Gene expression profile in response to chromium-induced cell stress in A549 cells

Chromium (Cr) is a trace element required for life. Biological activities of Cr are complicated and remain to be fully investigated. It is known that the valence of Cr plays an important role in the biological activities of Cr. For example, Cr (VI) is classified as a metal carcinogen [1], but Cr (III) is widely used as a nutritional supplement [2,3]. Establishment of a gene expression profile for Cr-induced cellular response is necessary to facilitate investigation of the biological activities of Cr. In the present study, a large-scale gene expression analysis was conducted using RNA of human lung epithelial cells after in vitro exposure to Cr (VI). Utilizing high-density oligonucleotide arrays representing 2400 genes, we observed that expression of 150 genes was up-regulated, and that of 70 genes were down-regulated by Cr (VI). Functional analysis of these responsive genes led to an outline of potential biological activities of Cr in six aspects. The gene expression profile reveals that Cr may involves in redox stress, calcium mobilization, energy metabolism, protein synthesis, cell cycle regulation and carcinogenesis in the cell. The results provide a critical clue for understanding molecular mechanisms of the biological activities of Cr.