dieldrin and Teratoma

Inhibition of intercellular communication, as measured by metabolic cooperation between 6-thioguanine-sensitive and 6-thioguanine-resistant Chinese hamster V79 cells, has been previously shown to be correlated with a large variety of known tumor promoters, including some of the organochlorine pesticides. Since further evidence concerning the effects of those known or suspected animal tumor promoters on human cells is needed, three organochlorine pesticides, dieldrin, aldrin, and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), were tested for their ability to inhibit metabolic cooperation between 6-thioguanine-sensitive (6TGs, HTP3-4) and 6-thioguanine-resistant (6TGr, HTXTG-1) human teratocarcinoma cells. Similar to the effect of the known mouse skin tumor promoter 12-tetradecanoyl phorbol-13-acetate (TPA), all three pesticides inhibited gap junctional intercellular communication within a noncytotoxic dose range. The dose-response curves of these chemicals were similar to those of other known tumor promoters on Chinese hamster V79 cells. In addition, the transfer of [3H]uridine between teratocarcinoma cells in contact was reduced after pesticide treatment.

Topics: Aldrin; Cell Communication; Cell Line; DDT; Dieldrin; Humans; Insecticides; Intercellular Junctions; Kinetics; Teratoma; Tritium; Uridine

Gap junction-mediated communication between contiguous cells has been implicated in the regulation of cell proliferation and differentiation. This report describes a new technique to measure cell-cell communication, gap fluorescence redistribution after photobleaching, which is based on the diffusion-dependent return of 6-carboxyfluorescein-mediated fluorescence in a photobleached cell that is in contact with other fluorescently labeled cells. Fluorescence recovery rates are interpreted as dye transport across gap junctions. Results of experiments on normal human fibroblasts and human teratocarcinoma cells show that this technique can measure rapid dye transfer and detect inhibition of communication (between teratocarcinoma cells) by the tumor promoters 12-O-tetradecanoyl-phorbol-13-acetate and the pesticide dieldrin.

Topics: Cell Communication; Dieldrin; Fibroblasts; Fluoresceins; Humans; Intercellular Junctions; Microscopy, Fluorescence; Teratoma; Tetradecanoylphorbol Acetate

Topics: Abnormalities, Drug-Induced; Animals; Animals, Newborn; Antifungal Agents; Chickens; Chlordan; Cholinesterase Inhibitors; Cricetinae; DDT; Dieldrin; Dogs; Drug Synergism; Ducks; Eggs; Embryo, Mammalian; Embryo, Nonmammalian; Extraembryonic Membranes; Female; Fetal Death; Fetus; Genetics; Guinea Pigs; Haplorhini; Herbicides; Hydrocarbons, Halogenated; Insecticides; Maternal-Fetal Exchange; Mice; Milk, Human; Neurologic Manifestations; Parathion; Pesticides; Phosphates; Pregnancy; Rabbits; Rats; Teratoma