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

Cultures of C3H/10T1/2 mouse embryo cells were treated in accordance with several treatment regimens that induced the focal growth of morphologically transformed cells. Intercellular communication between focus cells, and between focus and monolayer cells, was examined in late stages of transformation experiments by microinjection of Lucifer yellow dye into cells and observation of dye transfer to surrounding cells. Transformed foci produced by 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 possess tumorigenic potential (Types II and III) and those believed to lack such potential (Type I). Cells within all focus types exhibited only limited communication with each other or with surrounding monolayer cells. In contrast, microinjection of monolayer cells typically resulted in dye transfer to an average of approximately 50 other monolayer cells. The presence of the tumor promoters TPA or TCDD did not alter intercellular communication between monolayer cells. These studies demonstrate that alterations in intercellular communication are evident during the growth of transformed foci. These changes are relatively independent of both the treatment regimen used to produce foci and the presumed oncogenic potential of different focus types.