Albacarcin V adds EPLIN as a novel and promising target for the treatment of female cancers and pediatric medulloblastoma.

Breast and ovarian cancers remain among the most lethal malignancies affecting women worldwide. Despite advances in standard therapies, drug resistance and high relapse rates continue to undermine long-term treatment outcomes. To address these challenges, we re-evaluated five previously identified drug candidates (FLIX1-FLIX5), all of which are effective at nanomolar concentrations in breast and ovarian cancer cell lines. Among them, FLIX3 (Albacarcin V) and FLIX4 exhibited the most potent cytotoxicity, with IC50 values below 50 nM across multiple cell lines. Notably, FLIX3 also exhibited nanomolar-range efficacy in drug-resistant, patient-derived samples from triple-negative breast cancer (TNBC) and ovarian cancer. In a zebrafish model, FLIX3 effectively eliminated cancer cells within its safety window. ATAC-Seq analysis revealed that both compounds induce significant epigenetic alterations. Proteome Integral Solubility Alteration (PISA) and cellular thermal shift assay (CETSA) identified EPLIN (Epithelial Protein Lost in Neoplasm) as the top target of FLIX3 but not FLIX4. EPLIN was previously identified as the primary target of FLIX5. Its re-emergence as the dominant target of FLIX3 highlights its potential as a broadly applicable therapeutic target. Collectively, these findings support the continued development of EPLIN-targeting compounds as promising agents for treating aggressive and drug-resistant breast and ovarian cancers.