RESUMEN

TROP2 is a powerful cancer driver in colorectal cancer cells. Divergent epigenetic regulation mechanisms for the corresponding TACSTD2 gene exist such as miRNAs or DNA methylation. However, the role of TACSTD2 promoter hypermethylation in colorectal cancer has not been investigated yet. In this study, TROP2 expression strongly correlated with promoter methylation in different colorectal tumor cell lines. Treatment with 5-Azacytidine, a DNMT1 inhibitor, led to demethylation of the TACSTD2 promoter accompanied by an increase in TROP2 protein expression. TROP2 expression correlated with promoter methylation in vivo in human colon tumor tissue, thereby verifying promoter methylation as an important factor in the regulation of TROP2 expression in colorectal cancer. When performing a ChIP-Seq analysis in HCT116 and HT29 cells, we found that TACSTD2 promoter demethylation was accompanied by tri-methylation of H3K4. In silico analysis of GSE156613 data set confirmed that a higher binding of histone mark H3K4me3 around the TACSTD2 promoter was found in TACSTD2 high expressing tumors of colon cancer patients compared to the corresponding adjacent tumor tissue. Moreover, the link between TROP2 and the H3K4me3 code was even evident in tumors showing high intratumoral heterogeneity for TROP2 staining. Our data provide novel evidence for promoter demethylation and simultaneous gains of the active histone mark H3K4me3 across CpG-rich sequences, both being complementary mechanisms in the transcriptional regulation of TACSTD2 in colon cancer. The functional consequences of TROP2 loss in colorectal cancer needs to be further investigated.

Asunto(s)

Neoplasias del Colon , Neoplasias Colorrectales , Humanos , Epigénesis Genética , Desmetilación del ADN , Metilación de ADN , Línea Celular Tumoral , Neoplasias del Colon/genética , Regulación Neoplásica de la Expresión Génica , Neoplasias Colorrectales/patología , Islas de CpG , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/metabolismo , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/metabolismo

RESUMEN

After publication of this Article the authors noticed errors in several figures. In Fig. 2b the Gapdh panels are incorrect. The lysates are identical to those used in Fig. 1b, therefore the Gapdh panels should be the same in both figures. In Fig. 3b the Gapdh panels for Ad-Fhit-wt and Ad-Fhit-Y114F are incorrect and have been replaced with scans from original films. In Fig. 4A the Gapdh panels are incorrect. The lysates are identical to those used in Fig. 3b, therefore the Gapdh panels should be the same in both figures. In Fig. 4Bb the Gapdh panels for Fhit siRNA were incorrect and have been replaced with scans from original films. All resupplied figures are provided below. In Fig. 5C several panels are incorrect. The Authors were unable to locate the original films for all of these panels so Fig. 5c has been deleted. The scientific conclusions of this paper have not been affected.

RESUMEN

Pain management during and following disbudding procedures has been studied extensively, though few studies have evaluated wound healing following cautery disbudding in dairy calves. The purpose of this study was to observe wound healing following cautery disbudding with or without treatment using a topical aluminum-based aerosol bandage (ALU) in preweaned dairy calves. Dairy calves were disbudded within the first 3 wk of life using a standard cautery disbudding protocol. The ALU treatment was randomly allocated to the right or left horn bud within each animal. The outcomes measured were lesion score (LS) and wound diameter (WD). The LS was evaluated on a scale of 1 to 3, with LS = 1 representing normal healing without a scab or exudate, LS = 2 having the presence of a scab, and LS = 3 showing the presence of wound exudate. Lesion score and WD were evaluated on a weekly basis following dehorning for 3 wk. A total of 209 animals completed the study. No difference was observed in LS between groups during the first 2 wk postdisbudding, but the proportion of LS = 3 on wk 3 postdisbudding was greater for the control group when compared with ALU (17 vs. 8%, respectively). During wk 1 and 2 postdisbudding, the odds of having delayed healing, or a LS ≥2, were similar for both groups. However, the odds tended to be different at wk 3 postdisbudding with control disbudding sites being 1.42 times more likely to have delayed healing than ALU. In wk 3, WD was 1 mm smaller in the treatment group compared with the control, and treatment decreased diameter over time compared with controls. Overall, once abnormal wound healing was observed, the likelihood of having abnormal wound healing the following week was increased. However, treatment with ALU diminished this effect on delayed healing during the follow-up period. Based on these results, the use of ALU improved wound healing following cautery disbudding of preweaned dairy calves.

Asunto(s)

Aluminio , Cauterización , Aerosoles , Animales , Vendajes , Bovinos , Cicatrización de Heridas

RESUMEN

In this study, loss of expression of the fragile site-encoded Wwox protein was found to contribute to radiation and cisplatin resistance of cells, responses that could be associated with cancer recurrence and poor outcome. WWOX gene deletions occur in a variety of human cancer types, and reduced Wwox protein expression can be detected early during cancer development. We found that Wwox loss is followed by mild chromosome instability in genomes of mouse embryo fibroblast cells from Wwox-knockout mice. Human and mouse cells deficient for Wwox also exhibit significantly enhanced survival of ionizing radiation and bleomycin treatment, agents that induce double-strand breaks (DSBs). Cancer cells that survive radiation recur more rapidly in a xenograft model of irradiated breast cancer cells; Wwox-deficient cells exhibited significantly shorter tumor latencies vs Wwox-expressing cells. This Wwox effect has important consequences in human disease: in a cohort of cancer patients treated with radiation, Wwox deficiency significantly correlated with shorter overall survival times. In examining mechanisms underlying Wwox-dependent survival differences, we found that Wwox-deficient cells exhibit enhanced homology directed repair (HDR) and decreased non-homologous end-joining (NHEJ) repair, suggesting that Wwox contributes to DNA DSB repair pathway choice. Upon silencing of Rad51, a protein critical for HDR, Wwox-deficient cells were resensitized to radiation. We also demonstrated interaction of Wwox with Brca1, a driver of HDR, and show via immunofluorescent detection of repair proteins at ionizing radiation-induced DNA damage foci that Wwox expression suppresses DSB repair at the end-resection step of HDR. We propose a genome caretaker function for WWOX, in which Brca1-Wwox interaction supports NHEJ as the dominant DSB repair pathway in Wwox-sufficient cells. Taken together, the experimental results suggest that reduced Wwox expression, a common occurrence in cancers, dysregulates DSB repair, enhancing efficiency of likely mutagenic repair, and enabling radiation and cisplatin treatment resistance.

Asunto(s)

Proteína BRCA1/metabolismo , Reparación del ADN por Unión de Extremidades , Oxidorreductasas/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Antineoplásicos/farmacología , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Línea Celular , Supervivencia Celular/efectos de la radiación , Cisplatino/farmacología , Resistencia a Medicamentos , Femenino , Células HeLa , Humanos , Ratones , Ratones Noqueados , Ratones Desnudos , Unión Proteica , Dominios Proteicos , Radiación Ionizante , Oxidorreductasa que Contiene Dominios WW

RESUMEN

FHIT, at a constitutively active chromosome fragile site, is often a target of chromosomal aberrations and deletion in a large fraction of human tumors. Inactivation of murine Fhit allelessignificantly increases susceptibility of mice to spontaneous and carcinogen-induced tumorigenesis. In this study, transgenic mice, carrying a human FHIT cDNA under control of the endogenous promoter, were produced to determine the effect of Fhit expression, from a nonfragile cDNA transgene outside the fragile region, on carcinogen-induced tumor susceptibility of wildtype and Fhit heterozygous mice. Mice received sufficient oral doses of N-nitrosomethybenzylamine (NMBA) to cause forestomach tumors in >80% of nontransgenic control mice. Although the level of expression of the FHIT transgene in the recombinant mouse strains was much lower than the level of endogenous Fhit expression, the tumor burden in NMBA-treated male transgenic mice was significantly reduced, while female transgenic mice were not protected. To determine if the difference in protection could be due to differences in epigenetic changes at the transgene loci in male versus female mice, we examined expression, hypermethylation and induced re-expression of FHIT transgenes in male and female mice or cells derived from them. The transgene was methylated in male and female mice and in cell lines established from male and female transgenic kidneys, the FHIT locus was both hypermethylated and deacetylated. It is likely that the FHIT transgene is more tightly silenced in female transgenic mice, leading to a lack of protection from tumor induction.

Asunto(s)

Ácido Anhídrido Hidrolasas/genética , Predisposición Genética a la Enfermedad , Proteínas de Neoplasias/genética , Neoplasias Experimentales/genética , Transgenes , Animales , Secuencia de Bases , Western Blotting , Carcinógenos/toxicidad , Metilación de ADN , Metilasas de Modificación del ADN/antagonistas & inhibidores , Cartilla de ADN , Femenino , Inhibidores de Histona Desacetilasas , Hibridación Fluorescente in Situ , Masculino , Ratones , Ratones Transgénicos , Neoplasias Experimentales/inducido químicamente , Regiones Promotoras Genéticas , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa

RESUMEN

The Fhit tumor suppressor binds and hydrolyses diadenosine polyphosphates and the Fhit-substrate complex has been proposed as a proapoptotic effector, as determined by infection of susceptible cancer cells with adenoviruses carrying wild-type fragile histidine triad (FHIT) or catalytic site mutants. The highly conserved Fhit tyrosine 114 (Y114), within the unstructured loop C-terminal of the catalytic site, can be phosphorylated by Src family tyrosine kinases, although endogenous phospho-Fhit is rarely detected. To explore the importance of Y114 and identify Fhit-mediated signaling events, wild-type and Y114 mutant FHIT-expressing adenoviruses were introduced into two human lung cancer cell lines. Caspase-dependent apoptosis was effectively induced only by wild-type but not Y114 mutant Fhit proteins. By expression profiling of FHIT versus mutant FHIT-infected cells, we found that survivin, an Inhibitor of Apoptosis Protein (IAP) family member, was significantly decreased by wild-type Fhit. In addition, Fhit inhibited activity of Akt, a key effector in the phosphatidylinositol 3-OH kinase (PI3K) pathway; loss of endogenous Fhit expression caused increased Akt activity in vitro and in vivo, and overexpression of constitutively active Akt inhibited Fhit-induced apoptosis. The results indicate that the Fhit Y114 residue plays a critical role in Fhit-induced apoptosis, occurring through inactivation of the PI3K-Akt-survivin signal pathway.

Asunto(s)

Ácido Anhídrido Hidrolasas/genética , Regulación de la Expresión Génica/fisiología , Genes Supresores de Tumor/fisiología , Neoplasias Pulmonares/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Tirosina/metabolismo , Adenoviridae/genética , Western Blotting , Fosfatidilinositol 3-Quinasa Clase I , Citometría de Flujo , Perfilación de la Expresión Génica , Humanos , Proteínas Inhibidoras de la Apoptosis , Neoplasias Pulmonares/genética , Proteínas Asociadas a Microtúbulos/genética , Análisis de Secuencia por Matrices de Oligonucleótidos , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/genética , ARN Interferente Pequeño/farmacología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal , Survivin , Células Tumorales Cultivadas , Tirosina/genética

RESUMEN

To identify functions of the fragile tumour suppressor gene, FHIT, matched pairs of Fhit-negative and -positive human cancer cell clones, and normal cell lines established from Fhit -/- and +/+ mice, were stressed and examined for differences in cell cycle kinetics and survival. A larger fraction of Fhit-negative human cancer cells and murine kidney cells survived treatment with mitomycin C or UVC light compared to matched Fhit-positive cells; approximately 10-fold more colonies of Fhit-deficient cells survived high UVC doses in clonigenic assays. The human cancer cells were synchronised in G1, released into S and treated with UVC or mitomycin C. At 18 h post mitomycin C treatment approximately 6-fold more Fhit-positive than -negative cells had died, and 18 h post UVC treatment 3.5-fold more Fhit-positive cells were dead. Similar results were obtained for the murine -/- cells. After low UVC doses, the rate of DNA synthesis in -/- cells decreased more rapidly and steeply than in +/+ cells, although the Atr-Chk1 pathway appeared intact in both cell types. UVC surviving Fhit -/- cells appear transformed and exhibit >5-fold increased mutation frequency. This increased mutation burden could explain the susceptibility of Fhit-deficient cells in vivo to malignant transformation.

Asunto(s)

Ácido Anhídrido Hidrolasas/fisiología , Apoptosis , Ciclo Celular , Resistencia a Antineoplásicos , Mitomicina/efectos adversos , Proteínas de Neoplasias/fisiología , Tolerancia a Radiación , Neoplasias Gástricas/patología , Ácido Anhídrido Hidrolasas/genética , Animales , Apoptosis/efectos de los fármacos , Apoptosis/efectos de la radiación , Proteínas de la Ataxia Telangiectasia Mutada , Ciclo Celular/efectos de los fármacos , Ciclo Celular/efectos de la radiación , Proteínas de Ciclo Celular/metabolismo , Transformación Celular Neoplásica/efectos de los fármacos , Transformación Celular Neoplásica/efectos de la radiación , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Ensayo de Unidades Formadoras de Colonias , ADN/efectos de los fármacos , ADN/efectos de la radiación , Regulación Neoplásica de la Expresión Génica , Genes Supresores de Tumor , Humanos , Riñón/efectos de los fármacos , Riñón/efectos de la radiación , Cinética , Ratones , Mutación/genética , Proteínas de Neoplasias/genética , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Transducción de Señal , Neoplasias Gástricas/metabolismo , Células Tumorales Cultivadas , Rayos Ultravioleta

RESUMEN

The fragile histidine triad (FHIT) gene is frequently inactivated in various types of tumours. However, the system-wide pathology caused by FHIT inactivation has not been examined in detail. Here we demonstrate that Fhit gene knockout mice develop tumours in the lymphoid tissue, liver, uterus, testis, forestomach and small intestine, together with structural abnormalities in the small intestinal mucosa. These results suggest that Fhit plays important roles in systemic tumour suppression and in the integrity of mucosal structure of the intestines.

Asunto(s)

Ácido Anhídrido Hidrolasas/genética , Genes Supresores de Tumor/fisiología , Neoplasias Intestinales/patología , Linfoma/patología , Proteínas de Neoplasias/genética , Neoplasias Gástricas/patología , Neoplasias Testiculares/patología , Neoplasias Uterinas/patología , Animales , Femenino , Intestino Delgado/anomalías , Intestino Delgado/patología , Masculino , Ratones , Ratones Noqueados , Lesiones Precancerosas/genética , Lesiones Precancerosas/metabolismo , Lesiones Precancerosas/patología

RESUMEN

Common chromosome fragile sites show susceptibility to DNA damage, leading to alterations that contribute to cancer development. The cloning and characterization of fragile sites have demonstrated that fragile sites are associated with genes that relate to tumorigenesis. Identification of the basis of instability at fragile sites and the related genes provides an entree to understanding of important aspects of chromosomal instability, a prominent feature of neoplastic genomes. FHIT/FRA3B and WWOX/FRA16D, the most sensitive common fragile genes in the human genome, function as tumor suppressor genes. The common features of these two common fragile genes are summarized, and suggest clues to understanding the relation between genomic instability and tumor biology.

Asunto(s)

Sitios Frágiles del Cromosoma , Fragilidad Cromosómica/genética , Genes , Animales , Rotura Cromosómica , Deleción Cromosómica , Genes Supresores de Tumor , Humanos , Neoplasias/genética

RESUMEN

The FHIT gene encompassing the most active common human chromosomal fragile region, FRA3B, was discovered in 1996 and proposed as a tumour suppressor gene for important human cancers. Seven years and more than 350 reports later, early questions concerning its tumour suppressor role have been answered. Recent studies on the role of Fhit loss in major types of human cancers report association with high proliferative and low apoptotic indices, node positivity, loss of mismatch repair protein, likelihood of progression and reduced survival.

Asunto(s)

Proteínas de Neoplasias/genética , Neoplasias/genética , Ácido Anhídrido Hidrolasas , Apoptosis , Disparidad de Par Base , División Celular , Progresión de la Enfermedad , Genes Supresores de Tumor , Humanos , Proteínas de Neoplasias/farmacología , Neoplasias/fisiopatología , Sobrevida

Asunto(s)

Cromosomas Humanos Par 3 , Genes Supresores de Tumor , Animales , Carcinógenos/farmacología , Mapeo Cromosómico , Humanos , Pérdida de Heterocigocidad , Ratones , Ratones Noqueados

RESUMEN

CONTEXT: The fragile histidine triad gene (FHIT) encompasses a human common fragile site, FRA3B, that is susceptible to environmental carcinogens. Deletion and inactivation of FHIT have been seen in a number of human premalignant and malignant lesions. OBJECTIVE: To review and evaluate preclinical studies of cancer therapy using the FHIT tumor suppressor gene and related studies involving Fhit protein expression. DATA SOURCES: A MEDLINE search of articles published from 1996 to June 2001 was performed; article reference lists were used to retrieve additional relevant articles. STUDY SELECTION: Immunohistochemical studies of primary tumors or relevant lesions were selected to evaluate Fhit expression in premalignant or malignant stages. Preclinical studies on antitumorigenic or therapeutic introduction of FHIT were reviewed for the effects of exogenous Fhit expression. For the immunohistochemical analyses, 26 studies were included that analyzed at least 15 cases of a single type of tumor. For precancerous lesions, 9 studies were included that analyzed at least 4 cases. For studies of FHIT introduction, 9 published studies were included. DATA EXTRACTION: Using primary data from each of the studies, we assessed the rationale and potential contribution of FHIT cancer therapy. Data was independently abstracted by 2 authors and study quality was assessed by 2 other authors. DATA SYNTHESIS: Overall, 60% (1162/1948 cases) of primary tumors showed absent or markedly reduced Fhit protein expression in cancer cells. Studies of preneoplastic lesions or early-stage cancer showed absence or marked reduction of Fhit protein expression in 0% to 93% of samples (overall, 31% [127/408 cases]). Preclinical studies using 26 cancer-derived cell lines from human lung, head and neck, esophageal, gastric, cervical, pancreatic, and kidney cancers, showed that reintroduction of FHIT resulted in inhibition of in vitro tumor cell growth or of in vivo tumorigenicity in 17 (57%) of 30 cell line experiments. Model systems for human preventive cancer therapy suggested that oral introduction of viral vector-mediated FHIT into Fhit-deficient mice may prevent carcinogen-induced tumor development in some cases. CONCLUSION: These findings show that FHIT gene therapy may potentially be clinically useful for treatment of cancer and also prevention of carcinogen-induced tumor development, suggesting a rationale for further research involving FHIT introduction.

Asunto(s)

Ácido Anhídrido Hidrolasas , Genes Supresores de Tumor , Terapia Genética , Proteínas de Neoplasias/genética , Neoplasias/terapia , Lesiones Precancerosas/terapia , Animales , Estudios de Evaluación como Asunto , Humanos , Inmunohistoquímica , Ratones , Modelos Animales , Proteínas de Neoplasias/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patología , Lesiones Precancerosas/genética , Lesiones Precancerosas/metabolismo , Lesiones Precancerosas/patología , Transfección

RESUMEN

BACKGROUND: A number of studies have shown that the Fhit tumour suppressor protein is abundantly expressed in normal epithelial cells of human organs and that this expression is lost or reduced in the majority of cancers arising in these epithelial tissues. A variety of antiFhit sera have been used but a systematic comparison of the different antisera has not yet been reported. MATERIALS AND METHODS: We compared the Fhit expression pattern in the epithelium of fibrous epuli, oral lichen planus, oral epithelial dysplasia and oral squamous cell carcinomas (OSCC) using three different Fhit antisera. RESULTS: The antigstFhit sera from two sources gave very similar results for all types of oral lesions except for lichen planus and showed that about 60% of OSCCs have lost Fhit expression. CONCLUSION: Although different staining patterns were found for the three antisera, all three could be used for evaluation of Fhit expression in OSCC.

Asunto(s)

Ácido Anhídrido Hidrolasas , Carcinoma de Células Escamosas/metabolismo , Mucosa Bucal/metabolismo , Neoplasias de la Boca/metabolismo , Proteínas de Neoplasias/biosíntesis , Lesiones Precancerosas/metabolismo , Carcinoma de Células Escamosas/patología , Humanos , Sueros Inmunes , Inmunohistoquímica , Liquen Plano Oral/metabolismo , Liquen Plano Oral/patología , Mucosa Bucal/patología , Neoplasias de la Boca/patología , Lesiones Precancerosas/patología

RESUMEN

BACKGROUND: To investigate the possible role of FHIT, a possible tumour suppressor gene, in oral carcinogenesis, we examined 17 oral squamous cell carcinomas (OSCCs) for genetic alterations. MATERIALS AND METHODS: Fresh tissue was obtained during surgery, snap-frozen in liquid nitrogen and stored at -70 degrees C. Nested PCR amplification to examine the integrity of FHIT mRNA was performed on the reverse transcribed complementary DNA obtained from the frozen normal and tumour tissue. Immunohistochemistry was done on formal in-fixed paraffin-embedded tissue protein from the same cases using a polyclonal antiserum against the full length Fhit. RESULTS: Twelve out 17 (71%) OSCCs showed reduced or absent Fhit protein and half of the cases with reduced Fhit protein exhibited aberrant RT-PCR products. CONCLUSION: Immunohistochemical detection of Fhit protein expression in OSCCs is the more sensitive method to determine the status of Fhit in these tumours, in agreement with previous studies of other tumour types.

Asunto(s)

Ácido Anhídrido Hidrolasas , Carcinoma de Células Escamosas/genética , Neoplasias de la Boca/genética , Proteínas de Neoplasias/biosíntesis , ARN Neoplásico/genética , Carcinoma de Células Escamosas/metabolismo , ADN Complementario/genética , Expresión Génica , Humanos , Inmunohistoquímica , Neoplasias de la Boca/metabolismo , Proteínas de Neoplasias/genética , ARN Mensajero/biosíntesis , ARN Mensajero/genética , ARN Neoplásico/biosíntesis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa

RESUMEN

A reciprocal, balanced, constitutional chromosome translocation, t(2;3)(q33;q21), which is associated with familial clear cell renal cancer, has been described and the genomic regions surrounding the 2q and 3q breakpoints have been characterized. Based on the genomic map of the 2q break, EST AI468595 was positioned near the 2q33 translocation and the full-length gene and cDNA were isolated. This 57-kb gene, designated the DIRC1 gene, was disrupted between exons 1 and 2 by the familial translocation. The 1.5-kb mRNA encodes an 11-kDa predicted protein of 104 amino acids. Low-level expression of DIRC1 was detected by reverse transcriptase-polymerase chain reaction amplification in adult placenta, testis, ovary, and prostate and in fetal kidney, spleen, and skeletal muscle. A GFP-Dirc1 fusion protein was expressed in vitro and a polyclonal anti-Dircl peptide serum was prepared. A panel of cancer and cancer-derived cell line DNAs was examined for DIRC1 mutations, but only a rare polymorphism was observed. Two familial tumors showed loss of the derivative 3 chromosome, as observed in a Dutch kindred with t(2;3)associated renal cancers. Mutations in the second DIRC1 allele were not detected. Further studies will be required to determine if disruption of the DIRC1 gene contributed to development of the associated familial clear cell renal cancers.

Asunto(s)

Cromosomas Humanos Par 2 , Cromosomas Humanos Par 3 , Proteínas de Neoplasias/biosíntesis , Proteínas de Neoplasias/genética , Translocación Genética , Células 3T3 , Alelos , Animales , Secuencia de Bases , Carcinoma de Células Renales/genética , Carcinoma de Células Renales/metabolismo , Clonación Molecular , ADN Complementario/metabolismo , Exones , Etiquetas de Secuencia Expresada , Humanos , Immunoblotting , Neoplasias Renales/genética , Neoplasias Renales/metabolismo , Pérdida de Heterocigocidad , Ratones , Datos de Secuencia Molecular , Mutación , Polimorfismo Genético , Polimorfismo Conformacional Retorcido-Simple , ARN Largo no Codificante , Proteínas Recombinantes de Fusión/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Distribución Tisular , Transfección

RESUMEN

Mice carrying one inactivated Fhit allele (Fhit +/- mice) are highly susceptible to tumor induction by N-nitrosomethylbenzylamine, with 100% of Fhit +/- mice exhibiting tumors of the forestomach/squamocolumnar junction vs. 25% of Fhit +/+ controls. In the current study a single N-nitrosomethylbenzylamine dose was administered to Fhit +/+, +/-, and -/- mice to compare carcinogen susceptibility in +/- and -/- Fhit-deficient mice. At 29 weeks after treatment, 7.7% of wild-type mice had tumors. Of the Fhit -/- mice 89.5% exhibited tumors (average 3.3 tumors/mouse) of the forestomach and squamocolumnar junction; half of the -/- mice had medium (2 mm diameter) to large (>2 mm) tumors. Of the Fhit +/- mice 78% exhibited tumors (average 2.4 tumors/mouse) and 22% showed medium to large tumors. Untreated Fhit-deficient mice have been observed for up to 2 years for spontaneous tumors. Fhit +/- mice (average age 21 mo) exhibit an average of 0.94 tumors of different types; Fhit -/- mice (average age 16 mo) also showed an array of tumors (average 0.76 tumor/mouse). The similar spontaneous and induced tumor spectra observed in mice with one or both Fhit alleles inactivated suggests that Fhit may be a one-hit tumor suppressor gene in some tissues.

Asunto(s)

Ácido Anhídrido Hidrolasas , Proteínas de Neoplasias , Neoplasias Experimentales/genética , Proteínas/genética , Animales , Carcinógenos/toxicidad , Dimetilnitrosamina/análogos & derivados , Dimetilnitrosamina/toxicidad , Femenino , Genotipo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neoplasias Experimentales/inducido químicamente , Neoplasias Experimentales/patología , Fenotipo , Neoplasias Gástricas/inducido químicamente , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología

RESUMEN

The fragile histidine triad (FHIT) gene is a tumor suppressor gene that is altered by deletion in a large fraction of human tumors, including pancreatic cancer. To evaluate the potential of FHIT gene therapy, we developed recombinant adenoviral and adenoassociated viral (AAV) FHIT vectors and tested these vectors in vitro and in vivo for activity against human pancreatic cancer cells. Our data show that viral FHIT gene delivery results in apoptosis by activation of the caspase pathway. Furthermore, Fhit overexpression enhances the susceptibility of pancreatic cancer cells to exogenous inducers of apoptosis. In vivo results show that FHIT gene transfer delays tumor growth and prolongs survival in a murine model mimicking human disease.

Asunto(s)

Ácido Anhídrido Hidrolasas , Apoptosis/genética , Proteínas de Neoplasias , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Proteínas/genética , Adenoviridae/genética , Animales , Caspasas/metabolismo , Ciclo Celular/fisiología , División Celular/genética , Fragmentación del ADN , Femenino , Técnicas de Transferencia de Gen , Genes Supresores de Tumor , Terapia Genética , Vectores Genéticos/genética , Humanos , Ratones , Ratones Desnudos , Mitocondrias/fisiología , Neoplasias Pancreáticas/metabolismo , Biosíntesis de Proteínas , Transducción de Señal/fisiología , Transducción Genética , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

Cancers develop and progress via activation of oncogenes and loss of tumor suppressor genes, a progression that can be recapitulated through cross breeding mouse strains harboring genetic mutations. To define the role of RET/PTC3, p53 and Fhit in thyroid carcinogenesis, we intercrossed RET/PTC3 transgenics with p53-/- mice. This new strain, RET/PTC3p53-/-, succumb to rapidly growing and strikingly large multilobed thyroid tumors containing mixtures of both well and poorly differentiated, highly proliferative follicular epithelial cells. Interestingly, transplanted tumors from RET/PTC3p53-/- mice grew in SCID but not syngeneic immunocompetent mice indicating that these advanced tumors were immunogenic. RET/PTC3 protein expression was reduced to undetectable levels in tumors of older mice suggesting that the continued elevated expression of RET/PTC3 may not be necessary for tumor progression. Similarly, expression of Fhit protein was reduced in early tumors and undetected in older tumors irrespective of tumor histopathology. In contrast to RET/PTC3p53-/- mice, RET/PTC3Fhit-/- mice did not develop advanced thyroid carcinomas. These studies support a model of human thyroid cancer whereby thyroid epithelium expresses RET/PTC3 protein at early stages of tumor development, followed by the reduction of RET/PTC3 and loss of p53 function with progressive reduction of Fhit protein expression coincident with malignant progression.

Asunto(s)

Ácido Anhídrido Hidrolasas , Carcinoma/genética , Proteínas de Drosophila , Proteínas de Neoplasias , Oncogenes , Fosfoproteínas Fosfatasas/genética , Proteínas Proto-Oncogénicas/genética , Proteínas Tirosina Quinasas Receptoras/genética , Proteínas de Saccharomyces cerevisiae , Neoplasias de la Tiroides/genética , Proteína p53 Supresora de Tumor/genética , Animales , Antígenos de Diferenciación , Carcinoma/inmunología , Carcinoma/patología , Transformación Celular Neoplásica , Ratones , Ratones SCID , Ratones Transgénicos , Modelos Biológicos , Neoplasias Experimentales , Fosfoproteínas Fosfatasas/aislamiento & purificación , Proteína Fosfatasa 2 , Proteína Fosfatasa 2C , Proteínas/aislamiento & purificación , Proteínas Proto-Oncogénicas/aislamiento & purificación , Proteínas Proto-Oncogénicas c-ret , Proteínas Tirosina Quinasas Receptoras/aislamiento & purificación , Neoplasias de la Tiroides/inmunología , Neoplasias de la Tiroides/patología

RESUMEN

BACKGROUND: Our purpose was to investigate the expression of FHIT (Fragile Histidine Triad) gene product in a series of 110 urinary bladder TCCs, and its eventual relationship with histological grade, clinical stage, recurrences and patients' survival. MATERIALS AND METHODS: We performed immunohistochemistry in archival material of formalin-fixed, paraffin-embedded tissues, using the anti-Fhit antibody and the Streptavidin-biotin peroxidase method. RESULTS: In 30 out of 110 cases (27.27%) Fhit protein was absent whereas in 32 cases (29.08%) it was abnormally expressed. In 48 cases (43.63%) Fhit protein was diffusely expressed in all tumor cells. A statistically highly significant correlation (p < 0.001) was noticed between Fhit protein absence or reduction and clinically advanced tumors. Conversely, abnormal Fhit protein expression was not associated with age, histological grade, tumor size, number of recurrences, and clinical outcome in terms of patients' survival. CONCLUSIONS: These results confirm that FHIT gene inactivation is a late event in urinary bladder carcinogenesis. Fhit protein reduced expression or complete absence correlates with advanced clinical stage of the disease, and does not seem to correlate with tumor recurrences and patient survival.

Asunto(s)

Ácido Anhídrido Hidrolasas , Carcinoma de Células Transicionales/fisiopatología , Regulación Neoplásica de la Expresión Génica , Proteínas de Neoplasias , Proteínas/genética , Neoplasias de la Vejiga Urinaria/fisiopatología , Carcinoma de Células Transicionales/patología , Progresión de la Enfermedad , Humanos , Estadificación de Neoplasias , Neoplasias de la Vejiga Urinaria/patología