DOK, a cell line established from human dysplastic oral mucosa, shows a partially transformed non‐malignant phenotype

Abstract

There are many reports of cell lines being established from human oral squamous-cell carcinomas but apparently none of cell lines from dysplastic or "pre-malignant" oral mucosa. We describe here the isolation and characterization of a cell line, DOK (dysplastic oral keratinocyte), from a piece of dorsal tongue showing epithelial dysplasia. The tissue was obtained from a 57-year-old man who was a heavy smoker prior to the appearance of a white patch on his tongue. Eleven years later a squamous-cell carcinoma developed at the site and was excised. Subsequently the remaining dysplasia was removed, and it was from a piece of this that the primary cell cultures which eventually gave rise to DOK were initiated. The DOK line has been single-cell cloned and is apparently immortal. It grows in the absence of 3T3 feeder cells, is anchorage-dependent for growth and is non-tumorigenic in nude mice. The keratin profile of the cells shows a striking similarity to that of the original tongue dysplasia. The karyotype of DOK is aneuploid and complex. By PCR and oligonucleotide hybridization on dot blots, codons 12, 13 and 61 of Ha-ras, Ki-ras and N-ras in DNA extracted from DOK cells were shown to be normal. Immunohistochemistry showed no abnormal, i.e., elevated expression of the onco-suppressor protein p53. Because of its origin and partially transformed phenotype, DOK presents an opportunity to study whether specific carcinogens associated with tobacco and areca nut can cause malignant transformation of oral keratinocytes in vitro.

Laminin‐γ2 overexpression in head‐and‐neck squamous cell carcinoma

“…However, we did not detect ␥2 expression in normal or premalignant tissue specimens, and it is perhaps more likely that DOK cells are indeed carcinoma cells as they were derived from epithelium immediately adjacent to an invasive HNSCC and harbor a mutation within p53. 30 In a previous study, 34 we reported that p53 mutations were absent in cells derived from premalignant oral lesions, implying that this is not an early event in HNSCC tumor development. Indeed, DOK cells show other features of a transformed phenotype compared to other premalignant cells, including aneuploidy, cellular immortality and a reduced serum and factor requirement for in vitro growth.…”

“…Human epithelial cell lines SCC25, 26 T45, 27 BICR16, 28 HN6, HN12, HN13, HN26 and HN30, 29 derived from HNSCC, and DOK, derived from a premalignant oral lesion, 30 were cultured in DMEM supplemented with 10% FBS and 0.4 g/ml hydrocortisone on a feeder layer of lethally irradiated Swiss-3T3 fibroblasts. Feeder cells were removed prior to subculturing or RNA preparation by standard procedures.…”

Identification of Two Distinct Carcinoma-Associated Fibroblast Subtypes with Differential Tumor-Promoting Abilities in Oral Squamous Cell Carcinoma

“…23) obtained from European Collection of Cell Cultures were suspended in 50 mL of growth factor-reduced matrigel (BD Biosciences), and inoculated alone (n ¼ 6) or together with 10 5 fibroblasts of the strains NF5 (n ¼ 6), CAF1 (n ¼ 6), or CAF5 (n ¼ 6) subcutaneously on the back of 12-week-old nonobese diabetic/severe combined immunodeficient (NOD/SCID) IL2rg(null) mice (The Jackson Laboratory). Tumor incidence and development (volume) was assessed at every 3 days.…”

Expression of p8 in Human Oral Squamous Cell Carcinoma

“…Human Cell Lines and Culture Conditions SCC25 and OSC2 (OSCC), and DOK (dysplastic oral keratinocytes), and A818-6 (Human Pancreatic Adenocarcinoma) human cell lines have been published [15][16][17][18] and were initially obtained from American Type Culture Collection. The human oral keratinocyte (HOK) whole lysate was purchased from ScienCell TM Research Laboratories (cat.…”