ENHANCEMENT OF GAP JUNCTIONAL INTERCELLULAR COMMUNICATION BY DIBUTYRYL-CYCLIC-AMP IN LUNG EPITHELIAL-CELLS

Reduced gap junctional intercellular communication (GJIC) occurs in ne oplastic cells and contributes to their phenotype. Cyclic AMP agonists inhibit lung cancer cell growth and enhance GJIC in other cell types, but little is known about their effects on lung epithelial cell gap j unctions. We have examined whether N-6,2'-O-dibutyryladenosine 3':5'-c yclic mono-phosphate (DBcAMP) affected GJIC, gap junction protein (con nexin43) expression, and the growth of non-transformed and neoplastic mouse lung epithelial cells. DBcAMP (0.01-1 mM) stimulated GJIC (assay ed by fluorescent dye microinjection) and connexin43 expression (asses sed by Northern and Western blotting) and reduced their proliferation. These results suggest an association between cAMP growth inhibition a nd enhanced GJIC in lung epithelial cells.