title: Targeted expression of c-Src in epidermal basal cells leads to enhanced skin tumor promotion, malignant progression, and metastasis.
abstract: In this study, we generated transgenic mice that overexpressed either a constitutively active human c-src mutant (src(530)) or a wild-type human c-src (src(wt)) in epidermal basal cells driven by human keratin 14 (HK14) or bovine keratin 5 (BK5) promoters, respectively. HK14.src(530) transgenic mice developed severe epidermal hyperplasia and hyperkeratosis, and did not survive beyond 3 weeks of age. Four transgenic founders were obtained after injection of a BK5.src(wt) construct with variable phenotypes, and three lines (lines A-C) were established. BK5.src(wt) founder D exhibited a severe skin phenotype similar to HK14.src(530) transgenic mice and died 5 days after birth. Line C transgenic mice also exhibited significant epidermal hyperplasia and hyperkeratosis, and developed spontaneous squamous cell carcinomas (SCCs) of the skin beginning at approximately 3 months of age (70% incidence at 1 year). Mice from lines A and B did not show a marked phenotype; however, elevated human src(wt) protein in the epidermis of line B mice was clearly evident. Additional analyses of line B transgenic mice showed an enhanced responsiveness to 12-O-tetradecanoylphorbol-13-acetate-induced epidermal hyperplasia and cell proliferation. Analysis of the susceptibility of line B mice to two-stage skin carcinogenesis revealed that papillomas and SCCs arose earlier and in greater numbers compared with nontransgenic littermates. In addition, malignant conversion occurred more rapidly, and the SCCs that developed in line B transgenic mice had a greater propensity to metastasize to peripheral lymph nodes and other organs. These observations support the hypothesis that c-src plays an important role in skin tumor promotion. In addition, the data show that elevated c-src activity enhances malignant progression and metastasis in this model system.
authors.affiliation: Department of Carcinogenesis, University of Texas M. D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957, USA.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Jianghong
authors.initials: J
authors.lastname: Jiang
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kiguchi
authors.forename: Lynnsie
authors.initials: L
authors.lastname: Ruffino
authors.forename: Steve
authors.initials: S
authors.lastname: Carbajal
authors.forename: Linda
authors.initials: L
authors.lastname: Beltrán
authors.forename: David K
authors.initials: DK
authors.lastname: Bol
authors.forename: Michael P
authors.initials: MP
authors.lastname: Rosenberg
authors.forename: John
authors.initials: J
authors.lastname: DiGiovanni
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000595:Amino Acid Sequence; D000818:Animals; D000081247:CSK Tyrosine-Protein Kinase; D002294:Carcinoma, Squamous Cell / Q000209:etiology* / Q000473:pathology; D005260:Female; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009362:Neoplasm Metastasis; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000502:physiology*; D012867:Skin / Q000473:pathology; D012878:Skin Neoplasms / Q000209:etiology* / Q000473:pathology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019061:src-Family Kinases
chemical_list: D015127:9,10-Dimethyl-1,2-benzanthracene; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; D013755:Tetradecanoylphorbol Acetate