p53 targets identified by protein expression profiling

Abstract

p53 triggers cell cycle arrest and apoptosis through transcriptional regulation of specific target genes. We have investigated the effect of p53 activation on the proteome using 2D gel electrophoresis analysis of mitomycin C-treated HCT116 colon carcinoma cells carrying wild-type p53. Approximately 5,800 protein spots were separated in overlapping narrow-pH-range gel strips, and 115 protein spots showed significant expression changes upon p53 activation. The identity of 55 protein spots was obtained by mass spectrometry. The majority of the identified proteins have no previous connection to p53. The proteins fall into different functional categories, such as mRNA processing, translation, redox regulation, and apoptosis, consistent with the idea that p53 regulates multiple cellular pathways. p53-dependent regulation of five of the up-regulated proteins, eIF5A, hnRNP C1/C2, hnRNP K, lamin A/C, and Nm23-H1, and two of the down-regulated proteins, Prx II and TrpRS, was examined in further detail. Analysis of mRNA expression levels demonstrated both transcription-dependent and transcription-independent regulation among the identified targets. Thus, this study reveals protein targets of p53 and highlights the role of transcription-independent effects for the p53-induced biological response.proteomics ͉ transcription factor ͉ cancer

Distinct p53 genomic binding patterns in normal and cancer-derived human cells

“…Activation of p53 by mitomycin C in HCT116 cells was reported to induce transcription of lamin A and C, but p53 binding at that locus was not examined. 40 At the promoter of DCP1B (Fig. 2B), we confirmed highconfidence peak ID 42 (Table S2).…”

Proteomic identification of p53-dependent protein phosphorylation

“…Phosphorylation of Annexin I (ANXA1) was detected only in the p53 þ / þ cells upon MMC treatment (Figure 2a) Figure 2b, ANXA1 was upregulated as well as phosphorylated in a p53-dependent manner, consistent with our previous results (Rahman-Roblick et al, 2007).…”

“…Clearly, identification of new p53 targets is important to achieve a better understanding of the p53 tumor suppressor pathway. We have recently identified a series of novel p53 targets by protein-expression profiling (Rahman-Roblick et al, 2007). It is conceivable that p53 regulates targets at the posttranslational level, for example by affecting posttranslational modifications such as phosphorylation via transcriptional activation of kinases or other mechanisms.…”

“…This could be the mechanism behind phosphorylation of DJ-1. We have previously observed that mitogen-activated protein kinase (MAPK) 8, also known as c-Jun N-terminal protein kinase 1 (JNK1), is upregulated by p53 (Rahman-Roblick et al, 2007). This kinase is activated by various cellular stresses and mediates immediate-early gene expression in response to such stimuli.…”

Differential antiproliferative mechanisms of novel derivative of benzimidazo[1,2-α]quinoline in colon cancer cells depending on their p53 status

“…Several reports dealing with identification of p53 targets in colon carcinoma cells by proteomic tools have given prominence to Annexin I in p53-mediated apoptosis (22,23); for example, proteomic analysis of mitomycin C -treated HCT 116 cells carrying wt-p53 revealed Annexin I in the group of up-regulated proteins containing p53-binding site (23). Our proteomic analysis revealed an elevated expression of this protein in treated HCT 116 cells as well.…”