A novel peptide blocking cancer cell invasion by structure-based drug design

Abstract

Abstract. The receptor for the urokinase-type plasminogen activator (uPA), uPAR, facilitates tumor cell invasion and metastasis by focusing on several ligands, including uPA, integrins and vitronectin. With computational prediction algorithms and structure-based drug design, we identified peptides containing the Gly-Lys-Gly-Glu-Gly-Glu-Gly-Lys-Gly sequence (peptide H1), which strongly interacts with uPAR. The aim of the present study was to investigate the effect of allosteric inhibition at the uPAR interface using a novel synthetic peptide and its function on ovarian cancer cell invasion. The molecular and functional mechanisms of H1 were determined by complementary biochemical and biological methods in the promyeloid U937 cell line as well as ovarian cancer cell lines, including serous carcinoma SKOV3 and clear cell carcinoma TOV21G. The effects of H1 treatment on cancer cell invasion were evaluated in vitro. H1 inhibited cancer cell invasion, without affecting cell viability, accompanied by the suppression of extracellular signal-regulated kinase (ERK)-1 phosphorylation and then matrix metalloproteinase (MMP)-9 expression. H1 failed to block the interaction of uPA-uPAR protein-protein interaction in cells, but antagonized the uPA function. H1 failed to disrupt the uPA-uPAR complex, but abolished the invasion of ovarian cancer cells at least through suppression of the ERK-MMP-9 signaling pathway. Further studies are needed to confirm our observations and to describe the underlying molecular mechanism.

Mechanisms of Resistance to Kinase Inhibitors and Strategies to Prevent the Development of Drug Resistance

“…uPAR is increased in many human cancers and promotes an array of cellular processes that include adhesion, cell spreading, invasion and metastasis. Blocking the interaction of uPAR and its ligand uPA is a promising mechanism for anticancer therapy [96]. uPAR is also able to function through a bidirectional crosstalk with RTKs such as EGFR.…”

“…uPAR is also able to function through a bidirectional crosstalk with RTKs such as EGFR. Several uPAR binding peptides have been designed and formed [96]. The ab initio molecular simulations have clarified that some amino acid residues of amino-terminal fragment (ATF) of uPA play important roles in the specific binding between uPA and uPAR [97][98][99][100].…”

“…We have been manufacturing small-molecule uPAR inhibitors by way of computer-assisted drug discovery and structure-based drug design [96][97][98][99][100]. We found that selective uPAR inhibitors recognize amino acid residues Glu36, Glu134 and Glu135 of uPAR as key anchors to cover the pocket [99].…”

“…The target inhibitors have been generated from ab initio molecular simulations that define a Grand Canonical Monte Carlo (GCMC) Hamiltonian [102]. A series of inhibitors that can bridge the key anchors of uPA-binding pockets were designed and synthesized [96]. Among the synthetic peptides, H1 peptide (Gly-Lys-(Gly)n-Lys-Gly) is a promising candidate for the suppression of cancer invasion in vitro [96].…”

“…A series of inhibitors that can bridge the key anchors of uPA-binding pockets were designed and synthesized [96]. Among the synthetic peptides, H1 peptide (Gly-Lys-(Gly)n-Lys-Gly) is a promising candidate for the suppression of cancer invasion in vitro [96]. Small molecule H1 peptide can recognize three amino acid residues of uPAR as key anchors to cover the uPA binding pocket of uPAR, but does not insert into the pocket.…”