Studies of human bronchial epithelium in vitro: Changes of [Ca2+]i in relation to injury, growth and differentiation☆

Abstract The objectives of the present work included the study of the response of normal human bronchial epithelial (NHBE) cells to injury following treatment with several agents, especially those associated with tumour promotion. The effects of putative tumour promoters including 12- O -tetradecanoylphorbol acetate (TPA), a series of aldehydes, and H 2 O 2 on the regulation of cytosolic ionized calcium ([Ca 2+ ] i ) were compared with the effects of growth and squamous differentiation stimuli, including serum and transforming growth factor-β. The cells studied included primary cultures of NHBE cells and the BEAS-2B cell line, created by transformation of NHBE cells with the adenovirus 12-Simian virus 40 hybrid. The results indicate that, with several stimuli, the onset of terminal squamous differentiation is preceded by a rise in [Ca 2+ ] i . The results are interpreted in terms of a general hypothesis regarding the interaction between acute and chronic cell injury.