Calcium dependence of chemical carcinogen induced morphological transformation of Syrian hamster embryo cells.
The effect of extracellular calcium upon carcinogen induced morphological transformation was evaluated in Syrian hamster embryo cells. Reduction in [Ca2+] from 1.8 mM to 0.2 mM throughout the 6 days between exposure of the cells to 2.5 microgram benzo [a]pyrene (BP)/ml and examination of the cells for transformation inhibited both cell proliferation and transformation as measured by the frequencies of colony formation and morphological transformation. The transformation frequency among surviving cells, i.e. frequency/cell colony, however, was nearly equivalent indicating that the inhibition of transformation largely resulted from inhibition of cell colony formation. Proliferation and transformation were unaffected when [Ca2+] was reduced to 0.2 mM on days 3-6. Reduction to 0.01 mM Ca2+ during the same period, however, completely abolished transformation by BP, UV-irradiation or n-acetoxyacetylaminofluorene (AcAAF) without reducing cell proliferation. Thus, the expression of morphological transformation in newly transformed hamster cells is dependent upon extracellular [Ca2+] to a greater degree than is cell proliferation.
D000099:Acetoxyacetylaminofluorene / Q000494:pharmacology; D000818:Animals; D001580:Benzopyrenes / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D002452:Cell Count; D002471:Cell Transformation, Neoplastic / Q000187:drug effects* / Q000528:radiation effects; D002478:Cells, Cultured; D006224:Cricetinae
D001580:Benzopyrenes; D000099:Acetoxyacetylaminofluorene; D002118:Calcium