Functional study of the TP53 p.R337H mutation in cell lines grown under alkaline conditions

Abstract

TP53 is considered the most important tumor suppressor gene and acts as a potent transcription factor, playing a key role in maintaining genomic stability. The p53 protein consists of 393 amino acids and contains three structural domains, an N-terminal activation domain, a central DNA binding domain and a C-terminal oligomerization domain. A mutation in the p53 C-terminal domain is associated with a significantly higher incidence of pediatric adrenocortical tumors (ACT) in southern and southeastern Brazil. This mutation is an inherited germline arginine-to-histidine substitution at codon 337 (R337H) that leads to protein destabilization in alkaline pH (8.0), suggesting that this pH sensitivity could be the molecular basis for the ACT. However, no in vitro functional assays in alkaline pH has been reported in the literature to date. In a recent paper published by our group, it was reported that overexpression of AURKA was associated with the presence of the TP53 p.R337H mutation in ACT pediatric patients. Aurora-A is a member of a family of three homologous serine/threonine kinases that also comprises the Aurora-B and Aurora-C. These genes regulate the cell cycle and act mainly in mitosis. Aurora-A and Aurora-B expression is upregulated in several types of malignancies, including pediatric ACT, making these genes new promising therapeutic targets for cancer treatment. P53-deficient cells display an elevated expression of both Aurora-A and -B. These proteins interact with p53 through the C-terminal region regulating its stability and function. Different mutations in the p53 C-terminal domain may interfere with the p53 binding to Aurora-A and B. Based on these information, the purpose of this work is to study the TP53 p.R337H activity in cell lines grown under alkaline conditions and investigate the role of this mutation in the p53 interaction with Aurora-A and Aurora-B. The elucidation of the mechanisms underlying this mutation are essential for the development of more effective and/or individualized therapies for patients carrying the TP53 p.R337H mutation.