Chia-Jung Busch1, Marie Sophie Kröger2, Jana Jensen2, Malte Kriegs3, Fruzsina Gatzemeier2, Cordula Petersen4, Adrian Münscher1, Kai Rothkamm3, Thorsten Rieckmann5. 1. Department of Otolaryngology and Head and Neck Surgery, University Medical Center Hamburg Eppendorf, Germany. 2. Department of Otolaryngology and Head and Neck Surgery, University Medical Center Hamburg Eppendorf, Germany; Laboratory of Radiobiology & Experimental Radiation Oncology, University Medical Center Hamburg Eppendorf, Germany. 3. Laboratory of Radiobiology & Experimental Radiation Oncology, University Medical Center Hamburg Eppendorf, Germany. 4. Department of Radiotherapy and Radiation Oncology, University Medical Center Hamburg Eppendorf, Germany. 5. Department of Otolaryngology and Head and Neck Surgery, University Medical Center Hamburg Eppendorf, Germany; Laboratory of Radiobiology & Experimental Radiation Oncology, University Medical Center Hamburg Eppendorf, Germany. Electronic address: t.rieckmann@uke.uni-hamburg.de.
Abstract
BACKGROUND AND PURPOSE: HPV-positive HNSCC cells are characterized by radiosensitivity, inefficient DNA double-strand break repair and a profound and prolonged arrest in G2. Here we explored the effect of clinically relevant inhibitors of Chk1 and Wee1 to inhibit the radiation-induced G2-arrest in order to achieve further radiosensitization. MATERIAL AND METHODS: Assessment of Chk1 activity by Western blot; assessment of cell cycle distribution by propidium iodide staining and flow cytometry; assessment of cell survival by colony formation assay. HPV+ HNSCC cell lines: UD-SCC-2, UM-SCC-47 and UPCI-SCC-154; Chk1 inhibitors: LY2603618, MK8776; Wee1 inhibitor: AZD1775. RESULTS: Specific Chk1 inhibitors efficiently abrogated the radiation-induced G2-arrest and caused radiosensitization. Wee-inhibition by AZD1775 resulted in the activation of Chk1. This feedback mechanism is likely to counteract some of the effects of Wee1 inhibition but could be antagonized through the combined inhibition of both kinases. Combined inhibition was effective using profoundly reduced concentrations of both inhibitors and resulted in more efficient radiosensitization of the HPV-positive cell lines compared to p53 proficient normal human fibroblasts. CONCLUSIONS: Specific Chk1 inhibitors as well as the combined inhibition of Chk1 and Wee1 radiosensitize HPV-positive HNSCC cells.
BACKGROUND AND PURPOSE: HPV-positive HNSCC cells are characterized by radiosensitivity, inefficient DNA double-strand break repair and a profound and prolonged arrest in G2. Here we explored the effect of clinically relevant inhibitors of Chk1 and Wee1 to inhibit the radiation-induced G2-arrest in order to achieve further radiosensitization. MATERIAL AND METHODS: Assessment of Chk1 activity by Western blot; assessment of cell cycle distribution by propidium iodide staining and flow cytometry; assessment of cell survival by colony formation assay. HPV+ HNSCC cell lines: UD-SCC-2, UM-SCC-47 and UPCI-SCC-154; Chk1 inhibitors: LY2603618, MK8776; Wee1 inhibitor: AZD1775. RESULTS: Specific Chk1 inhibitors efficiently abrogated the radiation-induced G2-arrest and caused radiosensitization. Wee-inhibition by AZD1775 resulted in the activation of Chk1. This feedback mechanism is likely to counteract some of the effects of Wee1 inhibition but could be antagonized through the combined inhibition of both kinases. Combined inhibition was effective using profoundly reduced concentrations of both inhibitors and resulted in more efficient radiosensitization of the HPV-positive cell lines compared to p53 proficient normal human fibroblasts. CONCLUSIONS: Specific Chk1 inhibitors as well as the combined inhibition of Chk1 and Wee1 radiosensitize HPV-positive HNSCC cells.
Authors: Chang Xu; Olga Nikolova; Ryan S Basom; Ryan M Mitchell; Reid Shaw; Russell D Moser; Heuijoon Park; Kay E Gurley; Michael C Kao; Carlos L Green; Franz X Schaub; Robert L Diaz; Hallie A Swan; In S Jang; Justin Guinney; Vijayakrishna K Gadi; Adam A Margolin; Carla Grandori; Christopher J Kemp; Eduardo Méndez Journal: Clin Cancer Res Date: 2018-03-29 Impact factor: 12.531
Authors: Jessica M Molkentine; David P Molkentine; Kathleen A Bridges; Tongxin Xie; Liangpeng Yang; Aakash Sheth; Timothy P Heffernan; David A Clump; Alma Z Faust; Robert L Ferris; Jeffrey N Myers; Mitchell J Frederick; Kathryn A Mason; Raymond E Meyn; Curtis R Pickering; Heath D Skinner Journal: Int J Radiat Biol Date: 2020-02-25 Impact factor: 2.694
Authors: Michael T Spiotto; Cullen M Taniguchi; Ann H Klopp; Lauren E Colbert; Steven H Lin; Li Wang; Mitchell J Frederick; Abdullah A Osman; Curtis R Pickering; Steven J Frank Journal: Semin Radiat Oncol Date: 2021-10 Impact factor: 5.421
Authors: Anne M van Harten; Marijke Buijze; Richard van der Mast; Martin A Rooimans; Sanne R Martens-de Kemp; Costa Bachas; Arjen Brink; Marijke Stigter-van Walsum; Rob M F Wolthuis; Ruud H Brakenhoff Journal: Oncogenesis Date: 2019-06-17 Impact factor: 7.485
Authors: Carmelina Antonella Iannuzzi; Paola Indovina; Iris Maria Forte; Sarah Di Somma; Anna Maria Malfitano; Martina Bruno; Giuseppe Portella; Francesca Pentimalli; Antonio Giordano Journal: Int J Mol Sci Date: 2020-10-04 Impact factor: 5.923