RESUMEN

The circadian clock exists in virtually every cell and regulates key biological processes in cells and tissues. Even in cancer cells, DNA synthesis, cell division and tumor growth are gated by the circadian clock. This study examined the gene expression profiles of transplanted mouse breast tumor cells under normal light-dark (LD) as well as constant dark (DD) conditions. It was found that the overall percentage of rhythmic transcripts in breast tumor tissue was lower than that in normal tissue. Few transcripts had unaltered rhythmic expression patterns under both LD and DD conditions. Most rhythmic transcripts in DD displayed 12h or shorter periods. These results suggest that in addition to the circadian clock control of gene transcription, altering light, feeding, physical activity and other factors characteristically affect the expression of many genes.

Asunto(s)

Biomarcadores de Tumor/genética , Proliferación Celular/efectos de la radiación , Ritmo Circadiano/fisiología , Oscuridad , Regulación Neoplásica de la Expresión Génica/fisiología , Luz , Neoplasias Mamarias Experimentales/genética , Animales , Biomarcadores de Tumor/metabolismo , Femenino , Perfilación de la Expresión Génica , Neoplasias Mamarias Experimentales/metabolismo , Neoplasias Mamarias Experimentales/patología , Ratones , Ratones Endogámicos C3H , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN Mensajero/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa