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R J Bernacki

Publications and source records attributed to R J Bernacki.

At least 55 records · Page 3Linked to original sources
PubMed1990

Fluorinated carbohydrates as potential plasma membrane modifiers. Synthesis of 4- and 6-fluoro derivatives of 2-acetamido-2-deoxy-D-hexopyranoses.

2-Amino-2,4-dideoxy-4-fluoro- and 2-amino-2,4,6-trideoxy-4, 6-difluoro-D-galactose, and 2-amino-2,4-dideoxy-4-fluoro- and 2-amino-4-deoxy-4, 4-difluoro-D-xylo-hexose were synthesized, as potential modifiers of tumor cell-surface glyco-conjugate, from benzyl 2-acetamido-3-O-benzyl-2-deoxy-4, 6-di-O-mesyl-alpha-D-glucopyranoside and benzyl 2-acetamido-3, 6-di-O-benzyl-2-deoxy-4-O-mesyl-alpha-D-glucopyranoside, which were converted into the corresponding 4,6-difluoro-2,4, 6-trideoxy and 2,4-dideoxy-4-fluoro derivatives. Benzyl 2-acetamido-2-deoxy-4-O-mesyl-alpha-D-galactopyranoside and benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-alpha-D-xylo-hexo-4-ulopyra noside were treated with diethylaminosulfur trifluoride to give 2-amino-2,4-dideoxy-4-fluoro-D-glucose and 2-amino-2,4-dideoxy-4, 4-di-fluoro-D-xylo-hexose derivatives, respectively, to give after deprotection the target compounds. Several of the peracetylated sugar derivatives inhibited L1210 tumor-cell growth in vitro at concentrations of 1-5 10(-5) M. The peracetylated derivative of 2-amino-2,4-dideoxy-4-fluoro-D-galactose inhibited protein and glycoconjugate biosynthesis, and also exhibited antitumor activity in mice with L1210 leukemia.

Acetylgalactosamine↗
PubMed1990

Role of galaptin in ovarian carcinoma adhesion to extracellular matrix in vitro.

Immunohistochemical studies indicated that galaptin is a major protein of ovarian carcinoma cells present in patient effusions and it is distributed throughout the cytoplasm. Enzyme-linked immunoadsorbent assay (ELISA) and immunoprecipitation experiments demonstrated that galaptin is also a major protein of the A121 ovarian carcinoma cell line, constituting less than or equal to 1% of extractable protein bound by DEAE Sephacel. Western blot analyses revealed that the galaptin present in ovarian carcinoma consists of a 14.5 KD subunit. Ovarian carcinoma and mesothelial cells isolated from patient effusions display surface receptors for galaptin with an apparently greater density of receptors present on the carcinoma cells. A121 cells also display surface receptors for galaptin: binding sites/cell = 3 X 10(8) and Ka = 1.2 X 10(9) M-1. The presence of galaptin in bovine corneal endothelial cells (BCEC) and BCEC-derived extracellular matrix (ECM) was demonstrated by ELISA. Of the total ECM-bound galaptin, about 75% appears to be insoluble in phosphate-buffered saline (PBS) lactose. ECM was also found to contain abudnant receptors for galaptin. Treatment of ECM with lactose increased the apparent galaptin receptor density:binding sites/cm2 = 7 X 10(13) and Ka = 2.6 X 10(9) M-1. Pretreatment of A121 cells with galaptin inhibited adhesion to ECM. The addition of exogenous galaptin to ECM had variable effect on cell adhesion. The data presented here suggest that early adhesion events may be carbohydrate-specific involving interaction between ECM-bound galaptin and cell surface galaptin receptors.

Animals↗
PubMed1990

Antitumor properties of tetrahydrobenz[a]anthraquinone derivatives.

The compound 8,11-bis[[2-[(2-hydroxyethyl)amino]ethyl]amino]- 6-methoxy-1,2,3,4-tetrahydro-7,12-benz[a]-anthraquinone (7) was synthesized from 3,6-dimethoxyphthalic anhydride and 6-methoxy-1,2,3,4-tetrahydronaphthalene by a Friedel-Crafts reaction, cyclization to form a dihydroxyanthraquinone, and conversion into the amino-substituted derivative by reaction with 2-[(2-hydroxyethyl)amino]ethylamine. The new compound, a ring D analogue of mitoxantrone, showed growth inhibition, at micromolar concentrations, of murine leukemia 1210, human lung H125, human breast MCF7, human ovary 121, and human colon WiDr and increased the life span of leukemic mice by 38%.

Animals↗
PubMed1989

Human ovarian carcinoma beta-N-acetylglucosaminidase isoenzymes and their role in extracellular matrix degradation.

Degradation and invasion of basement membrane by tumor cells involves the cooperative hydrolysis of proteoglycans, collagens, and glycoproteins mediated by a number of enzymes including proteases, collagenases, and glycosidases. In order to study these processes in vitro, a tissue culture system was developed in which bovine corneal endothelial cell extracellular matrix (ECM) serves as a substrate for attachment and degradation by human ovarian carcinoma cells. Using this system, a correlation was observed between solubilization of glycoconjugates present in ECM and extracellular levels of beta-N-acetylglucosaminidase (EC 3.2.1.30). To determine the role of individual isoenzymes of beta-N-acetylglucosaminidase (beta-NAG) in ECM degradation, the cellular and secreted forms of the enzyme were fractionated and characterized. Three intracellular isoenzyme forms A, I, and B, were isolated from invasive human ovarian carcinoma cell line A-121. In cell homogenate, forms A and B corresponded to 65 and 33% of total beta-NAG activity, respectively. Form I was found to be localized in the plasma membrane fraction of these cells. Two secreted forms of beta-NAG (As and Bs) were detected in serum-free medium. The separated intracellular and secreted isoenzymes demonstrated similar Km values, ranging from 1 to 5 mM, with p-nitro-B-N-acetylglucosaminide substrate. Treatment of [3H]glucosamine-labeled ECM with the separated isoenzymes of beta-NAG resulted in time- and concentration-dependent releases of radioactivity with potency of 1 greater than B much greater than A. These results suggest that human ovarian carcinoma cell beta-N-acetylglucosaminidase isoenzymes (forms B and A) contribute to ECM degradation as secreted enzymes and form I as a membrane enzyme.

Acetylglucosaminidase↗
PubMed1989

Characterization of human ovarian and endometrial carcinoma cell lines established on extracellular matrix.

Six cell lines were established from four patients with advanced carcinoma of the ovary and from one patient with carcinoma of the endometrium. These lines were established from fresh tumor material maintained initially on culture dishes coated with an extracellular matrix (ECM) produced by bovine corneal endothelial cells. Two of the six lines continue to require ECM as a substrate for optimal growth while the remaining four lines will proliferate on ECM or plastic substrate. Four cell lines transplanted into athymic nude mice were tumorigenic and maintained histologic and karyotypic similarities between the patient's original tumor, the cell line, and the transplantable tumor. Furthermore, in vitro degradation of ECM was grossly apparent by those cell lines which formed nude mice xenografts. Tumor cells were characterized by cytology, transmission electron microscopy, karyology, substrate requirements, steroid binding protein analysis, and morphological appearance in culture.

Animals↗
PubMed1989

2'-Fluorinated isonucleosides. 1. Synthesis and biological activity of some methyl 2'-deoxy-2'-fluoro-2'-pyrimidinyl-D-arabinopyranosides.

New reactions of methyl 2,2-difluoro glycosides are described that were utilized for synthesis of some novel nucleoside derivatives. Thus, treatment of methyl 2-deoxy-2,2-difluoro-3,4-O-isopropylidene-alpha (beta)-D-erythro-pyranoside (2) with anhydrous HCl resulted in selective displacement of one fluorine atom with chlorine to give a 2-deoxy-2-chloro-2-fluoro glycoside 3. Reaction of 3 with silylated uracil in the presence of SnCl4 provided a 2-deoxy-2-fluoro-2-uracil-substituted glycoside 4. 2-Fluoro-2-deoxy glycosides substituted with other pyrimidines at C-2 were prepared similarly by the reaction of acylated 2,2-difluoro or 2-fluoro-2-bromo derivatives (5 and 6, respectively) with silylated pyrimidines. The resulting 2'-fluorinated isonucleosides were evaluated for their antitumor and antiviral activities. Compounds 7a,b, 8a,b, and 10a,b demonstrated 50% tumor cell growth inhibition in vitro (IC50) at 10(-4)-10(-5) M. At similar concentrations no antiviral activity was observed in vitro. Therapeutic activity was obtained with 7a,b and 8a,b in DBA/2 mice with L1210 leukemia. Administration of 7a,b at 500 mg/kg, ip daily, for 5 consecutive days, resulted in a 55% increase in life span (% ILS) while administration of 8a,b in the same manner at 200 mg/kg caused a 29% ILS. Treatment with 7a,b to mice with drug-resistant L1210 sublines (5-FU and araC) resulted in 22 and 57% increases in life span, respectively. Lewis lung carcinoma and M5076 sarcoma in mice also responded to the administration of 7a,b with reductions in tumor growth for both tumors and significant increases in life span in mice with Lewis lung carcinoma. Although the mechanism of action of 7a,b is not known, it has been found to be a relatively fast-acting, cell-cycle nonspecific cytotoxic agent that decreases [3H]deoxyuridine incorporation, blocks L1210 cells at the G2 phase of the cell cycle, and is not reversed by exogenous thymidine. These 2'-fluorinated isonucleosides have demonstrated biological activity and may have potential as antitumor drugs.

Animals↗
PubMed1987

Role of glycosidases in human ovarian carcinoma cell mediated degradation of subendothelial extracellular matrix.

Penetration of the extracellular matrix (ECM) by tumor cells, an event which occurs at various stages of the metastatic process, involves tumor cell glycosidase mediated hydrolysis of proteoglycans (PG). Recently, we observed that human ovarian carcinoma cell lines (HOCC) derived from primary tumors, peritoneal effusions, and distant metastases possess a varying ability to degrade radiolabeled PG of the ECM, while normal cells (human mesothelial cells or ovarian fibroblasts) fail to do so. To determine whether a quantitative relationship exists between glycosidase activity and degradation of ECM, both intracellular and extracellular glycosidase activities were measured for HOCC and normal cell lines. No relationship was found between intracellular glycosidase activities and the ability of cells to degrade ECM. However, a correlation was observed between extracellular or secretory glycosidase activities and HOCC mediated ECM degradation. In particular, a 5-8-fold increase, as compared to normal cells, was observed for HOCC extracellular beta-N-acetylglucosaminidase (EC 3.2.2.30) activity. The accumulation or secretion of this enzyme from HOCC into culture medium was found to be time dependent and not related to intracellular levels. Purified hexosaminidase derived from invasive HOCC was able to hydrolyze [3H]-glucosamine radiolabeled ECM (up to 30% radiolabel) and resulted in the cumulative release of free [3H]-N-acetylglucosamine. This enzyme mediated hydrolysis could be completely prevented with 2-acetamido-2-deoxy-1,5-D-gluconolactone, a competitive inhibitor (Ki 10(-6) M). Finally, HOCC mediated degradation of radiolabeled ECM was discerned to be dependent upon active hexosaminidase action, since tumor cell mediated degradation of ECM could be inhibited by up to 60% in the presence of this synthetic competitive inhibitor. In summary, these studies indicate a strong association between HOCC solubilization of glycoconjugates present in the ECM and extracellular levels of hexosaminidase.

Acetylglucosamine↗
PubMed1987

Combinations of mesna with cyclophosphamide or adriamycin in the treatment of mice with tumors.

Following therapeutic administration, cyclophosphamide and Adriamycin are biotransformed to reactive metabolites, some of which are responsible for undesirable systemic toxicities of these chemicals, whereas others are responsible for their chemotherapeutic effectiveness. Microsomal mixed function oxidases activate cyclophosphamide to produce phosphoramide mustard and acrolein, while cytochrome reductase and xanthine oxidase are capable of transforming Adriamycin and forming free radicals. These reactive metabolites produce unwanted toxic side effects; however, their action may be partially ameliorated by the concomitant administration of thiols. In this study we evaluated the therapeutic activity of combinations of mesna (2-mercaptoethanesulfonate) with cyclophosphamide or Adriamycin in mice with a variety of transplantable tumors (L1210 and P-388 leukemia, Lewis lung and colon 26 carcinoma, B16 melanoma, and M5076 sarcoma). In all cases the administration of mesna prior to cyclophosphamide or Adriamycin treatment did not reduce the antitumor effectiveness of these agents and in some instances (C57BL/6 mice with B16 melanoma or M5076 sarcoma) small improvements were observed. Therefore, the addition of thiols, to reduce effectively the buildup of toxic metabolites of cyclophosphamide or Adriamycin may result in the improved therapeutic effectiveness for these agents in the treatment of cancer.

Animals↗
PubMed1987

Synthesis of glycopyranosylphosphonate analogues of certain natural nucleoside diphosphate sugars as potential inhibitors of glycosyltransferases.

The synthesis of alpha-D-glucopyranosyl-, alpha-D-galactopyranosyl-, and alpha-D-mannopyranosylphosphonate is described. Condensation of tris(trimethylsilyl) phosphite with 2,3,4,6-tetrakis-O-(phenylmethyl)-1-O-acetyl-alpha-D-glucopyranose generated 2,3,4,6-tetrakis-O-(phenylmethyl)-alpha-D-glucopyranosylphosphonic acetic anhydride (13). The benzyl blocking groups were removed by catalytic hydrogenation, and the anhydride bond was cleaved by alkaline hydrolysis to obtain alpha-D-glucopyranosylphosphonate (15). alpha-D-Galactopyranosylphosphonate (17) and alpha-D-mannopyranosylphosphonate (19) were also similarly synthesized. The anomeric configuration of 15 was assigned by single-crystal X-ray analysis, and the structural assignments of 17 and 19 were made on the basis of comparative NMR spectral studies. Compound 15 was then coupled with adenosine 5'-phosphoric di-n-butylphosphinothioic anhydride in dry pyridine to give adenosine 5'-phosphoric alpha-D-glucopyranosylphosphonic anhydride (23). Similarly, uridine 5'-phosphoric alpha-D-galactopyranosylphosphonic anhydride (24) and guanosine 5'-phosphoric alpha-D-mannopyranosylphosphonic anhydride (25) were synthesized from 17 and 19, respectively. With ovalbumin as an acceptor for [3H]galactose, provided by UDP-[3H]galactose, only uridine 5'-phosphoric alpha-D-galactopyranosylphosphonic anhydride (24) was shown to inhibit glycoprotein beta-D-galactosyltransferase (EC 2.4.1.38), with an apparent Ki equal to 165 microM. Even though these ionic compounds hardly penetrate the cell membrane, preliminary in vitro antitumor screening shows that compounds 23 and 25 are slightly active against human B-lymphoblastic leukemia and human T-lymphoblastic leukemia. None of these compounds show any antiviral activity.

Animals↗
PubMed1987

Synthesis of certain nucleoside methylenediphosphonate sugars as potential inhibitors of glycosyltransferases.

The synthesis of alpha-D-glucopyranosyl 1-(methylenediphosphonate) (11), alpha-D-galactopyranosyl 1-(methylenediphosphonate) (14), and alpha-D-mannopyranosyl 1-(methylenediphosphonate) (17) has been accomplished. [(Di-phenoxyphosphinyl)methyl]phosphonic acid (diphenyl-MDP) (5), synthesized by two different procedures, was fused with beta-D-glucopyranose pentaacetate followed by catalytic hydrogenation to give 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl methylenediphosphonate (glucose-MDP) (10). The anomeric configuration of 10 was assigned on the basis of NMR spectral studies. Condensation of 10 with 2',3'-di-O-acetyladenosine was accomplished by using 1-(mesitylene-2-sulfonyl)-3-nitro-1,2,4-triazole (MSNT) as coupling agent, and removal of the blocking groups gave adenosine 5'-[(alpha-D-glucopyranosylhydroxyphosphinyl)methyl]phosphonate (20). Uridine 5'-[(alpha-D-galactopyranosylhydroxyphosphinyl)methyl] phosphonate (23) and guanosine 5'-[(alpha-D-mannopyranosylhydroxyphosphinyl)methyl]phosphonate (26) were similarly prepared. Using a specific glycoprotein galactosyltransferase (EC 2.4.1.38) assay, uridine 5'-[(alpha-D-galactopyranosylhydroxyphosphinyl)methyl]phosphonate (23) demonstrated competitive inhibition with an apparent Ki of 97 microM. The adenosine analogue did not inhibit the enzyme. None of the above compounds show any in vitro antitumor or antiviral activity. Such specific inhibitors of glycosyltransferases may serve as specific probes to study various glycosyltransferases that might be involved in the process of metastasis.

Animals↗
PubMed1987

Insulin-modulated interleukin-2 production by murine splenocytes and a T-cell hybridoma.

Murine interleukin-2 (IL-2)-producing AOFS 21 T-cell hybridoma cells and normal murine splenocytes were stimulated in serum-free media by 16 potential mitogens/growth factors. Only insulin, concanavalin A (Con A), peptidoglycan monomer and a tumour-derived insulinoid stimulated [3H]thymidine incorporation by AOFS 21 cells and splenocytes. Supernatants of these stimulated cultures were tested for IL-2 activity which generally followed the pattern of growth stimulation. Both the mitogenicity and stimulation of IL-2 secretion by insulin were second only to the effects of Con A.

Animals↗
PubMed1986

Growth of human urologic tumors on extracellular matrix.

Surgical specimens of fifty urologic tumors, 19 renal, 19 bladder, nine prostate and three testicular, were disaggregated into a cell suspension by a two step mechanical and enzymatic method. Viability, cytology and flow cytometry (FCM) for DNA ploidy were subsequently determined. Growth of urological tumors on extracellular matrix (ECM) was carried out as follows: 2.5 to 5 X 10(5) cells were placed in plastic T25 flasks in RPMI 1640 + 10 per cent fetal bovine serum (FBS). 1.0 to 5 X 10(4) cells were plated in wells coated with ECM derived from bovine corneal endothelial cells with RPMI 1640 + 10 per cent FBS. Cultures were incubated for seven to 10 days at 37 degrees C. Only one (renal) out of 28 tumors grew on plastic. Forty out of 50 tumors (80 per cent) established primary cultures on ECM as determined by cell counting, protein determination, and/or [3H]thymidine incorporation. Previous experience with 106 urologic tumors grown on double layer agar demonstrated an overall success rate of 48 per cent. On ECM renal tumors showed 95 per cent growth success, prostate 89 per cent, bladder 63 per cent and testicular 67 per cent. Unlike viability by trypan blue exclusion, tumor DNA ploidy and percentage of malignant cells plated on ECM had no effect on growth success. The malignant nature of the cultured cells was confirmed by cytology. Twelve high grade and metastatic tumors caused degradation of the ECM. DNA ploidy was similar in four and different in six tumors before and after culture. Five tumors underwent in vitro drug testing on ECM with significant growth inhibition observed in three cases. The extracellular matrix seems to be a promising model for growing urologic tumors with excellent potential for drug testing in vitro.

Antineoplastic Agents↗
PubMed1986

Adhesion, growth and morphology of human mesothelial cells on extracellular matrix.

Human mesothelial cells (HMC) cover a variety of serosal surfaces and have been shown to rest upon an underlying subcellular basement membrane in vivo. Bovine corneal endothelial cells produce an extracellular matrix (ECM) in vitro that mimics HMC subcellular basement membrane and was found to modulate HMC adhesion, morphology and proliferation in vitro. Our results indicated that within minutes after plating, a high percentage (greater than 80%) of HMC firmly attached to ECM. Active cellular migration and subsequent proliferation were observed leading to the formation of a well-organized closely apposed cell monolayer. However, when cells were plated on plastic, the rate of cell attachment was much lower and the proliferative rate of HMC grown on plastic also was strikingly lower (exponential doubling time 4.3 days) than that of cells grown on ECM (exponential doubling time 2.4 days). Cells upon reaching confluency on plastic were markedly enlarged as compared to confluent cells grown on ECM. These observations corroborated differences in final cell density where it was noted that HMC cultured on ECM demonstrated a 10-fold greater final cell density as compared to cells grown on plastic. Results from these studies illustrate the fact that phenotypic expression as well as proliferative responsiveness of HMC can be modulated by adhesive interactions with preformed ECM.

Cell Adhesion↗
PubMed1986

Growth of human urological tumors on extracellular matrix as a model for the in vitro cultivation of primary human tumor explants.

The goal of this study was to establish an optimal in vitro growth assay system for human urological tumor explants. Bovine corneal endotelial cell extracellular matrix (ECM) coated dishes were evaluated as a growth substrate for tumor cultures. Growth success for different urological carcinomas (prostatic, bladder, kidney, and testicular) was compared after seeding fresh surgical explants onto bovine corneal endothelial cell ECM and plastic culture flasks. Tumor samples were disaggregated enzymatically, and 1 X 10(4) cells were seeded onto the different substrates using RPMI 1640 medium containing 10% fetal calf serum and/or different growth factors, nutrients, and hormones. Cell growth on ECM was quantitated on days 7-15 by [3H]thymidine uptake, cell counting, and total protein. Tumor cells were characterized by flow cytometry and cytology. It was observed that ECM provides superior culture conditions for urological carcinomas. By increasing the initial number of cells plated on ECM and by adding different growth factors or hormones, the growth rate for specific tumor types was increased significantly. Several tumors (11 cases) grown on ECM were examined under the light microscope, and in all cases pre- and post-cytology confirmed malignancy. Tumor cells maintained on ECM and transplanted into nude mide retained their tumorigenic and morphological characteristics. Clinically aggressive tumors were associated with extensive ECM degradation. In addition, the growth of fresh human tumors on ECM provides a biologically relevant model system (for assessing the invasiveness of tumors in vitro) and should also be useful for drug evaluation studies.

Cell Adhesion↗
PubMed1985

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.

Animals↗