Inhibition of gap junctional intercellular communication and delocalization of the cell adhesion molecule E-cadherin by tumor promoters.
The effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) and benzoyl peroxide (BoP) on gap junctional intercellular communication (GJIC) and the amount and localization of E-cadherin was studied in initiated mouse epidermal cells (3PC) and in carcinoma cells (CA3/7) originating from the same cell type. In addition, the localization and phosphorylation of connexin43 was studied in both cell lines and in primary keratinocytes. GJIC inhibition by TPA and BoP was stronger in primary keratinocytes compared with both cell lines. BoP strongly decreased the amount of E-cadherin protein and the level occurring in the membranes in both cell lines, whereas TPA caused a translocation of E-cadherin from the membrane towards the cytosol, without decreasing the total amount of E-cadherin present. The effect of both tumor promoters on connexin43 phosphorylation and localization was agent as well as cell dependent. These results show for the first time that tumor promoters can decrease the quantity and membrane localization of E-cadherin in different cell types.
Jansen
L A
LA
Department of Product Quality and Safety, Agrotechnological Research Institute (ATO-DLO), Wageningen, The Netherlands.
Mesnil
M
M
Jongen
W M
WM
D000818:Animals; D001585:Benzoyl Peroxide / Q000494:pharmacology*; D015820:Cadherins / Q000187:drug effects / Q000378:metabolism*; D002273:Carcinogens / Q000494:pharmacology*; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology*; D015603:Keratinocytes / Q000187:drug effects / Q000502:physiology; D051379:Mice; D010766:Phosphorylation; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D015820:Cadherins; D002273:Carcinogens; D018031:Connexin 43; D013755:Tetradecanoylphorbol Acetate; D001585:Benzoyl Peroxide