Design Integrin-targeted Molecular Self-assembling Peptides for Studying Cancer Migration Inhibition

Cancer metastasis, the ability of cancer cell to change position within the tissue through migration and invasion represents the most deadly aspect of cancer. As one of the ongoing challenges in cancer therapy, it’s failed in most treatments. For example, cell surface receptor-integrin that functions as adhesion molecule is well-recognized drug target for anti-metastatic drug development. By targeting the integrin-ligand binding site, antibody, and small molecule antagonists have been commonly used. But these treatments only offer modest response rates on limited cancer types. Therefore, nanotechnology that has been widely applied in biomedical engineering is desired in the cancer metastasis treatment. Inspired by the facts that integrin density, clustering, and redistribution on cell surface are the key spatial features influencing cell motility, we intend to develop a molecular self-assembly (MSA) technology that suppresses cancer metastasis by regulating integrin spatial distribution. To achieve the goal, we designed and synthesized a library of self-assembling integrin ligands composed of 29 peptides made via conjugation of phenylalanine based hydrophobic peptide and various integrin ligands. After confirming that they self-assemble in aqueous solution, we examined these peptides in multiple cancer cell lines and screened out five peptides that exert caner-cell-specific migration. We further examined peptide 5 among the 5 peptides and observed the peptide shows inhibition on cancer invasion, spheroid growth and spreading. We explored the molecular mechanism of the peptide on migration inhibition and found the the self-assembly of the peptide forms nanostructured microdomain as nano-biointerface on cancer cell membrane. We examined the molecular consequences of the bio-nanointerface on mechanotransduction-related proteins, especially the Hippo signaling related ones. Finally, the peptide is applied in xenograft tumor models in mice to examine the efficacy of tumor suppression effect and the molecular consequences in vivo. The research work presented in the thesis is intend to establish an easy and practical strategy for anti-metastatic drug development, and illustrate how basic biochemical insights can be exploited as the basis for a nano-biointerface fabrication technology which links nanoscale protein activities to molecular biological activities to suppress metastasis.Okinawa Institute of Science and Technology Graduate Universit

Control cell migration by engineering integrin ligand assembly

Advances in mechanistic understanding of integrin-mediated adhesion highlight the importance of precise control of ligand presentation in directing cell migration. Top-down nanopatterning limited the spatial presentation to sub-micron placing restrictions on both fundamental study and biomedical applications. To break the constraint, here we propose a bottom-up nanofabrication strategy to enhance the spatial resolution to the molecular level using simple formulation that is applicable as treatment agent. Via self-assembly and co-assembly, precise control of ligand presentation is succeeded by varying the proportions of assembling ligand and nonfunctional peptide. Assembled nanofilaments fulfill multi-functions exerting enhancement to suppression effect on cell migration with tunable amplitudes. Self-assembled nanofilaments possessing by far the highest ligand density prevent integrin/actin disassembly at cell rear, which expands the perspective of ligand-density-dependent-modulation, revealing valuable inputs to therapeutic innovations in tumor metastasis