Physiol. Genomics 38: 386-401, 2009.
First published June 23, 2009; doi:10.1152/physiolgenomics.00083.2009
1094-8341/09 $8.00
Received 12 May 2009;
accepted in final form 13 June 2009.
Physiological Genomics 38:386-401 (2009)
1094-8341/09 $8.00 © 2009 American Physiological Society
Physiological and toxicological transcriptome changes in HepG2 cells exposed to copper
Min Ok Song
1,
Jianying Li
2 and
Jonathan H. Freedman
1
1 Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
2 Biostatistics Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
Copper is an essential trace element; however, at supraphysiological levels, it can be extremely toxic. Microarray data from HepG2 cells exposed to 100, 200, 400, and 600 µM copper for 4, 8, 12 and 24 h were generated and analyzed. Principal components, K-means, and hierarchical clustering, interactome, and pathway mapping analyses indicated that these exposure conditions induce physiological and toxicological changes in the HepG2 transcriptome. As a general trend, when the level of toxicity increases, the number and diversity of affected genes, Gene Ontology categories, regulatory pathways, and complexity of interactomes increase. Physiological responses to copper include transition metal ion binding and responses to stress/stimulus, whereas toxicological responses include apoptosis, morphogenesis, and negative regulation of biomolecule metabolism. The global gene expression profile was overlaid onto biomolecular interaction networks and signal transduction cascades using pathway mapping and interactome identification. This analysis indicated that copper modulates signal transduction pathways associated with MAPK, NF-
B, death receptor, IGF-I, hypoxia, IL-10, IL-2, IL-6, EGF, Toll-like receptor, protein ubiquitination, xenobiotic metabolism, leukocyte extravasation, complement and coagulation, and sonic hedgehog signaling. These results provide insights into the global and molecular mechanisms regulating the physiological and toxicological responses to metal exposure.
signal transduction pathways; interactome; Gene Ontology; transition metal; Cytoscape
Copyright © 2009 by the American Physiological Society.