Mj. Weyant et al., (+)-Catechin inhibits intestinal tumor formation and suppresses focal adhesion kinase activation in the Min/+ mouse, CANCER RES, 61(1), 2001, pp. 118-125
Colorectal cancer is sensitive to dietary influences. Epidemiological data
linking high intake of fruits and vegetables to decreased cancer risk have
prompted the search for specific plant constituents implicated in tumor pre
vention. This task is difficult because of the complex chemical composition
of plant foods and the multifactorial nature of carcinogenesis. Researcher
s are aided in this effort by the C57BL/6J-Min/+ (Min/+) mouse, an animal h
earing a germline defect in Apc that is similar to the initiating genetic e
vent in the majority of human colorectal cancers. In this study, we treated
Min/+ mice with (+)-catechin, a phenolic antioxidant abundant in certain f
ruits. Administration of (+)-catechin in an AIN-76A diet at doses of 0.1 an
d 1% decreased the intestinal tumor number by 75 and 71%, respectively. Mec
hanistic studies linked this effect to (+)-catechin-induced changes in inte
grin-mediated intestinal cell-survival signaling, including structural alte
ration of the actin cytoskeleton and decreased focal adhesion kinase (FAK)
tyrosine phosphorylation. Immunoblot analysis of small intestine scrapings
from Min/+ mice and Apc(+/+) wild-type C57BL/6J littermates together with e
xcised Min/+ adenomas showed increased expression of phosphorylated FAK in
the macroscopically normal enterocytes of untreated Min/+ mice and adenomas
. Confirming the relevance of this signaling pathway, treatment of Min/+ mi
ce with (+)-catechin reduced the expression of phosphorylated FAK to a leve
l similar to the wild-type littermate controls. Thus, the natural abundance
and favorable bioavailability of (+)-catechin make it a promising addition
to the list of potential colorectal cancer chemopreventive agents.