Relationship between toxicity of selected insecticides and expression of stress proteins (HSP, GRP) in cultured human cells: effects of commercial formulations versus pure active molecules.

Three carbamate (formetanate, methomyl, pyrimicarb) and one pyrethroid (bifenthrin) insecticides were investigated both as pure chemicals and as commercial formulations in order to unveil possible toxic effects of additives and solvents present in the commercial formulations and to evaluate the cellular stress response as a defense mechanism. Toxic effects were evaluated on A549 cells, derived from a human lung carcinoma, by measuring (1) threshold concentrations leading to a decrease of the growth rate (LOEC), (2) sublethal concentrations (SC) which arrested growth without killing the cells, and (3) expression levels of several stress proteins, i.e.

Expression of stress-related genes in a cadmium-resistant A549 human cell line.

This study was designed to explain the basis for Cd-acquired tolerance of A549 cells cultured in the presence of Cd. Thirty-day exposure of cultured human pneumocytes (A549 cell line) to 10 microM Cd was previously found to induce an acquired resistance persisting over several weeks of culture. Moreover, these Cd-resistant cells (R-cells) were found to proliferate faster than controls.