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Peripheral dopamine receptors, potential targets for a new class of antihypertensive agents. Part I: Subclassification and functional description.

The dopamine receptors of the peripheral cardiovascular system are not a pharmacologically uniform population. A number of studies indicate that they belong to at least two distinct subtypes for which it is proposed to adopt the name DA1- and DA2-dopamine receptors in an attempt to follow the nomenclature presently in fashion for several vascular receptors. Typical DA1-dopamine receptors are those occurring postjunctionally in the renal and mesenteric arterial beds where their stimulation mediates direct smooth muscle relaxation. Typical DA2-dopamine receptors are those present on postganglionic sympathetic neurons (axonal varicosities and perhaps ganglionic cell bodies) where their excitation leads, under appropriate physiological conditions, to a reduction of the neural release of norepinephrine. The latter effect can manifest itself by a passive fall in vascular resistance and heart rate. Other populations of dopamine receptors not yet well characterized pharmacologically but of theoretical interest as additional potential target sites for cardiovascular drugs might be present on nephrons and in the adrenal cortex. Their stimulation can mediate a natriuretic effect and a reduction of aldosterone release, respectively. The pharmacological evidence favoring the subclassification of cardiovascular dopamine receptors into two distinct subtypes is reviewed. Furthermore, the main agonists and antagonists of these receptors and the complexity of their pharmacological profile are mentioned. Part II of this minireview will be dedicated to the description of the sites and mechanisms of the antihypertensive action of dopamine receptor agonists.

Animals↗

Potential target genes of EMX2 include Odz/Ten-M and other gene families with implications for cortical patterning.

EMX2 and PAX6 are expressed by cortical progenitors and specify area patterning. We used representational difference analysis (RDA) to compare expressed RNAs from wild type and Emx2-/- cortex and identified 41 unique clones. Using secondary screening by in situ hybridization, we selected five genes for further analysis, Cdk4, Cofilin1, Crmp1, ME2, and Odz4, involved in neuronal proliferation, differentiation, migration, and axon guidance. Each exhibits differential expression in wild type cortex. Odz4 is one of four members of a vertebrate gene family homologous to the Drosophila pair-rule patterning gene, Odd Oz (Odz), a transmembrane receptor. We show that Odz genes are expressed in complementary patterns in cortex, as well as in nuclei-specific patterns in thalamus that relates to their area-unique cortical expression. In addition, each of the genes analyzed shows different expression patterns in wild type cortex, Emx2, and Pax6 mutant cortex, consistent with potential roles in area patterning. These findings identify potential targets of EMX2 that might account for its function and the defects in Emx2-/- cortex, and suggest that the Odz family of transmembrane proteins influences cortical area patterning downstream to EMX2 and PAX6.

Animals↗

elt-1, a gene encoding a Caenorhabditis elegans GATA transcription factor, is highly expressed in the germ lines with msp genes as the potential targets.

The Caenorhabditis elegans ELT-1 protein, a homolog of the vertebrate GATA transcription factor family, is a transcription activator that can recognize the GATA motif. We previously showed that the elt-1 mRNA was primarily expressed in C. elegans embryos. To examine whether the elt-1 mRNA in embryos is maternal, paternal or zygotic, Northern blot analysis was performed with RNA isolated from the C. elegans germ-line mutant strains, fem-2 (b245)lf, fem-3 (q20)gf, him-8 (e1489), and glp-4 (bn2). This analysis revealed that the high level of elt-1 mRNA in the C. elegans embryos resulted from either the maternal or the paternal transcription, rather than from the zygotic expression. These results further demonstrated that elt-1 was highly expressed in the germ-line of both sexes. To investigate the possible target genes for the ELT-1 protein in the germ line, the ELT-1 protein was expressed and tested for its binding specificity to the GATA motif that is present in the promoter region of the C. elegans major sperm protein genes. It was found that two conserved cis-elements, AGATCT and AGATAA, in the proximal promoter region of the msp-113 gene provided the best recognition site for ELT-1. Mutational analysis showed that the GATC core sequence was necessary for strong transactivation of the reporter gene, and that the combination of GATC and GATA motif resulted in a stronger transactivation by ELT-1 than either the duplicated GATC or GATA motif. These results suggest that the potential target for the ELT-1 protein in the germ-line may be one of the major sperm protein gene family.

Animals↗

HLA-B27 transgenic mice are susceptible to collagen-induced arthritis: type II collagen as a potential target in human disease.

HLA-B27 is highly linked with a group of human diseases called spondyloarthropathies (SpA). Many of these disorders begin after an infection with an enterobacteria. The symptoms seen in patients with spondyloarthropathies are inflammatory pain in the spine and asymmetrical arthritis of lower limbs. Additional symptoms related to SpA include inflammation in the eyes, bowel, and skin. The autoantigen(s) in SpA are not known. Proteins such as collagen and proteoglycans have been thought to be potent autoantigens in arthritidis including B27-associated human diseases. Type II collagen is a common denominator among eyes and joints, affected tissues in B27-linked diseases. Moreover, a few reports indicated CII specific T cells and antibodies in patients with spondyloarthropathies. We and others have previously described development of spontaneous arthritis and nail disease in HLA-B27 transgenic animals. To determine whether CII may be a target antigen in the B27-linked diseases, B27 + m beta 2 m% (HLA-B27) transgenic mice lacking mouse beta 2m with and without human beta 2m) mice were immunized with type II collagen inside the barrier facility. Male HLA-B27 transgenic mice developed collagen-induced arthritis compared to transgene negative littermates or female counterparts. There was no difference in the incidence of arthritis in HLA-B27 transgenic mice with and without human beta 2m. Our data suggest that beta 2m free heavy chain of HLA-B27 may present soluble antigens such as type II collagen to trigger specific T cells contributing in the development of arthritis. Our data also suggest that CII may be a potential target antigen in the cartilage during the disease process.

Animals↗

Type I methionine aminopeptidase from Saccharomyces cerevisiae is a potential target for antifungal drug screening.

AIM: To screen antifungal drug candidates using in vitro and in vivo assays based on type I methionine aminopeptidase from Saccharomyces cerevisiae (ScMetAP1). METHODS: A colorimetric assay suitable for high throughput screening (HTS) using recombinant ScMetAP1 protein expressed in Escherichia coli was established for antifungal lead discovery. A series of pyridine-2-carboxylic acid derivatives were characterized and a chemical library of 12,800 pure organic compounds was screened with the in vitro ScMetAP1 assay. Active compounds from the in vitro assay were further evaluated by a growth inhibition assay on yeast strain with deletion of ScMetAP1 gene map1 in comparison with the wild-type yeast strain and the yeast strain with deletion of type II enzyme (ScMetAP2) gene map2. RESULTS: Active ScMetAP1 inhibitors were identified from HTS. Some of the pyridine-2-carboxylic acid derivatives (compound 2 and 3) had selective inhibition of the growth of map2 deletion yeast and weak inhibition on wild-type yeast growth, while no inhibition on map1 deletion yeast. CONCLUSION: ScMetAP1 is a novel potential target for developing antifungal drugs. The in vitro and in vivo ScMetAP1 assays can serve as tools in discovering antifungal drug candidates.

Aminopeptidases↗

Beta2-agonist abuse in food producing animals: use of in vitro liver preparations to assess biotransformation and potential target residues for surveillance.

1. The biotransformation of [3H]clenbuterol, [3H]salbutamol, [14C]salmeterol and 7-ethoxycoumarin by bovine liver was investigated by incubation with freshly prepared microsomes, suspension and monolayer cultures of isolated hepatocytes, precision-cut (250 microm) and chopped (600 microm) tissue slices. 2. Radio-HPLC analysis indicated that the saligenin beta2-agonists salmeterol and salbutamol were extensively metabolized by all intact cell preparations. A single major product (SmM1) was evident for salmeterol and two unresolved products for salbutamol (SbM1 and SbM2). Differential enzyme hydrolysis studies with Helix pomatia beta-glucuronidase/aryl sulphatase indicated that the main metabolites were glucuronide conjugates. Consistent with this, analysis of metabolites by liquid chromatography-mass spectrometry showed molecular ions ([M+H]+) at m/z 592 for Sm1 and 416 for both Sb1 and Sb2. 3. Comparable studies with clenbuterol revealed three minor metabolites. Prolonged incubations generated products representing, at maximum, 27% biotransformation. Two of the products have been identified as a glucuronide ([M+H]+, m/z 453) and hydroxyclenbuterol ([M+H]+, m/z 293). 4. These findings indicate that in vitro studies provide simple and cost-effective means of evaluating xenobiotic metabolism, and thus of identifying potential target residues to enable surveillance of use of unlicensed veterinary drugs, or prohibited substances in farm animals.

Adrenergic beta-Agonists↗

Sphingomyelin synthase as a potential target for D609-induced apoptosis in U937 human monocytic leukemia cells.

Tricyclodecan-9-yl-xanthogenate (D609) is a selective tumor cytotoxic agent. However, the mechanisms of action of D609 against tumor cells have not been well established. Using U937 human monocytic leukemia cells, we examined the ability of D609 to inhibit sphingomyelin synthase (SMS), since inhibition of SMS may contribute to D609-induced tumor cell cytotoxicity via modulating the cellular levels of ceramide and diacylglycerol (DAG). The results showed that D609 is capable of inducing U937 cell death by apoptosis in a dose- and time-dependent manner. The induction of U937 cell apoptosis was associated with an inhibition of SMS activity and a significant increase in the intracellular level of ceramide and decrease in that of sphingomyelin (SM) and DAG, which resulted in an elevation of the ratio between ceramide and DAG favoring the induction of apoptosis. In addition, incubation of U937 cells with C(6)-ceramide and/or H7 (a selective PKC inhibitor) reduced U937 cell viability; whereas pretreatment of the cells with a PKC activator, PMA or 1-oleoyl-2-acetylglycerol (OAG), attenuated D609-induced U937 cell apoptosis. These results suggest that SMS is a potential target of D609 and inhibition of SMS may contribute to D609-induced tumor cell death via modulation of the cellular levels of ceramide and DAG.

Antineoplastic Agents↗

Gene expression in midgut carcinoid tumors: potential targets for immunotherapy.

Classical midgut carcinoids are serotonin-secreting tumors derived from enterochromaffin cells in the gut. Metastatic disease represents a therapeutic challenge and immunotherapy implies a novel approach for treatment. In order to define antigens suitable for T-cell therapy with a preferential expression in midgut carcinoid tissue a broad screening of genes with preferential neuroendocrine restriction, genes described as over-expressed in various malignancies, and genes encoding cancer-testis associated antigens was performed. The expression of 32 genes was analyzed by reverse transcription polymerase chain reaction (RT-PCR) in 28 midgut carcinoid specimens, in the cell line BON and in normal tissues. Immunohistochemistry (IHC) was used to evaluate protein expression. Expression is shown of genes that have previously not been observed in midgut carcinoid tumors, such as Survivin and GAGEs. Also the expression is confirmed of genes that encode pivotal proteins in enterochromaffin cells, such as TPH1 and VMAT1, and their tissue-restricted expression is indicated. In addition, gene expression of IA-2 and CDX-2 in normal gastrointestinal (GI) tract and in tumor is shown. Protein expression of TPH, VMAT1, and Survivin was detected in tumor tissue. This study elucidates that TPH1, VMAT1, and Survivin should be further investigated as potential target antigens for T cell-mediated immunotherapy of midgut carcinoids.

Adult↗

Disialoganglioside GD2 and a novel tumor antigen: potential targets for immunotherapy of desmoplastic small round cell tumor.

BACKGROUND: Desmoplastic small round cell tumor (DSRCT) is an aggressive and often misdiagnosed neoplasm of children and young adults. It is chemotherapy-sensitive, yet patients often relapse off therapy because of residual microscopic disease at distant sites: peritoneum, liver, lymph node, and lung. Strategies directed at minimal residual disease (MRD) may be necessary for cure. Monoclonal antibodies selective for cell surface tumor-associated antigens may have utility for diagnosis and therapy of MRD, as recently demonstrated in advanced-stage neuroblastoma (JCO 16: 3053, 1998). We examined DSRCT samples for the expression of two tumor antigens that could serve as possible targets for antibody-based immunotherapeutic approaches. PROCEDURES: Using immunohistochemistry, we studied the expression of two antigens: (1) G(D2) using antibody 3F8 and (2) a novel antigen using antibody 8H9 in a panel of 46 freshly frozen DSRCT. G(D2) is a disialoganglioside, which is widely expressed among neuroectodermal tumors as well as adult sarcomas. 8H9 recognizes a 58 kDa surface antigen expressed among neuroectodermal, mesenchymal, and epithelial tumors with restricted expression on normal tissues. RESULTS: Thirty-two of 46 (70%) tumors were reactive with 3F8, and 44 of 46 (96%) with 8H9. Both G(D2) and the 58 kDa antigen were localized to tumor cell membrane and stroma. In general, immunoreactivity was stronger and more homogeneous with 8H9 than with 3F8. There was no correlation between expression of either antigen or clinical outcome. CONCLUSIONS: G(D2) and the novel tumor antigen recognized by 8H9 are potential targets for immunodiagnosis and antibody-based therapy of DSRCT. Med Pediatr Oncol 2002;39:547-551.

Adolescent↗

The nuclear receptors FXR and LXRalpha: potential targets for the development of drugs affecting lipid metabolism and neoplastic diseases.

The orphan nuclear receptors FXR and LXRalpha have become challenging targets for the discovery of new therapeutic agents. Bile acids and hydroxysterol intermediates are the respective natural ligands of these two structurally and functionally closely related receptors. Both FXR and LXRalpha; are thought to play a major role in the control of cholesterol catabolism by regulating the expression of cholesterol 7alpha-hydroxylase, the rate limiting enzyme of bile acid synthesis. Reverse cholesterol transport might also be affected by FXR and LXR since they control the expression of PLTP and CETP, two proteins involved in the transfer of phospholipid, cholesterol and cholesteryl esters among plasma lipoproteins. A new class of potent synthetic activators of FXR, the 1,1-bisphosphonate esters, has been discovered which up regulate the Intestinal Bile Acid Binding Protein gene (I-BABP) as demonstrated for chenodeoxycholic acid, however there are no known synthetic activators yet identified for LXRalpha. The evaluation of FXR as a potential target for the development of drugs affecting plasma cholesterol can take advantage of the fact that the activators of FXR (farnesol, bile acids and the 1,1-bisphosphonate esters) have been studied in various in vitro and in vivo models. Administration of chenodeoxycholic acid to animals and man did not result in the increase in plasma cholesterol expected from a decrease in cholesterol 7alpha-hydroxylase expression. Like farnesol, the 1,1-bisphosphonate esters increase the rate of degradation of HMGCoA reductase and have the unexpected property of inducing hypocholesterolemia in normal animals. The natural and synthetic FXR agonists trigger differentiation, inhibit cell proliferation and are potent inducers of apoptosis. The 1,1-bisphosphonate ester SR-45023A (Apomine) is presently being developed as an antineoplastic drug.

Amino Acid Sequence↗

Aminopeptidases as potential targets for the control of the Australian sheep blowfly, Lucilia cuprina.

A series of experiments were carried out to investigate the role of proteinase enzymes in the growth of larvae of the sheep blowfly, Lucilia cuprina. First, instar larvae were incubated on an artificial growth media in the presence of various concentrations of inhibitors of all the major proteinase classes. Inhibitors of serine proteinases and aminopeptidases were found to cause significant growth inhibition and in some cases death of the larvae within 24 h, suggesting that these enzymes were the major classes involved in protein digestion in the gut of the insect. A second group of experiments analysed the effects of two inhibitors from the same or different proteinase classes in the growth media. Synergistic inhibition of larval growth was observed with the incorporation of inhibitors of serine proteinases and aminopeptidases. The results suggest that these classes of proteinases are both central to protein digestion in this insect, probably in the gut, and that the inhibition of both types of activity leads to an almost complete blockade of digestion. Testing in vivo gave similar results with infections on sheep skin inhibited by either serine proteinase or aminopeptidase enzyme inhibitors and the combination of both stopped the infection process. The role of aminopeptidases in larval metabolism and as potential targets for blowfly control agents is examined.

Aminopeptidases↗

Identification of potential target genes for Adr1p through characterization of essential nucleotides in UAS1.

Adr1p is a regulatory protein in the yeast Saccharomyces cerevisiae that binds to and activates transcription from two sites in a perfect 22-bp inverted repeat, UAS1, in the ADH2 promoter. Binding requires two C2H2 zinc fingers and a region amino terminal to the fingers. The importance for DNA binding of each position within UAS1 was deduced from two types of assays. Both methods led to an identical consensus sequence containing only four essential base pairs: GG(A/G)G. The preferred sequence, TTGG(A/G)GA, is found in both halves of the inverted repeat. The region of Adr1p amino terminal to the fingers is important for phosphate contacts in the central region of UAS1. However, no base-specific contacts in this portion of UAS1 are important for DNA binding or for ADR1-dependent transcription in vivo. When the central 6 bp were deleted, only a single monomer of Adr1p was able to bind in vitro and activation in vivo was severely reduced. On the basis of these results and previous knowledge about the DNA binding site requirements, including constraints on the spacing and orientation of sites that affect activation in vivo, a consensus binding site for Adr1p was derived. By using this consensus site, potential Adr1p binding sites were located in the promoters of genes known to show ADR1-dependent expression. In addition, this consensus allowed the identification of new potential target genes for Adr1p.

Alcohol Dehydrogenase↗

MMP-10 is overexpressed, proteolytically active, and a potential target for therapeutic intervention in human lung carcinomas.

Matrix metalloproteinase (MMP)-mediated degradation of the extracellular matrix is a major factor for tumor development and expansion. This study analysed MMP-10 protein expression and activity in human lung tumors of various grade, stage, and type to address the relationship between MMP-10 and tumor characteristics and to evaluate MMP-10 as a therapeutic target in non small cell lung carcinoma (NSCLC). Unlike the majority of MMPs, MMP-10 was located in the tumor mass as opposed to tumor stroma. MMP-10 protein was observed at low levels in normal human lung tissues and at significantly higher levels in all types of NSCLC. No correlation was observed between MMP-10 protein expression and tumor type, stage, or lymph node invasion. To discriminate between active and inactive forms of MMP-10 in samples of human NSCLC, we have developed an ex vivo fluorescent assay. Measurable MMP-10 activity was detected in 42 of 50 specimens of lung cancer and only 2 of 10 specimens of histologically normal lung tissue. No relationship was observed between MMP-10 activity levels and clinicopathologic characteristics. Our results suggest that MMP-10 is expressed and active at high levels in human NSCLC compared to normal lung tissues, and, as such, is a potential target for the development of novel therapeutics for lung cancer treatment.

Animals↗

The murine liver is a potential target organ for IL-19, IL-20 and IL-24: Type I Interferons and LPS regulate the expression of IL-20R2.

BACKGROUND/AIMS: The biological functions of the recently discovered IL-10-related cytokines IL-19, IL-20, IL-22, IL-24 and their receptors IL-20R1, IL-20R2 and IL-22R are not clear. Therefore, the expression of these cytokines and their receptors in the hepatic acute phase response to LPS was analysed. Type I interferons have important immunomodulatory functions in bacterial infections. We investigated if they influence release and organ-specific expression of TNF, IL-6 and IL-10 and the responsiveness of liver to IL-10 related cytokines during the reaction to LPS in vivo. METHODS: B6 and congenic IFNAR-/- mice were intraperitoneally injected with 5mg/kg LPS. Systemic release of cytokines was quantified by ELISA. Organ-specific expression of cytokines and their receptors was evaluated by (semi quantitative or quantitative) RT-PCR. RESULTS: The cytokines IL-19, IL-22 and the IL-20R2 receptor subunit are up-regulated by LPS in the liver of normal mice. IFNalpha/beta enhance the secretion and expression of IL-6 and IL-10 during the response to LPS, but also the up-regulation of IL-20R2 expression. CONCLUSIONS: We show that the liver is a potential target for IL-19, IL-20 and IL-24. During an LPS response, IFNalpha/beta influence cytokine secretion and expression and possibly the response to IL-19 and IL-24.

Acute-Phase Proteins↗

The deoxyribonucleoside phosphotransferase of Trichomonas vaginalis. A potential target for anti-trichomonial chemotherapy.

Trichomonas vaginalis, a human protozoan parasite known to lack the capability of synthesizing purine and pyrimidine nucleotides de novo, was found also incapable of converting its ribonucleotides to deoxyribonucleotides. The only apparent means of providing deoxyribonucleotides for DNA synthesis relies on salvaging exogenous deoxyribonucleosides by a deoxyribonucleoside phosphotransferase activity in the T. vaginalis 10(5) g pelletable fraction. The activity, constituted by at least two isozymes I and II, can be solubilized by Triton X-100, has a pH optimum of 5.0-6.0, and recognizes only thymidine, deoxyadenosine, deoxyguanosine, and deoxycytidine as the phosphate acceptor. TMP, dAMP, dGMP, dCMP, dUMP, FdUMP, and p-nitrophenylphosphate can serve as phosphate donors. Enzyme I has been purified 10-fold by DEAE-Sepharose chromatography and Sephacryl 200 filtration, and is totally freed of the acid phosphatase of T. vaginalis. It has an estimated molecular weight of 200,000 and Km values of 2-3 mM for the four deoxyribonucleosides, which act on each other as competitive inhibitors. It also possesses phosphatase activity capable of hydrolyzing p-nitrophenylphosphate with a Michaelis constant of 0.74 mM. The rates of hydrolysis are enhanced by thymidine, which suggests that the latter may be the preferred phosphate acceptor, and Enzyme I may be, thus, more a transferase than a phosphatase. This enzyme could be a potential target for antitrichomonial chemotherapy.

Animals↗

A Drosophila RNA helicase gene, pitchoune, is required for cell growth and proliferation and is a potential target of d-Myc.

This article describes the characterization of a new Drosophila gene that we have called pitchoune (pit) (meaning small in Provence) because mutations in this gene produce larvae that cannot grow beyond the first instar larval stage although they can live as long as 7-10 days. All the tissues are equally affected and the perfectly shaped larvae are indistinguishable from first instar wild-type animals. Analysis of mutant somatic clones suggests a function in cell growth and proliferation, which is supported by the fact that cell proliferation is promoted by pit overexpression. Tagged-Pit, when transfected in S2 cells, localizes mainly to the nucleolus, pointing towards a possible role in ribosome biogenesis and, consequently, in protein biosynthesis. pit encodes a DEAD-box RNA helicase, a family of proteins involved in the control of RNA structure in many cellular processes and its closest homologue is a human DEAD-box RNA helicase, MrDb, whose corresponding gene transcription is directly activated by Myc-Max heterodimers (Grandori, C., Mac, J., Siëbelt, F., Ayer, D. E. and Eisenman, R. N. (1996) EMBO J. 15, 4344-4357). The patterns of expression of d-myc and pit are superimposable. Ectopic expression of myc in the nervous system drives an ectopic expression of pit in this tissue indicating that in Drosophila as well, pit is a potential target of d-Myc. These results suggest that myc might promote cell proliferation by activating genes that are required in protein biosynthesis, thus linking cell growth and cell proliferation.

Amino Acid Sequence↗

Osteopontin is a potential target gene in mouse mammary cancer chemoprevention by Se-methylselenocysteine.

BACKGROUND: Se-methylselenocysteine (MSC) is a naturally occurring organoselenium compound that inhibits mammary tumorigenesis in laboratory animals and in cell culture models. Previously we have documented that MSC inhibits DNA synthesis, total protein kinase C and cyclin-dependent kinase 2 kinase activities, leading to prolonged S-phase arrest and elevation of growth-arrested DNA damage genes, followed by caspase activation and apoptosis in a synchronized TM6 mouse mammary tumor model. The aim of the present study was to examine the efficacy of MSC against TM6 mouse mammary hyperplastic outgrowth (TM6-HOG) and to determine in vivo targets of MSC in this model system. METHODS: Twenty mammary fat pads each from female Balb/c mice transplanted with TM6-HOG and fed with 0.1 ppm selenium and with 3 ppm selenium respectively, were evaluated at 4 and 12 weeks after transplantation for growth spread, proliferative index and caspase-3 activity. Thirteen mice transplanted with TM6-HOG in each selenium group were observed for tumor formation over 23 weeks. Tumors from mice in both groups were compared by cDNA array analysis and data were confirmed by reverse transcription-polymerase chain reaction. To determine the effect of MSC on the expression of the novel target gene and on cell migration, experiments were performed in triplicate. RESULTS: A dietary dose of 3 ppm selenium significantly reduced the growth spread and induced caspase-3 activity in mammary fat pads in comparison with mice fed with the basal diet (0.1 ppm selenium). The extended administration (23 weeks) of 3 ppm selenium in the diet resulted in a tumor incidence of 77% in comparison with 100% tumor incidence in 0.1 ppm selenium-fed animals. The size of TM6 tumors in the supplemented group was smaller (mean 0.69 cm2) than in the mice fed with the basal diet (mean 0.93 cm2). cDNA array analysis showed a reduced expression of osteopontin (OPN) in mammary tumors of mice fed with the 3 ppm selenium diet in comparison with OPN expression in tumors arising in 0.1 ppm selenium-fed mice. A 24-hour treatment of TM6 cells with MSC significantly inhibited their migration and also reduced their OPN expression in comparison with untreated cells. CONCLUSIONS: OPN is a potential target gene in the inhibition of mammary tumorigenesis by selenium.

Animals↗

A new melanoma antigen fatty acid-binding protein 7, involved in proliferation and invasion, is a potential target for immunotherapy and molecular target therapy.

The identification of molecules that are preferentially expressed in melanoma cells and involved in their malignant phenotypes is important for understanding melanoma biology and the development of new diagnostic and therapeutic methods. By comparing the expression profile of a melanoma cell line with those of various normal tissues using GeneChip and by confirming the actual expression of the selected genes by reverse transcription-PCR and Northern and Western blot analyses, fatty acid-binding protein 7 (FABP7), which is frequently expressed in melanomas, was identified. Immunohistochemical examination revealed that FABP7 was expressed in 11 of 15 melanoma tissues. By down-regulating the FABP7 expression with FABP7-specific small interfering RNAs, in vitro cell proliferation and Matrigel invasion were suppressed in two of six melanoma cell lines. Overexpression of FABP7 in a FABP7-negative embryonic kidney cell line 293T by transfecting with the FABP7 cDNA resulted in enhanced cell proliferation and Matrigel invasion, indicating that FABP7 plays a role in the malignant phenotype of some melanoma cell lines. IgG antibodies specific for the phage or bacterial recombinant FABP7 protein were detected in 14 of 25 (56%) or in 8 of 31 (26%) sera from melanoma patients, respectively, but not in sera from healthy individuals, indicating that FABP7 is an immunogenic antigen in melanoma patients. These results showed that FABP7 is frequently expressed in melanoma, may be involved in cell proliferation and invasion, and may be a potential target for development of diagnostic and therapeutic methods.

Antibody Specificity↗