title: Targeting c-kit receptor in neuroblastomas and colorectal cancers using stem cell factor (SCF)-based recombinant bacterial toxins.
abstract: Autocrine activation of c-kit (KIT receptor tyrosine kinase) has been postulated to be a potent oncogenic driver in small cell lung cancer, neuroblastoma (NB), and poorly differentiated colorectal carcinoma (CRC). Although targeted therapy involving tyrosine kinase inhibitors (TKIs) such as imatinib mesylate is highly effective for gastrointestinal stromal tumor carrying V560G c-kit mutation, it does not show much potential for targeting wild-type KIT (WT-KIT). Our study demonstrates the role of stem cell factor (SCF)-based toxin conjugates for targeting WT-KIT-overexpressing malignancies such as NBs and CRCs. We constructed SCF-based recombinant bacterial toxins by genetically fusing mutated form of natural ligand SCF to receptor binding deficient forms of Diphtheria toxin (DT) or Pseudomonas exotoxin A (ETA') and evaluated their efficacy in vitro. Efficient targeting was achieved in all receptor-positive neuroblastoma (IMR-32 and SHSY5Y) and colon cancer cell lines (COLO 320DM, HCT 116, and DLD-1) but not in receptor-negative breast carcinoma cell line (MCF-7) thereby proving specificity. While dose- and time-dependent cytotoxicity was observed in both neuroblastoma cell lines, COLO 320DM and HCT 116 cells, only an anti-proliferative effect was observed in DLD-1 cells. We prove that these novel targeting agents have promising potential as KIT receptor tyrosine kinase targeting system.
authors.affiliation: Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India.
authors.forename: Swati
authors.initials: S
authors.lastname: Choudhary
authors.affiliation: Department of Experimental Medicine and Immunotherapy, Institute of Applied Medical Engineering, University Hospital RWTH Aachen, 52074, Aachen, Germany.
authors.forename: Alessa
authors.initials: A
authors.lastname: Pardo
authors.affiliation: Department of Pharmaceutical Product Development, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, 52074, Aachen, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Rosinke
authors.affiliation: National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
authors.forename: Janendra K
authors.initials: JK
authors.lastname: Batra
authors.affiliation: Department of Experimental Medicine and Immunotherapy, Institute of Applied Medical Engineering, University Hospital RWTH Aachen, 52074, Aachen, Germany. stefan.barth@uct.ac.za.|Department of Pharmaceutical Product Development, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, 52074, Aachen, Germany. stefan.barth@uct.ac.za.|UCT Faculty of Health Sciences, South African Research Chair in Cancer Biotechnology, Cape Town, South Africa. stefan.barth@uct.ac.za.
authors.forename: Stefan
authors.initials: S
authors.lastname: Barth
authors.affiliation: Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India. vermars@iitm.ac.in.
authors.forename: Rama S
authors.initials: RS
authors.lastname: Verma
mesh_terms: D000970:Antineoplastic Agents / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D015179:Colorectal Neoplasms; D004305:Dose-Response Relationship, Drug; D016503:Drug Delivery Systems / Q000379:methods*; D006801:Humans; D009447:Neuroblastoma; D019009:Proto-Oncogene Proteins c-kit / Q000037:antagonists & inhibitors*; D019089:Stem Cell Factor / Q000235:genetics / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D001427:Bacterial Toxins; D019089:Stem Cell Factor; D019009:Proto-Oncogene Proteins c-kit
keywords: Protein-fusion toxins; Stem cell factor; Targeting; c-kit receptor