In silico driven redesign of a clinically relevant antibody for the treatment of GD2 positive tumors.

Mahiuddin Ahmed,Yehuda Goldgur,Nai-Kong V Cheung,Hong-Fen Guo,Jian Hu,Michael P Bachmann

doi:10.1371/journal.pone.0063359

Mahiuddin Ahmed, Yehuda Goldgur + Show 4 more

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https://doi.org/10.1371/journal.pone.0063359

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Journal: PloS one	Publication Date: May 16, 2013
Citations: 57	License type: CC BY 4.0

Affiliation: Memorial Sloan Kettering Cancer Center

Abstract

Ganglioside GD2 is a cell surface glycolipid that is highly expressed on cancer cells of neuroectodermal origin, including neuroblastoma, retinoblastoma, melanoma, sarcomas, brain tumors and small cell lung cancer. Monoclonal antibodies (MoAb) that target GD2 have shown clinical efficacy in the treatment of GD2 expressing tumors, and are expected to be the new standard of care for the treatment of pediatric neuroblastoma. In this study, the crystal structure of anti-GD2 murine MoAb 3F8 was solved to 1.65 Å resolution and used as a template for molecular docking simulations of its antigen, the penta-saccharide head group of GD2. Molecular docking revealed a binding motif composed of 12 key interacting amino acid side-chains, involving an extensive network of interactions involving main-chain and side-chain hydrogen bonding, two Pi – CH interactions, and an important charged interaction between Arg95 of the H3 loop with the penultimate sialic acid residue of GD2. Based on in silico scanning mutagenesis of the 12 interacting amino acids from the docked 3F8:GD2 model, a single point mutation (Heavy Chain: Gly54Ile) was engineered into a humanized 3F8 (hu3F8) MoAb and found to have a 6–9 fold enhancement in antibody-dependent cell-mediated cytotoxicity of neuroblastoma and melanoma cell lines. With enhanced tumor-killing properties, the re-engineered hu3F8 has the potential be a more effective antibody for the treatment of GD2-positive tumors.

Highlights

Gangliosides are sialic acid containing cell surface glycolipids that have been utilized as targets for cancer immunotherapy [1]
The structure of GD2 consists of a pentasaccharide head group and a ceramide tail that is embedded in the cell surface membrane (Figure 1)
The blood brain barrier prevents intravenously administered anti-GD2 monoclonal antibody (MoAb) from entering the central nervous system (CNS), making GD2 an ideal target for neuroectodermal tumors outside of the CNS

Summary

Introduction

Gangliosides are sialic acid containing cell surface glycolipids that have been utilized as targets for cancer immunotherapy [1]. The disialoganglioside GD2, in particular, is a glycolipid antigen that is highly expressed on tumors of both pediatric and adult cancers, including neuroblastoma, retinoblastoma, melanoma, brain tumors, sarcomas and small cell lung cancer [2]. The structure of GD2 consists of a pentasaccharide head group (containing a glucose Glc, galactose Gal, a branched N-acetylgalactosamine GalNAc, and two sialic acid units NeuNAc1 and NeuNAc2) and a ceramide tail that is embedded in the cell surface membrane (Figure 1). GD2 expression in normal tissues is restricted primarily to the central nervous system, with low levels in peripheral nerves and skin melanocytes [5]. The blood brain barrier prevents intravenously administered anti-GD2 MoAbs from entering the central nervous system (CNS), making GD2 an ideal target for neuroectodermal tumors outside of the CNS. Acute toxicities of anti-GD2 MoAb therapy include hypertension, pain, fever and urticaria, long-term toxicities have been uncommon [2]

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