A clinical-grade liquid biomarker detects neuroendocrine differentiation in prostate cancer

The 29th Annual Prostate Cancer Foundation Scientific Retreat Report

BACKGROUND

The 29th Annual Prostate Cancer Foundation (PCF) Scientific Retreat was held from October 27 to 29, 2022, at the Omni La Costa Resort in Carlsbad, CA. This was the first-ever hybrid PCF Retreat.

METHODS

The Annual PCF Scientific Retreat is a prominent international scientific gathering centered on groundbreaking, unpublished, and influential studies in basic, translational, and clinical prostate cancer research. It also covers research from related fields with a strong potential for influencing prostate cancer research and patient care.

RESULTS

Key areas of research that were focused on at the 2022 PCF Retreat included: (i) the contributions of molecular and genomic factors to prostate cancer disparities; (ii) novel clinical trial updates; (iii) lessons from primary prostate cancer; (iv) lessons from single-cell studies; (v) genetic, epigenetic, epitranscriptomic and posttranslational mechanisms and clinical heterogeneity in prostate cancer; (vi) biology of neuroendocrine and lineage-plastic prostate cancer; (vii) next generation prostate cancer theranostics and combination therapies; (viii) the biology and therapeutic potential of targeting phosphoinositide 3-kinases pathways; (ix) combining immunomodulatory treatments for prostate cancer; (x) novel gamma delta (γδ) T-cell therapy platforms for oncology; and (xi) lessons from other cancers.

CONCLUSIONS

This article provides a summary of the presentations from the 2022 PCF Scientific Retreat. By disseminating this knowledge, we hope to enhance our understanding of the present research landscape and guide future strides in both prostate cancer research and patient care.

H19 in Serum Extracellular Vesicles Reflects Resistance to AR Axis-targeted Therapy Among CRPC Patients

BACKGROUND/AIM

We aimed to evaluate the changes of androgen receptor (AR) signaling-related long non-coding RNAs (lncRNAs) in serum extracellular vesicles (EVs) from prostate cancer (PC) patients, in order to identify novel biomarkers for AR axis-targeted therapy (ARAT)-resistance among castration-resistant PC (CRPC) patients.

PATIENTS AND METHODS

EVs were isolated from 2 patients before and after acquiring ARAT-resistance. RNA profiling of EVs was performed by RNA-sequencing. The expression levels of selected lncRNAs in EVs were analyzed by digital droplet PCR (ddPCR) in 58 localized and 14 metastatic PC patients at diagnosis, 7 ARAT-naïve and 6 ARAT-resistant CRPC patients. LncRNA H19 expression in PC tissue was examined using published data. In order to analyze the role of H19, the prognosis was analyzed in PC patients and proteomic analysis was performed in 22Rv1 PC cells.

RESULTS

RNA-sequencing revealed that AR-regulated RNAs were most enriched in EVs after acquiring ARAT-resistance. Among them, up-regulation of AR signaling-related lncRNAs (PCAT1, H19, HOXA-11AS, ZEB1-AS1, ARLNC1, PART1, CTBP1-AS and PCA3) was confirmed by ddPCR. H19 contained in EVs (EV-H19) was significantly increased among ARAT-resistant patients compared to ARAT-naïve CRPC or metastatic PC patients. In PC tissue, H19 was negatively correlated with AR protein and AR-activity score and up-regulated in neuroendocrine CRPC tissue with low AR expression. Furthermore, EV-H19 expression was significantly associated with worse outcome to androgen-deprivation therapy. Proteomic analysis demonstrated that H19 knockdown enhanced PC-related protein expression.

CONCLUSION

EV-H19 may negatively correlate with AR-signaling activity and could be a marker to diagnose ARAT-resistance among CRPC patients.

Genetic and epigenetic features of neuroendocrine prostate cancer and their emerging applications

Prostate cancer is the second most prevalent cancer in men globally. De novo neuroendocrine prostate cancer (NEPC) is uncommon at initial diagnosis, however, (treatment-induced) t-NEPC emerges in up to 25% of prostate adenocarcinoma (PRAD) cases treated with androgen deprivation, carrying a drastically poor prognosis. The transition from PRAD to t-NEPC is underpinned by several key genetic mutations; TP53, RB1, and MYCN are the main genes implicated, bearing similarities to other neuroendocrine tumours. A broad range of epigenetic alterations, such as aberrations in DNA methylation, histone post-translational modifications, and non-coding RNAs, may drive lineage plasticity from PRAD to t-NEPC. The clinical diagnosis of NEPC is hampered by a lack of accessible biomarkers; recent advances in liquid biopsy techniques assessing circulating tumour cells and ctDNA in NEPC suggest that the advent of non-invasive means of monitoring progression to NEPC is on the horizon. Such techniques are vital for NEPC management; diagnosis of t-NEPC is crucial for implementing effective treatment, and precision medicine will be integral to providing the best outcomes for patients.

Single Center Experience with a 4-Week 177Lu-PSMA-617 Treatment Interval in Patients with Metastatic Castration-Resistant Prostate Cancer

Background: 177Lu-PSMA-617 is a promising theragnostic treatment for metastatic castration-resistant prostate cancer (mCRPC). However, both the optimal treatment dose and interval in mCRPC and the rate of identification of responders from non-responders among possible treatment candidates are unknown. Methods: 62 men with mCRPC who were treated with 177Lu-PSMA-617 during 1/2017−2/2019 were included in the study. Treatment responses, overall survival (OS) and progression free survival (PFS) were determined. The median follow-up time was 1.4 years (IQR 0.5−2.2). Tumor volume of metastases (MTV), SUVmax and tumor lesion activity (TLA) were quantitated from pre-treatment PSMA PET/CT images together with pre-treatment PSA. Results: An average of three treatment cycles (2−5) were given within a four-week interval. PFS was 4.9 months (2.4−9.6) and OS was 17.2 months (6−26.4). There were no major adverse events reported. A significant PSA response of >50% was found in 58.7% of patients, which was significantly associated with longer OS, p < 0.004. PSA response was not associated with staging PSMA-derived parameters. Conclusions: 177Lu-PSMA-617 treatment in four-week intervals was safe and effective. Almost 60% of patients had a significant PSA response, which was associated with better OS. Pre-treatment PSA kinetics or staging PSMA PET/CT-derived parameters were not helpful in identifying treatment responders from non-responders; better biomarkers are needed to aid in patient selection.