The chemopreventive agent ?-difluoromethylornithine blocks Ki-ras-dependent tumor formation and specific gene expression in Caco-2 cells
| Autor: | Natalia A. Ignatenko, Hui Zhang, David E. Stringer, Bethany A. Skovan, George S. Watts, Eugene W. Gerner |
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| Rok vydání: | 2004 |
| Předmět: |
Cancer Research
Eflornithine Antineoplastic Agents Cell Communication Mice SCID Biology Ornithine Decarboxylase Transfection Proto-Oncogene Mas Ornithine decarboxylase Mice Western blot Cell Movement Gene expression medicine Animals Humans Molecular Biology Oligonucleotide Array Sequence Analysis Oncogene medicine.diagnostic_test Gene Expression Profiling Cell migration Ornithine Decarboxylase Inhibitors Endothelin 1 Molecular biology Neoplasm Proteins Gene expression profiling Genes ras Gene Expression Regulation Colonic Neoplasms Laminin Caco-2 Cells |
| Zdroj: | Molecular Carcinogenesis. 39:221-233 |
| ISSN: | 1098-2744 0899-1987 |
| DOI: | 10.1002/mc.20008 |
| Popis: | Mutation of the Kirsten-ras (Ki-ras) proto-oncogene occurs frequently in colorectal cancers. α-Difluoromethylornithine (DFMO), an irreversible inhibitor of the polyamine biosynthetic enzyme, ornithine decarboxylase (ODC), inhibits Ki-ras transformation and colon tumorigenesis in carcinogen-treated animal models by mechanisms yet to be elucidated. Caco-2 cells transfected with an activated Ki-ras, but not parental cells, formed tumors in severe combined immunodeficient (SCID) mice. DFMO treatment (2% in drinking water) prevented tumor growth. Gene expression profiling was performed to identify Ki-ras–and DFMO-dependent patterns of gene expression. Microarray results were validated with real-time or semi-quantitative RT-PCR and/or Western blot analysis. Genes upregulated in Caco-2 cells expressing an activated Ki-ras encoded cytoskeletal-, transport-, protease-, and gap junction–associated proteins. These genes are important for normal development and maintenance of colonic epithelial tissue. Caco-2 cells transfected with an activated Ki-ras displayed increased expression of the integrin alpha 1 (INGA1) and enhanced cell migration on laminin. These parameters were unaffected by DFMO, but Ki-ras–dependent migration was inhibited by INGA1 antibodies. Other Ki-ras–dependent, but DFMO-independent, genes included transglutaminase (TGase) and kallikrein 6 (KLK6). Ki-ras–transfected cells also expressed increased levels of connexin43 (Cx43) (RNA and protein), tight junction protein, and endothelin 1. DFMO reversed these increases. The results indicated that the Ki-ras oncogene caused changes in experimental cell migration and cell-cell communication genes and that some of these changes could be reversed by DFMO. © 2004 Wiley-Liss, Inc. |
| Databáze: | OpenAIRE |
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