Abstract
The formation of gap junction and the expression of E-cadherin were studied by immunocytochemistry in a cultured intestinal-407 (I-407) cell colonies. These cells scarcely expressed connexin 43 (Cx43) and E-cadherin at a non-stimulated condition. When the cells were stimulated with forskolin and Ro-20-1724, a strong correlation was found between immunocytochemical staining of E-Cadherin and that of Cx43 at cell-to-cell contact areas. The length of E-cadherin-positive contact areas increased with time in the stimulated condition. On the other hand, the number of gap junctional plaques in the E-cadherin-expressed areas increased significantly 2 to 8hr after the stimulation and remained the same level until 24hr. Both immunostainings were more intense in the central area of the colony than in the peripheral area. Since the administration of forskolin and Ro-20-1724 has been known to elevate cAMP level, these results suggest that (1) the expression of both E-cadherin and gap junctions in cell-to-cell contact is induced by the elevation of cAMP and (2) the effect of cAMP varies by the location of cells in the colony which may reflect the state of cell differentiation.
