Glutaminase inhibition with telaglenastat (CB-839) improves treatment response in combination with ionizing radiation in head and neck squamous cell carcinoma models

Christina A. Wicker, Brian G. Hunt, Sunil Krishnan, Kathryn Aziz, Shobha Parajuli, Sarah Palackdharry, William R. Elaban, Trisha M. Wise-Draper, Gordon B. Mills, Susan E. Waltz, Vinita Takiar

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The efficacy of ionizing radiation (IR) for head and neck cancer squamous cell carcinoma (HNSCC) is limited by poorly understood mechanisms of adaptive radioresistance. Elevated glutaminase gene expression is linked to significantly reduced survival (p < 0.03). The glutaminase inhibitor, telaglenastat (CB-839), has been tested in Phase I/II cancer trials and is well tolerated by patients. This study investigated if telaglenastat enhances the cellular response to IR in HNSCC models. Using three human HNSCC cell lines and two xenograft mouse models, we examined telaglenastat's effects on radiation sensitivity. IR and telaglenastat combinatorial treatment reduced cell survival (p ≤ 0.05), spheroid size (p ≤ 0.0001) and tumor growth in CAL-27 xenograft bearing mice relative to vehicle (p ≤ 0.01), telaglenastat (p ≤ 0.05) or IR (p ≤ 0.01) monotherapy. Telaglenastat significantly reduced the Oxygen Consumption Rate/Extracellular Acidification Rate ratio in CAL-27 and HN5 cells in the presence of glucose and glutamine (p ≤ 0.0001). Telaglenastat increased oxidative stress and DNA damage in irradiated CAL-27 cells. These data suggest that combination treatment with IR and telaglenastat leads to an enhanced anti-tumor response. This pre-clinical data, combined with the established safety of telaglenastat justifies further investigation for the combination in HNSCC patients.

    Original languageEnglish (US)
    Pages (from-to)180-188
    Number of pages9
    JournalCancer Letters
    Volume502
    DOIs
    StatePublished - Apr 1 2021

    Keywords

    • Combinatorial therapy
    • Preclinical models
    • Radioresistance
    • Radiosensitivity
    • Small molecule inhibitor

    ASJC Scopus subject areas

    • Oncology
    • Cancer Research

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