A new study has reported a mechanism of action by which cadmium influences gene expression in triple negative (ER-/PR-/HER2-) breast cancer cells. Cadmium, a heavy metal, is known to regulate gene expression in normal and cancerous human cells. The authors previously showed cadmium exerts a cytotoxic effect on MDA-MB231 triple negative human breast cancer cells. This effect is characterized by the onset of a kind of programmed death, impairment of mitochondrial activity, and dramatic changes in gene expression. Each gene encodes a unique protein that performs a specialized function in cells. Cells use a two-step process of transcription and translation to read the gene and produce its protein. Gene transcription is the process by which genetic information is copied from DNA to RNA. This is followed by translation, in which the RNA is read and a specific protein is produced. In the current study, the authors used a variety of techniques to examine the changes in transcription exerted by cadmium.

The results demonstrated that treating MDA-MB231 cells for 96 hours with cadmium chloride was shown to selectively down-regulate astrocyte-elevated gene-1 (AEG-1) and reduce the accumulation of its protein product. The AEG-1 gene has been shown to have a functional role in several important aspects of tumor progression, including invasion, metastasis, and chemoresistance. Overexpression of AEG-1 is frequently observed in breast cancer. The authors comment that the study results provide a new contribution to the comprehension of the intracellular molecular mechanisms implicated in cadmium-breast cancer cell interactions.