Curcumin decreases cholangiocarcinogenesis in hamsters by suppressing inflammation-mediated molecular events related to multistep carcinogenesis Suksanti Prakobwong 1,2,3 , Jarinya Khoontawad 1,2 , Puangrat Yongvanit 2,4 , Chawalit Pairojkul 2,5 , Yusuke Hiraku 6 , Paiboon Sithithaworn 1,2 , Porntip Pinlaor 2,7 , Bharat B. Aggarwal 3 and Somchai Pinlaor 1,2 1 Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand 2 Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand 3 Department of Experimental Therapeutics, The University of Texas, M.D. Anderson Cancer Center, Houston, TX 4 Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand 5 Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand 6 Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Tsu, Mie, Japan 7 Centre for Research and Development in Medical Diagnostic Laboratory, Faculty of Associated Medical Science, Khon Kaen University, Khon Kaen, Thailand Cholangiocarcinoma (CCA) is a highly metastatic tumor linked to liver fluke infection and consumption of nitrosamine- contaminated foods and is a major health problem especially in South-Eastern Asia. In search for a suitable chemopreventive agents, we investigated the effect of curcumin, a traditional anti-inflammatory agent derived from turmeric (Curcuma longa), on CCA development in an animal model by infection with the liver fluke Opisthorchis viverrini and administration of N- nitrosodimethylamine and fed with curcumin-supplemented diet. The effect of curcumin-supplemented diet on histopathological changes and survival were assessed in relation to NF-jB activation, and the expression of NF-jB-related gene products involved in inflammation, DNA damage, apoptosis, cell proliferation, angiogenesis and metastasis. Our results showed that dietary administration of this nutraceutical significantly reduced the incidence of CCA and increased the survival of animals. This correlated with the suppression of the activation of transcription factors including NF-jB, AP-1 and STAT-3, and reduction in the expression of proinflammatory proteins such as COX-2 and iNOS. The formation of iNOS-dependent DNA lesions (8-nitroguanine and 8-oxo-7,8-dihydro-2 0 -deoxyguanosine) was inhibited. Curcumin suppressed the expression of proteins related to cell survival (bcl-2 and bcl-xL), proliferation (cyclin D1 and c-myc), tumor invasion (MMP-9 and ICAM-1) and angiogenesis (VEGF), and microvessel density. Induction of apoptotic events as indicated by caspase activation and PARP cleavage was also noted. Our results suggest that curcumin exhibits an anticarcinogenic potential via suppression of various events involved in multiple steps of carcinogenesis, which is accounted for by its ability to suppress proinflammatory pathways. Cholangiocarcinoma (CCA) is a bile duct cancer with high incidence rate in northeastern Thailand where liver fluke Opisthorchis viverrini is endemic. 1,2 The incidence rate of CCA is highest in Khon Kaen province with age standardized rate of 89.2/100,000 in males and 37.4/100,000 in females 3 with range from 93.8 to 317.6/100,000 person-years. 4 The risk factors for CCA in Thailand include not only parasite infection but also exposure to the carcinogen nitrosamine Key words: Opisthorchis viverrini, cholangiocarcinoma, curcumin, DNA damage, apoptosis, cell proliferation, angiogenesis Abbreviations: AP-1, activating protein-1; Bcl-2, B-cell lymphoma protein-2; Bcl-xL, B-cell leukemia-xL; COX-2, cyclooxygenase 2; EMSA, electrophoretic mobility shift assay; ICAM-1, intracellular adhesion molecule-1; iNOS, inducible nitric oxide synthase; JAK, janus kinase; MMP-9, matrix metalloproteinase-9; NF-jB, nuclear factor-kappaB; STAT-3, signal transducer and activator of transcription 3; TRAF, tumor necrosis factor receptor-associated factor; VEGF, vascular endothelial growth factor Grant sponsors: Research Team Strengthening Grant, National Center for Genetic engineering and Biotechnology, National Science and Technology Development Agency, Thailand, Khon Kaen University Research Foundation, Thailand DOI: 10.1002/ijc.25656 History: Received 13 Jun 2010; Accepted 23 Aug 2010; Online 7 Sep 2010 Correspondence to: Somchai Pinlaor, Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand, Tel.: þ66-43-348-387, Fax: þ66-43-202-475, E-mail: psomec@kku.ac.th; or Bharat B. Aggarwal, Department of Experimental Therapeutics, The University of Texas, M.D. Anderson Cancer Center, Houston, Texas 77030, Tel.: 713-794-1817, Fax: 713-794-1613, E-mail: aggarwal@ mdanderson.org Infectious Causes of Cancer Int. J. Cancer: 129, 88–100 (2011) V C 2010 UICC International Journal of Cancer IJC