Targeting ROS metabolism and hypoxia signaling sensitizes castration-resistant prostate cancer to androgen receptor signaling inhibition
[eng] Most prostate cancer (PCa) patients who undergo Androgen Deprivation Therapy (ADT) exhibit clinical progression, resulting in the development of castration-resistant prostate cancer (CRPC), which is highly metastatic and frequently lethal. The androgen receptor (AR) is expressed at high levels...
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| Format: | doctoral thesis |
| Status: | Published version |
| Publication Date: | 2023 |
| Country: | España |
| Institution: | Universidad de Barcelona |
| Repository: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/223155 |
| Online Access: | https://hdl.handle.net/2445/223155 http://hdl.handle.net/10803/695209 |
| Access Level: | Open access |
| Keyword: | Càncer de pròstata Andrògens Metabolisme Prostate cancer Androgens Metabolism |
| Summary: | [eng] Most prostate cancer (PCa) patients who undergo Androgen Deprivation Therapy (ADT) exhibit clinical progression, resulting in the development of castration-resistant prostate cancer (CRPC), which is highly metastatic and frequently lethal. The androgen receptor (AR) is expressed at high levels in CRPC. However, clinical trials in CRPC patients have shown that treatment with abiraterone or enzalutamide, AR signaling inhibitors, can improve survival rates. Unfortunately, these antiandrogens, only provide a temporary delay in disease progression, and resistance almost invariably arises. The molecular mechanisms that underlie resistance to antiandrogens remain elusive, hindering the development of effective therapies. To obtain candidate genes (hits) that are responsible for the acquisition of resistance or sensibility to abiraterone, we conducted a genome-wide CRISPR inhibition (CRISPRi) screening utilizing a tumor cell line derived from a genetically engineered mouse model (GEMM) carrying the combined inactivation of p53 and Pten, namely de NPp53 model. We identified that targeting the NOX family of NAPDH oxidases, particularly Duox2, has synthetic lethal interaction with abiraterone exposure. Duox2 is known to play a role in the production of reactive oxygen species (ROS) and has been found to be overexpressed in various types of tumors, including PCa. Mechanistically, we demonstrate that abiraterone treatment leads to ROS generation, which can be prevented by Duox2 knock-down (KD). Through our in vitro studies, we have shown that targeting abiraterone-induced ROS either through silencing of Duox2 or inhibiting the NOX family, restores antiandrogens sensitivity. To further understand the mechanisms involved in abiraterone-induced ROS and the role of Duox2 in this regulation, we conducted RNA-seq analysis to find that hypoxia-signaling was upregulated by abiraterone in normoxic conditions (pseudohypoxia). However, we observed that Duox2 abrogation prevented this pseudohypoxia activation, indicating that this signaling pathway could potentially be activated as a resistance mechanism to abiraterone. In particular, we demonstrated that abiraterone treatment in NPp53 cells increases HIF-1α stabilization, leading to its accumulation at the protein level and subsequent activation of the associated transcriptional program. Furthermore, we found that the accumulation of HIF-1α upon exposure to antiandrogen was reduced by N-acetyl-L-cysteine, an antioxidant, or by Duox2 silencing, thus highlighting the central role for NAPDH oxidases as triggers of pseudohypoxia in abiraterone-induced ROS. Based on the established and widely accepted effect of hypoxia signaling activation on regulating glucose metabolism, we observed that abiraterone induces a metabolic shift towards glycolysis, as evidenced by the decreased contribution of oxidative phosphorylation to ATP production upon abiraterone treatment. Consequently, we propose that the activation of glycolysis is a pseudohypoxia-induced mechanism to sustain ATP levels and promote proliferation. Therefore, we propose a combination treatment to co-target AR and pseudohypoxia activation using inhibitors of AR signaling and HIF-1α, respectively. Remarkably, we found that whereas single treatments were ineffective, combining enzalutamide with PX-478 resulted in a significant reduction in tumor growth and increased survival in an orthotopic CRPC in vivo model. In summary, we have uncovered and validated an actionable mechanism of resistance to AR signaling inhibition based on the activation of hypoxia-signaling mediated by antiandrogen- induced ROS that can be targeted with HIF-1α inhibitors, thus highlighting the potential of this combined therapeutic approach for CRPC patients. |
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