title: Immortalization of normal human gingival keratinocytes and cytological and cytogenetic characterization of the cells.
abstract: Most in vitro studies of oral carcinogenesis in human cells are carried out with oral keratinocytes immortalized by human papillomavirus type 16 DNA. However, because various etiological factors for oral cancer are known, it is important to establish new human keratinocyte cell lines useful for studying the mechanism of oral carcinogenesis. Normal human gingival keratinocytes in secondary cultures grown in serum-free medium were either transfected with origin (-) SV40 DNA or sequentially transfected with origin (-) SV40 DNA and human c-fos. The transfected cells were continually passaged and analyzed for cytological and cytogenetic characterizations. Four immortal cell lines were grown for over 1100 days in culture and maintained a vigorous growth for over 250 population doublings. They expressed SV40 T antigen, cytokeratins 8 and 18, and E-cadherin, and overexpressed the c-Fos protein. The immortal cell lines had telomerase activity but lacked transformed phenotypes on soft agar or in nude mice. Each cell line had nonrandom chromosomal abnormalities and minisatellite alterations. One of the immortal cell lines, NDUSD-1, retained the capability to deposit calcium, which was also demonstrated in normal human gingival keratinocytes by alizarin red staining, indicating the possibility that NDUSD-1 cells may retain some natural characteristics of normal gingival keratinocytes. Because the oral ectoderm plays an important role in tooth development, these immortal cell lines may be useful in various experimental models for investigations of oral biology and oral carcinogenesis.
authors.affiliation: Department of Pharmacology, The Nippon Dental University, School of Life Dentistry at Tokyo, Tokyo, Japan.
authors.forename: Chikahiro
authors.initials: C
authors.lastname: Kubo
authors.forename: Takeo W
authors.initials: TW
authors.lastname: Tsutsui
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Tamura
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Kumakura
authors.forename: Takeki
authors.initials: T
authors.lastname: Tsutsui
mesh_terms: D000818:Animals; D000880:Anthraquinones; D000952:Antigens, Polyomavirus Transforming / Q000032:analysis; D015820:Cadherins / Q000032:analysis; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002461:Cell Line, Transformed; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000473:pathology*; D002472:Cell Transformation, Viral / Q000235:genetics; D002869:Chromosome Aberrations; D004396:Coloring Agents; D004279:DNA, Viral / Q000235:genetics; D016762:Genes, fos / Q000235:genetics; D005881:Gingiva / Q000166:cytology*; D006801:Humans; D007621:Karyotyping; D053538:Keratin-18 / Q000032:analysis; D053533:Keratin-8 / Q000032:analysis; D015603:Keratinocytes / Q000166:cytology* / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D018598:Minisatellite Repeats / Q000235:genetics; D010641:Phenotype; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis; D013539:Simian virus 40 / Q000235:genetics / Q000276:immunology; D019098:Telomerase / Q000378:metabolism; D013997:Time Factors; D014162:Transfection / Q000379:methods
chemical_list: D000880:Anthraquinones; D000952:Antigens, Polyomavirus Transforming; D015820:Cadherins; D004396:Coloring Agents; D004279:DNA, Viral; D053538:Keratin-18; D053533:Keratin-8; D016760:Proto-Oncogene Proteins c-fos; C010078:alizarin; D019098:Telomerase; D002118:Calcium