The oncogenicity of tumor-derived mutant p53 is enhanced by the recruitment of PLK3

Catherine A Vaughan,Steven R Grossman,Brad Windle,Raghavendra Pillappa,W Andrew Yeudall,Kazushi Inoue,Elizabeth A Fry,Mark A Subler,Sumitra Deb,Jolene J Windle,Shilpa Singh,Swati Palit Deb

doi:10.1038/s41467-021-20928-8

Abstract

p53 mutations with single amino acid changes in cancer often lead to dominant oncogenic changes. Here, we have developed a mouse model of gain-of-function (GOF) p53-driven lung cancer utilizing conditionally active LSL p53-R172H and LSL K-Ras-G12D knock-in alleles that can be activated by Cre in lung club cells. Mutation of the p53 transactivation domain (TAD) (p53-L25Q/W26S/R172H) eliminating significant transactivation activity resulted in loss of tumorigenicity, demonstrating that transactivation mediated by or dependent on TAD is required for oncogenicity by GOF p53. GOF p53 TAD mutations significantly reduce phosphorylation of nearby p53 serine 20 (S20), which is a target for PLK3 phosphorylation. Knocking out PLK3 attenuated S20 phosphorylation along with transactivation and oncogenicity by GOF p53, indicating that GOF p53 exploits PLK3 to trigger its transactivation capability and exert oncogenic functions. Our data show a mechanistic involvement of PLK3 in mutant p53 pathway of oncogenesis.

Highlights

P53 mutations with single amino acid changes in cancer often lead to dominant oncogenic changes
We have developed a lung tumor mouse model by expressing GOF p53-R172H and K-Ras (G12D) knock-ins in Club cells, in which tumor formation can be prevented by doxycycline (Dox)-inducible GOF p53 depletion
The resultant mice [LSL-R172H, LSL-K-Ras (G12D)] were crossed with mice expressing Cre recombinase from the Club cell secretory protein (CCSP) promoter, which is active in Club cells (CCSP-Cre)[31] to produce the final mouse model line [LSL-R172H, LSL-K-Ras (G12D), CCSP-Cre]

Summary

Introduction

P53 mutations with single amino acid changes in cancer often lead to dominant oncogenic changes. One mechanism of GOF by mutant p53 has been thought to be mutant p53-mediated transactivation of a series of proliferationand oncogenesis-related genes[19,20] after activation following phosphorylation It is, in general, speculated that mutant p53 upregulates gene expression by its nucleation on the target promoter via its interaction with a transcription factor (TF)[17,19,21]. While interaction with individual TFs in cultured cells has often been implicated in transcriptional activation[4,17,19,22], the communication scheme of GOF p53 with the TFs on target gene promoters needed for transactivation is elusive so far, and until now there is no evidence demonstrating that tumorigenicity induced by GOF p53 is mediated by its transactivation function in vivo. Mutations in WT p53 TAD at amino acids 22 and 23 prevent transactivation of many genes, and inhibit the interaction between WT p53 and Med1724,25

Methods

Results

Conclusion