Bi-213-anti-EGFR radioimmunoconjugates and X-ray irradiation trigger different cell death pathways in squamous cell carcinoma cells

Pickhard, Anja and Piontek, Guido and Seidl, Christof and Kopping, Samuel and Blechert, Birgit and Misslbeck, Martin and Brockhoff, Gero and Bruchertseifer, Frank and Morgenstern, Alfred and Essler, Markus (2014) Bi-213-anti-EGFR radioimmunoconjugates and X-ray irradiation trigger different cell death pathways in squamous cell carcinoma cells. NUCLEAR MEDICINE AND BIOLOGY, 41 (1). pp. 68-76. ISSN 0969-8051, 1872-9614

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Abstract

Introduction: Treatment of patients with squamous cell carcinoma of head and neck is hampered by resistance of tumor cells to irradiation. Additional therapies enhancing the effect of X-ray irradiation may be beneficial. Antibodies targeting EGFR have been shown to improve the efficacy of radiation therapy. Therefore, we analyzed cytotoxicity of Bi-213-anti-EGFR immunoconjugates in combination with X-ray irradiation. Methods: The monoclonal anti-EGFR antibody matuzumab was coupled to CHX-A"-DTPA forming stable complexes with Bi-213. Cytotoxicity of X-ray radiation, of treatment with Bi-213-anti-EGFR monoclonal antibodies (MAb) or of a combined treatment regimen was assayed using cell proliferation and colony formation assays in UD-SCC5 cells. Key proteins of cell-cycle arrest and cell death were examined by Western blot analysis. Cell cycle analysis was performed by flow cytometry. DNA double-strand breaks were detected via gamma H2AX and quantified using Definiens (TM) software. Results: Irradiation with X-rays or treatment with Bi-213-anti-EGFR-MAb resulted in median lethal dose (LD50) values of 12 Gy or 130 kBq/mL, respectively. Treatment with 37 kBq/mL of Bi-213-anti-EGFR-MAb or 2 Gy of X-rays had only little effect on colony formation of UD-SCC5 cells. In contrast, a combined treatment regimen (37 kBq/mL plus 2 Gy) significantly decreased colony formation and enhanced the formation of DNA double-strand breaks. As revealed by flow cytometry, radiation treatments caused accumulation of cells in the GO/G1 phase. Both treatment with Bi-213-anti-EGFR immunoconjugates and application of the combined treatment regimen triggered activation of genes of signaling pathways involved in cell-cycle arrest and induction of apoptosis like p21/Waf, GADD45, Puma and Box, which were only marginally modulated by X-ray irradiation of cells. Conclusions: Bi-213-anti-EGFR-MAb enhances cytotoxicity of X-ray irradiation in UD-SCC5 cells most probably due to effective induction of DNA double-strand breaks. Induction of genes involved in cell-cycle arrest and cell death is almost exclusively due to Bi-213-anti-EGFR-MAb and seems to be independent of p53 function. (C) 2014 Elsevier Inc. All rights reserved.

Item Type: Article
Uncontrolled Keywords: P53 TUMOR-SUPPRESSOR; NECK-CANCER; ALPHA-RADIOIMMUNOTHERAPY; PLUS CETUXIMAB; DNA-DAMAGE; HUMAN HEAD; THERAPY; IMMUNOTHERAPY; CHEMOTHERAPY; Head and neck squamous cell carcinoma; alpha-emitter Bi-213; Radioimmunotherapy; UD-SCC5 cells; Cytotoxicity; Cell-cycle arrest; Apoptosis
Subjects: 600 Technology > 610 Medical sciences Medicine
Divisions: Medicine > Lehrstuhl für Frauenheilkunde und Geburtshilfe (Schwerpunkt Frauenheilkunde)
Depositing User: Dr. Gernot Deinzer
Date Deposited: 04 Dec 2019 09:07
Last Modified: 04 Dec 2019 09:07
URI: https://pred.uni-regensburg.de/id/eprint/11146

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