title: Fucoidan-induced ID-1 suppression inhibits the in vitro and in vivo invasion of hepatocellular carcinoma cells.
abstract: Hepatocellular carcinoma (HCC) is a fast growing tumor associated with a high tendency for vascular invasion and distant metastasis. Recently, we reported that fucoidan displays inhibitory effect on proliferation and invasion of HCC cells. In this study, we investigated the anti-metastatic effect of fucoidan on HCC cells and the key signal that modulates metastasis. The anti-metastatic effect of fucoidan was evaluated in vitro using an invasion assay with human HCC cells (Huh-7, SNU-761, and SNU-3085) under both normoxic (20% O2and 5% CO2, at 37°C) and hypoxic (1% O2,5% CO2, and 94% N2,at 37°C) conditions. Complementary DNA (cDNA) microarray analysis was performed to find the molecule which is significantly suppressed by fucoidan. In vivo study using a distant metastasis model by injecting SNU-761 cells into spleen via portal vein was performed to confirm the inhibitory effect by small interfering RNA (siRNA) transfection. Immunoblot analyses were used to investigate the signaling pathway. Fucoidan significantly suppressed the invasion of human HCC cells (Huh-7, SNU-761, and SNU-3085). Using cDNA microarray analysis, we found the molecule, ID-1, which was significantly suppressed by fucoidan treatment. Downregulation of ID-1 by siRNA significantly decreased invasion of HCC cells, both in vitro and in vivo (both P<0.05) in a NDRG-1/CAP43-dependent manner. In immunoblot assay, downregulation of ID-1 by siRNA decreased the expressions of epithelial-mesenchymal transition markers including CK19, vimentin, MMP2, and fibronectin. Immunofluorescence study also revealed that actin rearrangement was inhibited when ID-1 was down-regulated in HCC cells. Interestingly, in SNU-761 cells, the ID-1 expressions under hypoxic conditions were lower as compared to those under normoxic conditions. Under hypoxic conditions, HIF-1α up-regulated NDRG-1/CAP43, while HIF-2α down-regulated ID-1, which might be a compensatory phenomenon against hypoxia-induced HCC invasion. In conclusion, NDRG-1/CAP43-dependent down-regulation of ID-1 suppressed HCC invasion both in vitro and in vivo, which was modulated by fucoidan treatment. Moreover, the compensatory down-regulation of ID-1 against hypoxia-induced HCC invasion was observed. ID-1 is a novel therapeutic target for the treatment of metastatic HCC.
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Internal Medicine, CHA Gangnam Medical Center, CHA University, Seoul, Republic of Korea.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Cho
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Cho
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jeong-Hoon
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Su Jong
authors.initials: SJ
authors.lastname: Yu
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Yoon Jun
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Chung Yong
authors.initials: CY
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: yoonjh@snu.ac.kr.
authors.forename: Jung-Hwan
authors.initials: JH
authors.lastname: Yoon
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology*; D015687:Cell Hypoxia / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D051798:Inhibitor of Differentiation Protein 1 / Q000235:genetics* / Q000378:metabolism; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology*; D008297:Male; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D011134:Polysaccharides / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D014162:Transfection; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D014408:Biomarkers, Tumor; D051798:Inhibitor of Differentiation Protein 1; D011134:Polysaccharides; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D000099162:Endothelial PAS Domain-Containing Protein 1; C497453:ID1 protein, human; C007789:fucoidan
keywords: Fucoidan; Hepatocellular carcinoma; Hypoxia; ID-1; Metastasis; NDRG/CAP43