Glaser K, Schepers EJ, Zwolshen HM, Lake CM, Timchenko NA, Karns RA, Cairo S, Geller JI, Tiao GM, Bondoc AJ. EZH2 is a key component of hepatoblastoma tumor cell growth.
Pediatr Blood Cancer 2024;
71:e30774. [PMID:
37990130 PMCID:
PMC10842061 DOI:
10.1002/pbc.30774]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 10/17/2023] [Accepted: 11/06/2023] [Indexed: 11/23/2023]
Abstract
BACKGROUND
Enhancer of zeste homolog 2 (EZH2) catalyzes the trimethylation of histone H3 at lysine 27 via the polycomb recessive complex 2 (PRC2) and plays a time-specific role in normal fetal liver development. EZH2 is overexpressed in hepatoblastoma (HB), an embryonal tumor. EZH2 can also promote tumorigenesis via a noncanonical, PRC2-independent mechanism via proto-oncogenic, direct protein interaction, including β-catenin. We hypothesize that the pathological activation of EZH2 contributes to HB propagation in a PRC2-independent manner.
METHODS AND RESULTS
We demonstrate that EZH2 promotes proliferation in HB tumor-derived cell lines through interaction with β-catenin. Although aberrant EZH2 expression occurs, we determine that both canonical and noncanonical EZH2 signaling occurs based on specific gene-expression patterns and interaction with SUZ12, a PRC2 component, and β-catenin. Silencing and inhibition of EZH2 reduce primary HB cell proliferation.
CONCLUSIONS
EZH2 overexpression promotes HB cell proliferation, with both canonical and noncanonical function detected. However, because EZH2 directly interacts with β-catenin in human tumors and EZH2 overexpression is not equal to SUZ12, it seems that a noncanonical mechanism is contributing to HB pathogenesis. Further mechanistic studies are necessary to elucidate potential pathogenic downstream mechanisms and translational potential of EZH2 inhibitors for the treatment of HB.
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