A novel Monoclonal Antibody against Notch1 Targets Leukemia-associated Mutant Notch1 and Depletes Therapy Resistant Cancer Stem Cells in Solid Tumors

Sharma, Ankur and Gadkari, Rupali A and Ramakanth, Satthenapalli V and Padmanabhan, Krishnanand and Madhumathi, Davanam S and Devi, Lakshmi and Appaji, Lingappa and Aster, Jon C and Rangarajan, Annapoorni and Dighe, Rajan R (2015) A novel Monoclonal Antibody against Notch1 Targets Leukemia-associated Mutant Notch1 and Depletes Therapy Resistant Cancer Stem Cells in Solid Tumors. In: SCIENTIFIC REPORTS, 5 .

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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-offunction'' 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 mu g/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 mu g/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.

Item Type:	Journal Article
Publication:	SCIENTIFIC REPORTS
Publisher:	NATURE PUBLISHING GROUP
Additional Information:	Copy right for this article belongs to the NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Date Deposited:	19 Jul 2015 06:10
Last Modified:	19 Jul 2015 06:10
URI:	http://eprints.iisc.ac.in/id/eprint/51814

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