Keith Wilson
Faculty Member
Last active: 11/2/2019

α-Difluoromethylornithine reduces gastric carcinogenesis by causing mutations in .

Sierra JC, Suarez G, Piazuelo MB, Luis PB, Baker DR, Romero-Gallo J, Barry DP, Schneider C, Morgan DR, Peek RM, Gobert AP, Wilson KT
Proc Natl Acad Sci U S A. 2019 116 (11): 5077-5085

PMID: 30804204 · PMCID: PMC6421409 · DOI:10.1073/pnas.1814497116

Infection by is the primary cause of gastric adenocarcinoma. The most potent virulence factor is cytotoxin-associated gene A (CagA), which is translocated by a type 4 secretion system (T4SS) into gastric epithelial cells and activates oncogenic signaling pathways. The gene encodes for a key component of the T4SS and can undergo gene rearrangements. We have shown that the cancer chemopreventive agent α-difluoromethylornithine (DFMO), known to inhibit the enzyme ornithine decarboxylase, reduces -mediated gastric cancer incidence in Mongolian gerbils. In the present study, we questioned whether DFMO might directly affect pathogenicity. We show that output strains isolated from gerbils treated with DFMO exhibit reduced ability to translocate CagA in gastric epithelial cells. Further, we frequently detected genomic modifications in the middle repeat region of the gene of output strains from DFMO-treated animals, which were associated with alterations in the CagY protein. Gerbils did not develop carcinoma when infected with a DFMO output strain containing rearranged or the parental strain in which the wild-type was replaced by with DFMO-induced rearrangements. Lastly, we demonstrate that in vitro treatment of by DFMO induces oxidative DNA damage, expression of the DNA repair enzyme MutS2, and mutations in , demonstrating that DFMO directly affects genomic stability. Deletion of abrogated the ability of DFMO to induce rearrangements directly. In conclusion, DFMO-induced oxidative stress in leads to genomic alterations and attenuates virulence.

MeSH Terms (15)

Animals Bacterial Proteins Carcinogenesis DNA Damage Eflornithine Gene Deletion Gene Rearrangement Gerbillinae Helicobacter pylori Male Mutation Oxidative Stress RNA, Messenger Stomach Neoplasms Virulence

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