Curcumin does not alter the phorbol ester effect on cell-cell transfer of lucifer yellow CH

Curcumin, the dietary pigment responsible for the yellow color of curry, has been reported to be a potent inhibitor of tumor promotion in mouse epidermis. Since most tumor promoters inhibit cell-cell communication, we have examined the effect of curcumin on the reduction of gap junctional intercellular communication induced by the phorbol ester phorbol-12,13-dibutyrate (PDBu) in BALB/c 3T3 cells. Treatment of cells with 50 microM curcumin slightly inhibited the dye coupling evaluated by intercellular transfer of a fluorescent dye Lucifer Yellow CH; however, lower concentrations of curcumin did not affect the level of intercellular communication. Addition of 200 nM PDBu caused a rapid reduction of dye coupling, which was not altered by either pretreatment or simultaneous curcumin addition.