Rac-WAVE2 signaling is involved in the invasive and metastatic phenotypes of murine melanoma cells.
WAVEs (WASP-family verprolin-homologous proteins) regulate the actin cytoskeleton through activation of Arp2/3 complex. As cell motility is regulated by actin cytoskeleton rearrangement and is required for tumor invasion and metastasis, blocking actin polymerization may be an effective strategy to prevent tumor dissemination. We show that WAVEs, especially WAVE2, are essential for invasion and metastasis of melanoma cells. Malignant B16F10 mouse melanoma cells expressed more WAVE1 and WAVE2 proteins and showed higher Rac activity than B16 parental cells, which are neither invasive nor metastatic. The effect of WAVE2 silencing by RNA interference (RNAi) on the highly invasive nature of B16F10 cells was more dramatic than that of WAVE1 RNAi. Membrane ruffling, cell motility, invasion into the extracellular matrix, and pulmonary metastasis of B16F10 cells were suppressed by WAVE2 RNAi. WAVE2 RNAi also had a profound effect on invasion induced by a constitutively active form of Rac (RacCA). In addition, ectopic expression of both RacCA and WAVE2 in B16 cells resulted in further increase in the invasiveness than that observed in B16 cells expressing only RacCA. Thus, WAVE2 acts as the primary effector downstream of Rac to achieve invasion and metastasis, suggesting that suppression of WAVE2 activity holds a promise for preventing cancer invasion and metastasis.
Kurisu
Shusaku
S
Department of Biochemistry, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
Suetsugu
Shiro
S
Yamazaki
Daisuke
D
Yamaguchi
Hideki
H
Takenawa
Tadaomi
T
D000199:Actins / Q000032:analysis / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D003094:Collagen / Q000737:chemistry; D004338:Drug Combinations; D007797:Laminin / Q000737:chemistry; D008175:Lung Neoplasms / Q000556:secondary; D008546:Melanoma, Experimental / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008840:Microfilament Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis / Q000473:pathology; D010641:Phenotype; D011509:Proteoglycans / Q000737:chemistry; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction; D051300:Wiskott-Aldrich Syndrome Protein Family; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000502:physiology*
D000199:Actins; D004338:Drug Combinations; D007797:Laminin; D008840:Microfilament Proteins; D011509:Proteoglycans; D034741:RNA, Small Interfering; C495774:Wasf1 protein, mouse; C492303:Wasf2 protein, mouse; D051300:Wiskott-Aldrich Syndrome Protein Family; C059485:matrigel; D003094:Collagen; D020744:rac GTP-Binding Proteins