Functional inactivation of p53 by antisense RNA induces invasive ability of lung carcinoma cells and downregulates cytokeratin synthesis.
Previously we had identified a p53 DNA-binding motif in the 5' region of the CK8 gene This finding led us to study the role of p53 protein in the regulation of CK8 gene expression and its role in tumorigenesis. Human lung cancer cell lines stably transfected with antisense p53 cDNA that expressed little p53 protein were analyzed. CK8 mRNA and the protein expression in these p53 antisense clones were very low as revealed by northern and western blot analysis. Immunofluorescence studies indicated that the cytokeratin networks around the nuclei of these cells collapsed; although some staining was observed around the nuclei. Antisense clones were highly invasive on in vitro matrigel assay. Scanning electron microscopy of the surface topography of these antisense clones revealed a large number of microvilli on their surfaces, a phenotype characteristic of tumor cell invasion. These findings suggest that functional inactivation p53 protein could be an important step in tumor progression.
Mukhopadhyay
T
T
Department of Thoracic and Cardiovascular Surgery, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
Roth
J A
JA
D015152:Blotting, Northern; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000473:pathology* / Q000648:ultrastructure; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic; D016158:Genes, p53; D006801:Humans; D007633:Keratins / Q000032:analysis / Q000096:biosynthesis*; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D009361:Neoplasm Invasiveness; D016372:RNA, Antisense; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000096:biosynthesis*
D004268:DNA-Binding Proteins; D016372:RNA, Antisense; D016159:Tumor Suppressor Protein p53; D007633:Keratins