title: The feeder layer-mediated extended lifetime of cultured human skin keratinocytes is associated with altered levels of the transcription factors Sp1 and Sp3.
abstract: Primary cultured epithelial cells that are used for basic research are often cultivated on plastic whereas those used for clinical purposes are usually cultured in the presence of a feeder layer. Here, we examined the influence of a feeder layer on the expression, affinity and DNA binding ability of the transcription factors, Sp1 and Sp3 in primary cultures of human skin keratinocytes. Co-culturing both newborn and adult skin keratinocytes with lethally irradiated 3T3 cells as a feeder layer contributed to maintain the cell's morphological and growth characteristics and delayed terminal differentiation in vitro. 3T3 also stabilized the DNA binding properties of Sp1 without altering its transcription. Stimulation of Sp1/Sp3 expression appears to be mediated through cell-cell interactions and by factors secreted by 3T3. Thus, we propose that the feeder layer delay terminal differentiation of primary cultured skin keratinocytes by preventing extinction of transcription factors, like Sp1 and Sp3, which play pivotal functions in the cell cycle.
authors.affiliation: Oncology and Molecular Endocrinology Research Center, Québec, Canada.
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Masson-Gadais
authors.forename: Claudia
authors.initials: C
authors.lastname: Fugère
authors.forename: Claudie
authors.initials: C
authors.lastname: Paquet
authors.forename: Steeve
authors.initials: S
authors.lastname: Leclerc
authors.forename: Natalie R
authors.initials: NR
authors.lastname: Lefort
authors.forename: Lucie
authors.initials: L
authors.lastname: Germain
authors.forename: Sylvain L
authors.initials: SL
authors.lastname: Guérin
mesh_terms: D016475:3T3 Cells; D000328:Adult; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002452:Cell Count; D049109:Cell Proliferation; D004268:DNA-Binding Proteins; D006801:Humans; D007231:Infant, Newborn; D015603:Keratinocytes / Q000378:metabolism*; D007633:Keratins / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D012867:Skin / Q000166:cytology; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D051705:Sp3 Transcription Factor / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D016329:Sp1 Transcription Factor; D051705:Sp3 Transcription Factor; D007633:Keratins