JOANNE R. LUPTON, Ph.D., is a Distinguished Professor, Regent’s Professor and University Faculty Fellow at Texas A&M University and holder of the William W. Allen Endowed Chair in Human Nutrition. She chaired the Macronutrients Panel for the Dietary Reference Intakes, Food and Nutrition Board, National Academy of Sciences, that determined the intake values for protein, carbohydrates, fats, fiber and energy and she also chaired the National Academy panel to determine the definition of dietary fiber. She was a member of the 2005 Dietary Guidelines Committee. Dr. Lupton spent one year at the Food and Drug Administration helping to develop levels of scientific evidence required for health claims, and is currently on the FDA Food Advisory Committee. She is a lifetime associate of the National Academy of Sciences. Dr. Lupton has mentored more than 50 MS and Ph.D. students while at Texas A&M, and received the Dannon/American Society for Nutrition mentoring award in 2004. In 2007 she received the Texas A&M University distinguished achievement award for research. Dr. Lupton is immediate Past President of the American Society for Nutrition (ASN), the nutrition research organization. She is on the nutrition advisory committee to the Texas Commissioner for Agriculture. Dr. Lupton’s research is on the effect of diet on colon physiology and colon cancer with a particular focus on dietary fiber and n-3 fatty acids. Her research is supported by grants from the NIH/NCI, NASA, and NSBRI. Her undergraduate degree is from Mt. Holyoke College and her Ph.D. in Nutrition is from the University of California at Davis.
Joanne R. Lupton, Ph.D.
Distinguished Professor, University Faculty Fellow
William W. Allen Endowed Chair in Nutrition
Texas A&M University
ABSTRACT:
Notes from the crypt: What statistics can tell us about colon cancer
Our laboratory had shown that a combination of fish oil (high in omega 3 fatty acids) and pectin (a fiber easily fermented to butyrate) was protective of chemically-induced colon cancer through an up regulation of apoptosis (removal of cells) from the colonic crypt rather than through a decrease in colonocyte proliferation. In the post-Carroll era we learned considerably more about how and when that apoptotic response was initiated and propagated. In an early paper we assessed the relationship between DNA adduct levels, DNA repair enzyme expression and apoptosis throughout the time course of the study, which revealed that apoptosis as a means of DNA-damaged cell removal declines at the time when repair enzyme level starts to increase (1). Subsequently we showed that dietary fish oil reduces DNA adduct levels in rat colon in part by increasing apoptosis during tumor initiation. In fact, as DNA adduct level increased, the fish oil fed rats responded by increasing targeted apoptotic removal of DNA damaged cells, whereas the corn oil fed rats had the opposite response (2). Events analyzed by site specificity provided important information. We found that the lower tumor incidence in the distal colon as compared to the proximal colon may be a result of the capacity to deal with initial DNA damage by the distal colon, as compared with the proximal colon (3,4) which led us to further analysis of site-specific mechanisms in tumor development. This is important because distinct strategies may be required to protect against cancer at different sites. The site specific work has now led to documenting changes in gene expression profiles from mRNA in colon crypts from the colonic mucosa, and in evaluating patterns of colon cell gene expression over time using mRNA from exfoliated cells obtained noninvasively. In each part of this discovery process our thought process and analyses have been significantly enhanced by the creative and insightful collaboration of Raymond J. Carroll.
1. Hong MY, Chapkin RS, Wild CP, Morris JS, Wang N, Carroll RJ, Turner ND and Lupton JR. Relationship between DNA adduct levels, repair enzyme and apoptosis as a function of DNA methylation by azoxymethane. Cell Growth Differ. 10:749-758, 1999.
2. Hong MY, Lupton JR, Morris JS, Wang N, Carroll RJ, Davidson LA, Elder RH and Chapkin RS. Dietary fish oil reduces O6 methylguanine DNA adduct levels in rat colon in part by increasing apoptosis during tumor initiation. Cancer Epidemiol. Biomarkers Prev. 9:819-826, 2000.
3. Hong MY, Chapkin RS, Morris JS, Wang N, Carroll RJ, Turner ND, Chang WC, Davidson LA and Lupton JR. Anatomical site-specific response to DNA damage is related to later tumor development in the rat AOM colon carcinogenesis model. Carcinogenesis 22: 1831-1835, 2001.
4. Morris JS, Wang N, Lupton JR, Chapkin RS, Turner ND, Hong MY and Carroll RJ. Parametric and nonparametric methods for understanding the relationship between carcinogen-induced DNA adduct levels in distal and proximal regions of the colon. JASA 96:816-826, 2001.