Close relationship between modulation of serum-induced stimulation of DNA synthesis and changes in gap-junctional intercellular communication in quiescent 3T3-L1 cells caused by cyclic AMP and the tumor-promoting phorbol ester TPA.
Involvement of gap-junctional intercellular communication in the stimulation of growth was investigated in quiescent 3T3-L1 cells. When the cells in monolayer were growth-arrested by culture in a low concentration of calf serum, addition of dibutyryl cyclic AMP enhanced dye-coupling and suppressed the enhancement of DNA synthesis, induced by calf serum, in quiescent cells. 12-O-Tetradecanoylphorbol-13-acetate (TPA) suppressed dye-coupling in quiescent cells and enhanced DNA synthesis in both quiescent and serum-treated cells. When about 5000 cells were cultured in contact to form a colony, growth arrest of the cells was observed in the central region of such colonies rather than in the peripheral region, but addition of calf serum induced DNA synthesis in the cells in both the peripheral and central regions of the colonies. Addition of TPA enhanced serum-induced DNA synthesis in the cells in the central region of colonies rather than in the peripheral region. These results suggest that the ability of quiescent cells to escape from growth arrest is inversely correlated to the extent of gap-junctional intercellular communication.
Shiba
Y
Y
Department of Oral Physiology, Hiroshima University School of Dentistry, Japan.
Sasaki
Y
Y
Hirono
C
C
Kanno
Y
Y
D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D003994:Bucladesine / Q000494:pharmacology*; D002450:Cell Communication / Q000187:drug effects*; D002453:Cell Cycle / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media; D000242:Cyclic AMP / Q000502:physiology*; D004261:DNA Replication / Q000187:drug effects*; D007365:Intercellular Junctions / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D051379:Mice; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D003470:Culture Media; D003994:Bucladesine; D000242:Cyclic AMP; D001973:Bromodeoxyuridine; D013755:Tetradecanoylphorbol Acetate