Comparative gene expression profiling in response to p53 in a human lung cancer cell line

Abstract

The p53 tumor suppressor gene functions through the p53-mediated transcriptional activation and regulation of critical downstream target genes. The mechanism behind such regulation, however, remains unclear. In this study, we compared the expression of 30 genes that are involved in cell cycle checkpoint control and/or apoptosis in a human lung cancer cell line, which contains endogenous wild-type p53, in response to ectopic p53 expression. Of the 30 genes studied, 22 genes have shown an increase in expression. The increase in gene expression of 2 genes - Gadd45 and PIG2 - was more than 10-fold. These results suggest that the genes with the highest expression level in a p53-dependent pathway may play a dominant role in determining the pathway that the cell follows: cell cycle arrest or apoptosis. Our screen illustrates the development of a simple and inexpensive p53-specific cDNA array to begin to analyze downstream events in the p53 pathway under physiological, pathological, and stress-induced states.