Identification of Placenta Growth Factor Determinants for Binding and Activation of Flt-1 Receptor

Errico, Michela; Riccioni, Teresa; Iyer, Shalini; Pisano, Claudio; Acharya, K. Ravi; Persico, M. Graziella; Falco, Sandro De

doi:10.1074/jbc.m401418200

Cited by 50 publications

(75 citation statements)

References 35 publications

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“…5). Mutation of the two corresponding residues Asp 63 and Glu 64 in PlGF-1 to alanine gave rise to a mutant defective for VEGFR-1 binding (50). Similarly, in VEGF-A, loop L2 with Asp 63 , Glu 64 , and Glu 67 was a critical determinant for high affinity binding to VEGFR-1 (48).…”

Section: Discussionmentioning

confidence: 99%

“…At 100 nM, VE R46I and VE L13 showed equal potential to displace 125 I-PlGF-1 from the receptor, whereas at lower concentrations, we observed clear differences. With an EC 50 of 4.2 (3.7-4.7) nM, VE L13 binding to VEGFR-1 was more than 8-fold better than that of VE R46I (EC 50 34.8 (31.9 -38.0) nM; Fig. 3E).…”

Section: Receptor Binding Properties Of Vegf-e/plgf Chimericmentioning

confidence: 99%

“…3D). Substitution of Arg 46 to Ile in L1 of VEGF-E resulted in a 5-fold decrease of the EC 50 . However, none of these VEGF-E variants was as potent as VEGF-A 165 in displacing the radioligand from VEGFR-2 on PAE cells.…”

Section: Receptor Binding Properties Of Vegf-e/plgf Chimericmentioning

confidence: 99%

“…This shows that exchanging either one or both of these loops abolished binding to VEGFR-2. Interestingly, competition with VE R46I 50 values were determined with Prism 4.0 software using nonlinear regression. C, binding affinities were determined by surface plasmon resonance using a BIAcore 3000 apparatus.…”

Section: Receptor Binding Properties Of Vegf-e/plgf Chimericmentioning

confidence: 99%

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Crystal Structure of the Orf Virus NZ2 Variant of Vascular Endothelial Growth Factor-E

Pieren

Prota

Ruch

et al. 2006

Journal of Biological Chemistry

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Mammalian vascular endothelial growth factors constitute a family of polypeptides, vascular endothelial growth factor (VEGF)-A, -B, -C, -D and placenta growth factor (PlGF), that regulate blood and lymphatic vessel development. VEGFs bind to three types of receptor tyrosine kinases, VEGF receptors 1, 2, and 3, that are predominantly expressed on endothelial and some hematopoietic cells. Pox viruses of the Orf family encode highly related proteins called VEGF-E that show only 25-35% amino acid identity with VEGF-A but bind with comparable affinity to VEGFR-2. The crystal structure of VEGF-E NZ2 described here reveals high similarity to the known structural homologs VEGF-A, PlGF, and the snake venoms Vammin and VR-1, which are all homodimers and contain the characteristic cysteine knot motif. Distinct conformational differences are observed in loop L1 and particularly in L3, which contains a highly flexible GS-rich motif that differs from all other structural homologs. Based on our structure, we created chimeric proteins by exchanging selected segments in L1 and L3 with the corresponding sequences from PlGF. Single loop mutants did not bind to either receptor, whereas a VEGF-E mutant in which both L1 and L3 were replaced gained affinity for VEGFR-1, illustrating the possibility to engineer receptor-specific chimeric VEGF molecules. In addition, changing arginine 46 to isoleucine in L1 significantly increased the affinity of VEGF-E for both VEGF receptors.

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Section: Discussionmentioning

confidence: 99%

Section: Receptor Binding Properties Of Vegf-e/plgf Chimericmentioning

confidence: 99%

Section: Receptor Binding Properties Of Vegf-e/plgf Chimericmentioning

confidence: 99%

Section: Receptor Binding Properties Of Vegf-e/plgf Chimericmentioning

confidence: 99%

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Crystal Structure of the Orf Virus NZ2 Variant of Vascular Endothelial Growth Factor-E

Pieren

Prota

Ruch

et al. 2006

Journal of Biological Chemistry

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“…Anti-hVEGF or anti-mVEGF polyclonal antibody (R&D Systems, Minneapolis, MN), diluted at 1 g/ml in PBS, pH 7.5, was used to coat a 96-well plate, 100 l/well, overnight at 4°C. Washings, dilutions of standards (recombinant hVEGF or mVEGF), and samples (serum of killed mice), biotinylation, and mix with preformed avidin and biotinylated HRP macromolecular complex (Vectastain kit) were described (35). The absorbance was measured at 490 nm on a microplate reader (Bio-Rad, Hercules, CA).…”

mentioning

confidence: 99%

TLR9 agonist acts by different mechanisms synergizing with bevacizumab in sensitive and cetuximab-resistant colon cancer xenografts

Damiano¹,

Caputo²,

Garofalo³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Synthetic agonists of Toll-like receptor 9 (TLR9), a class of agents that induce specific immune response, exhibit antitumor activity and are currently being investigated in cancer patients. Intriguingly, their mechanisms of action on tumor growth and angiogenesis are still incompletely understood. We recently discovered that a synthetic agonist of TLR9, immune modulatory oligonucleotide (IMO), acts by impairing epidermal growth factor receptor (EGFR) signaling and potently synergizes with anti-EGFR antibody cetuximab in GEO human colon cancer xenografts, whereas it is ineffective in VEGF-overexpressing cetuximab-resistant GEO cetuximab-resistant (GEO-CR) tumors. VEGF is activated by EGFR, and its overexpression causes resistance to EGFR inhibitors. Therefore, we used IMO and the anti-VEGF antibody bevacizumab as tools to study IMO's role on EGFR and angiogenesis and to explore its therapeutic potential in GEO, LS174T, and GEO-CR cancer xenografts. We found that IMO enhances the antibody-dependent cell-mediated cytotoxicity (ADCC) activity of cetuximab, that bevacizumab has no ADCC, and IMO is unable to enhance it. Nevertheless, the IMO-plus-bevacizumab combination synergistically inhibits the growth of GEO and LS174T as well as of GEO-CR tumors, preceded by inhibition of signaling protein expression, microvessel formation, and human, but not murine, VEGF secretion. Moreover, IMO inhibited the growth, adhesion, migration, and capillary formation of VEGF-stimulated endothelial cells. The antitumor activity was irrespective of the TLR9 expression on tumor cells. These studies demonstrate that synthetic agonists of TLR9 interfere with growth and angiogenesis also by EGFR-and ADCCindependent mechanisms affecting endothelial cell functions and provide a strong rationale to combine IMO with bevacizumab and EGFR inhibitory drugs in colon cancer patients.angiogenesis ͉ cancer therapy ͉ growth factor receptors

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Protein Kinase Structure, Function, and Regulation

Matthews¹,

Gerritsen²

2010

Targeting Protein Kinases for Cancer Therapy

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Identification of Placenta Growth Factor Determinants for Binding and Activation of Flt-1 Receptor

Cited by 50 publications

References 35 publications

Crystal Structure of the Orf Virus NZ2 Variant of Vascular Endothelial Growth Factor-E

Crystal Structure of the Orf Virus NZ2 Variant of Vascular Endothelial Growth Factor-E

TLR9 agonist acts by different mechanisms synergizing with bevacizumab in sensitive and cetuximab-resistant colon cancer xenografts

Protein Kinase Structure, Function, and Regulation

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