RAPID AND REVERSIBLE INHIBITION OF JUNCTIONAL COMMUNICATION BY TUMOR PROMOTERS IN A MOUSE-CELL LINE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 43  (8) , 3614-3618
Abstract
Mouse epidermal HEL-37 cells rapidly transferred microinjected fluorescein between contacting cells. This transfer was strongly inhibited by tumor-promoting phorbol esters and mezerein but not by non-promoting derivatives. The onset of the inhibition occurred after 5-10 min of exposure to the test compound and was complete within 20 min. Using a wash-off procedure, inhibition of dye transfer by phorbol-12,13-dibutyrate was fully reversed by 100 min, after a lag of 40-60 min. The recovery of dye transfer competence was blocked by puromycin. Both 12-O-tetradecanoylphorbol-13-acetate and monensin caused elevated Na+ levels in HEL-37 cells, but the latter compound did not inhibit dye transfer. The promoter inhibition of transfer was not a consequence of a Na+-induced increase in cytoplasmic Ca2+ concentration.