title: An antibody inhibitor of the LMO2-protein complex blocks its normal and tumorigenic functions.
abstract: The LIM-domain protein LMO2 is a T-cell oncogenic protein first recognized by gene activation through chromosomal translocations, but it is also responsible for leukaemias arising as secondary, adverse effects in an X-SCID gene therapy trial. There are no specific reagents currently available to analyse the LMO2 multiprotein complex or to combat LMO2-dependent leukaemias. Accordingly, we have isolated an anti-LMO2 single chain Fv antibody fragment to determine if intracellular interference with LMO2-protein complexes can avert LMO2-dependent functions in normal and cancer settings. The anti-LMO2 single chain Fv, obtained using Intracellular Antibody Capture (IAC) technology, is specific for LMO2 among the LIM-only protein family and binds LMO2 through the third and fourth LIM fingers. Using vector-mediated expression of anti-LMO2 scFv, we show inhibition of Lmo2-dependent erythropoiesis but not endothelial development. We also demonstrate inhibition of Lmo2-dependent leukaemia in a mouse T-cell tumourigenesis transplantation assay with retroviral-mediated expression of anti-LMO2 scFv. Our studies establish that interference with the LMO2 multiprotein complex inhibits both normal and tumourigenic roles. The antibody fragment is a tool for dissecting LMO2 function in haematopoiesis and leukaemia and is a lead for development of therapeutics against LMO2-dependent T-ALL.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge, UK.
authors.forename: C-H
authors.initials: CH
authors.lastname: Nam
authors.forename: M N
authors.initials: MN
authors.lastname: Lobato
authors.forename: A
authors.initials: A
authors.lastname: Appert
authors.forename: L F
authors.initials: LF
authors.lastname: Drynan
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: T H
authors.initials: TH
authors.lastname: Rabbitts
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D060588:LIM Domain Proteins; D015458:Leukemia, T-Cell / Q000473:pathology*; D008667:Metalloproteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D051379:Mice
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000906:Antibodies; D004268:DNA-Binding Proteins; D060588:LIM Domain Proteins; C513188:Lmo2 protein, mouse; D008667:Metalloproteins; D049452:Green Fluorescent Proteins