Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros












Base de dados
Intervalo de ano de publicação
1.
Histopathology ; 65(4): 473-82, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24592973

RESUMO

AIMS: To perform a population-based review of monomorphic endometrial stromal tumours and their histological mimics presenting over a 20-year period, including an evaluation of fluorescence in-situ hybridization (FISH) for the JAZF1 and YWHAE breakaparts. METHODS AND RESULTS: Forty-nine tumours were examined, comprising 13 histological mimics and 36 endometrial stromal tumours [six stromal nodules (ESNs), 25 low-grade stromal sarcomas (ESSs), and five monomorphic undifferentiated sarcomas (mUESs)]. Nine ESSs showed variant histological patterns, including smooth muscle, sex cord-like/glandular, fibrous or rhabdoid differentiation. Three ESSs were initially misclassified as benign uterine lesions, and, conversely, three benign mimics were originally reported as ESSs. One mUES showed a prominent pseudopapillary pattern. Fluorescence in-situ hybridization demonstrated JAZF1 breakaparts in five of six ESNs and 16 of 25 ESSs; however, only three of nine ESS variants were positive. YWHAE breakaparts were present in four of five mUESs. Analysis of a subsequent metastasis in the YWHAE breakapart-negative mUES demonstrated a YWHAE deletion. None of the histological mimics was positive in FISH analysis. Diffuse cyclin D1 expression was restricted to mUESs in this series. CONCLUSIONS: Endometrial stromal neoplasms continue to present diagnostic difficulty. Fluorescence in-situ hybridization analysis is helpful in distinguishing stromal tumours from their histological mimics and in distinguishing ESS from mUES.


Assuntos
Neoplasias do Endométrio/diagnóstico , Tumores do Estroma Endometrial/diagnóstico , Hibridização in Situ Fluorescente , Proteínas 14-3-3/análise , Adulto , Idoso , Austrália , Proteínas Correpressoras , Ciclina D1/isolamento & purificação , Proteínas de Ligação a DNA , Diagnóstico Diferencial , Neoplasias do Endométrio/patologia , Tumores do Estroma Endometrial/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Proteínas de Neoplasias/análise , Translocação Genética/genética
2.
Exp Mol Med ; 35(5): 421-30, 2003 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-14646596

RESUMO

CDK2 and CDK4 known promoter of cell cycling catalyze phosphorylation of RB protein. Enzyme specificity between two CDKs that work at a different cell cycle phase is not clearly understood. In order to define kinase properties of CDK2 and CDK4 in complex with cycline A or cycline D1 in relation to their respective role in cell cycling regulation, we examined enzymatic properties of both CDK4/cycline D1 and CDK2/cycline A in vitro. Association constant, Km for ATP in CDK4/cyclin D1 was found as 418 microM, a value unusually high whereas CDK2/cyclin A was 23 microM, a value close to most of other regulatory protein kinases. Turnover value for both CDK4/cyclin D1 and CDK2/cyclin A were estimated as 3.4 and 3.9 min(-1) respectively. Kinetic efficiency estimation indicates far over one order magnitude less efficiency for CDK4/cyclin D1 than the value of CDK2/cycline A (9.3 pM(-1) min(-1) and 170 pM(-1) min(-1) respectively). In addition, inhibition of cellular CDK4 caused increase of cellular levels of ATP, even though inhibition of CDK2 did not change it noticeably. These data suggest cellular CDK4/cyclin D1 activity is tightly associated with cellular ATP concentration. Also, analysis of phosphorylated serine/threonine sites on RB catalyzed by CDK4/cyclin D1 and CDK2/cyclin A showed significant differences in their preference of phosphorylation sites in RB C-terminal domain. Since RB is known to regulate various cellular proteins by binding and this binding is controlled by its phosphorylation, these data shown here clearly indicate significant difference in their biochemical properties between CDK4/cyclin D1 and CDK2/cyclin A affecting regulation of cellular RB function.


Assuntos
Quinases relacionadas a CDC2 e CDC28/metabolismo , Ciclina A/metabolismo , Ciclina D1/metabolismo , Quinases Ciclina-Dependentes/metabolismo , Proteínas Proto-Oncogênicas , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Baculoviridae/genética , Quinases relacionadas a CDC2 e CDC28/genética , Quinases relacionadas a CDC2 e CDC28/isolamento & purificação , Ciclina A/genética , Ciclina A/isolamento & purificação , Ciclina D1/genética , Ciclina D1/isolamento & purificação , Quinase 2 Dependente de Ciclina , Quinase 4 Dependente de Ciclina , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Quinases Ciclina-Dependentes/antagonistas & inibidores , Quinases Ciclina-Dependentes/genética , Quinases Ciclina-Dependentes/isolamento & purificação , Humanos , Cinética , Dados de Sequência Molecular , Fosforilação , Conformação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo
3.
Oncogene ; 20(12): 1445-54, 2001 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-11313888

RESUMO

Transgenic mice expressing specific oncogenes usually develop tumors in a stochastic fashion suggesting that tumor progression is a multi-step process. To gain further understanding of the interactions between oncogenes and tumor suppressor genes during tumorigenesis, we have crossed a transgenic strain (TG.NK) carrying an activated c-neu oncogene driven by the MMTV enhancer/promoter with p53-deficient mice. c-neu transgenic mice have stochastic breast tumor formation and normal appearing salivary glands. However, c-neu mice heterozygous for a p53 deletion develop parotid gland tumors and loose their wild type p53 allele. c-neu mice with a homozygous p53 deletion have increased rates of parotid tumor onset suggesting that inactivation of p53 is required and sufficient for parotid gland transformation in the presence of activated c-neu. In contrast to the dramatic effect of p53 in parotid gland transformation, p53 loss has little effect on the rate or stochastic appearance of mammary tumors. In addition, p53 loss was accompanied by the down regulation of p21 in parotid gland tumors but not breast tumors. The parotid gland tumors were aneuploid and demonstrated increased levels of Cyclin D1 expression. These observations suggest that in c-neu transgenic mice, p53 alterations have differential tissue effects and may be influenced by the tissue specific expression of genes influencing p53 activity.


Assuntos
Genes erbB-2 , Genes p53 , Neoplasias das Glândulas Salivares/genética , Aneuploidia , Animais , Transformação Celular Neoplásica/genética , Ciclina D1/isolamento & purificação , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/isolamento & purificação , Feminino , Regulação Neoplásica da Expressão Gênica , Perda de Heterozigosidade , Masculino , Neoplasias Mamárias Animais/etiologia , Neoplasias Mamárias Animais/genética , Camundongos , Camundongos Transgênicos , Neoplasias Parotídeas/genética , Neoplasias das Glândulas Salivares/etiologia , Glândulas Salivares/metabolismo , Processos Estocásticos , Distribuição Tecidual , Proteína Supressora de Tumor p53/isolamento & purificação
4.
Oncogene ; 19(10): 1307-17, 2000 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-10713672

RESUMO

Using single and double transgenic mouse models, we investigated how c-Myc modulates the mammary epithelial cell cycle to induce cancer and how TGFalpha enhanced the process. In c-myc transgenic mice, c-myc expression was high in the hyperplastic mammary epithelium and in the majority of tumor areas. However, the tumors displayed focal areas of low expression of c-myc but high rates of proliferation. In contrast to E2F1 and cyclin A2, which were induced and co-localized with c-myc expression, induction of cyclins D1 and E occurred only in these tumor foci. Overexpression of cyclin D1 also occurred in the hyperplastic epithelium of tgfalpha-single and tgfalpha/c-myc-double transgenic mice. In tgfalpha/c-myc tumors, cells positive for cyclins D1 and E were randomly spread, without showing a reciprocal relationship to c-myc expression. In contrast to c-myc tumors, most tgfalpha/c-myc tumors showed undetectable levels of retinoblastoma protein (pRB), and the loss of pRB occurred in some cases at the mRNA level. These results suggest that E2F1 and cyclin A2 may be induced by c-Myc to mediate the onset of mammary cancer, whereas overexpression of cyclins D1 and E may occur later to facilitate tumor progression. TGFalpha may play its synergistic role, at least in part, by inducing cyclin D1 and facilitating the loss of pRB.


Assuntos
Proteínas de Transporte , Proteínas de Ciclo Celular , Transformação Celular Neoplásica/genética , Proteínas de Ligação a DNA , Neoplasias Mamárias Experimentais/genética , Proteínas Proto-Oncogênicas c-myc/genética , Fator de Crescimento Transformador alfa/genética , Animais , Apoptose , Ciclo Celular/genética , Ciclina A/isolamento & purificação , Ciclina D1/isolamento & purificação , Ciclina D3 , Ciclina E/isolamento & purificação , Quinases Ciclina-Dependentes/antagonistas & inibidores , Ciclinas/isolamento & purificação , Fatores de Transcrição E2F , Fator de Transcrição E2F1 , Células Epiteliais , Feminino , Hibridização In Situ , Marcação In Situ das Extremidades Cortadas , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Transgênicos , Modelos Biológicos , Proteína do Retinoblastoma/isolamento & purificação , Proteína 1 de Ligação ao Retinoblastoma , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Transcrição DP1 , Fatores de Transcrição/isolamento & purificação
5.
J Histochem Cytochem ; 46(3): 397-403, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9487122

RESUMO

We describe and discuss a method of protein extraction for Western blot analysis from formalin-fixed, paraffin-embedded tissue sections. From 5-mm2 50-micron-thick tissue sections, an abundance of proteins could be extracted by incubating the sections in lysis buffer containing 2% sodium dodecyl sulfate (SDS) at 100C for 20 min followed by incubation at 60C for 2 hr. Extracts yielded discernible protein bands ranging from 10 kD to 120 kD as identified by SDS-polyacrylamide gel electrophoresis (PAGE). Western blot analysis successfully detected membrane-bound protein such as E-cadherin, cytosolic protein such as beta-catenin, and nuclear proteins including proliferating cell nuclear antigen (PCNA), mutant-type p53, cyclin D1, cyclin E, and cyclin-dependent kinases (CDKs). With this technique, we could examine cyclin D1 and CDK2 expression in small adenomas compared with cancer tissues and normal mucosa. The simple method of protein extraction described here should make it possible to use large-scale archives of formalin-fixed, paraffin-embedded samples for Western blot analysis, and its application could lead to detailed analysis of protein expression. This new technique should yield valuable information for molecular biology.


Assuntos
Western Blotting/métodos , Quinases relacionadas a CDC2 e CDC28 , Formaldeído , Parafina , Proteínas/isolamento & purificação , Adenoma/química , Neoplasias Colorretais/química , Ciclina D1/química , Ciclina D1/isolamento & purificação , Quinase 2 Dependente de Ciclina , Quinases Ciclina-Dependentes/química , Quinases Ciclina-Dependentes/isolamento & purificação , Humanos , Proteínas Nucleares/química , Proteínas Nucleares/isolamento & purificação , Antígeno Nuclear de Célula em Proliferação/química , Antígeno Nuclear de Célula em Proliferação/isolamento & purificação , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/isolamento & purificação , Proteínas/química , Fixação de Tecidos
6.
Exp Cell Res ; 237(1): 127-34, 1997 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-9417875

RESUMO

The association of cyclin D1 with nuclear structures was investigated in normal human fibroblasts by using hypotonic detergent extraction procedures, immunofluorescence quantitation with flow cytometry, and Western blot analysis. About 20% of the total cellular levels of cyclin D1 was found to be tightly bound to nuclear structures, being the complex formation resistant to DNase I treatment and to high salt extraction. Maximal levels of the insoluble form of the protein were found in the middle to late G1 phase of the cell cycle. Cell fractionation and immunoprecipitation techniques after in vivo 32P-labeling showed that both soluble and nuclear-bound forms of cyclin D1 were phosphorylated. Both fractions were reactive to an anti-phosphotyrosine antibody, while only the latter was detectable with an anti-phosphoserine antibody. Treatment with the protein kinase inhibitor staurosporine, which induces a cell cycle arrest in early G1 phase, strongly reduced cyclin D1 phosphorylation. Concomitantly, the ratio of nuclear-bound/total cyclin D1 levels was reduced by about 60%, compared with the control value. The protein kinase A specific inhibitor isoquinoline-sulfonamide (H-89) induced a similar reduction in the ratio, with no significant modification in the total amount of protein. In contrast, both calphostin C and bisindolylmaleimide, specific inhibitors of protein kinase C, consistently increased by 30-50% the ratio of nuclear-bound/total amount of the cyclin protein. These results suggest that, during the G1 phase, formation of an insoluble complex of cyclin D1 occurs at nuclear matrix structures and that this association is mediated by a protein kinase A-dependent pathway.


Assuntos
Núcleo Celular/fisiologia , Ciclina D1/metabolismo , Inibidores Enzimáticos/farmacologia , Isoquinolinas/farmacologia , Inibidores de Proteínas Quinases , Estaurosporina/farmacologia , Sulfonamidas , Divisão Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/ultraestrutura , Células Cultivadas , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Ciclina D1/efeitos dos fármacos , Ciclina D1/isolamento & purificação , Fibroblastos , Humanos , Indóis/farmacologia , Pulmão , Maleimidas/farmacologia , Naftalenos/farmacologia , Fosforilação , Ligação Proteica , Proteína Quinase C/antagonistas & inibidores
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...