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S Ruben

Publications and source records attributed to S Ruben.

At least 19 recordsLinked to original sources
PubMed2001

Expression and enzymatic activity of human disintegrin and metalloproteinase ADAM19/meltrin beta.

The adamalysins are involved in proteolysis, adhesion, fusion, and intracellular signaling. Human ADAM19/adamalysin-19 (A disintegrin and metalloproteinase 19) was identified from primary dendritic cell cDNA libraries. It has a signal sequence, a pro-domain with a "cysteine-switch" residue, a metalloproteinase domain with a zinc-binding site, a disintegrin, a cysteine-rich domain, an epidermal-growth-factor-like domain, a transmembrane domain, and a cytoplasmic domain with putative SH3 ligand binding sites. Its mRNA was expressed in the placenta, heart, bladder, lymph nodes, and leukocytes, colorectal adenocarcinoma SW 480, and other organs/cells. The hADAM19 recombinant protein was expressed in human cells. It formed a complex with and cleaved alpha-2 macroglobulin (alpha2-M). Its proteolytic activity was blocked by 1,10-phenanthroline, EDTA, EGTA, and a synthetic matrix metalloproteinase (MMP) inhibitor and not by the tissue inhibitors of metalloproteinases TIMP-1 and TIMP-2. It did not cleave the MMP substrates tested, e.g., type I collagen and gelatin, casein, and four peptide substrates. Thus, hADAM19 is an active metalloproteinase and may have a specific substrate profile.

ADAM Proteins↗
PubMed2000

Tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in androgen-independent prostate cancer cells.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been reported to induce cell death in a variety of transformed cells but spared the normal cells. In this study, we examined its potential against advanced prostate cancer cells. Treatment of PC-3 and DU145 cells with TRAIL caused a rapid apoptotic cell death, whereas tumor necrosis factor-alpha (TNF-alpha) is ineffective unless in the presence of the protein synthesis inhibitor cycloheximide. The induction of apoptosis by TRAIL in PC-3 cells was mediated by a death receptor, DR 4, and the downstream caspases. Treatment of PC-3 cells with TRAIL also activated c-Jun NH2-terminal kinase 1 (JNK1); however, inhibition of JNK1 activation by its dominant-negative mutant had little effect on TRAIL-induced apoptosis. Furthermore, TRAIL weakly stimulated nuclear factor kappaB activity in PC-3 cells. Interestingly, activation of nuclear factor kappaB pathway by pretreatment with TNF-alpha did not prevent the induction of apoptosis by TRAIL. These data indicate that TRAIL triggers apoptosis in advanced prostate cancer cells through the activation of caspase cascades, which appears to be independent of TNF-alpha- and JNK-mediated mechanisms.

Apoptosis↗
PubMed2000

Tumor rejection and immune memory elicited by locally released LEC chemokine are associated with an impressive recruitment of APCs, lymphocytes, and granulocytes.

The human beta chemokine known as LEC (also called NCC-4, HCC-4, or LMC) displays chemotactic activity for monocytes and dendritic cells. The possibility that its local presence increases tumor immunogenicity is addressed in this paper. TSA parental cells (TSA-pc) are poorly immunogenic adenocarcinoma cells that grow progressively, kill both nu/nu and syngeneic BALB/c mice, and give rise to lung metastases. TSA cells engineered to release LEC (TSA-LEC) are still able to grow in nu/nu mice, but are promptly rejected and display a marginal metastatic phenotype in BALB/c mice. Rejection is associated with a marked T lymphocyte and granulocyte infiltration, along with extensive macrophage and dendritic cell recruitment. NK cells and CD4+ T lymphocytes are uninfluential in TSA-LEC cell rejection, whereas both CD8+ lymphocytes and polymorphonuclear leukocytes play a major role. An antitumor immune memory is established very quickly after rejection, since 6 days later 75% of BALB/c mice were already resistant to a TSA-pc challenge. Spleen cells from rejecting mice display specific cytotoxic activity against TSA-pc and secrete IFN-gamma and IL-2 when restimulated by TSA-pc. The ability of LEC to markedly improve recognition of poorly immunogenic cells by promoting APC-T cell cross-talk suggests that it could be an effective component of antitumor vaccines.

Adenocarcinoma↗
PubMed2000

Lipoprotein lipase- and hepatic triglyceride lipase- promoted very low density lipoprotein degradation proceeds via an apolipoprotein E-dependent mechanism.

Apolipoprotein E (apoE) is the primary recognition signal on triglyceride-rich lipoproteins responsible for interacting with low density lipoprotein (LDL) receptors and LDL receptor-related protein (LRP). It has been shown that lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) promote receptor-mediated uptake and degradation of very low density lipoproteins (VLDL) and remnant particles, possibly by directly binding to lipoprotein receptors. In this study we have investigated the requirement for apoE in lipase-stimulated VLDL degradation. We compared binding and degradation of normal and apoE-depleted human VLDL and apoE knockout mouse VLDL in human foreskin fibroblasts. Surface binding at 37 degrees C of apoE knockout VLDL was greater than that of normal VLDL by 3- and 40-fold, respectively, in the presence of LPL and HTGL. In spite of the greater stimulation of surface binding, lipase-stimulated degradation of apoE knockout mouse VLDL was significantly lower than that of normal VLDL (30, 30, and 80%, respectively, for control, LPL, and HTGL treatments). In the presence of LPL and HTGL, surface binding of apoE-depleted human VLDL was, respectively, 40 and 200% of normal VLDL whereas degradation was, respectively, 25 and 50% of normal VLDL. LPL and HTGL stimulated degradation of normal VLDL in a dose-dependent manner and by a LDL receptor-mediated pathway. Maximum stimulation (4-fold) was seen in the presence LPL (1 microgram/ml) or HTGL (3 microgram/ml) in lovastatin-treated cells. On the other hand, degradation of apoE-depleted VLDL was not significantly increased by the presence of lipases even in lovastatin-treated cells. Surface binding of apoE-depleted VLDL to metabolically inactive cells at 4 degrees C was higher in control and HTGL-treated cells, but unchanged in the presence of LPL. Degradation of prebound apoE-depleted VLDL was only 35% as efficient as that of normal VLDL. Surface binding of apoE knockout or apoE-depleted VLDL was to heparin sulfate proteoglycans because it was completely abolished by heparinase treatment. However, apoE appears to be a primary determinant for receptor-mediated VLDL degradation. Our studies suggest that overexpression of LPL or HTGL may not protect against lipoprotein accumulation seen in apoE deficiency.

Animals↗
PubMed1999

A "stealth effect": adenocarcinoma cells engineered to express TRAIL elude tumor-specific and allogeneic T cell reactions.

BALB/c mammary adenocarcinoma cells engineered to express TNF-related apoptosis-inducing ligand (TRAIL)/APO-2 ligand (APO-2L) on their membrane (TSA-TRAIL) grow with kinetics similar to that of parental cells (TSA-pc) in vitro and in nu/nu mice. In contrast, TSA-TRAIL cells grow faster than TSA-pc in normal BALB/c mice. In DBA/2 mice, which differ from BALB/c mice at minor histocompatibility Ags, they also grow faster and display a higher percentage of tumor takes than TSA-pc. In fully histoincompatible C57BL/6 (B6) mice, TSA-TRAIL cells form evident tumors that are slowly rejected by most mice, but outgrow in a few. In contrast, TSA-pc cells are rejected at once by B6 mice. Since TRAIL/APO-2L induces apoptosis by interacting with a variety of specific receptors, this rapid growth in both syngeneic and allogeneic mice may be the result of an immunosuppressive mechanism. The following evidence supports this hypothesis: 1) TSA-TRAIL cells overcome the strong immunity against TSA-pc cells elicited in BALB/c mice by preimmunization with TSA cells engineered to release IL-4; 2) their rejection by B6 mice does not prime a CTL-mediated memory; 3) thymidine uptake by T lymphocytes unstimulated or stimulated by allogeneic cells is inhibited when TSA-TRAIL cells are added as third party cells; 4) CTL kill TSA-pc but not TSA-TRAIL cells in 48-h assays; and 5) activated lymphocytes interacting with TSA-TRAIL cells in vivo and in vitro undergo apoptosis.

Adenocarcinoma↗
PubMed1999

Computational EST database analysis identifies a novel member of the neuropoietic cytokine family.

A novel member of the neuropoietic cytokine family has been cloned and the protein expressed and characterized. In an effort to identify novel secreted proteins, an algorithm incorporating neural network algorithms was applied to a large EST database. A full-length clone was identified that is 1710 bp in length and has a single open reading frame of 225 amino acids. This new cytokine is most homologous to cardiotrophin-1, having a similarity and an identity of 46 and 29%, respectively, and therefore we have named it cardiotrophin-like cytokine (CLC). Northern hybridization analysis identified a 1.4-kb messenger RNA that is highly expressed in spleen and peripheral leukocytes. Purified recombinant CLC induced the activation of NFkappaB and SRE reporter constructs in the TF-1, U937, and M1 cell lines. Furthermore, the signal transduction pathway for CLC was characterized in the neuroblastoma cell line SK-N-MC and found to involve tyrosine phosphorylation of gp130 and STAT-1.

Amino Acid Sequence↗
PubMed1999

VEGI, a novel cytokine of the tumor necrosis factor family, is an angiogenesis inhibitor that suppresses the growth of colon carcinomas in vivo.

A novel member of the tumor necrosis factor (TNF) family has been identified from the human umbilical vein endothelial cell cDNA library, named vascular endothelial growth inhibitor (VEGI). The VEGI gene was mapped to human chromosome 9q32. The cDNA for VEGI encodes a protein of 174 amino acid residues with the characteristics of a type II transmembrane protein. Its amino acid sequence is 20-30% identical to other members of the TNF family. Unlike other members of the TNF family, VEGI is expressed predominantly in endothelial cells. Local production of a secreted form of VEGI via gene transfer caused complete suppression of the growth of MC-38 murine colon cancers in syngeneic C57BL/6 mice. Histological examination showed marked reduction of vascularization in MC-38 tumors that expressed soluble but not membrane-bound VEGI or were transfected with control vector. The conditioned media from soluble VEGI-expressing cells showed marked inhibitory effect on in vitro proliferation of adult bovine aortic endothelial cells. Our data suggest that VEGI is a novel angiogenesis inhibitor of the TNF family and functions in part by directly inhibiting endothelial cell proliferation. The results further suggest that VEGI maybe highly valuable toward angiogenesis-based cancer therapy.

Amino Acid Sequence↗
PubMed1999

Psychiatric disorders in first-degree relatives of patients with opiate dependence.

High rates of psychiatric disorders, particularly major depression, alcoholism, drug-use disorder and antisocial personality disorder in the relatives of opiate-dependent patients compared with normal controls, have been reported in some previous studies. This study was designed to evaluate the prevalence rates of drug-use and other psychiatric disorders in the first-degree relatives of opiate-dependent patients and compare these with rates in the first-degree relatives of surgical and psychiatric patients. A case-control study was conducted to compare the prevalence of psychiatric and drug-use disorders (which were estimated by the Family History Method) in 241 biological first-degree relatives of 50 opiate-dependent patients to that in 235 and 222 first-degree relatives of 50 surgical and 50 psychiatric patients respectively. The main outcome measure was the relative risk (expressed as odds ratio) of psychiatric and drug-use disorders. First-degree relatives of opiate-dependent patients were found to have significantly higher rates of drug-use and antisocial personality disorders, compared with relatives of surgical and psychiatric probands. The odds ratio for alcoholism appeared significantly higher only in first-degree female relatives of opiate users, suggesting effect modification by sex. The study provides further evidence for the higher rate of drug-use disorder in the first-degree relatives of opiate-dependent patients. These findings suggest that familial drug-use disorder contributes to a vulnerability to opiate misuse. Implications of these findings for the classification and treatment of opiate dependence are discussed.

Adult↗
PubMed1999

Hepatic triglyceride lipase promotes low density lipoprotein receptor-mediated catabolism of very low density lipoproteins in vitro.

We demonstrate here that hepatic triglyceride lipase (HTGL) enhances VLDL degradation in cultured cells by a LDL receptor-mediated mechanism. VLDL binding at 4 degrees C and degradation at 37 degrees C by normal fibroblasts was stimulated by HTGL in a dose-dependent manner. A maximum increase of up to 7-fold was seen at 10 microg/ml HTGL. Both VLDL binding and degradation were significantly increased (4-fold) when LDL receptors were up-regulated by treatment with lovastatin. HTGL also stimulated VLDL degradation by LDL receptor-deficient FH fibroblasts but the level of maximal degradation was 40-fold lower than in lovastatin-treated normal fibroblasts. A prominent role for LDL receptors was confirmed by demonstration of similar HTGL-promoted VLDL degradation by normal and LRP-deficient murine embryonic fibroblasts. HTGL enhanced binding and internalization of apoprotein-free triglyceride emulsions, however, this was LDL receptor-independent. HTGL-stimulated binding and internalization of apoprotein-free emulsions was totally abolished by heparinase indicating that it was mediated by HSPG. In a cell-free assay HTGL competitively inhibited the binding of VLDL to immobilized LDL receptors at 4 degrees C suggesting that it may directly bind to LDL receptors but may not bind VLDL particles at the same time. We conclude that the ability of HTGL to enhance VLDL degradation is due to its ability to concentrate lipoprotein particles on HSPG sites on the cell surface leading to LDL receptor-mediated endocytosis and degradation.

Animals↗
PubMed1998

LIGHT, a novel ligand for lymphotoxin beta receptor and TR2/HVEM induces apoptosis and suppresses in vivo tumor formation via gene transfer.

LIGHT is a new member of tumor necrosis factor (TNF) cytokine family derived from an activated T cell cDNA library. LIGHT mRNA is highly expressed in splenocytes, activated PBL, CD8(+) tumor infiltrating lymphocytes, granulocytes, and monocytes but not in the thymus and the tumor cells examined. Introduction of LIGHT cDNA into MDA-MB-231 human breast carcinoma caused complete tumor suppression in vivo. Histological examination showed marked neutrophil infiltration and necrosis in LIGHT expressing but not in the parental or the Neo-transfected MDA-MB-231 tumors. Interferon gamma (IFNgamma) dramatically enhances LIGHT-mediated apoptosis. LIGHT protein triggers apoptosis of various tumor cells expressing both lymphotoxin beta receptor (LTbetaR) and TR2/HVEM receptors, and its cytotoxicity can be blocked specifically by addition of a LTbetaR-Fc or a TR2/HVEM-Fc fusion protein. However, LIGHT was not cytolytic to the tumor cells that express only the LTbetaR or the TR2/HVEM or hematopoietic cells examined that express only the TR2/HVEM, such as PBL, Jurkat cells, or CD8(+) TIL cells. In contrast, treatment of the activated PBL with LIGHT resulted in release of IFNgamma. Our data suggest that LIGHT triggers distinct biological responses based on the expression patterns of its receptors on the target cells. Thus, LIGHT may play a role in the immune modulation and have a potential value in cancer therapy.

Apoptosis↗
PubMed1998

LIGHT, a new member of the TNF superfamily, and lymphotoxin alpha are ligands for herpesvirus entry mediator.

Herpes simplex virus (HSV) 1 and 2 infect activated T lymphocytes by attachment of the HSV envelope glycoprotein D (gD) to the cellular herpesvirus entry mediator (HVEM), an orphan member of the tumor necrosis factor receptor superfamily. Here, we demonstrate that HVEM binds two cellular ligands, secreted lymphotoxin alpha (LTalpha) and LIGHT, a new member of the TNF superfamily. LIGHT is a 29 kDa type II transmembrane protein produced by activated T cells that also engages the receptor for the LTalphabeta heterotrimer but does not form complexes with either LTalpha or LTbeta. HSV1 gD inhibits the interaction of HVEM with LIGHT, and LIGHT and gD interfere with HVEM-dependent cell entry by HSV1. This characterizes herpesvirus gD as a membrane-bound viokine and establishes LIGHT-HVEM as integral components of the lymphotoxin cytokine-receptor system.

Amino Acid Sequence↗
PubMed1997

A novel human Wnt gene, WNT10B, maps to 12q13 and is expressed in human breast carcinomas.

Several members of the Wnt gene family have been shown to cause mammary tumors in mouse. Using degenerate primer polymerase chain reaction (PCR) on human genomic DNA, and specific PCR of cDNA libraries, we have isolated a WNT gene which has not previously been described in human. The gene is the human homologue of mouse Wnt10b, recently shown to be one of the oncogenes cooperating with FGF3 in the development of mouse mammary tumour virus (MMTV) induced mouse mammary carcinomas. The human WNT10B sequence was 88% and 95% identical to the murine gene at nucleotide and amino acid levels, respectively. YAC FISH mapping localises the gene to 12q13, a chromosomal region frequently rearranged in human tumours and also containing the WNT1 gene. In normal and benign proliferations of human breast tissue, WNT10B expression was not detected by ribonuclease protection assays but was found at low levels in RT-PCR experiments. In contrast, using both methods, WNT10B expression was found to be elevated in 3 of 50 primary breast carcinomas. Southern blot analysis of the carcinoma expressing the highest levels of WNT10B showed no amplification or rearrangement of the gene. The WNT10B gene was also expressed in some cancer and non cancerous breast cell lines. These findings suggest that the WNT10B gene may be involved in human breast cancer, and show that there is differential expression of the WNT10B gene in benign and malignant disease.

Amino Acid Sequence↗
PubMed1997

Cloning and characterization of a novel human DNase.

The therapeutic significance of recombinant human DNase I in treating the patients with cystic fibrosis has risen our interests in identifying other human DNase I-like enzymes to study their biological significance. Here we described our work of cloning and characterization of a novel gene, which encodes a human protein homologous to human DNase I. A full length cDNA clone of this gene consists of 1290 bp, encoding a polypeptide of 306 amino acids. The deduced amino acid sequence of this novel human DNase (nhDNase) is 45% identical to that of human DNase I. Among sixteen human tissues examined by Northern Blot, high level expression of nhDNase was found in human liver and spleen. Recombinant protein of nhDNase was produced in a Baculovirus expression system and purified by chromatography and reverse-phase HPLC. Purified recombinant nhDNase migrated as a single band of about 33 kD molecular weight analyzed by SDS-PAGE. The DNase activity of nhDNase was demonstrated by assay of hydrolysis of S.S.DNA. Its activity was dependent upon the presence of divalent metal irons, calcium and magnesium. However, unlike bovine pancreas DNase I, nhDNase was not inhibited by G-actin of bovine muscle, which indicates the physiological significance of this enzyme in clinical implication.

Actins↗
PubMed1997

Serum levels of unbound free fatty acids. I: Normative data in term newborn infants.

BACKGROUND: Free fatty acids (FFA) play essential roles in maintaining physiologic homeostasis in the newborn infant. Most of the FFA in serum is carried in complex with albumin, but a small fraction remains unbound in the aqueous phase. OBJECTIVE: This study's goal is to report the values of serum levels of unbound free fatty acids (FFAu) in pregnant women and their newborn infants at term gestation. METHODS: The measurements were made possible by the availability of the fluorescent probe for unbound FFA, acrylodated intestinal fatty acid binding protein (ADIFAB). Twenty-two mother-infant pairs were enrolled in the study. Maternal levels were obtained immediately before delivery, cord levels at the time of delivery, and infant levels after 24 hours of age. RESULTS: The level of FFAu measured in maternal samples was 11.8 +/- 4 nM, in cord samples 9.2 +/- 4 nM, and in infants 13.9 +/- 3 nM. These population averages are considerably greater than those observed in healthy adults (7.5 +/- 2.5 nM). No correlation was found between cord levels and birthweight, gestational age, labor duration, mode of deliver, and infant or maternal temperature. CONCLUSIONS: This investigation is the first to measure FFAu in a group of mothers and their infants and provides the technique for future investigations of the biologic activity of free fatty acids.

Adult↗
PubMed1997

Serum levels of unbound free fatty acids. II: The effect of intralipid administration in premature infants.

BACKGROUND: Fatty acids (FFA) are key nutrients in maintaining physiologic homeostasis and in the form of Intralipid administration, they are important sources of nutrition in the premature newborn infant. Complexed with albumin, fatty acids have a small but important fraction that remains unbound in the aqueous phase. OBJECTIVE: The goal of this study was to examine the levels of serum levels of unbound free fatty acids (FFAu) in premature newborns following Intralipid administration. METHOD: A fluorescent probe acrylodated intestinal fatty acid binding protein (ADIFAB) was used to measure (FFAu) before Intralipid and during increasing rates of infusion. RESULTS: There were significant differences between (FFAu) values obtained before Intralipid and levels after the infusion of 1.0, 2.0, and 3.0 g/kg/day (p < 0.05). Regression analysis of Intralipid dose and FFAu yielded an r = 0.438 and the following relationship: [FFAu] = 26.39 + 3.60 * IL (g/kg/day). CONCLUSIONS: Intralipid administration results in significant elevation of FFAu in the very low birth weight infant.

Fat Emulsions, Intravenous↗
PubMed1997

A novel regulatory function of proteolytically cleaved VEGF-2 for vascular endothelial and smooth muscle cells.

By high throughput sequencing, we have identified a cDNA encoding a polypeptide related to vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) in the VEGF/PDGF gene family. It is designated vascular endothelial growth factor 2 (VEGF-2). Similar to VEGF, expression of VEGF-2 mRNA is abundant in vascular smooth muscle cells and several highly vascularized tissues. VEGF-2 protein is expressed as a secreted 52 kDa precursor as well as the 30 kDa amino-terminal and 27 kDa carboxy-terminal cleavage products. The latter two cleavage products are linked via a disulfide bridge (or bridges) and can be copurified. Using copurified 30 and 27 kDa proteins, the effect of VEGF-2 on growth of several cell types, including vascular endothelial and smooth muscle cells, was determined. Our results demonstrate that VEGF-2 protein stimulates the growth of human vascular endothelial cells but inhibits growth of human aortic smooth muscle cells induced by platelet-derived growth factor. These studies establish VEGF-2 as a novel regulator for growth of vascular endothelial and smooth muscle cells.

Amino Acid Sequence↗
PubMed1996

Lipoprotein lipase binds to low density lipoprotein receptors and induces receptor-mediated catabolism of very low density lipoproteins in vitro.

Lipoprotein lipase (LPL), the major enzyme responsible for the hydrolysis of plasma triglycerides, promotes binding and catabolism of triglyceride-rich lipoproteins by various cultured cells. Recent studies demonstrate that LPL binds to three members of the low density lipoprotein (LDL) receptor family, including the LDL receptor-related protein (LRP), GP330/LRP-2, and very low density lipoprotein (VLDL) receptors and induces receptor-mediated lipoprotein catabolism. We show here that LDL receptors also bind LPL and mediate LPL-dependent catabolism of large VLDL with Sf 100-400. Up-regulation of LDL receptors by lovastatin treatment of normal human foreskin fibroblasts (FSF cells) resulted in an increase in LPL-induced VLDL binding and catabolism to a level that was 10-15-fold greater than in LDL receptor-negative fibroblasts, despite similar LRP activity in both cell lines. This indicates that the contribution of LRP to LPL-dependent degradation of VLDL is small when LDL receptors are maximally up-regulated. Furthermore studies in LRP-deficient murine embryonic fibroblasts showed that the level of LPL-dependent degradation of VLDL was similar to that in normal murine embryonic fibroblasts. LPL also promoted the internalization of protein-free triglyceride emulsions; lovastatin-treatment resulted in 2-fold higher uptake in FSF cells, indicating that LPL itself could bind to LDL receptors. However, the lower induction of emulsion catabolism as compared with native VLDL suggests that LPL-induced catabolism via LDL receptors is only partially dependent on receptor binding by LPL and instead is primarily due to activation of apolipoproteins such as apoE. A fusion protein between glutathione S-transferase and the catalytically inactive carboxyl-terminal domain of LPL (GST-LPLC) also induced binding and catabolism of VLDL. However GST-LPLC was not as active as native LPL, indicating that lipolysis is required for a maximal LPL effect. Mutations of critical tryptophan residues in GST-LPLC that abolished binding to VLDL converted the protein to an inhibitor of lipoprotein binding to LDL receptors. In solid-phase assays using immobilized receptors, LDL receptors bound to LPL in a dose-dependent manner. Both LPL and GST-LPLC promoted binding of VLDL to LDL receptor-coated wells. These results indicate that LPL binds to LDL receptors and suggest that the carboxyl-terminal domain of LPL contributes to this interaction.

Alanine↗