Abstract 1719: Copper levels and the p53 protein: A delicate balance

Abstract

Abstract The tumor suppressor p53 is mutated in 50% of all cancers and in about 90% of small lung cancers. Mutations lead to loss of p53 expression or the expression of mutant p53 proteins. These mutants often lose WT function, but they have also been shown to acquire invasive and metastatic functions. p53 requires a zinc molecule in its core domain to fold properly and to function as a transcription factor and tumor suppressor. Loss of this zinc through competition with copper causes p53 to unfold and to lose its transcription function. Copper is an essential heavy metal required for a large variety of biological processes as it is required for the function of many enzymes. In cancer patients, increased serum levels of copper have been found and people with a predisposition for copper accumulation in the liver (Wilson’s disease, mutations in ATP7B) are prone to develop liver cancers. Our preliminary results have indicated that an unfolded WT p53 molecule does not only lose its transcription function, but also gains mutant p53-like functions in promoting invasion. Copper-induced unfolded p53 interacted with the mutant p53 specific interacting proteins Dicer, Ago, p63 and p73 and impaired p63 function. These results raise the question as to why a WT molecule would lose its function and whether it perhaps could act as a redox sensor. Experiments are ongoing to explore p53 mediated transcription in response to copper exposure. In addition, we are setting up mouse models to investigate p53 folding in vivo in response to mild increases in copper serum levels and we are developing methods to better determine p53 folding in patients and in mice. These results will help us assess p53 status in relation to serum metal levels in vivo and determine whether p53 is important in the development of cancers and metastasis. Citation Format: Patricia Muller, Yannick von Grabowiecki, Callum Hall. Copper levels and the p53 protein: A delicate balance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1719.