title: Mutant p53 drives metastasis and overcomes growth arrest/senescence in pancreatic cancer.
abstract: TP53 mutation occurs in 50-75% of human pancreatic ductal adenocarcinomas (PDAC) following an initiating activating mutation in the KRAS gene. These p53 mutations frequently result in expression of a stable protein, p53(R175H), rather than complete loss of protein expression. In this study we elucidate the functions of mutant p53 (Trp53(R172H)), compared to knockout p53 (Trp53(fl)), in a mouse model of PDAC. First we find that although Kras(G12D) is one of the major oncogenic drivers of PDAC, most Kras(G12D)-expressing pancreatic cells are selectively lost from the tissue, and those that remain form premalignant lesions. Loss, or mutation, of Trp53 allows retention of the Kras(G12D)-expressing cells and drives rapid progression of these premalignant lesions to PDAC. This progression is consistent with failed growth arrest and/or senescence of premalignant lesions, since a mutant of p53, p53(R172P), which can still induce p21 and cell cycle arrest, is resistant to PDAC formation. Second, we find that despite similar kinetics of primary tumor formation, mutant p53(R172H), as compared with genetic loss of p53, specifically promotes metastasis. Moreover, only mutant p53(R172H)-expressing tumor cells exhibit invasive activity in an in vitro assay. Importantly, in human PDAC, p53 accumulation significantly correlates with lymph node metastasis. In summary, by using 'knock-in' mutations of Trp53 we have identified two critical acquired functions of a stably expressed mutant form of p53 that drive PDAC; first, an escape from Kras(G12D)-induced senescence/growth arrest and second, the promotion of metastasis.
authors.affiliation: Beatson Institute for Cancer Research, Glasgow G61 1BD, United Kingdom.
authors.forename: Jennifer P
authors.initials: JP
authors.lastname: Morton
authors.forename: Paul
authors.initials: P
authors.lastname: Timpson
authors.forename: Saadia A
authors.initials: SA
authors.lastname: Karim
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Ridgway
authors.forename: Dimitris
authors.initials: D
authors.lastname: Athineos
authors.forename: Brendan
authors.initials: B
authors.lastname: Doyle
authors.forename: Nigel B
authors.initials: NB
authors.lastname: Jamieson
authors.forename: Karin A
authors.initials: KA
authors.lastname: Oien
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Lowy
authors.forename: Valerie G
authors.initials: VG
authors.lastname: Brunton
authors.forename: Margaret C
authors.initials: MC
authors.lastname: Frame
authors.forename: T R Jeffry
authors.initials: TR
authors.lastname: Evans
authors.forename: Owen J
authors.initials: OJ
authors.lastname: Sansom
mesh_terms: D000818:Animals; D021441:Carcinoma, Pancreatic Ductal / Q000235:genetics / Q000473:pathology; D002453:Cell Cycle / Q000502:physiology; D016922:Cellular Senescence / Q000235:genetics*; D017930:Genes, Reporter; D006801:Humans; D051379:Mice; D046228:Microarray Analysis; D009154:Mutation; D009362:Neoplasm Metastasis / Q000235:genetics* / Q000473:pathology; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism
chemical_list: D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53; C495971:Hras protein, mouse; D016283:Proto-Oncogene Proteins p21(ras)