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S12
Environment-gene interactions in intestinal cancer
Leonard H Augenlicht,
Barbara G Heerdt, John M Mariadason, WanCai Yang, Andrew
J Wilson, Alessandra Fragale, Anna Velcich
Only 5-10% of all
colorectal cancer in the United States can be directly
attributed to inheritance of genetic predisposition for
tumor development. Thus, the vast majority of colorectal
cancer is classified as sporadic, and in these patients
environmental factors – particularly the diet – play a
major role in determining the probability of tumor
formation and its progression. Investigations of how
dietary components interact with genetic factors in
cancer development have been extremely productive in
terms of understanding the subtle and complex mechanisms
that maintain homeostasis of the intestinal mucosa, and
how perturbations in these mechanisms cause disease. We
have found that the cyclin-dependent kinase inhibitor
p21WAF1/cip1 plays a major role in regulating
several aspects of mucosal homeostasis and the response
to dietary and pharmacologic modulators of tumorigenesis;
that disruption of lineages of differentiation of
intestinal epithelial cells are intimately involved in
tumor formation; and that important pathways that
contribute to normal homeostasis and cancer development
may be coordinately regulated by mitochondrial function,
with the mitochondrial membrane potential playing a key
role. Several lines of evidence from our work have also
suggested that intestinal epithelial cells have adapted
to the environment that they usually encounter. This
renders the cells competent to efficiently utilize
factors in the intestinal lumen in normal metabolic and
signaling pathways that contribute to homeostasis.
Key words: Colon
cancer, genomics, fatty acids, mitochondria, mucin,
differentiation.
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