title: Rapid development of salivary gland carcinomas upon conditional expression of K-ras driven by the cytokeratin 5 promoter.
abstract: We have used a recently described model in which a ras oncogene is expressed in cytokeratin 5 (K5)-expressing cells on doxycycline administration to explore the effects of this oncogene in salivary glands of adult mice. Inducible expression of a mutated K-ras gene under the control of the K5 promoter led to the development of hyperplastic and dysplastic epithelial lesions and carcinomas, with an incidence of 100% and a minimum latency of a week. All major salivary glands were affected, as well as a set of previously undescribed buccal accessory salivary glands located on the apex of the masseter muscle, close to the oral angle. The tumors appear to arise from the cytokeratin 5-positive basal cell compartment. Myoepithelial cells participated in the hyperplasias but not in carcinomas, because the tumors are negative for smooth muscle actin. Carcinomas did not accumulate immunoreactive p53 but are positive for p63, as assayed by immunohistochemistry using an antibody against the N terminus of DeltaN p63, a splice variant of p63 that can inhibit p53 transcriptional activity. In this study, we provide evidence that the ras oncogene, targeted to a specifically sensitive cell compartment within the salivary glands, can trigger a series of event that are sufficient for full carcinogenesis.
authors.affiliation: Oral and Pharyngeal Cancer Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892-4340, USA.
authors.forename: Ana R
authors.initials: AR
authors.lastname: Raimondi
authors.forename: Lynn
authors.initials: L
authors.lastname: Vitale-Cross
authors.forename: Panomwat
authors.initials: P
authors.lastname: Amornphimoltham
authors.forename: J Silvio
authors.initials: JS
authors.lastname: Gutkind
authors.forename: Alfredo
authors.initials: A
authors.lastname: Molinolo
mesh_terms: D000818:Animals; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000473:pathology*; D049109:Cell Proliferation; D002610:Cheek / Q000473:pathology; D005260:Female; D018226:Fibroadenoma / Q000473:pathology*; D015972:Gene Expression Regulation, Neoplastic; D011905:Genes, ras; D007633:Keratins / Q000235:genetics*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009061:Mouth Mucosa / Q000473:pathology; D011401:Promoter Regions, Genetic; D012468:Salivary Gland Neoplasms / Q000235:genetics* / Q000473:pathology; D012469:Salivary Glands / Q000378:metabolism*; D013363:Submandibular Gland / Q000473:pathology
chemical_list: D007633:Keratins