Functional interrelationship between the WASF3 and KISS1 metastasis‐associated genes in breast cancer cells

Abstract

Loss of WASF3 function in breast cancer cells results in loss of invasion phenotypes and reduced metastatic potential. By using oligonucleotide arrays, we now demonstrate that knockdown of WASF3 leads to the upregulation of the KISS1 metastasis suppressor gene with concomitant reduced invasion and loss of matrix metalloproteinases (MMP)-9 activity. Using a luciferase reporter, KISS1 transcription is significantly increased in the absence of WASF3. Knockdown of KISS1 in WASF3-silenced cells resulted in the recovery of the invasion phenotype. WASF3 knockdown also resulted in elevated IjBa levels in the cytoplasm and reduced levels of nuclear factor-kappa-B (NF-jB) p65/50 subunits in the nucleus. Tumor necrosis factoralpha (TNF-a) has been associated with cell invasion through induction of MMP-9 production via KISS1 regulation of the NFjB pathway. When WASF3 knockdown cells are treated with TNF-a, no effect is seen on invasion or nuclear translocation of NF-jB. Thus, coordinated expression patterns of the WASF3 metastasis promoter gene and the KISS1 metastasis suppressor gene appear to exert their influence through inhibition of NF-jB signaling, which in turn regulates MMP-9 production facilitating invasion.The Wiskott-Aldrich syndrome protein (WASP) was the founding member of a family of proteins that now includes N-WASP and three members of the Wiskott-Aldrich syndrome protein family (WASF)/WASP family Verprolinhomologous protein (WAVE) family.1 This family of proteins is defined by a highly conserved group of motifs at their C-terminal ends; a WASP-homology-2 domain (WHD/V), a cofilin-homology domain (C) and an acidic domain (A). This verprolin central acidic (VCA) domain facilitates actin polymerization through binding monomeric actin and the ARP2/3 complex. Recently, we showed that inactivation of the WASF3/ WAVE3 gene in breast cancer cells results in loss of cell motility and invasion in vitro 2 and metastasis in vivo.3 The loss of cell motility is accompanied by a reduction in lamellipodia formation, even in the presence of normal expression levels of the WAVE1/2 proteins. Thus, the metastasis-promoting function of the WASF3 gene plays a critical and distinct role in coordinating actin dynamics related to cell motility, invasion and metastasis independently of the other WASF family members.2,3 The WASF proteins are normally maintained in an inactivated state in resting cells through the binding of a protein complex including PIR121, HSPC300, Abi1 and Nap125 to the WHD.1 On stimulation with growth factors such as platelet-derived growth factor (PDGF), the WASF complex breaks down allowing binding and activation of the Arp2/3 complex of proteins, resulting in actin polymerization. [4][5][6] Consistent with its role in promoting metastasis, WASF3 levels are elevated in advanced stage cancers compared to lower grade tumors and normal tissue, and knockdown of WASF3 in breast 7 and prostate cancer 8 cells results in decreased expression and activity of matrix metalloproteinases (MMP). These observations suggest a...

WAVE3 promotes epithelial–mesenchymal transition of gastric cancer through upregulation of Snail

“…18,19 The proteins of this family regulate actin polymerization through the recruitment of the Arp2/3 protein complex via a verprolin-cofilin-acidic domain at the C terminus. 20,21 Although, WAVE3 was frequently overexpressed in many human cancers, their expression in gastric cancer is seldom studied.…”

HSP90 and HSP70 Proteins Are Essential for Stabilization and Activation of WASF3 Metastasis-promoting Protein

“…In our recent gene expression studies, we demonstrated that knockdown of WASF3 led to significant changes in gene expression profiles (5). One significant change involved the upregulation of the KISS1 metastasis suppressor gene and downregulation of matrix metalloproteinase 9.…”

“…HSP90 has emerged as a promising target for the treatment of cancer and inhibition of its function by the 17-AAG drug leads to decreased cancer cell motility and invasion (15)(16)(17). We have recently demonstrated that WASF3 is important in controlling cell motility and invasion in breast and prostate cancer cells (2,3,5). To determine whether the interaction between WASF3 and HSP90 maintains protein stability, we inactivated HSP90 function using 17-AAG, which binds directly to the essential ATP/ADP binding pocket in the N-terminal region of HSP90 (8,18).…”

“…This function of WASF3 is regulated through its phosphorylation by ABL kinase (4). In primary breast (4,5) and prostate (3) cancer, WASF3 has been shown to be up-regulated in advanced stage tumors supporting a role in promoting metastasis. WASF3 has been shown to be in a complex with the p85 component of PI3K as well as ABL kinase (2), and other members of the WASF family also form a complex with at least four other proteins: Abi1/2, the Rac effector protein CYFIP1/2 (also known as PIR121), NCKAP1 (NAP1), and HSPC300 (6,7), which appear to hold the protein in an inactive form.…”

Surfing the big WAVE: Insights into the role of WAVE3 as a driving force in cancer progression and metastasis

“…Activation of MAPK pathways results in alterations in the expression levels and activity of MMPs, which in turn, are responsible for the degradation of extracellular matrix, and as such, are required for cell migration [87]. A recent study has also confirmed the important role of WAVE3 in the expression and activity of MMPs [88]. …”