Isolation and characterization of an immortalized oral keratinocyte cell line of mouse origin.
OBJECTIVE
To establish an oral epithelial cell line of mouse origin for molecular and biochemical assays.


METHODS
Epithelial cells were isolated from the oral cavity of adult mice and established as a spontaneously immortalized cell line in culture, designated immortalized oral keratinocyte cells (IMOK cells). The cells were then characterized for growth characteristics, differentiation potential, karyotype, transfectability, susceptibility to viral infection and responses to siRNA.


RESULTS
The IMOK cells exhibit robust growth in both serum-containing and serum-free medium for at least 100 population doublings. IMOK cells have a near diploid karyotype, express keratinocyte marker proteins and can be induced to undergo differentiation by the addition of high levels of calcium to the medium. The differentiation process is characterized by morphological changes and by the induction of oral epithelium specific differentiation marker proteins such as K4 and K13. Transient transfection analyses reveal that IMOK cells are highly transfectable and that several promoters of epithelial cells are active in these cells. Moreover, upon differentiation with calcium, there is an up-regulation of differentiation-specific K4 and Elf5 promoter activity. Finally, we show that the oral keratinocytes are also amenable to infection with retroviruses and to siRNA-based knockdown of gene expression.


CONCLUSIONS
Our study is the first to establish an immortalized oral keratinocyte cell line of murine origin that can recapitulate the oral epithelium differentiation program and thus could serve as a useful tool for toxicological and molecular analyses of the oral tissue.
Parikh
Neha
N
Department of Biochemistry, State University of New York at Buffalo, Buffalo, NY 14214, USA.
Nagarajan
Priyadharsini
P
Sei-ichi
Matsui
M
Sinha
Satrajit
S
Garrett-Sinha
Lee Ann
LA
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D002461:Cell Line, Transformed / Q000166:cytology*; D003470:Culture Media; D004847:Epithelial Cells / Q000166:cytology / Q000821:virology; D005260:Female; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D007621:Karyotyping; D015603:Keratinocytes / Q000166:cytology* / Q000821:virology; D007633:Keratins / Q000378:metabolism; D051379:Mice; D009061:Mouth Mucosa / Q000166:cytology* / Q000821:virology; D011401:Promoter Regions, Genetic; D034741:RNA, Small Interfering / Q000235:genetics; D012192:Retroviridae Infections / Q000378:metabolism / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014162:Transfection
D003470:Culture Media; D034741:RNA, Small Interfering; D007633:Keratins; D002118:Calcium