Journal Article

NF-κB targets miR-16 and miR-21 in gastric cancer: involvement of prostaglandin E receptors

Vivian Y. Shin, Hongchuan Jin, Enders K.O. Ng, Alfred S.L. Cheng, Wilson W.S. Chong, Christine Y.P. Wong, Wai K. Leung, Joseph J.Y. Sung and Kent-Man Chu

in Carcinogenesis

Volume 32, issue 2, pages 240-245
Published in print February 2011 | ISSN: 0143-3334
Published online November 2010 | e-ISSN: 1460-2180 | DOI: http://dx.doi.org/10.1093/carcin/bgq240
NF-κB targets miR-16 and miR-21 in gastric cancer: involvement of prostaglandin E receptors

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Cigarette smoke is one of the risk factors for gastric cancer and nicotine has been reported to promote tumor growth. Deregulation of microRNA (miRNA) and cyclooxygenase-2 (COX-2) expressions are hallmarks of many cancers including gastric cancer. Here, we used an miRNA array platform covering a panel of 95 human miRNAs to examine the expression profile in nicotine-treated gastric cancer cells. We found that miR-16 and miR-21 were upregulated upon nicotine stimulation, transfection with anti-miR-16 or anti-miR-21 significantly abrogated cell proliferation. In contrast, ectopic miR-16 or miR-21 expression exhibited a similar stimulatory effect on cell proliferation as nicotine. Nicotine-mediated IkappaBα degradation and nuclear factor-kappa B (NF-κB) translocation dose-dependently. Knockdown of NF-κB by short interfering RNA (siRNA) or specific inhibitor (Bay-11-7085) markedly suppressed nicotine-induced cell proliferation and upregulation of miR-16 and miR-21. Interestingly, NF-κB-binding sites were located in both miR-16 and miR-21 gene transcriptional elements and we showed that nicotine enhanced the binding of NF-κB to the promoters of miR-16 and miR-21. Furthermore, activation of COX-2/prostaglandin E2 (PGE2) signaling in response to nicotine was mediated by the action of prostaglandin E receptors (EP2 and EP4). EP2 or EP4 siRNA or antagonists impaired the nicotine-mediated NF-κB activity, upregulation of miR-16 and miR-21 and cell proliferation. Taken together, these results suggest that miR-16 and miR-21 are directly regulated by the transcription factor NF-κB and yet nicotine-promoted cell proliferation is mediated via EP2/4 receptors. Perhaps this study may shed light on the development of anticancer drugs to improve the chemosensitivity in smokers.

Journal Article.  4114 words.  Illustrated.

Subjects: Clinical Cytogenetics and Molecular Genetics

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