EFFECT OF '-(2,2,2-TRICHLOROETHYLIDENE)-BIS(4-CHLOROBENZENE) (DDT) ONGAP JUNCTIONAL INTERCELLULAR COMMUNICATION AND MORPHOLOGICAL TRANSFORMATION OF SYRIAN-HAMSTER EMBRYO CELLS
Le. Roseng et al., EFFECT OF '-(2,2,2-TRICHLOROETHYLIDENE)-BIS(4-CHLOROBENZENE) (DDT) ONGAP JUNCTIONAL INTERCELLULAR COMMUNICATION AND MORPHOLOGICAL TRANSFORMATION OF SYRIAN-HAMSTER EMBRYO CELLS, Chemico-biological interactions, 90(1), 1994, pp. 73-85
The organochlorine insecticide 1'-(2,2,2-trichloroethylidene)bis(4-chl
orobenzene) (DDT) did not induce or promote induction of morphological
transformation in Syrian hamster embryo (SHE) cells, but it was a pot
ent inhibitor of gap junctional intercellular communication (GJIC). Th
e kinase inhibitor staurosporine did not affect DDT induced inhibition
of GJIC, although it has been shown to decrease the inhibitory effect
of 12-O-tetradecanoylphorbol-13-acetate (TPA) on GJIC. In addition, p
retreatment with TPA made the cells refractory to further TPA induced
inhibition of GJIC, while they remained sensitive to DDT. Thus, DDT an
d TPA inhibit GJIC through different mechanisms. Elevation of cellular
cyclic adenosine monophosphate (cAMP) level by exposure to forskolin
counteracted the inhibitory effect of DDT similar to that observed for
TPA. Continuous exposure to DDT at concentrations near the effective
concentration (50%) value (EC(50) value) resulted in a slight recovery
of GJIC following the initial inhibition. This recovery was not accom
panied by the cells becoming refractory to further DDT induced inhibit
ion of GJIC. The recovery of GJIC after removal of the DDT containing
medium seemed to be related to a reduction in the amount of cell-assoc
iated DDT.