Nutritional and hormonal factors in the prevention of carcinogen-induced neoplastic development in vitro.
Cell cultures and in vitro oncogenic transformation offer a powerful tool for exploring conditions and compounds that may inhibit malignant transformation following exposure to environmental or therapeutic agents. We find, using rodent cell cultures, that retinoids inhibit radiation-induced transformation and eradicate the enhancing effect of tumor promotors. These protective effects of the retinoids are not mediated at a chromosomal level but are reflected at the cell membrane level via the membrane-associated transport enzyme Na/K-ATPase. Using these systems, we also find that hypothyroid condition is protective and that thyroid hormone T3 is essential for the induction of both radiation-induced and chemically induced carcinogenesis, and thus may also play a crucial role in cancer induction in vivo.
D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D002478:Cells, Cultured; D006224:Cricetinae; D051379:Mice; D012854:Sister Chromatid Exchange / Q000187:drug effects; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis; D013755:Tetradecanoylphorbol Acetate; D013963:Thyroid Hormones / Q000494:pharmacology*; D014801:Vitamin A / Q000494:pharmacology*
D013963:Thyroid Hormones; D014801:Vitamin A; D000254:Sodium-Potassium-Exchanging ATPase; D013755:Tetradecanoylphorbol Acetate