Prostate-specific antigen: An unfamiliar protein in the human salivary glands

OBJECTIVES

The presence of prostate-specific antigen (PSA) in saliva and salivary glands has been reported. Nevertheless, its release pathway in these glands remains to be elucidated. Here, we showed PSA subcellular distribution focusing on its plausible route in human salivary parenchyma.

MATERIALS AND METHODS

Sections of parotid and submandibular glands were subjected to the immunohistochemical demonstration of PSA by the streptavidin-biotin method revealed by alkaline phosphatase. Moreover, ultrathin sections were collected on nickel grids and processed for immunocytochemical analysis, to visualize the intracellular distribution pattern of PSA through the observation by transmission electron microscopy.

RESULTS

By immunohistochemistry, in both parotid and submandibular glands PSA expression was detected in serous secretory acini and striated ducts. By immunocytochemistry, immunoreactivity was retrieved in the cytoplasmic compartment of acinar and ductal cells, often associated with small cytoplasmic vesicles. PSA labeling appeared also on rough endoplasmic reticulum and in the acini's lumen. A negligible PSA labeling appeared in most of the secretory granules of both glands.

CONCLUSIONS

Our findings clearly support that human parotid and submandibular glands are involved in PSA secretion. Moreover, based on the immunoreactivity pattern, its release in oral cavity would probably occur by minor regulated secretory or constitutive-like secretory pathways.

Upcycling HOXB13: enhancing prostate cancer detection with a novel antibody†

Prostate cancer is one of the most prevalent and, upon metastasis, deadliest cancers in men. Timely identification is essential for effective treatment. Furthermore, accurate determination of prostatic origin is crucial for personalized therapy once the cancer has spread. However, current prostate cancer screening methods are lacking. A recent article in The Journal of Pathology addresses this issue by utilizing an improved antibody to reevaluate HOXB13 as a lineage marker for prostate cancer. The study's findings support the concept that, despite decreased expression in advanced prostate cancer, HOXB13 remains highly suitable for determining prostatic origin due to its androgen receptor independence, high specificity, and sensitivity. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Inhibition of orthotopic castration-resistant prostate cancer growth and metastasis in mice by JC VLPs carrying a suicide gene driven by the PSA promoter

Metastatic castration-resistant prostate cancer (mCRPC) is challenging to treat. Virus-like particles (VLPs), originating from JC polyomavirus (JCPyV) and carrying a suicide gene driven by the PSA promoter (PSAtk-VLPs), can inhibit tumor growth in animal models of human prostate cancer. However, the efficacy of suppression of orthotopic PCa growth and metastasis by PSAtk-VLPs remains undetermined. Here, we established an iRFP stable expression CRPC cell line suitable for deep-tissue observation using fluorescence molecular tomography (FMT). These cells were implanted into murine prostate tissue, and PSAtk-VLPs were systemically administered via the tail vein along with the prodrug ganciclovir (GCV), allowing for the real-time observation of orthotopic prostate tumor growth and CRPC tumor metastasis. Our findings demonstrated that systemic PSAtk-VLPs administration with GCV and subsequent FMT scanning facilitated real-time observation of the suppressed growth in mouse iRFP CRPC orthotopic tumors, which further revealed a notable metastasis rate reduction. Systemic PSAtk-VLPs and GCV administration effectively inhibited orthotopic prostate cancer growth and metastasis. These findings suggest the potential of JCPyV VLPs as a promising vector for mCRPC gene therapy. Conclusively, systemically administered JCPyV VLPs carrying a tissue-specific promoter, JCPyV VLPs can protect genes within the bloodstream to be specifically expressed in specific organs.

177 Lu-PSMA-617 Therapy in a Case of Metastatic Castration-Resistant Prostate Cancer

ABSTRACT

We report a 65-year-old man with metastatic castration-resistant prostate cancer who was treated with 2 cycles of 177 Lu-PSMA-617 therapy. PET/CT imaging of 68 Ga-PSMA-11 revealed a complete metabolic response (PERCIST1.0) after therapy. The prostate-specific antigen concentration drastically decreased (97.7% down).

Prostate-specific membrane antigen radioguided surgery with negative histopathology: an in-depth analysis

PURPOSE

To identify reasons for negative histopathology of specimens from prostate-specific membrane antigen (PSMA) radioguided surgery (PSMA-RGS) in recurrent prostate cancer (PCa) after prostatectomy.

METHODS

Of 302 patients who underwent PSMA-RGS, 17 (5.6%) demonstrated a negative histopathology. Preoperative data, PSMA PET, PSMA SPECT, and follow-up information were analyzed retrospectively to differentiate true/false positive (TP/FP) from true/false negative (TN/FN) lesions.

RESULTS

The median prostate-specific antigen at PET was 0.4 ng/ml (interquartile range [IQR] 0.3-1.2). Twenty-five index lesions (median short axis 7 mm, IQR 5-8; median long-axis 12 mm, IQR 8-17) had a median SUVmax of 4 (IQR 2.6-6; median PSMA expression score 1, IQR 1-1). Six lesions were TP, twelve were FP, one was TN, and six remained unclear. All TP lesions were in the prostatic fossa or adjacent to the internal iliac arteries. Three suspected local recurrences were FP. All FP lymph nodes were located at the distal external iliac arteries or outside the pelvis. A low PSMA-expressing TN node was identified next to a common iliac artery. Unclear lesions were located next to the external iliac arteries or outside the pelvis.

CONCLUSION

In most cases with a negative histopathology from PSMA-RGS, lesions were FP on PSMA PET. Unspecific uptake should be considered in low PSMA-expressing lymph nodes at the distal external iliac arteries or outside the pelvis, especially if no PSMA-positive lymph nodes closer to the prostatic fossa are evident. Rarely, true positive metastases were missed by surgery or histopathology.

RNA-binding protein 14 promotes phase separation to sustain prostate specific antigen expression under androgen deprivation in human prostate cancer

Castration-resistant prostate cancer (CRPC) is a big challenge in managing prostate cancer patients. The androgen receptor (AR) pathway is a major driver even in CRPC under androgen deprivation. The mechanism in maintaining of the AR pathway under androgen deprivation remains elusive. The recent discovery of biomolecular condensate, a membrane-less intracellular construct formed by liquid-liquid phase separation (LLPS), that facilitate molecular assembly, encouraged the re-screening of our previous microarray data list. We selected Rbm14 as a target molecule for further analysis because it works as a coactivator of nuclear receptors as well as it facilitates formation of biomolecular condensates via its intrinsically disordered region. GFP-tagged Rbm14 transfected into HEK293T cells formed droplet-like puncta, which diminished following treatment with 1,6-hexanediol. Droplet-like structures were also observed in immunofluorescence for endogenous RBM14 of PC-3 and DU145 cells. Luciferase assay revealed that Rbm14 enhanced androgen-responsive element (ARE)-mediated reporter activity in all conditions with or without testosterone and AR. Co-immunoprecipitation confirmed the Rbm14-AR interaction. Long non-coding RNAs, including NEAT1, SRA1, and HOTAIR, were also interacted with Rbm14. Small interfering RNAs of NEAT1 reduced ARE-mediated reporter activity, while transfection of SRA1 and HOTAIR enhance the reporter activity. Treatment with 1,6-hexanediol as well as transfection with a dominant-negative splice variant of Rbm14 reduced expression of prostate specific antigen (PSA), a prototype of androgen-regulated gene, in LNCaP, PC-3, and DU145 cells under androgen deprivation. Immunohistochemically, RBM14 expression was substantially upregulated in prostate cancer tissues after androgen deprivation therapy than in untreated tumors. In conclusion, RBM14 is a novel factor involved in maintenance of PSA expression via phase separation under androgen deprivation in prostate cancer.

Clinical impact of Prostate-Specific Membrane Antigen Positron Emission Tomography (PET) on intensification or deintensification of advanced renal cell carcinoma management

PURPOSE

There is an emerging role of the use of Prostate-Specific Membrane Antigen (PSMA) Positron Emission Tomography (PET) in renal cell carcinoma. Herein, we report our experience in use of PSMA PET in recurrent or metastatic renal cell carcinoma (RCC).

METHODS

A retrospective analysis of all patients who underwent PSMA PET for suspected recurrent or de-novo metastatic RCC between 2015 and 2020 at three institutions was performed. The primary outcome was change in management (intensification or de-intensification) following PSMA PET scan. Secondary outcomes included histopathological correlation of PSMA avid sites, comparison of sites of disease on PSMA PET to diagnostic CT and time to systemic treatment.

RESULTS

Prostate-Specific Membrane Antigen (PSMA) Expression Predicts Need for Early Treatment in Prostate Cancer Patients Managed with Active Surveillance

Metabolic dysregulation is an early event in carcinogenesis. Here, we examined the expression of enzymes involved in de novo lipogenesis (ATP-citrate lyase: ACLY), glucose uptake (Glucose Transporter 1: GLUT1), and folate-glutamate metabolism (Prostate-Specific Membrane Antigen: PSMA) as potential biomarkers of risk for early prostate cancer progression. Patients who were managed initially on active surveillance with a Gleason score of 6 or a low-volume Gleason score of 7 (3 + 4) were accrued from a prostate cancer diagnostic assessment program. Patients were asked to donate their baseline diagnostic biopsy tissues and permit access to their clinical data. PSMA, GLUT1, and ACLY expression were examined with immunohistochemistry (IHC) in baseline biopsies, quantitated by Histologic Score for expression in benign and malignant glands, and compared with patient time remaining on active surveillance (time-on-AS). All three markers showed trends for elevated expression in malignant compared to benign glands, which was statistically significant for ACLY. On univariate analysis, increased PSMA and GLUT1 expression in malignant glands was associated with shorter time-on-AS (HR: 5.06, [CI 95%: 1.83-13.94] and HR: 2.44, [CI 95%: 1.10-5.44], respectively). Malignant ACLY and benign gland PSMA and GLUT1 expression showed non-significant trends for such association. On multivariate analysis, overexpression of PSMA in malignant glands was an independent predictor of early PC progression (p = 0.006). This work suggests that the expression of metabolic enzymes determined by IHC on baseline diagnostic prostate biopsies may have value as biomarkers of risk for rapid PC progression. PSMA may be an independent predictor of risk for progression and should be investigated further in systematic studies.

Auraptene Enhances AMP-Activated Protein Kinase Phosphorylation and Thereby Inhibits the Proliferation, Migration and Expression of Androgen Receptors and Prostate-Specific Antigens in Prostate Cancer Cells

Citrus hassaku extract reportedly activates AMPK. Because this extract contains an abundance of auraptene, we investigated whether pure auraptene activates AMPK and inhibits proliferation using prostate cancer cell lines. Indeed, auraptene inhibited the proliferation and migration of LNCaP cells and induced phosphorylation of AMPK or its downstream ACC in LNCaP, PC3, and HEK-293 cells, but not in DU145 cells not expressing LKB1. In addition, the mTOR-S6K pathway, located downstream from activated AMPK, was also markedly suppressed by auraptene treatment. Importantly, it was shown that auraptene reduced androgen receptor (AR) and prostate-specific antigen (PSA) expressions at both the protein and the mRNA level. This auraptene-induced downregulation of PSA was partially but significantly reversed by treatment with AMPK siRNA or the AMPK inhibitor compound C, suggesting AMPK activation to, at least partially, be causative. Finally, in DU145 cells lacking the LKB1 gene, exogenously induced LKB1 expression restored AMPK phosphorylation by auraptene, indicating the essential role of LKB1. In summary, auraptene is a potent AMPK activator that acts by elevating the AMP/ATP ratio, thereby potentially suppressing prostate cancer progression, via at least three molecular mechanisms, including suppression of the mTOR-S6K pathway, reduced lipid synthesis, and AR downregulation caused by AMPK activation.

N6-methyladenosine demethylase FTO related to hyperandrogenism in PCOS via AKT pathway

BACKGROUND

Polycystic ovary syndrome (PCOS) was known as the common endocrine disease in women, featured as hyperandrogenism, ovulation disorders, etc. Fat mass and obesity-associated protein (FTO), a m6A demethylase, is abnormal in the occurrence of ovarian diseases. However, the mechanism of FTO in the pathogenesis of PCOS is still unclear.

METHODS

The level of FTO in clinical samples, PCOS rat with hyperandrogenism and granulosa cells (GCs) lines effected by DHT were investigated by ELISA, qRT-PCR, WB, and IHC, while m6A RNA methylation level was studied by m6A Colorimetric and androgen level was tested through ELISA. Changes in steroid hormone synthetase and androgen receptor (AR)/prostate-specific antigen (PSA) levels in vitro were visualized by WB after transient transfection silenced FTO. The effect of DHT combined with FTO inhibitor meclofenamic acid (MA) on FTO, AR/PSA, and AKT phosphorylation were also demonstrated by WB. The co-localization of FTO and AR in KGN cells was analyzed by confocal microscopy, and the physiological interaction between FTO and AR was studied by Co-IP assay. The effect of FTO-specific inhibitor MA, AKT phosphorylation inhibitor LY294002, and the combined them on GCs proliferation and cell cycle were evaluated by drug combination index, EDU assay, and flow cytometry analysis.

RESULTS

FTO expression was upregulated in follicular fluid and GCs in PCOS patients clinically. The high FTO expression in patients was negative with the level of m6A, but positive with the level of androgen. The upregulation of FTO was accompanied with a decrease in the level of m6A in PCOS rat with hyperandrogenism. Dihydrotestosterone (DHT) promoted the FTO expression and inhibited m6A content as a dose-dependent way in vitro. In contrast, suppression of FTO with siRNA attenuated the expression of steroid hormone synthetase such as CYP11A1, CYP17A1, HSD11B1, HSD3B2 except CYP19A1 synthetase, ultimately inducing the decrease of androgen level. Suppression of FTO also decreased the biological activity of androgen through downregulation AR/PSA. MA treatment as the specific FTO antagonist decreased cell survival in time- and dose-dependent way in GCs lines. Correspondingly, MA treatment decreased the expression of FTO, AR/PSA expression, and AKT phosphorylation in the presence of DHT stimulation. Additionally, we also speculate there is a potential relation between FTO and AR according to FTO was co-localized and interacted with AR in KGN cells. Compared with AKT phosphorylation inhibitor LY294002 or MA alone, LY294002 combined with MA synergistically inhibited cell survival and increased G2/M phase arrest in GC line.

CONCLUSIONS

We first evaluated the correlation of FTO and m6A in PCOS clinically, and further explored the mechanism between FTO and hyperandrogenism in PCOS animal and cell models. These findings contributed the potential therapy by targeting the FTO for hyperandrogenism in PCOS.

Characterization and root cause analysis of immunogenicity to pasotuxizumab (AMG 212), a prostate-specific membrane antigen-targeting bispecific T-cell engager therapy

Introduction

In oncology, anti-drug antibody (ADA) development that significantly curtails response durability has not historically risen to a level of concern. The relevance and attention ascribed to ADAs in oncology clinical studies have therefore been limited, and the extant literature on this subject scarce. In recent years, T cell engagers have gained preeminence within the prolific field of cancer immunotherapy. These drugs whose mode of action is expected to potently stimulate anti-tumor immunity, may potentially induce ADAs as an unintended corollary due to an overall augmentation of the immune response. ADA formation is therefore emerging as an important determinant in the successful clinical development of such biologics.

Methods

Here we describe the immunogenicity and its impact observed to pasotuxizumab (AMG 212), a prostate-specific membrane antigen (PSMA)-targeting bispecific T cell engager (BiTE®) molecule in NCT01723475, a first-in-human (FIH), multicenter, dose-escalation study in patients with metastatic castration-resistant prostate cancer (mCRPC). To explain the disparity in ADA incidence observed between the SC and CIV arms of the study, we interrogated other patient and product-specific factors that may have explained the difference beyond the route of administration.

Results

Treatment-emergent ADAs (TE-ADA) developed in all subjects treated with at least 1 cycle of AMG 212 in the subcutaneous (SC) arm. These ADAs were neutralizing and resulted in profound exposure loss that was associated with contemporaneous reversal of initial Prostate Surface Antigen (PSA) responses, curtailing durability of PSA response in patients. Pivoting from SC to a continuous intravenous (CIV) administration route remarkably yielded no subjects developing ADA to AMG 212. Through a series of stepwise functional assays, our investigation revealed that alongside a more historically immunogenic route of administration, non-tolerant T cell epitopes within the AMG 212 amino acid sequence were likely driving the high-titer, sustained ADA response observed in the SC arm.

Discussion

These mechanistic insights into the AMG 212 ADA response underscore the importance of performing preclinical immunogenicity risk evaluation as well as advocate for continuous iteration to better our biologics.

Albumin-Binding and Conventional PSMA Ligands in Combination with 161Tb: Biodistribution, Dosimetry, and Preclinical Therapy

The favorable decay characteristics of 161Tb attracted the interest of clinicians in using this novel radionuclide for radioligand therapy (RLT). 161Tb decays with a similar half-life to 177Lu, but beyond the emission of β--particles and γ-rays, 161Tb also emits conversion and Auger electrons, which may be particularly effective to eliminate micrometastases. The aim of this study was to compare the dosimetry and therapeutic efficacy of 161Tb and 177Lu in tumor-bearing mice using SibuDAB and PSMA-I&T, which differ in their blood residence time and tumor uptake. Methods: [161Tb]Tb-SibuDAB and [161Tb]Tb-PSMA-I&T were evaluated in vitro and investigated in biodistribution, imaging, and therapy studies using PC-3 PIP tumor-bearing mice. The 177Lu-labeled counterparts served for dose calculations and comparison of therapeutic efficacy. The tolerability of RLT in mice was monitored on the basis of body mass, blood plasma parameters, blood cell counts, and the histology of relevant organs and tissues. Results: The prostate-specific membrane antigen (PSMA)-targeting radioligands, irrespective of whether labeled with 161Tb or 177Lu, showed similar in vitro data and comparable tissue distribution profiles. As a result of the albumin-binding properties, [161Tb]Tb/[177Lu]Lu-SibuDAB had an enhanced blood residence time and higher tumor uptake (62%-69% injected activity per gram at 24 h after injection) than [161Tb]Tb/[177Lu]Lu-PSMA-I&T (30%-35% injected activity per gram at 24 h after injection). [161Tb]Tb-SibuDAB inhibited tumor growth more effectively than [161Tb]Tb-PSMA-I&T, as can be ascribed to its 4-fold increased absorbed tumor dose. At any of the applied activities, the 161Tb-based radioligands were therapeutically more effective than their 177Lu-labeled counterparts, as agreed with the approximately 40% increased tumor dose of 161Tb compared with that of 177Lu. Under the given experimental conditions, no obvious adverse events were observed. Conclusion: The data of this study indicate the promising potential of 161Tb in combination with SibuDAB for RLT of prostate cancer. Future clinical studies using 161Tb-based RLT will shed light on a potential clinical benefit of 161Tb over 177Lu.

Characterisation of cell lines derived from prostate cancer patients with localised disease

BACKGROUND

Prostate cancer is a broad-spectrum disease, spanning from indolent to a highly aggressive lethal malignancy. Prostate cancer cell lines are essential tools to understanding the basic features of this malignancy, as well as in identifying novel therapeutic strategies. However, most cell lines routinely used in prostate cancer research are derived from metastatic disease and may not fully elucidate the molecular events underlying the early stages of cancer development and progression. Thus, there is a need for new cell lines derived from localised disease to better span the disease spectrum.

METHODS

Prostatic tissue from the primary site, and adjacent non-cancerous tissue was obtained from four patients with localised disease undergoing radical prostatectomy. Epithelial cell outgrowths were immortalised with human papillomavirus type 16 (HPV16) E6 and E7 to establish monoclonal cell lines. Chromosomal ploidy was imaged and STR profiles were determined. Cell morphology, colony formation and cell proliferation characteristics were assessed. Androgen receptor (AR) expression and AR-responsiveness to androgen treatment were analysed by immunofluorescence and RT-qPCR, respectively. RNA-seq analysis was performed to identify prostate lineage markers and expression of prostate cancer tumorigenesis-related genes.

RESULTS

Two benign cell lines derived from non-cancer cells (AQ0420 and AQ0396) and two tumour tissue derived cancer cell lines (AQ0411 and AQ0415) were immortalised from four patients with localised prostatic adenocarcinoma. The cell lines presented an epithelial morphology and a slow to moderate proliferative rate. None of the cell lines formed anchorage independent colonies or displayed AR-responsiveness. Comparative RNA-seq expression analysis confirmed the prostatic lineage of the four cell lines, with a distinct gene expression profile from that of the metastatic prostate cancer cell lines, PC-3 and LNCaP.

CONCLUSIONS

Comprehensive characterization of these cell lines may provide new in vitro tools that could bridge the current knowledge gap between benign, early-stage and metastatic disease.

The effect of encomir-93 mimic transfection on the expression of miR-93 and PSA and androgen receptor in prostate cancer LNcap cell line

OBJECTIVES

Prostate cancer (PCa) is one of the most common cancers in men with high mortality rate which is a major concern for men's health. However, the molecular mechanisms remain poorly understood. miR-93 is an important oncogene which may have important function in prostate cancer.So, this study aimed to predict that encomir-93 mimic transfection on the expression of miR-93 and PSA and AR in prostate cancer LNcap cell line.

METHODS

Lymph node carcinoma of the prostate (LNCaP) was cultured and then miR-93 mimics was designed, synthesized and the transfected to LNCaP. The expression level of prostate-specific antigen (PSA) and androgen receptor (AR) was determined via Real-time PCR after treated with 15 pmol of miR-93 mimics.

RESULTS

miR-93 mimic transfection led to significant increase in PSA and AR expression in comparison with control group (p≤0.05).

CONCLUSIONS

The miR-93 and its target genes has important role in PCa progression via enhancement in PSA and AR expression. Further research on the function of the miR-93 and its target genes in tumorgenesis and progression PCa could be helpful for the treatment of prostate cancer.

Improved Prostate-Specific Membrane Antigen (PSMA) Stimulation Using a Super Additive Effect of Dutasteride and Lovastatin In Vitro

Prostate-specific membrane antigen (PSMA)-based imaging improved the detection of primary, recurrent and metastatic prostate cancer. However, in certain patients, a low PSMA surface expression can be a limitation for this promising diagnostic tool. Pharmacological induction of PSMA might be useful to further improve the detection rate of PSMA-based imaging. To achieve this, we tested dutasteride (Duta)-generally used for treatment of benign prostatic enlargement-and lovastatin (Lova)-a compound used to reduce blood lipid concentrations. We aimed to compare the individual effects of Duta and Lova on cell proliferation as well as PSMA expression. In addition, we tested if a combination treatment using lower concentrations of Duta and Lova can further induce PSMA expression. Our results show that a treatment with ≤1 μM Duta and ≥1 μM Lova lead to a significant upregulation of whole and cell surface PSMA expression in LNCaP, C4-2 and VCaP cells. Lower concentrations of Duta and Lova in combination (0.5 μM Duta + 0.5 μM Lova or 0.5 μM Duta + 1 μM Lova) were further capable of enhancing PSMA protein expression compared to a single compound treatment using higher concentrations in all tested cell lines (LNCaP, C4-2 and VCaP).

Value of Prostate-Specific Antigen Kinetics in Patients with Low-Risk Prostate Cancer under Active Surveillance

INTRODUCTION

This study analyzes the value of PSA kinetics, PSA speed (vPSA), and PSA doubling time (PSAdt), in patients with low-risk prostate cancer who are in an active surveillance (AS) program.

METHODS

An observational, retrospective, and longitudinal study of a sample of 86 patients included in AS program between January 2014 and October 2021 was conducted. A review of their medical records was performed, and PSA kinetics were calculated, analyzing the causes of discontinuation of the AS program and its relationship with PSA kinetics.

RESULTS

The mean age was 63.39 years, and the median follow-up was 62.55 months. The mean PSA at diagnosis was 8.27 ng/mL. A median of PSAdt of 62.55 months and 1.3 ng/mL/year for vPSA was obtained. 35 patients left the program, with a higher percentage of patients leaving with a PSAdt less than 36 months (73.7 vs. 31.1%) and a vPSA greater than 2 ng/mL/year (68.2 vs. 31.3%). The probability of permanence and the time of permanence in AS were statistically significantly higher for those patients with favorable kinetic parameters.

CONCLUSION

PSA kinetics is a parameter to take into account when making decisions to keep patients in an AS program.

Incidental Meningioma With Altered PSMA Expression After Systemic Hormone Therapy and Local Radiotherapy Detected by 68 Ga-PSMA PET/CT

ABSTRACT

A 59-year-old man underwent radical prostatectomy for adenocarcinoma in 2009. Because of the progression of PSA levels, a 68 Ga-PSMA PET/CT scan was performed in January 2020. A suspicious uptake was detected in the left cerebellar hemisphere, and there was no evidence of distant metastatic disease other than recurrent malignancy in the prostatectomy bed. MRI revealed a meningioma located in the left cerebellopontine angle. Although PSMA uptake of the lesion increased in the first imaging after hormone therapy, partial regression was noted after radiotherapy applied to this region.

Deregulation of miR-10b and miR-21 Correlate with Cancer Stem Cells Expansion through the Apoptotic Pathway in Prostate Cancer

BACKGROUND

MicroRNAs are small, non-coding RNA molecules that regulate important cellular processes such as tumorigenesis, cell proliferation, and apoptosis. Cancer stem cells are a subset of cells that control metastasis and cell proliferation. In this study, we focus on the roles of miR-10b, miR-21 and correlate with cancer stem cells through the apoptotic pathway in different stages of prostate cancer (PCa).

METHODS

In total, 45 patients, each group with Benign prostatic hyperplasia (BPH), localised PCa, and metastatic PCa, were recruited. MicroRNA and gene expression were estimated through quantitative polymerase chain reaction. Flow cytometry was used to characterise prostate cancer stem cells (PCSCs), estimate reactive oxygen species (ROS), apoptosis and chemiluminescent immunoassay was used to estimate interleukin 6 (IL-6), tumour necrosis factor (TNF-α), prostate-specific antigen (PSA), and testosterone.

RESULTS

The fold change mean expressions of miR-21, miR-10b, Cytochrome C, and B-cell lymphoma 2 (BCL-2) were significantly upregulated in localised and metastatic PCa compared with BPH. In contrast, the mean fold change expressions of Bcl-2-associated X protein (BAX), Caspase-3, Caspase-9, and Second mitochondria-derived activator of caspase (SMAC) were lower in localised and metastatic PCa compared to BPH. The levels of IL-6, TNF-α, ROS, PSA and testosterone also showed a significant increase while apoptosis was decreased in both localized PCa and metastatic PCa as compared with BPH. In bioinformatics analyses, we found a similar pattern of miRNAs and gene expression in PCa databases. Our study also found a high expression of CD44+/CD24- and CD44+/CD133+ in localised and metastatic PCa compared with BPH.

CONCLUSION

Our findings suggest miR-10b and miR-21 promote PCSCs and may target apoptotic genes involved in PCa pathogenesis; these miRNAs could be used as diagnosis biomarkers of PCa. In PCa pathogenesis and PCSCs regulation, the interaction between these two players is crucial and will help develop new PCa therapeutic targets.

Heterogeneity of [68Ga]Ga-PSMA-11 PET/CT in metastatic castration-resistant prostate cancer: genomic characteristics and association with abiraterone response

PURPOSE

The aim of this study was to evaluate the impact of the spatial heterogeneity of prostate-specific membrane antigen (PSMA) uptake on circulating tumor DNA (ctDNA) characteristics and the response rate to new hormonal agent (NHA) treatment.

METHODS

This retrospective study included 153 patients with metastatic castration-resistant prostate cancer (mCRPC) who underwent gallium-68 [68 Ga]Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT) and ctDNA sequencing with a less than 2-week interval. SUVhetero was defined as the variance of SUVmean for each PSMA-positive lesion. SUVmax-mean was obtained by subtracting the SUVmax by the SUVmean. Patients receiving abiraterone treatment after [68 Ga]Ga-PSMA-11 PET/CT and ctDNA sequencing and with complete follow-up record were included into prostate-specific antigen (PSA) response rate analysis. PSA response was defined as a reduction of greater than 50% from baseline.

RESULTS

The ctDNA detection rate was 65% (100/153). Higher SUVhetero value contributed to higher ctDNA% (Spearman's rho = 0.278, p < 0.002). A total of 60 patients were included in PSA response rate analysis. The median follow-up was 19.3 (IQR 16.2-23.2) months. Compare to patients with higher SUVhetero value, patients with NA SUVhetero had a higher PSA response rate (52% vs. 90%, p = 0.036). A higher SUVmax-mean value was strongly correlated with higher SUVhetero (Spearman's rho = 0.833, p < 0.0001). Patients with higher SUVmax-mean value also had a higher PSA response rate compared to patients with lower SUVmax-mean value (83.3% vs. 53.3%, p = 0.024). An external cohort confirmed baseline SUVmax-mean value was associated with enzalutamide treatment response rate. Patients with alterations in AR, DNA damage repair pathway, TP53, AR-associated pathway, cell cycle pathway, or WNT pathway had higher SUVmax-mean value compared to those without (p < 0.05).

CONCLUSION

Spatial heterogeneity of the PSMA uptake was associated with ctDNA characteristics and response rate to NHA treatment.

Landscape of prostate-specific membrane antigen heterogeneity and regulation in AR-positive and AR-negative metastatic prostate cancer

Tumor expression of prostate-specific membrane antigen (PSMA) is lost in 15-20% of men with castration-resistant prostate cancer (CRPC), yet the underlying mechanisms remain poorly defined. In androgen receptor (AR)-positive CRPC, we observed lower PSMA expression in liver lesions versus other sites, suggesting a role of the microenvironment in modulating PSMA. PSMA suppression was associated with promoter histone 3 lysine 27 methylation and higher levels of neutral amino acid transporters, correlating with 18F-fluciclovine uptake on positron emission tomography imaging. While PSMA is regulated by AR, we identified a subset of AR-negative CRPC with high PSMA. HOXB13 and AR co-occupancy at the PSMA enhancer and knockout models point to HOXB13 as an upstream regulator of PSMA in AR-positive and AR-negative prostate cancer. These data demonstrate how PSMA expression is differentially regulated across metastatic lesions and in the context of the AR, which may inform selection for PSMA-targeted therapies and development of complementary biomarkers.

Increased PSMA Expression in 177 Lu-PSMA-617 Scan in Metastatic Castrate-Resistant Prostate Cancer Patient Treated With PSMA Radioligand Therapy and Enzalutamide : A Potential Game-Changer

ABSTRACT

Androgen deprivation therapy plays an integral role in the treatment algorithm of advanced prostate cancer. Enzalutamide has shown great benefit in castrate-sensitive as well as resistant prostate cancer. Few studies have shown that enzalutamide can potentially increase the PSMA expression on 68 Ga-PSMA-11 PET/CT imaging in patients with metastatic castrate-resistant prostate cancer. We present an interesting case where addition of short course of enzalutamide resulted in increased localization of 177 Lu-PSMA-617 in metastatic lesions on posttherapy scan pointing to the added benefit of PSMA RLT.

Evaluation of PSMA target diagnostic PET tracers for therapeutic monitoring of [177Lu]ludotadipep of prostate cancer: Screening of PSMA target efficiency and biodistribution using [18F]DCFPyL and [68Ga]PSMA-11

We have compared the similarity of the in vivo distribution of the prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) imaging agents [¹⁸F]DCFPyL, [⁶⁸Ga]galdotadipep, and [⁶⁸Ga]PSMA-11. This study is designed for a further selection of a PSMA-targeted PET imaging agent for the therapeutic evaluation of [¹⁷⁷Lu]ludotadipep, our previously developed prostate-specific membrane antigen (PSMA)-targeted prostate cancer therapeutic radiopharmaceutical. In vitro cell uptake was performed to evaluate the affinity to PSMA using PSMA + PC3-PIP, and PSMA- PC3-flu was used for the study. MicroPET/CT 60 min dynamic imaging and biodistribution were performed at 1, 2, and 4 h after injection. Autoradiography and immunohistochemistry were performed to evaluate the PSMA + tumor target efficiency. In the microPET/CT image, [⁶⁸Ga]PSMA-11 showed the highest uptake in the kidney among all three compounds. [¹⁸F]DCFPyL and [⁶⁸Ga]PSMA-11 showed similar patterns of in vivo biodistribution and high tumor targeting efficiency, similar to those of[⁶⁸Ga]galdotadipep. All three agents showed high uptake in tumor tissue on autoradiography, and PSMA expression was confirmed by immunohistochemistry. Thus, [¹⁸F]DCFPyL or [⁶⁸Ga]PSMA-11 can be used as a PET imaging agent to monitor [¹⁷⁷Lu]ludotadipep therapy in prostate cancer patients.

Cytoreductive radical prostatectomy: who benefits from the surgical approach?

PURPOSE OF REVIEW

Local treatment in oligometastatic prostate cancer patients is associated with improved survival. Nevertheless, in term of surgery, cytoreductive radical prostatectomy has no level of evidence 1 and is an individual treatment approach. We reviewed the recent literature to highlight parameters for selecting patients for a surgical approach.

RECENT FINDINGS

Retrospective data on oncologic outcome for cytoreductive prostatectomy are confirmed. We identified several parameters that help to select patients for surgery. Patients with a favorable prostate-specific antigen (PSA) decline after androgen deprivation therapy (ADT) have excellent oncologic long-term control. Circulating tumor cells (CTC's) are frequently analyzed in more advanced prostate cancer. In case of C-reactive protein (CRP) at least a longer interval to develop castration resistant prostate cancer (CRPC) is shown in case of low CTC count at time of surgery. Nutrition status analyzed as the hemoglobin, albumin, lymphocyte, and platelet (HALP)-score is of significant value in demonstrating an effect of CRP.

SUMMARY

From retrospective findings we have several clinical and basic science parameters to select patients for CRP. PSA at the time of surgery is the most frequently analyzed one, whereas CTC and HALP-score are promising tools to select patients that need to be validated.

"Urethral-Sparing" Robotic Radical Prostatectomy: Critical Appraisal of the Safety of the Technique Based on the Histologic Characteristics of the Prostatic Urethra

BACKGROUND

The prostatic urethra (PU) is conventionally resected during robot-assisted radical prostatectomy (RALP). Recent studies demonstrated the feasibility of the extended PU preservation (EPUP).

AIMS

To describe the histologic features of the PU.

METHODS

The PU was evaluated using cystoprostatectomy and RALP specimens. Cases of PU infiltration by prostate cancer or distortion by benign hyperplastic nodules were excluded. The thickness of the chorion and distance between the urothelium and prostate glands were measured. Prostate-specific antigen expression in the PU epithelium was evaluated with immunohistochemistry. Descriptive statistics were used.

RESULTS

Six specimens of PU were examined. Histologically, the following layers of the PU were observed: (1) urothelium with basal membrane, (2) chorion, and (3) prostatic peri-urethral fibromuscular tissue. The chorion measures between 0.2 and 0.4 mm. There is not a distinct urethral muscle layer, but rather muscular fibers that originate near the prostatic stroma and are distributed around the PU. This muscular tissue appears to be mainly represented in the basal and apical urethra, but not in the middle urethra. The mean distance between the chorion and prostatic glands is 1.74 mm, with significant differences between base of the prostate, middle urethral portion, and apex (2.5 vs. 1.49 vs. 1.23 mm, respectively). PSA-expressing cells are abundant in the PU epithelium, coexisting with urothelial cells.

CONCLUSIONS

The exiguity of thickness of the PU chorion, short distance from glandular tissue, and coexistence of PSA-expressing cells in the epithelium raise important concerns about the oncologic safety of EPUP.

Glycoconjugate-Specific Developmental Changes in the Horse Vomeronasal Organ

The vomeronasal organ (VNO) is a tubular pheromone-sensing organ in which the lumen is covered with sensory and non-sensory epithelia. This study used immunohistochemistry and lectin histochemistry techniques to evaluate developmental changes, specifically of the glycoconjugate profile, in the horse VNO epithelium. Immunostaining analysis revealed PGP9.5 expression in some vomeronasal non-sensory epithelium (VNSE) cells and in the vomeronasal receptor cells of the vomeronasal sensory epithelium (VSE) in fetuses, young foals, and adult horses. Olfactory marker protein expression was exclusively localized in receptor cells of the VSE in fetuses, young foals, and adult horses and absent in VNSE. To identify the glycoconjugate type, lectin histochemistry was performed using 21 lectins. Semi-quantitative analysis revealed that the intensities of glycoconjugates labeled with WGA, DSL, LEL, and RCA120 were significantly higher in adult horse VSE than those in foal VSE, whereas the intensities of glycoconjugates labeled with LCA and PSA were significantly lower in adult horse VSE. The intensities of glycoconjugates labeled with s-WGA, WGA, BSL-II, DSL, LEL, STL, ConA, LCA, PSA, DBA, SBA, SJA, RCA120, jacalin, and ECL were significantly higher in adult horse VNSE than those in foal VNSE, whereas the intensity of glycoconjugates labeled with UEA-I was lower in adult horse VNSE. Histochemical analysis of each lectin revealed that various glycoconjugates in the VSE were present in the receptor, supporting, and basal cells of foals and adult horses. A similar pattern of lectin histochemistry was also observed in the VNSE of foals and adult horses. In conclusion, these results suggest that there is an increase in the level of N-acetylglucosamine (labeled by WGA, DSL, LEL) and galactose (labeled by RCA120) in horse VSE during postnatal development, implying that they may influence the function of VNO in adult horses.

Flare on [18F]PSMA-1007 PET/CT after short-term androgen deprivation therapy and its correlation to FDG uptake: possible marker of tumor aggressiveness in treatment-naïve metastatic prostate cancer patients

PURPOSE

Short-term androgen deprivation therapy (ADT) is known to increase heterogeneously prostate-specific membrane antigen (PSMA) expression. This phenomenon might indicate the potential of cancer lesions to respond to ADT. In this prospective study, we evaluated the flare on [18F]PSMA-1007 PET/CT after ADT in metastatic prostate cancer (PCa). Given that aggressive PCa tends to display FDG uptake, we particularly investigated whether the changes in PSMA uptake might correlate with glucose metabolism.

METHODS

Twenty-five men with newly diagnosed treatment-naïve metastatic PCa were enrolled in this prospective registered clinical trial. All the patients underwent [18F]PSMA-1007 PET/CT immediately before and 3-4 weeks after ADT initiation (degarelix). Before ADT, [18F]FDG PET/CT was also performed. Standardized uptake values (SUV)max of primary and metastatic lesions were calculated in all PET scans. Serum PSA and testosterone blood samples were collected before the two PSMA PET scans. The changes in PSMA uptake after ADT were represented as ΔSUVmax.

RESULTS

All the patients reached castration levels of testosterone at the time of the second [18F]PSMA-1007 PET/CT. Overall, 57 prostate, 314 lymph nodes (LN), and 406 bone lesions were analyzed. After ADT, 104 (26%) bone, 33 (11%) LN, and 6 (11%) prostate lesions showed an increase (≥ 20%) in PSMA uptake, with a median ΔSUVmax of + 50%, + 60%, and + 45%, respectively. Among the lesions detected at the baseline [18F]PSMA-1007 PET/CT, 63% bone and 46% LN were FDG-positive. In these metastases, a negative correlation was observed between the PSMA ΔSUVmax and FDG SUVmax (p < 0.0001). Moreover, a negative correlation between the ΔSUVmax and the decrease in serum PSA after ADT was noted (p < 0.0001).

CONCLUSIONS

A heterogeneous increase in PSMA uptake after ADT was detected, most evidently in bone metastases. We observed a negative correlation between the PSMA flare and the intensity of glucose uptake as well as the decrease of serum PSA, suggesting that lesions presenting with such flare might potentially be less aggressive.

TRIAL REGISTRATION

NCT03876912, registered 15 March 2019.

[Exosomes in the diagnosis of prostate cancer: Advances in studies]

In recent years, the incidence of PCa in China has been increasing year by year. Early diagnosis of the malignancy and monitoring of its progression are keys to the reduction of mortality. Currently, early diagnosis of PCa is mainly achieved by determining the level of PSA. Due to the insufficient specificity of PSA, definite diagnosis necessitates needle biopsy, which, as an invasive procedure, causes injury to the patients. Therefore biomarkers seem to be a significant option for the improvement of diagnostic accuracy. Exosomes are 30－150 nm extracellular vesicles secreted by various types of cells in normal and pathological conditions and exist stably in circumcision. Studies show that exosomes contain miRNAs and proteins critical to the progression and metastasis of PCa and have a great potential in the diagnosis of the malignancy. This review outlines the advances in the application of exosomes as novel biomarkers in the diagnosis of PCa.

3D-printed composite scaffold with gradient structure and programmed biomolecule delivery to guide stem cell behavior for osteochondral regeneration

The fabrication of osteochondral scaffolds with both structural and biochemical cues to regulate endogenous bone marrow-derived mesenchymal stem cells (BMSCs) behavior for cartilage and subchondral bone regeneration is still a challenge. To this end, a composite scaffold (BE-PSA) with gradient structure and programmed biomolecule delivery was prepared by fused deposition modeling (FDM) 3D printing and multi-material-based modification. The 3D-printed polycaprolactone (PCL) scaffold included upper pores of 200 μm for cartilage regeneration and lower pores of 400 μm for bone regeneration. For a sequential modulation of BMSCs behavior, fast-degrading sodium alginate (SA) hydrogel was used to deliver a burst release of E7 peptide to enhance BMSCs migration within 72 h, while a slowly-degrading silk fibroin (SF) porous matrix was used to provide a sustained release of B2A peptide to improve BMSCs dual-lineage differentiation lasting for >300 h, depending on the different degradation rates of SA hydrogel and SF matrix. The BE-PSA scaffold had good biocompatibility and could improve the migration and osteogenic/chondrogenic differentiation of BMSCs. Benefiting from the synergistic effects of spatial structures and programmed biomolecule delivery, the BE-PSA scaffold showed enhanced cartilage and subchondral bone regeneration in rabbit osteochondral defect model. This work not only provides a promising scaffold to guide BMSCs behavior for osteochondral regeneration but also offers a method for the fabrication of tissue engineering biomaterials based on the structural and biochemical modification.

Molecular Imaging of Neuroendocrine Prostate Cancer by Targeting Delta-Like Ligand 3

Treatment-induced neuroendocrine prostate cancer (NEPC) is a lethal subtype of castration-resistant prostate cancer. Using the 89Zr-labeled delta-like ligand 3 (DLL3) targeting antibody SC16 (89Zr-desferrioxamine [DFO]-SC16), we have developed a PET agent to noninvasively identify the presence of DLL3-positive NEPC lesions. Methods: Quantitative polymerase chain reaction and immunohistochemistry were used to compare relative levels of androgen receptor (AR)-regulated markers and the NEPC marker DLL3 in a panel of prostate cancer cell lines. PET imaging with 89Zr-DFO-SC16, 68Ga-PSMA-11, and 68Ga-DOTATATE was performed on H660 NEPC-xenografted male nude mice. 89Zr-DFO-SC16 uptake was corroborated by biodistribution studies. Results: In vitro studies demonstrated that H660 NEPC cells are positive for DLL3 and negative for AR, prostate-specific antigen, and prostate-specific membrane antigen (PSMA) at both the transcriptional and the translational levels. PET imaging and biodistribution studies confirmed that 89Zr-DFO-SC16 uptake is restricted to H660 xenografts, with background uptake in non-NEPC lesions (both AR-dependent and AR-independent). Conversely, H660 xenografts cannot be detected with imaging agents targeting PSMA (68Ga-PSMA-11) or somatostatin receptor subtype 2 (68Ga-DOTATATE). Conclusion: These studies demonstrated that H660 NEPC cells selectively express DLL3 on their cell surface and can be noninvasively identified with 89Zr-DFO-SC16.

Lipid nanoparticles to silence androgen receptor variants for prostate cancer therapy

Advanced-stage prostate cancer remains an incurable disease with poor patient prognosis. There is an unmet clinical need to target androgen receptor (AR) splice variants, which are key drivers of the disease. Some AR splice variants are insensitive to conventional hormonal or androgen deprivation therapy due to loss of the androgen ligand binding domain at the C-terminus and are constitutively active. Here we explore the use of RNA interference (RNAi) to target a universally conserved region of all AR splice variants for cleavage and degradation, thereby eliminating protein level resistance mechanisms. To this end, we tested five siRNA sequences designed against exon 1 of the AR mRNA and identified several that induced potent knockdown of full-length and truncated variant ARs in the 22Rv1 human prostate cancer cell line. We then demonstrated that 2'O methyl modification of the top candidate siRNA (siARv^m) enhanced AR and AR-V7 mRNA silencing potency in both 22Rv1 and LNCaP cells, which represent two different prostate cancer models. For downstream in vivo delivery, we formulated siARv^m-LNPs and functionally validated these in vitro by demonstrating knockdown of AR and AR-V7 mRNA in prostate cancer cells and loss of AR-mediated transcriptional activation of the PSA gene in both cell lines following treatment. We also observed that siARv^m-LNP induced cell viability inhibition was more potent compared to LNP containing siRNA targeting full-length AR mRNA (siARfl-LNP) in 22Rv1 cells as their proliferation is more dependent on AR splice variants than LNCaP and PC3 cells. The in vivo biodistribution of siARv^m-LNPs was determined in 22Rv1 tumor-bearing mice by incorporating ¹⁴C-radiolabelled DSPC in LNP formulation, and we observed a 4.4% ID/g tumor accumulation following intravenous administration. Finally, treatment of 22Rv1 tumor bearing mice with siARv^m-LNP resulted in significant tumor growth inhibition and survival benefit compared to siARfl-LNP or the siLUC-LNP control. To best of our knowledge, this is the first report demonstrating therapeutic effects of LNP-siRNA targeting AR splice variants in prostate cancer.

Antigen presenting cell response to polysaccharide A is characterized by the generation of anti-inflammatory macrophages

Polysaccharide A (PSA) is the immunodominant capsular carbohydrate from the gram negative commensal microbe Bacteroides fragilis that has shown remarkable potency in ameliorating many rodent models of inflammatory disease by eliciting downstream suppressive CD4+ T cells. PSA is composed of a zwitterionic repeating unit that allows it to be processed by antigen presenting cells (APCs) and presented by MHCII in a glycosylation-dependent manner. While previous work has uncovered much about the interactions between MHCII and PSA, as well as the downstream T cell response, little is known about how PSA affects the phenotype of MHCII+ APCs, including macrophages. Here, we utilized an unbiased systems approach consisting of RNAseq transcriptomics, high-throughput flow cytometry, Luminex analysis and targeted validation experiments to characterize the impact of PSA-mediated stimulation of splenic MHCII+ cells. The data revealed that PSA potently elicited the upregulation of an alternatively activated M2 macrophage transcriptomic and cell surface signature. Cell-type-specific validation experiments further demonstrated that PSA-exposed bone marrow-derived macrophages (BMDMs) induced cell surface and intracellular markers associated with M2 macrophages compared with conventional peptide ovalbumin (ova)-exposed BMDMs. In contrast to macrophages, we also found that CD11c+ dendritic cells (DCs) upregulated the pro-T cell activation costimulatory molecule CD86 following PSA stimulation. Consistent with the divergent BMDM and DC changes, PSA-exposed DCs elicited an antigen-experienced T cell phenotype in co-cultures, whereas macrophages did not. These findings collectively demonstrate that the PSA-induced immune response is characterized by both T cell stimulation via presentation by DCs, and a previously unrecognized anti-inflammatory polarization of macrophages.

Osteoarticular Involvement-Associated Biomarkers and Pathways in Psoriasis: The Shared Pathway With Ankylosing Spondylitis

Psoriatic arthritis (PsA) is a unique immune-mediated disease with cutaneous and osteoarticular involvement. However, only a few studies have explored the susceptibility of osteoarticular involvement in psoriasis (Ps) at the genetic level. This study investigated the biomarkers associated with osteoarticular participation and potential shared molecular mechanisms for PsA and ankylosing spondylitis (AS).

Kallikrein augments the anticoagulant function of the protein C system in thrombin generation

BACKGROUND

Genetics play a significant role in coagulation phenotype and venous thromboembolism risk. Resistance to the anticoagulant activated protein C (APC) is an established risk for thrombosis. Herein, we explored the genetic determinants of thrombin generation (TG) and thrombomodulin (TM)-modulated TG using plasma from the Human Functional Genomics Project.

METHODS

Calibrated TG was measured both in absence and presence of TM using tissue factor as trigger. Genetic determinants of TG parameters and protein C pathway function were assessed using genome-wide single-nucleotide polymorphism (SNP) genotyping. Plasma samples were supplemented with purified apolipoprotein A-IV, prekallikrein, or kallikrein to test their influence on the anticoagulant function of TM and APC in TG.

RESULTS

Thrombin generation data from 392 individuals were analyzed. Genotyping showed that the KLKB1 gene (top SNP: rs4241819) on chromosome 4 was associated with the normalized sensitivity ratio of endogenous thrombin potential to TM at genome-wide level (nETP-TMsr, P = 4.27 × 10-8 ). In vitro supplementation of kallikrein, but not prekallikrein or apolipoprotein A-IV, into plasma dose-dependently augmented the anticoagulant effect of TM and APC in TG. Variations of rs4241819 was not associated with the plasma concentration of prekallikrein. Association between rs4241819 and nETP-TMsr was absent when TG was measured in presence of a contact pathway inhibitor corn trypsin inhibitor.

CONCLUSIONS

Our results suggest that kallikrein plays a role in the regulation of the anticoagulant protein C pathway in TG, which may provide a novel mechanism for the previously observed association between the KLKB1 gene and venous thrombosis.

KLK3 in the Regulation of Angiogenesis-Tumorigenic or Not?

In this focused review, we address the role of the kallikrein-related peptidase 3 (KLK3), also known as prostate-specific antigen (PSA), in the regulation of angiogenesis. Early studies suggest that KLK3 is able to inhibit angiogenic processes, which is most likely dependent on its proteolytic activity. However, more recent evidence suggests that KLK3 may also have an opposite role, mediated by the ability of KLK3 to activate the (lymph)angiogenic vascular endothelial growth factors VEGF-C and VEGF-D, further discussed in the review.

Characteristics of α2,3-sialyl N-glycosylated PSA as a biomarker for clinically significant prostate cancer in men with elevated PSA level

BACKGROUND

The presence of glycosylated isoforms of prostate-specific antigen (PSA) in prostate cancer (PC) cells is a potential marker of their aggressiveness. We characterized the origin of α2,3-sialylated prostate-specific antigen (S23PSA) by tissue-based sialylation-related gene expression and studied the performance of S23PSA density (S23PSAD) alone and in combination with multiparametric magnetic resonance imaging (MRI) for the detection of clinically significant prostate cancer in men with elevated PSA.

METHODS

Tissue-based quantification of S23PSA and sialyltransferase and sialidase gene expression was evaluated in 71 radical prostatectomy specimens. The diagnostic performance of S23PSAD was studied in 1099 men retrospectively enrolled in a multicenter systematic biopsy (SBx) cohort. We correlated the S23PSAD with Prostate Imaging Reporting and Data System (PI-RADS) scores in 98 men prospectively enrolled in a single-center MRI-targeted biopsy (MRI-TBx) cohort. The primary outcome was the PC-diagnostic performance of the S23PSAD, the secondary outcome was the avoidable biopsy rate of S23PSAD combined with DRE and total PSA (tPSA), and with or without PI-RADS.

RESULTS

S23PSA was significantly higher in Gleason pattern 4 and 5 compared with benign prostate tissue. In the retrospective cohort, the performance of S23PSAD for detecting PC was superior to tPSA or PSA density (PSAD) (AUC: 0.7758 vs. 0.6360 and 0.7509, respectively). In the prospective cohort, S23PSAD was superior to tPSA, PSAD, and PI-RADS (AUC: 0.7725 vs. 0.5901, 0.7439 and 0.7305, respectively), and S23PSAD + PI-RADS + DRE + tPSA was superior to DRE + tPSA+PI-RADS with avoidance rate of MRI-TBx (13% vs. 1%) at 30% risk threshold.

CONCLUSIONS

The diagnostic performance of S23PSAD was superior to conventional strategies but comparable to mpMRI.

Synthesis and Preliminary Biological Assessment of Carborane-Loaded Theranostic Nanoparticles to Target Prostate-Specific Membrane Antigen

Boron neutron capture therapy (BNCT) is an encouraging therapeutic modality for cancer treatment. Prostate-specific membrane antigen (PSMA) is a cell membrane protein that is abundantly overexpressed in prostate cancer and can be targeted with radioligand therapies to stimulate clinical responses in patients. In principle, a spatially targeted neutron beam together with specifically targeted PSMA ligands could enable prostate cancer-targeted BNCT. Thus, we developed and tested PSMA-targeted poly(lactide-co-glycolide)-block-poly(ethylene glycol) (PLGA-b-PEG) nanoparticles (NPs) loaded with carborane and tethered to the radiometal chelator deferoxamine B (DFB) for simultaneous positron emission tomography (PET) imaging and selective delivery of boron to prostate cancer. Monomeric PLGA-b-PEGs were covalently functionalized with either DFB or the PSMA ligand ACUPA. Different nanoparticle formulations were generated by nanoemulsification of the corresponding unmodified and DFB- or ACUPA-modified monomers in varying percent fractions. The nanoparticles were efficiently labeled with ⁸⁹Zr and were subjected to in vitro and in vivo evaluation. The optimized DFB(25)ACUPA(75) NPs exhibited strong in vitro binding to PSMA in direct binding and competition radioligand binding assays in PSMA(+) PC3-Pip cells. [⁸⁹Zr]DFB(25) NPs and [⁸⁹Zr]DFB(25)ACUPA(75) NPs were injected to mice with bilateral PSMA(-) PC3-Flu and PSMA(+) PC3-Pip dual xenografts. The NPs demonstrated twofold superior accumulation in PC3-Pip tumors to that of PC3-Flu tumors with a tumor/blood ratio of 25; however, no substantial effect of the ACUPA ligands was detected. Moreover, fast release of carborane from the NPs was observed, resulting in a low boron delivery to tumors in vivo. In summary, these data demonstrate the synthesis, characterization, and initial biological assessment of PSMA-targeted, carborane-loaded PLGA-b-PEG nanoparticles and establish the foundation for future efforts to enable their best use in vivo.

Secreted indicators of androgen receptor activity in breast cancer pre-clinical models

PURPOSE

Accumulating evidence has attracted attention to the androgen receptor (AR) as a biomarker and therapeutic target in breast cancer. We hypothesized that AR activity within the tumor has clinical implications and investigated whether androgen responsive serum factors might serve as a minimally invasive indicator of tumor AR activity.

METHODS

Based on a comprehensive gene expression analysis of an AR-positive, triple negative breast cancer patient-derived xenograft (PDX) model, 163 dihydrotestosterone (DHT)-responsive genes were defined as an androgen responsive gene set. Among them, we focused on genes that were DHT-responsive that encode secreted proteins, namely KLK3, AZGP1 and PIP, that encode the secreted factors prostate specific antigen (PSA), zinc-alpha-2-glycoprotein (ZAG) and prolactin induced protein (PIP), respectively. Using AR-positive breast cancer cell lines representing all breast cancer subtypes, expression of candidate factors was assessed in response to agonist DHT and antagonist enzalutamide. Gene set enrichment analysis (GSEA) was performed on publically available gene expression datasets from breast cancer patients to analyze the relationship between genes encoding the secreted factors and other androgen responsive gene sets in each breast cancer subtype.

RESULTS

Anti-androgen treatment decreased proliferation in all cell lines tested representing various tumor subtypes. Expression of the secreted factors was regulated by AR activation in the majority of breast cancer cell lines. In GSEA, the candidate genes were positively correlated with an androgen responsive gene set across breast cancer subtypes.

CONCLUSION

KLK3, AZGP1 and PIP are AR regulated and reflect tumor AR activity. Further investigations are needed to examine the potential efficacy of these factors as serum biomarkers.

Proteomic characterization of primary and metastatic prostate cancer reveals reduced proteinase activity in aggressive tumors

Prostate cancer (PCa) is a heterogeneous group of tumors with variable clinical courses. In order to improve patient outcomes, it is critical to clinically separate aggressive PCa (AG) from non-aggressive PCa (NAG). Although recent genomic studies have identified a spectrum of molecular abnormalities associated with aggressive PCa, it is still challenging to separate AG from NAG. To better understand the functional consequences of PCa progression and the unique features of the AG subtype, we studied the proteomic signatures of primary AG, NAG and metastatic PCa. 39 PCa and 10 benign prostate controls in a discovery cohort and 57 PCa in a validation cohort were analyzed using a data-independent acquisition (DIA) SWATH-MS platform. Proteins with the highest variances (top 500 proteins) were annotated for the pathway enrichment analysis. Functional analysis of differentially expressed proteins in NAG and AG was performed. Data was further validated using a validation cohort; and was also compared with a TCGA mRNA expression dataset and confirmed by immunohistochemistry (IHC) using PCa tissue microarray (TMA). 4,415 proteins were identified in the tumor and benign control tissues, including 158 up-regulated and 116 down-regulated proteins in AG tumors. A functional analysis of tumor-associated proteins revealed reduced expressions of several proteinases, including dipeptidyl peptidase 4 (DPP4), carboxypeptidase E (CPE) and prostate specific antigen (KLK3) in AG and metastatic PCa. A targeted analysis further identified that the reduced expression of DPP4 was associated with the accumulation of DPP4 substrates and the reduced ratio of DPP4 cleaved peptide to intact substrate peptide. Findings were further validated using an independently-collected tumor cohort, correlated with a TCGA mRNA dataset, and confirmed by immunohistochemical stains of PCa tumor microarray (TMA). Our study is the first large-scale proteomics analysis of PCa tissue using a DIA SWATH-MS platform. It provides not only an interrogative proteomic signature of PCa subtypes, but also indicates the critical roles played by certain proteinases during tumor progression. The spectrum map and protein profile generated in the study can be used to investigate potential biological mechanisms involved in PCa and for the development of a clinical assay to distinguish aggressive from indolent PCa.

MiR-205-driven downregulation of cholesterol biosynthesis through SQLE-inhibition identifies therapeutic vulnerability in aggressive prostate cancer

Prostate cancer (PCa) shows strong dependence on the androgen receptor (AR) pathway. Here, we show that squalene epoxidase (SQLE), an enzyme of the cholesterol biosynthesis pathway, is overexpressed in advanced PCa and its expression correlates with poor survival. SQLE expression is controlled by micro-RNA 205 (miR-205), which is significantly downregulated in advanced PCa. Restoration of miR-205 expression or competitive inhibition of SQLE led to inhibition of de novo cholesterol biosynthesis. Furthermore, SQLE was essential for proliferation of AR-positive PCa cell lines, including abiraterone or enzalutamide resistant derivatives, and blocked transactivation of the AR pathway. Inhibition of SQLE with the FDA approved antifungal drug terbinafine also efficiently blocked orthotopic tumour growth in mice. Finally, terbinafine reduced levels of prostate specific antigen (PSA) in three out of four late-stage PCa patients. These results highlight SQLE as a therapeutic target for the treatment of advanced PCa.

KAT2A-mediated AR translocation into nucleus promotes abiraterone-resistance in castration-resistant prostate cancer

Abiraterone, a novel androgen synthesis inhibitor, has been approved for castration-resistant prostate cancer (CRPC) treatment. However, most patients eventually acquire resistance to this agent, and the underlying mechanisms related to this resistance remain largely unelucidated. Lysine acetyltransferase 2 A (KAT2A) has been reported to enhance transcriptional activity for certain histone or non-histone proteins through the acetylation and post-translational modification of the androgen receptor (AR). Therefore, we hypothesised that KAT2A might play a critical role in the resistance of prostate tumours to hormonal treatment. In this study, we found that KAT2A expression was increased in abiraterone-resistant prostate cancer C4-2 cells (C4-2-AbiR). Consistently, elevated expression of KAT2A was observed in patients with prostate cancer exhibiting high-grade disease or biochemical recurrence following radical prostatectomy, as well as in those with poor clinical survival outcomes. Moreover, KAT2A knockdown partially re-sensitised C4-2-AbiR cells to abiraterone, whereas KAT2A overexpression promoted abiraterone resistance in parental C4-2 cells. Consistent with this finding, KAT2A knockdown rescued abiraterone sensitivity and inhibited the proliferation of C4-2-AbiR cells in a mouse model. Mechanistically, KAT2A directly acetylated the hinge region of the AR, and induced AR translocation from the cytoplasm to the nucleus, resulting in increased transcriptional activity of the AR-targeted gene prostate specific antigen (PSA) leading to resistance to the inhibitory effect of abiraterone on proliferation. Taken together, our findings demonstrate a substantial role for KAT2A in the regulation of post-translational modifications in AR affecting CRPC development, suggesting that targeting KAT2A might be a potential strategy for CRPC treatment.

Androgens alter the heterogeneity of small extracellular vesicles and the small RNA cargo in prostate cancer

Proliferation and survival of prostate cancer cells are driven by the androgen receptor (AR) upon binding to androgen steroid hormones. Manipulating the AR signalling axis is the focus for prostate cancer therapy; thus, it is crucial to understand the role of androgens and AR on extracellular vesicle (EV) secretion and cargo. In this study, we report that plasma-derived circulating vesicles consisting of CD9 and double-positive for CD9 and Prostate Specific Membrane Antigen (PSMA) are increased in patients with advanced metastatic prostate cancer, whereas double positives for CD9 and CD63 small extracellular vesicles (S-EVs) are significantly higher in patients with localised prostate cancer. Androgen manipulation by dihydrotestosterone (DHT) and the clinical antagonist enzalutamide (ENZ) altered the heterogeneity and size of CD9 positive S-EVs in AR expressing prostate cancer cells, while assessment of the total number and protein cargo of total S-EVs was unaltered across different treatment groups. Furthermore, hormone stimulation caused strong and specific effects on the small RNA cargo of S-EVs. A total of 543 small RNAs were found to be regulated by androgens including miR-19-3p and miR-361-5p. Analysis of S-EVs heterogeneity and small RNA cargo may provide clinical utility for prostate cancer and be informative to understand further the mechanism of resistance to androgen targeted therapy in castration-resistant prostate cancer.

Clinical parameters and nomograms for predicting lymph node metastasis detected with 68 Ga-PSMA-PET/CT in prostate cancer patients candidate to definitive radiotherapy

BACKGROUND

Defining the extent of disease spread with imaging modalities is crucial for therapeutic decision-making and definition of treatment. This study aimed to investigate whether clinical parameters and nomograms predict prostate-specific membrane antigen (PSMA)-positive lymph nodes in treatment-naïve nonmetastatic prostate cancer (PC) patients.

MATERIALS AND METHODS

The clinical data of 443 PC patients (83.3% high-risk and 16.7% intermediate-risk) were retrospectively analyzed. Receiver operating characteristic (ROC) curves with areas under the curve (AUC) were generated to evaluate the accuracy of clinical parameters (prostate-specific antigen [PSA], T stage, Gleason score [GS], International Society of Urological Pathology [ISUP] grade) and nomograms (Roach formula [RF], Yale formula [YF], and a new formula [NF]) in predicting lymph node metastasis. The AUCs of the various parameters and clinical nomograms were compared using ROC and precision-recall (PR) curves.

RESULTS

A total of 288 lymph node metastases were identified in 121 patients (27.3%) using ⁶⁸ Ga-PSMA-11-positron emission tomography (PET)/computed tomography (CT). Most PSMA-avid lymph node metastases occurred in external or internal iliac lymph nodes (142; 49.3%). Clinical T stage, PSA, GS, and ISUP grade were significantly associated with PSMA-positive lymph nodes according to univariate logistic regression analysis. The PSMA-positive lymph nodes were more frequently detected in patients with PSA >20 ng/ml, GS ≥7 or high risk disease compared to their counterparts. The clinical T stage, serum PSA level, GS, and ISUP grade showed similar accuracy in predicting PSMA-positive metastasis, with AUC values ranging from 0.675 to 0.704. The median risks for PSMA-positive lymph nodes according to the RF, YF, and NF were 31.3% (range: 12.3%-100%), 22.3% (range: 4.7%-100%), and 40.5% (range: 12.3%-100%), respectively. The AUC values generated from ROC and PR curve analyses were similar for all clinical nomograms, although the RF and YF had higher accuracy compared to NF.

CONCLUSION

The clinical T stage, PSA, GS, and ISUP grade are independent predictors of PSMA-positive lymph nodes. The RF and YF can be used to identify patients who can benefit from ⁶⁸ Ga-PSMA-11 PET/CT for the detection of lymph node metastasis. Together with nomograms, ⁶⁸ Ga-PSMA-11 PET/CT images help to localize PSMA-positive lymph node metastases and can thus assist in surgery and radiotherapy planning.

Skene's Gland Derivatives in the Female Genital Tract and Cervical Adenoid Basal Carcinoma are Consistently Positive With Prostatic Marker NKX3.1

Cervical ectopic prostatic tissue and vaginal tubulosquamous polyp are rare lesions which exhibit variable, and often focal, immunohistochemical expression with traditional prostatic markers [prostate-specific antigen and prostatic acid phosphatase (PSAP)]. These lesions are thought to arise from periurethral Skene's glands, the female equivalent of prostatic glands in the male. Adenoid basal carcinoma is a rare and indolent cervical neoplasm. Expression of the prostatic marker NKX3.1 in ectopic prostatic tissue and tubulosquamous polyp has been reported but no studies have examined immunoreactivity with this marker in adenoid basal carcinoma. We stained 19 cases [adenoid basal carcinoma (n=6), cervical ectopic prostatic tissue (n=11), and vaginal tubulosquamous polyp (n=3); 1 case contained both adenoid basal carcinoma and ectopic prostatic tissue] with NKX3.1. In all cases, the glandular component of these lesions exhibited diffuse nuclear immunoreactivity while normal endocervical glands were negative. Prostate-specific antigen was positive in 4 of 9 and 0 of 3 cases of ectopic prostatic tissue and tubulosquamous polyp, respectively, while PSAP was positive in 3 of 4 and 2 of 2 cases of ectopic prostatic tissue and tubulosquamous polyp respectively; 3 of 5 cases of adenoid basal carcinoma tested were focally positive with PSAP and all 5 were negative with prostate-specific antigen. While the specificity of NKX3.1 should be investigated in future studies, positivity with this marker may be useful in diagnosing these uncommon lesions. NKX3.1 appears a more sensitive marker of ectopic prostatic tissue and tubulosquamous polyp than traditional prostatic markers and positive staining provides further support that these lesions exhibit "prostatic" differentiation and are of Skene's gland origin. NKX3.1 and PSAP positivity in adenoid basal carcinoma raises the possibility of an association with benign glandular lesions exhibiting prostatic differentiation and we critically discuss the possible association.

Protein Phosphatase 4 Promotes Hepatocyte Lipoapoptosis by Regulating RAC1/MLK3/JNK Pathway

Lipotoxicity-induced apoptosis, also referred to as lipoapoptosis, is one of the important initial factors promoting the progression from hepatosteatosis to nonalcoholic steatohepatitis (NASH). Saturated free fatty acids (SFAs), which are increased significantly in NASH, are directly hepatotoxic which induce hepatocyte lipoapoptosis. Previously, we reported that protein phosphatase 4 (PP4) was a novel regulator of hepatic insulin resistance and lipid metabolism, but its role in hepatic lipoapoptosis remains unexplored. In this study, we found out that PP4 was upregulated in the livers of western diet-fed-induced NASH mice and SFA-treated murine primary hepatocytes and HepG2 cells. In addition, we found for the first time that suppression of PP4 decreased SFA-induced JNK activation and expression of key modulators of hepatocyte lipoapoptosis including p53-upregulated modulator of apoptosis (PUMA) and Bcl-2-interacting mediator (Bim) and reduced hepatocyte lipoapoptosis level as well both in vitro and in vivo. Further study revealed that PP4 induced JNK activation and lipoapoptosis-related protein expression by regulating the RAC1/MLK3 pathway instead of the PERK/CHOP pathway. The effects of palmitate-treated and PP4-induced lipoapoptosis pathway activation were largely abolished by RAC1 inhibition. Moreover, we identified that PP4 interacted with RAC1 and regulated GTPase activity of RAC1. In conclusion, these results demonstrated that PP4 was a novel regulator of hepatocyte lipoapoptosis and mediated hepatocyte lipoapoptosis by regulating the RAC1/MLK3/JNK signaling pathway. Our finding provided new insights into the mechanisms of this process.

Psoralea corylifolia L. extract ameliorates benign prostatic hyperplasia by regulating prostate cell proliferation and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Psoralea corylifolia L. seed (PCL), commonly known as "Poguzhi" or "BuguZhi", has been widely used to treat kidney yang deficiency in traditional Chinese medicine (TCM) where tonifying the yang deficiency is a representative understanding for treatment of hormonal deficiency disorders such as enuresis, oliguria, and prostatic diseases. Although PCL has been commonly used to treat problems of the urinary system, its efficacy against benign prostatic hyperplasia (BPH) has not yet been reported.

AIM OF THE STUDY

In the present study, we aimed to assess the in vitro and in vivo efficacy of PCL against BPH, a condition which negatively impacts quality of life in men.

MATERIALS AND METHODS

Normal human prostate cell lines, RWPE-1 and WPMY-1 cells, were stimulated with 10 nM dihydrotestosterone (DHT) to establish an in vitro BPH model. Subsequently, cells were treated with 100 or 200 μg/ml PCL, which inhibited cell proliferation without cytotoxicity, to evaluate the anti-BPH effect of PCL. Eight-week-old male Wistar rats were castrated, except for those in the control group (Con), and BPH was induced by subcutaneous injection of 10 mg/kg testosterone propionate (TP). Concurrent with daily TP injections, 5 mg/kg of finasteride (Fina) and 50 or 100 mg/kg PCL were orally administrated daily for four weeks, excluding the weekends.

RESULTS

In DHT-stimulated RWPE-1 and WPMY-1 cells, expression of androgen receptor (AR) androgen signaling-related markers such as 5α-reductase 2 (5AR2), AR, and prostate-specific antigen (PSA) was upregulated, whereas 100 or 200 μg/ml of PCL treatment downregulated these markers. Furthermore, PCL significantly reduced the mRNA expression of anti-apoptotic genes and increased the mRNA expression of pro-apoptotic gene. In vivo, administration of PCL reduced prostate size and weight in TP-induced BPH rats. Moreover, histological alterations in epithelium thickness were significantly restored by the administration of PCL. Immunohistochemical analysis revealed increased expression of AR and proliferating cell nuclear antigen (PCNA) in TP-induced BPH prostates; these changes were suppressed by administration of 50 or 100 mg/kg PCL.

CONCLUSIONS

We demonstrated the effect of PCL against BPH, mediated by the regulation of prostate cell proliferation and apoptosis, in DHT-stimulated normal human prostate cell lines and TP-induced BPH rats. These findings suggest that PCL could be a potential therapeutic agent against BPH.

Recent Semen Exposure Impacts the Cytokine Response and Bacterial Vaginosis in Women

Background

The presence of semen in the vagina from unprotected sex may influence the immune and microbial environment of the female genital tract. Inflammatory cytokine concentrations and BV-associated bacteria in female genital secretions may influence HIV risk, although the effect of recent sexual intercourse on incident BV and the cytokine milieu of cervicovaginal secretions has rarely been measured in previous studies. Here, we investigated the extent to which partner semen impacts the cytokine response and incident BV.

Methods

At baseline, we assessed the recency of semen exposure in menstrual cup supernatants by quantifying prostate specific antigen (PSA) levels using ELISA in 248 HIV-uninfected women at high risk for HIV infection. Luminex was used to measure 48 cytokines in menstrual cup supernatants and vaginal swabs to diagnose BV by Nugent score. Point-of-care screening for Chlamydia trachomatis and Neisseria gonorrhoeae was conducted using GeneXpert while OSOM was used for Trichomonas vaginalis detection. Multivariable models, adjusted for age, sexually transmitted infections, BV, current contraception use and condom use, were used to assess the impact of semen exposure on biomarkers of inflammation and BV.

Results

Presence of PSA, indicating recent semen exposure within 48 hours prior to sampling, was observed in menstrual cup supernatants of 17% (43/248) of women. Of these women, 70% (30/43) had self-reported condom use at their last sex act and 84% (36/43) had BV (Nugent score >7). PSA presence was significantly associated with prevalent BV (Relative Risk (RR), 2.609; 95% Confidence Interval (CI), 1.104 - 6.165; p = 0.029). Furthermore, women with detectable PSA had high median concentrations of macrophage inflammatory protein- beta (MIP-1α, p=0.047) and low median concentration of the stem cell growth factor beta (SCGF-β, p=0.038) compared to those without PSA.

Conclusion

A degree of discordance between self-reports of consistent condom use and PSA positivity was observed. There was also evidence of a relationship between recent semen exposure, BV prevalence and altered cytokine concentrations. These findings suggest that PSA, as a semen biomarker, should be taken into consideration when investigating biological markers in the female genital tract and self-reported condom use in studies on reproductive and sexual health.

225 Ac-PSMA-617-targeted alpha therapy for the treatment of metastatic castration-resistant prostate cancer: A systematic review and meta-analysis

BACKGROUND

The aim of this systematic review and meta-analysis was to present an overview of the role of ²²⁵ Ac-PSMA (prostate-specific membrane antigen)-targeted alpha therapy (TAT) as a salvage treatment option in metastatic castration-resistant prostate cancer.

METHODS

A systematic literature review was performed in databases such as Medline, Embase, PubMed, Cochrane Central Register of Controlled Clinical Trials, and the website; www.ClinicalTrials.gov until December 2020. The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. All original articles, including retrospective, prospective, hand-searched articles, and clinical trials, were searched, and appropriate data were included for the analysis. The study's primary endpoint assessed therapeutic efficacy by biochemical response assessment criteria (any prostate-specific antigen [PSA] decline and >50% PSA decline from the baseline) after ²²⁵ Ac-PSMA-TAT. The secondary endpoints included assessing overall survival (OS), progression-free survival (PFS), molecular response, and therapy-related adverse events across all the studies. The values were expressed as pooled proportions and demonstrated graphically by forest plots using the random-effects model.

RESULTS

After the data extraction and filtration process, a total of three publications, including 141 patients, were included for the final analysis. The pooled proportion of patients demonstrating any PSA decline and greater than 50% PSA decline were 83% (95% confidence interval [CI]: 77%-89%) and 59% (95% CI: 42%-76%), respectively. The pooled proportions for OS was 81% (95% CI: 74%-89%). The pooled proportion of patients who have shown complete molecular response are 17% (95% CI: 5%-29%). The median PFS was 12 months (interquartile range: 8.2-14.4 months). Across the studies, the most common side effects from ²²⁵ Ac-PSMA-617 TAT were xerostomia/dry mouth, which pertained to Gr I-II in 63.1% (89 of 141), followed by fatigue in 44.5% (45 of 101) of patients. Grade I-II and III anemia was noted in 48.5% (49 of 101) and 6% (6 of 101), respectively. Grade III leukopenia and thrombocytopenia were negligible: 0.9% (1 of 101) and 0.9% (1 of 101), respectively. Similarly, grade III nephrotoxicity was also observed only in 5 of 101 (5%) patients.

CONCLUSION

Treatment with ²²⁵ Ac-PSMA-617 TAT demonstrated biochemical response, improved survival, caused low treatment-related toxicity proving a promising salvage treatment option in mCRPC patients.

Treatment results of radiotherapy to both the prostate and metastatic sites in patients with bone metastatic prostate cancer

Although systemic therapy is the standard treatment for metastatic prostate cancer, a randomized controlled trial showed radiotherapy to the prostate improved overall survival of metastatic prostate cancer patients with the low metastatic burden. Additionally, a randomized phase II trial showed that metastasis-directed therapy for oligo-recurrent prostate cancer improved androgen-deprivation therapy (ADT)-free survival. Therefore, administering radiotherapy to both prostate and metastatic regions might result in better outcomes. Thus, we report the treatment results of radiotherapy to both prostate and metastatic regions. Our institutional database was searched for patients who received radiotherapy to the prostate and metastatic regions. We summarized patient characteristics and treatment efficacy and performed statistical analysis to find possible prognostic factors. A total of 35 patients were included in this study. The median age was 66 years, and the median initial prostate-specific antigen (PSA) level was 32 ng/ml. The Gleason score was 7 in 10 patients, 8 in 13 patients, and 9 in 12 patients. The median radiotherapy dose was 72 Gy to the prostate and 50 Gy to the metastatic bone region. The 8-year overall survival, cause-specific survival, progression-free survival, and freedom from biochemical failure rate were 81, 85, 53, and 57%. Among the 35 patients, 12 were disease-free even after ADT was discontinued. In selected patients with metastatic prostate cancer, ADT and radiotherapy to the prostate and metastatic sites were effective. Patients with good response to ADT may benefit from radiotherapy to both prostate and metastatic regions.

Progress in Targeted Alpha-Particle-Emitting Radiopharmaceuticals as Treatments for Prostate Cancer Patients with Bone Metastases

Bone metastasis remains a major cause of death in cancer patients, and current therapies for bone metastatic disease are mainly palliative. Bone metastases arise after cancer cells have colonized the bone and co-opted the normal bone remodeling process. In addition to bone-targeted therapies (e.g., bisphosphonate and denosumab), hormone therapy, chemotherapy, external beam radiation therapy, and surgical intervention, attempts have been made to use systemic radiotherapy as a means of delivering cytocidal radiation to every bone metastatic lesion. Initially, several bone-seeking beta-minus-particle-emitting radiopharmaceuticals were incorporated into the treatment for bone metastases, but they failed to extend the overall survival in patients. However, recent clinical trials indicate that radium-223 dichloride (223RaCl2), an alpha-particle-emitting radiopharmaceutical, improves the overall survival of prostate cancer patients with bone metastases. This success has renewed interest in targeted alpha-particle therapy development for visceral and bone metastasis. This review will discuss (i) the biology of bone metastasis, especially focusing on the vicious cycle of bone metastasis, (ii) how bone remodeling has been exploited to administer systemic radiotherapies, and (iii) targeted radiotherapy development and progress in the development of targeted alpha-particle therapy for the treatment of prostate cancer bone metastasis.

Systematic and MRI-Cognitive Targeted Transperineal Prostate Biopsy Accuracy in Detecting Clinically Significant Prostate Cancer after Previous Negative Biopsy and Persisting Suspicion of Malignancy

Background and objectives: Overdiagnosis, overtreatment, and the need for repeated procedures caused by transrectal ultrasound guided prostate biopsies and their related complications places a heavy burden on healthcare systems. This was a prospective cohort validating study to access the clinical accuracy of systematic and MRI-cognitive targeted transperineal prostate biopsies in detecting clinically significant prostate cancer after a previous negative biopsy and persistent suspicion of malignancy. The primary goal was to assess the ability of multiparametric magnetic resonance imaging (mpMRI) to detect clinically significant prostate cancer with an additional goal to assess the diagnostic value of systematic and MRI-cognitive transperineal biopsies. Materials and Methods: In total, 200 patients were enrolled who had rising serum prostate specific antigen (PSA) levels for at least 4 months after a previous negative transrectal ultrasound (TRUS) biopsy. All eligible men underwent 1.5T prostate mpMRI, reported using the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2), followed by a 20-region transperineal prostate systematic biopsy and additional targeted biopsies. Results: Systematic 20-core transperineal prostate biopsies (TPBs) were performed for 38 (19%) patients. Systemic 20-core TPB with additional cognitive targeted biopsies were performed for 162 (81%) patients. Clinically significant prostate cancer (csPC) was detected for 31 (15.5%) patients, of which 20 (64.5%) cases of csPC were detected by systematic biopsy, eight (25.8%) cases were detected by targeted biopsy, and three (9.7%) both by systematic and targeted biopsies. Conclusions: Cognitive mpMRI guided transperineal target biopsies increase the detection rate of clinically significant prostate cancer after a previously negative biopsy. However, in a repeat prostate biopsy setting, we recommend applying a cognitive targeted biopsy with the addition of a systematic biopsy.