Transformed human bronchial epithelial cells (beas-2b) alter the growth and morphology of normal human bronchial epithelial cells in vitro

Normal human bronchial epithelial cells (BE) and adenovirus-12 SV40 hybrid virus transformed, non-tumorigenic human bronchial epithelial cells (BEAS-2B) were cultured for 7 days in a serum free hormone supplemented medium. BE cells after 3 days in culture were exposed to conditioned medium (CM_t) from confluent BEAS-2B cells. By day 7, CM_t-treated BE cells exhibited a lower colony forming efficiency (CFE), fewer cells per colony, and a reduced mitotic index (MI) and BrdU (bromodeoxyuridine) labeling index. CM_t also enhanced the expression of a terminally differentiated squamous phenotype in BE cells. Cell free lysates from BEAS-2B cells (CFL_t) had effects similar to CM_t on the MI and morphology of BE cells. In contrast, CM_t and CFL_t did not inhibit the growth, or alter the morphology of BEAS-2B cells. Conditioned medium from BE cells (CM_n) did not reduce the growth of BEAS-2B cells, and had little effect on the morphology of BE cells. In co-culturesAbbreviations BE normal bronchial epithelial cells - BEAS-2B adenovirus-12 SV40 hybrid virus transformed bronchial epithelial cells - CM_n conditioned medium from BE cells - CM_t conditioned medium from BEAS-2B cells - CF_n cell free lysate from BE cells - CFL_t cell free lysate from BEAS-2B cells - BrdU bromodeoxyuridine - KGM keratinocyte growth medium - TGF- transforming growth factor type - NCI-LHC National Cancer Institute-Laboratory of Human CarcinogenesisContribution No. 2801 from the Pathobiology Laboratory, University of Maryland.