Tea polyphenols inhibit cyclooxygenase-2 expression and block activation of nuclear factor-kappa B and Akt in diethylnitrosoamine induced lung tumors in Swiss mice
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Background Due to lack of validated screening methods and hence poor prognosis, treatment of lung cancer has not still improved up to the expectations. Therefore, risk of lung cancer needs to be minimized by efficient preventive measures. Tea (Camellia sinensis) and its bioactive polyphenols have been associated with prevention of human cancer for several organs. Thus, intake of tea polyphenols seems to be a viable mean to control lung cancer burden. In the present study, we studied the chemopreventive effects of green tea polyphenols (GTP) and black tea polyphenols (BTP) against diethylnitrosoamine (DEN) induced lung tumors in Swiss albino mice. Results Chemopreventive potential of tea polyphenols, was recorded as evident by, low incidence of alveologenic tumors in lungs of animals at tested doses (0.1% and 0.2% of both GTP and BTP) when compared with DEN (20 mg/kg b wt) treated animals. As a mechanism of cancer chemoprevention cellular signaling pathways were also targeted. GTP and BTP treatment inhibited the expression of Akt, cyclooxygenase-2 and inactivated nuclear factor-kappa B via blocking phosphorylation and subsequent degradation of IκBα. Conclusion Thus, the study suggests that polyphenolic constituents of both cultivars of tea, i.e. green and black, have chemopreventive effects in DEN induced lung tumorigenesis in Swiss albino mice.
KeywordsChemoprevention Tea polyphenols Lung tumor Cox-2 NF-ĸB Akt
Authors are thankful to Director, Indian Institute of Toxicology Research, Lucknow for his keen interest in the study. Authors are also thankful to Department of Biotechnology (India) and Council of Scientific and Industrial Research, New Delhi for funding this work from NWP-17. Thanks are also due to Indfrag chemical company, Bangalore, India for providing tea polyphenols. The computer aided support of Ms. Babita Singh is also gratefully acknowledged.
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