Abstract
EZH2 (Enhancer of Zeste Homolog 2), a subunit of Poly- comb Repressive Complex 2 (PRC2), catalyzes the trimethyla- tion of histone H3 at lysine 27 (H3K27me3), which represses expression of genes. It also has PRC2-independent functions, including transcriptional coactivation of oncogenes, and is frequently overexpressed in lung cancers. Clinically, EZH2 in- hibition can be achieved with the FDA-approved drug EPZ- 6438 (tazemetostat). To realize the full potential of EZH2 blockade, it is critical to understand how cell-cell/cell-matrix interactions present in 3D tissue and cell culture systems in- fluences this blockade in terms of growth-related metabolic functions. Here, we show that EZH2 suppression reduced growth of human lung adenocarcinoma A549 cells in 2D cul- tures but stimulated growth in 3D cultures. To understand the metabolic underpinnings, we employed [ 13 C6 ]-glucose stable isotope-resolved metabolomics to determine the effect of EZH2 suppression on metabolic networks in 2D versus 3D A549 cultures. The Krebs cycle, neoribogenesis, γ-aminobutyrate metabolism, and salvage synthesis of purine nucleotides were activated by EZH2 suppression in 3D spheroids but not in 2D cells, consistent with the growth effect. Using simultaneous 2 H 7 -glucose + 13 C5 , 15 N 2-Gln tracers and EPZ-6438 inhibition of H3 trimethylation, we delineated the effects on the Krebs cycle, γ-aminobutyrate metabolism, gluconeogenesis, and pu- rine salvage to be PRC2-dependent. Furthermore, the growth/ metabolic effects differed for mouse Matrigel versus self- produced A549 extracellular matrix. Thus, our findings high- light the importance of the presence and nature of extracellular matrix in studying the function of EZH2 and its inhibitors in cancer cells for modeling the in vivo outcomes.
Document Type
Article
Publication Date
2023
Digital Object Identifier (DOI)
https://doi.org/10.1016/j.jbc.2023.105485
Funding Information
Financial supports came from two endowment funds (to T. W.-M. F. and A. N. L.), National Institute of Health (5P20GM121327 pilot to T. W.-M. F.; P30CA177558 to BME; R01CA237643 to C. F. B.), and American Cancer Society (133123-RSG-19-081-01-TBG to C. F. B.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Repository Citation
Fan, Teresa W-M; Islam, Jahid M. M.; Higashi, Richard M.; Lin, Penghui; Brainson, Christine F.; and Lane, Andrew N., "Metabolic reprogramming driven by EZH2 inhibition depends on cell–matrix interactions" (2023). Markey Cancer Center Faculty Publications. 253.
https://uknowledge.uky.edu/markey_facpub/253
Notes/Citation Information
© 2023 THE AUTHORS. Published by Elsevier Inc on behalf of American Society for Biochemistry and Molecular Biology. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).