title: Monoclonal Antibodies Targeting LecLex-Related Glycans with Potent Antitumor Activity.
abstract: OBJECTIVE
  To produce antitumor monoclonal antibodies (mAbs) targeting glycans as they are aberrantly expressed in tumors and are coaccessory molecules for key survival pathways.
  
  
  METHODS
  Two mAbs (FG88.2 and FG88.7) recognizing novel tumor-associated Lewis (Le) glycans were produced by immunizations with plasma membrane lipid extracts of the COLO205 cell line.
  
  
  RESULTS
  Glycan array analysis showed that both mAbs bound Le(c)Le(x), di-Le(a), and Le(a)Le(x), as well as Le(a)-containing glycans. These glycans are expressed on both lipids and proteins. Both mAbs showed strong tumor reactivity, binding to 71% (147 of 208) of colorectal, 81% (155 of 192) of pancreatic, 54% (52 of 96) of gastric, 23% (62 of 274) of non-small cell lung, and 31% (66 of 217) of ovarian tumor tissue in combination with a restricted normal tissue distribution. In colorectal cancer, high FG88 glyco-epitope expression was significantly associated with poor survival. The mAbs demonstrated excellent antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC), in addition to direct tumor cell killing via a caspase-independent mechanism. Scanning electron microscopy revealed antibody-induced pore formation. In addition, the mAbs internalized, colocalized with lysosomes, and delivered saporin that killed cells with subnanomolar potency. In vivo, the mAbs demonstrated potent antitumor efficacy in a metastatic colorectal tumor model, leading to significant long-term survival.
  
  
  CONCLUSIONS
  The mAbs direct and immune-assisted tumor cell killing, pan-tumor reactivity, and potent in vivo antitumor efficacy indicate their potential as therapeutic agents for the treatment of multiple solid tumors. In addition, internalization of saporin conjugates and associated tumor cell killing suggests their potential as antibody drug carriers.
authors.affiliation: Division of Cancer and Stem Cells, School of Medicine, City Hospital Campus, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Jia Xin
authors.initials: JX
authors.lastname: Chua
authors.affiliation: Division of Cancer and Stem Cells, School of Medicine, City Hospital Campus, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Mireille
authors.initials: M
authors.lastname: Vankemmelbeke
authors.affiliation: Division of Cancer and Stem Cells, School of Medicine, City Hospital Campus, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Richard S
authors.initials: RS
authors.lastname: McIntosh
authors.affiliation: Division of Cancer and Stem Cells, School of Medicine, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Philip A
authors.initials: PA
authors.lastname: Clarke
authors.affiliation: Division of Cancer and Stem Cells, School of Medicine, City Hospital Campus, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Robert
authors.initials: R
authors.lastname: Moss
authors.affiliation: Division of Cancer and Stem Cells, School of Medicine, City Hospital Campus, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Tina
authors.initials: T
authors.lastname: Parsons
authors.affiliation: Division of Cancer and Stem Cells, School of Medicine, City Hospital Campus, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Ian
authors.initials: I
authors.lastname: Spendlove
authors.affiliation: Section of Surgery, School of Medicine, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Abid M
authors.initials: AM
authors.lastname: Zaitoun
authors.affiliation: Division of Cancer and Stem Cells, School of Medicine, City Hospital Campus, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Madhusudan
authors.affiliation: Division of Cancer and Stem Cells, School of Medicine, City Hospital Campus, University of Nottingham, Nottingham, United Kingdom. lindy.durrant@nottingham.ac.uk.
authors.forename: Lindy G
authors.initials: LG
authors.lastname: Durrant
mesh_terms: D000818:Animals; D058846:Antibodies, Monoclonal, Murine-Derived / Q000378:metabolism / Q000494:pharmacology*; D000920:Antibody-Dependent Cell Cytotoxicity; D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology*; D014408:Biomarkers, Tumor / Q000378:metabolism; D045744:Cell Line, Tumor; D006801:Humans; D007983:Lewis Blood Group Antigens / Q000276:immunology; D008114:Liver Neoplasms, Experimental / Q000188:drug therapy* / Q000556:secondary; D008297:Male; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D011134:Polysaccharides / Q000276:immunology; D023041:Xenograft Model Antitumor Assays
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D007983:Lewis Blood Group Antigens; D011134:Polysaccharides