Abstract 2011: MAOA Drives Anti Androgen Therapy Resistance in Advanced Prostate Cancer by Conferring Neuroendocrine Plasticity via a Twist1 BRN2 Signaling Pathway
Authors: Wei Jing , Wang Jing , Chen Chia-hui , Guan Wen , Wu Boyang 
Published: March 2024

Abstract
Background: Therapy resistance in cancer is often linked to cancer cell state or lineage changes. In prostate cancer (PCa), a subset of castration-resistant prostate cancer (CRPC) loses reliance on the androgen receptor (AR) signaling and gains neuroendocrine (NE) traits through a lineage switch along disease progression. However, the molecular mechanisms driving such cellular lineage plasticity remain unclear. This study investigated the functional and mechanistic role of monoamine oxidase A (MAOA) in driving adenocarcinoma (adeno)-to-NE lineage conversion in CRPC cells upon enzalutamide (ENZ), a FDA-approved newer-generation antiandrogen drug, and evaluated the efficacy of MAOA inhibitors for treating CRPC and overcoming ENZ resistance.Methods: ENZ-resistant C4-2B and CWR-R1 cells (C4-2BENZR and CWR-R1ENZR) CRPC cells were transfected with a PSA promoter-driven GFP expression construct for isolating a PSAlo/− cell population distinct from PSAhi cells, which was used for manipulation of MAOA expression levels and subsequent functional assays in vitro and in vivo. The MAOA expression levels were determined and correlated with NE parameters in PCa clinical samples by immunohistochemistry and data mining of multiple publicly available clinical datasets. Results: MAOA protein expression was significantly upregulated in the PSAlo/− ENZ-resistant cell population, accompanied by concomitant activation of NE markers and downregulation of luminal markers including AR and AR targets, compared to the PSAhi counterpart. Elevated MAOA expression was also found in PCa patient samples associated with NE features from multiple independent cohorts. Silencing MAOA suppressed the proliferation, migration, invasion, stem-like properties and NE plasticity of both PSAlo/- C4-2BENZR and CWR-R1ENZR cells. Moreover, co-culturing adeno LNCaP or C4-2B cells with MAOA-silenced PSAlo/- cells exhibiting a repressed secretory phenotype attenuated acquired induction of NE markers and proliferation of adeno cells as compared to controls. Mechanistically, MAOA induces Twist1, which directly activates the transcription and expression of BRN2, a master neural transcription factor known to confer NE differentiation and anti-AR therapy resistance in CRPC. Further, pharmacological inhibition of MAOA greatly enhanced the growth-inhibitory efficacy of ENZ with ENZ sensitivity restored in ENZ-resistant LuCaP PC PDX-derived organoids as well as a PSAlo/− CWR-R1ENZR xenograft mouse model.Conclusion: Our results suggest MAOA as a potential therapeutic target for reversing ENZ resistance in CRPC treatment by blockade of NE transdifferentiation.Funding Acknowledgements: This work was supported by the NIH/NCI grants R37CA233658 and R01CA258634 (to B. Wu) and the DOD Department of Defense EIRA award W81XWH-21-1-0218 (to J. Wei)
Citation Format: Jing Wei, Jing Wang, Chia-hui Chen, Wen Guan, Boyang Wu. MAOA Drives Anti Androgen Therapy Resistance in Advanced Prostate Cancer by Conferring Neuroendocrine Plasticity via a Twist1 BRN2 Signaling Pathway [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 2011.