RESUMEN
A central role for polo-like kinases (PLK) in regulating several stages of mitotic progression has been born out in several species. Overexpression of PLK1 is observed in the majority of hitherto analysed human tumors. PLK1 overexpression is a negative prognostic factor in patients suffering from non-small cell lung cancer, head and neck tumors, esophageal carcinomas and melanomas. In order to define the role of PLK1 for mitotic progression of human cells and for neoplastic cell growth, phosphorothioate antisense oligonucleotides (ASOs) were tested to selectively downregulate PLK1 expression in MDA-MB-435 (breast cancer), HeLa S3 (cervical carcinoma) and A549 (non-small cell lung cancer) cells. ASOs were identified which suppress PLK1 mRNA and protein in a dose-dependent and sequence-specific manner. This approach also led to reduced PLK1 serine/threonine kinase activity. Downregulation of cellular PLK1 levels in cancer cells altered cell cycle progression moderately with an elevated percentage (20-30%) of cells in G(2)/M. Furthermore, cells with reduced PLK1 protein gained a rounded phenotype with multiple centrosomes. Moreover, ASO treatment resulted in potent antiproliferative effects in cell culture. Considerable antitumor activity was observed in vivo against A549 cells. This study suggests that antisense inhibitors targeted against PLK1 at well tolerated doses may be considered as a cancer therapeutic agent.
Asunto(s)
Antineoplásicos/farmacología , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Proteínas de Neoplasias/fisiología , Oligonucleótidos Antisentido/farmacología , Proteínas Quinasas/fisiología , Tionucleótidos/farmacología , Adenocarcinoma/enzimología , Adenocarcinoma/patología , Neoplasias de la Mama/enzimología , Neoplasias de la Mama/patología , Carcinoma de Pulmón de Células no Pequeñas/enzimología , Carcinoma de Pulmón de Células no Pequeñas/patología , Ciclo Celular/efectos de los fármacos , Proteínas de Ciclo Celular , División Celular , Relación Dosis-Respuesta a Droga , Inducción Enzimática , Células HeLa/efectos de los fármacos , Células HeLa/enzimología , Humanos , Neoplasias Pulmonares/enzimología , Neoplasias Pulmonares/patología , Mitosis/efectos de los fármacos , Proteínas de Neoplasias/biosíntesis , Proteínas de Neoplasias/genética , Oligonucleótidos Antisentido/administración & dosificación , Proteínas Quinasas/biosíntesis , Proteínas Quinasas/genética , Proteínas Serina-Treonina Quinasas , Proteínas Proto-Oncogénicas , ARN Mensajero/biosíntesis , ARN Neoplásico/biosíntesis , Tionucleótidos/administración & dosificación , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/enzimología , Quinasa Tipo Polo 1RESUMEN
The proliferative stimulus of the epidermal growth factor (EGF) in human epithelial cells is mediated by its binding to the external domain of the EGF receptor (EGF-R). The purpose of this study was to investigate whether growth arrest of tumors treated with anti-EGF-R MAb (EMD 55900) was dependent on EGF-R expression and distinct histopathologic criteria of those neoplasms. Nine different adenocarcinomas, squamous cell carcinomas and two neoplastic epithelial cell lines (A431 and Detroit 562), which were characterized by high EGF-R expression, were xenotransplanted onto NMRI-nu/nu mice and treated with an anti-EGF-R antibody (EMD 55900). Results revealed that EGF-R expression and distinct histopathologic growth patterns play an important role for the therapeutic effect of the EGF-R antibody treatment. Tumors with high epithelial cellularity and little connective tissue responded to EMD 55900 treatment to a greater degree of growth reduction than tumors with lower cellularity. These results will be helpful for evaluation of patients who would benefit from tumor therapy with anti-EGF-R antibody.