title: Molecular analysis of a multistep lung cancer model induced by chronic inflammation reveals epigenetic regulation of p16 and activation of the DNA damage response pathway.
abstract: The molecular hallmarks of inflammation-mediated lung carcinogenesis have not been fully clarified, mainly due to the scarcity of appropriate animal models. We have used a silica-induced multistep lung carcinogenesis model driven by chronic inflammation to study the evolution of molecular markers and genetic alterations. We analyzed markers of DNA damage response (DDR), proliferative stress, and telomeric stress: gamma-H2AX, p16, p53, and TERT. Lung cancer-related epigenetic and genetic alterations, including promoter hypermethylation status of p16(CDKN2A), APC, CDH13, Rassf1, and Nore1A, as well as mutations of Tp53, epidermal growth factor receptor, K-ras, N-ras, and c-H-ras, have been also studied. Our results showed DDR pathway activation in preneoplastic lesions, in association with inducible nitric oxide synthase and p53 induction. p16 was also induced in early tumorigenic progression and was inactivated in bronchiolar dysplasias and tumors. Remarkably, lack of mutations of Ras and epidermal growth factor receptor, and a very low frequency of Tp53 mutations suggest that they are not required for tumorigenesis in this model. In contrast, epigenetic alterations in p16(CDKN2A), CDH13, and APC, but not in Rassf1 and Nore1A, were clearly observed. These data suggest the existence of a specific molecular signature of inflammation-driven lung carcinogenesis that shares some, but not all, of the molecular landmarks of chemically induced lung cancer.
authors.affiliation: Division of Oncology, Center for Applied Medical Research (CIMA), Pamplona, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Blanco
authors.forename: Silvestre
authors.initials: S
authors.lastname: Vicent
authors.forename: Mario F
authors.initials: MF
authors.lastname: Fraga
authors.forename: Ignacio
authors.initials: I
authors.lastname: Fernandez-Garcia
authors.forename: Javier
authors.initials: J
authors.lastname: Freire
authors.forename: Amaia
authors.initials: A
authors.lastname: Lujambio
authors.forename: Manel
authors.initials: M
authors.lastname: Esteller
authors.forename: Carlos
authors.initials: C
authors.lastname: Ortiz-de-Solorzano
authors.forename: Ruben
authors.initials: R
authors.lastname: Pio
authors.forename: Fernando
authors.initials: F
authors.lastname: Lecanda
authors.forename: Luis M
authors.initials: LM
authors.lastname: Montuenga
mesh_terms: D000818:Animals; D001483:Base Sequence; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002908:Chronic Disease; D004249:DNA Damage / Q000235:genetics*; D019175:DNA Methylation; D004252:DNA Mutational Analysis; D044127:Epigenesis, Genetic; D005260:Female; D017491:Genes, APC; D018773:Genes, erbB-1 / Q000235:genetics; D019942:Genes, p16; D016158:Genes, p53 / Q000235:genetics; D011905:Genes, ras / Q000235:genetics; D006657:Histones / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D007249:Inflammation / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D008175:Lung Neoplasms / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D009154:Mutation; D016133:Polymerase Chain Reaction; D011230:Precancerous Conditions / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D011401:Promoter Regions, Genetic; D051381:Rats; D011916:Rats, Inbred F344; D012822:Silicon Dioxide / Q000633:toxicity; D019098:Telomerase / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D015820:Cadherins; C099972:H-cadherin; D006657:Histones; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D012822:Silicon Dioxide; D019098:Telomerase