title: Overexpression of HER2 signaling to WAVE2-Arp2/3 complex activates MMP-independent migration in breast cancer.
abstract: The final signal for triggering the formation of lamellipodia that initiate directional migration of mammalian cells is binding of the Wiskott-Aldrich syndrome (WASP)/WASP family verproline-homologous protein 2 (WAVE2) to the actin-related protein 2 and 3 (Arp2/3) complex. This WAVE2-Arp2/3 signal is suggested to be enhanced in some breast cancers, facilitating invasion, and/or metastasis. Here, we demonstrated one cause of the enhanced signal using four breast cancer cell lines (SKBR3, AU565, MCF7, and MDA-MB-231). The WAVE2-Arp2/3 signal was estimated semi-quantitatively by counting the number of lamellipodia expressing both WAVE2 and Arp2 using high-power confocal laser microscopy. Higher expression of the WAVE2-Arp2/3 signal was detected in SKBR3 and AU565, which have HER2 gene amplification, than in the other two cell lines that lack HER2 gene amplification. Trastuzumab suppressed both the formation of lamellipodia and migration in a Boyden chamber experiment in SKBR3 and AU565. When the HER2 gene was transfected into MCF7, the number of both lamellipodia and migrated cells was increased. This enhancement of migration did not occur in the presence of extracellular matrix, and zymographic analysis showed no clear difference between HER2 gene-transfected cells and MCF7 cells. Immunohistochemical analysis of 115 cases of breast cancer revealed that coexpression of WAVE2 and Arp2 was significantly correlated with HER2-overexpression (P < 0.0001). These data indicate that an abnormal signal resulting from HER2 gene amplification activates lamellipodia formation in breast cancer cells, which initiates their metalloproteinase-independent migration.
authors.affiliation: Department of Diagnostic Pathology, Tokyo Medical University, Shinjuku-ku, Tokyo, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Yokotsuka
authors.forename: Keiichi
authors.initials: K
authors.lastname: Iwaya
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Saito
authors.forename: Atanasio
authors.initials: A
authors.lastname: Pandiella
authors.forename: Ryoji
authors.initials: R
authors.lastname: Tsuboi
authors.forename: Norio
authors.initials: N
authors.lastname: Kohno
authors.forename: Osamu
authors.initials: O
authors.lastname: Matsubara
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Mukai
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D066246:ErbB Receptors / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D020880:Neuregulins / Q000494:pharmacology; D010766:Phosphorylation; D011554:Pseudopodia / Q000187:drug effects / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis*; D011994:Recombinant Proteins / Q000096:biosynthesis*; D015398:Signal Transduction; D000068878:Trastuzumab; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000378:metabolism*
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D066246:ErbB Receptors; D020778:Matrix Metalloproteinase 2; D020880:Neuregulins; D018719:Erb-b2 Receptor Tyrosine Kinases; D011994:Recombinant Proteins; D000068878:Trastuzumab; D051300:Wiskott-Aldrich Syndrome Protein Family; C120152:WASF2 protein, human; C508053:ERBB2 protein, human