RESUMEN
The death-associated protein 3 (DAP3) is a highly conserved phosphoprotein involved in the regulation of autophagy. A previous clinical study by our group suggested an association between low DAP3 expression and clinicopathological parameters of human breast cancer. In the present study, we intended to determine the role of DAP3 in cancer cell behaviour in the context of human breast cancer. We developed knockdown sub-lines of MCF7 and MDA-MB-231, and performed growth, adhesion, invasion assays and electric cell-substrate impedance sensing (ECIS) studies of post-wound migration of the cells. In addition, we studied the mRNA expression of caspase 8 and 9, death ligand signal enhancer (DELE), IFN-ß promoter stimulator 1 (IPS1), cyclin D1 and p21 in the control and knockdown sub-lines. The knockdown sub-lines of MCF7 and MDA-MB-231 had significantly increased adhesion and decreased growth when compared to the controls. Furthermore, invasion and migration were significantly increased in the MDA-MB-231DAP3kd cells vs. the controls. The expression of caspase 9 and IPS1, known components of the apoptosis pathway, were significantly reduced in the MCF7DAP3kd cells (p=0.05 and p=0.003, respectively). We conclude that DAP3 silencing contributes to breast carcinogenesis by increasing cell adhesion, migration and invasion. It is possible that this may be due to the activity of focal adhesion kinase further downstream of the anoikis pathway. Further research in this direction would be beneficial in increasing our understanding of the mechanisms underlying human breast cancer.
Asunto(s)
Proteínas Reguladoras de la Apoptosis/genética , Neoplasias de la Mama/genética , Adhesión Celular/genética , Movimiento Celular/genética , Proliferación Celular/genética , Proteínas Ribosómicas/genética , Proteínas Adaptadoras Transductoras de Señales/genética , Apoptosis/genética , Neoplasias de la Mama/patología , Caspasa 8/genética , Caspasa 9/genética , Línea Celular Tumoral , Ciclina D1/genética , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Femenino , Proteína-Tirosina Quinasas de Adhesión Focal/genética , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Células MCF-7 , Proteínas Mitocondriales/genética , Invasividad Neoplásica/genética , Invasividad Neoplásica/patología , Proteínas de Unión al ARN , Transducción de Señal/genéticaRESUMEN
Death-associated protein 1 (DAP1) is a highly conserved phosphoprotein involved in the regulation of autophagy. A previous clinical study by our group suggested an association between low DAP1 expression and clinicopathological parameters of human breast cancer. In the present study, we aimed to determine the role of DAP1 in cancer cell behaviour in the context of human breast cancer. We developed knockdown sublines of MCF7 and MDA-MB231, and performed growth, adhesion and invasion assays and electric cell-substrate impedance sensing (ECIS) studies of the post-wound migration of cells. In addition, we studied the mRNA expression of caspase 8 and 9, DELE, IPS1, cyclin D1 and p21 in the control and knockdown sublines. Knockdown was associated with increased adhesion and migration, significantly so in the MDA-MB-231DAP1kd cell subline (p=0.029 and p=0.001, respectively). Growth in MCF7 cells showed a significant suppression on day 3 (p=0.029), followed by an increase in growth matching the controls on day 5. While no change in the apoptotic response to serum starvation could be attributed to DAP1 knockdown, the expression of known components of the apoptosis pathway (caspase 8) and cell cycle (p21) was significantly reduced in the MCF7DAP1kd cell subline (p≤0.05), while in MDA-MB-231DAP1kd the expression of a pro-apoptotic molecule, IPS1, was suppressed (p≤0.05). DAP1 may have an important role in cell adhesion, migration and growth in the context of breast cancer and has significant associations with the apoptosis pathway. Furthermore, we believe that delayed increase in growth observed in the MCF7DAP1kd cell subline may indicate activation of a strongly pro-oncogenic pathway downstream of DAP1.
