Short-term exposure to cadmium affects the expression of stress response- and apoptosis-related genes in immortalized epithelial cells from the human breast

It is known that cadmium (Cd) evokes cell responses that not only involve protective reactions against toxicity but also induces cell death. Increasing interest has been recently focused on the elucidation of the cellular and molecular aspects of Cd-dependent regulation of gene expression in different model systems. Here, we examined the effects of short-term (24h) exposure of immortalized non-tumoral HB2 cells from human breast epithelium to CdCl(2) at 50 microM concentration, corresponding to the IC(50) for this time of incubation. The possible occurrence of apoptosis-related events was evaluated via analysis of the physical state of the DNA and of the membrane localization of phosphatydilserine. We also checked the pattern of expression of stress response genes, such as those coding for heat shock proteins and metallothioneins, and of genes coding for factors and enzymes involved in the onset of apoptosis. Our results indicate that although metal treatment appears to induce a non-apoptotic type of cell death, Cd can be also regarded as an active transcriptional modulator for this cell line.