Gangadhara R. Sareddy

Pharmacological inhibition of KDM1A/LSD1 enhances estrogen receptor beta-mediated tumor suppression in ovarian cancer

Ovarian cancer (OCa) is the most lethal gynecologic cancer. Emerging data indicates that estrogen receptor beta (ERβ) functions as a tumor suppressor in OCa. Lysine-specific histone demethylase 1A (KDM1A) is an epigenetic modifier that acts as a coregulator for steroid hormone receptors. However, it remain unknown if KDM1A interacts with ERβ and regulates its expression/functions in OCa. Analysis of TCGA data sets indicated KDM1A and ERβ expression showed an inverse relationship in OCa. Knockout (KO), knockdown (KD), or inhibition of KDM1A increased ERβ isoform 1 expression in established and patient-derived OCa cells. Further, KDM1A interacts with and functions as a corepressor of ERβ, and its inhibition enhances ERβ target gene expression via alterations of histone methylation marks at their promoters. Importantly, KDM1A-KO or -KD enhanced the efficacy of ERβ agonist LY500307, and the combination of KDM1A inhibitor (KDM1Ai) NCD38 with ERβ agonist synergistically reduced the cell viability, colony formation, and invasion of OCa cells. RNA-seq and DIA mass spectrometry analyses showed that KDM1A-KO resulted in enhanced ERβ signaling and that genes altered by KDM1A-KO and ERβ agonist were related to apoptosis, cell cycle, and EMT. Moreover, combination treatment significantly reduced the tumor growth in OCa orthotopic, syngeneic, and patient-derived xenograft models and proliferation in patient-derived explant models. Our results demonstrate that KDM1A regulates ERβ expression/functions, and its inhibition improves ERβ mediated tumor suppression. Overall, our findings suggest that KDM1Ai and ERβ agonist combination therapy is a promising strategy for OCa.

Therapeutic optimization of LIPA targeting to induce endoplasmic reticulum stress and cell death in ovarian cancer

Ovarian cancer (OCa) remains the most lethal gynecologic malignancy in the United States, with a five-year survival rate below 20%. Elevated basal levels of endoplasmic reticulum stress (ERS) have recently emerged as a therapeutic vulnerability in OCa. We have previously shown that the tris-benzamide ERX-41 can induce ERS and cancer cell death in OCa by targeting LIPA. In this study, using iterative structure-activity relationship-guided studies to enhance activity in OCa, we identified a more potent ERX-41-derived analog, ERX-208. Importantly, ERX-208 consistently and significantly reduced cell viability in 23 OCa cell lines spanning five major histological OCa subtypes, with IC₅₀ values ranging from 50-100 nM, compared to ∼500 nM for ERX-41. Notably, ERX-208 showed minimal cytotoxicity toward normal ovarian surface epithelial cells, indicating cancer cell selectivity. ERX-208 induced apoptosis and suppressed colony formation in vitro in OCa cells. Mechanistic studies using RNA sequencing, Western blotting, RT-qPCR, transmission electron microscopy, and immunohistochemistry validated robust activation of ERS pathways upon ERX-208 treatment. Through in silico molecular docking simulation and confirmatory detailed site-directed mutagenesis, we identified that ERX-208 binds to LIPA over a broader interaction surface than ERX-41. At the 10 mg/kg dose, ERX-208 demonstrated favorable biodistribution, no observable toxicity, and potent antitumor efficacy in vivo against established cell line-derived xenograft (CDX), patient-derived xenograft (PDX), and patient-derived explant (PDE) models. Immunohistochemical analysis of treated tumors demonstrated changes in expression of proliferative marker (ki67, decreased) and the ERS marker (GRP78, increased). These findings support the clinical advancement of ERX-208 for the treatment of patients with OCa.