Sept. 10, 2009 INBRE Steering Committee Development and Screening of Transition Metal Complexes as CXCR4 Antagonists Dr. Tim Hubin Department of Chemistry and Physics
Important role in embryonic development: Organogenesis (liver, heart) Stem cell movement Cerebellar neuron migration (formation of brain) Seven transmembrane G-protein-coupled receptor 27% of amino acids are Asp, His or Tyr. Expressed on : Leukocytes T-lymphocytes Endothelial cells Neuronal cells CXCR4 chemokine receptor Khan, A.; Greenman, J.; Archibald, S. J. Curr. Med. Chem. 2007, 14, 2257.
CXCL12 • 67 residue highly basic protein • Only known natural ligand (chemokine) for CXCR4 • Secreted by stromal, lung and liver cells, and lymph nodes • Attracts leukocytes to sites of inflammation and lymphoid organs
Disease states • Role in disease • Human Immunodeficiency Virus • Tumour growth and metastasis • Stem cell mobilization • Autoimmune disorders (rheumatoid arthritis)
Inhibitors against 5 steps of HIV replication cycle • Still need for new targets • CXCR4-antagonists • Prototype bicyclams AMD3100
Blocking receptor functions CXCL12/HIV Drug Cell
Over expression of CXCR4 receptors Cancer cell Normal cell
CXCR4 antagonists • Peptide based • Side chains protonated at physiological pH
Plerixafor/ AMD3100 • The first bicyclams were discovered as impurities in a sample of cyclam. Amongst the most active anti-HIV agents in vitro. • Anti-HIV clinical testing discontinued. • Stem cell mobilization For example: Mol. Pharm., 1999, 55, 67. J. Med. Chem., 1995, 38, 366. Biochemistry, 2003, 42, 715. AMD3100
Molecular shape Bosnich, B.; Poon, C. K.; Tobe, M. L. Inorg. Chem.,1965, 4,1102
Restrict to one configuration Only cis V Only trans
Side-Bridged Synthesis Reagents: (a) acetonitrile, RT, 24 h (89%); (b) NaBH4, EtOH reflux, 1 h (65%).
AMD3100 Lewis, E. A.; Hubin, T. J.; Archibald, S. J. European Patent 1765826A2 .
Copper(II) coordination Axial Equatorial
Side bridged (SB) Cross bridged (CB) Axial Equatorial Cu-O1 2.28(1) Å Cu-O1 1.95(1) Å
Selecting the cell line • Use anti-CXCR4 antibodies to screen cell lines • Two identified Jurkat and Molt-4 • Four anti-CXCR4 antibodies used (variation in binding epitopes)
Key Name Parameter - control.001 FL1-H + Control 717.019 FL1-H L2 717.010 FL1-H L1 717.009 FL1-H Binding by flow cytometry Fluorescent antibody Receptor specific antibody Drug molecule CXCR4
Summary of mAb 12G5 binding to CXCR4 in the presence of bound antagonists.
Residence time G. McRobbie, A. Khan, G. Nicholson, L. Madden, J. Greenman C. Pannecouque, E. De Clercq, T. J. Hubin and S. J. Archibald, J. Am. Chem. Soc, 2009, 3416.
ANTI-CANCER ACTIVITY Invasion assays • Cell invasion assays in response to a chemokine gradient. • Initially used SJSA cells. • Experiments run in presence and absence of antagonist.
CXCL12 Control Drug/ no CXCL12 Drug + CXCL12
CONCLUSIONS • Axial vs. equatorial coordination makes all the difference in copper(II) containing protein binding drugs. • Promising early anti-metastatic properties in vitro. In vivo testing to follow.
Current research group: Courtney Garcia (Pre-Med) Josh Priddle (Pre-Med) Desiray Cannon (Pre-Med) Brooke Shockey (Pre-Med) Katherine Coats (Chemistry) Past members: Robert Ullom—University of Kansas (Medicine) TauLyn Snell—Wichita State University (PA) Joe Blas—Creighton (Medicine) Danny Maples—OSU (Chemistry) Randall Maples—OSU (Chemistry) Dallas Matz—Arizona State University (Chemistry) Mike McClain—OU (Chemistry) Amy Cain—U. British Columbia (Chemistry) Neil Funwie—OU (Petroleum Engineering) Orry Birdsong—UT Galveston (Medicine) Kimberly Roewe—OSU (Chemistry) Kiet Ngyuen—SWOSU (Pharmacy) Acknowledgements Funding • OK-INBRE (NIH) • Research Corporation • SWOSU • Dr. Steve Archibald (Hull) • Abid Khan • Prof. Erik De Clercq (Leuven) • Dr. Christophe Pannecouque(Leuven) • Dr. Dominique Schols (Leuven) • Prof Tony Ng (KCL)