Application of DNA microarrays in pharmacogenomics and toxicogenomics

Many drugs or xenobiotics can induce specific or nonspecific cellular signal transduction events that activate various physiologic and pharmacologic responses including homeostasis, proliferation, differentiation, apoptosis, and necrosis. To minimize the insults caused by these xenobiotics, tissues and organs are equipped with protective mechanisms that either pump drugs out of the cells (e.g., the multidrug-resistant, mdr, family of proteins) or increase the level of detoxifying enzymes such as phase I and II drug-metabolizing enzymes (DMEs), after exposure to xenobiotics. This review discusses the molecular analysis of pharmaco- or toxicogenomic gene expression profiles following exposure to cancer chemotherapeutic and chemopreventive agents. We present the development of DNA microarray technology and its use in expression profiling of possible signal transduction events elicited by these compounds, and its potential future applications in drug discovery and development in the pharmaceutical industry.