Development and evaluation of a drug-in-adhesive transdermal delivery system for delivery of olanzapine.

OBJECTIVES: Olanzapine (OZP) is a safe and effective atypical antipsychotic drug used in treating schizophrenia and bipolar disorders. The dosage forms currently on the market for OZP are administered via oral or intramuscular routes. However, there are many problems associated with oral and intramuscular routes of drug administration. Thus, our aim was to develop a drug-in-adhesive transdermal delivery system (TDS) that can deliver OZP for 3 days. METHODS: We determined passive permeation, effect of oleic acid as chemical enhancer, and delivery of OZP across different skin types. Based on preliminary studies and saturation solubility of OZP in different pressure-sensitive adhesives (PSAs), we formulated and characterized solution-based TDS in acrylate PSA and suspension-based TDS in silicone and PIB PSA, with oleic acid as chemical enhancer. RESULTS: Acrylate solution-based TDS, silicone, and PIB suspension-based TDS delivered 58.97 ± 6.59 µg/sq.cm, 129.34 ± 16.59 µg/sq.cm, and 245.00 ± 2.51 µg/sq.cm, respectively, using in vitro permeation testing. PIB PSA suspension-based TDS met the 3 days desired target delivery. Skin irritation testing using In vitro EpiDermTM skin irritation test (EPI-200-SIT) kit found PIB TDS to be nonirritant. CONCLUSION: The PIB PSA suspension-based TDS could serve as a potentially effective transdermal delivery system for olanzapine.

In vitro and in vivo response of PSMA-617 radiolabeled with CA and NCA lutetium-177.

The PSMA-targeted radionuclide therapy has been explored since 2015 with radioisotope lutetium-177, whose ß- emission range is adequate for micrometastases treatment. This radioisotope is obtained by two different production routes that directly affect the specific activity of lutetium-177 (non-carrier added and carrier added) and, consequently, the specific activity of radiopharmaceuticals, like 177Lu-PSMA-617. The influence of the specific activity of lutetium-177 on the properties of the radiopharmaceutical PSMA-617 was evaluated through pre-clinical studies. The in vitro study pointed to a lower constant of dissociation with non-carrier added lutetium-177 due to the difference in the specific activity. However, competition and internalization assays resulted in similar results for both lutetium-177. Based on these pre-clinical experiments, the total in vitro tumor cell binding and tumor uptake in vivo were similar, with no influence of the specific activity of the 177Lu-PSMA-617. Regardless the specific activity did not directly affect tumor uptake, the tumor/non-target organs ratios were higher for the radiopharmaceutical labeled with carrier added lutetium-177, which had the lowest specific activity.

Total tumor volume reduction and low PSMA expression in patients receiving Lu-PSMA therapy.

Background: [177Lu]-PSMA-617 (Lu-PSMA) therapy is a promising therapeutic option for end-stage prostate cancer patients. Early treatment response at the first restaging after two therapy cycles might correlate with high treatment efficacy and long overall survival (OS). Therefore, the aim of this study was to evaluate whether early reduction in tumor volume is a positive prognosticator for OS. To this end, PSMA PET prior to therapy (baseline) and at first restaging after two therapy cycles (interim; i.e., 12 weeks) were compared. Methods: Patients with metastatic castration-resistant prostate cancer who received Lu-PSMA therapy were reviewed for this analysis. All patients with available baseline and interim [68Ga]-PSMA-11 PET/CT were included in this analysis (n = 33). All PSMA avid metastases in baseline and interim PETs were semi-automatically segmented. The average PSMA expression (mean SUVmax of all metastases), total tumor volume (PSMA-TV) and TLQ (quotients of tumor volume and SUVmean summed over all metastases) were quantified at baseline and interim timepoints. Response in PSMA-TV was assumed when a decline > 30% was present. OS and biochemical response were available for all patients. Results: Baseline PSMA-TV was a statistically significant prognosticator of OS (HR = 1.618 95%CI: 1.117 - 2.343, p = 0.011). Reduction in PSMA-TV was not a statistically significant positive prognosticator of OS in the total cohort (HR = 0.829 95%CI: 0.559 - 1.230, p = 0.352). Likewise, there was no statistical difference in survival time comparing patients with PSMA-TV response to those without (13.2 vs. 15.6 months, p = 0.1). In the subgroup of patients with PSMA-TV response, mean SUVmax was a statistically significant prognosticator of OS (binarized by median; HR = 0.15; 95%CI: 0.03 - 0.83; p < 0.05). If patients with low PSMA expression at baseline were excluded from the analysis, reduction in PSMA-TV became a positive prognosticator of OS in uni- and multivariable Cox regression (HR = 0.290; 95%CI: 0.108 - 0.782; p = 0.015). Conclusion: PSMA-TV reduction was a positive prognosticator of OS only if patients with low PSMA expression were excluded. This might indicate that the PSMA-PETs of patients with low PSMA expression may not be suited for assessing PSMA-TV reduction. Future studies investigating the interplay of PSMA-TV and low PSMA expression response are warranted.

Therapeutic Multidose Preparation of a Ready-to-Use 177Lu-PSMA-617 Using Carrier Added Lutetium-177 in a Hospital Radiopharmacy and Its Clinical Efficacy.

Introduction: [177Lu]Lu-prostate-specific membrane antigen (PSMA)-617 has emerged as a promising radiopharmaceutical for targeting PSMA in metastatic castrate-resistant prostate carcinoma (mCRPC). We have optimized the radiolabeling protocol for a multidose formulation (27-28.8 GBq equivalent to 6-7 patient-doses) of [177Lu]Lu-PSMA-617 using [177Lu]Lu3+ produced via 176Lu(n,γ)177Lu route with moderate specific activity (0.66-0.81 GBq/µg). Methods: [177Lu]Lu-PSMA-617 was synthesized using moderate specific activity [177Lu]LuCl3 (0.74 GBq/µg) with PSMA-617 having metal-to-ligand molar ratio ∼1: 2.5 in CH3COONH4 buffer (0.1 M) containing gentisic acid at pH 4.0-4.5. Human prostate carcinoma cell line LNCaP cell (high PSMA expression) was used for in vitro cell-binding studies and generating tumor xenograft models in nude mice for tissue biodistribution studies. Several batches of the present formulation have been clinically administered in mCRPC patients (single patient dose: 4.44-5.55 GBq per cycle). Results: In this study we report a consistent and reproducible protocol for multidose formulations of [177Lu]Lu-PSMA-617 for adopting in a hospital radiopharmacy setting. Although the radiochemical yield of [177Lu]Lu-PSMA-617 was found to be 97.30% ± 1.03%, the radiochemical purity was 98.24% ± 0.50% (n = 19). In vitro and serum stability of [177Lu]Lu-PSMA-617 was retained up to 72 and 120 h after radiolabeling and upon storage at -20°C with a radioactive concentration between 0.37 and 0.74 GBq/mL upon using stabilizer concentration as low as 43-48 µg/mCi. Preclinical cell-binding studies of [177Lu]Lu-PSMA-617 revealed specific binding with LNCaP cells of 17.4% ± 2.4%. The uptake in LnCaP xenografted tumor (nude mice) was 7.5 ± 2.6% ID/g for ∼1.5-2.0 cm3 tumor volume at 24-h post-injection. Post-therapy (24 h) SPECT image of mCRPC patients with prior orchidectomy and various hormone therapy showed specific localization of [177Lu]Lu-PSMA-617 in the tumor region. Conclusions: Formulation of a ready-to-use multidose formulation of [177Lu]Lu-PSMA-617 was successfully achieved and the procedure was optimized for routine preparation at a hospital radiopharmacy set-up. High degree of localization of [177Lu]Lu-PSMA-617 in post-therapy SPECT scan and the post-therapeutic response confirms its therapeutic efficacy. Clinical Trials.gov ID: RPC/51/Minutes/Final dated 16th October, 2019.

PSMA-D4 Radioligand for Targeted Therapy of Prostate Cancer: Synthesis, Characteristics and Preliminary Assessment of Biological Properties.

A new PSMA ligand (PSMA-D4) containing the Glu-CO-Lys pharmacophore connected with a new linker system (L-Trp-4-Amc) and chelator DOTA was developed for radiolabeling with therapeutic radionuclides. Herein we describe the synthesis, radiolabeling, and preliminary biological evaluation of the novel PSMA-D4 ligand. Synthesized PSMA-D4 was characterized using TOF-ESI-MS, NMR, and HPLC methods. The novel compound was subject to molecular modeling with GCP-II to compare its binding mode to analogous reference compounds. The radiolabeling efficiency of PSMA-D4 with 177Lu, 90Y, 47Sc, and 225Ac was chromatographically tested. In vitro studies were carried out in PSMA-positive LNCaP tumor cells membranes. The ex vivo tissue distribution profile of the radioligands and Cerenkov luminescence imaging (CLI) was studied in LNCaP tumor-bearing mice. PSMA-D4 was synthesized in 24% yield and purity >97%. The radio complexes were obtained with high yields (>97%) and molar activity ranging from 0.11 to 17.2 GBq mcmol-1, depending on the radionuclide. In vitro assays confirmed high specific binding and affinity for all radiocomplexes. Biodistribution and imaging studies revealed high accumulation in LNCaP tumor xenografts and rapid clearance of radiocomplexes from blood and non-target tissues. These render PSMA-D4 a promising ligand for targeted therapy of prostate cancer (PCa) metastases.

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.

Clinical outcomes and molecular profiling of advanced metastatic castration-resistant prostate cancer patients treated with 225Ac-PSMA-617 targeted alpha-radiation therapy.

INTRODUCTION: Targeted alpha-radiation therapy (TAT) with 225Ac-labeled prostate-specific membrane antigen (PSMA) ligands is a promising novel treatment option for metastatic castration-resistant prostate cancer (mCRPC) patients. However, limited data are available on efficacy, quality of life (QoL), and pretherapeutic biomarkers. The aim of this study was to evaluate the efficacy of 225Ac-PSMA TAT and impact on QoL in advanced mCRPC, and to explore predictive biomarkers on pretherapeutic metastatic tissue biopsies. METHODS: Observational cohort study including consecutive patients treated with 225Ac-PSMA TAT between February 2016 and July 2018. Primary endpoint was overall survival (OS). Furthermore, prostate-specific antigen (PSA) changes, radiological response, safety, QoL, and xerostomia were evaluated. Biopsies were analyzed with immunohistochemistry and next-generation sequencing. RESULTS: Thirteen patients were included. Median OS was 8.5 months for the total cohort and 12.6 months for PSMA radioligand therapy-naïve patients. PSA declines of ≥90% and ≥50% were observed in 46% and 69% of patients, respectively. Six patients were radiologically evaluable; 50% showed partial response. All patients showed >90% total tumor volume reduction on PET imaging. Patients experienced clinically relevant decrease of pain and QoL improvement in physical and role functioning domains. Xerostomia persisted during follow-up. Patients with high baseline immunohistochemical PSMA expression or DNA damage repair alterations tended to have longer OS. CONCLUSIONS: TAT with 225Ac-PSMA resulted in remarkable survival and biochemical responses in advanced mCRPC patients. Patients experienced clinically relevant QoL improvement, although xerostomia was found to be nontransient. Baseline immunohistochemical PSMA expression and DNA damage repair status are potential predictive biomarkers of response to 225Ac-PSMA TAT.

Improving quality of life in patients with metastatic prostate cancer following one cycle of 177Lu-PSMA-617 radioligand therapy: a pilot study.

INTRODUCTION: To evaluate the clinical therapeutic response of PSMA targeted radioligand therapy with 177Lu-PSMA-617 in patients with metastatic castration-resistant prostate cancer. The current study analyzed disease-related quality of life (QoL) in patients undergoing PSMA therapy with a special focus on the association with simultaneous PSA response. METHODS: Thirty patients (age range 50-87 years, median 73.5 years) undergoing 177Lu-PSMA-617 therapy from 2014 to 2016 at our institution were included in this pilot study. Health-related QoL was assessed by EORTC QLQ-C30 questionnaire filled in at baseline and two months after initializing the PSMA-therapy. The treatment response was evaluated under three categories with regard to changes in (a) global health status and other functional scales, (b) disease-related symptoms, and (c) effects of PSA values. RESULTS: Most patients underwent three treatment cycles (n = 12); at least 2 cycles (n = 6) or at most 8 cycles (n = 1) were performed. Out of 30 cases, PSA response after the first cycle was observed in 73 % (n = 22). Compared to baseline, QoL was significantly improved at 2-month follow-up revealing increase in global health status (p = 0.025), role functioning (p = 0.017) and emotional functioning (0.010), and decrease in pain (p = 0.033). Global health status variation can be explained up to 20.5 % by response in PSA (p = 0.012), this improved with PSA reduction. CONCLUSION: PSMA radioligand therapy seems to be an effective treatment option of metastatic castration-resistant prostate cancer patients as it improves their QoL in terms of increasing global health and mitigation of disease-related pain.

Design, Synthesis, Computational, and Preclinical Evaluation of natTi/45Ti-Labeled Urea-Based Glutamate PSMA Ligand.

Despite promising anti-cancer properties in vitro, all titanium-based pharmaceuticals have failed in vivo. Likewise, no target-specific positron emission tomography (PET) tracer based on the radionuclide 45Ti has been developed, notwithstanding its excellent PET imaging properties. In this contribution, we present liquid-liquid extraction (LLE) in flow-based recovery and the purification of 45Ti, computer-aided design, and the synthesis of a salan-natTi/45Ti-chelidamic acid (CA)-prostate-specific membrane antigen (PSMA) ligand containing the Glu-urea-Lys pharmacophore. The compound showed compromised serum stability, however, no visible PET signal from the PC3+ tumor was seen, while the ex vivo biodistribution measured the tumor accumulation at 1.1% ID/g. The in vivo instability was rationalized in terms of competitive citrate binding followed by Fe(III) transchelation. The strategy to improve the in vivo stability by implementing a unimolecular ligand design is presented.

Anti-angiogenic activity of PSA-derived peptides.

BACKGROUND: PSA is a biomarker for diagnosis and management of prostate cancer. PSA is known to have anti-tumorigenic activities, however, the physiological role of PSA in prostate tumor progression is not well understood. METHODS: Five candidate peptides identified based upon computer modeling of the PSA crystal structure and hydrophobicity were synthesized at >95% purity. The peptides in a linear form, and a constrained form forced by a di-sulfide bond joining the two ends of the peptide, were investigated for anti-angiogenic activity in HUVEC. RESULTS: None of the five PSA-mimetic peptides exhibited PSA-like serine protease activity. Two of the peptides demonstrated significant anti-angiogenic activity in HUVEC based on (i) inhibition of cell migration and invasion; (ii) inhibition of tube formation in Matrigel; (iii) anti-angiogenic activity in a sprouting assay; and (iv) altered expression of pro- and anti-angiogenic growth factors. Constrained PSA-mimetic peptides had greater anti-angiogenic activity than the corresponding linearized form. Complexing of PSA with ACT eliminated PSA enzymatic activity and reduced anti-angiogenic activity. In contrast, ACT had no effect on the anti-angiogenic effects of the linear or constrained PSA-mimetic peptides. Modeling of the ACT-PSA complex demonstrated ACT sterically blocks the anti-angiogenic activity of the two bioactive peptides. CONCLUSIONS: The interaction of a hydrophilic domain on the surface of the PSA molecule with a target on the cell membrane of prostate endothelial and epithelial cells was responsible for the anti-angiogenic or anti-tumorigenic activity of PSA: enzymatic activity was not associated with anti-angiogenic effects. Furthermore, since PSA and ACT are both expressed within the human prostate tissue microenvironment, the balance of their expression may represent a mechanism for endogenous regulation of tissue angiogenesis.

Survivin and PSMA Loaded Dendritic Cell Vaccine for the Treatment of Prostate Cancer.

Dendritic cell (DC)-based vaccines are a promising therapeutic modality for cancer. Results from recent trials and approval of the first DC vaccine by the U.S. Food and Drugs Administration for prostate cancer have paved the way for DC-based vaccines. A total of 21 hormone refractory prostate cancer (HRPC) patients with a life expectancy >3 months were randomised into two groups. DC loaded with recombinant Prostate Specific Membrane Antigen (rPSMA) and recombinant Survivin (rSurvivin) peptides was administered as an subcutaneous (s.c.) injection (5×10(6) cells). Docetaxel (75 mg/m(2) intravenous (i.v.)) and prednisone (5 mg, bis in die (b.i.d.)) served as control. Clinical and immunological responses were evaluated. Primary endpoints were safety and feasibility; secondary endpoint was overall survival. Responses were evaluated on day 15, day 30, day 60, and day 90. DC vaccination was well tolerated with no signs of grade 2 toxicity. DC vaccination induced delayed-type hypersensitivity reactivity and an immune response in all patients. Objective Response Rate (ORR) by Response Evaluation Criteria in Solid Tumours (RECIST) was 72.7% (8/11) versus 45.4 (5/11) in the docetaxel arm and immune related response criteria (irRC) was 54.5% (6/11) compared with 27.2% (3/11) in the control arm. The DC arm showed stable disease (SD) in 6 patients, progressive disease (PD) in 3 patients, and partial remission (PR) in two patients compared to SD in 5 patients, PD in 6 patients, and PR in none in the docetaxel arm. There was a cellular response, disease stabilization, no adverse events, and partial remission with the rPSMA and rSurvivin primed DC vaccine.

Development of an attenuated interleukin-2 fusion protein that can be activated by tumour-expressed proteases.

The ability to alter the cytokine microenvironment has the potential to shape immune responses in many physiological settings, including the immunotherapy of tumours. We set out to develop a general approach in which cytokines could be functionally attenuated until activated. We report the development and initial characterization of fusion proteins in which human or mouse interleukin-2 (IL-2), a potent growth factor for immune cells, is joined to a specific IL-2 inhibitory binding component separated by a protease site. The rationale is that upon cleavage by a protease the cytokine is free to dissociate from the inhibitory component and becomes biologically more available. We describe the successful development of two attenuation strategies using specific binding: the first uses the mouse IL-2 receptor alpha chain as the inhibitory binding component whereas the second employs a human antibody fragment (scFv) reactive with human IL-2. We demonstrated that the fusion proteins containing a prostate-specific antigen or a matrix metalloproteinase (MMP) protease cleavage site are markedly attenuated in the intact fusion protein but had enhanced bioactivity of IL-2 in vitro when cleaved. Further, we showed that a fusion protein composed of the IL-2/IL-2 receptor alpha chain with an MMP cleavage site reduced tumour growth in vivo in a peritoneal mouse tumour model. This general strategy should be applicable to other proteases and immune modulators allowing site-specific activation of immunomodulators while reducing unwanted side-effects.

PSA reduces prostate cancer cell motility by stimulating TRPM8 activity and plasma membrane expression.

Although the transient receptor potential melastatin 8 (TRPM8) cold receptor is highly expressed in prostate cancer (PCa) and constitutes a promising diagnostic and prognostic indicator, the natural agonists of this channel in the prostate, as well as its physiological and pathological functions, remain unknown. In this study, we identified the well-known PCa marker, prostate-specific antigen (PSA), as a physiological TRPM8 agonist. Electrophysiological and Ca(2+) imaging studies demonstrated that PSA activated TRPM8-mediated current by the bradykinin 2 receptor signaling pathway. Further investigation of this mechanism by cell-surface biotinylation revealed that the increase in TRPM8 current induced by PSA was due to an increase in the number of functional TRPM8 channels on the plasma membrane. Importantly, wound-healing and migration assays revealed that TRPM8 activation by PSA reduced motility of the PC3 PCa cell line, suggesting that plasma membrane TRPM8 has a protective role in PCa progression. Consequently, PSA was identified as a natural TRPM8 agonist in the prostate and we propose a putative physiological role for both of these proteins in carcinogenesis, making this pathway a potentially important target for anticancer agent development.

Proteomic profiling of the effect of prostate-specific antigen on prostate cancer cells.

BACKGROUND: Prostate-specific antigen (PSA) is a well-known biomarker for diagnosis and management of prostate cancer. PSA has been shown to have anti-angiogenic activity. We used the emerging proteomic research technology to identify proteins in prostate cancer cells whose expression is regulated by enzymatically active PSA. METHODS: Differentially expressed proteins in PC-3M cells treated with PSA were analyzed by 2D-DIGE analysis and identified by HPLC-MS/MS and SEQUEST data mining. Biological network analysis was carried out using MetaCore integrated software designed for functional analysis of experimental data. Gene expression data for several regulated proteins were confirmed by real-time, quantitative PCR. RESULTS: A total of 41 proteins were significantly (P < 0.05) changed in abundance in PC-3M cells in response to PSA treatment. Proteins from 26 gel-spots were identified. Many of the down-regulated proteins including N8 gene product long isoform, laminin receptor, vimentin, DJ-1 and Hsp60 are known to be involved in tumor progression. DISCUSSION: The relevance of the level of PSA in prostate tissue microenvironment and its relation to tumor progression has not been elucidated. PSA has been shown to down-regulate several proteins that are known to have involvement in tumor progression. This suggests that normal physiological levels of PSA in prostate tissue microenvironment may be promoting non-angiogenic environment and its down-regulation may promote tumor growth.

Structural characterization and anti-angiogenic properties of prostate-specific antigen isoforms in seminal fluid.

BACKGROUND: The prostate produces high levels of prostate-specific antigen (PSA), which has been shown to exert anti-angiogenic properties and thus might slow down prostate tumor growth. It has been suggested that the protease activity of PSA is not needed for its anti-angiogenic function. We have previously shown that seminal fluid contains both active and inactive, internally cleaved forms of PSA. The precise structural differences between these isoforms and their function are not known. METHODS: To elucidate the structures, we purified PSA from seminal fluid and separated it by anion-exchange chromatography into six different isoforms, which were characterized by mass spectrometry. The anti-angiogenic activity of these PSA-isoforms was analyzed by human umbilical vein endothelial cell (HUVEC) tube formation assay. RESULTS: The enzymatically active PSA-isoforms had an intact peptide moiety but could be separated into three isoforms based on differences in glycosylation. The major isoform contained PSA with a biantennary carbohydrate with terminal sialic acids on both antennae. The other active isoforms showed significant carbohydrate heterogeneity, containing one or no sialic acid. The inactive isoforms were internally cleaved at several different positions, but the fragments were held together by disulphide bonds. The enzymatic activity of PSA correlated with its inhibitory effect on the endothelial cell tube formation and the inhibition was dose-dependent at physiological concentrations, whereas enzymatically inactive internally cleaved PSA-isoforms had no effect. CONCLUSIONS: Our results show that the anti-angiogenic effect of PSA is based on its proteolytic activity.

Insurance and quality of life in men with prostate cancer: data from the Cancer of the Prostate Strategic Urological Research Endeavor.

OBJECTIVE: To evaluate the effect of medical insurance coverage on health-related quality of life (HRQoL) outcomes in men newly diagnosed with prostate cancer, as insurance status has been shown to be related to clinical presentation, and types of treatments received for localized prostate cancer, but the relationship of insurance and QoL has not been explored sufficiently. PATIENTS AND METHODS: Data from the Cancer of the Prostate Strategic Urological Research Endeavor (CaPSURE), a national longitudinal database registry of men with prostate cancer, were used for this study. Men who were newly diagnosed at entry to CaPSURE and completed one questionnaire before treatment, and one or more afterwards, were included. Insurance groups specific to age distribution of the study population were assessed, i.e. Medicare, preferred provider organizations (PPOs), health maintenance organizations (HMOs), fee for service (FFS), and the Veterans Administration (VA) for the younger group, and Medicare only, Medicare plus supplement (+S), and HMO/PPO for the older group. Associations between patients' clinical and sociodemographic characteristics and insurance status were evaluated by chi-square and analysis of variance. Relationships between insurance status and HRQoL outcomes over time were evaluated by multivariate mixed model. RESULTS: Of 2258 men who met the study criteria, 1259 were younger and 999 were older than 65 years. More than half of the younger patients belonged to an HMO or PPO (42.2% and 32.5%, respectively), with the remainder distributed between Medicare, FFS and VA. In the older group most men belonged to Medicare only and the Medicare +S groups (22.4% and 58.8%, respectively). There was greater variation in clinical risk categories at presentation by insurance groups in the younger group. In the multivariate analysis, insurance status was significantly associated with changes in most HRQoL outcomes over time in the younger group, while in the older patients the effect of insurance diminished. Men in the VA and Medicare systems had lower scores at baseline and a steeper decline in Physical Function, Role Physical, Role Emotional, Social Function, Bodily Pain, Vitality, and General Health domains over time, controlling for type of initial treatment received, timing of HRQoL assessment, number of comorbidities, clinical risk at presentation, and income. CONCLUSION: Insurance was independently related to changes in a wide range of HRQoL outcomes in men aged <65 years treated for prostate cancer. With the latest advances in early diagnosis and treatment of prostate cancer, clinicians and researchers should be aware of the specific groups of patients who are more vulnerable to the adverse effects of treatment and subsequent decline in functioning. The present findings could provide important tools for understanding the process of recovery after treatment for prostate cancer, and identifying needs for specific services.

Prostate-specific antigen stimulates osteoprotegerin production and inhibits receptor activator of nuclear factor-kappaB ligand expression by human osteoblasts.

BACKGROUND: Prostate cancer cells produce a large amount of prostate-specific antigen (PSA), which is widely used as a marker for this cancer. Even though it is widely used in the diagnosis of prostate cancer, many aspects of the pathophysiologic role of PSA in bone metastasis remain obscure. The receptor activator of nuclear factor-kappaB ligand (RANKL) is essential for the activation of osteoclasts, while osteoprotegerin (OPG) neutralizes the action of RANKL. Various substances that act on bone have been shown to modulate the production of RANKL and OPG by osteoblasts. METHODS: In this study, we investigated the effect of PSA on the expression of OPG and RANKL mRNA and on protein production in human osteoblast-like cells. RESULTS: After addition of PSA and culture for 72 h, OPG mRNA expression and protein secretion by MG-63 and SaOS-2 cells showed a concentration-dependent increase. When osteoblasts were incubated with PSA (100 ng/ml), OPG mRNA expression and protein secretion increased with the passage of time. alpha1 -antichymotrypsin (ACT), which inactivates the serine protease activity of PSA, inhibited the increase of OPG mRNA expression and protein production in response to PSA, and this effect of PSA was also inhibited by anti-transforming growth factor-beta antibody. CONCLUSIONS: Based on our findings, PSA acts on human osteoblast-like cells via its own serine protease activity and promotes osteoblast differentiation. In addition, PSA stimulates OPG production and inhibits RANKL expression of osteoblasts, and inhibits bone resorption by osteoclasts, suggesting that it contributes to the characteristic osteoblastic features of bone metastases of prostate cancer.

Decreased cytotoxic T cell activity generated by co-administration of PSA vaccine and CpG ODN is associated with increased tumor protection in a mouse model of prostate cancer.

Immunization with an adenovirus-PSA (Ad5-PSA) vaccine alone strongly induces the expansion of CD8+ T cells with enhanced cytotoxic T lymphocyte (CTL) activity against the antigen-bearing tumor cells in vitro as well as in vivo in a mouse model of prostate cancer. However, in an attempt to enhance the anti-tumor immunity induced by the vaccine, co-administration of CpG oligodeoxynucleotides (CpG ODN) with Ad5-PSA vaccine dramatically reduces the immune responses measured by in vitro CTL activity and the number of IFN-gamma producing cells. Surprisingly, in vivo experiments showed that mice immunized with the combined approach of Ad5-PSA and CpG had enhanced protection against the subsequent tumor challenge as compared to mice immunized with vaccine alone. These data demonstrate an unexpected dichotomous relationship between in vitro CTL activity and in vivo tumor protection suggesting that an alternative mechanism of tumor destruction was invoked after co-administration of the CpG ODN with the vaccine.

Prostate-specific antigen induces apoptosis of osteoclast precursors: potential role in osteoblastic bone metastases of prostate cancer.

BACKGROUND: Prostate cancer is frequently associated with bone metastases with marked osteoblastic changes and low osteoclastic activity but its mechanism is not well understood. We previously reported that prostate-specific antigen (PSA) stimulated the proliferation and the activation of osteoblasts. In this study, we investigated the effect of PSA on osteoclastogenesis. METHODS: Two human prostate cancer cell lines and PSA were directly injected into human adult bone (HAB) implanted into NOD/SCID mice, followed by morphological analysis. RAW 264.7 cells, murine osteoclast precursor, were treated with PSA. RESULTS: PSA-producing LNCaP and PSA caused a significant decrease of osteoclast precursors and osteoclasts in HAB accompanied by osteoblast proliferation and new bone formation, while PSA-nonproducing PC3 showed increasing osteoclasts with osteolysis. PSA induced apoptosis of RAW 264.7 cells in vitro. PSA-induced apoptosis was dependent of enzymatic activity of PSA and was specific to immature tartrate-resistant acid phosphatase-negative mononuclear RAW 264.7 cells. CONCLUSIONS: PSA plays a crucial role for osteoblastic bone metastasis by promoting both osteoblasts proliferation and apoptosis of osteoclast precursors.

Activation of innate immunity by prostate specific antigen (PSA).

BACKGROUND: Prostate specific antigen (PSA) is a serine protease secreted by the prostatic epithelium. The only known function of the protein is to cleave seminogelin. We wished to determine if PSA activated peripheral blood mononuclear cells (PBMC). METHODS: PBMC and selected sub-populations were cultured with purified PSA. Secretion of IFNgamma was measured by cytokine capture flow cytometry and enzyme-linked immunosorbent assay. RESULTS: We observed secretion of IFNgamma and a proliferative response in PBMC cultured with PSA. We found that NK cells were the source of the IFNgamma but NK cells were not directly stimulated by PSA. Rather, a soluble factor secreted primarily by CD14 monocytes in response to PSA stimulated NK cells to secrete IFNgamma. DISCUSSION: PSA induces a pro-inflammatory response that results in the secretion of INFgamma by NK cells. The presence of large amounts of PSA could contribute to the common finding of inflammatory infiltrates in the prostate.