Arsenic-induced Changes in L2 Cells

Arsenic is a carcinogen that is known to induce cell transformation and tumor formation. Although studies have been performed to examine the modulation of signaling molecules caused by arsenic exposure, the molecular mechanisms by which arsenic causes cancer are still unclear. We hypothesized that arsenic alters gene expression leading to carcinogenesis in the lung. In this study, we examined global gene expression in response to 0.75 µM arsenic treatment for 1-7 days in a rat lung epithelial cell line (L2) using an in-house 10k rat DNA microarray. One hundred thirty one genes were identified using the one-class statistical analysis of microarray (SAM) test. Of them, 33 genes had a fold change of ≥ 2 at least between two time points. These genes were then clustered into 5 groups using K-means cluster analysis based on their expression patterns. Seven selected genes, all associated with cancer, were confirmed by real-time PCR. These genes have functions directly or indirectly related to metabolism, glycolysis, cell proliferation and differentiation, and regulation of transcription, all of which may be involved in neoplastic transformation of cells. Our findings provide important insight for the future studies of arsenic-mediated lung cancer. Keywords: Lung, aresenic, L2, micorarray L2 cells were exposed with 0.75 uM of arsenite for 0, 1, 3, 5, and 7 days (C, D1, D3, D5 and D7). The samples were arranged for hybridization using a loop design. For each paired sample, dye flip and three biological replications were performed for each sample.