RESUMO
Normal monomeric tau can be converted into pathogenic aggregates and acquire protease resistance in a prion-like manner. This acquisition of partial protease-resistance in tau aggregates has to date only been partially investigated in various studies exploring the prion-like properties of tau. In this study, we induced the aggregation of tau repeat domain (RD) in cultured cells using detergent insoluble fractions of Alzheimer's brain tissue as seeds. The seeded aggregation of tau RD in cultured cells formed a ~7 kDa protease-resistant fragment in contrast to the ~12 kDa tau fragment characteristic of the AD seeds, suggesting that the in vitro generated tau aggregates were conformationally distinct from parent seeds.
Assuntos
Doença de Alzheimer/metabolismo , Encéfalo/patologia , Agregados Proteicos , Proteínas tau/química , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteínas de Fluorescência Verde/metabolismo , Células HEK293 , Humanos , Pessoa de Meia-Idade , Peptídeo Hidrolases/metabolismo , Conformação Proteica , Proteínas Recombinantes/metabolismo , Sarcosina/análogos & derivados , Sarcosina/metabolismo , SolubilidadeRESUMO
We investigated the tumor suppressor activity and regulatory mechanism of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in gastric cancer; 15-PGDH expression was lost in 70.1% of malignant human gastric tissues, but was preserved in normal and metaplastic gastritis. KATO III and SNU-719 cells were transfected with pcDNA3.1-empty vector or an expression vector encoding wild-type 15-PGDH. In TUNEL assays apoptotic cell numbers were increased in KATO-PGDH-WT cells compared with control. We found that EGFR and ERK1/2 inhibitors clearly increased the expression of 15-PGDH in KATO III cells. Our findings demonstrate both downregulation and a tumor suppressor activity of 15-PGDH in gastric cancer.
Assuntos
Adenoma/enzimologia , Carcinoma/enzimologia , Gastrite/enzimologia , Hidroxiprostaglandina Desidrogenases/metabolismo , Lesões Pré-Cancerosas/enzimologia , Neoplasias Gástricas/enzimologia , Proteínas Supressoras de Tumor/metabolismo , Adenoma/genética , Adenoma/patologia , Apoptose , Carcinoma/genética , Carcinoma/patologia , Linhagem Celular Tumoral , Proliferação de Células , Dinoprostona/metabolismo , Regulação para Baixo , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/metabolismo , Gastrite/genética , Gastrite/patologia , Humanos , Hidroxiprostaglandina Desidrogenases/genética , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Metaplasia , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/patologia , Inibidores de Proteínas Quinases/farmacologia , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Fatores de Tempo , Transfecção , Proteínas Supressoras de Tumor/genéticaRESUMO
Although obesity is a risk factor for colorectal cancer, the underlying mechanism is not clear. Adiponectin is an adipokine that binds to 2 types of receptors, AdipoR1 and AdipoR2. The plasma concentrations of adiponectin are reduced in obese individuals and adiponectin has been reported to have anticarcinogenic properties. Furthermore, AdipoR1 and AdipoR2 have been reported to be expressed in several malignancies. However, little is known about the expression of AdipoR1 and AdipoR2 in colorectal cancer and its clinicopathological implications. In addition, the relationship between adiponectin and colorectal cancer has not yet been determined. Here, we sought to investigate adiponectin and adiponectin receptors in relation to colorectal cancer. AdipoR1 and AdipoR2 immunostaining was detected in 72 and 68% of human colorectal cancer tissue, respectively. AdipoR1 and AdipoR2 expression levels were inversely related to T stage. The lowest AdipoR1 and AdipoR2 expression were detected in poorly differentiated adenocarcinoma. RT-PCR also showed the expression of AdipoR1 and AdipoR2 in HCT116 and SW620. MTT assay and TUNEL assay demonstrated the tendency of growth inhibition and apoptosis induction in both cell lines after full-length adiponectin treatment although statistically insignificant. Microarray analysis revealed several gene responses to full-length adiponectin, including upregulation of ENDOGL1 and MT1G. In conclusion, AdipoR1 and AdipoR2 may be intimately related to the progression of colorectal cancer. Further studies may be warranted to assess adiponectin and its receptors as a novel target for inhibition of colorectal cancer growth.
Assuntos
Adenocarcinoma/metabolismo , Adiponectina/metabolismo , Biomarcadores Tumorais/metabolismo , Neoplasias Colorretais/metabolismo , Receptores de Adiponectina/metabolismo , Adenocarcinoma/genética , Adiponectina/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Apoptose , Biomarcadores Tumorais/genética , Western Blotting , Diferenciação Celular , Proliferação de Células , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Progressão da Doença , Feminino , Perfilação da Expressão Gênica , Humanos , Técnicas Imunoenzimáticas , Masculino , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , RNA Mensageiro/genética , Receptores de Adiponectina/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de RiscoRESUMO
A Helicobacter pylori mutant defective in a putative mfd gene was constructed and characterized. The mfd gene is required for DNA repair and is involved in DNA recombination processes. The mfd mutant strain displayed a greatly increased susceptibility to antibiotics, indicating that this gene plays a significant role in the antibiotic resistance of H. pylori strain J99.