ORIGINAL ARTICLE Suppressive function of low-dose deguelin on the invasion of oral cancer cells by downregulating tumor necrosis factor alpha–induced nuclear factor-kappa B signaling Yu-Peng Liu, PhD, 1,2,4 Jih-Jong Lee, DVM, PhD, 3 Tsung-Ching Lai, MS, 4 Chien-Hsin Lee, PhD, 4 Ya-Wen Hsiao, DVM, PhD, 5 Po-Shen Chen, MS, 6 Wei-Ting Liu, PhD, 7 Chi-Yuan Hong, DDS, PhD, 8 Se-Kwan Lin, DDS, PhD, 8 Mark-Yen Ping Kuo, DDS, PhD, 8 Pei-Jung Lu, PhD, 9 Michael Hsiao, DVM, PhD 4 * 1 Department of Genome Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, 2 Center for Infectious Disease and Cancer Research, Kaohsiung Medical University, Kaoh- siung, Taiwan, 3 Department of Veterinary Medicine, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan, 4 Genomics Research Center, Academia Sinica, Taipei, Taiwan, 5 Department of Cardiology, Taipei Veterans General Hospital, Taipei, Taiwan, 6 Graduate School of Biomedical Sciences, University of Massachusetts Medi- cal School, Worcester, Massachusetts, 7 Institute of Pharmacology, National Cheng-Kung University, Tainan, Taiwan, 8 Institute of Clinical Dentistry, School of Dentistry, National Taiwan University Hospital, Taipei, Taiwan, 9 Institute of Clinical Medicine, National Cheng-Kung University, Tainan, Taiwan. Accepted 5 March 2015 Published online 15 July 2015 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/hed.24034 ABSTRACT: Background. Deguelin has both antiproliferation and anti- metastasis activities. However, high-dose deguelin elicits many unde- sired side effects. The purpose of this study was to investigate whether the low-dose deguelin can prevent the metastasis of oral cancer. Methods. The dose effects of deguelin on metastasis of oral cancer cells were analyzed by in vitro invasion assay and an orthotropic xenograft mouse model. The involvement of tumor necrosis factor alpha (TNF-a)- induced nuclear factor-kappa B (NF-jB) signaling was examined by Western blot and reporter assay. Results. Low-dose deguelin, which has minimal cytotoxicity, significantly inhibited the invasion and migration of oral cancer cells. These inhibitory effects of low-dose deguelin were mediated by suppressing TNF-a- induced activation of IjB kinase leading to the inhibition of IjB phospho- rylation, NF-jB transcriptional activity, and matrix metalloproteinase-2 (MMP2) expression. The low-dose deguelin treatment significantly inhib- ited tumor growth and invasion without systemic toxicity. Conclusion. The low-dose deguelin suppressed the invasion and migra- tion of oral cancer by downregulating TNF-a-induced NF-jB signaling. V C 2015 Wiley Periodicals, Inc. Head Neck 38: E524–E534, 2016 KEY WORDS: deguelin, oral cancer, invasion, nuclear factor-kappa B (NF-jB), matrix metalloproteinase-2 (MMP2) INTRODUCTION Oral cavity cancer or oral cancer, a subtype of head and neck cancer, is defined as any cancerous tissue growth located in the oral cavity. The most common subtype of oral cancer is oral squamous cell carcinoma (OSCC), originating in the tissue that lines the mouth and lips. In 2010, approximately 36,540 individuals were diagnosed with oral cancer in the United States, and there were 7880 deaths because of the disease. 1 Nearly 50% of patients with OSCC present pathologic or clinical evi- dence of lymph node metastasis and, as a result, the 5- year survival rate is <50%. 2 Death from oral cancer is often the result of local recurrence or regional metastasis. Thus, it is imperative to explore new agents for prevent- ing oral cancer invasion and metastasis. Deguelin (Figure 1A), a member of the rotenoid family, was isolated from Mundulea sericea, which is part of the Leguminosae family. It downregulates the expression or activation of several signaling effectors, such as heat shock protein 90, phosphatidylinositol 3-kinases/Akt, mitogen- activated protein kinase kinase-1/2, hypoxia-inducible fac- tor-1a, cyclooxygenase-2, and nuclear factor-kappa B (NF- jB) in various types of cancer cells. 3–7 Because of its apo- ptotic activity through the induction of cell cycle arrest in the G2/M phase, deguelin has been investigated as a poten- tial chemopreventive and chemotherapeutic agent for sev- eral cancer types. As a single agent, deguelin decreased cellular viability at higher doses (>1 mM), but inhibited the activities of some signaling molecules over a wide dos- ing range (0.1–10 mM). Unfortunately, treatment of deguelin at high dose exhibits undesirable side effects, such as respiratory depression and cardiotoxicity. 8 Recently, a number of studies showed that low dose of deguelin (<1 mM) preserved its antitumor activity in triple-negative breast cancer, 9 lung cancer, 10 colon can- cer, 11 and glioblastoma multiforme. 12 These findings indi- cate that the therapeutic index (the ratio of effectiveness and toxicity) of deguelin in different cancer types could be different, and the dose effect of deguelin in normal and cancer cells should be carefully evaluated. *Corresponding author: M. Hsiao, Genomics Research Center, Academia Sinica, 128 Academia Rd., Sec. 2 Nankang District, Taipei, Taiwan. E-mail: mhsiao@gate.sinica.edu.tw Yu-Peng Liu and Jih-Jong Lee contributed equally to this work. Additional Supporting Information may be found in the online version of this article. E524 HEAD & NECK—DOI 10.1002/HED APRIL 2016