Combined Targeting of the BRD4–NUT–p300 Axis in NUT Midline Carcinoma by Dual Selective Bromodomain Inhibitor, NEO2734

Abstract

NUT midline carcinoma (NMC) is a rare, aggressive subtype of squamous carcinoma that is driven by the BRD4-NUT fusion oncoprotein. BRD4, a BET protein, binds to chromatin through its two bromodomains, and NUT recruits the p300 histone acetyltransferse (HAT) to activate transcription of oncogenic target genes. BET-selective bromodomain inhibitors have demonstrated on-target activity in patients with NMC, but with limited efficacy. P300, like BRD4, contains a bromodomain. We show that combining selective p300/CBP and BET bromodomain inhibitors, GNE-781 and OTX015, respectively, induces cooperative depletion of MYC and synergistic inhibition of NMC growth. Treatment of NMC cells with the novel dual p300/CBP and BET bromodomain-selective inhibitor, NEO2734, potently inhibits growth and induces differentiation of NMC cells in vitro; findings that correspond with potentiated transcriptional effects from combined BET and p300 bromodomain inhibition. In three disseminated NMC xenograft models, NEO2734 provided greater growth inhibition, with tumor regression and significant survival benefit seen in two of three models, compared with a lead clinical BET inhibitor or "standard" chemotherapy. Our findings provide a strong rationale for clinical study of NEO2734 in patients with NMC. Moreover, the synergistic inhibition of NMC growth by CBP/p300 and BET bromodomain inhibition lays the groundwork for greater mechanistic understanding of the interplay between p300 and BRD4-NUT that drives this cancer.

Targeting both BET and CBP/EP300 proteins with the novel dual inhibitors NEO2734 and NEO1132 leads to anti‐tumor activity in multiple myeloma

“…These data indicate that NEO2734 and NEO1132 would be good candidates for combinational drug studies in MM and maybe potentially beneficial in reducing resistance in MM and restoring sensitivity to immunomodulatory drugs in relapse/refractory MM patients. NEO2734, unlike JQ1, has been shown to be tolerated well in preclinical animal models 37‐41 . Taken together, these data indicate the potential value of the novel dual inhibitors, NEO2734 and NEO1132, as a single‐drug double‐hit approach for treating a broad range of MM and warrant further clinical investigation.…”

“…Due to these issues several JQ1 derivatives have been developed for clinical applications, among them are OTX015 and I‐BET762, which we also included in our study, these have been shown to be tolerated well in early phase clinical trials as therapies for hematologic malignancies including MM (see ClinicalTrials.gov). Unlike JQ1, NEO2734 is tolerated well in mice indicating, although highly potent, NEO2734 has the potential to be taken forward into clinical trials 37,40,41 …”

A noncanonical AR addiction drives enzalutamide resistance in prostate cancer

“…Through unbiased signaling pathway inhibitor survey, we demonstrate that ENZ-R cells are hyper-sensitive to the dual inhibitors of BET and CBP/p300 proteins such as NEO2734 [50][51][52] . In agreement with these results, we show that chromatin occupancy of CXXC5 and H3K27ac levels are positively correlated at noncanonical AR target loci and that the BET-CBP/p300 dual inhibitor treatment inhibits CXXC5 protein expression and decreases BRD4 and p300 binding and H3K27ac levels at these loci.…”

SETD2 and miR-21 as therapeutic targets for NUT midline carcinoma

“…We found that the combination of the BET inhibitor and WEE1 inhibitor had additive effects on NMC. Moreover, a recent report showed that the combination therapy targeting BET and p300, which belongs to writers and acetylates histone lysine residues, was more effective than BET inhibitor alone [42]. Given the epigenetic categories in histone modi cation, the combination of BET inhibitors and target inhibitors in another epigenetic category might be useful for the treatment of NMC.…”