title: Antioxidant dieckol downregulates the Rac1/ROS signaling pathway and inhibits Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein 2 (WAVE2)-mediated invasive migration of B16 mouse melanoma cells.
abstract: Reactive oxygen species (ROS) generation is linked to dynamic actin cytoskeleton reorganization, which is involved in tumor cell motility and metastasis. Thus, inhibition of ROS generation and actin polymerization in tumor cells may represent an effective anticancer strategy. However, the molecular basis of this signaling pathway is currently unknown. Here, we show that the Ecklonia cava-derived antioxidant dieckol downregulates the Rac1/ROS signaling pathway and inhibits Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein 2 (WAVE2)-mediated invasive migration of B16 mouse melanoma cells. Steady-state intracellular ROS levels were higher in malignant B16F10 cells than in parental, nonmetastatic B16F0 cells. Elevation of ROS by H(2)O(2) treatment increased migration and invasion ability of B16F0 cells to level similar to that of B16F10 cells, suggesting that intracellular ROS signaling mediates the prometastatic properties of B16 mouse melanoma cells. ROS levels and the cell migration and invasion ability of B16 melanoma cells correlated with Rac1 activation and WAVE2 expression. Overexpression of dominant negative Rac1 and depletion of WAVE2 by siRNA suppressed H(2)O(2)-induced cell invasion of B16F0 and B16F10 cells. Similarly, dieckol attenuates the ROS-mediated Rac1 activation and WAVE2 expression, resulting in decreased migration and invasion of B16 melanoma cells. In addition, we found that dieckol decreases association between WAVE2 and NADPH oxidase subunit p47(phox). Therefore, this finding suggests that WAVE2 acts to couple intracellular Rac1/ROS signaling to the invasive migration of B16 melanoma cells, which is inhibited by dieckol.
authors.affiliation: Department of Chemistry, Pukyong National University, Busan 608-737, Korea. parksj@pknu.ac.kr
authors.forename: Sun Joo
authors.initials: SJ
authors.lastname: Park
authors.forename: Yong Tae
authors.initials: YT
authors.lastname: Kim
authors.forename: You Jin
authors.initials: YJ
authors.lastname: Jeon
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects; D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology; D001572:Benzofurans / Q000737:chemistry / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects* / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008546:Melanoma, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051379:Mice; D009361:Neoplasm Invasiveness / Q000235:genetics; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D000459:Phaeophyceae / Q000737:chemistry; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000235:genetics / Q000378:metabolism*; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein
chemical_list: D000975:Antioxidants; D001572:Benzofurans; D009479:Neuropeptides; D034741:RNA, Small Interfering; C484602:Rac1 protein, mouse; D017382:Reactive Oxygen Species; C492303:Wasf2 protein, mouse; D051300:Wiskott-Aldrich Syndrome Protein Family; C503840:dieckol; D006861:Hydrogen Peroxide; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein