title: Murine squamous cell carcinoma cell lines produced by a complete carcinogenesis protocol with benzo[a]pyrene exhibit characteristic p53 mutations and the absence of H-ras and cyl 1/cyclin D1 abnormalities.
abstract: In this report, we describe the isolation and characterization of six murine squamous cell carcinoma cell lines (BPCC) derived from carcinomas produced by a complete carcinogenesis protocol with benzo[a]pyrene (B[a]P). All six cell lines were tumorigenic to varying degrees in nude mice, and several were spontaneously metastatic to the lungs. The in vivo invasive potential of each BPCC cell line was determined using de-epithelialized tracheal xenotransplants into which cells were inoculated. This assay revealed positive association of tumor grade with in vivo invasiveness, yet no clear relationship to the spontaneous metastatic potential of the cell lines, suggestive that invasive potential is only one determinant of the overall metastatic phenotype. At the molecular level, all six BPCC cell lines revealed the absence of mutations in the H-ras oncogene and no amplification or rearrangement in the cycl 1/cyclin D1 putative oncogene. Analysis of the p53 tumor suppressor gene revealed a direct correlation between positive nuclear immunohistochemical staining of the p53 protein in four BPCC cell lines and the presence of p53 mutations identified by direct sequence analysis. The localization of mutations to exons 7 and 8 of the p53 gene and the detection of G to T transversions in two of the four cell lines bearing p53 mutations are in agreement with previous analyses of a large series of primary B[a]P-induced murine skin tumors. In addition, frameshift mutations were identified in two cell lines. The correlation of the biological and molecular properties of these BPCC cell lines with the known characteristics of primary squamous cell carcinomas induced by B[a]P indicates that these cell lines could be useful tools in elucidating the mechanisms of tumorigenesis of this important chemical carcinogen.
authors.affiliation: Department of Pathology, Fox Chase Cancer Center, Philadelphia, PA 1911.
authors.forename: B A
authors.initials: BA
authors.lastname: Ruggeri
authors.forename: B
authors.initials: B
authors.lastname: Bauer
authors.forename: S Y
authors.initials: SY
authors.lastname: Zhang
authors.forename: A J
authors.initials: AJ
authors.lastname: Klein-Szanto
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D019938:Cyclin D1; D016213:Cyclins / Q000235:genetics*; D016158:Genes, p53; D011905:Genes, ras; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D015513:Oncogene Proteins / Q000235:genetics*; D051381:Rats; D012878:Skin Neoplasms / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology
chemical_list: D016213:Cyclins; D015513:Oncogene Proteins; D019938:Cyclin D1; D001564:Benzo(a)pyrene