title: A novel Monoclonal Antibody against Notch1 Targets Leukemia-associated Mutant Notch1 and Depletes Therapy Resistant Cancer Stem Cells in Solid Tumors.
abstract: Higher Notch signaling is known to be associated with hematological and solid cancers. We developed a potential immunotherapeutic monoclonal antibody (MAb) specific for the Negative Regulatory Region of Notch1 (NRR). The MAb604.107 exhibited higher affinity for the "Gain-of-function" mutants of Notch1 NRR associated with T Acute lymphoblastic Leukemia (T-ALL). Modeling of the mutant NRR with 12 amino-acid insertion demonstrated "opening" resulting in exposure of the S2-cleavage site leading to activated Notch1 signaling. The MAb, at low concentrations (1-2 μg/ml), inhibited elevated ligand-independent Notch1 signaling of NRR mutants, augmented effect of Thapsigargin, an inhibitor of mutant Notch1, but had no effect on the wild-type Notch1. The antibody decreased proliferation of the primary T-ALL cells and depleted leukemia initiating CD34/CD44 high population. At relatively high concentrations, (10-20 μg/ml), the MAb affected Notch1 signaling in the breast and colon cancer cell lines. The Notch-high cells sorted from solid-tumor cell lines exhibited characteristics of cancer stem cells, which were inhibited by the MAb. The antibody also increased the sensitivity to Doxorubucinirubicin. Further, the MAb impeded the growth of xenografts from breast and colon cancer cells potentiated regression of the tumors along with Doxorubucin. Thus, this antibody is potential immunotherapeutic tool for different cancers.
authors.affiliation: Department of Molecular Reproduction Development and Genetics, Indian Institute of Science Bangalore, Karnataka, India.
authors.forename: Ankur
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science Bangalore, Karnataka, India.
authors.forename: Rupali A
authors.initials: RA
authors.lastname: Gadkari
authors.affiliation: Department of Molecular Reproduction Development and Genetics, Indian Institute of Science Bangalore, Karnataka, India.
authors.forename: Satthenapalli V
authors.initials: SV
authors.lastname: Ramakanth
authors.affiliation: Department of Molecular Reproduction Development and Genetics, Indian Institute of Science Bangalore, Karnataka, India.
authors.forename: Krishnanand
authors.initials: K
authors.lastname: Padmanabhan
authors.affiliation: Department of Pathology, Kidwai Memorial Institute of Oncology, Bangalore, Karnataka, India.
authors.forename: Davanam S
authors.initials: DS
authors.lastname: Madhumathi
authors.affiliation: Department of Pathology, Kidwai Memorial Institute of Oncology, Bangalore, Karnataka, India.
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Devi
authors.affiliation: Department of Pediatric Oncology, Kidwai Memorial Institute of Oncology, Bangalore, Karnataka, India.
authors.forename: Lingappa
authors.initials: L
authors.lastname: Appaji
authors.affiliation: Department of Pathology, Brigham &Women's Hospital, Harvard Medical School, Boston, USA.
authors.forename: Jon C
authors.initials: JC
authors.lastname: Aster
authors.affiliation: Department of Molecular Reproduction Development and Genetics, Indian Institute of Science Bangalore, Karnataka, India.
authors.forename: Annapoorni
authors.initials: A
authors.lastname: Rangarajan
authors.affiliation: Department of Molecular Reproduction Development and Genetics, Indian Institute of Science Bangalore, Karnataka, India.
authors.forename: Rajan R
authors.initials: RR
authors.lastname: Dighe
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology* / Q000627:therapeutic use; D000915:Antibody Affinity; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D004317:Doxorubicin / Q000494:pharmacology / Q000627:therapeutic use; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D008819:Mice, Nude; D009154:Mutation; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000502:physiology*; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D051881:Receptor, Notch1 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; C497761:NOTCH1 protein, human; D051881:Receptor, Notch1; C000606219:monoclonal antibody 604.107; D004317:Doxorubicin