Inhibition of the androgen receptor by mineralocorticoids at levels physiologically achieved in serum in patients treated with abiraterone acetate

Remission of progressive metastatic castration-resistant prostate cancer during abiraterone therapy following unilateral adrenalectomy for a functioning adrenal adenoma

Despite advances and introduction of new therapies in the last decade, metastatic castration-resistant prostate cancer (mCRPC) has a poor prognosis. The development of androgen axis-targeted therapies such as abiraterone acetate, enzalutamide and darolutamide can prolong survival in mCPRC; however, resistance remains a barrier to prolonged response, necessitating exploration into resistance mechanisms and locoregional therapies. Here, we describe a patient with mCRPC that was progressing on abiraterone acetate. He was also found to have primary hyperaldosteronism from a functional adrenal adenoma, and thus he had a partial adrenalectomy to remove this tumour. Pathology confirmed an aldosterone-producing adrenal adenoma. After his adrenalectomy, he had a sharp decline in both his PSA (prostate specific antigen) and testosterone levels, and he enjoyed a year-long period of remission after his adrenalectomy. We propose several explanations for his response, the most likely being that his adenoma was producing both aldosterone and androgens. This is a unique case of mCRPC responding to partial adrenalectomy from a functional adrenal adenoma, and it raises insights that warrant further investigation into underlying mechanisms of resistance to androgen-targeted therapies.

Androgen receptor signaling and spatial chromatin organization in castration-resistant prostate cancer

Prostate cancer is one of the leading causes of cancer death and affects millions of men in the world. The American Cancer Society estimated about 34,500 deaths from prostate cancer in the United States in year 2022. The Androgen receptor (AR) signaling is a major pathway that sustains local and metastatic prostate tumor growth. Androgen-deprivation therapy (ADT) is the standard of care for metastatic prostate cancer patient and can suppress the tumor growth for a median of 2-3 years. Unfortunately, the malignancy inevitably progresses to castration-resistant prostate cancer (CRPC) which is more aggressive and no longer responsive to ADT. Surprisingly, for most of the CPRC patients, cancer growth still depends on androgen receptor signaling. Accumulating evidence suggests that CRPC cells have rewired their transcriptional program to retain AR signaling in the absence of androgens. Besides AR, other transcription factors also contribute to the resistance mechanism through multiple pathways including enhancing AR signaling pathway and activating other complementary signaling pathways for the favor of AR downstream genes expression. More recent studies have shown the role of transcription factors in reconfiguring chromatin 3D structure and regulating topologically associating domains (TADs). Pioneer factors, transcription factors and coactivators form liquid-liquid phase separation compartment that can modulate transcriptional events along with configuring TADs. The role of AR and other transcription factors on chromatin structure change and formation of condensate compartment in prostate cancer cells has only been recently investigated and appreciated. This review intends to provide an overview of transcription factors that contribute to AR signaling through activation of gene expression, governing 3D chromatin structure and establishing phase to phase separation. A more detailed understanding of the spatial role of transcription factors in CRPC might provide novel therapeutic targets for the treatment of CRPC.

Abiraterone and spironolactone in prostate cancer: a combination to avoid

Objectives: Disease progression in metastatic castration-resistant prostate cancer (mCRPC) is dependent on androgen signaling. This case describes the complex adaptive androgen signaling mechanisms in mCRPC and illustrates that caution should be exercised when treating these patients with drugs influencing the androgen axis.Methods: Single case report and review of the literature.Results: We report the case of an 86-year-old man with mCRPC, treated with the secondary antihormonal agent abiraterone acetate. Following association of spironolactone to deal with symptoms related to mineralocorticoid excess, biochemical and radiographic disease progression occurred. Spironolactone was discontinued and 8 months after withdrawal, the patient continues to show a biochemical response to abiraterone.Conclusions: Although spironolactone generally exerts anti-androgenic effects, experimental evidence exists that it acts as an androgen receptor agonist in an androgen-depleted environment, capable of inducing prostate cancer proliferation. This is supported by the observations described in this case report. Therefore, spironolactone should be avoided in prostate cancer patients suffering from treatment-associated side effects of abiraterone.

Prognostic significance of antihypertensive agents in men with castration-resistant prostate cancer

PURPOSE

Comorbidity with hypertension (HTN) may affect the outcome of castration-resistant prostate cancer (CRPC). In this study, we evaluated the prognostic impact of antihypertensive agents in patients with CRPC treated with androgen receptor axis-targeting (ARAT) agents or docetaxel chemotherapy.

PATIENTS AND METHODS

This study included 156 Japanese men with CRPC who were treated with ARAT agents (n = 85) or docetaxel (n = 71) at our hospital between 2008 and 2017. Associations between clinicopathological factors, HTN status, progression-free survival (PFS) and overall survival (OS) were evaluated by univariate and multivariate analysis.

RESULTS

When adjusted for age, prostate-specific antigen levels at pretreatment, Gleason score, and clinical M-stage, comorbid HTN was significantly associated with better OS (hazards ratio, 95% confidence interval: 0.41, 0.21-0.77; P = 0.0051), but not with PFS (hazards ratio, 95% confidence interval: 0.64, 0.38-1.11; P = 0.11) in patients treated with ARAT agent. However, HTN was not associated with PFS or OS for patients treated with docetaxel.

CONCLUSIONS

Use of antihypertensive agents has prognostic significance for patients with CRPC treated with ARAT agent, but not docetaxel.

The Role of Nuclear Receptors in Prostate Cancer

The nuclear receptor (NR) superfamily consists of 48 members that are divided into seven subfamilies. NRs are transcription factors that play an important role in a number of biological processes. The NR superfamily includes androgen receptor, which is a key player in prostate cancer pathogenesis, suggesting the functional roles of other NRs in prostate cancer. The findings on the roles of NRs in prostate cancer thus far have shown that several NRs such as vitamin D receptor, estrogen receptor β, and mineralocorticoid receptor play antioncogenic roles, while other NRs such as peroxisome proliferator-activated receptor γ and estrogen receptor α as well as androgen receptor play oncogenic roles. However, the roles of other NRs in prostate cancer remain controversial or uninvestigated. Further research on the role of NRs in prostate cancer is required and may lead to the development of novel preventions and therapeutics for prostate cancer.

Mineralocorticoid receptor signaling affects therapeutic effect of enzalutamide

BACKGROUND

Corticosteroids play important roles in prostate cancer therapeutics. However, their role when combined with enzalutamide remains obscure. Then, we aimed to elucidate the functional and clinical impact of corticosteroids on steroid receptors in androgen receptor (AR)-targeting therapy utilizing enzalutamide.

METHODS

The therapeutic effect was studied according to concomitant use of corticosteroids in 86 men treated with enzalutamide. The sensitivity to various agents was evaluated using cytotoxicity assays in prostate cancer cells. Gene expression levels were evaluated by quantitative real-time polymerase chain reaction in prostate cancer cells and tissues.

RESULTS

The therapeutic effect of enzalutamide was particularly lessened with concomitant treatment with dexamethasone. Consistently, dexamethasone increased cellular resistance to enzalutamide while prednisolone and aldosterone decreased cellular resistance to enzalutamide in prostate cancer cells. Inversely, mineralocorticoid receptor (MR) knockdown augmented the activity of AR signaling and the cellular resistance to enzalutamide.

CONCLUSIONS

MR plays a critical role in resistance to AR-targeting therapies, which may be overcome by activation of MR signaling.

WOMEN IN CANCER THEMATIC REVIEW: New roles for nuclear receptors in prostate cancer

Prostate cancer has, for decades, been treated by inhibiting androgen signalling. This is effective in the majority of patients, but inevitably resistance develops and patients progress to life-threatening metastatic disease - hence the quest for new effective therapies for 'castrate-resistant' prostate cancer (CRPC). Studies into what pathways can drive tumour recurrence under these conditions has identified several other nuclear receptor signalling pathways as potential drivers or modulators of CRPC.The nuclear receptors constitute a large (48 members) superfamily of transcription factors sharing a common modular functional structure. Many of them are activated by the binding of small lipophilic molecules, making them potentially druggable. Even those for which no ligand exists or has yet been identified may be tractable to activity modulation by small molecules. Moreover, genomic studies have shown that in models of CRPC, other nuclear receptors can potentially drive similar transcriptional responses to the androgen receptor, while analysis of expression and sequencing databases shows disproportionately high mutation and copy number variation rates among the superfamily. Hence, the nuclear receptor superfamily is of intense interest in the drive to understand how prostate cancer recurs and how we may best treat such recurrent disease. This review aims to provide a snapshot of the current knowledge of the roles of different nuclear receptors in prostate cancer - a rapidly evolving field of research.