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1.
J Cancer Res Clin Oncol ; 145(9): 2241-2250, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31342168

RESUMO

PURPOSE: The tripartite motif (TRIM)16 acts as a tumour suppressor in both squamous cell carcinoma (SCC) and melanoma. TRIM16 is known to be secreted by keratinocytes, but no studies have been reported yet to assess the relationship between TRIM16 keratinocyte expression and melanoma development. METHODS: To study the role of TRIM16 in skin cancer development, we developed a keratinocyte TRIM16-specific knockout mouse model, and used the classical two-stage skin carcinogenesis challenge method, to assess the loss of keratinocyte TRIM16 on both papilloma, SCC and melanoma development in the skin after topical carcinogen treatment. RESULTS: Heterozygous, but not homozygous, TRIM16 knockout mice exhibited an accelerated development of skin papillomas and melanomas, larger melanoma lesions and an increased potential for lymph node metastasis. CONCLUSION: This study provides the first evidence that keratinocyte loss of the putative melanoma tumour suppressor protein, TRIM16, enhances melanomagenesis. Our data also suggest that TRIM16 expression in keratinocytes is involved in cross talk between keratinocytes and melanocytes, and has a role in melanoma tumorigenesis.


Assuntos
Proteínas de Transporte/genética , Queratinócitos/metabolismo , Perda de Heterozigosidade/fisiologia , Linfonodos/metabolismo , Melanócitos/metabolismo , Melanoma/genética , Neoplasias Cutâneas/genética , Animais , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Proteínas de Transporte/metabolismo , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Células Cultivadas , Regulação Neoplásica da Expressão Gênica , Queratinócitos/patologia , Linfonodos/patologia , Metástase Linfática , Melanócitos/patologia , Melanoma/metabolismo , Melanoma/patologia , Camundongos , Camundongos Knockout , Pele/metabolismo , Pele/patologia , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia
2.
Cell Stem Cell ; 20(5): 609-620.e6, 2017 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-28343984

RESUMO

Organ fitness depends on appropriate maintenance of stem cell populations, and aberrations in functional stem cell numbers are associated with malignancies and aging. Symmetrical division is the best characterized mechanism of stem cell replacement, but other mechanisms could also be deployed, particularly in situations of high stress. Here, we show that after severe depletion, intestinal stem cells (ISCs) in the Drosophila midgut are replaced by spindle-independent ploidy reduction of cells in the enterocyte lineage through a process known as amitosis. Amitosis is also induced by the functional loss of ISCs coupled with tissue demand and in aging flies, underscoring the generality of this mechanism. However, we also found that random homologous chromosome segregation during ploidy reduction can expose deleterious mutations through loss of heterozygosity. Together, our results highlight amitosis as an unappreciated mechanism for restoring stem cell homeostasis, but one with some associated risk in animals carrying mutations.


Assuntos
Intestinos/citologia , Poliploidia , Células-Tronco/citologia , Animais , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Drosophila , Enterócitos/citologia , Feminino , Perda de Heterozigosidade/genética , Perda de Heterozigosidade/fisiologia , Mutação/genética
3.
EBioMedicine ; 9: 120-129, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27333041

RESUMO

The evolution of pediatric solid tumors is poorly understood. There is conflicting evidence of intra-tumor genetic homogeneity vs. heterogeneity (ITGH) in a small number of studies in pediatric solid tumors. A number of copy number aberrations (CNA) are proposed as prognostic biomarkers to stratify patients, for example 1q+ in Wilms tumor (WT); current clinical trials use only one sample per tumor to profile this genetic biomarker. We multisampled 20 WT cases and assessed genome-wide allele-specific CNA and loss of heterozygosity, and inferred tumor evolution, using Illumina CytoSNP12v2.1 arrays, a custom analysis pipeline, and the MEDICC algorithm. We found remarkable diversity of ITGH and evolutionary trajectories in WT. 1q+ is heterogeneous in the majority of tumors with this change, with variable evolutionary timing. We estimate that at least three samples per tumor are needed to detect >95% of cases with 1q+. In contrast, somatic 11p15 LOH is uniformly an early event in WT development. We find evidence of two separate tumor origins in unilateral disease with divergent histology, and in bilateral WT. We also show subclonal changes related to differential response to chemotherapy. Rational trial design to include biomarkers in risk stratification requires tumor multisampling and reliable delineation of ITGH and tumor evolution.


Assuntos
Neoplasias Renais/patologia , Perda de Heterozigosidade/fisiologia , Tumor de Wilms/patologia , Alelos , Biomarcadores Tumorais/genética , Pré-Escolar , Cromossomos Humanos Par 11 , Evolução Clonal , Feminino , Dosagem de Genes , Genoma , Humanos , Lactente , Neoplasias Renais/diagnóstico por imagem , Neoplasias Renais/genética , Imagem por Ressonância Magnética , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Tumor de Wilms/diagnóstico por imagem , Tumor de Wilms/genética
4.
Exp Biol Med (Maywood) ; 240(3): 305-14, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25681467

RESUMO

WWOX gene is located in FRA16D, the highly affected chromosomal fragile site. Its tumor suppressor activity has been proposed on a basis of numerous genomic alterations reported in chromosome 16q23.3-24.1 locus. WWOX is affected in many cancers, showing as high as 80% loss of heterozygosity in breast tumors. Unlike most tumor suppressors impairing of both alleles of WWOX is very rare. Despite cellular and animal models information on a WWOX role in cancer tissue is limited and sometimes confusing. This review summarizes information on WWOX in human tumors.


Assuntos
Neoplasias/genética , Neoplasias/fisiopatologia , Oxirredutases/genética , Oxirredutases/fisiologia , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/fisiologia , Alelos , Neoplasias da Mama/genética , Neoplasias da Mama/fisiopatologia , Feminino , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/fisiopatologia , Perda de Heterozigosidade/genética , Perda de Heterozigosidade/fisiologia , Masculino , Mutação/genética , Mutação/fisiologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/fisiopatologia , Oxidorredutase com Domínios WW
5.
Exp Eye Res ; 128: 83-91, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25261604

RESUMO

There is an ongoing controversy regarding the role of WDR36 sequence variants in the pathogenesis of primary open-angle glaucoma (POAG). WDR36 is a nucleolar protein involved in the maturation of 18S rRNA. The function of WDR36 is essential as homozygous Wdr36-deficient mouse embryos die before reaching the blastocyst stage. Here we provide a detailed analysis of the phenotype of heterozygous Wdr36-deficient mice. Loss of one Wdr36 allele causes a substantial reduction in the expression of Wdr36 mRNA. In the eyes of Wdr36(+/-) animals, the structure of the tissues involved in aqueous humor circulation and of the optic nerve head are not different from that of control littermates. In addition, one-year-old Wdr36(+/-) animals do not differ from wild-type animals with regards to intraocular pressure and number of optic nerve axons. The susceptibility of retinal ganglion cells to excitotoxic damage induced by NMDA is similar in Wdr36(+/-) and wild-type animals. Moreover, the amount of optic nerve axonal damage induced by high IOP is not different between Wdr36(+/-) and wild-type mice. Transgenic overexpression of mutated Del605-607 Wdr36 in Wdr36(+/-) animals does not cause changes in the number of optic nerve axons or susceptibility to excitotoxic damage. In addition, analysis of 18S rRNA maturation in Del605-607 Wdr36(+/-) or Wdr36(+/-) mice does not show obvious differences in rRNA processing or in the amounts of precursor forms when compared to wild-type animals. Our data obtained in Wdr36(+/-) mice do not support the assumption of a causative role for WDR36 in the pathogenesis of POAG.


Assuntos
Proteínas do Olho/genética , Regulação da Expressão Gênica/fisiologia , Glaucoma de Ângulo Aberto/genética , Perda de Heterozigosidade/fisiologia , Alelos , Animais , Axônios/patologia , Northern Blotting , Modelos Animais de Doenças , Glaucoma de Ângulo Aberto/patologia , Pressão Intraocular , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , N-Metilaspartato/toxicidade , Doenças do Nervo Óptico/genética , Doenças do Nervo Óptico/patologia , Fenótipo , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Células Ganglionares da Retina/efeitos dos fármacos , Células Ganglionares da Retina/patologia , Fatores de Risco , Tonometria Ocular
6.
Endocrinology ; 155(10): 4043-53, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25060364

RESUMO

The known genetic causes of idiopathic hypogonadotropic hypogonadism (IHH) are often associated with the loss of GnRH neurons, leading to the disruption of the hypothalamic pituitary gonadal axis and subfertility. The majority of IHH cases have unknown origins and likely arise from compound mutations in more than one gene. Here we identify the homeodomain transcription factor ventral anterior homeobox1 (Vax1) as a potential genetic contributor to polygenic IHH. Although otherwise healthy, male and female Vax1 heterozygous (HET) mice are subfertile, indicating dosage sensitivity for the Vax1 allele. Although Vax1 mRNA is expressed in the pituitary, hypothalamus, and testis, we did not detect Vax1 mRNA in the sperm, ovary, or isolated pituitary gonadotropes. Whereas Vax1 HET females produced normal numbers of superovulated oocytes, corpora lutea numbers were reduced along with a slight increase in circulating basal LH and estrogen. The subfertility originated in the hypothalamus in which kisspeptin and GnRH transcripts were altered along with a substantial reduction of GnRH neuron number. Although the pituitary responded normally to a GnRH challenge, diestrus females had reduced LHß and FSHß in diestrus. Furthermore, Vax1 HET males had reduced GnRH mRNA and neuron numbers, whereas the pituitary had normal transcript levels and response to GnRH. Interestingly, the Vax1 HET males had an 88% reduction of motile sperm. Taken together, our data suggest that Vax1 HET subfertility originates in the hypothalamus by disrupting the hypothalamic-pituitary-gonadal axis. In addition, male subfertility may also be due to an unknown effect of Vax1 in the testis.


Assuntos
Proteínas de Homeodomínio/genética , Infertilidade Feminina/genética , Infertilidade/genética , Neuropeptídeos/genética , Animais , Animais Recém-Nascidos , Feminino , Deleção de Genes , Gônadas/fisiologia , Sistema Hipotálamo-Hipofisário/fisiologia , Infertilidade/fisiopatologia , Tamanho da Ninhada de Vivíparos/genética , Perda de Heterozigosidade/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Gravidez
7.
Proc Natl Acad Sci U S A ; 111(19): 7006-11, 2014 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-24778235

RESUMO

p53 is a well-known tumor suppressor that is mutated in over 50% of human cancers. These mutations were shown to exhibit gain of oncogenic function compared with the deletion of the gene. Additionally, p53 has fundamental roles in differentiation and development; nevertheless, mutant p53 mice are viable and develop malignant tumors only on adulthood. We set out to reveal the mechanisms by which embryos are protected from mutant p53-induced transformation using ES cells (ESCs) that express a conformational mutant of p53. We found that, despite harboring mutant p53, the ESCs remain pluripotent and benign and have relatively normal karyotype compared with ESCs knocked out for p53. Additionally, using high-content RNA sequencing, we show that p53 is transcriptionally active in response to DNA damage in mutant ESCs and elevates p53 target genes, such as p21 and btg2. We also show that the conformation of mutant p53 protein in ESCs is stabilized to a WT conformation. Through MS-based interactome analyses, we identified a network of proteins, including the CCT complex, USP7, Aurora kinase, Nedd4, and Trim24, that bind mutant p53 and may shift its conformation to a WT form. We propose this conformational shift as a novel mechanism of maintenance of genomic integrity, despite p53 mutation. Harnessing the ability of these protein interactors to transform the oncogenic mutant p53 to the tumor suppressor WT form can be the basis for future development of p53-targeted cancer therapy.


Assuntos
Transformação Celular Neoplásica/genética , Células-Tronco Embrionárias/citologia , Síndrome de Li-Fraumeni/genética , Proteína Supressora de Tumor p53/química , Proteína Supressora de Tumor p53/genética , Adenocarcinoma , Animais , Neoplasias da Mama , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células , Desenvolvimento Embrionário/genética , Células-Tronco Embrionárias/fisiologia , Proteínas de Homeodomínio/genética , Humanos , Síndrome de Li-Fraumeni/metabolismo , Perda de Heterozigosidade/fisiologia , Camundongos , Camundongos Knockout , Proteína Homeobox Nanog , Conformação Proteica , Proteômica , Proteína Supressora de Tumor p53/metabolismo
8.
Proc Natl Acad Sci U S A ; 110(40): 16067-72, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-24043837

RESUMO

DNA damage alone or DNA replication fork arrest at damaged sites may induce DNA double-strand breaks and initiate homologous recombination. This event can result in a crossover with a homologous chromosome, causing loss of heterozygosity along the chromosome. It is known that Srs2 acts as an antirecombinase at the replication fork: it is recruited by the SUMO (a small ubiquitin-related modifier)-conjugated DNA-polymerase sliding clamp (PCNA) and interferes with Rad51/Rad52-mediated homologous recombination. Here, we report that Srs2 promotes another type of homologous recombination that produces noncrossover products only, in collaboration with PCNA and Rad51. Srs2 proteins lacking the Rad51-binding domain, PCNA-SUMO-binding motifs, or ATP hydrolysis-dependent DNA helicase activity reduce this noncrossover recombination. However, the removal of either the Rad51-binding domain or the PCNA-binding motif strongly increases crossovers. Srs2 gene mutations are epistatic to mutations in the PCNA modification-related genes encoding PCNA, Siz1 (a SUMO ligase) and Rad6 (a ubiquitin-conjugating protein). Knocking out RAD51 blocked this recombination but enhanced nonhomologous end-joining. We hypothesize that, during DNA double-strand break repair, Srs2 mediates collaboration between the Rad51 nucleofilament and PCNA-SUMO and directs the heteroduplex intermediate to DNA synthesis in a moving bubble. This Rad51/Rad52/Srs2/PCNA-mediated noncrossover pathway avoids both interchromosomal crossover and imprecise end-joining, two potential paths leading to loss of heterozygosity, and contributes to genome maintenance and human health.


Assuntos
Quebras de DNA de Cadeia Dupla , DNA Helicases/genética , Recombinação Homóloga/fisiologia , Perda de Heterozigosidade/fisiologia , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/enzimologia , Primers do DNA/genética , Técnicas de Inativação de Genes , Mutagênese Sítio-Dirigida , Especificidade da Espécie
9.
Cancer Res ; 72(24): 6425-34, 2012 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-23071067

RESUMO

Second malignant neoplasms (SMN) are therapy-induced malignancies and a growing problem in cancer survivors, particularly survivors of childhood cancers. The lack of experimental models of SMNs has limited understanding of their pathogenesis. It is currently not possible to predict or prevent this devastating late complication. Individuals with neurofibromatosis I (NF1) are at increased risk of developing therapy-induced cancers for unclear reasons. To model SMNs, we replicated clinical radiotherapy and delivered fractionated abdominal irradiation to Nf1(+/-) and wild-type mice. Similar to irradiated cancer survivors, irradiated wild-type and Nf1(+/-) mice developed diverse in-field malignancies. In Nf1(+/-) mice, fractionated irradiation promoted both classical NF1-associated malignancies and malignancies unassociated with the NF1 syndrome but typical of SMNs. Nf1 heterozygosity potentiated the mutagenic effects of irradiation, as evidenced by the significantly reduced survival after irradiation and tumor development that was often characterized by synchronous primary tumors. Interestingly, diverse radiation-induced tumors arising in wild-type and Nf1(+/-) mice shared a genetic signature characterized by monoallelic loss of Nf1 and the adjacent Trp53 allele. These findings implicate Nf1 loss as mediating tumorigenesis in a broad range of cell types and organs extending beyond the classical NF1 tumor histologies. Examining clinical SMN samples, we found LOH of NF1 in SMNs from non-NF1 patients. Nf1 heterozygosity confers broad susceptibility to genotoxin-induced tumorigenesis, and this paradigm serves as an experimental platform for future studies of SMNs.


Assuntos
Genes da Neurofibromatose 1/fisiologia , Perda de Heterozigosidade/fisiologia , Metástase Neoplásica/genética , Neoplasias Induzidas por Radiação/genética , Neoplasias/genética , Animais , Modelos Animais de Doenças , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Biológicos , Metástase Neoplásica/patologia , Neoplasias/etiologia , Neoplasias/patologia , Proteína Supressora de Tumor p53/genética , Irradiação Corporal Total
10.
PLoS One ; 7(10): e45606, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23110045

RESUMO

Cholangiocarcinoma (CCA) is a highly lethal malignant tumor arising from the biliary tract epithelium. Interleukin-6 (IL-6) is a major mediator of inflammation and contributor to carcinogenesis within the biliary tree. Previous studies suggested that enforced IL-6 contributes to cholangiocarcinogenesis through hypermethylation of several genes implicated in CCA. However, the precise mechanisms of IL-6 effects in CCA remain unclear. We now demonstrate that microRNA (miR)-370 is underexpressed in a large cohort of human CCA vs. normal liver tissues. In addition, we show that IL-6 induces a time-dependent silencing of miR-370. In addition, demethylation of CCA cells results in upregulation of miR-370. Furthermore, we demonstrate that miR-370 is imprinted, and that the Intergenic Differentially Methylated Region (IG-DMR) responsible for imprinting regulation of this genomic locus is hypermethylated in response to IL-6 treatment. In addition, the IG-DMR is hypermethylated in human CCA specimens compared to normal matched controls, in the same location as the IL-6 induced hypermethylation. Finally, miR-370 was found to regulate WNT10B in luciferase as well as western blotting experiments. Our data indicate that the paternal allele of miR-370 is normally silenced through genomic imprinting and that the overexpression of IL-6 in CCA effectively suppresses the expression of miR-370 from the maternal allele, lending support to the theory that miR-370 silencing in human CCA follows a classic two-hit mechanism.


Assuntos
Colangiocarcinoma/genética , Interleucina-6/farmacologia , Perda de Heterozigosidade/fisiologia , MicroRNAs/genética , Animais , Western Blotting , Linhagem Celular Tumoral , Colangiocarcinoma/metabolismo , Metilação de DNA/genética , Humanos , Técnicas In Vitro , Perda de Heterozigosidade/genética , Camundongos , MicroRNAs/antagonistas & inibidores , Reação em Cadeia da Polimerase Via Transcriptase Reversa
11.
Proc Natl Acad Sci U S A ; 109(35): 14007-12, 2012 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-22893683

RESUMO

The role of NF-κB activation in tumor initiation has not been thoroughly investigated. We generated Ikkß(EE)(IEC) transgenic mice expressing constitutively active IκB kinase ß (IKKß) in intestinal epithelial cells (IECs). Despite absence of destructive colonic inflammation, Ikkß(EE)(IEC) mice developed intestinal tumors after a long latency. However, when crossed to mice with IEC-specific allelic deletion of the adenomatous polyposis coli (Apc) tumor suppressor locus, Ikkß(EE)(IEC) mice exhibited more ß-catenin(+) early lesions and visible small intestinal and colonic tumors relative to Apc(+/ΔIEC) mice, and their survival was severely compromised. IEC of Ikkß(EE)(IEC) mice expressed high amounts of inducible nitric oxide synthase (iNOS) and elevated DNA damage markers and contained more oxidative DNA lesions. Treatment of Ikkß(EE)(IEC)/Apc(+/ΔIEC) mice with an iNOS inhibitor decreased DNA damage markers and reduced early ß-catenin(+) lesions and tumor load. The results suggest that persistent NF-κB activation in IEC may accelerate loss of heterozygocity by enhancing nitrosative DNA damage.


Assuntos
Proteína da Polipose Adenomatosa do Colo/metabolismo , Neoplasias Colorretais/metabolismo , Quinase I-kappa B/genética , Quinase I-kappa B/metabolismo , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Animais , Colite/metabolismo , Colite/patologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/imunologia , Neoplasias Colorretais/patologia , Dano ao DNA/fisiologia , Células Epiteliais/metabolismo , Feminino , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Perda de Heterozigosidade/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Espécies Reativas de Nitrogênio/metabolismo , Células-Tronco/citologia , beta Catenina/metabolismo
12.
Leuk Res ; 36(8): 1035-40, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22640496

RESUMO

Genetic changes in T-ALL are classified into type A abnormalities leading to arrest at a specific stage of T-cell differentiation and type B abnormalities that target cellular processes including cell cycle regulation. Mutations and deletion of a BCL11B haploinsuffiecient tumor suppressor allele have been found in 10-16% of T-ALL subgroups. Analysis of Bcl11b(KO/+) mice revealed impaired T-cell differentiation at two different stages and attenuation of γ-ray induced cell-cycle arrest at S/G2/M phase in immature CD8 single positive cells. Hence, those phenotypes provided by loss of a Bcl11b allele favor that Bcl11b mutation belongs to type B abnormalities.


Assuntos
Ciclo Celular/genética , Diferenciação Celular/genética , Leucemia/genética , Proteínas Repressoras/genética , Timócitos/fisiologia , Proteínas Supressoras de Tumor/genética , Alelos , Animais , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Deleção de Genes , Leucemia/metabolismo , Leucemia/patologia , Perda de Heterozigosidade/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Fenótipo , Proteínas Repressoras/metabolismo , Proteínas Repressoras/fisiologia , Timócitos/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/fisiologia
13.
Mol Cancer Res ; 10(1): 40-51, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22064654

RESUMO

Extracellular superoxide dismutase (EcSOD) is an important superoxide scavenger in the lung in which its loss, sequence variation, or abnormal expression contributes to lung diseases; however, the role of EcSOD in lung cancer has yet to be studied. We hypothesized that EcSOD loss could affect malignant progression in lung, and could be either genetic or epigenetic in nature. To test this, we analyzed EcSOD expression, gene copy number, promoter methylation, and chromatin accessibility in normal lung and carcinoma cells. We found that normal airway epithelial cells expressed abundant EcSOD and had an unmethylated promoter, whereas EcSOD-negative lung cancer cells displayed aberrant promoter hypermethylation and decreased chromatin accessibility. 5-aza-dC induced EcSOD suggesting that cytosine methylation was causal, in part, to silencing. In 48/50 lung tumors, EcSOD mRNA was significantly lower as early as stage I, and the EcSOD promoter was hypermethylated in 8/10 (80%) adenocarcinomas compared with 0/5 normal lung samples. In addition, 20% of the tumors showed loss of heterozygosity (LOH) of EcSOD. Reexpression of EcSOD attenuated the malignant phenotype of lung carcinoma cells by significantly decreasing invasion and survival. Finally, EcSOD decreased heparanase and syndecan-1 mRNAs in part by reducing NF-κB. By contrast, MnSOD and CuZnSOD showed no significant changes in lung tumors and had no effect on heparanase expression. Taken together, the loss of EcSOD expression is unique among the superoxide dismutases in lung cancer and is the result of EcSOD promoter methylation and LOH, suggesting that its early loss may contribute to ECM remodeling and malignant progression.


Assuntos
Adenocarcinoma/patologia , Matriz Extracelular/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/patologia , Superóxido Dismutase/genética , Superóxido Dismutase/fisiologia , Adenocarcinoma/genética , Células Cultivadas , Metilação de DNA/genética , Metilação de DNA/fisiologia , Epigênese Genética/fisiologia , Transição Epitelial-Mesenquimal/genética , Transição Epitelial-Mesenquimal/fisiologia , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Matriz Extracelular/fisiologia , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/fisiologia , Inativação Gênica/fisiologia , Homeostase/genética , Humanos , Perda de Heterozigosidade/fisiologia , Neoplasias Pulmonares/genética , Invasividade Neoplásica , Fenótipo , Regiões Promotoras Genéticas , Regulação para Cima/genética
14.
Blood ; 118(18): 4935-45, 2011 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-21908433

RESUMO

Clinical evidence has shown that FLT3 internal tandem duplication (ITD) mutation confers poor prognosis in acute myeloid leukemia. Loss of the FLT3 wild-type (WT) allele is associated with even worse prognosis. We have previously reported that heterozygous FLT3(wt/ITD) "knockin" mice develop a slowly fatal myeloproliferative neoplasm (MPN). To study the roles of the WT FLT3 and ITD alleles in the development of MPNs, we generated FLT3/ITD homozygous (FLT3(ITD/ITD)) and hemizygous (FLT3(-/ITD)) mice. FLT3(-/ITD) mice, with the loss of WT allele, display a more severe MPN, as evidenced by even larger spleen, higher white blood cell counts, and shorter survival, compared with FLT3(wt/ITD) mice. Reintroduction of the WT FLT3 allele into FLT3(-/ITD) BM slowed the progression of MPN in recipient mice. FLT3(ITD/ITD) mice had an even severe MPN compared with the FLT3(-/ITD) and FLT3(wt/ITD) mice. Spontaneous leukemia developed in a small fraction of the FLT3(ITD/ITD) mice but was never observed in the FLT3(-/ITD) and FLT3(wt/ITD) mice. Our results suggest that loss of the WT allele contributes to the development of a more severe phenotype. Thus, the WT FLT3 allele seemingly functions as a tumor suppressor, attenuating the function of the FLT3/ITD allele in leukemia harboring FLT3/ITD mutations.


Assuntos
Proliferação de Células , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Células Mieloides/fisiologia , Tirosina Quinase 3 Semelhante a fms/genética , Alelos , Animais , Progressão da Doença , Técnicas de Introdução de Genes , Genes Supressores de Tumor/fisiologia , Perda de Heterozigosidade/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células Mieloides/metabolismo , Invasividade Neoplásica , Sequências de Repetição em Tandem/genética , Sequências de Repetição em Tandem/fisiologia , Tirosina Quinase 3 Semelhante a fms/química , Tirosina Quinase 3 Semelhante a fms/metabolismo , Tirosina Quinase 3 Semelhante a fms/fisiologia
15.
Blood ; 118(13): 3613-21, 2011 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-21813452

RESUMO

Acquisition of homozygous activating growth factor receptor mutations might accelerate cancer progression through a simple gene-dosage effect. Internal tandem duplications (ITDs) of FLT3 occur in approximately 25% cases of acute myeloid leukemia and induce ligand-independent constitutive signaling. Homozygous FLT3-ITDs confer an adverse prognosis and are frequently detected at relapse. Using a mouse knockin model of Flt3-internal tandem duplication (Flt3-ITD)-induced myeloproliferation, we herein demonstrate that the enhanced myeloid phenotype and expansion of granulocyte-monocyte and primitive Lin(-)Sca1(+)c-Kit(+) progenitors in Flt3-ITD homozygous mice can in part be mediated through the loss of the second wild-type allele. Further, whereas autocrine FLT3 ligand production has been implicated in FLT3-ITD myeloid malignancies and resistance to FLT3 inhibitors, we demonstrate here that the mouse Flt3(ITD/ITD) myeloid phenotype is FLT3 ligand-independent.


Assuntos
Dosagem de Genes/fisiologia , Duplicação Gênica/fisiologia , Perda de Heterozigosidade/fisiologia , Proteínas de Membrana/genética , Transtornos Mieloproliferativos/genética , Tirosina Quinase 3 Semelhante a fms/fisiologia , Alelos , Animais , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Células da Medula Óssea/fisiologia , Proliferação de Células , Células Cultivadas , Técnicas de Introdução de Genes , Perda de Heterozigosidade/genética , Masculino , Proteínas de Membrana/metabolismo , Proteínas de Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fenótipo , Sequências de Repetição em Tandem/genética , Sequências de Repetição em Tandem/fisiologia , Tirosina Quinase 3 Semelhante a fms/metabolismo
16.
Semin Oncol ; 38(4): 511-20, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21810510

RESUMO

Approximately one third of patients diagnosed with early-stage colon cancer will present with lymph node involvement (stage III) and about one quarter with transmural bowel wall invasion but negative lymph nodes (stage II). Adjuvant chemotherapy targets micrometastatic disease to improve disease-free (DFS) and overall survival (OS). While beneficial for stage III patients, the role of adjuvant chemotherapy is unestablished in stage II disease. This likely relates to the improved outcome of these patients, and the difficulties in developing studies with sufficient power to document benefit in this patient population. However, recent investigation also suggests that molecular differences may exist between stage II and III cancers and within stage II patients. Validated pathologic prognostic markers are useful at identifying stage II patients at high risk for recurrence for whom the benefit from adjuvant chemotherapy may be greater. Such high-risk features include higher T stage (T4 v T3), suboptimal lymph node retrieval, presence of lymphovascular invasion, bowel obstruction, or bowel perforation, and poorly differentiated histology. However, for the majority of patients who do not carry any of these adverse features and are classified as "average-risk" stage II patients, the benefit of adjuvant chemotherapy remains unproven. Emerging understanding of the underlying biology of stage II colon cancer has identified molecular markers that may change this paradigm and improve our risk assessment and treatment choices for stage II disease. Assessment of microsatellite stability (MSI), which serves as a marker for DNA mismatch repair (MMR) system function, has emerged as a useful tool for risk stratification of patients with stage II colon cancer. Patients with high frequency of MSI have been shown to have increased OS and limited benefit from 5-fluorouracil (5-FU)-based chemotherapy. Additional research is necessary to clearly define the most appropriate way to use this marker and others in routine clinical practice.


Assuntos
Carcinoma/patologia , Carcinoma/terapia , Neoplasias do Colo/patologia , Neoplasias do Colo/terapia , Oncologia/métodos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma/genética , Cromossomos Humanos Par 18 , Neoplasias do Colo/genética , Perfilação da Expressão Gênica , Marcadores Genéticos/genética , Marcadores Genéticos/fisiologia , Humanos , Perda de Heterozigosidade/fisiologia , Oncologia/normas , Instabilidade de Microssatélites , Estadiamento de Neoplasias
17.
Endocr Relat Cancer ; 18(3): 347-56, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21450940

RESUMO

Mutations of the aryl hydrocarbon receptor interacting protein (AIP) gene are associated with pituitary adenomas that usually occur as familial isolated pituitary adenomas (FIPA). Detailed pathological and tumor genetic data on AIP mutation-related pituitary adenomas are not sufficient. Non-identical twin females presented as adolescents to the emergency department with severe progressive headache caused by large pituitary macroadenomas require emergency neurosurgery; one patient had incipient pituitary apoplexy. Post-surgically, the patients were found to have silent somatotrope adenomas on pathological examination. Furthermore, the light microscopic, immunohistochemical, and electron microscopic studies demonstrated tumors of virtually identical characteristics. The adenomas were accompanied by multiple areas of pituitary hyperplasia, which stained positively for GH, indicating somatotrope hyperplasia. Genetic analyses of the FIPA kindred revealed a novel E216X mutation of the AIP gene, which was present in both the affected patients and the unaffected father. Molecular analysis of surgical specimens revealed loss of heterozygosity (LOH) in the adenoma but showed that LOH was not present in the hyperplastic pituitary tissue from either patient. AIP immunostaining confirmed normal staining in the hyperplastic tissue and decreased staining in the adenoma in the tumors from both patients. These results demonstrate that patients with AIP germline mutation can present with silent somatotrope pituitary adenomas. The finding of somatotrope hyperplasia unaccompanied by AIP LOH suggests that LOH at the AIP locus might be a late event in a potential progression from hyperplastic to adenomatous tissue.


Assuntos
Adenoma/genética , Adenoma Hipofisário Secretor de Hormônio do Crescimento/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Mutação , Hipófise/patologia , Adenoma/complicações , Adenoma/diagnóstico , Adolescente , Sequência de Bases , Progressão da Doença , Doenças em Gêmeos/diagnóstico , Doenças em Gêmeos/genética , Feminino , Adenoma Hipofisário Secretor de Hormônio do Crescimento/diagnóstico , Adenoma Hipofisário Secretor de Hormônio do Crescimento/patologia , Humanos , Hiperplasia , Perda de Heterozigosidade/fisiologia , Masculino , Mutação/fisiologia , Linhagem
18.
J Neurooncol ; 101(2): 207-13, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20535528

RESUMO

Glioblastoma multiforme is the most common type of primary brain tumor in adults. WWOX is a tumor suppressor gene involved in carcinogenesis and cancer progression in many different neoplasms. Reduced WWOX expression is associated with more aggressive phenotype and poor patient outcome in several cancers. We investigated alternations of WWOX expression and its correlation with proliferation, apoptosis and signal trafficking in 67 glioblastoma multiforme specimens. Moreover, we examined the level of WWOX LOH and methylation status in WWOX promoter region. Our results suggest that loss of heterozygosity (relatively frequent in glioblastoma multiforme) along with promoter methylation may decrease the expression of this tumor suppressor gene. Our experiment revealed positive correlations between WWOX and Bcl2 and between WWOX and Ki67. We also confirmed that WWOX is positively correlated with ErbB4 signaling pathway in glioblastoma multiforme.


Assuntos
Apoptose/fisiologia , Neoplasias Encefálicas/genética , Proliferação de Células , Regulação Neoplásica da Expressão Gênica/genética , Glioblastoma/genética , Oxirredutases/genética , Proteínas Supressoras de Tumor/genética , Adulto , Idoso , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/fisiopatologia , Receptores ErbB/genética , Receptores ErbB/metabolismo , Feminino , Glioblastoma/metabolismo , Glioblastoma/fisiopatologia , Humanos , Antígeno Ki-67/metabolismo , Perda de Heterozigosidade/fisiologia , Masculino , Pessoa de Meia-Idade , Oxirredutases/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Receptor ErbB-4 , Transdução de Sinais/genética , Estatística como Assunto , Proteínas Supressoras de Tumor/metabolismo , Oxidorredutase com Domínios WW
19.
Clin Cancer Res ; 16(18): 4553-60, 2010 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-20823145

RESUMO

Hypoxia exists in every solid tumor and is associated with poor prognosis because of both local and systemic therapeutic resistance. Recent studies have focused on the interaction between tumor cell genetics and the dynamic state of oxygenation and metabolism. Hypoxia generates aggressive tumor cell phenotypes in part owing to ongoing genetic instability and a "mutator" phenotype. The latter may be due to suppression of DNA mismatch repair (MMR), nucleotide excision repair (NER), and double-strand break (DSB) repair. We propose a theoretical model in which hypoxia-mediated defects in DNA repair can lead to "contextual loss of heterozygosity" and drive oncogenesis. Additionally, hypoxia-mediated repair defects can be specifically targeted by DNA damaging agents and/or "contextual synthetic lethality" to kill repair-deficient cells and preserve the therapeutic ratio. These proposed concepts support the interrogation of solid tumors to document repair defects in both oxic and hypoxic tumor subregions as a conduit to novel clinical trials within the context of personalized medicine.


Assuntos
Carcinógenos/toxicidade , Reparo do DNA/genética , Perda de Heterozigosidade/fisiologia , Neoplasias/genética , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Apoptose/fisiologia , Carcinógenos/farmacologia , Hipóxia Celular/efeitos dos fármacos , Hipóxia Celular/genética , Hipóxia Celular/fisiologia , Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/fisiologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/fisiologia , Instabilidade Genômica/efeitos dos fármacos , Instabilidade Genômica/fisiologia , Humanos , Perda de Heterozigosidade/efeitos dos fármacos , Perda de Heterozigosidade/genética , Modelos Biológicos , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/radioterapia , Falha de Tratamento
20.
Nat Genet ; 42(9): 801-5, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20676099

RESUMO

Hereditary persistence of fetal hemoglobin (HPFH) is characterized by persistent high levels of fetal hemoglobin (HbF) in adults. Several contributory factors, both genetic and environmental, have been identified but others remain elusive. HPFH was found in 10 of 27 members from a Maltese family. We used a genome-wide SNP scan followed by linkage analysis to identify a candidate region on chromosome 19p13.12-13. Sequencing revealed a nonsense mutation in the KLF1 gene, p.K288X, which ablated the DNA-binding domain of this key erythroid transcriptional regulator. Only family members with HPFH were heterozygous carriers of this mutation. Expression profiling on primary erythroid progenitors showed that KLF1 target genes were downregulated in samples from individuals with HPFH. Functional assays suggested that, in addition to its established role in regulating adult globin expression, KLF1 is a key activator of the BCL11A gene, which encodes a suppressor of HbF expression. These observations provide a rationale for the effects of KLF1 haploinsufficiency on HbF levels.


Assuntos
Hemoglobina Fetal/genética , Hemoglobina Fetal/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Adulto , Células Cultivadas , Eritropoese/genética , Família , Feminino , Regulação da Expressão Gênica no Desenvolvimento/genética , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/metabolismo , Humanos , Perda de Heterozigosidade/fisiologia , Masculino , Linhagem , Fatores de Transcrição/genética , Transfecção
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