EP31670

P1, N=75, Recruiting, Epigenetix, Inc. | N=50 --> 75 | Trial completion date: Sep 2024 --> May 2025 | Trial primary completion date: Jun 2024 --> May 2025

A combined inhibitor of these three proteins, NEO2734, reduced the growth of both AR-positive and AR-null organoids, as measured by changes in viability, size, and composition..

We demonstrated effectiveness and reliability of this pipeline through validation of the established finding that the first-in-class BET and CBP/p300 dual inhibitor EP-31670 is an effective compound in reducing ADPC and CRPC cell growth. In addition, we found that insulin-like growth factor-1 receptor (IGF-1R) inhibitor linsitinib is a potential pharmacological agent against highly lethal and drug-resistant NEPC NCI-H660 cells. This protocol can be employed across other cancer types and represents an adaptable strategy to optimize assay-specific cell growth conditions and simultaneously assess drug efficacy across multiple cell lines.

Here we demonstrated that acute treatment with the antiandrogen enzalutamide (ENZ) decreased glutathione (GSH) production, increased lipid peroxidation, and induced ferroptosis in prostate cancer cells...However, this effect was abolished following downregulation of AR-Vs using the dual CBP/p300 and BET inhibitor NEO2734...These findings reveal ferroptosis induction as an anti-cancer mechanism of antiandrogens and SLC7A11 as a direct target gene of AR-FL and AR-Vs. AR-V-mediated SLC7A11 expression represents a mechanism coupling ferroptosis resistance to PCa progression.

BCa organoids responded to doxorubicin, EP31670 and paclitaxel treatments with increased IC concentrations on organoids compared to 2D cultures, and highest IC for organoids in GelSH. Cell viability after doxorubicin treatment (1 µM) remained >2-fold higher in the 3D gels compared to 2D and doxorubicin/paclitaxel (both 5 µM) were ~2.75-3-fold less potent in GelSH compared to PEG hydrogels. The data demonstrate the potential of hydrogel matrices as easy-to-use and effective preclinical tools for therapy assessment in patient-derived breast cancer organoids.

Our study demonstrates NEO2734 potently suppresses CRC cells in vitro and in vivo by simultaneously upregulating PUMA and DR5 to induce cell death. Further studies of NEO2734 for treating CRC are warranted.

Our biochemical and structural analyses further showed that NEO2734, a dual-inhibitor targeting BRD4 and p300 bromodomains exhibits greater efficacy than single inhibitors for BRD4 or CBP/p300 in suppressing CDCP1 transcriptional expression and its downstream signaling pathways in CRPC cell proliferation and metastasis. Our study illustrates that targeting CDCP1 through dual-inhibition of BRD4 and CBP/p300 represents a synergistic therapeutic strategy for new treatment of CRPC.

Resistance to next-generation anti-androgen enzalutamide (ENZ) constitutes a major challenge for the treatment of castration-resistant prostate cancer (CRPC). Consistent with the finding that ARBS-gained loci are highly enriched with H3K27ac modification, ENZ-resistant PCa cells, organoids, xenografts and PDXs are hyper-sensitive to NEO2734, a dual inhibitor of BET and CBP/p300 proteins. These results not only reveal a noncanonical AR function in acquisition of ENZ resistance, but also posit a treatment strategy to target this vulnerability in ENZ-resistant CRPC.

HDAC5 loss also conferred resistance to CDK4/6 inhibitors such as Palbociclib in prostate and breast cancer cells in vitro and prostate tumors in vivo, but this effect was overcome by the BET-CBP/p300 dual inhibitor NEO2734. Our findings reveal an unknown role of HDAC5 in RB-mediated histone deacetylation and gene repression and define a new mechanism modulating CDK4/6 inhibitor therapeutic sensitivity in cancer cells.

The dual inhibition of BET and CBP/EP300 has potential therapeutic benefits for patients with MM.

However, NEO2734 was more potent than single-agent BET or CBP/EP300 inhibitors alone. In conclusion, NEO2734 is a novel antitumor compound that shows preferential activity in lymphomas, leukemias, and prostate cancers.