Abstract 4386: Androgen hormone signaling regulates the association between the hippo pathway component YAP1 and RNA binding protein NPM1

Abstract

Abstract Prostate cancer represents a major health concern for men in the United States and globally, disproportionately affecting men of African descent. Despite recent advances, the precise etiology and molecular mechanisms underpinning fatal prostate cancer in humans remain inadequately understood. RNA binding proteins (RBPs) regulate various aspects of RNA biology, and when their regulation is disrupted, they can lead to human diseases, including cancer. However, the comprehensive alterations in RBP-mRNA interactions in prostate cancer have not been explored. In this study, we investigated the dynamics of RBPs and their interactions with polyadenylated mRNA in the castration-sensitive LNCaP and castration-resistant C4-2 prostate cancer cell lines. Using an enhanced RNA interactome capture assay in combination with mass spectrometry, we discovered that LNCaP and C4-2 cells showed distinct RBP-mRNA interaction patterns in steady-state growth conditions and in response to androgen treatment. Additionally, we investigated the interplay between the oncogene Yes-associated protein 1 (YAP1) and the RNA-binding protein nucleophosmin (NPM1). We identified NPM1 as a component of the YAP1 protein complex through mass spectrometry-based proteomics. Our proximity ligation assay demonstrated that androgen signaling could regulate the interaction between YAP1 and NPM1. Also, our GST-pulldown revealed that NPM1 binds to the proline-rich domain of YAP1 in LNCaP cells, while the WW/SH3 domain of YAP1 mediates the interaction with NPM1 in C4-2 cells. Genetic and pharmacological inhibition of NPM1 activity reduced prostate cancer cell growth in culture by modulating cell cycle progression. Furthermore, our computational and immunological analysis of prostate tumor tissues indicated that the upregulation of NPM1 might be associated with the clinical advancement of human prostate cancer. These findings underscore the critical role of the molecular functional connection between YAP1 and RBPs and the global changes in RBP and RNA interaction patterns, in the progression and recurrence of prostate cancer. Citation Format: Abdulrahman M. Dwead, Marwah M. Al-Mathkour, Bekir Cinar. Androgen hormone signaling regulates the association between the hippo pathway component YAP1 and RNA binding protein NPM1 [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 4386.