RESUMO
p53 and Notch-1 play important roles in breast cancer biology. Notch-1 inhibits p53 activity in cervical and breast cancer cells. Conversely, p53 inhibits Notch activity in T-cells but stimulates it in human keratinocytes. Notch co-activator MAML1 binds p53 and functions as a p53 co-activator. We studied the regulation of Notch signaling by p53 in MCF-7 cells and normal human mammary epithelial cells (HMEC). Results show that overexpression of p53 or activation of endogenous p53 with Nutlin-3 inhibits Notch-dependent transcriptional activity and Notch target expression in a dose-dependent manner. This effect could be partially rescued by transfection of MAML1 but not p300. Standard and quantitative co-immunoprecipitation experiments readily detected a complex containing p53 and Notch-1 in MCF-7 cells. Formation of this complex was inhibited by dominant negative MAML1 (DN-MAML1) and stimulated by wild-type MAML1. Standard and quantitative far-Western experiments showed a complex including p53, Notch-1, and MAML1. Chromatin immunoprecipitation (ChIP) experiments showed that p53 can associate with Notch-dependent HEY1 promoter and this association is inhibited by DN-MAML1 and stimulated by wild-type MAML1. Our data support a model in which p53 associates with the Notch transcriptional complex (NTC) in a MAML1-dependent fashion, most likely through a p53-MAML1 interaction. In our cellular models, the effect of this association is to inhibit Notch-dependent transcription. Our data suggest that p53-null breast cancers may lack this Notch-modulatory mechanism, and that therapeutic strategies that activate wild-type p53 can indirectly cause inhibition of Notch transcriptional activity.
Assuntos
Neoplasias da Mama/metabolismo , Proteínas de Ligação a DNA/metabolismo , Receptor Notch1/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Sítios de Ligação , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação a DNA/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Células MCF-7 , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Complexos Multiproteicos/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Interferência de RNA , Receptor Notch1/genética , Proteínas Serrate-Jagged , Fatores de Transcrição/genética , Transcrição Gênica , Transfecção , Proteína Supressora de Tumor p53/genéticaRESUMO
OBJECTIVE: The purpose of this project was to develop and test whole-grain continuing education for school foodservice personnel. METHODS: A continuing education program was developed to address planning, purchasing, preparing, and serving whole-grain food in schools. Participants completed a pre-post questionnaire to assess changes in knowledge, attitudes and intention. RESULTS: Participants (n = 211) were mostly non-Hispanic white women. Pre-post test scores indicated improvements in whole-grain knowledge and intention to find whole-grain recipes for school menus (P < 0.05); however, attitudes about storage and cost issues became less positive. After 3-6 months, participants indicated more whole-grain food items were offered in schools. CONCLUSIONS AND IMPLICATIONS: Whole-grain education for school foodservice personnel may increase awareness and menu placement and increase opportunities for whole-grain consumption by children.