Enzyme activity in invasive tumors of human breast and colon

The salubrious effect of tamoxifen [correction of Tamaxifen] on serum marker enzymes, glycoproteins, and lysosomal enzymes level in breast cancer woman

Tumour markers correlate strongly with prognosis based on tumour burden and surgical resectability. If chemotherapy is extremely effective in certain stage of the disease, the sensitive marker may be of great use in monitoring disease response and drug treatment. Hence, this study was launched to evaluate the changes in tumour marker enzymes like lactate dehydrogenase (LDH), glutamate oxaloacetate transaminase (SGOT), glutamate pyruvate transaminase (SGPT), alkaline phosphatase, and acid phosphatase in before and after 3 and 6 months tamoxifen treated breast cancer patients. In addition, the changes in serum glycoproteins viz., hexose, hexosamine, and sialic acid and lysosomal enzymes such as N-acetyl-beta-D-glucosaminidase, beta-D-galactosidase, and beta-D-glucuronidase were analysed in these patients. These values were compared with their age matched healthy control subjects. At 6 months evaluation, the tamoxifen treated postmenopausal breast cancer women showed a statistically significant decreased (p < 0.001, 0.05 respectively) levels of LDH, SGOT, SGPT, alkaline and acid phosphatases than their baseline values. Similarly, the levels of hexose, hexosamine, and sialic acid and N-acetyl-beta-D-glucosaminidase, beta-D-galactosidase, and beta-D-glucuronidase were decreased significantly (p < 0.001) in tamoxifen received postmenopausal women. The result of this study suggested that tamoxifen potentially retard the metastasis of breast cancer as well as the bone demineralisation in postmenopausal breast cancer women. Thus, tamoxifen may also have its antitumour activity through its beneficial effects on tumour marker enzymes and serum proteins in breast cancer women.

Sialic acid concentration in different stages of malignant lymphoma and leukemia in children

Sialic acid concentration in the blood serum of 104 children suffering from leukemia and malignant lymphomas was determined. A significant higher concentration of sialic acid was found at the onset of the disease, compared to the controls. In the group of children suffering from acute lymphoblastic leukemia a dependence was noted between the stage of the disease and the concentration of sialic acid in the serum. The high concentration of sialic acid at the onset of the disease, although decreasing during treatment, rose again during relapses of the disease. It seems that determination of sialic acid concentration may be useful in monitoring treatment.

Surface-associated glycosyltransferase activities in rat Sertoli cells in vitro

We have previously demonstrated fucosyltransferase (FT) activity on mouse germ cell surfaces at different stages of spermatogenesis. To complement these findings, here we report FT activity on the Sertoli cell (SC) surface. SC isolated and cultured from 20-day-old rat testes displayed FT activity with a Vmax of 12.5 pmoles/mg protein/min and a Km of 22 microM, while purified Sertoli cell plasma membranes (SCPM) showed FT activity with a Vmax of 10 pmoles/mg protein/min and a Km of 18.2 microM for GDP-[14C]-L-fucose. Fucosyltransferase activities were 16.7 and 2.6 pmoles/mg protein/min in SC and SCPM, respectively; approximately 16% of FT activity is, therefore, on the cell surface. To test whether the expression of FT activity in SC was regulated by hormones and growth factors, SC were cultured in serum-free medium supplemented with insulin, transferrin, sodium selenite, and epidermal growth factor (medium 4F) or in 4F plus follicle-stimulating hormone, testosterone, hydrocortisone, and vitamin E (medium 8F). We found that FT activity in SC is not modulated by these hormones or growth factors (4F or 8F). For comparison with FT, galactosyltransferase (GalTase) activities in SC and SCPM were also determined. SC displayed GalTase activity with a Vmax of 50 pmoles/mg protein/min and a Km of 38.5 microM, while SCPM showed GalTase activity with a Vmax of 25 pmoles/mg protein/min and a Km of 20.8 microM for UDP-[3H]-galactose. Galactosyl-transferase activities were 29.2 and 9.6 pmoles/mg protein/min in SC and SCPM, respectively. Therefore, approximately 33% of the total cell GalTase activity was detected on the surface membranes of rat Sertoli cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Serological and immunohistochemical studies on sialylated carbohydrate antigens in colorectal carcinoma

Sialylated carbohydrate antigens, such as CA19-9 (sialyl Lea), CA-50 (sialyl Le4), CSLEX1 (sialyl Lex) and SLX (sialyl Lex-i), were assayed in the same preoperative serum samples of 63 patients with colorectal cancer, and compared with CEA. In addition immunohistochemical expressions of sialyl Lea, sialyl lex and sialyl Lex-i antigens were studied in 62 colorectal carcinomas and 42 normal mucosal sites remote from the malignant lesion using monoclonal antibodies CSLEA1, CSLEX1 and FH-6, respectively, in order to elucidate their tumor-specificity and clinical usefulness as a tumor-associated antigen. Serologically, the percent positive rates of CA19-9, CA-50, CSLEX1, SLX and CEA were 30.2%, 17.7%, 23.8%, 16.1% and 44.4%, respectively. In dukes' A and B, these sialylated carbohydrate antigens, especially CSLEX1 and SLX, showed low positive rates, but the percent positive rates of CSLEX1 and SLX correlated with operative radicality. The positive spectrum of CSLEX1 differed from that of CA19-9 in sera, and CEA had no correlation with these two antigens. The immunohistochemical expression rates of sialyl Lea, sialyl Lex and sialyl Lex-i were 88.1%, 17.0% and 9.5% in normal mucosa, but were 77.8%, 90.5% and 71.4% in carcinoma, respectively. These data suggested that the type 2 chain antigens CSLEX1 and SLX, which have high tumor-specificity compared with CA19-9, may be useful in preoperative diagnosis for extension of carcinoma and operative radicality, although early diagnosis using these sialylated carbohydrate antigens may be difficult, while the combined use of CA19-9, CSLEX1 and CEA should make it possible to detect a wide range of colorectal cancer patients.

Neoplastic alteration of a membrane-associated sialidase of rat liver

Rat liver particulate fraction contains two types of membrane-associated and gangliosides-hydrolyzing sialidase, which have been shown to be identical to two membrane-associated sialidases of rat brain (I and II) chromatographically, immunologically and in substrate specificity. Chromatography on AH-Sepharose 4B of the membrane sialidases of rat primary hepatoma induced by 3'-methyl-4-dimethylaminoazobenzene (MeDAB) further revealed that hepatocarcinogenesis induces a marked decrease in sialidase II but no decrease in sialidase I. Using antisera against sialidases I and II of rat brain, immunoprecipitation studies of the solubilized particulate fractions of rat liver and MeDAB-hepatoma gave results similar to those obtained chromatographically. Using the same immunological technique, sialidase II but not sialidase I was found to be decreased in AH109 A hepatoma and in regenerating and fetal liver.

Cell-surface galactosyltransferase acts as a modulator of rat and human acinar cell proliferation

Several physiological parameters were examined for inducing acinar cell proliferation and corresponding increased expression of beta 1-4 galactosyltransferase. In this study, dietary changes causing acinar cell proliferation included the following: the introduction of animals to a liquid diet (causing gland atrophy) followed by re-introduction of solid chow, gustatory stimulation provided by the introduction of 0.5% citric acid to animal drinking water, and removal of the submandibular gland with subsequent reliance on the parotid gland for saliva protein and fluid. Alterations in growth factor levels were produced by injecting animals with a chronic (three-day) regimen of either nerve growth factor (NGF) or epidermal growth factor (EGF). In all cases of acinar cell proliferation in vivo, generated by the above treatments, cell-surface galactosyltransferase was detected along with the unique expression of a 4.5-kb proliferation-associated mRNA. Parotid gland proliferation could be blocked in all cases by the injection of the galactosyltransferase specific modifier protein, alpha-lactalbumin. Propranolol, a beta-adrenergic receptor antagonist, blocked proliferation in all cases except EGF treatment. EGF-induced proliferation could, however, be prevented if the animals were treated with monoclonal antibody to EGF receptor or with the galactosyltransferase modifier alpha-lactalbumin. As a comparison, human parotid tissue samples obtained from neoplastic pleomorphic adenomas, muco-epidermoid carcinoma, adenoid cystic carcinoma, and a bulimia patient were analyzed for galactosyltransferase expression by Northern blot of mRNA and plasma membrane isolation. Elevated levels of galactosyltransferase were found in all neoplastic tissue preparations as well as in the bulimia sample. Amylase synthesis was reduced in samples compared with surrounding normal tissue from the same patient. In vitro cell culturing of pleomorphic adenoma cells in the presence of galactosyltransferase modifier alpha-lactalbumin and substrate UDP-galactose inhibited proliferation in a dose-dependent fashion. Southern blot analysis of DNA from neoplastic parotid cells showed an alteration in chromosomal gene structure for the galactosyltransferase activator cDNA from the adenoid cystic carcinoma. These results for induced acinar cell proliferation as well as human neoplastic pathologies suggest a direct role for cell surface beta 1-4 galactosyltransferase in signaling growth. Furthermore, the proliferation-associated activity of galactosyltransferase suggests that it may be considered as a new type of cell growth regulator.

Sialyltransferase activity in plasma cells of multiple myeloma

A marked elevation of sialyltransferase activity (STA) was observed in a solid tumor of plasma cells, which had been removed from a patient with multiple myeloma (MM), as compared to normal lymphatic tissues. STA was also determined in mononuclear bone marrow cells of 10 patients with MM and found to be 12 times higher than that of bone marrow mononuclear cells from 5 patients with non-malignant disorders (with less than 1% plasma cells in the bone marrow aspirate). A significant correlation was found between STA and the number of plasma cells in the bone marrow aspirate.

Sialyltransferase activity and sialic acid levels in multiple myeloma and monoclonal gammopathy

A significant elevation of peripheral blood mononuclear cell sialyltransferase activity (STA) was observed in 14 patients with multiple myeloma (MM), and compared to 7 patients with monoclonal gammopathy of undetermined significance (MGUS) and to 10 controls. Serum sialyltransferase was significant higher in MM patients as compared to controls. It was also higher than in MGUS patients, but the difference here was not statistically significant. STA was also determined in mononuclear bone marrow cells of 5 patients with MM (with 50 to 100% plasma cells in the bone marrow aspirate) and found to be 19 times higher than that of bone marrow mononuclear cells from 6 patients with non-malignant disorders (with less than 1% plasma cells in the bone marrow aspirate). No significant differences were observed in peripheral blood mononuclear cell sialic acid levels between MM, MGUS and controls.

Phosphohexose isomerase in hypernephroma. Significance as serum tumor marker, comparison to other glycolytic enzymes and isozyme patterns in normal and tumor tissue

In hypernephroma an overall diagnostic sensitivity of 72% and a specificity of 87% was found for the serum tumor marker phosphohexose isomerase (PHI). Both in early stage disease and in well differentiated tumors a sensitivity of about 60% was reached. In contrast the sensitivity of three other glycolytic enzymes tested was found to be less than 20%. Since the cancer induced elevation of PHI activity in the tumor was found to be comparable to those of the other test enzymes, elevated PHI serum activities cannot be attributed to overproportional PHI synthesis and unspecific cell-lysis. In 6 of 10 cases studied differences in the PHI isozyme pattern between the tumor and the normal tissue were found suggesting the occurrence of cancer associated structural alterations of PHI.

Cell surface expression of 4 beta-galactosyltransferase accompanies rat parotid gland acinar cell transition to growth

Rat parotid gland acinar cells stimulated to divide by a chronic regimen of isoproterenol demonstrate a dramatic increase in the synthesis of the glycosyltransferase 4 beta-galactosyltransferase. A plasma membrane localization for much of the increase in 4 beta-galactosyltransferase was determined by density gradient membrane fractionation. Golgi-enriched fractions showed no increase in specific activity, while plasma membrane activity increased 40-fold. This selective increase at the cell surface was confirmed by immunofluorescence of intact, nonpermeabilized cells from treated glands, using a monospecific antibody prepared against the purified bovine milk transferase. In detergent-permeabilized cells staining of nontreated cells was seen only as groups of perinuclear vesicles, presumed to be Golgi apparatus. In isoproterenol-treated and permeabilized cells both presumptive Golgi and cell surface staining was apparent. Enzyme assays performed on intact cells established that the enzyme's active site was oriented to the exterior of the cells. The transferase could be detected as early as 3 hr after the primary challenge with isoproterenol. Pretreatment of rats with cycloheximide prevented its appearance.

Membrane-associated sialidase of rat liver and its decrease in hepatomas

Using the particulate fraction of tissue homogenate, plasma membrane-associated sialidase was assayed at pH 4.5 with bovine brain mixed gangliosides as the substrate. The activity was lower in rat hepatoma induced by 3'-methyl-4-dimethylaminoazobenzene (MeDAB) and transplantable AH-109A rat hepatoma than in normal rat liver. The enzyme was almost quantitatively solubilized from liver particulate fraction by using 0.5% (w/v) sodium deoxycholate plus 0.2% (w/v) Triton X-100. When chromatographed on DEAE-cellulose, the solubilized activity emerged as a single peak. The enzyme thus obtained was maximally active at pH 4.5, and readily hydrolyzed mixed gangliosides but was less active toward 4-methylumbelliferyl-alpha-N-acetylneuraminic acid, 3'-sialyllactose and fetuin. The corresponding enzyme from MeDAB-induced hepatoma was indistinguishable from the liver enzyme in terms of ease of solubilization, pH-activity relationship, chromatographic behavior and substrate preference. It therefore appears that the plasma membrane-associated sialidase of hepatomas differs from that of liver only in the tissue level of activity.

Expression of pancreatic secretory trypsin inhibitor gene in neoplastic tissues

Expression of the human pancreatic secretory trypsin inhibitor (PSTI) gene was examined in 24 cases of neoplastic tissues by Northern blot analyses. In three cases of lung adenocarcinoma and one case of sigmoid colon polyp, we detected transcripts which hybridized to the human PSTI cDNA probe. cDNA libraries were constructed using mRNAs of the two PSTI-positive tumor tissues. Two PSTI cDNA clones were obtained from each sample. Sequencing analyses showed that they were completely identical with that of pancreatic PSTI cDNA which had been reported [(1985) Biochem. Biophys. Res. Commun. 132, 605-612]. Southern blot analyses showed that the elevated expression of PSTI in neoplastic tissues was accompanied by neither PSTI gene amplification nor rearrangements.

The structural relationship of blood group-related oligosaccharides in human carcinoma to biological function: a perspective

Blood group-related oligosaccharides have been isolated from a limited number of carcinomas. The carcinoma-associated oligosaccharides show chain elongation, for example due to repeating Gal 1,4 GlcNAc 1,3 sequences, or a higher degree of branching, which permit increased sialylation and fucosylation. Abnormal carbohydrate structures have been demonstrated on tumor cell membranes by immunological techniques, which suggests deletion of ABH, accumulation of 'crypt' antigens such as I and T antigens, and abnormal expression of Lewis antigens. Changes in carcinoma-associated oligosaccharides can result from altered biosynthetic processing in the Golgi apparatus or the occurrence of abnormal tumor glycosyltransferase isoenzymes. Structural alterations of oligosaccharides on the tumor cell membrane are related to the regulation of tumor growth, cell-cell interaction, cell differentiation, and metastasis. Glycoproteins secreted by tumor cells into the circulation evoke cellular and humoral immunity and cause immune suppression by binding to cytotoxic T lymphocytes and lymphocyte subsets. The relationship of oligosaccharide structures to biologic function awaits elucidation.

Cell surface expression of 4 beta-galactosyltransferase accompanies rat parotid gland hypertrophy induced by changes in diet

Maintenance of rats for 2 weeks on a diet consisting of 50% inert cellulose and 50% laboratory chow resulted in hypertrophy of the parotid gland and a 4-fold increase in total membrane-associated 4 beta-galactosyltransferase enzyme activity (EC 2.4.1.38). Localization of the increased specific activity to the cell surface of the enlarged gland was shown by subcellular fractionation of Golgi and plasma membranes. This observation was confirmed by enzyme assays of intact cells; quantification of immunofluorescence was made by using a fluorescence activated cell sorter. Parotid gland hypertrophy was inhibited by the administration of the specific modifier protein alpha-lactalbumin as well as by a monospecific antibody for 4 beta-galactosyltransferase. These agents also inhibited the incorporation of thymidine into DNA.

Expression of a particular beta-N-acetylglucosaminidase isoenzyme in human haematopoietic leukemic cell-lines

N-acetyl-beta-D-glucosaminidase (NAG) activity and isoenzyme profiles were studied in myeloid, histiocytic, B-lymphoid, T-lymphoid and lymphoblastoid continuous cell lines in order to determine if N-acetyl-beta-D-glucosaminidase isoenzyme expression may help to distinguish among various types of leukemic proliferation. Total NAG activity in myeloid, histiocytic, erythroleukemic cell lines were higher than Burkitt's lymphoma derived cell lines (B-lymphoid), T- or lymphoblastoid cell lines. On chromatofocusing by PBE 94 coupled with an automated enzyme assay an intermediate (I) beta-N-acetyl-glucosaminidase form, eluting between forms B and A, was found in all leukemic and in Epstein-Barr virus infected lymphoblastoid cell lines analysed. The different profiles recorded, the expression of the I form and the different I/B ratios may be useful as markers of tumour proliferation.

Breast cancer markers: comparison between sialyltransferase and human mammary epithelial antigens (HME-Ags) for the detection of human breast tumors grafted in nude mice

Sialyltransferase (CMP-sialic acid:asialofetuin sialyltransferase) and human mammary epithelial antigens (HME-Ags, cell surface antigens specific to human mammary epithelial cells) were determined in plasma of nude mice grafted with breast and non-breast human tumors to assess their possible usefulness as breast cancer markers. The plasma transferase activity was significantly higher (p less than 0.01) in tumor groups relative to the control. However, no significant difference (p less than 0.05) could be found in the transferase level between breast and non-breast tumor groups, showing the enzyme's lack of specificity for breast cancer. Furthermore, the surgical procedure performed on the control normal healthy group (no tumor), resulted in an important increase of the enzyme level, while HME-Ags remained unchanged. HME-Ags were essentially negative in control as well as non-breast tumor groups. After surgical removal of breast tumors, HME-Ags level dropped drastically to the background level (from 122 to less than 30 ng/ml plasma). These data indicate that HME-Ags are more sensitive and specific than sialyltransferase as markers for human breast tumor, and suggest that HME-Ags may be clinically useful in the early detection of breast cancer as well as in the followup of patients with metastatic breast tumor.

Serum sialic acid in malignant tumors, bacterial infections, and chronic liver diseases

The total serum sialic acid concentration was determined in 2,264 persons with various malignant tumors, bacterial infections, rheumatic diseases, and chronic liver diseases, and in a control group. The thiobarbiturate method according to Warren was used. The upper limit (95% percentile) in the control group was 2.23 mumol/ml. Higher values were found in the groups with neoplasms (mean: 3.04 mumol/ml), inflammatory diseases (e.g., pneumonia: 3.02 mumol/ml), and active rheumatoid arthritis (3.05 mumol/ml). In the group with malignant diseases, the sialic acid concentration at the time of diagnosis was highest for bronchial carcinoma (3.29 mumol/ml) and lowest for breast cancer (2.58 mumol/ml). In chronic liver diseases the mean sialic acid level was lower than in a heterogeneous group of noninflammatory and nonneoplastic diseases. The estimation of the serum sialic acid concentration could be useful in the detection of tumor burden and metastases, and in the evaluation of the later course and prognosis of malignant neoplasms if bacterial/inflammatory and active rheumatoid processes can be excluded.

Galactosyltransferases: physical, chemical, and biological aspects

Galactosyltransferases (GTs) are one of the members of a family of enzymes called glycosyltransferases involved in the biosynthesis of complex carbohydrates. These enzymes catalyze the transfer of galactose from UDP-galactose to an acceptor (glycoprotein, glycolipid) containing terminal N-acetylglucosamine or N-acetylgalactosamine residue. GTs occur in soluble (milk, serum, effusions, etc.) and insoluble (membrane) forms. The GT activities on the outer surface of the cells have been correlated with a host of cellular interactions, including fertilization, cell migration, embryonic induction, chondrogenesis, contact inhibition of growth, cell adhesion, hemostasis, intestinal cell differentiation, and immune recognition. GTs have been purified to homogeneity using affinity chromatography. Most GTs are found active in the pH range 6 to 8 and at temperatures between 35 to 40 degrees C. Manganese is an essential co-factor for GT activity. Isoenzymes of GT have been recognized, especially in tumor tissues, malignant effusions, and sera of cancer patients using polyacrylamide gel electrophoresis in the presence and absence of SDS. Depending on the source of the enzyme, the molecular weights of GTs range between 40,000 to 80,000 daltons. Carcinoma-associated GT isoenzyme has been reported to have a higher molecular weight than the normal GT isoenzyme. Development of monoclonal antibody against the cancer-specific GT isoenzyme will provide help in the development of an immunoassay for the measurement of this isoenzyme in the sera and an aid in the radioimmunolocalization of the tumors in cancer patients.

Glycosidases in cancer and invasion

Glycosidases have been demonstrated to be elevated in the interstitial fluid of tumors, sera of animals and patients with tumors, and in some tumor tissue as compared to normal adjacent tissue. Elevations of serum beta-N-acetylglucosaminidase and beta-glucuronidase most commonly have been found to occur and these enzymes have been shown to be secreted into the extracellular medium by many different tumor cell types in vitro. The mechanism of cellular release of these hydrolytic enzymes probably involves tumor lysosomal exocytosis. Increased tumor glycosidase levels may promote increased tumor cell shedding from primary tumors, local invasion and perhaps be responsible directly, or indirectly for structural changes in tumor cell surface glycoconjugates. These cell surface changes could facilitate tumor cell thrombus formation, secondary site implantation and attachment in the microcirculation to endothelial cells and/or subendothelial basement membrane components. Other studies have demonstrated a correlation between metastatic cell potential and increased endoglycosidase and polysaccharide lyase activity. Generally, metastatic tumor cell variants have been found to be more invasive and capable of degrading proteoglycan basement membrane components, in part due to these increased levels of degradative enzymes. Hence, it is of considerable interest to develop inhibitors against these enzymes. Initial studies with glucuronidase inhibitors in the therapy of bladder tumors have been promising and with the advent of better agents and the use of appropriate in vitro metastatic models it may be possible to design and develop agents which interfere in various metastatic events and limit tumor progression.

Proteinases and sialyltransferase in human breast tumors

Proteolytic and sialyltransferase activities were determined in extracts of 65 human primary breast tumors, 6 lymph node metastases, 6 fibroadenomas and 27 normal tissues. Using proteins and synthetic selective substrates, we observed the presence of collagen-peptidases, plasminogen activator, cathepsin-B and cathepsin-D-like enzymes, and sialyltransferase. No active or trypsin-activatable type-IV collagenase activity was detected. Although individual variations between tumors were large, proteinase and sialyltransferase contents were significantly elevated in malignant breast tissues. Enzyme activities were found to be related to the epithelial volume of the tumor. No significant correlation was found between the proteinase or sialyltransferase activities and the degree of differentiation of the tumor cells, or the degree to which tumors had metastasized to regional lymph nodes. Since large variations of enzyme levels apparently reflect the heterogeneity of epithelial cell densities in tumor samples, proteolytic or sialyltransferase activities cannot therefore be used as a measure of quantitative evaluation of invasive properties in breast cancer.

The histochemistry of glycosidases in human benign and malignant breast tissue

Histochemical methods for the localization of four glycosidases (beta-glucuronidase, beta-N-acetyl glucosaminidase, beta-D-galactosidase and alpha-mannosidase) have been applied to 40 cases of human normal and hyperplastic breast tissue and 100 human breast carcinomas. All tissues have been fixed in formol-calcium at 4 degrees C and washed in gum sucrose. beta-Glucuronidase and beta-N-acetyl glucosaminidase have consistently been detected in essentially all cells of normal and hyperplastic tissue. A similar distribution has been found for better differentiated carcinomas but the number of cells with detectable enzyme decreases in the more poorly differentiated tumour. beta-D-Galactosidase and alpha-mannosidase have only been demonstrated in very occasional cells in normal breast tissue. The incidence increases in hyperplastic tissue, and in approximately half the carcinomas many cells have detectable enzyme. The localization of beta-D-galactosidase has not been related to tumour differentiation but the better differentiated carcinomas tend to have few cells with demonstrable alpha-mannosidase. Although it has been suggested that glycosidases can have an effect on membrane function no differences have been found between those carcinomas having a few or many cells with detectable enzyme and the presence or absence of axillary lymph node metastasis. Total enzyme activity cannot be detected in fixed tissue, nor can an accurate quantitative assessment be made, but under the conditions of this study it is possible to conclude that there are differences between normal and malignant breast tissue in the localization of glycosidases.

Sialyltransferase activity in tumor tissues

Sialyltransferase (ST) activity was examined in tumor and control tissues. Within each group of control tissues a wide variation in the levels of ST activity was observed. Only in 20% of the tumors was the ST activity above the range of enzyme activity of the corresponding group of control tissues. Compared with its corresponding normal counterpart from the same individual, ST was elevated in tumor tissue by a factor of 2.1 on average. The distribution function indicates an increase in enzyme activity in 74% of the tumors. Other tumor markers were also determined for comparison. The ratio of the lactate dehydrogenase (LDH) subunits (M/H) was increased in tumors by a factor of 1.3 on average; the frequency of increase was 75%. From the distribution function of our data it follows that a decrease in the ratio of the creatine kinase (CK) subunits (B/M) occurs in 56% of tumors, the average factor being 0.8. The Regan isoenzyme of the alkaline phosphatase (AP) could be demonstrated in 13% of the tumors. In serum and in tissues ST was found to be composed of multiple forms. However, an isoenzyme of higher tumor specificity has not yet been established.

Acid phosphatase in human breast cancer tissue

When the total acid phosphatase (AP) activity of mammary carcinoma was compared with those of benign pathology and normal mammary tissue the results showed statistically significant differences (P less than 0.05) when expressed per milligram of protein: 358 +/- 42 nmoles per hour (mean +/- standard error) in the malignant tumor, 216 +/- 30 in the benign pathology, and 96 +/- 45 in normal tissue and when expressed per milligram of DNA: 1858 +/- 234, 1227 +/- 140, 695 +/- 345 nmoles per hour, respectively. The polyacrylamide gel electrophoretic profiles showed different levels of isoenzymes 3 and 4 in the three tissue groups. The appearance of isoenzyme 1 is reported after treatment of the homogenates with 5% Triton X-100. It was also found by counterimmunoelectrophoresis that the 28,000 Xg mammary tumor supernatant cross reacts with an antiserum raised against AP isoenzyme 2 although the mammary tissue does not contain such an isoenzyme. To elucidate this point, isoenzymes 1, 3 and 4 were separated by columns of Sephadex G-200 and DEAE-Sephadex. By counterimmunoelectrophoresis, it was observed that only the fraction containing isoenzyme 4 cross-reacted with the antiserum anti-AP isoenzyme 2 maintaining the catalytic activity.

Collagenolytic mechanisms in tumor cell invasion

Connective tissue stroma and basement membrane structures probably present natural barriers to the migration of tumor cells. It has therefore been proposed that collagenolytic enzymes are required to facilitate the spread and invasion of tumor cells into host tissues. The collagenases and cathepsin B-like enzymes are thought to be involved, but the cellular source of collagenolytic activity at the tumor: host interface or 'invasion zone' remains obscure in most cases. The 'invasion zone' of different tumors is very variable with regard to the type and numbers of host or tumor cells, as well as the type of collagenous matrix, and few generalities can be made. The existence within a tumor of specialised subpopulations of cells which have different metastatic potential has been postulated. As a consequence it seems plausible that the phenotypic expression of highly invasive or metastatic tumor cells should include the potential for generating collagenolytic activity. Immunolocalisation studies have demonstrated the production of type I and type IV collagenases at sites of tumor invasion, but it does not appear to be a continuous process and only a small proportion of tumor and/or host cells elaborate enzyme at any one moment. Collagenase production is invariably microenvironmental in nature and it seems likely that local host:tumor cell interactions are important in modulating collagenolysis. Macrophages and mast cells have been shown to stimulate collagenase expression by tumor and stromal cells in vitro, and it is proposed that these cells may assume a contributory role for the induction of collagenolytic activity in vivo. The collagenolytic mechanisms that operate at micro-foci of host:tumor junctions probably depend upon the type of collagen, the cellular composition and the extracellular ionic conditions of each invasion site. Either tumor or host cells may elaborate enzymes, this being dependent upon the type and/or tissue location of the invasive tumor.

Cysteine proteinases and metastasis

Cysteine proteinases are a subclass of endopeptidases which require activation by thiol reagents. A tumor cysteine proteinase which appears to be related to lysosomal cathepsin B has been implicated in the ability of tumor cells to invade the extracellular matrix and to metastasize to secondary sites. Lysosomal cathepsin B can degrade such components of the extracellular matrix as collagen, fibronectin and proteoglycans. Activity of this cathepsin B-like cysteine proteinase (CB) has been correlated with tumor malignancy in a number of tumor lines yet not in all tumor lines studied. CB activity in tumors seems to be associated with the viable tumor cells, probably with the plasma membrane of these tumor cells. CB activity has been measured in the sera, urine, ascites fluid and pancreatic fluid of tumor-bearing patients. CB is released from tumor explants and tumor cells in vitro as well as from normal subcutaneous tissue exposed to tumor-conditioned medium. Cathepsin B from normal tissues is rapidly inactivated above pH 7.0. Therefore, CB in tumor cell membranes or released from tumor cells (or from host cells in response to tumor cells) may not possess proteolytic activity at neutral pH and thus may not facilitate tumor cell invasion. However, CB exhibits enhanced stability at neutral or slightly alkaline pH's. There is not yet definitive proof that CB plays a role in tumor invasion and metastasis. There is, however, an increasing body of correlative evidence relating CB activity and tumor malignancy. This correlative evidence plus preliminary evidence that tumor CB can degrade components of the extracellular matrix in vitro suggests that CB may be one proteinase active in a proteolytic cascade resulting in tumor invasion and metastasis.

Chromosome analysis of two rat tumor cell lines. Possible role of DMs and HSR in metastasis

The rat tumor cell lines BSp73AS (AS, non-metastasizing with pronounced adherent capacities) and BSp73ASML (ASML, highly metastasizing with reduced adherent capacities) were cytogenetically investigated. The ASML cell line is reportedly derived from the AS cell line. Both lines exhibited abnormal numerical and structural chromosomal characteristics. The metastasizing ASML cells showed a higher chromosome number (modal number: 62-63) than the nonmetastasizing AS cells (modal number:48). The AS karyotype was characterized by the presence of a large metacentric marker chromosome resulting from a Robertsonian translocation (Rb 6.7). This chromosome is as such absent in ASML cells but perhaps it may be present in these cells with a major part of chromosome 7 being deleted. The most interesting feature of the ASML karyotype was the presence of double minutes (DMs) and a homogeneously staining region (HSR) at the telomeric end of chromosome 6. These were peculiar to the ASML cells, being absent in the AS cells. DMs and HSR are reported to be correlated with the resistance to various drugs and with the acquired virulence of tumor cells through gene amplification. Therefore, we assume that in the metastasizing ASML cell line the DMs and HSR were established through genetic selection and that they are probably related to the acquired metastasizing capacity of these cells.

Increase in homotypic aggregation of metastatic Morris hepatoma cells after fusion with membranes from non-metastatic cells

Three types of Morris hepatoma: 7288C, 5123tc, and 9618A were assessed for their ability to grow and produce metastases in the lungs of male buffalo rats. Hepatoma 7288 formed metastatic growths more rapidly than 5123, while 9618 did not form metastatic growths in the lung at all. Cells from the same three hepatomas were then assessed for their ability to aggregate homotypically in vitro. This was used as a measure of potential for detachment from the site of primary growth in vivo, one of the critical steps in metastasis. The results were that 9618 aggregated more effectively than 5123 and 7288 did not aggregate homotypically. Thus, the ability to metastasize and the ability to aggregate homotypically were inversely related in these three tumors, with the most metastatic tumor, 7288, hardly aggregating at all. Was the ability of hepatoma 9618 to aggregate homotypically and the inability of hepatoma 7288 to do so a characteristic of the plasma membrane? Plasma membranes either from the tumor which aggregated best, 9618, or from the liver of non-tumorous neonatal buffalo rats were fused into the surface of the 7288 cells. Either fusion conferred the ability to aggregate on the previously non-aggregating metastatic hepatoma cells. In contrast, fusion of plasma membranes from hepatoma 7288 into 9618 cells failed to affect their ability to aggregate homotypically. The aggregation-conferring effect required actual fusion of the donor membrane, was dependent on the amount of membrane fused and was sensitive to treatment of the donor plasma membranes with trypsin. The results are interpreted as suggesting the presence of homotypic aggregation materials, probably proteins, in the plasma membranes of non-metastatic cells. These may be reduced or absent in the membrane of the highly metastatic hepatomas.

Serum sialyltransferase and fucosyltransferase activities in patients with bronchial carcinoma

Serum sialyltransferases and fucosyltransferases measured by an affinity adsorbent technique were studied in 27 exactly defined patients with malignant pulmonary diseases. Fourteen patients with benign pulmonary diseases and 56 with benign surgical diseases were used as controls. Enzyme activities were expressed as amounts of labeled precursor molecules incorporated into endogenous acceptors in counts per minute (cpm). The mean sialyltransferase activity was 583 cpm in bronchial carcinoma, 485 cpm in benign pulmonary disease and 428 cpm in benign surgical disease. The only statistically significant difference was between bronchial carcinoma and benign surgical disease. The mean fucosyltransferase activity was 813 cpm in bronchial carcinoma, 436 cpm in benign pulmonary disease and 255 cpm in benign surgical disease. All the differences were statistically significant. There were no statistically significant differences between the WHO histologic bronchial carcinoma groups. The correlation between sialyltransferase and fucosyltransferase activity in bronchial carcinoma was statistically significant (r = 0.59). In squamous cell carcinoma (N = 6), it was strongly significant (r = 0.96) and there was a significant correlation also in small cell carcinoma (N = 10; r = 0.79) but not in adenocarcinoma (N = 9; r = 0.30) and benign pulmonary disease (N = 14; r = 0.44). It is suggested that serum sialyltransferases and fucosyl transferases would not be decisive for diagnosis when used alone in bronchial carcinoma, but could be included in a screening test battery.

Post-operative serum sialyltransferase levels and prognosis in breast cancer

Serum sialyltransferase (SST) activity was measured 10 days after mastectomy in 153 patients with operable breast cancer. Enzyme activity declined with time in storage (1-42 months). After correction for loss of activity in storage, patients with SST activity below the median value had a longer disease-free interval (DFI) than those with SST activity above the median, and this difference remained when patients were stratified by axillary nodal status, tumor size, and tumor grade. Survival was longer in patients with low SST activity. Post-operative elevation of SST indicates a poor prognosis in patients with operable breast cancer.

Serum-sialyltransferase activity in cancer patients

Serum-sialyltransferase activity was measured in serum samples of 116 patients with malignant tumors of various origins and different clinical stages using asialo-fetuin as the acceptor and cytidine-5'-mono-phospho[14C]sialic acid as the donor. Only patients with metastatic tumors had significantly elevated serum-sialyltransferase levels. Increased enzyme activity was also associated with rheumatoid arthritis and with acute hepatitis, whereas no significant alteration of enzyme activity was observed in cystic fibrosis patients. In a group of tumor patients, various additional tumor markers were determined (carcinoembryonic antigen, alkaline phosphatase: Regan isoenzyme, creatinekinase: BB-isoenzyme, lactatedehydrogenase: isoenzyme 5) and the data compared to the clinical diagnoses. The sensitivity and specificity of serum-sialyltransferase as a tumor marker is assessed.

Usefulness of clinical chemistry measurements in classifying patients with breast cancer

Laboratory measurements can be used to detect, classify, and monitor patients with breast cancer. This review covers in detail the clinical usefulness of carcino embryonic antigen, tissue polypeptide antigen, various glycoproteins, pregnancy-associated proteins, casein, lactalbumin, beta-2-microglobulin, ferritin, immunoglobins, acute phase proteins, placental-like alkaline phosphatase, liver-associated enzymes, glycosyltransferases, human chorionic gonadotropin, calcitonin, polyamines, and collagen breakdown products, in relationship to their diagnostic utility in patients suspected of having or known to have breast cancer. In addition, these authors assess the merits of various multivariate techniques using a number of clinical chemistry quantities in the same regard. Finally, the relative contribution of biochemical tests vs. the information values gained from "surgical pathology" data (number of positive nodes, number of negative nodes, and degree of anaplasia) is discussed.

Beta-hexosaminidase activities and isoenzymes in normal human ovary and ovarian adenocarcinoma

Levels and isoenzyme profiles of beta-hexosaminidase were compared in extracts from normal ovarian and ovarian epithelial tumors. The specific activities of beta-hexosaminidase were significantly (P less than 0.001) higher in malignant than in normal ovarian tissues. The enzyme levels of the tumors depended on their degree of differentiation. Well-differentiated tumors had activities in the normal range, while poorly differentiated ones had values higher than the normal mean +/- 2 SD. The moderately and moderately to poorly differentiated tumors had intermediate levels. DEAE-cellulose chromatography was used to resolve the isoenzyme of beta-hexosaminidase. Two major forms, beta-hexosaminidase A and beta-hexosaminidase B, were detected in all the preparations. In one tumor specimen, a component eluting slightly ahead of beta-hexosaminidase A was also detected. For quick separation, a batch-wise procedure using DEAE-cellulose was adapted. Proportions of the isoenzymes A and B separated by batch-wise procedure were similar to those obtained by column chromatography. Heat stability, optimum pH, acid stability and substrate specificity of the beta-hexomsaminidase isoenzymes from ovarian tissues were similar to those from other human sources. Isoenzymes from tumor extracts were more labile to heat and acid pH compared with those from normal source. Slight differences in the affinity for the substrate p-nitrophenyl-beta-N-acetyl-galactosaminidase between the isoenzymes from normal and malignant ovaries were noted.

Human mammary epithelial antigens (HME-Ags) in the circulation of nude mice implanted with a breast tumor and non-breast tumors

Human mammary epithelial antigens (HME-Ags) obtained from the membrane of the human milk fat globule (HMFG) were tested for their possible role as breast tumor markers. Specific antisera raised against HME-Ags were used to monitor plasma concentrations of these antigens in nude mice implanted with a human breast tumor. The level of plasma HME-Ags, determined by radioimmunoassay, was significantly higher in animals transplanted with a human breast tumor (mean +/- standard error; 687 +/- 184 ng/ml) than those with other types of human tumors (colon carcinoma: 50 +/- 29; lung carcinoma: 82 +/- 78; medulloblastoma: less than 30; and Wilson melanoma: less than 30) and healthy control animals (49 +/- 22). Removal of the breast tumor resulted in a significant drop of HME-Ags level to "background" values, suggesting that animals with the breast tumor did release into the circulation HME-Ags which could be possibly used as breast-tumor markers in breast tumor diagnosis.

Partial characterization of sialoglycopeptides produced by cultured human melanoma cells and melanocytes

The sialoglycopeptides produced by HM7 human melanoma and fetal uveal melanocyte cultures grown in the presence of [3H]glucosamine and [35S]sulfate were isolated from the Pronase digests of cells, spent media, and intracellular material. From the melanoma culture, six sialoglycopeptides, accounting for 43% of the total 3H radioactivity in the nondiffusible cell-associated glycopeptides, were purified. A major glycopeptide (GPIb) having an apparent molecular weight in the range 12 000-15 000 showed specific sialic acid dependent to interaction with wheat germ agglutinin (WGA). It was found to contain mainly O-glycosidically linked oligosaccharides having the structure (AcNeu) leads to 0-2[Gal leads to GalNAc]; some N-glycosidically linked saccharides were also present. A second WGA-binding glycopeptide (GPIa) was smaller and less anionic and had a higher proportion of N-glycosidically linked saccharides than GPIb. The normal fetal cultures yielded either no (iris) or markedly reduced (melanocytes) quantities of the WGA-binding glycopeptides. The four WGA-nonbinding sialoglycopeotides purified from melanoma were shown to have complex (N-acetyllactosaminly type) oligosaccharides linked via N-acetylglucosamine to asparagine with either no or insignificant amounts of O-glycosidically linked saccharides. The corresponding glycopeptides from melanocytes were of smaller molecular size and lower anionic charge, reflecting an overall lower degree of glycosylation.

Metastatic potential is positively correlated with cell surface sialylation of cultured murine tumor cell lines

The ability of murine tumor cells to metastasize spontaneously from subcutaneous sites is positively correlated with the total sialic acid content of the cells in culture, the degree to which the sialic acid is exposed on the tumor cell surface, and, most strongly, with the degree of sialylation of galactosyl and N-acetylgalactosaminyl residues in cell surface glycoconjugates. These findings suggest that sialic acid on the cell surface may play a role in tumor cell metastasis.

Arylsulfatases of human-lung tumors transplanted into athymic mice. Cancer-associated modification of arylsulfatase B variant

The activities and properties of arylsulfatase A and B from human lung carcinoma transplanted into athymic mice were demonstrated. The activities of arylsulfatase A and B from transplanted carcinomas with four histological types were more than twofold higher as compared to those from surgical tumors, except for arylsulfatase A activity in blastoma. Arylsulfatase B in transplanted tumors was almost completely replaced, except for blastoma, by an anionic B variant (B1) which was a minor component of arylsulfatase B in surgical lung tumor and absent in normal human lung. The properties of arylsulfatases A and B from transplanted tumors were essentially identical, respectively, with those from normal lung or surgical tumors in respect of molecular weight, heat stability, pH optimum, isoelectric point (pI), Km, time course profile and substrate specificity. Arylsulfatase B1 showed the properties similar to B enzyme except for net charge. The cause of the negative charge of tumor B1 enzyme was investigated. By the action of phosphatase, which was added exogenously or had been persistently included in the partially purified enzyme preparation, B1 enzyme (pI 7.5) shifted to about pI 8.2. Treatment of B1 enzyme with neuraminidase, concomitant with the endogenous phosphatase, resulted in marked increase (pI 9.5) of the isoelectric point, identical to that of arylsulfatase B. Thus, it is most probable that tumor B1 enzyme is modified by additional sialic acid and phosphate bound to arylsulfate B.

Characterization of an unusual isoenzyme of N-acetyl-beta-D-hexosaminidase from a human colonic carcinoma cell line

A sub-line with increased metastatic ability was previously isolated from an established human colonic carcinoma cell line [Kimball & Brattain (1980) Cancer Res. 40, 1574-1579]. The separation and characterization of the isoenzymes of N-acetyl-beta-D-hexosaminidase from each cell line are reported. The parental cell line contained A and B isoenzymes. The sub-line lacked the A-isoenzyme activity and contained an atypical B isoenzyme that was thermolabile, susceptible to alkylation and of lower molecular weight.

The synthesis of a proteinase inhibitor, alpha-1-antichymotrypsin, by human breast epithelial cells

The synthesis and release of glycoproteins were studied in organ cultures of human breast surgical specimens and in established breast epithelial cell lines, MCF-7 and MDA-MB-231. Biosynthesis was monitored by the incorporation of 14C-glucosamine. Labeled macromolecules in the culture supernatants were analyzed by biochemical and immunological techniques. One to 8% of the labeled glycoproteins from benign breast and infiltrating ductal carcinoma specimens was precipitated by antibodies produced against human serum alpha-1-antichymotrypsin. Twelve percent of the total glycoproteins from the culture supernatants of the MCF-7 cell line was identified as alpha-1-antichymotrypsin. Both the normal serum and the human breast epithelia-derived proteinase inhibitor can be resolved into similar subclasses by two-dimensional gel electrophoresis. MDA-MD-231 and MCF-7 cells which were extensively washed with EDTA, serum-free medium, and phosphate-buffered saline retain this proteinase inhibitor on their cell surfaces. Three to 4% of the total cell-surface iodinated components was immunoprecipitated by these specific antibodies. Since alpha-1-antichymotrypsin is a potent inhibitor of neutral proteinases such as cathepsin G, the demonstration of its synthesis by benign and malignant breast epithelial cells is of considerable interest. This glycoprotein may represent the epithelia's own protective shield of cell surface components and the cell's attempt to moderate the effects of invading leukocytes. In addition, it may play a regulatory role in the maintenance of three-dimensional glandular structures.

Serum levels of glycosyltransferases and related glycoproteins as indicators of cancer: biological and clinical implications

Many studies have suggested that malignant transformation is associated with fundamental changes in the cell surface; similar changes have been described for normal stem cells and cells of embryonic or fetal origin. There is now evidence that the tumor cell secretes or sheds glycoproteins and glycosyltransferases into the surrounding medium and into serum. There are claims that some of these serum glycoproteins and glycosyltransferases are associated with, or specifically related to, the extent of tumor growth and may serve as a cancer marker. A cancer-associated galactosyltransferase isoenzyme (GT-II) has been described and purified. Different isoelectric forms of fucosyltransferase have also been described as indicative of malignancy. The articles to be published in CRC Critical Reviews in Clinical Laboratory Sciences will analyze the evidence for the association of these membrane factors with tumor growth. In order to better understand the possible significance of altered glycoproteins and of increased or different forms of glycosyltransferases during tumor growth, recent data on glycoprotein synthesis will be discussed including the new concepts on the control of glycoprotein synthesis through lipid intermediates. The possible mechanisms whereby malignant transformation could alter glycoprotein synthesis will be discussed with particular emphasis on the significance of these alterations to the biology of the malignant cell. Changes in surface membrane glycoproteins have long been implicated in the ability of a cell to metastasize. Secretion and/or shedding of the cell surface may also be important in the process of metastasis and in altering the host immune response. Detection and the study of these "shed" materials in patients appear to be indicating a new approach to cancer biology detection and therapy.

Present and future trends in selected areas of clinical enzymology

Recently developed enzyme tests that are used in (a) identifying high risk populations, (b) diagnosing cancer, (c) following treatment response of cancer patients, and (d) the selection of cancer therapy are summarized. The diagnostic role of methionine adenosyltransferase and CSF monoamine oxidase activity measurements in the diagnosis of schizophrenia are discussed. The role of N-acetyltransferase in the conversion of serotonin to melatonin in the pineal gland and the importance of these changes for the synchronization of the functioning of cells throughout the organism are described. New developments in the determination of immunoreactive trypsin in the early diagnosis of pancreatic diseases are summarized.

Elevated glycosyltransferase activities in infected or traumatized hosts: nonspecific response to inflammation

Streptococcus pneumoniae infection leads to multifold increases in sialyltransferase, galactosyltransferase, alpha 2-fucosyltransferase, and alpha 3-fucosyltransferase activity of rat liver. Such changes may reflect an increased demand for glycosylation of acute-phase proteins synthesized and secreted by the liver during inflammatory processes. Serum sialyltransferase became elevated in bacteria-infected or burned rats and sandfly fever-infected humans, but did not correlate with acute-phase serum protein changes. These data suggest that nonparenchymal liver cells, such as macrophages, may contribute substantially to elevated sialyltransferase activity in the circulation during infection and, as such, represent a general host response to infection and tissue trauma.

Pancreatic elastase and serum alpha 1-antitrypsin levels in beagle dogs smoking high- and low-nicotine cigarettes: possible mechanism of pancreatic cancer in cigarette smokers

Beagle dogs exposed to cigarette smoke for 600 d experience a significant change in pancreatic elastase levels, as measured in tissue homogenates, compared with their sham-exposed controls. Greater elastase activity was found in the high-nicotine cigarette smokers than in the low-nicotine cigarette smokers. Levels of serum alpha 1-antitrypsin, an antiprotease capable of complexing the excess elastase, were also investigated. Animals smoking high-nicotine cigarettes had significantly lower serum alpha 1-antitrypsin activities than controls. Low-nicotine smokers showed alpha 1-antitrypsin activities that were not significantly different from those of controls. The importance of these observations is reinforced by a number of studies suggesting that proteases, their inhibitors, and an imbalance thereof may be related to the onset of neoplastic lesions. Studies have indicated that antiprotease levels follow the patterns of Mendelian inheritance. Severe deficiency states predispose human subjects to emphysema. A similar relationship may exist between antiprotease levels and susceptibility or resistance to neoplasms of the pancreas, a concept that deserves investigation in light of the findings reported here.