) modulation of signal transduction through interaction of growth factor receptor tyrosine kinase with ganglioside, e.g., EGF receptor tyrosine kinase with GM3. Recent trends of studies on i and ii lead to the concept that GSL clusters (microdomains) are organized with various signal transducer molecules to form 'glycosignaling domains' (GSD). GSL-dependent adhesion occurs through clustered GSLs, and is coupled with activation of signal transducers (cSrc, Src family kinase, Rho A, etc.). Clustered GSLs involved in cell adhesion are recognized by GSLs on counterpart cells (carbohydrate-to-carbohydrate interaction), or by lectins (e.g., siglecs, selectins). Our major effort in utilization of GSLs in medical science has been for: (i) cancer diagnosis and treatment (vaccine development) based on tumor-associated GSLs and glycoepitopes; (ii) genetically defined phenotype for susceptibility to E. coli infection; (iii) clear identification of physiological E-selectin epitope (myeloglycan) expressed on neutrophils and myelocytes; (iv) characterization of sialyl poly-LacNAc epitopes recognized as male-specific antigens. Utilization of these GSLs or glycoepitopes in development of anti-adhesion approach to prevent tumor metastasis, infection, inflammation, or fertilization (i.e., contraceptive) is discussed. For each approach, development of mimetics of key GSLs or glycoepitopes is an important subject of future study.

Effect of hyperthermia on the viability and the fibrinolytic potential of human cancer cell lines

The effects of heat treatment on the viability and fibrinolytic potential of four cultured human carcinoma cell lines, fibrosarcoma cells (HT-1080), lung adenocarcinoma cells with highly metastatic potential (HAL-8), melanoma cells (Bowes) and osteosarcoma cells (NY), determined by measuring their levels of urokinase-type plasminogen activator (u-PA) and its specific receptor (u-PAR), were investigated by comparing them with those of human umbilical vein endothelial cells (HUVECs). HUVECs incubated at 43 degrees C for 120 min exhibited no decrease in viability but exhibited an increase in both u-PA and u-PAR. HT-1080 and HAL-8 showed a moderately high heat-resistance (viability, 60-90%) that correlated with the reduction of u-PAR but not u-PA. On the other hand, Bowes and NY cells, with poor heat-resistance (viability, 20-50%), exhibited stronger cell-associated u-PA activity when they survived at 43 degrees C for 120 min. Since the u-PA/u-PAR system is directly involved in the invasiveness and metastatic potential of carcinoma cells, hyperthermia would alter the biological activity of these carcinoma cells.

Identification of semaphorin E gene expression in metastatic human lung adenocarcinoma cells by mRNA differential display

Human lung adenocarcinoma cell lines HAL-8Luc and HAL-24Luc differ in their metastatic potential. HAL-8Luc cells metastasize to lungs when injected either intravenously or intramuscularly. in mice while HAL-24Luc cells do not. The differential display method is used to identify genes differentially expressed between the two cell lines and the findings are extensively discussed.

BACKGROUND

Lung cancer is the leading form of cancer in most countries, and metastasis is the main cause of death in oncological patients. The metastatic phenotype of tumor cells is the result of genetic events altering the RNA and protein expression of normal cells. Our objective was to identify genes expressed differentially between metastatic and nonmetastatic human lung adenocarcinoma cells that might be used as a prognostic factor.

METHODS

The differential display technique was used to compare the RNA expression patterns distinguishing metastatic (HAL-8Luc) and nonmetastatic (HAL-24Luc) human lung adenocarcinoma cells, two genetically close cell lines.

RESULTS

Differential expression of three cDNAs was confirmed by Northern blot analysis. Two sequences corresponding to a putative splicing factor and a proliferation-related factor cDNAs were underexpressed in the metastatic cells relative to the nonmetastatic ones. Interestingly, we found that human semaphorin E mRNA was several fold overexpressed in the metastatic cells. This recently identified gene encodes a protein whose expression has been related to several cell survival mechanisms as well as to immunosuppression.

CONCLUSION

Our results point to the relevance of semaphorin E in metastatic spread of human lung adenocarcinoma cells.

Overexpression of alpha(1,3)-fucosyltransferase VII is sufficient for the acquisition of lung colonization phenotype in human lung adenocarcinoma HAL-24Luc cells

Metastatic human lung adenocarcinoma HAL-8Luc cells display an enhanced expression of alpha(1,3)-fucosyltransferases (alpha(1,3)-Fuc-Ts) compared with their non-metastatic counterpart HAL-24Luc cells. This correlates with an increased surface expression of Lewis(x) (Le(x))- and Lewis(a) (Le(a))-related molecules and an in vitro enhanced adhesive capacity to E-selectin-expressing endothelial cells (Martin-Satué et al (1998). Cancer Res 58: 1544-1550). In the present work we have stably transfected HAL-24Luc cells with the cDNAs for the alpha(1,3)-Fuc-TIV and VII enzymes and analysed by flow cytometry the expression of Le(x), sialyl-Le(x), sialyl-Le(x) dimeric, Le(a) and sialyl-Le(a). Fuc-TVII transfectants exclusively overexpress sialyl-Le(x) while Fuc-TIV-transfected cells only overexpress the Le(x) oligosaccharide. We show that solely Fuc-TVII transfectants are able to adhere to interleukin-1beta-stimulated HUVEC monolayers. We also demonstrate that Fuc-TVII overexpression in HAL-24Luc cells is sufficient for the acquisition of the lung colonization phenotype. This is the first report directly showing the contribution of an alpha(1,3)-Fuc-T to the metastatic behaviour of human lung adenocarcinoma cells.

Identification of sialyl Lewis-x in squamous cell carcinoma of the head and neck

BACKGROUND

Sialyl Lewis-x (sLx) is a cellular adhesion molecule (CAM) that has been implicated in the inflammatory reaction and cancer metastasis. The sLx is the carbohydrate ligand of endothelial-selectin (E-selectin), an inducible vascular endothelial CAM. The role of sLx has been investigated in several cancers, and its presence has been correlated with advanced disease stage, decreased disease-free survival, and greater metastatic potential. A recent study has found that cultured head and neck (HN) squamous cell carcinoma (SCC) cell lines express sLx and that binding of these cells to cytokine activated endothelium correlates with the endothelial expression of E-selectin. The purpose of this study was to identify sLx in the tumors of patients with HNSCC and to see if the presence of sLx correlated with disease status.

METHODS

We performed immunohistochemical (IHC) staining to detect the sLx antigen using the monoclonal antibody (MAb) KM-93. Eighty-two specimens of HNSCC that were obtained at the time of resection or biopsy were analyzed for sLx staining patterns and intensities. The clinical outcomes of survival, disease-free interval, and incidence of distant metastasis were then assessed to determine whether there was a correlation with sLx tumor expression. In addition, we analyzed specimens from metastatic HNSCC sites for expression of sLx.

RESULTS

The sLx expression was identified in 62% of the primary tumor specimens and 87% of the metastatic tumor specimens analyzed by IHC. The staining pattern in the HNSCC tumors differed from that seen in normal squamous epithelium but was variable in both intensity and distribution. The sLx expression in the metastatic sites was higher than in the primary sites in 67% of the specimens (10 of 15). There was no correlation between sLx staining and disease status.

CONCLUSIONS

The results of this study demonstrate that sLx is present in HNSCC and supports the data that show that sLx may play a role in the metastasis of HNSCC. Future studies are warranted to evaluate the role of sLx, E-selectin, and other CAMs in HNSCC.

Metastatic potential of human CX-1 colon adenocarcinoma cells is dependent on the expression of sialosyl Le(a) antigen

Several lines of evidence indicate that sialosyl Le(a), tumor-associated carbohydrate antigen present on human colon carcinoma cells, is involved in formation of metastases. To study the role of this carbohydrate structure in development of metastases, we have used the clone of human colon carcinoma CX-1 cells transfected with antisense expression vector containing fragment of cDNA for alpha1,3/4-fucosyltransferase (FT III), which is involved in synthesis of sialosyl Le(a) tetrasaccharide. It has been reported previously that, in contrast to the parental cells, the antisense-transfected CX-1.1AS5 cells do not express sialosyl Le(a) and do not adhere to E-selectin-expressing CHO cells. In the present work we have studied the formation of liver metastases by CX-1.1AS5 cells after their orthotopic or intrasplenic implantation into athymic nu/nu mice. After orthotopic implantation of sialosyl Le(a)-negative colon carcinoma CX-1.1AS5 cells, the number of mice with liver metastases was markedly lower (21% of mice) in comparison with their number after implantation of the parental CX-1.1 cells (86% of mice). However, no differences in ability to form colonies in liver were observed between parental CX-1.1 cells and antisense-transfected CX-1.1AS5 cells after intrasplenic inoculation. The liver metastases were formed in 89% and 84% of mice, respectively. Our data support the thesis on the importance of sialosyl Le(a) antigen expression in the development of liver metastases by colon cancer cells, and indicate the role of transplantation route and primary tumor localization in formation of metastases.

Immunohistochemical expression of the sialyl Lewis x antigen on gastric cancer cells correlates with the presence of liver metastasis

The expression of the sialyl Lewis x antigen (sLe(x)) on surgical specimens of primary gastric cancer correlates with the degree of differentiation and synchronous and metachronous liver metastasis. Multivariate analysis by means of Quantification theory II revealed that sLe(x) expression was an independent risk factor for liver metastasis from gastric cancer.

Dimeric sialyl-Le(x) expression in gastric carcinoma correlates with venous invasion and poor outcome

BACKGROUND & AIMS

High expression of sialyl-Le(x) in tumors of different organs correlates with hematogenous metastasis and adverse outcome. Dimeric sialyl-Le(x) expression in gastric carcinoma was evaluated, and its prognostic significance within this setting was determined.

METHODS

Dimeric sialyl-Le(x) immunohistochemical expression in 97 gastric carcinomas was analyzed using the FH6 monoclonal antibody. Scoring was based on the percentage of immunoreactive cells: negative, low expression (< or = 25%), and high expression (> 25%).

RESULTS

Immunoreactivity was observed in 45 cases (46.4%), encompassing 27 and 18 cases with low and high expression, respectively. Significant relationships were found between dimeric sialyl-Le(x) expression and venous invasion (P = 0.0025) and histological classification (P = 0.05). No correlation was observed with other clinicopathologic features. Patients with tumors showing high expression of dimeric sialyl-Le(x) had a significantly shorter survival time than those with low or no expression (P = 0.03). By multivariate analysis, pathological TNM (pTNM) staging and venous invasion emerged as independent prognostic factors in the whole series. Within the group of patients with tumors in pTNM stages II and III, dimeric sialyl-Le(x) was the only independent prognostic factor.

CONCLUSIONS

High expression of dimeric sialyl-Le(x) correlates with venous invasion and poor outcome in gastric carcinoma.

Lactoseries carbohydrate epitopes in the vertebrate retina

The distribution of N-acetyl-lactosamine (NALA), a cell-surface carbohydrate epitope of the lactoseries, has been studied in the retina of representative species of all vertebrate classes by light microscope immunohistochemistry. In only some species of different classes (fish, amphibia and mammals) was NALA expression detected, and in these animals the distribution showed profound interspecies variability. In fishes and amphibia in which NALA was present, patterns ranged from single immunopositive cells to homogeneous labelling of cell layers. In mammals, NALA was found only in retinas that are cone dominated (tree squirrel and primates). In the tree squirrel, there was a dense cellular staining of the photoreceptor cell layer; whereas in primates, the carbohydrate epitope occurred only on some photoreceptor cells. From these receptor cells, positive axons could be traced to the inner plexiform layer. In spite of the profound interspecies differences, NALA is not randomly expressed, as its exclusive expression in mammals with cone-dominated vision indicates. The suggestion of a functional relevance for NALA glycosylation of retinal cells is supported by the labelling pattern for HNK-1 in these species, which was different from the pattern found in rod-dominated mammalian retinas.

Soybean agglutinin binding as a useful prognostic indicator in stomach cancer

Soybean agglutinin (SBA)-binding carbohydrate expression was studied immunohistochemically in 353 primary gastric carcinomas. The overall rate of positive SBA staining was 23% (81/353), and positive SBA staining was significantly correlated with tumor size, macroscopic tumor type, depth of invasion, lymph node metastasis, and venous invasion (P < 0.05). Moreover, patients with tumors that were immunoreactive for SBA demonstrated significantly higher survival (P < 0.01). From these findings we conclude that careful follow-up and intense postoperative therapy are required for patients with gastric cancers that lack immunoreactivity for SBA.

Identification, purification and analysis of a 55 kDa lectin binding glycoprotein present in breast cancer tissue

The Helix pomatia agglutinin (HPA)-binding glycoproteins from primary breast cancers and their metastases were compared with appropriate normal control tissues on Western blots. From these studies a single glycoprotein of 55 kDa was found to bind HPA in tumours but not in normal control tissues. The glycoprotein was identified by protein sequencing as being homologous to human immunoglobulin heavy chain variable region. Subsequent immunostaining showed it to be immunoglobulin subclass A. IgA1 was purified from both tumour and normal tissue by affinity chromatography. It was demonstrated that IgA1 from tumour tissue bound HPA whereas IgA1 from normal tissue did not. The oligosaccharides were cleaved from the protein backbone and the glycans from the HPA-binding glycoform of IgA1 were compared with those from normal human IgA1. IgA1 from tumour tissue appears to be associated with an HPA-binding glycan which is not present on the normal tissue-derived IgA1.

Enhanced urokinase-type plasminogen activator activity by extracellular matrix protein obtained from highly metastatic human lung adenocarcinoma cell line

A protein which enhanced urokinase-type plasminogen activator (u-PA) activity was purified from the extracts of extracellular matrix of highly metastatic cell line HAL-8 derived from human lung adenocarcinoma. The protein showed a single band with molecular weight of 65 kDa after the purification by Sephadex G-150 and diethylaminoethyl-cellulose followed by reversed phase separation in a high performance liquid chromatography system. The purified protein in the immobilized conditions enhanced u-PA activity in both plasminogen activation and S-2444 amidolysis by 4.6- and 2.8-fold increases in the second order rate constants (Kcat/K(m)), respectively. This protein was related to neither plasminogen nor single-chain u-PA by the immunological studies and with respect to retention time on reversed phase analysis. These results suggest that the purified material acts as an enhancer of u-PA in extracellular matrix of the cancer cells, inducing an effective tissue destruction and cell invasion and possessing a highly metastatic potential.

Cell surface carbohydrates as prognostic markers in human carcinomas

Tumour development is usually associated with changes in cell surface carbohydrates. These are often divided into changes related to terminal carbohydrate structures, which include incomplete synthesis and modification of normally existing carbohydrates, and changes in the carbohydrate core structure. The latter includes chain elongation of both glycolipids and proteins, increased branching of carbohydrates in N-linked glycoproteins, and blocked synthesis of carbohydrates in O-linked mucin-like glycoproteins. In mature organisms, expression of distinct carbohydrates is restricted to specific cell types; within a given tissue, variation in expression may be related to cell maturation. Tumour-associated carbohydrate structures often reflect a certain stage of cellular development; most of these moieties are structures normally found in other adult or embryonic tissues. There is no unique tumour carbohydrate structure, since certain structures which are tumour-related in one organ may be normal constituents of other tissues. Tumour-associated carbohydrate changes have been used in the diagnosis of human cancers. Recently, however, it has been demonstrated that the expression of some carbohydrate structures is associated with prognosis. Tn, sialyl-Tn, and T are cell membrane-bound mucin-like carbohydrate structures that may be expressed in tumours due to blocked synthesis of the core carbohydrate chain of mucin-like structures. Their expression is strongly associated with prognosis in certain tumours, but the biological relationship between their expression and tumour progression is at present unknown. The blood group-related carbohydrate structures Le(x), sialyl-Le(x), ABH, and Le(y) are examples of terminal carbohydrate structures which are related to tumour prognosis. These structures are of increasing interest since they may function as adhesion molecules; adhesion of tumour cells to endothelial cells of blood vessels may be mediated by an interaction between sialosyl-Le(x) and E-selectin and studies indicate that Le(y) is related to cell motility. These findings are now the basis for tumour therapeutic experiments.

Selectin ligands on human melanoma cells

Twelve established human melanoma lines were screened for surface expression of the carbohydrate antigens Lewisa (Lea), sialyl Lewisa (SLea), dimeric sialyl Lewisa (diSLea), sialyl LewisX (SLex) and dimeric sialyl LewisX (diSLeX). None of the lines expressed SLex, but 11/12 were positive for diSLeX and 7/12 were positive for SLea. Although both diSLeX and SLea have been reported to bind to E-selectin, none of the melanoma lines exhibited E-selectin-dependent adhesion to activated human umbilical vein endothelial cells (HUVECs). Three melanoma lines infected with a retroviral vector carrying the cDNA for the human Lewis fucosyltransferase (FucT-III) subsequently expressed SLeX at their cell surface and exhibited E-selectin-dependent adhesion to activated HUVECs. Treatment of these transduced cells with inhibitors of O-linked or N-linked protein glycosylation significantly inhibited E-selectin-mediated adhesion, though fluorescence-activated cell sorter analysis indicated no decrease in cell surface expression of SLeX, Slea or diSLeX. This suggests that the majority of SLeX/SLea-type glycans endogenously produced by human melanoma cells are not protein-associated and do not mediate E-selectin-dependent adhesion. These results support the hypothesis that E-selectin-dependent adhesion requires presentation of SLeX-type moieties on appropriate glycoproteins.

Expression of alpha-GalNAc glycoproteins by breast cancers

The expression of complex carbohydrates recognised by Helix pomatia lectin (HPA, nominal monosaccharide binding specificity alpha-GalNAc) has been shown to predict unfavourable prognosis in breast and other cancers. It has been suggested that the prognostic significance of HPA binding may be through recognition of either Tn epitope (alpha-GalNAc-O-serine/threonine) or blood group A antigen (terminal alpha-1-->3GalNAc attached to the basic H-antigen, Fuc-alpha-1-->2-Gal-beta-1-->4(or 3) GlcNAc-->R). In this study, the expression of glycoproteins terminating in alpha-GalNAc residues was investigated immunohistochemically using HPA and two monoclonal antibodies--BRIC 66 (anti-alpha-GalNAc) and BRIC 111 (anti-Tn). In paraffin sections, 74/87 (85%) of breast cancers expressed HPA-binding ligands, while 28/87 (32%) were positive for BRIC 66 binding and 25/87 (29%) expressed Tn. Distribution of staining patterns were distinctive and different with the three markers. BRIC 66, BRIC 111 and HPA binding to glycoproteins derived from breast cancer homogenates and to blood group A and Tn positive glycoproteins in Western blots confirmed the immunohistochemistry data. The results suggest that the prognostic significance of HPA binding in breast cancer is unlikely to be simply through recognition of blood group A antigen or Tn epitope on cancer cells. Breast cancers may express a complex profile of related but distinct glycans sharing similar terminal immunodominant sugar GalNAc, which may be implicated in aggressive biological behaviour.

Establishment and characterization of a new human lung poorly differentiated adenocarcinoma cell line, GLL-1, producing carcinoembryonic antigen (CEA) and CA19-9

A new human lung poorly differentiated adenocarcinoma cell line producing carcinoembryonic antigen (CEA) and CA19-9, designated GLL-1, was established from a serial xenograft established in our laboratory. In this paper, we investigated the characteristics of GLL-1 cells. The cell line grew in a monolayer and had a polygonal epithelioid appearance in phase-contrast microscopy. The doubling time of GLL-1 cells during exponential growth was approximately 28 h in RPMI-1640 with 10% fetal calf serum. Positive reactions for CEA and for CA19-9 were seen within the cytoplasm of GLL-1 cells by immunohistochemical staining. In log phase, the fractions for G0/G1, S and G2/M were 76.2%, 20.0% and 3.8%, respectively. Chromosome analysis revealed that GLL-1 cells contained the modal number of 72 chromosomes (range 66-97). GLL-1 cells exhibited numerous numerical and structural abnormalities. The Do value for radiation sensitivity, calculated by taking the reciprocals of the slope of the radiation dose response curve, was 109 cGy. The extrapolation number (n) for the radiation response curve was 1.57. Tumor take was observed in nude mice inoculated subcutaneously in the back with 2 x 10(6) GLL-1 cells. The histopathological features of the tumor induced by inoculation of GLL-1 cells were also the same as the original lung cancer.

Involvement of N-acetyl-lactosamine-containing sugar structures in the liver metastasis of mouse colon carcinoma (colon 26) cells

Histochemical aspects of the process of experimentally induced metastasis were examined by light and electron microscopy with labelled lectins employed as a probe. Mouse colon carcinoma cells (colon 26) were injected into the spleen of Balb/c mice and liver metastasis was induced. Among the lectins tested, Erythrina cristagalli agglutinin (ECA) stained the metastasized colon 26 cells strongly compared with the heterogeneous and faint staining in non-metastasized tumour foci in the spleen or in the subcutaneous space. Other lectins, such as Phaseolus vulgaris leucoagglutinin (PHA-L), Phaseolus vulgaris erythroagglutinin (PHA-E) and Datura stramonium agglutinin (DSA), having specificity for branched complex type sugar chains, did not show any differences between metastasized cells and non-metastasized tumour foci. In addition, N-acetyl-lactosamine, a specific inhibitor of ECA binding, significantly inhibited the attachment of suspended colon 26 cells to sectioned unfixed normal liver tissue. These results indicate that the expression of galactose (Gal) beta 1-4 N-acetyl-glucosamine (GlcNAc) residues of branched complex type sugar chains having specificity for ECA are important for the interaction process of carcinoma cells with hepatic cells in the process of liver metastasis.

Biosynthesis of sialyl-oligomeric-Lewisx and VIM-2 epitopes: site specificity of human milk fucosyltransferase

In a previous study we have established the order of fucosylation of a trimer of Gal beta 1-->4GlcNAc (LacNAc) linked to a synthetic hydrophobic aglycon, (LacNAc)3-[(trifluoroacetamido)phenyl]ethyl, by a partially purified alpha 3-fucosyltransferase preparation from normal human milk [De Vries, Th., Norberg, T., Lönn, H., & van den Eijnden, D. H. (1993) Eur. J. Biochem. 216, 769-777]. Using the same fucosyltransferase preparation, we have now studied the fucosylation of the oligosaccharide NeuAc alpha 2-->3(LacNAc)3-Me. This compound was generated from the asialo analogue by use of an alpha 3-sialyltransferase preparation from human placenta. The location of the fucose residues in the monofucosylated and difucosylated intermediate products was determined by analyzing digests obtained after endo-beta-galactosidase treatment using HPLC on amino-bonded silica. In addition, the fucosylated NeuAc alpha 2-->3(LacNAc)3-Me structures were characterized by high-pH anion-exchange chromatography with pulsed amperometric detection and were identified by 400-MHz 1H-NMR spectroscopy. Intermediate products included oligosaccharides that contained the VIM-2, sialyl-LewisX, and sialyl-dimeric-LewisX epitopes. The final product was identified as the sialyl-trimeric-LewisX oligosaccharide. Kinetic analysis of the fucosylation reaction indicated that there is a significant difference in the rate of transfer of the first, second, and third fucose residues onto the acceptor molecule. Transfer of the first fucose occurred to either of the three GlcNAc residues in NeuAc alpha 2-->3(LacNAc)3-Me with only a modest preference for the proximal and medial residues. A similar slight preference for these GlcNAc residues was found for the attachment of the second fucose residue.(ABSTRACT TRUNCATED AT 250 WORDS)

An immunohistochemical employer monoclonal antibodies against Le(a), sialyl Le(a), Le(x), and sialyl Le(x) antigens in primary colorectal, carcinomas and lymph node and hepatic lesions

The immunohistochemical expression of sialylated and non-sialylated forms of both Le(x) and Le(a) were studied in 87 carcinomas and 42 normal mucosal specimens of colon and rectum, as well as in 32 metastatic lymph nodes and 9 hepatic lesions, using an indirect immunoperoxidase staining. Their antigens were expressed in normal mucosa with the following frequencies: Le(a), 95.2% (40/42); sialyl Le(a), 88.1% (37/42); Le(x), 95.2% (40/42); and sialyl Le(x), 17.0% (7/42), whereas in carcinomas, the respective rate of frequency were: 78.2% (68/87); 78.2% (68/87); 90.8% (79/87); and 93.1% (81/87). Sialyl Le(x) antigen showed the highest tumor specificity compared to other antigens. In three normal mucosal specimens and four carcinomas with Le(a-b-) phenotype, the expression of type 1 antigens (Le(a) and sialyl Le(a)) was not consistent, whereas type 2 antigens (Le(x) and sialyl Le(x)) were consistently observed in carcinomas. The staining of type 1 antigens and Le(x) was decreased in metastatic lesions compared with primary carcinomas, whereas sialyl Le(x) antigen had the same positive-staining rate in both. Metastatic carcinoma expressed the sialylated form more predominantly than the non-sialylated form in type 2 antigens whereas the opposite result was observed in type 1 antigens. These results suggested that: (a) sialyl Le(x), defined by monoclonal antibody CSLEX1, may be useful as a tumor-associated antigen in colorectal carcinoma, and (b) the alteration of Lewis-related carbohydrate antigens in cancer cell membranes, including sialylation and/or aberrant glycosylation, may be related to metastatic behavior.

Fucosyltransferase-producing sialyl Le(a) and sialyl Le(x) carbohydrate antigen in benign and malignant gastrointestinal mucosa

BACKGROUND

Sialyl Le(a) antigen and sialyl Le(x) antigen are cancer-associated carbohydrate antigens. Previous immunohistologic and immunochemical studies have shown that these antigens are preferentially expressed in gastric cancer and colonic cancer and that they possibly are related to the metastatic potential of the cancer cells. The biosynthesis of these antigens is completed by fucosyltransferases, but it has not been reported how fucosyltransferases control the expression of these carbohydrate antigens concerning the invasive potential of the cancer.

METHODS

The authors established an assay system for measuring the activity of alpha 1-->4 fucosyltransferase (sialyl Le(a) synthase) and alpha 1-->3 fucosyltransferase (sialyl Le(x) synthase) with a high-pressure liquid chromatography system (HPLC). The activity was measured in various parts of normal and cancerous gastric and colonic tissue and compared with the expression of sialyl Le(a), sialyl Le(x), Le(a), and Le(x) antigens determined in a solid-phase enzyme-linked immunosolvent assay (EIA).

RESULTS

Sialyl Le(a) synthase was detected in most normal or malignant mucosa of gastric and colonic tissues, regardless of anatomic locations. Sialyl Le(x) synthase activity generally was low in the normal gastric mucosa, whereas the activity was higher in 77% (7 of 9) of gastric cancer tissues than in corresponding normal tissues with enhanced expression of sialyl Le(x) antigen in most patients (5 of 7). In the large intestine, the activity of sialyl Le(a) synthase and sialyl Le(x) synthase was correlated. Although enhanced expression of sialyl Le(x) in colonic cancer was observed in 86% (12 of 14) of all patients, concomitant higher sialyl Le(x) synthase activity than that in normal tissue was observed in only 58% (7 of 12) of patients.

CONCLUSIONS

The expression of sialyl Le(a) and sialyl Le(x) antigens in the stomach and the colon was not controlled solely by fucosyltransferases but by a more complicated system involving other glycosyltransferases.

Immunohistochemical expression of sialyl Lex antigen in relation to survival of patients with colorectal carcinoma

BACKGROUND

The alterations of carbohydrate chains in cancer cell membrane can be related, not only to the formation of tumor-associated antigens, but also to cell biologic significance. There is, furthermore, a possibility of their relationship to tumor metastatic behavior and subsequent survival of patients with cancer. Recent clinical studies elucidated that a carbohydrate antigen, sialyl Lex, is a useful tumor marker in colorectal cancer. However, the sialyl Lex antigen immunoreactivity in colorectal carcinoma in relation to patient survival is unknown. The aim of the study was to elucidate whether sialyl Lex expression in tumors was correlated with patient survival.

METHODS

Immunohistochemical expression of sialyl Lex antigen, as detected by monoclonal antibody CSLEX1, was studied in 175 specimens of primary colorectal carcinoma from 120 patients who received radical surgery.

RESULTS

The positive expression of sialyl Lex was observed in 87 of 120 patients (72.5%). There was no statistically significant association between the negative or positive of sialyl Lex and clinicopathologic factors, excluding Dukes stage and histologic type. The difference between overall 5-year survival of patients with sialyl Lex-negative tumors and that of patients with sialyl Lex-positive tumors (81.2% versus 60.6%) was statistically significant (P = 0.0263). In proportion to staining intensity that was expressed as a score based on the percentage of the total field stained positive with CSLEX1, 5-year survival of patients indicated a worse outcome (P = 0.0113). The prognostic value was then studied in a Cox regression model. Dukes stage had the strongest association with patient survival, whereas sialyl Lex expression was found to be the second-ranking parameter.

CONCLUSIONS

When examining the expression of sialyl Lex antigen, as detected by monoclonal antibody CSLEX1, clinically useful information for patient survival after radical resection of colorectal cancer is given.

Platelets and cancer metastasis: a causal relationship?

Cancer metastasis is a highly coordinated and dynamic multistep process in which cancer cells undergo extensive interactions with various host cells before they establish a secondary metastatic colony. Ample morphological studies have documented the close association of circulating tumor cells with host platelets. Several lines of evidence provide strong support for the concept that tumor cell-platelet interactions (i.e., TCIPA) significantly contribute to hematogenous metastasis. Clinically, cancer patients with advanced diseases are characterized by a variety of thromboembolic disorders including thrombocytosis. Pharmacologically, various anti-platelet agents/anticoagulants have demonstrated potent inhibitory effects on tumor cell-platelet interactions as well as spontaneous or experimental metastasis. Experimentally, interference with many of the intermediate steps of tumor cell-platelet interactions has resulted in diminished platelet aggregation induced by tumor cells and blocked cancer metastasis. Platelet interaction with tumor cells is a sequential process which involves two general types of mediators, i.e., membrane-bound molecules (adhesion molecules) and soluble release products. alpha IIb beta 3 integrin receptors present on both platelets as well as on tumor cells and 12(S)-HETE, a 12-lipoxygenase metabolite of arachidonic acid, are prototypical examples of each category. Mechanistically, platelets may contribute to metastasis by: (1) stabilizing tumor cell arrest in the vasculature, (2) stimulating tumor cell proliferation, (3) promoting tumor cells extravasation by potentiating tumor cell-induced endothelial cell retraction, and (4) enhancing tumor cell interaction with the extracellular matrix.

Occurrence and specificities of α3-fucosyltransferases

The Le(x) (CD15) carbohydrate antigen and sialylated and oligomeric derivatives thereof have been implicated in cell adhesion processes. Expression of these antigens is developmentally regulated and (re)occurrence of several members of this group has been reported in malignant transformation of cells. Studies on the enzymology and genetics of alpha 3-fucosyltransferases, glycosyltransferases that play a key role in the biosynthesis of these antigens, would yield insight in the regulation of expression of these carbohydrate structures. In this paper the existing literature on these enzymes is reviewed and placed in the context of cell adhesion and malignancy.