RESUMEN
Trop-2 is a calcium signal transducer that is associated with transformed cell growth in experimental systems. However, its role in human cancer remains essentially unknown. In this study, we profiled Trop-2 expression in normal human tissues at the mRNA and protein levels. We then systematically compared Trop-2 mRNA and protein levels in tumours with their tissues of origin. We find that Trop-2 expression is invariably upregulated in tumours, regardless of baseline expression in normal tissues, which suggests a corresponding selective advantage. Thus, we investigated the outcome of Trop-2 upregulation on tumour growth. Overexpression of wild-type Trop-2 was shown to be necessary and sufficient to drive cancer growth in a widely invariant manner across cell type and species. Upregulation of Trop-2 was shown to quantitatively stimulate tumour growth, as proportional to expression levels in vivo, and tumour cell growth was abrogated by somatic knockdown of Trop-2 expression. On the other hand, we found no evidence of tumour-associated TROP2 mutations, nor of TROP2 induction of oncogenic transformation per se. Our data support a model where above-baseline expression of wild-type Trop-2 is a key driver of human cancer growth.
Asunto(s)
Antígenos de Neoplasias/metabolismo , Moléculas de Adhesión Celular/metabolismo , Neoplasias/metabolismo , Neoplasias/patología , Animales , Antígenos de Neoplasias/genética , Señalización del Calcio , Moléculas de Adhesión Celular/genética , Ciclo Celular , Línea Celular Tumoral , Proliferación Celular , Transformación Celular Neoplásica/genética , Femenino , Humanos , Células MCF-7 , Ratones , Ratones Desnudos , Mutación , Interferencia de ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Interferente Pequeño , Transducción de Señal , Regulación hacia ArribaRESUMEN
Melanoma is one of the most aggressive types of cancer and resection of the tumour prior to dissemination of tumour cells is still the most effective treatment. Therefore, early diagnosis of melanocytic lesions is important and identification of novel (molecular) markers would be helpful to improve diagnosis. Moreover, better understanding of molecular targets involved in melanocytic tumorigenesis could possibly lead to development of novel interventions. In this study, we used a custom made oligonucleotide array containing 298 genes that were previously found to be differentially expressed in human melanoma cell lines 1F6 (rarely metastasising) and Mel57 (frequently metastasising). We determined differential gene expression in human common nevocellular nevus and melanoma metastasis lesions. By performing nine dye-swap array experiments, using individual as well as pooled melanocytic lesions, a constant differential expression could be detected for 25 genes in eight out of nine or nine out of nine array analyses. For at least nine of these genes, namely THBD, FABP7, H2AFJ, RRAGD, MYADM, HR, CKS2, NCK2 and GDF15, the differential expression found by array analyses could be verified by semiquantitative and/or real-time quantitative RT-PCR. The genes that we identified to be differentially expressed during melanoma progression could be potent targets for diagnostic, prognostic and/or therapeutic interventions.
Asunto(s)
Expresión Génica/genética , Melanoma/genética , Neoplasias Cutáneas/genética , Línea Celular Tumoral , Perfilación de la Expresión Génica , Humanos , Análisis de Secuencia por Matrices de Oligonucleótidos , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
The increasing incidence of melanoma and the lack of effective treatment, with the exception of tumour excision before the onset of the metastatic phase, make it important to identify genes that may function as new molecular markers for diagnosis and/or prognosis or as new targets for therapy. Recently, a new technique using high density oligonucleotide arrays has been developed to simultaneously screen for the expression of thousands of genes. We used this technique to compare the mRNA expression patterns of two human melanoma cell lines with different metastatic behaviour. Eight differentially expressed genes, namely apolipoprotein CII, tyrosinase-related protein 1, transforming growth factor-beta superfamily, subtilisin-like protein, elongation factor 1 alpha2, alpha2-macroglobulin, human cell division cycle 10 and serine/threonine protein kinase (DYRK1A), were selected to validate the array results by Northern blotting and reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, a reliable correlation between differential expression of these genes in the melanoma cell lines and in fresh lesions of melanocytic tumour progression was demonstrated by RT-PCR analysis. Altogether, our data indicate that high density oligonucleotide arrays are a valuable and reliable tool to screen for differentially expressed genes, and that our study may be considered a basic step in the characterization of genes that are involved in the (malignant) progression of melanoma.
Asunto(s)
Melanoma/genética , Melanoma/patología , Análisis de Secuencia por Matrices de Oligonucleótidos , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Northern Blotting , ADN Complementario/metabolismo , Regulación hacia Abajo , Humanos , Metástasis de la Neoplasia , ARN Complementario/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células Tumorales Cultivadas , Regulación hacia ArribaRESUMEN
In order to define genes which mediate liver tropism of colon cancer metastasis we have compared the transcriptional profile of 5600 full-length genes using the Affymetrix HuGene FL array technology of the non-metastatic colon cancer cell lines KM12C and the two metastatic cell lines, KM12SM and KM12L4A, which are derived from KM12C. We present data on genes which are up- and downregulated in the metastatic cell line and those which are selectively upregulated in one of the metastatic cell lines. We have sub-grouped the deregulated genes into different categories, such as immune response, modulation of transcription, enzymes, cell cycle/apoptosis, interferon- and tumor necrosis factor-regulated genes, tumor antigens and transmembrane receptors, intracellular signaling, cytoskeleton and extracellular matrix associated proteins, 'others' and genes of unknown function.
Asunto(s)
Neoplasias del Colon/genética , Neoplasias Hepáticas Experimentales/genética , Neoplasias Hepáticas Experimentales/secundario , Animales , Neoplasias del Colon/metabolismo , Neoplasias del Colon/patología , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Hepáticas Experimentales/metabolismo , Ratones , Ratones Desnudos , Transcripción Genética , Células Tumorales Cultivadas , Regulación hacia ArribaRESUMEN
Vaccination-based therapy of melanoma has so far mainly focused on monovalent approaches using either melanoma differentiation antigens or cancer/testis antigens. To study the complementarity of expression from these two families of antigens recognized by T-cells, we screened 47 metastatic lesions of cutaneous melanoma for the expression of three melanoma differentiation antigens and eight cancer/testis antigens using reverse transcription-polymerase chain reaction (RT-PCR). The melanoma differentiation antigens were expressed in a somewhat higher percentage of lesions (94% positive for at least one marker) than the cancer/testis antigens (91% positive for at least one marker). Nearly all the melanoma metastases (98%) expressed at least one of the markers tested. One melanoma metastasis was negative for all the markers. Two out of 47 lesions did not express any of the three differentiation markers but expressed one or more of the cancer/testis antigens, indicating some additional potential for these antigens compared with the melanoma differentiation antigens. Therefore, we conclude that polyvalent immunotherapy using multiple epitopes from both families of antigens might increase the eligibility of melanoma patients and the efficacy of the treatment.
Asunto(s)
Antígenos de Neoplasias/genética , Diferenciación Celular/genética , Melanoma/genética , Melanoma/secundario , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Testículo/inmunología , Antígenos de Neoplasias/inmunología , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/inmunología , Diferenciación Celular/inmunología , Perfilación de la Expresión Génica , Humanos , Inmunohistoquímica , Masculino , Melanoma/patología , Melanoma/terapia , Metástasis de la Neoplasia/genética , Metástasis de la Neoplasia/inmunología , Metástasis de la Neoplasia/patología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Urokinase (uPA) has the striking ability to cleave its receptor, uPAR, thereby inactivating the binding potential of this molecule. Here we demonstrate that the glycosylphosphatidylinositol (GPI) anchor of uPAR, which is attached to the third domain, is an important determinant in governing this reaction, even though the actual cleavage occurs between the first and second domains. Purified full-length GPI-anchored uPAR (GPI-uPAR) proved much more susceptible to uPA-mediated cleavage than recombinant truncated soluble uPAR (suPAR), which lacks the glycolipid anchor. This was not a general difference in proteolytic susceptibility since GPI-uPAR and suPAR were cleaved with equal efficiency by plasmin. Since the amino acid sequences of GPI-uPAR and suPAR are identical except for the C-terminal truncation, the different cleavage patterns suggest that the two uPAR variants differ in the conformation or the flexibility of the linker region between domains 1 and 2. This was supported by the fact that an antibody to the peptide AVTYSRSRYLE, amino acids 84-94 in the linker region, recognizes GPI-uPAR but not suPAR. This difference in the linker region is thus caused by a difference in a remote hydrophobic region. In accordance with this model, when the hydrophobic lipid moiety was removed from the glycolipid anchor by phospholipase C, low concentrations of uPA could no longer cleave the modified GPI-uPAR and the reactivity to the peptide antibody was greatly decreased. Naturally occurring suPAR, purified from plasma, was found to have a similar resistance to uPA cleavage as phospholipase C-treated GPI-uPAR and recombinant suPAR.
Asunto(s)
Glicosilfosfatidilinositoles/metabolismo , Receptores de Superficie Celular/metabolismo , Activador de Plasminógeno de Tipo Uroquinasa/metabolismo , Animales , Células CHO , Cromatografía de Afinidad , Cricetinae , Humanos , Cinética , Receptores de Superficie Celular/aislamiento & purificación , Receptores del Activador de Plasminógeno Tipo Uroquinasa , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Transfección , Células U937RESUMEN
In order to identify genes associated with the metastatic phenotype we have compared the expression pattern of 6800 genes in a metastatic (NMCL-1) versus a non-metastatic (530) human melanoma cell line making use of DNA microarrays. The differentially expressed genes identified are involved in control of transcription, regulation of the cell-cycle, proteolysis, cell adhesion, immune response and signaling. A remarkable feature of the system under investigation is the consistent down-regulation of MHC-related and cell adhesion mediating genes in the metastatic cell line.
Asunto(s)
Melanoma/genética , Melanoma/metabolismo , Melanoma/patología , Metástasis de la Neoplasia , Transcripción Genética , Animales , Northern Blotting , Regulación hacia Abajo , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Ratones Endogámicos BALB C , Trasplante de Neoplasias , Análisis de Secuencia por Matrices de Oligonucleótidos , Fenotipo , ARN Mensajero/metabolismo , Células Tumorales Cultivadas , Regulación hacia ArribaRESUMEN
Cell lines 4A4 and 2C5 are the respective metastatic and non-metastatic variants of the human mammary carcinoma cell line MDA-MB-435 in the nude mouse system. We compared the transcriptional profile of approximately 5000 full-length genies using the Affymetrix HuGene FL Array technology. We have shown that the metastatic phenotype is mediated by different functional categories of genes, e.g. genes involved in immune response, genes responsible for tumor antigens, genes involved in migration and invasion, genes involved in mediating signal transduction, genes responsible for transcription factors, genes involved in phospholipid signaling, genes involved in modulation of extracellular matrix and cytoskeleton, genes with a cell-type specific mode of expression and genes which do not fit into the subclasses as defined above. Our results suggest an important role of Autocrine Motility Factor (AMF) as a mediator of metastasis in this system.
Asunto(s)
Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Metástasis de la Neoplasia , Transcripción Genética , Animales , Northern Blotting , Línea Celular , Regulación hacia Abajo , Femenino , Humanos , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Análisis de Secuencia por Matrices de Oligonucleótidos , Fenotipo , ARN Mensajero/metabolismo , Transducción de Señal , Células Tumorales Cultivadas , Regulación hacia ArribaRESUMEN
We have identified two estrogen regulated gene products in the E(2) growth inhibited human breast cancer xenograft, T61; one showing 100% homology to the human BAC clone RP11-112E16, the other 100% homology to the human CPR3/DNJ3 gene. Verification by Northern blot analyses showed an up-regulation of the BAC clone RP11-112E16 and the CPR3/DNJ3 mRNAs upon E(2) treatment. Treatment of T61 tumors with tamoxifen, leading to static tumor growth, also increased the expression of the BAC clone RP11-112E16 and the CPR3/DNJ3 mRNAs. A similar association between growth inhibition and BAC clone RP11-112E16 and CPR3/DNJ3 mRNA induction was observed in MCF-7 cells treated with ICI 182.780. In MCF-7 cells, treatment with E(2) resulted in growth stimulation concomitant with a decrease in the BAC clone RP11-112E16 and CPR3/DNJ3 mRNA expression. Treatment with a combination of E(2) and ICI 182.780 abolished the anti-estrogen induced increase in BAC clone RP11-112E16 and CPR3/DNJ3 mRNA expression, indicating that regulation of the gene products is mediated through the ER. The association between growth inhibition and BAC clone RP11-112E16 or CPR3/DNJ3 mRNA expression was supported by high expression of both gene products in brain tissue. Further investigations are ongoing to clarify the biological function of these two gene products.
Asunto(s)
Neoplasias de la Mama/patología , Estrógenos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Oncogenes/efectos de los fármacos , Animales , Neoplasias de la Mama/genética , División Celular/efectos de los fármacos , División Celular/genética , Femenino , Perfilación de la Expresión Génica , Proteínas del Choque Térmico HSP40 , Proteínas de Choque Térmico/efectos de los fármacos , Proteínas de Choque Térmico/genética , Humanos , Ratones , Ratones Desnudos , Trasplante de Neoplasias , ARN Mensajero/efectos de los fármacos , ARN Mensajero/metabolismo , Tamoxifeno/farmacología , Trasplante Heterólogo , Células Tumorales CultivadasRESUMEN
We have recently described a new member of the PMP22/gas3 family of plasma membrane proteins referred to as THW. This gene is located on chromosome 6q and preliminary data have indicated a possible tumor suppressor gene function. We have therefore investigated LOH for gene THW in a panel of cancer cell lines and in a series of primary human melanomas as well as in melanoma metastases. We have detected LOH for gene THW in cell lines derived from melanoma, breast, pancreas, cervical, prostate and colon carcinoma with different prevalence, whereas the ovary carcinoma cell lines (n = 3) were negative. For melanomas we found a prevalence of LOH for gene THW of 10-20% in primary tumors, whereas in melanoma metastases we found a score of 50%. These data and the fact that the recently identified murine homologue PERP of gene THW mediates cell death in murine fibroblasts support the possible tumor suppressor function of gene THW.
Asunto(s)
Genes Supresores de Tumor , Pérdida de Heterocigocidad , Melanoma/genética , Proteínas de la Membrana/genética , Receptores de Superficie Celular/genética , Secuencia de Aminoácidos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Metástasis de la Neoplasia , Homología de Secuencia de Aminoácido , Células Tumorales CultivadasRESUMEN
Activated leukocyte cell adhesion molecule (ALCAM/CD166), a member of the immunoglobulin superfamily with five extracellular immunoglobulin-like domains, facilitates heterophilic (ALCAM-CD6) and homophilic (ALCAM-ALCAM) cell-cell interactions. While expressed in a wide variety of tissues and cells, ALCAM is restricted to subsets of cells usually involved in dynamic growth and/or migration processes. A structure-function analysis, using two monoclonal anti-ALCAM antibodies and a series of amino-terminally deleted ALCAM constructs, revealed that homophilic cell adhesion depended on ligand binding mediated by the membrane-distal amino-terminal immunoglobulin domain and on avidity controlled by ALCAM clustering at the cell surface involving membrane-proximal immunoglobulin domains. Co-expression of a transmembrane ALCAM deletion mutant, which lacks the ligand binding domain, and endogenous wild-type ALCAM inhibited homophilic cell-cell interactions by interference with ALCAM avidity, while homophilic, soluble ligand binding remained unaltered. The extracellular structures of ALCAM thus provide two structurally and functionally distinguishable modules, one involved in ligand binding and the other in avidity. Functionality of both modules is required for stable homophilic ALCAM-ALCAM cell-cell adhesion.
Asunto(s)
Molécula de Adhesión Celular del Leucocito Activado/metabolismo , Comunicación Celular , Adhesión Celular , Línea Celular , Humanos , LigandosRESUMEN
The plasminogen (Plg)/plasminogen activator (PA) system plays a key role in cancer progression, presumably via mediating extracellular matrix degradation and tumor cell migration. Consequently, urokinase-type PA (uPA)/plasmin antagonists are currently being developed for suppression of tumor growth and angiogenesis. Paradoxically, however, high levels of PA inhibitor 1 (PAI-1) are predictive of a poor prognosis for survival of patients with cancer. We demonstrated previously that PAI-1 promoted tumor angiogenesis, but by an unresolved mechanism. We anticipated that PAI-1 facilitated endothelial cell migration via its known interaction with vitronectin (VN) and integrins. However, using adenoviral gene transfer of PAI-1 mutants, we observed that PAI-1 promoted tumor angiogenesis, not by interacting with VN, but rather by inhibiting proteolytic activity, suggesting that excessive plasmin proteolysis prevents assembly of tumor vessels. Single deficiency of uPA, tissue-type PA (tPA), uPA receptor, or VN, as well as combined deficiencies of uPA and tPA did not impair tumor angiogenesis, whereas lack of Plg reduced it. Overall, these data indicate that plasmin proteolysis, even though essential, must be tightly controlled during tumor angiogenesis, probably to allow vessel stabilization and maturation. These data provide insights into the clinical paradox whereby PAI-1 promotes tumor progression and warrant against the uncontrolled use of uPA/plasmin antagonists as tumor angiogenesis inhibitors.
Asunto(s)
Inhibidores de la Angiogénesis/farmacología , Endopeptidasas/metabolismo , Neoplasias Experimentales/tratamiento farmacológico , Neovascularización Patológica/tratamiento farmacológico , Inhibidor 1 de Activador Plasminogénico/farmacología , Vitronectina/metabolismo , Animales , Endotelio Vascular/efectos de los fármacos , Fibrinolisina/metabolismo , Queratinocitos/patología , Ratones , Ratones Mutantes , Neoplasias de los Músculos/irrigación sanguínea , Invasividad Neoplásica , Neoplasias Experimentales/irrigación sanguínea , Neovascularización Patológica/etiología , Inhibidor 1 de Activador Plasminogénico/metabolismo , Unión Proteica , Vitronectina/genéticaRESUMEN
The proto-oncogene c-myc (myc) encodes a transcription factor (Myc) that promotes growth, proliferation and apoptosis. Myc has been suggested to induce these effects by induction/repression of downstream genes. Here we report the identification of potential Myc target genes in a human B cell line that grows and proliferates depending on conditional myc expression. Oligonucleotide microarrays were applied to identify downstream genes of Myc at the level of cytoplasmic mRNA. In addition, we identified potential Myc target genes in nuclear run-on experiments by changes in their transcription rate. The identified genes belong to gene classes whose products are involved in amino acid/protein synthesis, lipid metabolism, protein turnover/folding, nucleotide/DNA synthesis, transport, nucleolus function/RNA binding, transcription and splicing, oxidative stress and signal transduction. The identified targets support our current view that myc acts as a master gene for growth control and increases transcription of a large variety of genes.
Asunto(s)
Linfocitos B/metabolismo , Genes myc/genética , Transcripción Genética , Linfocitos B/patología , Northern Blotting , Linfoma de Burkitt/genética , Linfoma de Burkitt/patología , Técnicas de Cultivo de Célula , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/genética , Marcación de Gen , Humanos , Cinética , Análisis de Secuencia por Matrices de Oligonucleótidos , Proto-Oncogenes Mas , Activación Transcripcional/genética , Transfección , Células Tumorales CultivadasRESUMEN
In order to identify genes associated with metastasis of ductal pancreatic adenocarcinoma we investigated pancreatic tumor cell lines derived from an orthotopic pancreatic tumor model in SCID mice. Transcriptional profiling (Affymetrix Gene Chip Technology) was performed with cell lines derived from the primary tumor and metastatic lesions such as mesentery, liver and lungs. We scored for genes commonly deregulated in the cell lines derived from the metastatic lesions. Of 7070 genes investigated, 59 (0.83%) were found to be deregulated in the cell lines derived from the metastatic lesions. We grouped these genes into different categories such as transcription, translation, cytoskeleton, cell adhesion, chromosome instability, tumor suppressor genes, enzymes and "others". The most remarkable features of the system are the up-regulation of high mobility group protein HMG-I (Y), twenty-one ribosomal proteins, GAPDH and the laminin receptor in the cell lines derived from the metastatic lesions, whereas tumor suppressor genes such as maspin and RB1 were down-regulated. Inhibition or reconstitution of the activity of these targets are an emerging strategy for inhibition of metastasis in this system.
Asunto(s)
Adenocarcinoma/genética , Adenocarcinoma/secundario , Neoplasias Pancreáticas/genética , Adenocarcinoma/patología , Animales , Femenino , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/secundario , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/secundario , Masculino , Mesenterio/patología , Ratones , Ratones SCID , Trasplante de Neoplasias , Neoplasias Pancreáticas/patología , Neoplasias Peritoneales/genética , Neoplasias Peritoneales/patología , Transcripción Genética , Trasplante Heterólogo , Células Tumorales CultivadasRESUMEN
We have determined the genomic structure of the candidate tumor suppressor gene DICE1 (DDX26). The DICE1 gene colocalizes with microsatellite marker D13S284 telomeric to the RB1 gene in chromosomal region 13q14.3. The DICE1 gene encodes 18 exons that are preceded by a GC-rich promoter region. CpG sites flanking a predicted TATA box were found to be hypermethylated in tumor cells that exhibited decreased DICE1 expression. This suggests tumor-specific transcriptional silencing of the DICE1 gene may occur. Aberrantly spliced products were detected in two of three DICE1 expressing cell lines. The predicted DICE1 amino acid sequence is evolutionarily conserved in mouse, fruit fly (D. melanogaster), and nematode (C. elegans). A DEAD box characteristic of ATP-dependent helicases is the predominant motif found in DICE1 and its mouse and fruit fly homologues. Motifs other than the DEAD box are reminiscent of members of the helicase superfamily II but there is considerable variation from the typical DEAD box helicases. Expression of DICE1 green fluorescent fusion protein showed a preferential localization of DICE1 in the nucleus. This suggests that DICE1 is involved in nuclear processes such as DNA repair, transcription, or RNA splicing.
Asunto(s)
Evolución Biológica , Cromosomas Humanos Par 13 , Genes Supresores de Tumor , Neoplasias Pulmonares/genética , ARN Helicasas , Proteínas Supresoras de Tumor/genética , Animales , Secuencia de Bases , Mapeo Cromosómico , Cromosomas Artificiales de Levadura , Metilación de ADN , Cartilla de ADN , Humanos , Hibridación Fluorescente in Situ , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas , Proteínas de Unión al ARN , Proteínas Ribosómicas , Células Tumorales CultivadasRESUMEN
In order to identify genes associated with metastasis of mammary carcinoma, we compared the transcriptional profile (Affymetrix chip technology) of two cell lines derived from primary mammary carcinoma, three cell lines derived from bone marrow micrometastasis, a cell line derived from a lymph node metastasis as well as a cell line derived from malignant ascites. We found that 11 genes (0.16%) were up-regulated in all five cell lines derived from metastasis and 32 genes (0.45%) were up-regulated in four of these cell lines. Sixteen genes (0.23%) were down-regulated in the five metastatic cell lines, while 24 genes (0.34%) were down-regulated in four of the metastatic cell lines. The usefulness of our system for the identification of genes associated with metastasis of mammary carcinoma is demonstrated by the identification of genes which have already been implicated in metastasis of mammary carcinoma. This suggests that further evaluation of identified de-regulated genes, which until now have not been seen in context with metastasis of mammary carcinoma, should be undertaken.
Asunto(s)
Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Neoplasias de la Médula Ósea/genética , Neoplasias de la Médula Ósea/secundario , Neoplasias de la Mama/metabolismo , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Metástasis Linfática , Metástasis de la Neoplasia , Transcripción Genética , Células Tumorales Cultivadas , Regulación hacia ArribaRESUMEN
Differential Display between metastasizing and non-metastasizing human melanoma cell lines NMCL-1 and 530 led to the identification of a putative transmembrane receptor, designated as THW, which is down-regulated in the metastasizing cell line. THW is composed of 193 aa, exhibits four putative transmembrane domains and does not reveal any homology to other proteins. Down-regulation of THW is correlated with metastatic capacity of melanoma cell lines. THW was down-regulated in mammary carcinoma cell lines compared with cell lines derived from non-malignant mammary epithelium, in pancreas cell lines derived from metastases compared with a cell line derived from a primary tumor and in several tumor tissues compared with normal tissues. The function of THW as a tumor suppressor is emphasized by the location of the THW gene on chromosome 6q. LOH for this region has been reported in malignant melanoma and prostate, pancreas, uterine and mammary carcinomas.
Asunto(s)
Genes Supresores de Tumor , Melanoma/genética , Proteínas de la Membrana/genética , Receptores de Superficie Celular/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , ADN Complementario , Regulación hacia Abajo , Regulación Neoplásica de la Expresión Génica , Células HeLa , Humanos , Proteínas de la Membrana/metabolismo , Ratones , Datos de Secuencia Molecular , Receptores de Superficie Celular/metabolismo , Células Tumorales CultivadasRESUMEN
The role of epigenetic modifications due to deregulated acetylation of nucleosomes with respect to its role in progression and etiology of human cancer is discussed. Among the mediators of these phenomena are the histone deacetylases, a class of enzymes consisting of at least two subfamilies with a total of at least 7 members in mammals. Depending on the cell-type, inhibition of HDACs in cancer cells can lead to transcriptional activation and silencing of about 2% of human genes, cell-cycle arrest and induction of apoptosis and differentiation in vitro and in vivo. This paper discusses several inhibitors of HDACs primarily derived from natural sources, their physiological consequences in different in vitro and in vivo cancer-related systems, their stage of preclinical and clinical development as well as their potential as antineoplastic agents. It is of paramount importance to elucidate the molecular mechanisms resulting in cell-cycle arrest, apoptosis or differentiation after inhibition of HDACs and to investigate the physiological function of the different HDAC isoenzymes and their deregulation in human cancers in order to devise optimized therapeutic intervention in cancer patients.
Asunto(s)
Depsipéptidos , Inhibidores Enzimáticos/farmacología , Inhibidores de Histona Desacetilasas , Histonas/metabolismo , Neoplasias/enzimología , Péptidos Cíclicos , Péptidos , Acetilación , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Inhibidores Enzimáticos/uso terapéutico , Histona Desacetilasas/metabolismo , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismoRESUMEN
In order to identify genes associated with distinct stages of mammary carcinoma we have investigated the transcriptional profile of normal mammary gland epithelial cells, cell lines derived from primary tumors, from bone marrow micrometastases and from ascites fluid. mRNA's for ribosomal protein L41 and URIM (Up-Regulated In Metastasis) were consistently increased in all cells derived from metastatic lesions. mRNA for human secreted frizzled-related protein (hsFRP) was found to be dramatically down-regulated in all mammary tumor cells compared to non-transformed mammary gland epithelial cells. mRNA for Human Hypoxia Related Factor--2 (HRF-2) and a transcript including the human mitochondrial control region were significantly overexpressed in the cell lines derived from primary tumors and ascites fluid. A new gene, referred to as PKW, was only expressed in one of the primary tumor cell lines, the one derived from a medullary carcinoma. The small and the large transcript which are derived by differential splicing encode potential proteins comprising 95 aa and 130 aa, sharing 88 aa at the N-terminus. The IEP's suggest a nuclear localization of the proteins. Surprisingly mRNA for the new gene was detected only in the salivary gland, but not in other adult human tissues and a restricted panel of embryonic tissues. The same holds true for a panel of human tumor cell lines and cell lines derived from ductal mammary carcinoma. RT-PCR revealed expression of PKW in 4 out of 11 breast carcinomas.
Asunto(s)
Neoplasias de la Mama/genética , Oncogenes , Secuencia de Aminoácidos , Secuencia de Bases , Mama/metabolismo , Femenino , Humanos , Datos de Secuencia Molecular , ARN Mensajero/análisis , Transcripción Genética , Células Tumorales CultivadasRESUMEN
The recent demonstration that bone sialoprotein (BSP) is expressed in osteotropic cancers suggests that this bone matrix protein might be implicated in the preferential seed and growth of metastatic cells in bone. High expression of BSP in breast and prostate primary carcinomas is associated with progression and bone metastases development. The exact mechanisms by which BSP may favor bone metastases formation are not clearly established yet. Although BSP expression has been detected in breast, prostate, lung, thyroid, and neuroblastoma primary tumors, no information regarding its expression in metastases is available to date. In this study, we have examined BSP expression in 15 bone and 39 visceral metastatic lesions harvested from 8 breast cancer patients and 7 prostate cancer patients who died of disseminated disease. We were able to retrieve the primary lesions from 5 of the 8 breast cancer patients as well as from all 7 prostate cancer patients. All the primary breast tumor patients and 5 of the 7 primary prostate cancer patients expressed a detectable level of BSP. Bone metastases from all 8 breast cancer patients and from 5 out of 7 prostate cancer patients exhibited detectable levels of the protein. Metastatic cells in close contact with bone trabeculae usually were highly positive for BSP. BSP also was detected in secondary lesions developed at visceral sites including liver, thyroid, lung, and adrenal glands. However, BSP expression was significantly lower in visceral metastases than in skeletal ones (Mann-Whitney test, p < 0.05). Our data represent the first demonstration of an increased expression of BSP in bone metastases compared with nonskeletal metastases in human breast and prostate cancers and add weight to the body of evidence attributing a significant role to this protein in the genesis of bone metastases.