The selective PI3Kα inhibitor BYL719 as a novel therapeutic option for neuroendocrine tumors: Results from multiple cell line models (pdf)

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The selective PI3Kα inhibitor BYL719 as a novel therapeutic option for neuroendocrine tumors: Results from multiple cell line models

RESEARCH ARTICLE The selective PI3Kα inhibitor BYL719 as a novel therapeutic option for neuroendocrine tumors: Results from multiple cell line models a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Nölting S, Rentsch J, Freitag H, Detjen K, Briest F, Möbs M, et al. (2017) The selective PI3Kα inhibitor BYL719 as a novel therapeutic option for neuroendocrine tumors: Results from multiple cell line models. PLoS ONE 12(8): e0182852. https:// doi.org/10.1371/journal.pone.0182852 Editor: Aamir Ahmad, University of South Alabama Mitchell Cancer Institute, UNITED STATES Svenja Nölting1,2, Jakob Rentsch3, Helma Freitag3, Katharina Detjen3, Franziska Briest3,4,5, Markus Möbs6, Victoria Weissmann7, Britta Siegmund3, Christoph J. Auernhammer1,2, Elke Tatjana Aristizabal Prada1, Michael Lauseker8, Ashley Grossman9, Samantha Exner3, Christian Fischer3, Carsten Grötzinger3, Jörg Schrader7,10☯, Patricia Grabowski3,4☯*, on behalf of the GERMAN NET-Z study group¶ 1 Department of Internal Medicine II, Klinikum der Universität München (KUM), Ludwig-MaximiliansUniversität München, München, Bavaria, Germany, 2 Department of Internal Medicine IV, Klinikum der Universität München (KUM), Ludwig-Maximilians-Universität München, München, Bavaria, Germany, 3 Dept. of Gastroenterology, CC13 (CBF and CVK), Charité - Universitätsmedizin Berlin, Berlin, Germany, 4 Dept. of Gastroenterology and Endocrinology, Zentralklinik Bad Berka GmbH, Bad Berka, Germany, 5 Dept. of Chemistry and Biochemistry, Freie Universität (FU) Berlin, Berlin, Germany, 6 Institute of Pathology, Charité - Universitätsmedizin Berlin, Berlin, Germany, 7 Department of General, Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 8 Institute for Medical Information Sciences, Biometry, and Epidemiology, Ludwig-Maximilians-Universität München, München, Bavaria, Germany, 9 Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, United Kingdom and Neuroendocrine Tumour Centre, Royal Free Hospital, London, United Kingdom, 10 Medical Department I, University Medical Center Hamburg-Eppendorf, Hamburg, Germany ☯ These authors contributed equally to this work. ¶ Complete membership of the author group can be found in the Acknowledgments. * Abstract Received: April 11, 2017 Accepted: July 25, 2017 Background/Aims Published: August 11, 2017 The therapeutic options for metastatic neuroendocrine tumors (NETs) are limited. As PI3K signaling is often activated in NETs, we have assessed the effects of selective PI3Kp110α inhibition by the novel agent BYL719 on cell viability, colony formation, apoptosis, cell cycle, signaling pathways, differentiation and secretion in pancreatic (BON-1, QGP-1) and pulmonary (H727) NET cell lines. Copyright: © 2017 Nölting et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: This work has been supported by a grant from NOVARTIS (YING Investigator program) to JS and from the Roggenbruck Foundation (Hamburg, Germany) to JS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. "Zentralklinik Bad Berka GmbH, Germany" is a communal hospital of the Rhön- Methods Cell viability was investigated by WST-1 assay, colony formation by clonogenic assay, apoptosis by caspase3/7 assay, the cell cycle by FACS, cell signaling by Western blot analysis, expression of chromogranin A and somatostatin receptors 1/2/5 by RT-qPCR, and chromogranin A secretion by ELISA. Results BYL719 dose-dependently decreased cell viability and colony formation with the highest sensitivity in BON-1, followed by H727, and lowest sensitivity in QGP-1 cells. BYL719 PLOS ONE | https://doi.org/10.1371/journal.pone.0182852 August 11, 2017 1 / 29 PI3Kα inhibition in neuroendocrine tumor cells Klinikum AG and provided support in the form of salaries for authors [FB,PG], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the author contributions section. Competing interests: CJA has received research contracts (Ipsen, Novartis), lecture honoraria (Ipsen, Novartis, Pfizer, Amgen, Roche, Falk) and advisory board honoraria (Novartis). JS has received travel assistance, speakers honoraria and research funding from Novartis and travel assistance and speakers honoraria from Ipsen. PG has received research contracts (Ipsen, Novartis) and lecture honoraria (Ipsen, Novartis). SN has received travel assistance, speakers honoraria and research funding from Novartis and travel assistance and speakers honoraria from Ipsen. ABG has received lecture fees and advisory board honoraria from Novartis. The authors declare that there is no conflict of interest that would prejudice the impartiality of this scientific work. This does not alter the authors’ adherence to PLOS ONE policies on sharing data and materials. "Zentralklinik Bad Berka GmbH, Germany" is a communal hospital of the Rhön-Klinikum AG and provided support in the form of salaries for authors [FB,PG]. This does not alter the authors’ adherence to PLOS ONE policies on sharing data and materials. induced apoptosis and G0/G1 cell cycle arrest associated with increased p27 expression. Western blots showed inhibition of PI3K downstream targets to a varying degree in the different cell lines, but IGF1R activation. The most sensitive BON-1 cells displayed a significant, and H727 cells a non-significant, GSK3 inhibition after BYL719 treatment, but these effects do not appear to be mediated through the IGF1R. In contrast, the most resistant QGP-1 cells showed no GSK3 inhibition, but a modest activation, which would partially counteract the other anti-proliferative effects. Accordingly, BYL719 enhanced neuroendocrine differentiation with the strongest effect in BON-1, followed by H727 cells indicated by induction of chromogranin A and somatostatin receptor 1/2 mRNA-synthesis, but not in QGP-1 cells. In BON-1 and QGP-1 cells, the BYL719/everolimus combination was synergistic through simultaneous AKT/mTORC1 inhibition, and significantly increased somatostatin receptor 2 transcription compared to each drug separately. Conclusion Our results suggest that the agent BYL719 could be a novel therapeutic approach to the treatment of NETs that may sensitize NET cells to somatostatin analogs, and that if there is resistance to its action this may be overcome by combination with everolimus. Introduction Neuroendocrine tumors (NET) are a heterogeneous group of malignancies. (...truncated)