Mechanistic basis and efficacy of targeting Beta Catenin-TCF7L2-JMJD6-MYC Axis to overcome resistance to BET inhibitors [OTX015]

ABSTRACT: Promising activity of BET protein inhibitors (BETis) is compromised by adaptive or innate resistance in AML. Here, modeling of BETi- persister/resistance (BETi-P/R) in human post-MPN secondary AML (sAML) cells demonstrated accessible and active chromatin in specific super-enhancers/enhancers, which was associated with increased levels of nuclear β-catenin, TCF7L2, JMJD6, and c-Myc in BETi-P/R sAML cells. Following BETi treatment, c-Myc levels were rapidly restored in BETi-P/R sAML cells. CRISPR/Cas9-mediated knockout of TCF7L2 or JMJD6 reversed BETi-P/R, whereas ectopic overexpression conferred BETi-P/R in sAML cells; confirming the mechanistic role of the β-catenin-TCF7L2- JMJD6-MYC axis in BETi-resistance. Patient-derived, post-MPN, CD34+ sAML blasts exhibiting relative resistance to BETi, as compared to sensitive sAML blasts, displayed higher mRNA and protein expressions of TCF7L2, JMJD6 and c-Myc, and following BETi washout exhibited rapid restoration of c-Myc and JMJD6. CRISPR/Cas9 knockout of TCF7L2 and JMJD6 depleted their levels, inducing loss of viability of the sAML blasts. Disruption of co-localization of nuclear β-catenin with TBL1 and TCF7L2 by the small molecule inhibitor BC2059 combined with depletion of BRD4 by BET-PROTAC reduced c-Myc levels and exerted synergistic lethality in BETi-P/R sAML cells. This combination also reduced leukemia burden and improved survival of mice engrafted with BETi-P/R sAML cells or with patient-derived AML blasts innately resistant to BETi. Therefore, multi- targeted disruption of β-catenin-TCF7L2-JMJD6-MYC axis overcomes adaptive and innate BETi-resistance, exhibiting pre-clinical efficacy against human post-MPN sAML cells.

ORGANISM(S): Homo sapiens

PROVIDER: GSE145274 | GEO | 2020/11/06

REPOSITORIES: GEO