The role of androgen therapy in prostate cancer: from testosterone replacement therapy to bipolar androgen therapy

Testosterone bounce predicts favorable prognoses for prostate cancer patients treated with degarelix

BACKGROUND

To clarify the clinical roles of changes in testosterone (T) levels with a cut-off level of 20 ng/dL as predictive factors for prostate cancer patients treated with degarelix acetate.

METHODS

A total of 120 prostate cancer patients who received hormone therapies with gonadotropin-releasing hormone antagonist degarelix acetate were retrospectively analyzed. The predictive values of nadir T levels, max T levels, T bounce, and other clinical factors were evaluated for overall survival (OS), cancer-specific survival (CSS), and progression-free survival (PFS). T bounce was defined as satisfying both nadir serum T levels of <20 ng/dL and max serum T levels of ≥20 ng/dL during hormone therapies.

RESULTS

In 120 prostate cancer patients, 16 (13%) patients did not achieve nadir T < 20 ng/dL, and 76 (63%) patients had max T ≥ 20 ng/dL. The median times to nadir T and max T are 108 and 312 days, respectively. T bounce was shown in 60 (50%) patients and is associated with favorable prognoses both for OS (p = 0.0019) and CSS (p = 0.0013) but not for PFS (p = 0.92). While in the subgroup analyses of the patients with the progression of the first-line hormone therapies, T bounce predicts favorable OS (p = 0.0015) and CSS (p = 0.0013) after biochemical recurrence.

CONCLUSIONS

The present study revealed that T bounce with cut-off levels of 20 ng/dL is a promising biomarker that predicts OS and CSS for prostate cancer patients treated with degarelix acetate.

Selective modulation of estrogen receptor in obese men with androgen deficiency: A systematic review and meta-analysis

BACKGROUND

Although selective estrogen receptor modulators have been proposed as a treatment for men with central functional hypogonadism, only a few data have been produced in men with obesity-related functional androgen deficiency.

OBJECTIVE

To determine whether and to what extent selective estrogen receptor modulators are an effective and safe therapy in men with obesity-related functional androgen deficiency.

MATERIALS AND METHODS

A thorough search of PubMed, Web of Science, Scopus, and Cochrane Library databases was performed to identify studies comparing testosterone levels before and after treatment. Mean differences with 95% coefficient intervals were combined using random effects models. Funnel plot, Egger's test, and trim-and-fill analysis were used to assess publication bias.

RESULTS

Seven studies met the inclusion criteria providing information on 292 men with obesity-related functional androgen deficiency treated with clomiphene citrate (12.5-50 mg daily) or enclomiphene citrate (12.5-25 mg daily) for 1.5-4 months. The pooled estimates indicated a significant increase in testosterone levels both with clomiphene (mean difference: 11.56 nmol/L; 95% coefficient interval: 9.68, 13.43; I2  = 69%, pfor heterogeneity  = 0.01) and enclomiphene citrate (mean difference: 7.50 nmol/L; 95% coefficient interval: 6.52, 8.48; I2  = 4%, pfor heterogeneity  = 0.37). After the exclusion of one study on severely obese men, who exhibited the highest response rate to clomiphene citrate, the heterogeneity disappeared (mean difference: 10.27 nmol/L; 95% coefficient interval: 9.39, 11.16; I2  = 0%, pfor heterogeneity  = 0.66). No publication bias was revealed by Egger's test and trim-and-fill analysis. No treatment-related unexpected findings regarding safety profile were registered.

DISCUSSION AND CONCLUSION

Treatment with clomiphene citrate and enclomiphene citrate may be an effective and safe alternative to testosterone replacement therapy in men with obesity-related functional androgen deficiency. Further long-term studies are warranted to define clinical reflections of the selective estrogen receptor modulators-induced increase in testosterone levels and to better clarify the safety profile.

Bipolar Androgen Therapy: When Excess Fuel Extinguishes the Fire

Androgen deprivation therapy (ADT) remains the cornerstone of advanced prostate cancer treatment. However, the progression towards castration-resistant prostate cancer is inevitable, as the cancer cells reactivate androgen receptor signaling and adapt to the castrate state through autoregulation of the androgen receptor. Additionally, the upfront use of novel hormonal agents such as enzalutamide and abiraterone acetate may result in long-term toxicities and may trigger the selection of AR-independent cells through "Darwinian" treatment-induced pressure. Therefore, it is crucial to develop new strategies to overcome these challenges. Bipolar androgen therapy (BAT) is one such approach that has been devised based on studies demonstrating the paradoxical inhibitory effects of supraphysiologic testosterone on prostate cancer growth, achieved through a variety of mechanisms acting in concert. BAT involves rapidly alternating testosterone levels between supraphysiological and near-castrate levels over a period of a month, achieved through monthly intramuscular injections of testosterone plus concurrent ADT. BAT is effective and well-tolerated, improving quality of life and potentially re-sensitizing patients to previous hormonal therapies after progression. By exploring the mechanisms and clinical evidence for BAT, this review seeks to shed light on its potential as a promising new approach to prostate cancer treatment.

Testosterone therapy in prostate cancer: is it still a controversy?

PURPOSE OF REVIEW

The benefits of testosterone therapy (TTh) in the hypogonadal male can be dramatic. Historically, TTh has been contraindicated in prostate cancer (PCa). Current evidence has redefined our understanding of the influence serum testosterone has on prostatic androgen activity. Increasing numbers of hypogonadal men with coexisting PCa emphasizes the importance of describing those who may safely receive TTh. This review aims to present literature that evaluates the efficacy and safety of TTh in men with coexisting PCa.

RECENT FINDINGS

Our study, a comprehensive review of published literature regarding TTh in men with a history of PCa, consisted of studies conducted from the 1940s to 2022. Our review discusses evidence in accordance with previous studies that TTh has a role in patients with localized PCa as it has not been reported to increase rates of recurrence or progression of PCa.

SUMMARY

The use of TTh in hypongonadal men with a localized PCa has been shown to have positive clinical outcomes without increasing the rate of disease progression or recurrence. Further research, in a randomized controlled setting, is warranted.

The Integration of Metabolomics with Other Omics: Insights into Understanding Prostate Cancer

Our understanding of prostate cancer (PCa) has shifted from solely caused by a few genetic aberrations to a combination of complex biochemical dysregulations with the prostate metabolome at its core. The role of metabolomics in analyzing the pathophysiology of PCa is indispensable. However, to fully elucidate real-time complex dysregulation in prostate cells, an integrated approach based on metabolomics and other omics is warranted. Individually, genomics, transcriptomics, and proteomics are robust, but they are not enough to achieve a holistic view of PCa tumorigenesis. This review is the first of its kind to focus solely on the integration of metabolomics with multi-omic platforms in PCa research, including a detailed emphasis on the metabolomic profile of PCa. The authors intend to provide researchers in the field with a comprehensive knowledge base in PCa metabolomics and offer perspectives on overcoming limitations of the tool to guide future point-of-care applications.

Clinical response in metastatic castration-resistant prostate cancer (mCRPC) cases treated with supra-physiological doses of testosterone: Bipolar androgen therapy

Androgen deprivation therapy is a standard of care for metastatic prostate cancer. A paradoxical approach utilizing high doses of testosterone in castration-resistant prostate cancer patients demonstrated clinical responses. Here, we report on four heavily pretreated Japanese patients (including one patient on hemodialysis) successfully treated with supra-physiological doses of testosterone.

Sympathetic signaling facilitates progression of neuroendocrine prostate cancer

The progression of prostate cancer (PC) into neuroendocrine prostate cancer (NEPC) is a major challenge in treating PC. In NEPC, the PC cells undergo neuroendocrine differentiation (NED); however, the exact molecular mechanism that triggers NED is unknown. Peripheral nerves are recently shown to promote PC. However, their contribution to NEPC was not studied well. In this study, we explored whether sympathetic neurosignaling contributes to NED. We found that human prostate tumors from patients that later developed metastases and castration-resistant prostate cancer (CRPC), a stage preceding to NEPC, have high sympathetic innervations. Our work revealed that high concentrations of the sympathetic neurotransmitter norepinephrine (NE) induces NED-like changes in PC cells in vitro, evident by their characteristic cellular and molecular changes. The NE-mediated NED was effectively inhibited by the Adrβ2 blocker propranolol. Strikingly, propranolol along with castration also significantly inhibited the development and progression of NEPC in vivo in an orthotopic NEPC model. Altogether, our results indicate that the NE-Adrβ2 axis is a potential therapeutic intervention point for NEPC.

RNA methylation and cancer treatment

To this date, over 100 different types of RNA modification have been identified. Methylation of different RNA species has emerged as a critical regulator of transcript expression. RNA methylation and its related downstream signaling pathways are involved in plethora biological processes, including cell differentiation, sex determination and stress response, and others. It is catalyzed by the RNA methyltransferases, is demethylated by the demethylases (FTO and ALKBH5) and read by methylation binding protein (YTHDF1 and IGF2BP1). Increasing evidence indicates that this process closely connected to cancer cell proliferation, cellular stress, metastasis, immune response. And RNA methylation related protein has been becoming a promising targets of cancer therapy. This review outlines the relationship between different types of RNA methylation and cancer, and some FTO inhibitors in cancer treatment.

Undesirable Status of Prostate Cancer Cells after Intensive Inhibition of AR Signaling: Post-AR Era of CRPC Treatment

Recent advances in prostate cancer (PC) research unveiled real androgen receptor (AR) functions in castration-resistant PC (CRPC). Moreover, AR still accelerates PC cell proliferation via the activation of several mechanisms (e.g., mutation, variants, and amplifications in CRPC). New-generation AR signaling-targeted agents, inhibiting extremely the activity of AR, were developed based on these incontrovertible mechanisms of AR-induced CRPC progression. However, long-term administration of AR signaling-targeted agents subsequently induces the major problem that AR (complete)-independent CRPC cells present neither AR nor prostate-specific antigen, including neuroendocrine differentiation as a subtype of AR-independent CRPC. Moreover, there are few treatments effective for AR-independent CRPC with solid evidence. This study focuses on the transformation mechanisms of AR-independent from AR-dependent CRPC cells and potential treatment strategy for AR-independent CRPC and discusses them based on a review of basic and clinical literature.