A patch of positively charged residues regulates the efficacy of clinical DR5 antibodies in solid tumors
Gururaj Shivange,
Tanmoy Mondal,
Evan Lyerly,
Sanchita Bhatnagar,
Charles N. Landen,
Shivani Reddy,
Jonathan Kim,
Britney Doan,
Paula Riddle,
Jogender Tushir-Singh
Affiliations
Gururaj Shivange
Laboratory of Novel Biologics, Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA; Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville VA 22908, USA
Tanmoy Mondal
Laboratory of Novel Biologics, Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA; Department of Medical Microbiology and Immunology, University of California School of Medicine, University of California, Davis, Davis, CA 95616, USA; Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville VA 22908, USA
Evan Lyerly
Laboratory of Novel Biologics, Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA; Undergraduate Research Program Volunteers, University of Virginia, Charlottesville VA; Blavatnik Institute, Harvard Medical School, Boston MA
Sanchita Bhatnagar
Department of Medical Microbiology and Immunology, University of California School of Medicine, University of California, Davis, Davis, CA 95616, USA; Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville VA 22908, USA
Charles N. Landen
Department of Gynecology and Oncology, University of Virginia
Shivani Reddy
Laboratory of Novel Biologics, Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA; Undergraduate Research Program Volunteers, University of Virginia, Charlottesville VA
Jonathan Kim
Laboratory of Novel Biologics, Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA; Undergraduate Research Program Volunteers, University of Virginia, Charlottesville VA
Britney Doan
Laboratory of Novel Biologics, Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA; Undergraduate Research Program Volunteers, University of Virginia, Charlottesville VA
Paula Riddle
Laboratory of Novel Biologics, Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA; Undergraduate Research Program Volunteers, University of Virginia, Charlottesville VA
Jogender Tushir-Singh
Laboratory of Novel Biologics, Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA; Department of Medical Microbiology and Immunology, University of California School of Medicine, University of California, Davis, Davis, CA 95616, USA; Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville VA 22908, USA; University of Virginia Comprehensive Cancer Center, Charlottesville VA; UC Davis Comprehensive Cancer Center, University of California School of Medicine, University of California, Davis, Davis, CA 95616, USA; Corresponding author
Summary: Receptor clustering is the first and critical step to activate apoptosis by death receptor-5 (DR5). The recent discovery of the autoinhibitory DR5 ectodomain has challenged the long-standing view of its mechanistic activation by the natural ligand Apo2L. Because the autoinhibitory residues have remained unknown, here we characterize a crucial patch of positively charged residues (PPCR) in the highly variable domain of DR5. The PPCR electrostatically separates DR5 receptors to autoinhibit their clustering in the absence of ligand and antibody binding. Mutational substitution and antibody-mediated PPCR interference resulted in increased apoptotic cytotoxic function. A dually specific antibody that enables sustained tampering with PPCR function exceptionally enhanced DR5 clustering and apoptotic activation and distinctively improved the survival of animals bearing aggressive metastatic and recurrent tumors, whereas clinically tested DR5 antibodies without PPCR blockade function were largely ineffective. Our study provides mechanistic insights into DR5 activation and a therapeutic analytical design for potential clinical success.
