VCA nanobodies target N-WASp to reduce invadopodium formation and functioning

PLoS One. 2017 Sep 22;12(9):e0185076. doi: 10.1371/journal.pone.0185076. eCollection 2017.

Abstract

Invasive cancer cells develop small actin-based protrusions called invadopodia, which perform a primordial role in metastasis and extracellular matrix remodelling. Neural Wiskott-Aldrich syndrome protein (N-WASp) is a scaffold protein which can directly bind to actin monomers and Arp2/3 and is a crucial player in the formation of an invadopodium precursor. Expression modulation has pointed to an important role for N-WASp in invadopodium formation but the role of its C-terminal VCA domain in this process remains unknown. In this study, we generated alpaca nanobodies against the N-WASp VCA domain and investigated if these nanobodies affect invadopodium formation. By using this approach, we were able to study functions of a selected functional/structural N-WASp protein domain in living cells, without requiring overexpression, dominant negative mutants or siRNAs which target the gene, and hence the entire protein. When expressed as intrabodies, the VCA nanobodies significantly reduced invadopodium formation in both MDA-MB-231 breast cancer and HNSCC61 head and neck squamous cancer cells. Furthermore, expression of distinct VCA Nbs (VCA Nb7 and VCA Nb14) in PC-3 prostate cancer cells resulted in reduced overall matrix degradation without affecting MMP9 secretion/activation or MT1-MMP localisation at invadopodial membranes. From these results, we conclude that we have generated nanobodies targeting N-WASp which reduce invadopodium formation and functioning, most likely via regulation of N-WASp-Arp2/3 complex interaction, indicating that this region of N-WASp plays an important role in these processes.

MeSH terms

  • Actin-Related Protein 2-3 Complex / metabolism
  • Actins / metabolism
  • Antibody Affinity
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Extracellular Matrix / metabolism
  • HEK293 Cells
  • Head and Neck Neoplasms / metabolism
  • Head and Neck Neoplasms / pathology
  • Humans
  • Intracellular Space / metabolism
  • Male
  • Mitochondrial Membranes / metabolism
  • Mitochondrial Membranes / pathology
  • Neoplasms / metabolism*
  • Neoplasms / pathology*
  • Neoplasms, Squamous Cell / metabolism
  • Neoplasms, Squamous Cell / pathology
  • Podosomes / metabolism*
  • Podosomes / pathology
  • Prostatic Neoplasms / metabolism
  • Prostatic Neoplasms / pathology
  • Protein Binding
  • Protein Domains
  • Single-Domain Antibodies / immunology
  • Single-Domain Antibodies / metabolism*
  • Wiskott-Aldrich Syndrome Protein, Neuronal / chemistry
  • Wiskott-Aldrich Syndrome Protein, Neuronal / immunology*
  • Wiskott-Aldrich Syndrome Protein, Neuronal / metabolism*

Substances

  • Actin-Related Protein 2-3 Complex
  • Actins
  • Single-Domain Antibodies
  • WASL protein, human
  • Wiskott-Aldrich Syndrome Protein, Neuronal

Grants and funding

This work was funded by Research Foundation Flanders, Ghent University (BOF13/GOA/010), Emmanuel van der Schueren, Flemish League against Cancer (VLK), and Agency for Innovation by Science and Technology in Flanders (IWT).