Structural characterisation of high affinity Siglec-2 (CD22) ligands in complex with whole Burkitt's lymphoma (BL) Daudi cells by NMR spectroscopy.
Siglec-2 undergoes constitutive endocytosis and is a drug target for autoimmune diseases and B cell-derived malignancies, including hairy cell leukaemia, marginal zone lymphoma, chronic lymphocytic leukaemia and non-Hodgkin's lymphoma (NHL). An alternative to current antibody-based therapies is the use of liposomal nanoparticles loaded with cytotoxic drugs and decorated with Siglec-2 ligands. We have recently designed the first Siglec-2 ligands (9-biphenylcarboxamido-4-meta-nitrophenyl-carboxamido-Neu5Acα2Me, 9-BPC-4-mNPC-Neu5Acα2Me) with simultaneous modifications at C-4 and C-9 position. In the current study we have used Saturation Transfer Difference (STD) NMR spectroscopy to monitor the binding of 9-BPC-4-mNPC-Neu5Acα2Me to Siglec-2 present on intact Burkitt's lymphoma Daudi cells. Pre-treatment of cells with periodate resulted in significantly higher STD NMR signal intensities for 9-BPC-4-mNPC-Neu5Acα2Me as the cells were more susceptible to ligand binding because cis-binding on the cell surface was removed. Quantification of STD NMR effects led to a cell-derived binding epitope of 9-BPC-4-mNPC-Neu5Acα2Me that facilitated the design and synthesis of C-2, C-3, C-4 and C-9 tetra-substituted Siglec-2 ligands showing an 88-fold higher affinity compared to 9-BPC-Neu5Acα2Me. This is the first time a NMR-based binding study of high affinity Siglec-2 (CD22) ligands in complex with whole Burkitt's lymphoma Daudi cells has been described that might open new avenues in developing tailored therapeutics and personalised medicine.
Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland, 4222, Australia.
Paul D
PD
Madge
Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland, 4222, Australia.
Andrea
A
Maggioni
Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland, 4222, Australia.
Mauro
M
Pascolutti
Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland, 4222, Australia.
Moein
M
Amin
Centre for Biomolecular Interactions Bremen, Department of Biology and Chemistry, University of Bremen, 28334 Bremen, Germany.
Mario
M
Waespy
Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland, 4222, Australia.
Bernadette
B
Bellette
Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland, 4222, Australia.
Robin J
RJ
Thomson
Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland, 4222, Australia.|Centre for Biomolecular Interactions Bremen, Department of Biology and Chemistry, University of Bremen, 28334 Bremen, Germany.
Sørge
S
Kelm
Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland, 4222, Australia.
Mark
M
von Itzstein
Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland, 4222, Australia.
Thomas
T
Haselhorst
D002051:Burkitt Lymphoma / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D000939:Epitopes / Q000378:metabolism; D005434:Flow Cytometry; D057809:HEK293 Cells; D006801:Humans; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D019158:N-Acetylneuraminic Acid / Q000737:chemistry / Q000378:metabolism; D010504:Periodic Acid / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D051918:Sialic Acid Binding Ig-like Lectin 2 / Q000737:chemistry* / Q000378:metabolism*; D020349:Surface Plasmon Resonance; D014162:Transfection
D000939:Epitopes; D008024:Ligands; D011994:Recombinant Proteins; D051918:Sialic Acid Binding Ig-like Lectin 2; D010504:Periodic Acid; C009288:metaperiodate; D019158:N-Acetylneuraminic Acid