Structural Basis for Eliciting a Cytotoxic Effect in HER2-Overexpressing Cancer Cells via Binding to the Extracellular Domain of HER2

Jöst, Christian; Schilling, Johannes; Tamaskovic, Rastislav; Schwill, Martin; Honegger, Annemarie; Plückthun, Andreas

doi:10.1016/j.str.2013.08.020

Cited by 115 publications

(142 citation statements)

References 60 publications

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“…However, our SPR data suggests that peptide 1 as well as its conjugates 4 and 7 bind to EGFR domain 1 in the absence of ligand EGF, indicating that the conjugates also bind to EGFR in closed conformation. Such models have been proposed in the literature for binding of bi-specific affibody ligands that target EGFR and HER2 dimers [46], as well as HER2 dimers in open and closed conformations [47]. Hence, our SPR and modeling studies suggest that conjugates 4 and 7 can bind to monomer EGFR, as well as dimer EGFR, in open or closed conformations.…”

Section: Resultsmentioning

confidence: 61%

Targeting of the epidermal growth factor receptor with mesoporphyrin IX-peptide conjugates

Fontenot

Ongarora

LeBlanc

et al. 2016

J. Porphyrins Phthalocyanines

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The synthesis and in vitro evaluation of four mesoporphyrin IX-peptide conjugates designed to target EGFR, over-expressed in colorectal and other cancers, are reported. Two peptides with known affinity for EGFR, LARLLT (1) and GYHWYGYTPQNVI (2), were conjugated to mesoporphyrin IX (MPIX, 3) via one or both the propionic side chains, directly (4, 5) or with a triethylene glycol spacer (7, 8). The conjugates were characterized using NMR, MS, CD, SPR, UV-vis and fluorescence spectroscopies. Energy minimization and molecular dynamics suggest different conformations for the conjugates. SPR studies show that conjugate 4, bearing two LARLLT with no PEG spacers, has the greatest affinity for binding to EGFR, followed by conjugate 7 with two PEG and two LARLLT sequences. Molecular modeling and docking studies suggest that both conjugates 4 and 7 can bind to monomer and dimer EGFR in open and closed conformations. The cytotoxicity and cellular targeting ability of the conjugates were investigated in human HEp2 cells over-expressing EGFR. All conjugates showed low dark- and photo-toxicities. The cellular uptake was highest for conjugates 4 and 8 and lowest for 7 bearing two LARLLT linked via PEG groups, likely due to decreased hydrophobicity. Among the conjugates investigated 4 is the most efficient EGFR-targeting agent, and therefore the most promising for the detection of cancers that over-express EGFR.

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Section: Resultsmentioning

confidence: 61%

Targeting of the epidermal growth factor receptor with mesoporphyrin IX-peptide conjugates

Fontenot

Ongarora

LeBlanc

et al. 2016

J. Porphyrins Phthalocyanines

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“…Other multivalent antibody-based or designed ankyrin repeat proteins (DARPins) that target HER2 or HER3 have been recently described 53 - 55 . Specifically, a tetravalent antibody (MM-141), with a similar design to TAb6 in the current study, that targets both HER3 and IGF-1R has been shown to have anti-proliferative effects both in vitro and in vivo 54 .…”

Section: Discussionmentioning

confidence: 84%

Engineering multivalent antibodies to target heregulin-induced HER3 signaling in breast cancer cells

Kang

Poovassery

Bansal

et al. 2013

mAbs

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The use of antibodies in therapy and diagnosis has undergone an unprecedented expansion during the past two decades. This is due in part to innovations in antibody engineering that now offer opportunities for the production of “second generation” antibodies with multiple specificities or altered valencies. The targeting of individual components of the human epidermal growth factor receptor (HER)3-PI3K signaling axis, including the preferred heterodimerization partner HER2, is known to have limited anti-tumor effects. The efficacy of antibodies or small molecule tyrosine kinase inhibitors (TKIs) in targeting this axis is further reduced by the presence of the HER3 ligand, heregulin. To address these shortcomings, we performed a comparative analysis of two distinct approaches toward reducing the proliferation and signaling in HER2 overexpressing tumor cells in the presence of heregulin. These strategies both involve the use of engineered antibodies in combination with the epidermal growth factor receptor (EGFR)/HER2 specific TKI, lapatinib. In the first approach, we generated a bispecific anti-HER2/HER3 antibody that, in the presence of lapatinib, is designed to sequester HER3 into inactive HER2-HER3 dimers that restrain HER3 interactions with other possible dimerization partners. The second approach involves the use of a tetravalent anti-HER3 antibody with the goal of inducing efficient HER3 internalization and degradation. In combination with lapatinib, we demonstrate that although the multivalent HER3 antibody is more effective than its bivalent counterpart in reducing heregulin-mediated signaling and growth, the bispecific HER2/HER3 antibody has increased inhibitory activity. Collectively, these observations provide support for the therapeutic use of bispecifics in combination with TKIs to recruit HER3 into complexes that are functionally inert.

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“…This feature may allow new fusion formats that target two distinct ERBB2-epitopes to be constructed. A similar strategy using designed ankyrin repeat proteins targeted to different epitopes on ERBB2 has shown a high potential for cancer treatment in vitro that did not rely on the addition of functional payloads [31]. Furthermore, binding assays on ERBB2-positive human cancer cells demonstrated that the ADAPTs specifically recognized the native receptor (Figure 4C).…”

Section: Discussionmentioning

confidence: 97%

Engineering of Bispecific Affinity Proteins with High Affinity for ERBB2 and Adaptable Binding to Albumin

et al. 2014

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The epidermal growth factor receptor 2, ERBB2, is a well-validated target for cancer diagnostics and therapy. Recent studies suggest that the over-expression of this receptor in various cancers might also be exploited for antibody-based payload delivery, e.g. antibody drug conjugates. In such strategies, the full-length antibody format is probably not required for therapeutic effect and smaller tumor-specific affinity proteins might be an alternative. However, small proteins and peptides generally suffer from fast excretion through the kidneys, and thereby require frequent administration in order to maintain a therapeutic concentration. In an attempt aimed at combining ERBB2-targeting with antibody-like pharmacokinetic properties in a small protein format, we have engineered bispecific ERBB2-binding proteins that are based on a small albumin-binding domain. Phage display selection against ERBB2 was used for identification of a lead candidate, followed by affinity maturation using second-generation libraries. Cell surface display and flow-cytometric sorting allowed stringent selection of top candidates from pools pre-enriched by phage display. Several affinity-matured molecules were shown to bind human ERBB2 with sub-nanomolar affinity while retaining the interaction with human serum albumin. Moreover, parallel selections against ERBB2 in the presence of human serum albumin identified several amino acid substitutions that dramatically modulate the albumin affinity, which could provide a convenient means to control the pharmacokinetics. The new affinity proteins competed for ERBB2-binding with the monoclonal antibody trastuzumab and recognized the native receptor on a human cancer cell line. Hence, high affinity tumor targeting and tunable albumin binding were combined in one small adaptable protein.

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Structural Basis for Eliciting a Cytotoxic Effect in HER2-Overexpressing Cancer Cells via Binding to the Extracellular Domain of HER2

Cited by 115 publications

References 60 publications

Targeting of the epidermal growth factor receptor with mesoporphyrin IX-peptide conjugates

Targeting of the epidermal growth factor receptor with mesoporphyrin IX-peptide conjugates

Engineering multivalent antibodies to target heregulin-induced HER3 signaling in breast cancer cells

Engineering of Bispecific Affinity Proteins with High Affinity for ERBB2 and Adaptable Binding to Albumin

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