The Novel Hypomethylating Agent NTX-301 Reprograms Epigenetic and Hippo Signaling Pathways and Exhibits Preclinical Activity in Venetoclax-Resistant and TP53-Mutant AML.

PURPOSE: Hypomethylating agent (HMA) and the BCL-2 inhibitor venetoclax (VEN) combinations have evolved into first-line therapies for patients with acute myeloid leukemia (AML), yielding high response rates. However, most patients ultimately relapse, particularly those with TP53 mutations. We investigated mechanisms of action and therapeutic efficacy of NTX-301, a next-generation HMA.

EXPERIMENTAL

DESIGN

Methods used include flow cytometry-based cell viability assays, Western blotting, reverse-phase protein arrays, RNA sequencing, Cytometry by Time-Of-Flight single-cell mass cytometry, and methylation profiling in various therapy-resistant AML models.

RESULTS

We demonstrate that NTX-301 exhibits superior efficacy compared with 5-azacytidine (5-AZA) in 5-AZA- or VEN-resistant AML. It synergizes with VEN in VEN- or VEN/HMA-resistant and TP53-mutant AML blasts and stem/progenitor cells (combination index <1). NTX-301 inhibits DNA methyltransferase 1 (DNMT1) and increases p73 and caspase 8 (CASP8)/activated CASP8 levels in TP53 wild-type and TP53-mutant AML and activates p53 signaling. It extends survival (≥45%) in both xenograft and patient-derived xenograft models. Methylation profiling revealed that NTX-301 is a more targeted HMA compared with 5-AZA, enabling suppression of functionally enriched genes/pathways. Pathway analysis of 954 commonly hypomethylated genes showed profoundly greater enrichment of Hippo signaling in NTX-301-treated compared with 5-AZA-treated cells and enrichment of insulin signaling, VEGF pathway, and cell cycle selectively in NTX-301- but not in 5-AZA-treated cells. NTX-301-mediated Hippo signaling was validated at protein levels.

CONCLUSIONS

Data suggest that NTX-301 exerts potent antileukemic activities superior to 5-AZA and synergizes with VEN in VEN-resistant and TP53-mutant AML, in part by suppressing DNMT1, inducing DNA damage responses and apoptosis through p53 signaling, and demethylating LATS1/2, thereby activating Hippo signaling.