12-O-tetradecanoylphorbol-13-acetate induces clonal expansion of potentially malignant keratinocytes in a tissue model of early neoplastic progression

• Verfasst von: Karen, Jeffrey [VerfasserIn]
• Verfasst von: Fusenig, Norbert [VerfasserIn]
• Titel: 12-O-tetradecanoylphorbol-13-acetate induces clonal expansion of potentially malignant keratinocytes in a tissue model of early neoplastic progression
• Verf.angabe: Jeffrey Karen, Youai Wang, Ashkan Javaherian, Michael Vaccariello, Norbert E. Fusenig, and Jonathan A. Garlick
• E-Jahr: 1999
• Jahr: January 1, 1999
• Umfang: 8 S.
• Fussnoten: Gesehen am 11.02.2021
• Titel Quelle: Enthalten in: Cancer research
• Ort Quelle: Philadelphia, Pa. : AACR, 1916
• Jahr Quelle: 1999
• Band/Heft Quelle: 59(1999), 2, Seite 474-481
• ISSN Quelle: 1538-7445
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1748118935

Abstract

Tumor promoters stimulate the selective expansion of initiated mouse keratinocytes in the two-stage model of skin carcinogenesis. However, it is not clear whether these promoters directly modulate the growth of initiated cells or rather permit clonal expansion of initiated cells by modifying the environment of adjacent normal cells. The goal of this study was to further understand the mechanism of action of tumor promotion during early neoplastic progression of human stratified epithelium. To accomplish this, we have established an organotypic culture model that mimics a preneoplastic tissue and contains mixtures of genetically marked (β-galactosidase), low-grade malignant keratinocytes (HaCaT-ras II-4) and normal human keratinocytes (NHKs) to monitor the fate and phenotype of these cells after treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA). In submerged culture, concentrations of 0.001-1 μg/ml TPA were shown to limit the growth of NHKs yet had no effect on growth of II-4 cells. TPA (0.001 μg/ml) was then added to organotypic cultures containing mixtures of NHK:II-4 cells at varying ratios to determine whether this agent could selectively stimulate clonal expansion of II-4 cells in a normal epidermal background. Immunofluorescence for β-galactosidase demonstrated that TPA caused a significant increase in the percentage of β-galactosidase-positive areas in 12:1 and 4:1 mixtures. This TPA-induced expansion of II-4 cells was associated with a marked decrease in proliferation of NHKs, suggesting that II-4 could selectively expand because of its growth advantage relative to NHKs. Clonal expansion of tumor cells was temporally linked to the decreased expression of filaggrin and keratin 1 expression in adjacent NHKs. These findings indicate that TPA may enable expansion of potentially malignant cells through the epigenetic modification of proliferation in NHKs and differentiation of NHK and II-4 cells.