1. Combined inhibition of EZH2 and CDK4/6 perturbs endoplasmic reticulum-mitochondrial homeostasis and increases antitumor activity against glioblastoma
- Author
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Thomas Freitag, Philipp Kaps, Justus Ramtke, Sarah Bertels, Emily Zunke, Björn Schneider, Anne-Sophie Becker, Dirk Koczan, Daniel Dubinski, Thomas M. Freiman, Felix Wittig, Burkhard Hinz, Mike-Andrew Westhoff, Hannah Strobel, Franziska Meiners, Daniel Wolter, Nadja Engel, Sascha Troschke-Meurer, Wendy Bergmann-Ewert, Susanne Staehlke, Annabell Wolff, Florian Gessler, Christian Junghanss, and Claudia Maletzki
- Subjects
Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract Here, we show that combined use of the EZH2 inhibitor GSK126 and the CDK4/6 inhibitor abemaciclib synergistically enhances antitumoral effects in preclinical GBM models. Dual blockade led to HIF1α upregulation and CalR translocation, accompanied by massive impairment of mitochondrial function. Basal oxygen consumption rate, ATP synthesis, and maximal mitochondrial respiration decreased, confirming disrupted endoplasmic reticulum-mitochondrial homeostasis. This was paralleled by mitochondrial depolarization and upregulation of the UPR sensors PERK, ATF6α, and IRE1α. Notably, dual EZH2/CDK4/6 blockade also reduced 3D-spheroid invasion, partially inhibited tumor growth in ovo, and led to impaired viability of patient-derived organoids. Mechanistically, this was due to transcriptional changes in genes involved in mitotic aberrations/spindle assembly (Rb, PLK1, RRM2, PRC1, CENPF, TPX2), histone modification (HIST1H1B, HIST1H3G), DNA damage/replication stress events (TOP2A, ATF4), immuno-oncology (DEPDC1), EMT-counterregulation (PCDH1) and a shift in the stemness profile towards a more differentiated state. We propose a dual EZH2/CDK4/6 blockade for further investigation.
- Published
- 2024
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