Alterations of intercellular communication associated with the transformation of C3H/10T1/2 cells

Cultures of C3H/10T1/2 mouse embryo cells were treated in accordancewith several treatment regimens that induced the focal growthof morphologically transformed cells. Inter cellular communicationbetween focus cells, and between focus and monolayer cells,was examined in late stages of transformation experiments bymicroinjection of Lucifer yellow dye into cells and observationof dye transfer to surrounding cells. Transformed foci producedby treatment with 3-methylcholanthrene, by initiation with N-methyl-N'nitro-N-nitrosoguanidine (MNNG) and promotion with 12-O-tetradecanoylphorbol-13-acetate(TPA), or by initiation with MNNG and promotion with 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD) were studied. These included focus types thought to possesstumongenic potential (Types II and III) and those believed tolack such potential (Type I). Cells within all focus types exhibitedonly limited communication with each other or with surroundingmonolayer cells. In contrast, microinjection of monolayer cellstypically resulted in dye transfer to an average of {small tilde}50other monolayer cells. The presence of the tumor promoters TPAor TCDD did not alter intercellular communication between monolayercells. These studies demonstrate that alterations in intercellularcommunication are evident during the growth of transformed foci.These changes are relatively independent of both the treatmentregimen used to produce foci and the presumed oncogenic potentialof different focus types.