Tea Polyphenols Induce Apoptosis Through Mitochondrial Pathway and by Inhibiting Nuclear Factor-κB and Akt Activation in Human Cervical Cancer Cells
Abstract:Phytochemicals present in tea, particularly polyphenols, have anticancer properties against several cancer types. However, studies elucidating the role and the mechanism(s) of action of tea polyphenols in cervical cancer are sparse. In this study, we investigated the mechanism of antiproliferative and apoptotic actions exerted by tea polyphenols on human papilloma virus-18-positive HeLa cervical cancer cells. Treatment of green tea polyphenol (−)-epigallocatechin gallate (EGCG) and black tea polyphenol theaflavins (TF) in HeLa cells showed a marked concentration- and time-dependent inhibition of proliferation and induced sub-G1 phase in a dose-dependent manner after 24 h. There was an attenuation of mitochondrial membrane potential with the increase of reactive oxygen species generation, p53 expression, Bax/Bcl-2 ratio, cytochrome-c release, and cleavage of procaspase-3 and -9 and poly(ADP-ribose)-polymerase, indicating the participation of a mitochondria related mechanism. In addition, EGCG as well as TF inhibited activation of Akt and nuclear factor-κB (NF-κB) via blocking phosphorylation and subsequent degradation of inhibitor of κBα and κBβ subunits, thereby downregulating cyclooxygenase-2. Additionally, the protein level of cyclin D1, a transcriptional target of NF-κB, was also reduced significantly. Thus, we can conclude that tea polyphenols inhibit the growth of cervical cancer cells by inducing apoptosis and regulating NF-κB and Akt.
Document Type: Research Article
Publication date: June 1, 2011
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- Formerly: Oncology Research Incorporating Anti-Cancer Drug Design
Oncology Research Featuring Preclinical and Clincal Cancer Therapeutics publishes research of the highest quality that contributes to an understanding of cancer in areas of molecular biology, cell biology, biochemistry, biophysics, genetics, biology, endocrinology, and immunology, as well as studies on the mechanism of action of carcinogens and therapeutic agents, reports dealing with cancer prevention and epidemiology, and clinical trials delineating effective new therapeutic regimens.