title: Immortalized connexin43 knockout cell lines display a subset of biological properties associated with the transformed phenotype.
abstract: Immortalized cells from embryonic connexin43 knockout mice (Cx43-/-) and homozygous littermates (Cx43+/+) were cloned and characterized to determine whether the absence of Cx43 function would induce observable phenotypic changes. Cells of the Cx43+/+ clones expressed Cx43 and engaged in gap junctional communication with 10-12 neighboring cells. The Cx43-/- cells were devoid of Cx43 and communicated to less than 1 cell. Electrophysiological analysis indicated that the Cx43-/- cells communicated through Cx45 channels from 8-80-fold less than did the Cx43+/+ subclones, which seemed to communicate through Cx43 and Cx45 channels. The Cx43-/- clones grew at faster rates and to higher saturation densities, had a more spindly morphology, were more refractile, and adhered less well to the substratum than did the Cx43+/+ clones. Reintroducing the Cx43 gene into the Cx43-/- clones resulted in three subclones that communicated to 3-4 cells. Partial restoration of gap junctional communication in the three subclones was accompanied by reduced growth rates and saturation densities (2-fold compared to that of parental Cx43-/- clones) but no reversions in morphology or cell-substratum adhesion. The increased growth rates and saturation densities, altered morphology, and decreased cell adhesion displayed by the Cx43-/- clones reflect a subset of the properties of transformed cells. These studies advance the hypothesis that loss of Cx43 function during development may cause cells to acquire a preneoplastic condition.
authors.affiliation: Molecular Carcinogenesis Program, Cancer Research Center, University of Hawaii at Manoa 96813, USA.
authors.forename: K D
authors.initials: KD
authors.lastname: Martyn
authors.forename: W E
authors.initials: WE
authors.lastname: Kurata
authors.forename: B J
authors.initials: BJ
authors.lastname: Warn-Cramer
authors.forename: J M
authors.initials: JM
authors.lastname: Burt
authors.forename: E
authors.initials: E
authors.lastname: TenBroek
authors.forename: A F
authors.initials: AF
authors.lastname: Lau
mesh_terms: D000818:Animals; D002455:Cell Division / Q000235:genetics; D002461:Cell Line, Transformed; D002999:Clone Cells; D018031:Connexin 43 / Q000096:biosynthesis / Q000235:genetics*; D017629:Gap Junctions / Q000235:genetics / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D010641:Phenotype; D012313:RNA / Q000032:analysis / Q000096:biosynthesis; D013997:Time Factors; D014162:Transfection
chemical_list: D018031:Connexin 43; D012313:RNA