Release of membrane-bound vesicles and inhibition of tumor cell adhesion by the peptide Neopetrosiamide A

• Published in: PloS one 2010-05, Vol.5 (5), p.e10836-e10836
• Main Authors: Austin, Pamela, Heller, Markus, Williams, David E, McIntosh, Lawrence P, Vogl, A Wayne, Foster, Leonard J, Andersen, Raymond J, Roberge, Michel, Roskelley, Calvin D
• Format: Article
• Language: English
• Subjects: Acids; Actin; Adhesion; Adhesive bonding; Amino acids; Apoptosis; Binding proteins; Biochemistry; Biological activity; Breast cancer; Cancer therapies; Cell adhesion; Cell adhesion & migration; Cell Adhesion - drug effects; Cell Biology/Cell Adhesion; Cell culture; Cell Line, Tumor; Cell Membrane - drug effects; Cell Membrane - metabolism; Cell surface; Cell Surface Extensions - drug effects; Cell Surface Extensions - ultrastructure; Chemical Biology; Cofilin; Cytoplasmic Vesicles - drug effects; Cytoplasmic Vesicles - metabolism; Dismantling; Endoplasmic reticulum; Focal Adhesions - drug effects; Focal Adhesions - metabolism; Homology; Humans; Hydrophobicity; Inhibition; Integrin beta1 - metabolism; Integrins; Kinases; Lipids; Magnetic resonance spectroscopy; Membrane Proteins - metabolism; Membrane vesicles; Metastasis; Microscopy; Moesin; Molecular biology; Muscle proteins; Myosin; Neoplasm Invasiveness; Neoplasms - metabolism; Neoplasms - pathology; NMR spectroscopy; Nuclear magnetic resonance spectroscopy; Oncology/Oncology Agents; Peptides; Peptides, Cyclic - chemistry; Peptides, Cyclic - pharmacology; Physiology; Protein binding; Protein Subunits - metabolism; Proteins; Receptors; Spectroscopy; Temperature; Transferrin; Transferrin receptors; Transferrins; Trends; Tumors; Vesicles
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0010836

Neopetrosiamide A (NeoA) is a 28-amino acid tricyclic peptide originally isolated from a marine sponge as a tumor cell invasion inhibitor whose mechanism of action is unknown. We show that NeoA reversibly inhibits tumor cell adhesion, disassembles focal adhesions in pre-attached cells, and decreases the level of beta1 integrin subunits on the cell surface. NeoA also induces the formation of dynamic, membrane-bound protrusions on the surface of treated cells and the release of membrane-bound vesicles into the culture medium. Proteomic analysis indicates that the vesicles contain EGF and transferrin receptors as well as a number of proteins involved in adhesion and migration including: beta1 integrin and numerous alpha integrin subunits; actin and actin-binding proteins such as cofilin, moesin and myosin 1C; and membrane modulating eps15 homology domain (EHD) proteins. Surface labeling, trafficking inhibition, and real-time imaging experiments all suggest that beta1 integrin-containing vesicles are released directly from NeoA-induced cell surface protrusions rather than from vesicles generated intracellularly. The biological activity of NeoA is dependent on its disulfide bond pattern and NMR spectroscopy indicates that the peptide is globular with a continuous ridge of hydrophobic groups flanked by charged amino acid residues that could facilitate a simultaneous interaction with lipids and proteins in the membrane. NeoA is an anti-adhesive peptide that decreases cell surface integrin levels through a novel, yet to be elucidated, mechanism that involves the release of adhesion molecule-containing vesicles from the cell surface.