Abstract 7097: Integrated proteomics and metabolomics reveals new insight into the synergistic interaction of valproic acid plus simvastatin in prostate cancer xenograft model associated with down-modulation of YAP and TAZ signaling

Abstract Background: Despite advancements in therapeutic approaches, including taxane-based chemotherapy and androgen receptor targeting agents, metastatic castration-resistant prostate cancer (mCRPC) remains an incurable disease, underlying the need of novel strategies that can target the complexities of this disease and bypass the development of drug-resistance mechanisms. We previously demonstrated the synergistic antitumor interaction of the antiepileptic with histone deacetylase inhibitory activity valproic acid (VPA), and the lipid-lowering drug simvastatin (SIM). This combination sensitizes mCRPC cells to docetaxel treatment and revert docetaxel-resistance, both in vitro and in vivo models, by targeting cancer stem cells compartment via mevalonate pathway/YAP axis modulation. Methods: Proteomic and metabolomic/lipidomic analysis on tumor samples were performed by LC-MS/MS-based shotgun proteomics and by 1H-NMR approach, respectively. Progenesis QI for proteomics v. 4.2 was used as label-free quantification platform. Functional annotation analysis were performed by using the DAVID v6.8 (Database for Annotation, Visualization and Integrated Discovery); g:Profiler WikiPathways databases; Reactome version 66; Ingenuity Pathway Analysis software. Partial least squares-discriminant analysis (PLS-DA) and Loading plot were performed by Metabo Analyst v5.0 tool. Results: Tumor samples derived from 22Rv1 mCRPC cells xenografted mice, treated or not with VPA/SIM combination were characterized by a combined proteomic and metabolomic/lipidomic approach. In deep bioinformatics analysis confirmed a specific impact of VPA/SIM on Hippo pathway, with a clear down regulation of YAP and its targets (CTGF, CycD1 ANKH1) in treated vs untreated tumors, functionally related with modulation of cancer-related extracellular matrix remodelling and metabolic reprogramming. Treatment also downregulated TEAD transcription factor mediating YAP-induced expression, along with the upregulation of 14-3-3, responsible for YAP cytoplasmic retention and degradation, paralleled by the up-regulation of YAP up-stream negative regulators such as LATS1 and AMPK. VPA/SIM also modulated intermediates of TCA, urea cycles and glycolysis and decreased cholesterol and fatty acids. Conclusion: In summary, this study provides further insights into the molecular mechanism of the VPA/SIM antitumor effect suggesting the potential of repurposing these two generic and safe drugs in combination with standard antitumor therapies also in other tumors besides mCRCP. Citation Format: Federica Iannelli, Rita Lombardi, Susan Costantini, Maria Serena Roca, Laura Addi, Francesca Bruzzese, Elena Di Gennaro, Alfredo Budillon, Biagio Pucci. Integrated proteomics and metabolomics reveals new insight into the synergistic interaction of valproic acid plus simvastatin in prostate cancer xenograft model associated with down-modulation of YAP and TAZ signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7097.