1. MerTK activity is not necessary for the proliferation of glioblastoma stem cells.
- Author
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Hoque M, Wai Wong S, Recasens A, Abbassi R, Nguyen N, Zhang D, Stashko MA, Wang X, Frye S, Day BW, Baell J, and Munoz L
- Subjects
- Animals, Cell Line, Tumor, Cell Proliferation drug effects, Cyclohexanols pharmacology, Dose-Response Relationship, Drug, Glioblastoma pathology, Humans, Mice, Mice, Inbred NOD, Mice, SCID, Neoplastic Stem Cells drug effects, Neoplastic Stem Cells pathology, Protein Kinase Inhibitors pharmacology, Pyrimidines pharmacology, Xenograft Model Antitumor Assays methods, Cell Proliferation physiology, Glioblastoma enzymology, Neoplastic Stem Cells enzymology, c-Mer Tyrosine Kinase antagonists & inhibitors, c-Mer Tyrosine Kinase biosynthesis
- Abstract
MerTK has been identified as a promising target for therapeutic intervention in glioblastoma. Genetic studies documented a range of oncogenic processes that MerTK targeting could influence, however robust pharmacological validation has been missing. The aim of this study was to assess therapeutic potential of MerTK inhibitors in glioblastoma therapy. Unlike previous studies, our work provides several lines of evidence that MerTK activity is dispensable for glioblastoma growth. We observed heterogeneous responses to MerTK inhibitors that could not be correlated to MerTK inhibition or MerTK expression in cells. The more selective MerTK inhibitors UNC2250 and UNC2580A lack the anti-proliferative potency of less-selective inhibitors exemplified by UNC2025. Functional assays in MerTK-high and MerTK-deficient cells further demonstrate that the anti-cancer efficacy of UNC2025 is MerTK-independent. However, despite its efficacy in vitro, UNC2025 failed to attenuate glioblastoma growth in vivo. Gene expression analysis from cohorts of glioblastoma patients identified that MerTK expression correlates negatively with proliferation and positively with quiescence genes, suggesting that MerTK regulates dormancy rather than proliferation in glioblastoma. In summary, this study demonstrates the importance of orthogonal inhibitors and disease-relevant models in target validation studies and raises a possibility that MerTK inhibitors could be used to target dormant glioblastoma cells., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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