N-WASP and cortactin are involved in invadopodium-dependent chemotaxis to EGF in breast tumor cells.
Metastatic mammary carcinoma cells, which have previously been observed to form mature, matrix degrading invadopodia on a thick ECM matrix, are able to form invadopodia with similar characteristics on glass without previously applied matrix. They form in response to epidermal growth factor (EGF), and contain the usual invadopodium core proteins N-WASP, Arp2/3, cortactin, cofilin, and F-actin. The study of invadopodia on glass allows for higher resolution analysis including the use of total internal reflection microscopy and analysis of their relationship to other cell motility events, in particular, lamellipodium extension and chemotaxis toward an EGF gradient. Invadopodium formation on glass requires N-WASP and cortactin but not microtubules. In a gradient of EGF more invadopodia form on the side of the cells facing the source of EGF. In addition, depletion of N-WASP or cortactin, which blocks invadopodium fromation, inhibits chemotaxis of cells towards EGF. This appears to be a localized defect in chemotaxis since depletion of N-WASP or cortactin via siRNA had no effect on lamellipodium protrusion or barbed end generation at the lamellipodium's leading edge. Since chemotaxis to EGF by breast tumor cells is involved in metastasis, inhibiting N-WASP activity in breast tumor cells might prevent metastasis of tumor cells while not affecting chemotaxis-dependent innate immunity which depends on WASp function in macrophages.
Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA. vdesmara@aecom.yu.edu
Vera
V
Desmarais
Hideki
H
Yamaguchi
Matthew
M
Oser
Lilian
L
Soon
Ghassan
G
Mouneimne
Corina
C
Sarmiento
Robert
R
Eddy
John
J
Condeelis
D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D002633:Chemotaxis / Q000235:genetics; D051356:Cortactin / Q000235:genetics / Q000502:physiology*; D051345:Destrin / Q000235:genetics / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism*; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D011554:Pseudopodia / Q000187:drug effects / Q000502:physiology; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000235:genetics / Q000502:physiology*
D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D051356:Cortactin; D051345:Destrin; D034741:RNA, Small Interfering; C495770:Wasl protein, rat; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D004815:Epidermal Growth Factor