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

Chromium (Cr) is a trace element required for life. Biological activities o f 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 C r. For example, Cr (VI) is classified as a metal carcinogen [1], but Cr (II I) is widely used as a nutritional supplement [2, 3]. Establishment of a ge ne expression profile for Cr-induced cellular response is necessary to faci litate investigation of the biological activities of Cr. In the present stu dy, a large-scale gene expression analysis was conducted using RNA of human lung epithelial cells after in vitro exposure to Cr (VI). Utilizing high-d ensity oligonucleotide arrays representing 2400 genes, we observed that exp ression of 150 genes was up-regulated, and that of 70 genes were down-regul ated by Cr (VI). Functional analysis of these responsive genes led to an ou tline of potential biological activities of Cr in six aspects. The gene exp ression profile reveals that Cr may involves in redox stress, calcium mobil ization, energy metabolism, protein synthesis, cell cycle regulation and ca rcinogenesis in the cell. The results provide a critical clue for understan ding molecular mechanisms of the biological activities of Cr.