Serum glutathione-S-transferase and glutathione reductase activity in head and neck cancer patients

Glutathione, an antioxidant plays an important role in phase-II detoxification of carcinogens. The levels of reduced glutathione are maintained by glutathione-depleting as well as replenishing enzymes such as glutathione-s-transferase (GST) and glutathione reductase (GR), respectively. Pre and post treatment changes in GST and GR activities in head and neck cancer patients were analysed. Serum GST and GR were analysed from untreated head and neck cancer patients (PT) (n=146), controls with habit of tobacco (VHT) (n=25) as well as without (no) habit of tobacco (NHT) (n=25) and patients with oral precancerous conditions (OPC) (n=50). The cancer patients were followed-up after initiation of anticancer therapy. Follow-up blood samples were collected. Serum GST and GR activities were estimated by highly sensitive and specific spectrophotometric methods. Untreated cancer patients showed elevated mean serum GST and GR activities as compared to NHT. Patients with OPC had declined mean GST activity as compared to WHT and untreated cancer patients. Paired t-test revealed that complete responders (CR) showed significantly elevated GST levels and declined GR activities (p < 0.001) as compared to those in PT. No correlation was found between stage of the disease and GST, GR activity. Paired t-test showed significant decreased in GR activity in nonresponders (NR) treated with radiotherapy (p=0.01). The study suggested that analysis of glutathione and glutathione-depleting enzymes can be helpful for treatment monitoring of head and neck cancer patients.

T-Cell recovery in adults and children following umbilical cord blood transplantation

T-cell reconstitution following allogeneic stem cell transplantation may involve thymic education of donor-derived precursors or peripheral expansion of mature T cells transferred in the graft. T cell-receptor excision circles (sjTRECs) are generated within the thymus and identify new thymic emigrants and those that have not divided. We measured quantitative and qualitative immunologic reconstitution and sjTREC levels in adult and pediatric recipients of umbilical cord blood transplants (UCBTs). sjTRECs were detected at normal levels in all children, starting 12 months after transplantation. sjTRECs were not detected until 18 months after transplantation in adults, and then only at a 3-fold lower level than expected for age. We used complementarity-determining region 3 (CDR3) spectratyping to measure changes in T cell-receptor diversity occurring with restoration of thymic function. T-cell repertoires were skewed in adults and children at 12 to 18 months after transplantation but recovered to near-normal diversity at 2 to 3 years post-UCBT. T-cell repertoires appeared more diverse earlier in children (at 1 to 2 years post-UCBT) than in adults (at 3 to 4 years post-UCBT). We conclude that early T-cell recovery after UCBT occurs primarily through peripheral expansion of adoptively transferred donor T cells and results in skewing of the T-cell repertoire. The reappearance of sjTREC-containing cells after UCBT is associated with increasing numbers of phenotypicaly naive T cells, improved mitogen and recall antigen responses, and diversification of the T-cell repertoire. The delay in central T-cell recovery in adults relative to children may be due to differences in thymic function resulting from age-related atrophy, graft-versus-host disease, or the pharmacologic effects of prophylaxis and treatment of graft-versus-host disease.

Role of pretherapeutic biomarkers in predicting postoperative radiotherapy response in patients with advanced squamous cell carcinoma

PURPOSE

To assess the role of biomarker levels in predicting radiotherapy (RT) response in patients with squamous cell carcinoma of buccal mucosa treated with postoperative RT.

MATERIALS AND METHODS

Thirty-one patients with squamous cell carcinoma of buccal mucosa who received postoperative RT were enrolled for the study. Glutathione S-transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD) and catalase activity were analysed from primary tumour and adjacent normal mucosa of the same patients before RT. p53 and p21ras were localized immunohistochemically.

RESULTS

Enzyme activation was predicted by comparing the levels of these enzymes in tumour and adjacent normal mucosa. Deactivation of GST, activation of GR, SOD and catalase were associated with poor response to RT. p53 immunoreactivity was associated with failure to respond to RT.

CONCLUSIONS

These markers may be useful in predicting treatment outcome in patients receiving postoperative RT, although this conclusion requires confirmation in a larger group of patients.

Characterization of the rodent genes for arylacetamide deacetylase, a putative microsomal lipase, and evidence for transcriptional regulation

In the current study, we have determined the cDNA and the genomic sequences of the arylacetamide deacetylase (AADA) gene in mice and rats. The AADA genes in the rat and mouse consist of five exons and have 2.4 kilobases of homologous promoter sequence upstream of the initiating ATG codon. AADA mRNA is expressed in hepatocytes, intestinal mucosal cells (probably enterocytes), the pancreas and also the adrenal gland. In mice, there is a diurnal rhythm in hepatic AADA mRNA concentration, with a maximum 10 h into the light (post-absorptive) phase. This diurnal regulation is attenuated in peroxisome proliferator-activated receptor alpha knockout mice. Intestinal but not hepatic AADA mRNA was increased following oral administration of the fibrate, Wy-14,643. The homology of AADA with hormone-sensitive lipase and the tissue distribution of AADA are consistent with the view that AADA plays a role in promoting the mobilization of lipids from intracellular stores and in the liver for assembling VLDL. This hypothesis is supported by parallel changes in AADA gene expression in animals with insulin-deficient diabetes and following treatment with orotic acid.

Mutational analysis of the fractalkine chemokine domain. Basic amino acid residues differentially contribute to CX3CR1 binding, signaling, and cell adhesion

Fractalkine (FKN/CX3CL1) is a unique member of the chemokine gene family and contains a chemokine domain (CD), a mucin-like stalk, a single transmembrane region, and a short intracellular C terminus. This structural distinction affords FKN the property of mediating capture and firm adhesion of FKN receptor (CX3CR1)-expressing cells under physiological flow conditions. Shed forms of FKN also exist, and these promote chemotaxis of CX3CR1-expressing leukocytes. The goal of the present study was to identify specific residues within the FKN-CD critical for FKN-CX3CR1 interactions. Two residues were identified in the FKN-CD, namely Lys-7 and Arg-47, that are important determinants in mediating an FKN-CX3CR1 interaction. FKN-K7A and FKN-R47A mutants exhibited 30-60-fold decreases in affinity for CX3CR1 and failed to arrest efficiently CX3CR1-expressing cells under physiological flow conditions. However, these mutants had differential effects on chemotaxis of CX3CR1-expressing cells. The FKN-K7A mutant acted as an equipotent partial agonist, whereas the FKN-R47A mutant had marked decreased potency and efficacy in measures of chemotactic activity. These data identify specific structural features of the FKN-CD that are important in interactions with CX3CR1 including steady state binding, signaling, and firm adhesion of CX3CR1-expressing cells.

Determinants of Variable Response to Statin Treatment in Patients With Refractory Familial Hypercholesterolemia

Abstract —Interindividual variability in low density lipoprotein (LDL) cholesterol (LDL-C) response during treatment with statins is well documented but poorly understood. To investigate potential metabolic and genetic determinants of statin responsiveness, 19 patients with refractory heterozygous familial hypercholesterolemia were sequentially treated with placebo, atorvastatin (10 mg/d), bile acid sequestrant, and the 2 combined, each for 4 weeks. Levels of LDL-C, mevalonic acid (MVA), 7-α-OH-4-cholesten-3-one, and leukocyte LDL receptor and hydroxymethylglutaryl coenzyme A reductase mRNA were determined after each treatment period. Atorvastatin (10 mg/d) reduced LDL-C by an overall mean of 32.5%. Above-average responders (ΔLDL-C −39.5%) had higher basal MVA levels (34.4±6.1 μmol/L) than did below-average responders (ΔLDL-C −23.6%, P <0.02; basal MVA 26.3±6.1 μmol/L, P <0.01). Fewer good responders compared with the poor responders had an apolipoprotein E4 allele (3 of 11 versus 6 of 8, respectively; P <0.05). There were no baseline differences between them in 7-α-OH-4-cholesten-3-one, hydroxymethylglutaryl coenzyme A reductase mRNA, or LDL receptor mRNA, but the latter increased in the good responders on combination therapy ( P <0.05). Severe mutations were not more common in poor than in good responders. We conclude that poor responders to statins have a low basal rate of cholesterol synthesis that may be secondary to a genetically determined increase in cholesterol absorption, possibly mediated by apolipoprotein E4. If so, statin responsiveness could be enhanced by reducing dietary cholesterol intake or inhibiting absorption.

Molecular markers are predictors of recurrence and survival in patients with Dukes B and Dukes C colorectal adenocarcinoma

PURPOSE

The goal was to investigate the prognostic value of various molecular markers like CEA, Cyclin D1, Bcl-2, c-Myc, p53, p21ras, Ki-67, CD44, Factor VIII-related antigen, cytokeratin-19, adenoma antigen, and prolactin in patients with Dukes B and Dukes C colorectal adenocarcinoma.

METHODS

These molecular markers were localized immunohistochemically in nonmalignant (n = 36) and malignant (n = 98) diseases of the colorectum. Data were analyzed statistically using the SPSS software program. The patients with colorectal cancer were followed for a period of five years or their death within that period.

RESULTS

The expression of carcinoembryonic antigen, Cyclin D1, Bcl-2, CD44, cytokeratin-19 and prolactin was significantly higher in malignant diseases (P < 0.05), whereas, p21ras was found to be significantly higher in nonmalignant diseases (P = 0.002) as compared with their respective counterparts. Besides Dukes stage, multivariate analysis indicated a significantly reduced relapse-free survival in patients expressing CD44 and cytokeratin-19 (P < 0.005). Similarly, besides Dukes stage, multivariate analysis indicated a significantly poor overall survival in patients expressing CD44, cytokeratin-19 and prolactin (P < 0.01). In patients with Dukes B disease, only cytokeratin-19 and CD44 expression attained statistical significance (P < 0.05), whereas in patients with Dukes C disease, CD44, p21ras- and c-Myc expression attained statistical significance (P < 0.018). Also, a multivariate analysis in relation to treatment given was performed using CD44 and cytokeratin-19.

CONCLUSION

Besides Dukes stage, multivariate analysis of all the studied molecular markers showed that patients expressing CD44 and cytokeratin-19 had a significantly reduced relapse-free and poor overall survival. Moreover, patients expressing both these markers (CD44 and cytokeratin-19) had the lowest significant relative risk for developing recurrence than patients with both markers negative when treated with surgery followed by adjuvant chemotherapy as compared with patients treated with surgery alone. Thus, in patients with colorectal cancer, immunohistochemical localization of CD44 and cytokeratin-19 may be included as a part of routine pathologic evaluation along with conventional prognostic factors.

Chemokines have diverse abilities to form solid phase gradients

Chemokines play critical roles in leukocyte recruitment into sites of inflammation such as rheumatoid arthritis (RA). While chemokines immobilized on endothelium (solid-phase), but not soluble chemokines, direct rolling leukocytes to firmly adhere to endothelium, soluble and solid-phase chemokine gradients may play important roles in leukocyte extravasation into the tissue. In this study, we have sought to determine (1) if chemokines can be immobilized on structures in the extravascular space, (2) the mechanisms by which chemokines may be immobilized, and (3) if different chemokines have similar potentials to form solid-phase gradients. While secreted alkaline phosphatase (SEAP)-tagged chemokines SLC (CCL21), TARC (CCL17), and RANTES (CCL5) bound to mast cells and the extracellular matrix (ECM) in RA synovium under physiologic salt conditions, MCP1 (CCL2), MIP1 alpha (CCL3), MIP1 beta (CCL4), and fractalkine (FKN, CX3CL1) fusion proteins did not detectably bind. Chemokine binding to ECM and mast cells in situ and to immobilized heparin was inhibited by high salt and glycosaminoglycans (GAGs) heparin, heparan sulfate, chondroitin sulfate, and dermatan sulfate, but not by dextran or hyaluronan, indicating that the chemokines bind to highly sulfated GAGs. Chemokine binding to synovial structures correlated strongly with avidity of chemokine binding to heparin (SLC > TARC > RANTES > MIP1 beta > MCP1 > MIP1 alpha > FKN). A RANTES mutant with decreased avidity for heparin was not able to bind to ECM or mast cells. Thus, these data indicate that chemokines can bind to ECM and mast cell granule constituents in situ via interactions with GAGs. Further, only a subset of chemokines were able to bind efficiently to structures in the extravascular space, indicating that chemokines may form different types of gradients based on their GAG binding ability and that chemotactic gradients in tissues may be quite complex.

A study of chromosome aneuploidy in hereditary breast cancer patients and their healthy blood relatives

Chromosomal abnormalities that may predispose a group of individuals to develop certain neoplasms have been reported in lymphocytes. We evaluated cytogenetic abnormalities in 21 histopathologically confirmed primary breast cancer patients (BCPs), 52 healthy blood relatives (HBRs), belonging to 19 hereditary breast cancer families (HBFs) and 25 females as control. Phytohemagglutinin stimulated peripheral blood lymphocyte (PBL) cultures were used to study the chromosomal abnormalities in BCPs and their HBRs. Short term culture of the tumor tissue was also carried out in defined growth medium. Suitable metaphases (11 to 55) from tumors and a minimum of 100 metaphases from PBL were karyotyped for the cytogenetic analysis. Heterogeneous population of cells with random and nonrandom chromosomal abnormalities was noticed in tumors. In control groups 2-5% of metaphases showed numerical abnormalities, whereas this phenomenon was observed in 3-18% of metaphases in HBRs and 3-23% of metaphases in BCPs. In tumor tissue, 47.05% of BCPs showed numerical abnormalities in more than 16 metaphases. In lymphocytes, this event was observed in 33.33% of BCPs and 13.14% of HBRs. In controls 1.28%, in BCPs 52.04% (tumor) and 13.42% (lymphocytes), and in HBRs 9.03% of metaphases were found aneuploid. Statistically it was highly significant (Fisher's exact test, P<0.00001). In lymphocytes of BCPs, chromosomes 1, 6, 8, 9, 15, 17, 18, 20, and X and in HBRs, chromosomes 8, 15, 17, 18, and X were frequently involved. It can be inferred from the findings that the above mentioned chromosomes may have an important role in early stage of breast carcinogenesis in BCFs. Moreover, presence of similar abnormalities in HBR indicates inherited pattern of this genetic error among them.

Self-antigen-presenting cells expressing diabetes-associated autoantigens exist in both thymus and peripheral lymphoid organs

Recent reports indicate that genes with tissue-restricted expression, including those encoding the type 1 diabetes autoantigens insulin, glutamic acid decarboxylase (GAD), and the tyrosine-phosphatase-like protein IA-2 (or ICA512), are transcribed in the thymus. The reported modulation of diabetes susceptibility by genetically determined differences in thymic insulin levels and studies in transgenic mice provide correlative and functional evidence that thymic expression of peripheral proteins is crucial for immunological self-tolerance. However, there are no specific data about the existence, tissue distribution, phenotype, and function of those cells that express insulin and other self-antigens in the human thymus. We find that the human thymus harbors specialized cells synthesizing (pro)insulin, GAD, and IA-2, mainly localized in the medulla, and we demonstrate such cells also in peripheral lymphoid organs (spleen and lymph nodes). Phenotypic analysis qualifies these cells as antigen-presenting cells (APCs), including both dendritic cells and macrophages. These cells often appear surrounded by apoptotic lymphocytes, both in thymus and spleen, and may therefore be involved in the deletion of autoreactive lymphocytes. Our findings demonstrate the existence of, and define the tissue distribution and phenotype of, a novel subset of APCs expressing self-antigens in human lymphoid organs that appear to be involved in the regulation of self-tolerance throughout life.

Disturbances in the normal regulation of SREBP-sensitive genes in PPAR alpha-deficient mice

Peroxisome proliferator-activated receptor alpha (PPAR alpha)-null mice were used to investigate the nature of the relationship between the normal circadian rhythm of hepatic PPAR alpha expression and the expression of the lipogenic and cholesterogenic sterol regulatory element-binding protein (SREBP)-regulated genes, acetyl-CoA carboxylase, fatty acid synthase (FAS), and 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoAR). The expression of FAS and HMG-CoAR varied rhythmically over the diurnal cycle in the normal mice, with patterns that were the opposite of that of PPAR alpha. The diurnal variation of lipogenic and cholesterogenic gene expression was attenuated or abolished in the PPAR alpha-null mice. This resulted in decreased expression compared with normal mice, but only during the dark phase of the cycle, when food intake was high. The diurnal variation in hepatic fatty acid and cholesterol synthesis was also abolished in the PPAR alpha-null animals and the variations in the concentration of plasma triacylglycerol, nonesterified fatty acids, and cholesterol were all attenuated. The failure of HMG-CoAR expression to increase during the feeding period in the PPAR alpha-null mice was associated with a decrease in hepatic nonesterified cholesterol content and an increase in cholesteryl ester compared with normal mice. There was no defect in the downregulation of hepatic HMG-CoAR mRNA in response to dietary cholesterol in the PPAR alpha-null mice. Under these conditions, hepatic PPAR gamma expression increased in both the control and PPAR alpha-deficient mice. The results suggest that PPAR alpha-deficiency disturbs the normal circadian regulation of certain SREBP-sensitive genes in the liver, but does not affect their response to dietary cholesterol. -- Patel, D. D., B. L. Knight, D. Wiggins, S. M. Humphreys, and G. F. Gibbons. Disturbances in the normal regulation of SREBP-sensitive genes in PPAR alpha-deficient mice. J. Lipid Res. 2001. 42: 328--337.

Comparison of thymocyte development and cytokine production in CD7-deficient, CD28-deficient and CD7/CD28 double-deficient mice

CD7 and CD28 are Ig superfamily molecules expressed on thymocytes and mature T cells that share common signaling 0mechanisms and are co-mitogens for T cell activation. CD7-deficient mice are resistant to lipopolysaccharide (LPS)-induced shock syndrome, and have diminished in vivo LPS-triggered IFN-gamma and tumor necrosis factor (TNF)-alpha production. CD28-deficient mice have decreased serum Ig levels, defective IgG isotype switching, decreased T cell IL-2 production and are resistant to Staphylococcus aureus enterotoxin-induced shock. To determine synergistic roles CD7 and CD28 might play in thymocyte development and function, we have generated and characterized CD7/CD28 double-deficient mice. CD7/CD28-deficient mice were healthy, reproduced normally, had normal numbers of thymocyte subsets and had normal thymus histology. Anti-CD3 mAb induced similar levels of apoptosis in CD7-deficient, CD28-deficient and CD7/CD28 double-deficient thymocytes as in control C57BL/6 mice (P = NS). Similarly, thymocyte viability, apoptosis and necrosis following ionomycin or dexamethasone treatment were the same in control, CD7-deficient, CD28-deficient and CD7/CD28-deficient mice. CD28-deficient and CD7/CD28-deficient thymocytes had decreased [3H]thymidine incorporation responses to concanavalin A (Con A) stimulation compared to control mice (P < or = 0.01 and P < or = 0.05 respectively). CD7/CD28 double-deficient mice had significantly reduced numbers of B7-1/B7-2 double-positive cells compared to freshly isolated wild-type, CD7-deficient and CD28-deficient thymocytes. Con A-stimulated CD4/CD8 double-negative (DN) thymocytes from CD7/CD28 double-deficient mice expressed significantly lower levels of CD25 when compared to CD4/CD8 DN thymocytes from wild-type, CD7-deficient and CD28-deficient mice (P < 0.05). Anti-CD3-triggered CD7/CD28-deficient thymocytes also had decreased IFN-gamma and TNF-alpha production compared to C57BL/6 control, CD7-deficient and CD28-deficient mice (P < or = 0.05). Thus, CD7 and CD28 deficiencies combined to produce abnormalities in the absolute number of B7-1/B7-2-expressing cells in the thymus, thymocyte IL-2 receptor expression and CD3-triggered cytokine production.

Ectopic production of prolactin by colorectal adenocarcinoma

PURPOSE

This study assessed the role of prolactin in patients with Dukes B and C colorectal carcinoma.

METHODS

Circulating prolactin and carcinoembryonic antigen were assayed using immunoradiometric assay and radioimmunoassay kits, respectively, in preoperative blood (n = 98) and tumor-draining venous blood (n = 34) samples of colorectal carcinoma patients. Immunohistochemical localization of prolactin (n = 98), carcinoembryonic antigen (n = 98), and prolactin receptors (n = 56) was performed. The expression of prolactin messenger ribonucleic acid (n = 50) and prolactin receptor messenger ribonucleic acid (n = 50) was studied by reverse transcriptase polymerase chain reaction. Further, prolactin amplimer was sequenced.

RESULTS

Preoperative prolactin and carcinoembryonic antigen levels were significantly higher in patients with colorectal carcinoma than in controls (prolactin, P = 0.001; carcinoembryonic antigen, P = 0.0001). Univariate survival analysis showed that Dukes stage, histologic grade, and circulating prolactin were significant prognostic factors for determining overall survival (Dukes stage, P = 0.00001; histologic grade, P = 0.005; prolactin, P = 0.001). In multivariate analysis, besides Dukes stage, circulating prolactin emerged as the most significant independent prognostic factor influencing overall survival. Preoperative prolactin levels showed excellent significant correlation with response to therapy and progression of disease. A significant tenfold higher mean concentration of prolactin was observed in tumor-draining venous blood than in peripheral blood (P = 0.0001). Diffuse cytoplasmic staining for prolactin was seen in 51 percent (50/98) of the colorectal carcinomas. Prolactin messenger ribonucleic acid expression was seen in 88 percent (44/50) of the colorectal carcinomas. Sequence analysis of the 234-bp prolactin amplimer revealed that the sequence was homologous to exon 5 of pituitary prolactin messenger ribonucleic acid.

CONCLUSION

These multiple approaches confirmed that prolactin is produced by colorectal carcinoma cells. Looking at its prognostic value and correlation with disease activity, it may provide new insights into treatment for patients with colorectal carcinoma.

CXCR3 and CCR5 ligands in rheumatoid arthritis synovium

The pathogenesis of rheumatoid arthritis (RA) may be mediated by Th1-type T cells. Since chemokine receptors CXCR3 and CCR5 are preferentially expressed on Th1 cells, we tested the expression and regulation of several chemokines, including those that signal through CXCR3 (interferon-gamma-inducible protein of 10 kDa, IP-10, CXCL10; and monokine induced by interferon-gamma, Mig, CXCL9) and CCR5 (macrophage inflammatory protein (Mip)-1 alpha, CCL3; and Mip-1 beta, CCL4) in RA synovial fluids, synovial tissues, and blood. Synovial fluid (SF) protein levels of IP-10 (32.1 +/- 10.5 ng/ml), Mig (15.0 +/- 6.4 ng/ml), Mip-1 beta (0.7 +/- 0.3 ng/ml), and Mip-1 alpha (0.8 +/- 0.1 ng/ml) were 100-, 50-, 25-, and 2-fold elevated in RASF compared to control SF (P < 0.001, P < 0.001, P < 0. 001, and P < 0.02, respectively). Tissue levels of IP-10, Mig, and Mip-1 beta were significantly higher in RA than in OA (P < 0.01). Serum levels of IP-10 (3.1 +/- 1.2 ng/ml) were higher in patients with seropositive RA compared to controls (1.2 +/- 0.2 ng/ml) (P < 0.02). There was a gradient of IP-10, Mig, Mip-1 alpha, and Mip-1 beta from the blood into the synovial fluid in RA. Infiltrating T cells around high endothelial venules in RA synovium and 90 +/- 3% of SF CD3(+)CD4(+) T cells expressed CXCR3, and 85 +/- 2% of SF CD3(+)CD4(+) T cells expressed CCR5. Chemokines, including IP-10, Mig, Mip-1 alpha, and Mip-1 beta, may participate in the selective recruitment of CCR5(+)CXCR3(+) T cells to the inflamed synovium.

The development of clinical signs of rheumatoid synovial inflammation is associated with increased synthesis of the chemokine CXCL8 (interleukin-8)

Paired synovial tissue samples were obtained from both clinically uninvolved (CU) and clinically involved (CI) knee joints of eight rheumatoid arthritis (RA) patients. In addition, biopsies were taken from five control subjects. We observed the expression of the chemokines CXCL8, CXCL9, CXCL10, CCL2 and CCL4 in CI and CU joints of RA patients. In particular, CXCL8 protein levels were specifically increased in CI joints compared with CU joints, which was confirmed by immunohistochemistry and in situ hybridization.

Chemokine production by G protein-coupled receptor activation in a human mast cell line: roles of extracellular signal-regulated kinase and NFAT

Chemoattractants are thought to be the first mediators generated at sites of bacterial infection. We hypothesized that signaling through G protein-coupled chemoattractant receptors may stimulate cytokine production. To test this hypothesis, a human mast cell line (HMC-1) that normally expresses receptors for complement components C3a and C5a at low levels was stably transfected to express physiologic levels of fMLP receptors. We found that fMLP, but not C3a or C5a, induced macrophage inflammatory protein (MIP)-1ss (CCL4) and monocyte chemoattractant protein-1 (CCL2) mRNA and protein. Although fMLP stimulated both sustained Ca(2+) mobilization and phosphorylation of extracellular signal-regulated kinase (ERK), these responses to C3a or C5a were transient. However, transient expression of C3a receptors in HMC-1 cells rendered the cells responsive to C3a for sustained Ca(2+) mobilization and MIP-1ss production. The fMLP-induced chemokine production was blocked by pertussis toxin, PD98059, and cyclosporin A, which respectively inhibit G(i)alpha activation, mitgen-activated protein kinase kinase-mediated ERK phosphorylation, and calcineurin-mediated activation of NFAT. Furthermore, fMLP, but not C5a, stimulated NFAT activation in HMC-1 cells. These data indicate that chemoattractant receptors induce chemokine production in HMC-1 cells with a selectivity that depends on the level of receptor expression, the length of their signaling time, and the synergistic interaction of multiple signaling pathways, including extracellular signal-regulated kinase phosphorylation, sustained Ca(2+) mobilization and NFAT activation.

A role for fractalkine and its receptor (CX3CR1) in cardiac allograft rejection

The hallmark of acute allograft rejection is infiltration of the inflamed graft by circulating leukocytes. We studied the role of fractalkine (FKN) and its receptor, CX(3)CR1, in allograft rejection. FKN expression was negligible in nonrejecting cardiac isografts but was significantly enhanced in rejecting allografts. At early time points, FKN expression was particularly prominent on vascular tissues and endothelium. As rejection progressed, FKN expression was further increased, with prominent anti-FKN staining seen around vessels and on cardiac myocytes. To determine the capacity of FKN on endothelial cells to promote leukocyte adhesion, we performed adhesion assays with PBMC and monolayers of TNF-alpha-activated murine endothelial cells under low-shear conditions. Treatment with either anti-FKN or anti-CX(3)CR1-blocking Ab significantly inhibited PBMC binding, indicating that a large proportion of leukocyte binding to murine endothelium occurs via the FKN and CX(3)CR1 adhesion receptors. To determine the functional significance of FKN in rejection, we treated cardiac allograft recipients with daily injections of anti-CX(3)CR1 Ab. Treatment with the anti-CX(3)CR1 Ab significantly prolonged allograft survival from 7 +/- 1 to 49 +/- 30 days (p < 0.0008). These studies identify a critical role for FKN in the pathogenesis of acute rejection and suggest that FKN may be a useful therapeutic target in rejection.

The binding site of human adenosine deaminase for CD26/Dipeptidyl peptidase IV: the Arg142Gln mutation impairs binding to cd26 but does not cause immune deficiency

Human, but not murine, adenosine deaminase (ADA) forms a complex with the cell membrane protein CD26/dipeptidyl peptidase IV. CD26-bound ADA has been postulated to regulate extracellular adenosine levels and to modulate the costimulatory function of CD26 on T lymphocytes. Absence of ADA-CD26 binding has been implicated in causing severe combined immunodeficiency due to ADA deficiency. Using human-mouse ADA hybrids and ADA point mutants, we have localized the amino acids critical for CD26 binding to the helical segment 126-143. Arg142 in human ADA and Gln142 in mouse ADA largely determine the capacity to bind CD26. Recombinant human ADA bearing the R142Q mutation had normal catalytic activity per molecule, but markedly impaired binding to a CD26(+) ADA-deficient human T cell line. Reduced CD26 binding was also found with ADA from red cells and T cells of a healthy individual whose only expressed ADA has the R142Q mutation. Conversely, ADA with the E217K active site mutation, the only ADA expressed by a severely immunodeficient patient, showed normal CD26 binding. These findings argue that ADA binding to CD26 is not essential for immune function in humans.

The effect of peroxisome-proliferator-activated receptor-alpha on the activity of the cholesterol 7 alpha-hydroxylase gene

Cholesterol 7 alpha-hydroxylase (Cyp7a1) plays a central role in the regulation of bile acid and cholesterol metabolism, and transcription of the gene is controlled by bile acids and hormones acting through a complex interaction with a number of potential steroid-hormone-binding sites. Transcriptional activity of the human CYP7A1 gene promoter transfected into HepG2 cells was decreased in a concentration-dependent manner by co-transfection with an expression vector for peroxisome-proliferator-activated receptor-alpha (PPAR alpha). This effect was augmented by 9-cis-retinoic acid receptor-alpha (RXR alpha) and activators of PPAR alpha to give a maximum inhibition of approx. 80%. The region responsible for this inhibition contained a site known to bind hepatocyte nuclear factor 4 (HNF4), and mutation of this site greatly decreased the effect. Co-expression of HNF4 increased promoter activity and decreased the effect of PPAR alpha. Gel-mobility-shift assays failed to detect any binding of PPAR alpha/RXR alpha dimers to any regions of the promoter containing potential binding sites. Also the hepatic abundance of Cyp7a1 mRNA in mice in which the PPAR alpha gene was disrupted was the same as in normal mice, both during the dark phase, when the animals were feeding, and during the light phase, when mRNA abundance was greatly increased. Cholesterol feeding produced the same increase in hepatic Cyp7a1 mRNA abundance in PPAR alpha-null animals as in normals. It is concluded that, whereas PPAR alpha can affect CYP7A1 gene transcription in vitro through an indirect action, probably by competing for co-factors, this is unlikely to be a major influence on Cyp7a1 activity under normal physiological conditions.

Prolactin as a local growth promoter in patients with breast cancer: GCRI experience

AIMS

The aim of this study was to evaluate the prognostic value of pre-operative prolactin (PRL) in conjunction with established prognosticators, and the risk of disease relapse in patients with early and advanced breast cancer. To confirm the hypothesis that PRL is produced by breast tumours molecular analysis of PRL, using immunohistochemistry, mRNA by RT-PCR and direct sequencing, was performed. Furthermore, presence of prolactin receptors (PRLR) was evaluated by immunohistochemical localization in these patients.

METHODS

In 111 breast cancer patients, pre-operative PRL was determined by an immunoradiometric assay (IRMA) method. Immunohistochemical localization of PRL (IHL-PRL) and PRLR was performed on formalin-fixed, paraffin-embedded tissue sections. Expression of PRL mRNA was carried out by reverse transcriptase polymerase chain reaction (RT-PCR). RT-PCR PRL amplimer was sequenced and compared with human pituitary PRL amplimer.

RESULTS

Fifty-eight per cent (64/111) of the patients had hyperprolactinaemia (PRL520.0 ng/ml). With increasing tumour size, a higher incidence of hyperprolactinaemia was noted which was statistically significant (r=0.34, P=0.0001). In stage III patients, and in node positive patients, the incidence of hyperprolactinaemia was significantly higher compared to their respective counterparts (stage II vs stage III, r=0.37, P=0.00006; node negative vs node positive, r=0.30, P=0.001). Hyperprolactinaemic patients had a significantly higher risk of developing recurrent/metastatic disease and a higher mortality risk as compared to patients with PRL <20.0 ng/ml. The multivariate survival analysis indicated that apart from disease stage, prognosis of patients with pre-operative hyperprolactinaemia was poorer than that of patients with PRL <20.0 ng/ml. Seventy-eight per cent (87/111) of the tumours showed positive immunoreactivity with PRL antibody indicating that PRL, or a similar molecule, is produced ectopically by breast tumours. PRL mRNA expression using RT-PCR confirmed the de novo synthesis of PRL. PRL mRNA expression was seen in 52% (33/63) of tumours. Sequence analysis of the 234 bp PRL amplimer revealed that the sequence was homologous to the sequence of exon 5 of human pituitary PRL mRNA. Furthermore, PRLR were present in 80% of tumours detected by immunohistochemical localization. A significant positive correlation was noted between IHL-PRL and PRLR (r=0.26, P=0.006).

CONCLUSIONS

This multifaceted study of PRL suggests that breast cancer cells produce PRL and that this ectopically produced PRL may act as a major local growth promoter via autocrine and paracrine mechanisms. It may provide new insights into endocrine treatment of breast cancer.

Retinoid-related orphan receptor gamma (RORgamma) is essential for lymphoid organogenesis and controls apoptosis during thymopoiesis

To identify the physiological functions of the retinoid-related orphan receptor gamma (RORgamma), a member of the nuclear receptor superfamily, mice deficient in RORgamma function were generated by targeted disruption. RORgamma(-/-) mice lack peripheral and mesenteric lymph nodes and Peyer's patches, indicating that RORgamma expression is indispensable for lymph node organogenesis. Although the spleen is enlarged, its architecture is normal. The number of peripheral blood CD3(+) and CD4(+) lymphocytes is reduced 6- and 10-fold, respectively, whereas the number of circulating B cells is normal. The thymus of RORgamma(-/-) mice contains 74.4% +/- 8.9% fewer thymocytes than that of wild-type mice. Flow cytometric analysis showed a decrease in the CD4(+)CD8(+) subpopulation. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) staining demonstrated a 4-fold increase in apoptotic cells in the cortex of the thymus of RORgamma(-/-) mice. The latter was supported by the observed increase in annexin V-positive cells. RORgamma(-/-) thymocytes placed in culture exhibit a dramatic increase in the rate of "spontaneous" apoptosis. This increase is largely associated with CD4(+)CD8(+) thymocytes and may, at least in part, be related to the greatly reduced level of expression of the anti-apoptotic gene Bcl-X(L). Flow cytometric analysis demonstrated a 6-fold rise in the percentage of cells in the S phase of the cell cycle among thymocytes from RORgamma(-/-) mice. Our observations indicate that RORgamma is essential for lymphoid organogenesis and plays an important regulatory role in thymopoiesis. Our findings support a model in which RORgamma negatively controls apoptosis in thymocytes.

Expression of the human poliovirus receptor/CD155 gene during development of the central nervous system: implications for the pathogenesis of poliomyelitis

The gene for the human poliovirus receptor (hPVR/CD155) is the founding member of a new family of genes encoding proteins belonging to the immunoglobulin superfamily. To determine whether CD155 is expressed during mammalian development, we have made use of the previously characterized promoter of the CD155 gene and generated mice transgenic for a CD155 promoter-driven beta-galactosidase reporter gene. Expression of the reporter gene in transgenic embryos was observed during midgestation in anterior midline structures of the developing central nervous system and in the neuroretina. During that period, reporter gene expression appeared within the notochord and floor plate along the entire spinal cord reaching into the caudal diencephalon. In addition, transgene expression was observed in axonal projections emanating from retinal ganglion cells forming the optic nerve to reach the future region of the optic chiasm. Analysis of expression of CD155 during human embryonic development confirmed the distribution of reporter gene expression specified by CD155 promoter activity. The anatomical distribution of CD155 promoter activity during embryogenesis matches that of transacting factors previously identified to regulate transcription of the CD155 gene. Expression of CD155 within embryonic structures giving rise to spinal cord anterior horn motor neurons may explain the restrictive host cell tropism of poliovirus for this cellular compartment of the CNS.