Prostate-specific Antigen Expression Research Articles

Effect of IgG Fc-fusion and KDEL-ER retention signal on prostate-specific antigen expression in plant and its immune in mice

Effect of IgG Fc-fusion and KDEL-ER retention signal on prostate-specific antigen expression in plant and its immune in mice

The Importance of Prostate-Specific Membrane Antigen Expression in Salivary Gland Tumors.

Prostate-specific membrane antigen (PSMA) is a cell membrane protein expressed by prostate tissues. It is not prostate specific and is also expressed by some non-prostatic solid neoplasms. Our study aimed to investigate the potential role of PSMA in salivary gland tumors. The present study was designed to retrospectively analyze our cases that presented with salivary gland tumors. The files of 105 patients were reviewed and their paraffin embedded blocks were retrieved from the pathology department. Immunohistochemical examination and staining were done using PSMA antibody. Tumor tissue PSMA immunohistochemical staining was scored semi-quantitatively with the modified quartile approach. Negative staining was scored 0, >0% and ≤25% tissue expression was considered weak (score 1), >25% and ≤50% tissue expression was considered mild (score 2), >50% and ≤75% tissue expression was considered moderate (score 3), and >75% tissue expression was considered strong (score 4). Eighty-eight patients (55 males, 33 females) were included in the study. Forty-eight patients had pleomorphic adenoma (PA), 35 had Warthin's tumor (WT), two had mucoepidermoid carcinoma, two had adenoid cystic carcinoma, and one had squamous cell carcinoma. There was statistically significant difference in terms of PSMA expression between PA and WT (p=0.003). PSMA expression was high in PA and absent in WT. PSMA is a potential source of inspiration for future studies on the development of novel diagnostic and theranostic investigations of salivary gland tumors. Prospective studies targeting intratumoral PSMA in salivary gland tumors should be planned.

Integrative molecular analyses define correlates of high B7-H3 expression in metastatic castrate-resistant prostate cancer

B7-H3 (CD276) is an immune checkpoint overexpressed in prostate cancer with minimal expression in normal tissues and associated with poor prognosis, making it an excellent therapy target. We interrogated B7-H3 expression and its regulation in metastatic castration-resistant prostate cancer (mCRPC). We found greater expression of B7-H3 transcript relative to other immunotherapy targets (CTLA-4, PD-L1/2), including in tumors that lacked expression of prostate-specific membrane antigen (PSMA). Enzalutamide-resistant mCRPC cells demonstrated increased amounts of B7-H3, and this was associated with resistance signaling pathways. Using a machine-learning algorithm, the gene network of B7-H3 was strongly correlated with androgen receptor (AR) and AR co-factor (HOXB13, FOXA1) networks. In mCRPC samples, the B7-H3 promoter and distal enhancer regions exhibited enhanced transcriptional activity and were directly bound by AR and its co-factors. Altogether, our study characterizes molecular profiles and epigenetic regulation of B7-H3-expressing mCRPC tumors, which informs optimal precision-oncology approaches for mCRPC patients.

Sargassum horneri Extract Alleviates Testosterone-Induced Benign Prostatic Hyperplasia In vitro and In vivo

ABSTRACT Sargassum horneri (Turner) C. Agardh (S. horneri) is brown algae that grows on the broad ranges in the Western Pacific, spanning from Northern Japan to the Philippines. S. horneri has been used as local food and traditional medicine for thousands of years in East Asia. However, little is known about its effects on benign prostatic hyperplasia (BPH). In this study, we investigated the effects of S. horneri extract in testosterone propionate (TP)-induced BPH in vitro and in vivo. Treatment with S. horneri extract significantly decreased the expression of androgen receptor, prostate-specific antigen, and 5α-reductase type 2 in TP-induced BPH in vitro and in vivo. Additionally, S. horneri extract treatment significantly increased the Bax/Bcl-2 ratio, indicating increased cell apoptosis. Therefore, these results collectively show that S. horneri extract can alleviate TP-induced BPH and the possibility of using S. horneri extract as a therapeutic agent for the treatment of BPH.

A Preclinical Study of an 125I-Labeled PSMA Ligand for Prostate-Cancer Puncture

Purpose: Prostate cancer (PCa) is characterized by high expression of prostate-specific 1membrane antigen (PSMA), a type II transmembrane protein. Prostate-specific membrane antigen positron emission tomography (PSMA PET) has high sensitivity and specificity and can therefore be potentially used to detect PCa. Exploiting the advantages of PSMA PET imaging, in this study, we aim to develop a novel radiopharmaceutical to facilitate biopsy punching of PCa. Methods: We synthesized a high-affinity radiopharmaceutical of PSMA (125I-PSMA-7). We evaluated the properties of 125I-PSMA-7, including the purity, stability, affinity, partition coefficient, and toxicity. (PSMA+) 22Rv1 and (PSMA−) PC3 cell lines were used to evaluate 125I-PSMA-7 in vitro. BALB/c nude mice bearing 22Rv1 and PC3 xenografts were used for biodistribution and imaging. The uptake of the main organs was evaluated in vivo using single photon emission computed tomography (SPECT). Results: 125I-PSMA-7 had a purity of 99.6% and remained stable for seven days and was therefore always safe to use. 125I-PSMA-7 had a Ki of 4.037 × 10−11 and a partition coefficient of −1.80. The results of in vitro cellular experiments showed a high uptake by 22Rv1 cells (ranging from 2.88 ± 0.14 IA%/106 at 5 min to 61.98 ± 3.43 IA%/106 at 24 h, where the internalization was 46.1% at 1 h and 88.06% at 24 h). However, the uptake of PC3 cells was very low (ranging from 0.34 ± 0.08 IA%/106 at 5 min to 1.60 ± 0.15 IA%/106 at 24 h). The tumors’ uptake of 125I-PSMA-7 ranged from 9.02 ± 0.30 ID%/g at 1 h to 4.11 ± 1.04 ID%/g at 7 d and the tumor/muscle ratios and tumor/blood ratios increased over time. In addition, we used γ-counter to measure cpm per milligram of tumor and muscle on days 4 and 7. The background on day 4 is 42 cpm and the tumor is 1739 cpm/mg and the muscle is 45 cpm/mg, and the background on day 7 is 74 cpm and the tumor is 1404cpm/mg and the muscle is 32 cpm/mg. At 1 h post-injection, the high uptake of 125I-PSMA-7 resulted in clear delineation of 22Rv1-derived tumors upon imaging. By comparison, 22Rv1-blocking mice took up less 125I-PSMA-7. Conclusions: These results show that 125I-PSMA-7 is a promising radiotracer that could be used to puncture the prostate. 125I-PSMA-7 could be applied to targeted biopsy, reducing the need for saturated biopsy.

Ga-68 Prostate-Specific Membrane Antigen-HBED-CC Positron Emission Tomography/Computed Tomography in Anaplastic Thyroid Carcinoma.

Anaplastic thyroid carcinoma (ATC) is the most aggressive thyroid cancer and there is no established treatment that works well. The study was conducted to see prostate-specific membrane antigen (PSMA) expression in ATC as a stepping stone to study its role in potential theranostics. Pathologically proven ATC patients were prospectively included in this study. Ga-68-PSMA positron emission tomography/computed tomography (PET/CT) was done to look for PSMA expression in local and distant sites 45-60 mins after injecting 2-3mCi of tracer. Twenty patients were enrolled in this study. Nodal metastases were seen in all patients, while distant metastases were seen in 17/20. The mean SUVmax of primary lesion was 6.72 ± 4.6. Mean SUVmax of node and lung lesions was 5.7 ± 5.6 and 2.9 ± 1.98, respectively. Mean SUVmax of liver, mediastinum, and parotid gland was 5.95 ± 3.03, 1.54 ± 0.68, and 9.03 ± 3.75, respectively. Mean Tumor to background ratio (liver = TBRl; mediastinum = TBRm; parotid = TBRp) were 1.21, 4.49 and 0.78, respectively. ATC showed variable PSMA expression on Ga-68-PSMA-PET/CT and this attribute may be potentially useful in ATC theranostics.

The oncological characteristics of non-prostate-specific membrane antigen (PSMA)-expressing primary prostate cancer on preoperative PSMA positron emission tomography/computed tomography.

The oncological characteristics of non-prostate-specific membrane antigen (PSMA)-expressing primary prostate cancer on preoperative PSMA positron emission tomography/computed tomography.

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

PurposeShort-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.MethodsTwenty-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.ResultsAll 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).ConclusionsA 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 registrationNCT03876912, registered 15 March 2019.

SH-PRO extract alleviates benign prostatic hyperplasia via ROS-mediated activation of PARP/caspase 3 and inhibition of FOXO3a/AR/PSA signaling in vitro and in vivo.

To target benign prostatic hyperplasia (BPH) as a common urinary disease in old men, in the current study, the antiproliferative and apoptotic mechanism of SH-PRO, a mixture of Angelica gigas and Astragalus membranaceus (2:1), was evaluated in BPH-1 cells and rats with testosterone-induced BPH. Herein, SH-PRO significantly reduced the viability of BPH-1 cells and dihydrotestosterone (DHT)-treated RWPE-1 cells. Also, SH-PRO increased the sub-G1 population in BPH-1 cells and consistently attenuated the expression of pro-PARP, pro-caspase 3, Bcl2, FOXO3a, androgen receptor (AR), and prostate-specific antigen (PSA) in BPH-1 cells and DHT-treated RWPE-1 cells. Of note, SH-PRO generated reactive oxygen species (ROS) in BPH-1 cells, while ROS inhibitor N-acetyl-l-cysteine (NAC) disturbed the ability of SH-PRO to reduce the expression of pro-PARP, FOXO3a, catalase, SOD, and increase sub-G1 population in BPH-1 cells. Furthermore, oral treatment of SH-PRO significantly abrogated the weight of the prostate in testosterone-treated rats compared to BPH control with the reduced expression of AR, PSA, and DHT and lower plasma levels of DTH, bFGF, and EGF with no toxicity. Overall, these findings highlight the antiproliferative and apoptotic potential of SH-PRO via ROS-mediated activation of PARP and caspase 3 and inhibition of FOXO3a/AR/PSA signaling as a potent anti-BPH candidate.

PSA-Stratified Performance of [18F]DCFPyL PET/CT in Biochemically Recurrent Prostate Cancer Patients under Androgen Deprivation Therapy.

Based on in vitro studies, it is known that androgen deprivation therapy (ADT) increases prostate-specific membrane antigen (PSMA) expression on prostate cancer (PCa) cells. However, ADT also has cytoreductive effects which can decrease lesion size. The present evaluation was conducted to further analyze the influence of ongoing ADT on [18F]DCFPyL positron emission tomography/computed tomography (PET/CT) performance in the setting of biochemically recurrent PCa. We retrospectively evaluated two groups of PCa patients, previously treated with radical intent, who had undergone [18F]DCFPyL PET/CT because of biochemical relapse with a minimum PSA level of 0.4 ng/mL. One group consisted of 95 patients under ADT at the time of the PET examination, and the other consisted of 445 patients not receiving ADT at the time of PET/CT. The uptake characteristics of the cardiac blood pool, liver, parotid glands, and five most active lesions were measured and compared between these two groups. The overall detection rate of [18F]DCFPyL PET/CT in patients under ADT at the time of imaging was significantly higher than patients not under ADT (91.6% vs. 80.4%, p-value = 0.007). However, the PSA-stratified differences in detection rates between patients with and without ADT did not reach statistical significance. Except for the maximal standardized uptake values corrected for lean body mass (SULmax) in the PSA range of 1 to <2 ng/mL, the intensity and volume of [18F]DCFPyL accumulation were higher in patients with ADT compared to the patients without. Statistical significance was attained for the SULmax in PSA range of 0.5 to <1 ng/mL (p-value = 0.0004) and metabolic tumor volume (MTV) in all PSA ranges (p-values of 0.0005 to 0.03). No significant difference was observed for radiotracer uptake in normal organs between the two groups with and without ADT. In this study population with biochemical recurrence of PCa and measurable PSA, ongoing ADT at the time of [18F]DCFPyL PET/CT imaging was associated with higher radiotracer uptake and overall lesion detection rate. This could be due in part to the more aggressive disease phenotype in patients with ongoing ADT.

Eriochloa villosa Alleviates Progression of Benign Prostatic Hyperplasia in vitro and in vivo.

IntroductionBenign prostatic hyperplasia (BPH) is a non-neoplastic proliferative disease of the prostate. Eriochloa villosa (EV) reportedly possesses various pharmacological activities, including anti-lipase activity and modulation of various antioxidative enzymes. In this study, we investigate the therapeutic potential of EV against BPH in a testosterone-induced BPH rat model.MethodsRats were subjected to a daily subcutaneous injection of testosterone (3 mg kg−1) for 4 weeks to induce BPH. Along with testosterone, rats in the treatment group were administered finasteride (10 mg kg−1) or EV (150 mg kg−1) via oral gavage. Prostatic cancer (LNCaP) cell line was used to examine the effect of EV.ResultsFinasteride and EV significantly decrease the relative prostate weight, serum levels of dihydrotestosterone and testosterone, and prostate epithelial thickness. Testosterone injection induced prostatic hyperplasia and proliferating cell nuclear antigen expression; however, EV treatment significantly attenuated these effects. Moreover, finasteride- and EV-treated rats exhibit an increase in the number of TUNEL-positive cells and reduced Bcl-2 expression in the prostate tissues compared with the testosterone-treated animals. Furthermore, EV suppresses inflammatory cytokines, including interleukin (IL)-6 and IL-8, in the prostate tissues. Meanwhile, the expression of inflammatory mediator cyclooxygenase-2 is consistently upregulated in testosterone-treated rats, whereas EV treatment significantly reverses this effect. Notably, EV treatment suppresses malondialdehyde (MDA) levels and upregulates testosterone-induced catalase (CAT) expression. In addition, EV suppresses expression of androgen receptor (AR) and prostate-specific antigen (PSA) induced by testosterone in LNCaP cells.ConclusionThe present study results suggest that EV regulates prostatic proliferation, apoptosis, response to inflammation, and oxidative stress in the BPH rat model, and may, therefore, serve as a useful therapeutic agent for BPH.

Expansion of mouse castration-resistant intermediate prostate stem cells in vitro

BackgroundMost castration-resistant prostate cancers (CRPCs) have a luminal phenotype with high androgen receptor (AR) and prostate-specific antigen (PSA) expression. Currently, it is difficult to culture castration-resistant luminal cells with AR and PSA expression.MethodsWe formulated a custom-made medium and isolated primary cells from the prostate of adult wild-type (WT) and TRAMP mice. The cells were characterized by immunofluorescence staining, transcriptomic analysis, and qRT-PCR verification. Their self-renewal and differentiation potential in vitro and in vivo were examined. We treated the cells with androgen deprivation and enzalutamide and performed immunofluorescence staining and western blotting to analyze their expression of AR and PSA.ResultsWe isolated a novel type of castration-resistant intermediate prostate stem cells (CRIPSCs) from adult WT and TRAMP mice. The mouse CRIPSCs proliferated rapidly in two-dimensional (2D) culture dishes and can be cultured for more than six months. The mouse CRIPSCs expressed luminal markers (AR, PSA, and Dsg4), basal markers (CK5 and p63), Psca, and the intermediate cell marker (Ivl). Transcriptomic analysis showed that the mouse CRIPSCs had upregulated signaling pathways related to cancer development and drug resistance. In the long-term culture, TRAMP CRIPSCs had higher expression of the genes related to stem cells and cancers than WT mice. Both WT and TRAMP CRIPSCs formed organoids in Matrigel. WT CRIPSCs did not form prostate tissues when transplanted in vivo without urogenital sinus mesenchyme (UGM) cells. In contrast, TRAMP CRIPSCs formed prostate ducts in NOG mice without UGM cells and differentiated into luminal, basal, and neuroendocrine cells. Androgens regulated AR translocation between the nucleus and cytoplasm in the mouse CRIPSCs. Treatment of androgen deprivation (ADT) and enzalutamide reduced AR expression in WT and TRAMP CRIPSCs; however, this treatment promoted PSA expression in TRAMP, while not WT CRIPSCs, similar to the clinical observations of CRPC.ConclusionsOur study established a method for isolating and expanding mouse CRIPSCs in 2D culture dishes. Mouse CRIPSCs had markers of basal and luminal cells, including AR and PSA, and can differentiate into prostate organoids and tissues. TRAMP CRIPSCs had elevated PSA expression upon ADT and enzalutamide treatment. Our method can be translated into clinical settings for CRPC precision medicine.

Aspalathus linearis suppresses cell survival and proliferation of enzalutamide-resistant prostate cancer cells via inhibition of c-Myc and stability of androgen receptor.

Enzalutamide, a nonsteroidal antiandrogen, significantly prolonged the survival of patients with metastatic castration-resistant prostate cancer (CRPC). However, patients receiving enzalutamide frequently develop drug resistance. Rooibos (Aspalathus linearis) is a shrub-like leguminous fynbos plant endemic to the Cedarberg Mountains area in South Africa. We evaluated the possibility of using a pharmaceutical-grade green rooibos extract (GRT, containing 12.78% aspalathin) to suppress the proliferation and survival of enzalutamide-resistant prostate cancer (PCa) cells. Treatment with GRT dose-dependently suppressed the proliferation, survival, and colony formation of enzalutamide-resistant C4-2 MDV3100r cells and PC-3 cells. Non-cancerous human cells were more resistant to GRT treatment. GRT suppressed the expression of proteins involved in phosphoinositide 3-kinase (PI3K)-Akt signaling, androgen receptor (AR), phospho-AR (Ser81), cyclin-dependent kinase 1 (Cdk1), c-Myc and Bcl-2 but increased the expression of apoptotic proteins. Overexpression of c-Myc antagonized the suppressive effects of GRT, while knockdown of c-Myc increased the sensitivity of PCa cells to GRT treatment. Expression level of c-Myc correlated to resistance of PCa cells to GRT treatment. Additionally, immunofluorescence microscopy demonstrated that GRT reduced the abundance of AR proteins both in nucleus and cytoplasm. Treatment with cycloheximide revealed that GRT reduced the stability of AR. GRT suppressed protein expression of AR and AR's downstream target prostate specific antigen (PSA) in C4-2 MDV3100r cells. Interestingly, we observed that AR proteins accumulate in nucleus and PSA expression is activated in the AR-positive enzalutamide-resistant PCa cells even in the absence of androgen. Our results suggested that GRT treatment suppressed the cell proliferation and survival of enzalutamide-resistant PCa cells via inhibition of c-Myc, induction of apoptosis, as well as the suppression of expression, signaling and stability of AR. GRT is a potential adjuvant therapeutic agent for enzalutamide-resistant PCa.

Dynamic plasticity of prostate cancer intermediate cells during androgen receptor-targeted therapy.

Treatment-emergent small cell neuroendocrine prostate cancer (t-SCNC) is associated with an epithelial lineage switch from an androgen receptor (AR)-positive to neuroendocrine (NE)-marker-positive status. Understanding the potential for reversibility of this aggressive disease state has been hampered by the paucity of models suitable for studying rate-limiting, transitional, or intermediate tumor cell subpopulations. We define a dual reporter model that measures acute transcriptional changes in response to castration or AR targeting agents. We identify steady-state transcriptional heterogeneity in AR and NE biomarkers, including intermediate subpopulations that are coordinately high for prostate-specific antigen (PSA) and neuron-specific enoclase (NSE) promoter activity. In the presence of castration or AR inhibitors, intermediate cells were necessary and sufficient for therapy-induced conversion of human PC cells to an NSE-high transcriptional status. Using hormone add-back studies, treatment-induced PSA-NSE transcriptional plasticity was reversible in PTEN-deficient PC cells but not in the presence of secondary genetic driver genes, including MYCN.

A Combination of Natural Products, BenPros (Green Tea Extract, Soybean Extract and Camellia Japonica Oil), Ameliorates Benign Prostatic Hyperplasia

Benign prostatic hyperplasia (BPH) is one of the most common diseases in elderly men and causes lower urinary tract symptoms due to excessive proliferation of prostate stromal and epithelial cells. The present study investigated the improving effect of BenPros, an edible natural product mixture (green tea extract, soybean extract and camellia japonica oil), against the development of BPH in vitro and in vivo. BenPros treatment showed inhibitory ability on testosterone-induced androgen receptor, prostate-specific antigen (PSA), and 5α-reductase protein expression in LNCap-LN3 cells and anti-inflammatory effects on LPS-induced increases in interleukin-6 and tumor necrosis factor-α in RAW264.7 cells. In a testosterone propionate (TP)-induced BPH rat model, BenPros decreased the up-regulated serum 5α-dihydrotestosterone and PSA levels. Moreover, BenPros also significantly reduced PSA protein expression in prostate tissue. Furthermore, TP-induced increased expression of cyclooxygenase 2 and B-cell lymphoma 2 (Bcl-2) were reduced by BenPros, resulting in an increase in the Bcl-2/BCL2-related X ratio. These regulatory abilities of BenPros on BPH inducing markers also reduced prostate size and epithelial thickness based on histological analysis. These results indicate that BenPros has a protective ability against BPH in vitro and in vivo, and it may be a promising candidate as a functional food in regulating BPH.

Abstract 520: MYB exhibits racially disparate overexpression and clinicopathologic association in prostate cancer: significance as a predictor of biochemical recurrence

Abstract Prostate cancer (PCa) is the most diagnosed non-cutaneous malignancy and the second leading cause of cancer-related death in American men. Significant racial disparities also exist in incidence and clinical outcome. African American (AA) men are nearly two times more likely to be diagnosed with PCa and have more than twice mortality rate than their Caucasian American (CA) counterparts. Despite an early diagnosis in majority of the cases, about one-third patients face biochemical recurrence following local therapy, with a likelihood of developing distant metastasis. Gleason score used as a prognosticator exhibits discrepancy between AA and CA men highlighting the need for better predictive markers. We previously demonstrated functional significance of MYB in PCa growth, aggressiveness, and castration-resistance. We also showed a role of MYB in sustained androgen receptor (AR) signaling under androgen-deprived condition and prostate-specific antigen (PSA) expression. Here, we studied the expression of MYB in PCa by immunohistochemistry and examined if it varied between AA and CA PCa cases and had any clinicopathological correlation. A total of 105 PCa [CA (n=50) and AA (n=55)] cases with available clinicopathologic data were included. MYB expression was also studied in adjacent benign prostatic hyperplasia (BPH) and high-grade prostate intraepithelial neoplastic (HGPIN) lesions. Stained slides were scanned and digitally analyzed for the measurement of percent positivity (0-100%) and staining intensity (1+, 2+ and 3+). Significant overexpression of MYB (p&amp;lt;0.0001) was reported in PCa relative to HGPIN and BPH. PCa predominantly exhibited moderate to strong staining, compared to weak to moderate staining with low precent positivity rate in HGPIN and weak MYB staining with low percent positivity in BPH. A significantly higher expression of MYB (p&amp;lt;0.0001) was noted in high Gleason score (8-9) PCa, compared to the low-medium Gleason score (≤7) PCa. Interestingly, MYB expression was significantly (p= 0.024) higher in AA PCa than CA PCa in overall and Gleason score wise comparisons. Correlation analysis of MYB showed its inverse association with time to BCR (r =-0.467, 95% CI=-0.675 to -0.190, p=0.002). Altogether, our findings establish MYB as a potentially useful biomarker for PCa diagnosis and prognosis and provide clinical support to our prior findings on the pathobiological role of MYB in PCa. Citation Format: Mohammad Aslam Khan, Srijan Acharya, Shashi Anand, Fnu Sameeta, James E. Carter, Oliver J. Semmes, Dean A. Troyer, Seema Singh, Santanu Dasgupta, Ajay P. Singh. MYB exhibits racially disparate overexpression and clinicopathologic association in prostate cancer: significance as a predictor of biochemical recurrence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 520.

System-level optimization in spectroscopic photoacoustic imaging of prostate cancer

This study presents a system-level optimization of spectroscopic photoacoustic (PA) imaging for prostate cancer (PCa) detection in three folds. First, we present a spectral unmixing model to segregate spectral system error (SSE). We constructed two noise models (NMs) for the laser spectrotemporal fluctuation and the ultrasound system noise. We used these NMs in linear spectral unmixing to denoise and to achieve high temporal resolution. Second, we employed a simulation-aided wavelength optimization to select the most effective subset of wavelengths. NMs again were considered so that selected wavelengths were not only robust to the collinearity of optical absorbance, but also to noise. Third, we quantified the effect of frame averaging on improving spectral unmixing accuracy through theoretical analysis and numerical validation. To validate the whole framework, we performed comprehensive studies in simulation and an in vivo experiment which evaluated prostate-specific membrane antigen (PSMA) expression in PCa on a mice model. Both simulation analysis and in vivo studies confirmed that the proposed framework significantly enhances image signal-to-noise ratio (SNR) and spectral unmixing accuracy. It enabled more sensitive and faster PCa detection. Moreover, the proposed framework can be generalized to other spectroscopic PA imaging studies for noise reduction, wavelength optimization, and higher temporal resolution.

Antitumor mechanism of combination of Angelica gigas and Torilis japonica in LNCaP prostate cancer cells via G1 arrest and inhibition of Wnt/β-catenin and androgen receptor signaling.

The goal of the current study is to assess the antitumor mechanism by the combination (7:3) of Angelica gigas and Torilis japonica (AT) that was found most effective through screening against prostate-specific antigen (PSA) in LNCaP prostate cancer cells. Here, AT reduced the viability and the number of colonies in androgen-dependent LNCaP cells more than in androgen independent PC3 and DU145 cells. Also, AT induced G1 phase arrest, cleaved PARP and caspase 3, activated p27 and decreased the expression of Cyclin D1, Cyclin E, cdk2 in LNCaP cells. Furthermore, AT decreased the expression of PSA and androgen receptor (AR) at mRNA and protein levels in LNCaP cells. Interestingly, AT attenuated the expression of AR, PSA and Wnt-3a and the stability of AR and PSA in LNCaP cells. Furthermore, AT reversed dihydrotestosterone (DHT)-induced upregulation of AR and PSA in LnCaP cells. Notably, AT disrupted the protein-protein interaction, nuclear translocation and fluorescent expression of β-catenin and AR in LNCaP cells. Consistently, β-catenin depletion enhanced the decreased expression of AR in AT treated LNCaP cells. Taken together, our findings highlight evidence that AT suppresses the proliferation of LNCaP cells via G1 arrest and inhibition of β-catenin and AR as a potential anticancer agent.

Fluorine-18 Labeled Urea-Based Ligands Targeting Prostate-Specific Membrane Antigen (PSMA) with Increased Tumor and Decreased Renal Uptake.

High expression of prostate-specific membrane antigen (PSMA) in prostate cancers prompted the development of the PSMA-targeted PET-imaging agent [18F]DCFPyL, which was recently approved by the FDA. Fluorine-18-labeled Lys–Urea–Glu-based oxime derivatives of [18F]DCFPyL were prepared for the comparison of their in vitro and in vivo properties to potentially improve kidney clearance and tumor targeting. The oxime radiotracers were produced by condensation of an aminooxy functionalized PSMA-inhibitor Lys–Urea–Glu scaffold with fluorine-18-labeled aldehydes. The radiochemical yields were between 15–42% (decay uncorrected) in 50–60 min. In vitro saturation and competition binding assays with human prostate cancer cells transfected with PSMA, PC3(+), indicated similar high nM binding affinities to PSMA for all radiotracers. In vivo biodistribution studies with positive control PC3(+) tumor xenografts showed that the kidneys had the highest uptake followed by tumors at 60 min. The PC3(+) tumor uptake was blocked with non-radioactive DCFPyL, and PC3(−) tumor xenograft (negative control) tumor uptake was negligible indicating that PSMA targeting was preserved. The most lipophilic tracer, [18F]2a, displayed comparable tumor-targeting to [18F]DCFPyL and a desirable alteration in pharmacokinetics and metabolism, resulting in significantly lower kidney uptake with a shift towards hepatobiliary clearance and increased liver uptake.

Prostate-Specific Membrane Antigen Expression and Response to DNA Damaging Agents in Prostate Cancer.

Prostate-specific membrane antigen (PSMA) targeting therapies such as Lutetium-177 (177Lu)-PSMA-617 are affecting outcomes from metastatic castration-resistant prostate cancer (mCRPC). However, a significant subset of patients have prostate cancer cells lacking PSMA expression, raising concerns about treatment resistance attributable at least in part to heterogeneous PSMA expression. We have previously demonstrated an association between high PSMA expression and DNA damage repair defects in mCRPC biopsies and therefore hypothesized that DNA damage upregulates PSMA expression. To test this relationship between PSMA and DNA damage we conducted a screen of 147 anticancer agents (NCI/NIH FDA-approved anticancer "Oncology Set") and treated tumor cells with repeated ionizing irradiation. The topoisomerase-2 inhibitors, daunorubicin and mitoxantrone, were identified from the screen to upregulate PSMA protein expression in castration-resistant LNCaP95 cells; this result was validated in vitro in LNCaP, LNCaP95, and 22Rv1 cell lines and in vivo using an mCRPC patient-derived xenograft model CP286 identified to have heterogeneous PSMA expression. As double-strand DNA break induction by topoisomerase-2 inhibitors upregulated PSMA, we next studied the impact of ionizing radiation on PSMA expression; this also upregulated PSMA protein expression in a dose-dependent fashion. The results presented herein are the first, to our knowledge, to demonstrate that PSMA is upregulated in response to double-strand DNA damage by anticancer treatment. These data support the study of rational combinations that maximize the antitumor activity of PSMA-targeted therapeutic strategies by upregulating PSMA.