title: Icaritin induces lytic cytotoxicity in extranodal NK/T-cell lymphoma.
abstract: BACKGROUND
  Extranodal NK/T-cell lymphoma (ENKL) is an aggressive hematological malignancy associated with Epstein-Barr virus (EBV) infection. It is often resistant to conventional chemotherapy and has a poor prognosis. Icaritin, a compound derived from Chinese herbal medicine, Herba Epimedii, has been reported to exert antitumor effects on a variety of cancer cell lines. In the present study, we investigated the cytotoxic effects of Icaritin on the two EBV-positive ENKL cell lines SNK-10 and SNT-8, along with the underlying molecular mechanisms.
  
  
  METHODS
  ENKL cell lines SNK-10 and SNT-8 were exposed to different concentrations of Icaritin for the indicated time. Treated cells were analyzed for cell proliferation, cell cycle, and cell apoptosis. Phosphorylation of Stat3 and Akt proteins in signaling pathways and the EBV-encoded LMP1 proteins were measured by Western blot. Expression of EBV genes was assessed by Real-Time PCR.
  
  
  RESULTS
  Our results showed that Icaritin dose-dependently inhibits ENKL cell proliferation and induces apoptosis and cell cycle arrest at G2/M phase. Additionally, Icaritin upregulates Bax, downregulates Bcl-2 and pBad, and activates caspase-3 and caspase-9. The anti-proliferative and pro-apoptotic effects of Icaritin are likely mediated by inhibition of Stat3 and Akt pathways through LMP1 downregulation. Importantly, Icaritin induces EBV lytic gene expression in ENKL cells, and the combination of Icaritin and the antiviral drug ganciclovir (GCV) is more effective in inducing ENKL cells apoptosis than Icaritin or GCV alone.
  
  
  CONCLUSIONS
  These findings indicate that EBV-targeted approaches may have significant therapeutic potential for ENKL treatment.
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, 12 Urumqi Middle Road, 200040, Shanghai, China. wuting2011@163.com.
authors.forename: Ting
authors.initials: T
authors.lastname: Wu
authors.affiliation: Laboratory of Molecular Biology, Training Center of Medical Experiments, School of Basic Medical Sciences, Fudan University, Shanghai, China. smwang2@fudan.edu.cn.
authors.forename: Songmei
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Integrative Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China. wujinfeng21@163.com.
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, 12 Urumqi Middle Road, 200040, Shanghai, China. zhiguang_lin@163.com.
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Department of Physiology & Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China. suixianxian@163.com.
authors.forename: Xianxian
authors.initials: X
authors.lastname: Sui
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, 12 Urumqi Middle Road, 200040, Shanghai, China. xpxu1111@163.com.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Virology, Division of Virology and Immunology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan. nshivir@mri.tmd.ac.jp.
authors.forename: Norio
authors.initials: N
authors.lastname: Shimizu
authors.affiliation: Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, 12 Urumqi Middle Road, 200040, Shanghai, China. bbchen@fudan.edu.cn.
authors.forename: Bobin
authors.initials: B
authors.lastname: Chen
authors.affiliation: Key Laboratory Medical Molecular Virology, MoE/MoH, and the Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, 131 Dongan Road, 200032, Shanghai, China. xywang@shmu.edu.cn.
authors.forename: Xuanyi
authors.initials: X
authors.lastname: Wang
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000633:toxicity*; D005419:Flavonoids / Q000633:toxicity*; D015774:Ganciclovir / Q000494:pharmacology; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D006801:Humans; D054391:Lymphoma, Extranodal NK-T-Cell / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism; D014763:Viral Matrix Proteins / Q000235:genetics
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D005419:Flavonoids; D050796:STAT3 Transcription Factor; D014763:Viral Matrix Proteins; D051057:Proto-Oncogene Proteins c-akt; D020169:Caspases; D015774:Ganciclovir; C499403:icaritin