SNARE-dependent interaction of Src, EGFR and β1 integrin regulates invadopodia formation and tumor cell invasion

Abstract

Acquisition of an invasive phenotype is prerequisite for tumor metastasis. Degradation of the extracellular matrix (ECM), and subsequent invasion by tumor cells, is mediated, in part, through subcellular structures called invadopodia. Src-dependent cytoskeletal rearrangements are required to form invadopodia, and here we identify an association between Src, epidermal growth factor receptor (EGFR), and b1 integrin that facilitates invadopodia formation. The association of Src, EGFR and b1 integrin is dependent upon membrane traffic that is mediated by syntaxin13 (officially known as STX12) and SNAP23; a similar dependence on these two SNARE proteins was observed for invadopodium-based matrix degradation and cell invasion. Inhibition of SNARE function impaired the delivery of Src and EGFR to developing invadopodia, as well as the b1-integrin-dependent activation of Src and phosphorylation of EGFR on Tyr residue 845. We also identified an association between SNAP23 and b1 integrin, and inhibition of b1 integrin increased this association, whereas the interaction between syntaxin13 and SNAP23 was reduced. The results suggest that SNARE-dependent trafficking is regulated, in part, by b1 integrin and is required for the delivery of Src and EGFR to sites of invadopodia formation in order to support tumor cell invasion.

The cross-talk of LDL-cholesterol with cell motility: Insights from the Niemann Pick Type C1 mutation and altered integrin trafficking

“…Thus, other Stx4/SNAP23-dependent migration events, including a5 integrin, Src and FAK trafficking and activation at focal adhesions, and MT1-MMP delivery to invadopodia in MDA-MB-231 breast cancer cells, may also be affected by LDLcholesterol egress from LE. 28,29 Further insight comes from Stx6, which participates in LE-cholesterol delivery to the ER, and regulates lipid and protein transport, including caveolin, required for caveolae endocytosis. 30 In HeLa and other cancer cell models, Stx6 depletion reduces caveolae numbers, impedes a3b1 and a5b1 integrin recycling and delivery of FAK to focal adhesions.…”

“…34,35 Besides Stx4/ SNAP23, Stx6 and VAMP3 (see above), VAMP2 also participates in transport and recycling of a5, a3, b1 integrin and FAK, 26 while Stx12 together with SNAP23 is required for Src and b1 integrin transport to cholesterol-rich invadopodia for cell invasion. 29 These regulatory circuits seem to exist in various cancer cell lines, and it is tempting to speculate that all these SNAREs in a large number of cells may respond to temporal and local changes in LDL-or HDL-cholesterol delivery. The molecular basis enabling cholesterol to control integrin trafficking via SNAREs remains to be determined.…”

Regulation of invadopodia by mechanical signaling

“…Multiple adhesion and contractility molecules localize to and around invadopodia, suggesting that some of the ECM rigidity response may occur directly at invadopodia [26, 62, 67, 70, 79]. While CD44 and β3 integrins have been found at invadopodia [80, 81], β1 integrins appear to be the predominant adhesion molecules found at or around their actin cores [49, 79, 82-85]. Although this localization could be due to the predominant use of fibronectin matrix for in vitro invadopodia assays, β1 integrins are frequently associated with cancer progression [49, 79, 82-85].…”

“…While CD44 and β3 integrins have been found at invadopodia [80, 81], β1 integrins appear to be the predominant adhesion molecules found at or around their actin cores [49, 79, 82-85]. Although this localization could be due to the predominant use of fibronectin matrix for in vitro invadopodia assays, β1 integrins are frequently associated with cancer progression [49, 79, 82-85]. β1 integrins have been found to regulate invadopodia by forming signaling complexes with Src, EGFR, and/or FAK [82, 85].…”

“…Although this localization could be due to the predominant use of fibronectin matrix for in vitro invadopodia assays, β1 integrins are frequently associated with cancer progression [49, 79, 82-85]. β1 integrins have been found to regulate invadopodia by forming signaling complexes with Src, EGFR, and/or FAK [82, 85]. In addition, β1 integrins have been shown to promote invadopodia maturation to actively degrading structures by mechanisms that include signal complex formation with ezrin at lipid rafts, regulation of actin dynamics by Arg, docking of the gelatinolytic enzyme seprase, and promotion of MMP secretion via integrin-linked kinase-IQGAP interactions (Fig.…”