|dc.description.abstract||The present study was carried out to examine the chemopreventive effects of
curcumin and green tea polyphenols on the hamster cheek pouch carcinogenesis model.
This model of oral carcinogenesis has been widely used in chemoprevention studies,
however, these studies have been limited to the use of DMBA as the carcinogenic
agent. We have developed a protocol of carcinogenesis in the hamster cheek pouch
using B[a]P, a broadly distributed environmental carcinogen, formed as a by-product of
the combustion of organic materials including cigarette smoke. B[a]P- induced tumors
in the hamster cheek pouch are primarily endophytic squamous cell carcinomas that
closely resemble squamous cell carcinomas of the human oral mucosa. The cheek
pouch of male Syrian hamsters were treated topically for eight weeks with 0.6%
curcumin, 6.0% curcumin, 2.5% green tea polyphenols, or 5.0% green tea polyphenols,
3 times per week 30 minutes prior to the application of 2.0% B[a]P.
The animals were sacrificed 24 hours and 72 hours after the last treatments.
Short-term mechanistic markers of malignant progression were used to determine
effects of each compound. Cellular proliferation, assessed by bromodeoxyuridine
(Brdu) incorporation, p53 protein accumulation, and apoptotic activity were evaluated.
The results of the present study demonstrated that 0.6% curcumin and 2.5% green tea
polyphenols had strong inhibitory effects on cellular proliferation and p53 protein
accumulation. And 6.0% curcumin and 5.0% green tea polyphenols appeared to induce
apoptosis. Our data suggest that curcumin and green tea polyphenols may have a
plausible chemopreventive effect on oral carcinogenesis in the hamster cheek pouch