For the study, the researchers analyzed the downstream genomic targets of the transcription factor Nrf2 (Nuclear factor E2 p45-related factor 2), which scientists previously knew was activated in response to anticancer agents such as sulforaphane. The transcription factor, Nrf2, in response to cancer preventive agents, turns on genes and pathways inside the cell, whose products help in ridding the body of carcinogens.
"Carcinogens mutate the DNA in genes, which leads to cancer. Now, we know that sulforaphane present in broccoli can turn an extensive network of genes and pathways, which can annihilate a broad spectrum of carcinogens," said Shyam Biswal, PhD, assistant professor of environmental health sciences at the Johns Hopkins Bloomberg School of Public Health.
"With this study we've identified the specific genes regulated in response to a promising chemopreventive agent, which tells us how the process of cancer chemoprevention is occurring and provides us with a novel strategy for evaluating potential cancer preventive agents in future," explained Dr. Biswal.
Dr. Biswal and his colleagues studied the gene profile of small intestines of mice to identify the genes regulated by Nrf2. The researchers treated groups of mice with sulforaphane and compared the effects to control groups in which the Nrf2 gene was knocked off. "In summary, this study expands the scope of the positive, coordinated regulation of a wide variety of cellular defense proteins by Nrf2 and underscores the potential of Nrf2 activation as a strategy for achieving cancer chemoprevention," said Dr. Biswal.
"Identification of Nrf2-regulated Genes Induced by the Chemopreventive Agent Sulforaphane by Oligonucleotide Microarray" was written by Rajesh K. Thimmulappa, Kim H. Mai, Sorachai Srisuma, Thomas W. Kensler, Masayuki Yamamoto, and Shyam Biswal. It is published in the September 15, 2002 edition of "Cancer Research."
The study was supported by grants from the Maryland Cigarette Restitution Fund and the American Cancer Society.
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Journal
Cancer Research