PHENOTYPE AND DIFFERENTIATION POTENTIAL OF A NOVEL RAT TRACHEAL EPITHELIAL-CELL LINE

In this report we described the establishment and characterization of a continuous rat tracheal epithelial (RTE) cell line spontaneously der ived from secondary RTE cell cultures. Designated SPOC1, this cell lin e is nontumorigenic and maintains a diploid karyotype with specific, n onrandom chromosomal alterations involving chromosomes 1, 3, and 6. SP OC1 cells demonstrate decreased requirements for peptide growth factor s, compared with primary RTE cells. Upon inoculation into denuded rat tracheas, which are then implanted into syngeneic hosts, SPOC1 cells i nitially form a stratified squamous epithelium, which becomes less str atified with time and forms glandlike invaginations into the surroundi ng lamina propria. No evidence of ciliated cell differentiation is det ected. The epithelium formed by SPOC1 cells in tracheal grafts reacts with antibodies specific for keratin 14, 13, and 19 (but not keratin 1 8) at both early and late time points, although the localization of an tibody staining changes as the epithelium becomes less stratified with time. The suprabasal epithelial cells become positive for alcian blue -periodic acid-Schiff staining at later time points. The near-normal k aryotype and differentiation potential of SPOC1 cells make this cell l ine a unique window into early changes occurring during immortalizatio n of airway epithelial cells and will allow studies of relationships b etween differentiation state and neoplastic transformation.