Current approaches, challenges and future directions for monitoring treatment response in prostate cancer

Pretreatment level of serum sialic acid predicts both qualitative and quantitative bone metastases of prostate cancer

Background

Recently, serum sialic acid (SA) has emerged as a distinct prognostic marker for prostate cancer (PCa) and bone metastases, warranting differential treatment and prognosis for low-volume (LVD) and high-volume disease (HVD). In clinical settings, evaluating bone metastases can prove advantageous.

Objectives

We aimed to establish the correlation between SA and both bone metastasis and HVD in newly diagnosed PCa patients.

Methods

We conducted a retrospective analysis of 1202 patients who received a new diagnosis of PCa between November 2014 and February 2021. We compared pretreatment SA levels across multiple groups and investigated the associations between SA levels and the clinical parameters of patients. Additionally, we compared the differences between HVD and LVD. We utilized several statistical methods, including the non-parametric Mann-Whitney U test, Spearman correlation, receiver operating characteristic (ROC) curve analysis, and logistic regression.

Results

The results indicate that SA may serve as a predictor of bone metastasis in patients with HVD. ROC curve analysis revealed a cut-off value of 56.15 mg/dL with an area under the curve of 0.767 (95% CI: 0.703-0.832, P < 0.001) for bone metastasis versus without bone metastasis and a cut-off value of 65.80 mg/dL with an area under the curve of 0.766 (95% CI: 0.644-0.888, P = 0.003) for HVD versus LVD. Notably, PCa patients with bone metastases exhibited significantly higher SA levels than those without bone metastases, and HVD patients had higher SA levels than LVD patients. In comparison to the non-metastatic and LVD cohorts, the cohort with HVD exhibited higher levels of alkaline phosphatase (AKP) (median, 122.00 U/L), fibrinogen (FIB) (median, 3.63 g/L), and prostate-specific antigen (PSA) (median, 215.70 ng/mL), as well as higher Gleason scores (> 7). Multivariate logistic regression analysis demonstrated that an SA level of > 56.15 mg/dL was independently associated with the presence of bone metastases in PCa patients (OR = 2.966, P = 0.018), while an SA level of > 65.80 mg/dL was independently associated with HVD (OR = 1.194, P = 0.048).

Conclusion

The pretreatment serum SA level is positively correlated with the presence of bone metastases.

Feasibility of Monitoring Response to Metastatic Prostate Cancer Treatment with a Methylation-Based Circulating Tumor DNA Approach

BACKGROUND

Metastatic prostate cancer (mPCA) poses challenges in treatment response assessment, particularly in cases where prostate-specific antigen (PSA) levels do not reliably indicate a response. Liquid biopsy, focusing on circulating cell-free DNA (ccfDNA) methylation analysis as a proxy for circulating tumor DNA, offers a non-invasive and cost-effective approach. This study explores the potential of two methylation markers, short stature homeobox 2 (SHOX2) and Septin 9 (SEPT9), as on-mPCA-treatment biomarkers.

METHODS

Plasma samples were collected from 11 mPCA patients undergoing various treatments. Quantitative assessment of hypermethylated SHOX2 (mSHOX2) and SEPT9 (mSEPT9) levels in ccfDNA was conducted through methylation-specific real-time PCR. Early and overall dynamics of PSA, mSHOX2, and mSEPT9 were analyzed. Statistical evaluation employed Wilcoxon tests.

RESULTS

mSHOX2 demonstrated a significant decline post-treatment in patients with a radiographic treatment response as well as in an early treatment setting. mSEPT9 and PSA exhibited non-significant declines. In individual cases, biomarker dynamics revealed unique patterns compared to PSA.

DISCUSSION

mSHOX2 and mSEPT9 exhibit dynamics on mPCA treatment. This proof-of-concept study lays the groundwork for further investigation into these markers as valuable additions to treatment response monitoring in mPCA. Further validation in larger cohorts is essential for establishing clinical utility.

Deep learning-based automated pipeline for blood vessel detection and distribution analysis in multiplexed prostate cancer images

Introduction: Prostate cancer is a highly heterogeneous disease, presenting varying levels of aggressiveness and response to treatment. Angiogenesis is one of the hallmarks of cancer, providing oxygen and nutrient supply to tumors. Micro vessel density has previously been correlated with higher Gleason score and poor prognosis. Manual segmentation of blood vessels (BVs) In microscopy images is challenging, time consuming and may be prone to inter-rater variabilities. In this study, an automated pipeline is presented for BV detection and distribution analysis in multiplexed prostate cancer images. Methods: A deep learning model was trained to segment BVs by combining CD31, CD34 and collagen IV images. In addition, the trained model was used to analyze the size and distribution patterns of BVs in relation to disease progression in a cohort of prostate cancer patients (N = 215). Results: The model was capable of accurately detecting and segmenting BVs, as compared to ground truth annotations provided by two reviewers. The precision (P), recall (R) and dice similarity coefficient (DSC) were equal to 0.93 (SD 0.04), 0.97 (SD 0.02) and 0.71 (SD 0.07) with respect to reviewer 1, and 0.95 (SD 0.05), 0.94 (SD 0.07) and 0.70 (SD 0.08) with respect to reviewer 2, respectively. BV count was significantly associated with 5-year recurrence (adjusted p = 0.0042), while both count and area of blood vessel were significantly associated with Gleason grade (adjusted p = 0.032 and 0.003 respectively). Discussion: The proposed methodology is anticipated to streamline and standardize BV analysis, offering additional insights into the biology of prostate cancer, with broad applicability to other cancers.

Deep neuromuscular block attenuates intra-abdominal pressure and inflammation and improves post-operative cognition in prostate cancer patients following robotic-assisted radical prostatectomy

BACKGROUND

Whether neuromuscular block (NMB) affects Intra-abdominal pressure (IAP) and cognition in Prostate cancer (PC) patients with Robotic-assisted laparoscopic radical prostatectomy (RALRP) remains unclear. Here we aimed to compare the effects of deep and moderate NMB on the IAP, inflammation, and cognition.

METHODS

The Moderate neuromuscular block (MNMB) group (N = 44) and Deep neuromuscular block (DNMB) group (N = 47) were recruited. Intra-abdominal pressure was adjusted to meet RALRP requirements. The expression of pro-inflammatory factors was measured by ELISA. MMSE scores were recorded before the operation, 1 day and 1 week after the operation.

RESULTS

Significant decreases in IAP (p < 0.001) and IL-1β, IL-6, TNF-a, and S-100β (p ≤ 0.01) expressions were found in the DNMB group. The MMSE score in the DNMB group was higher than that in the MNMB group on day one (p = 0.046). The incidence of nausea and vomiting was lower in the DNMB group than that in the MNMB group (p = 0.013).

CONCLUSIONS

DNMB reduces IAP and inflammation and improves post-operative cognitive functions in PC patients with RALRP.

Developing a Core Outcome Set for Assessing Clinical Safety Outcomes of Prostate Cancer in Clinical Trials of Traditional Chinese Medicine: Protocol for a Mixed Methods Study

BACKGROUND

Among the common malignant tumors in men worldwide, the incidence of prostate cancer ranks second to lung cancer. This disease will bring an economic burden to patients and their families and can reduce the quality of life of patients. Researchers have conducted numerous clinical trials on the efficacy and safety of different interventions in the treatment of prostate cancer with traditional Chinese medicine (TCM) combined with standard treatment regimens. However, the currently published clinical trials exhibit inconsistent and irregular reporting of outcome measures.

OBJECTIVE

The objective of this paper is to emphasize the need for a core outcome set (COS) to facilitate future prostate cancer research, aiming to improve the quality of trials and generate high-quality evidence.

METHODS

This mixed methods project has three phases, as follows: (1) a scoping review of the literature to identify outcomes that have been reported in clinical trials and systematic reviews of interventions involving TCM for the treatment of prostate cancer as well as a qualitative component using interviews to obtain the views of patients with prostate cancer, their families, and their caregivers who have a history of TCM treatment; (2) a Delphi survey among stakeholders to prioritize the core outcomes-Participants will include traditional Chinese and Western medicine clinicians in prostate cancer-related directions, nurses, and methodology experts who will participate in 2 rounds of the Delphi method expert consultation to score each outcome in the list of outcome indicators; and (3) a face-to-face consensus meeting to discuss and agree on the final COS for the application of TCM in the treatment of prostate cancer.

RESULTS

The protocol has been registered in PROSPERO (CRD42022356184) before the start of the review process, and we will initiate the review on August 1, 2023; results should be expected by September 1, 2023. The Delphi survey among stakeholders is expected to start in October 2023.

CONCLUSIONS

The development of a core outcome set for assessing clinical safety outcomes of prostate cancer in clinical trials of TCM will provide a significant first step to assist Chinese doctors, researchers, and policy makers.

TRIAL REGISTRATION

PROSPERO CRD42022356184; https://tinyurl.com/ysakz74r.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/46794.

Mobile health (mHealth) interventions in prostate cancer survivorship: a scoping review

PURPOSE

This scoping review explores the application of mHealth technology in prostate cancer (CaP) management along the survivorship continuum.

METHODS

The scoping review was conducted using the five-step framework developed by Arksey and O'Malley. Using predefined criteria, we screened citations from Embase, EBSCOHost, Cochrane Library, PubMed, ProQuest, SCOPUS, and Web of Science for primary studies published before December 2021. We selected studies that explored the application of mHealth technology in CaP management and survivorship. Evidence from 14 eligible studies was summarized using narrative synthesis.

RESULTS

Fourteen studies published between 2015 and 2021 were included. Ten mHealth apps were identified with only one still in use. Most apps were explored for their supportive care roles during radiotherapy (n = 9) and androgen deprivation therapy (ADT) (n = 1) treatment, mainly to assess outcomes (n = 1) and manage patient-reported symptoms (n = 5). One study deployed mHealth to facilitate recovery after surgery. Very few studies (n = 3) applied mHealth for lifestyle management (i.e., physical activity). Barriers to app usage included connectivity issues, end-user familiarity with the app, login hurdles, and time constraints. Facilitators of app usage included apps being downloaded for participants, devices provided for participants, and the ability to connect with providers through the platform.

CONCLUSIONS AND IMPLICATIONS FOR CANCER SURVIVORS

The improving survival rates from CaP suggest that men are now living longer with unfavorable treatment side effects such as reduced sexual functioning, pain, and fatigue. Hence, mHealth represents new hope in men's illness trajectory. However, current application in patients' care pathways remains poor, particularly in the active phase of CaP management. Efforts must be accelerated to explore individual and healthcare-level drivers of mHealth use. The feasibility and descriptive nature of current studies point to a lack of attention to actual implementation and scale-up issues in research considering mHealth application in CaP, hence accounting partly for the gap in research/practice.

Silibinin Radiosensitizes EGF Receptor-knockdown Prostate Cancer Cells by Attenuating DNA Repair Pathways

Emergence of radioresistance in prostate cancer (PCa) cells is a major obstacle in cancer therapy and contributes to the relapse of the disease. EGF receptor (EGFR) signaling plays an important role in the development of radioresistance. Herein, we have assessed the modulatory effects of silibinin on radiation-induced resistance via DNA repair pathways in EGFR-knockdown DU145 cells. shRNA-based silencing of EGFR was done in radioresistant human PCa DU145 cells and effects of ionizing radiation (IR) and silibinin were assessed using clonogenic and trypan blue assays. Furthermore, radiosensitizing effects of silibinin on PCa in context with EGFR were analyzed using flow cytometry, comet assay, and immunoblotting. Silibinin decreased the colony formation ability with an increased death of DU145 cells exposed to IR (5 Gray), with a concomitant decrease in Rad51 protein expression. Silibinin (25 μM) augmented the IR-induced cytotoxic effect in EGFR-knockdown PCa cells, along with induction of G2/M phase cell cycle arrest. Further, we studied homologous recombination (HR) and non-homologous end joining (NHEJ) pathways in silibinin-induced DNA double-strand breaks in EGFR-knockdown DU145 cells. Silibinin down-regulated the expression of Rad51 and DNA-dependent protein kinase proteins without any considerable effect on Ku70 and Ku80 in IR-exposed EGFR-knockdown PCa cells. The pro-survival signaling proteins, phospho-extracellular signal-regulated kinases (ERK)1/2, phospho-Akt and phospho-STAT3 were decreased by silibinin in EGFR-deficient PCa cells. These findings suggest a novel mechanism of silibinin-induced radiosensitization of PCa cells by targeting DNA repair pathways, HR and NHEJ, and suppressing the pro-survival signaling pathways, ERK1/2, Akt and STAT3, in EGFR-knockdown PCa cells.

Mental Health in Urologic Oncology

This article is a systematic review of mental health in urologic oncology patients with prostate cancer (PCa), bladder cancer (BC), renal cell carcinoma (RCC), testicular cancer (TC), or penile cancer (PeCa). For all pathologies, a focus on increasing quality of life post-treatment demonstrated a positive impact in reducing Mental Health Illness (MHI) prevalence. Cancer specific mental health care may be given to patients to reduce suicide risk in BC patients and sexual identify and masculinity counseling may improve mental health for TC or PeCa patients. In order to better accommodate patient’s mental health needs when undergoing GU cancer treatment, we recommend incorporation of mental health metrics such as questionnaires to assess early treatment of MHI, a greater emphasis on psychosocial support with the patient’s loved ones, peers, and healthcare team, alongside advising healthy habits such as exercise which has been shown to drastically reduce MHI incidence across all pathologies. We hope that these measures conducted by urologists and oncologists, alongside possible coordination with psychiatrists and psychologists for psychotherapy, psychopharmacology, and neuro-stimulation treatment modems may be helpful in the long term to reduce MHI incidence in urology oncology patients. Given the higher incidence of MHI in oncology patients and in the patient population after the Covid-19 pandemic, MHI awareness in the sphere of urologic oncologic treatment continues to be crucial when creating a collaborative treatment platform for patients.

A Novel Overall Survival Prediction Signature Based on Comprehensive Research in Prostate Cancer Bone Metastases

BACKGROUND

Prostate adenocarcinoma (PRAD)-related bone metastases are a leading source of morbidity and mortality; however, good diagnostic biomarkers are not known yet. The aim of this study was to identify biomarkers and prognostic indicators for the diagnosis and treatment of PRAD-associated bone metastases.

METHODS

By combining the data from The Cancer Genome Atlas(TCGA) and PRAD SU2C 2019, We performed a comprehensive analysis of the expression differences, biological functions, and interactions of genes associated with PRAD bone metastasis. Annotation, visualization, and integrated discovery were accomplished through the use of gene ontology enrichment and gene set enrichment analysis. The protein-protein interaction network was constructed using the STRING database, and the diagnostic value of prognostic genes was validated using receiver-operating-characteristic and Kaplan-Meier curves.

RESULTS

Six genes (DDX47, PRL17, AS3MT, KLRK1, ISLR, and S100A8) associated with PRAD bone metastases were identified; these had prognostic value as well. Among them, enrichment was observed for the biological processes extracellular matrix tissue, extracellular structural tissue, steroid hormone response, and cell oxidative detoxification. KEGG analysis revealed enrichment in interactions with extracellular matrix receptors, diseases including Parkinson's disease and dilated cardiomyopathy, and estrogen signaling pathways. The area under the curve values of 0.8938, 0.9885, and 0.979, obtained from time-dependent receiver-operating-characteristic curve analysis for 1, 3, and 5-year overall survival confirmed the good performance of the model under consideration. S100A8 expression was not detected in the normal prostate tissue but was detected in PRAD.

CONCLUSIONS

We identified ISLR as a potential biomarker for PRAD bone metastasis. Moreover, the genes identified to have prognostic value may act as therapeutic targets for PRAD bone metastasis.

Embryologic and hormonal contributors to prostate cancer in transgender women

Transgender women, who were assigned male at birth but identify as women, may take several steps to merge their physical and psychological identities, including gender-affirming surgeries and hormone therapy. With the presence of the mature prostate gland there persists a risk for malignant transformation in this population. The recognition by the medical community and society at large that transgender women are at risk of developing prostate cancer has recently been supported by investigative efforts. The slowly emerging clinical evidence suggests that the disease is likely to be more aggressive than in cisgender men, with 6 of 9 published cases discussing metastasis reporting metastatic disease on presentation. Currently the overall prevalence appears low, pointing to evolving awareness, educational status, socioeconomic status, and late presentation. This commentary focuses on exploring the factors contributing to the incidence of prostate cancer and the biochemical and endocrine mechanisms that lead to aggressive prostate tumor development in transgender women.

Prognostic role of 11C-choline PET/CT scan in patients with metastatic castrate resistant prostate cancer undergoing primary docetaxel chemotherapy

BACKGROUND

We sought to assess the prognostic utility of 11C-choline positron emission tomography/computed tomography (PET/CT) in patients with metastatic castrate resistant prostate cancer (mCRPC) undergoing primary docetaxel chemotherapy.

METHODS

We performed a single institution retrospective analysis of 77 mCRPC patients who were treated with 6 cycles of docetaxel chemotherapy, and who also underwent 11C-choline PET/CT scans at baseline (before chemotherapy), mid-course (after 3 cycles), and posttherapy (after 6 cycles). We evaluated treatment response based on percent change in blood pool-corrected maximum standardized uptake value (SUVmax) of the target lesion on PET/CT, as well as percent change in serum prostate specific antigen (PSA). Logistic regression analysis was used to identify factors associated with complete treatment response. Progression free survival (PFS) analysis was performed using log-rank test and shown on Kaplan-Meier plot.

RESULTS

Percent change in blood pool-corrected SUVmax on mid-course scan was a significant predictor of complete response (odds ratio [OR]: 0.98, 95% confidence interval [CI]: 0.96-0.99, p = .0003), whereas percent change in PSA was not (OR: 0.99, 95% CI: 0.99-1.01, p = .6025). 57 of 77 patients (74%) achieved ≥20% reduction in blood pool-corrected SUVmax on mid-course; these patients were 3.6 times more likely to achieve complete response after full 6 cycles of docetaxel chemotherapy, compared to patients with <20% reduction in blood pool-corrected SUVmax (OR: 3.56, 95% CI: 1.04-16.52, p = .0420). Median PFS in the complete response group was 35.1 months (95% CI: 26.0-52.7 months), compared to 9.4 months (95% CI: 6.9-13.0 months) in the incomplete response group (p = .0005).

CONCLUSIONS

Our study showed that mid-course and posttherapy 11C-choline PET/CT evaluation for mCRPC patients undergoing primary docetaxel chemotherapy can predict full course treatment response and PFS, respectively. 11C-choline PET/CT imaging may provide valuable prognostic information to guide treatment choices for patients with mCRPC.

Post Hoc Health-Related Quality of Life Analysis According to Response Among Patients with Prostate Cancer in the PROSELICA and FIRSTANA Studies

BACKGROUND

The phase III PROSELICA (NCT01308580) and FIRSTANA (NCT01308567) trials investigated taxane chemotherapy among men with postdocetaxel metastatic, castration-resistant prostate cancer (mCRPC) or chemotherapy-naïve mCRPC, respectively. We present a post hoc analysis of patient-reported health-related quality of life (HRQL) among patients with or without a clinical (pain, tumor, or prostate-specific antigen [PSA]) response.

MATERIALS AND METHODS

PROSELICA and FIRSTANA HRQL and pain data were collected and analyzed using protocol-defined Functional Assessment of Cancer Therapy-Prostate (FACT-P) and McGill-Melzack (Present Pain Intensity scale) questionnaires. Outcomes included definitive FACT-P Total Score (TS) improvements and longitudinal assessment of FACT-P TS.

RESULTS

In PROSELICA and FIRSTANA, the proportion of patients receiving taxane chemotherapy with a definitive FACT-P TS improvement was significantly higher among patients with versus without a pain or PSA response (pain: PROSELICA: 67% vs. 33.5%; p < .001; FIRSTANA: 75.2% vs. 45.8%; p < .001; PSA: PROSELICA: 50.3% vs. 34.2%; p < .001; FIRSTANA: 49.8% vs. 38.9%; p = .001). In PROSELICA, the proportion of patients receiving taxane chemotherapy with a definitive FACT-P TS improvement was significantly higher among patients with versus without a tumor response; the proportion was numerically higher in FIRSTANA (PROSELICA: 54.4% vs. 36.7%; p = .001; FIRSTANA: 50.6% vs. 45.3%). FACT-P TS was significantly improved or maintained for the majority of treatment cycles analyzed.

CONCLUSION

In PROSELICA and FIRSTANA, HRQL improvements were significantly higher among patients with a pain, tumor, or PSA response versus those without, with the exception of patients with a tumor response in FIRSTANA.

IMPLICATIONS FOR PRACTICE

Using data from the FIRSTANA and PROSELICA phase III clinical trials, this study demonstrated that patients with metastatic, castration-resistant prostate cancer (mCRPC) receiving docetaxel or cabazitaxel who exhibited a response (pain, tumor, prostate-specific antigen), often experienced significantly greater improvements in health-related quality of life (HRQL) compared with patients without a response. For patients with a pain response, significant HRQL improvements occurred early and were maintained. This study provides further insight into the impact of taxane chemotherapy on the HRQL of patients with mCRPC and allows for a better understanding of the relationship between treatment, response, and HRQL, supporting therapeutic decision making.

Antihormone treatment differentially regulates PSA secretion, PSMA expression and 68Ga-PSMA uptake in LNCaP cells

Background

In recent years, a variety of innovative therapeutics for castration-resistant prostate cancer have been developed, including novel anti-androgenic drugs, such as abiraterone or VPC-13566. Therapeutic monitoring of these pharmaceuticals is performed either by measuring PSA levels in serum or by imaging. PET using PSMA ligands labeled with Fluor-18 or Gallium-68 is the most sensitive and specific imaging modality for detection of metastases in advanced prostate cancer. To date, it remains unclear how PSMA expression is modulated by anti-hormonal treatment and how it correlates with PSA secretion.

Methods

We analyzed modulation of PSMA-mRNA and protein expression, ⁶⁸Ga–PSMA uptake and regulation of PSA secretion by abiraterone or VPC-13566 in LNCaP cells in vitro.

Results

We found that abiraterone and VPC-13566 upregulate PSMA protein and mRNA expression but block PSA secretion in LNCaP cells. Both anti-androgens also enhanced ⁶⁸Ga–PSMA uptake normalized by the number of cells, whereas abiraterone and VPC-13566 reduced ⁶⁸Ga–PSMA uptake in total LNCaP monolayers treated due to cell death.

Conclusion

Our data indicate that PSA secretion and PSMA expression are differentially regulated upon anti-androgen treatment. This finding might be important for the interpretation of ⁶⁸Ga–PSMA PET images in monitoring therapies with abiraterone and VPC-13566 in prostate cancer patients, but needs to be validated in vivo.

Postoperative imaging surveillance for hepatocellular carcinoma: How much is enough?

BACKGROUND

The objective of the current study was to define trends in postoperative surveillance imaging following liver-directed treatment of hepatocellular carcinoma (HCC), and characterize the impact of high-intensity surveillance on long-term survival.

METHODS

Patients who underwent liver- directed therapy for HCC between 2004 and 2016 were identified using the SEER-Medicare database. Trends in surveillance intensity over time, factors associated with high surveillance intensity and the impact of surveillance on long-term outcomes were examined.

RESULTS

Utilization of high-intensity surveillance abdominal imaging (≥6 scans over 2 years) following liver-directed therapy of HCC decreased over time (2004-2007: n = 130, 36.1% vs. 2008-2011: n = 181, 29.5% vs. 2012-2016: n = 111, 24.5%; p_trend  < 0.001). History of chronic viral hepatitis (hepatitis B: odds ratio [OR], 1.98; 95% confidence interval [CI]: 1.15-3.43; hepatitis C: OR, 1.79; 95% CI: 1.32-2.43), presence of regional (vs. local-only) disease (OR, 1.47; 95% CI: 1.09-1.98) and receipt of transplantation (OR, 2.23; 95% CI: 1.57-3.17) were associated with higher odds of high intensity surveillance. Intensity of surveillance imaging was not associated with long-term survival (5-year overall survival: low-intensity, 48.1% vs. high-intensity, 48.9%; hazards ratio, 0.94; 95% CI: 0.78-1.13).

CONCLUSION

Utilization of posttreatment surveillance imaging decreased over time following liver-directed therapy for HCC. While utilization of high-intensity screening varied by HCC procedure performed, intensity of surveillance had no effect on survival.

Quantification and Optimization of Standard-of-Care Therapy to Delay the Emergence of Resistant Bone Metastatic Prostate Cancer

BACKGROUND

Bone metastatic prostate cancer (BMPCa), despite the initial responsiveness to androgen deprivation therapy (ADT), inevitably becomes resistant. Recent clinical trials with upfront treatment of ADT combined with chemotherapy or novel hormonal therapies (NHTs) have extended overall patient survival. These results indicate that there is significant potential for the optimization of standard-of-care therapies to delay the emergence of progressive metastatic disease.

METHODS

Here, we used data extracted from human bone metastatic biopsies pre- and post-abiraterone acetate/prednisone to generate a mathematical model of bone metastatic prostate cancer that can unravel the treatment impact on disease progression. Intra-tumor heterogeneity in regard to ADT and chemotherapy resistance was derived from biopsy data at a cellular level, permitting the model to track the dynamics of resistant phenotypes in response to treatment from biological first-principles without relying on data fitting. These cellular data were mathematically correlated with a clinical proxy for tumor burden, utilizing prostate-specific antigen (PSA) production as an example.

RESULTS

Using this correlation, our model recapitulated the individual patient response to applied treatments in a separate and independent cohort of patients (n = 24), and was able to estimate the initial resistance to the ADT of each patient. Combined with an intervention-decision algorithm informed by patient-specific prediction of initial resistance, we propose to optimize the sequence of treatments for each patient with the goal of delaying the evolution of resistant disease and limit cancer cell growth, offering evidence for an improvement against retrospective data.

CONCLUSIONS

Our results show how minimal but widely available patient information can be used to model and track the progression of BMPCa in real time, offering a clinically relevant insight into the patient-specific evolutionary dynamics of the disease and suggesting new therapeutic options for intervention.

TRIAL REGISTRATION

NCT # 01953640.

FUNDING

Funded by an NCI U01 (NCI) U01CA202958-01 and a Moffitt Team Science Award. CCL and DB were partly funded by an NCI PSON U01 (U01CA244101). AA was partly funded by a Department of Defense Prostate Cancer Research Program (W81XWH-15-1-0184) fellowship. LC was partly funded by a postdoctoral fellowship (PF-13-175-01-CSM) from the American Cancer Society.

Annexin A1 promotes the nuclear localization of the epidermal growth factor receptor in castration-resistant prostate cancer

Epidermal growth factor receptor is a cancer driver whose nuclear localization has been associated with the progression of prostate cancer to the castration-resistant phenotype. Previous reports indicated a functional interaction between this receptor and the protein Annexin A1, which has also been associated with aggressive tumors. The molecular pathogenesis of castration-resistant prostate cancer remains largely unresolved, and herein we have demonstrated the correlation between the expression levels and localization of the epidermal growth factor receptor and Annexin A1 in prostate cancer samples and cell lines. Interestingly, a higher expression of both proteins was detected in castration-resistant prostate cancer cell lines and the strongest correlation was seen at the nuclear level. We verified that Annexin A1 interacts with the epidermal growth factor receptor, and by using prostate cancer cell lines knocked down for Annexin A1, we succeeded in demonstrating that Annexin A1 promotes the nuclear localization of epidermal growth factor receptor. Finally, we showed that Annexin A1 activates an autocrine signaling in castration-resistant prostate cells through the formyl peptide receptor 1. The inhibition of such signaling by Cyclosporin H inhibits the nuclear localization of epidermal growth factor receptor and its downstream signaling. The present work sheds light on the functional interaction between nuclear epidermal growth factor receptor and nuclear Annexin A1 in castration-resistant prostate cancer. Therefore, strategies to inhibit the nuclear localization of epidermal growth factor receptor through the suppression of the Annexin A1 autocrine loop could represent an important intervention strategy for castration-resistant prostate cancer.

RhoA/ROCK pathway inhibitor ameliorates erectile dysfunction induced by radiation therapy in rats

OBJECTIVES

Prostate cancer (PCa) treatment with radiation therapy (RT) has an excellent cure rate. However, Radiation-induced Erectile Dysfunction (RiED) is a common and irreversible toxicity impacting quality of life, and there is no FDA approved specific drug for RiED. We previously showed that prostate RT increased RhoA/ROCK signaling in the cavernous nerve (CN) and penile tissues, which may lead to RiED in rats. In this study, we investigated whether RhoA/ROCK pathway inhibition by a specific inhibitor called Hydroxyfasudil (HF) can improve RiED in our well-established rat model.

MATERIALS/METHODS

Male Sprague-Dawley rats were randomized to the following groups: sham-RT, HF-only, RT-only, and RT + HF. Rats were either exposed to a single dose of 25 Gy prostate-confined RT or a sham procedure. 10 mg/kg HF or normal saline was injected intraperitoneally. Erectile function was evaluated by intracavernosal pressure (ICP) and mean arterial pressure (MAP) measurements at week 14 post-RT. Cavernous nerve (CN) injury was evaluated by transmission electron microscopy (TEM), and penile tissue fibrosis by Masson trichrome staining (MT).

RESULTS

We have found that the HF treatment prior to RT showed significant (p < 0.001) improvement in ICP/MAP ratio, area under the curve, and maximum ICP value, compared to RT-alone rats. Furthermore, RT + HF treated rats exhibited increased CN myelination and decreased axonal atrophy, comparted to RT-only. HF treatment showed significantly decreased penile tissue fibrosis (p < 0.05) compared to RT-alone treated rats.

CONCLUSION

Our results provide the first preclinical evidence that targeting RhoA/ROCK pathway by HF may provide a novel therapeutic option for the treatment of RiED.

A Quality-adjusted Time Without Symptoms or Toxicity (Q-TWiST) Analysis of Nivolumab Versus Everolimus in Advanced Renal Cell Carcinoma (aRCC)

This study assessed the net health benefits of treatment with nivolumab versus everolimus among patients with advanced renal cell carcinoma by assessing the quality (ie, patient preferences) and quantity of survival (ie, time spent with significant toxicities, in progression, or before progression and without significant toxicities). Nivolumab resulted in a 3.3-month quality-adjusted survival gain versus everolimus that was statistically significant and clearly clinically meaningful.

68Ga-PSMA PET/CT for monitoring response to 177Lu-PSMA-617 radioligand therapy in patients with metastatic castration-resistant prostate cancer

PURPOSE

To evaluate the use of ⁶⁸Ga-PSMA PET/CT for monitoring response to ¹⁷⁷Lu-617 PSMA radioligand therapy in patients with metastatic castrate-resistant prostate cancer (mCRPC).

METHODS

Patients from the University Hospital Bonn and the University Hospital Aachen were retrospectively reviewed for this study. We included 48 patients with mCRPC who were treated with ¹⁷⁷Lu-PSMA-617 and whose records included ⁶⁸Ga-PSMA PET/CT imaging before the first and after the third or fourth treatment cycle. A treatment response based on ⁶⁸Ga-PSMA PET/CT was defined according to a modified version of the PERCIST criteria. A decline in PSA level of ≥50% was considered the reference standard. The sensitivity, specificity, positive and negative predictive values, and ROC curves were calculated, and patient survival times in relation to the PET results were also analysed.

RESULTS

⁶⁸Ga-PSMA PET/CT had a sensitivity of about 85% and a specificity of between 55% and 65%. The negative and positive predictive values ranged between 70% and 78%. The fitted ROC area was 0.70. The survival time was about 19.6 months in patients with a treatment response, while nonresponders had a survival time of about 15.9 months. However, this difference between the groups was not statistically significant.

CONCLUSION

Our results indicate that ⁶⁸Ga-PSMA PET/CT could be a useful tool for the evaluation of response to ¹⁷⁷Lu-PSMA-617 radioligand therapy within a theranostic framework.

Machine learning-based radiomic models to predict intensity-modulated radiation therapy response, Gleason score and stage in prostate cancer

OBJECTIVE

To develop different radiomic models based on the magnetic resonance imaging (MRI) radiomic features and machine learning methods to predict early intensity-modulated radiation therapy (IMRT) response, Gleason scores (GS) and prostate cancer (Pca) stages.

METHODS

Thirty-three Pca patients were included. All patients underwent pre- and post-IMRT T2-weighted (T2 W) and apparent diffusing coefficient (ADC) MRI. IMRT response was calculated in terms of changes in the ADC value, and patients were divided as responders and non-responders. A wide range of radiomic features from different feature sets were extracted from all T2 W and ADC images. Univariate radiomic analysis was performed to find highly correlated radiomic features with IMRT response, and a paired t test was used to find significant features between responders and non-responders. To find high predictive radiomic models, tenfold cross-validation as the criterion for feature selection and classification was applied on the pre-, post- and delta IMRT radiomic features, and area under the curve (AUC) of receiver operating characteristics was calculated as model performance value.

RESULTS

Of 33 patients, 15 patients (45%) were found as responders. Univariate analysis showed 20 highly correlated radiomic features with IMRT response (20 ADC and 20 T2). Two and fifteen T2 and ADC radiomic features were found as significant (P-value ≤ 0.05) features between responders and non-responders, respectively. Several cross-combined predictive radiomic models were obtained, and post-T2 radiomic models were found as high predictive models (AUC 0.632) followed by pre-ADC (AUC 0.626) and pre-T2 (AUC 0.61). For GS prediction, T2 W radiomic models were found as more predictive (mean AUC 0.739) rather than ADC models (mean AUC 0.70), while for stage prediction, ADC models had higher prediction performance (mean AUC 0.675).

CONCLUSIONS

Radiomic models developed by MR image features and machine learning approaches are noninvasive and easy methods for personalized prostate cancer diagnosis and therapy.

Passive-specific immunotherapy with monoclonal antibodies for prostate cancer: A systematic review

Introduction

Treatment of metastatic castration-resistant prostate cancer with conventional therapies is still not successful. Therefore, application of novel biological approaches such as immunotherapy, which appears to be more effective and less toxic, is necessary. Monoclonal antibodies against cancer specific antigens are a kind of immunotherapy that have been approved for specific types of cancer and are being investigated for prostate cancer as well. The aim of this review was to assess the effectiveness and safety of monoclonal antibodies for treatment of advanced prostate cancer.

Method

According to the search strategy stated in our systematic review protocol, Scopus, Medline, TRIP, CENTRAL, ProQuest, DART and OpenGrey databases were searched. Data collection and quality assessment were done independently by two authors and any disagreements between the collected data were resolved by a third author. A meta-analysis was not feasible as there was a considerable statistical heterogeneity among the trials. Hence, this review was limited to a narrative analysis of the included studies.

Results

We found 9756 references by applying search strategy in 4 databases of journal articles and 3 databases of grey literature. We then discarded 3957 duplicate citations using Endnote software and 5143 articles due to obvious irrelevancy of their topics in primary screening. In secondary screening of 656 fulltexts, we excluded 538 articles, and finally included 12 trials in this systematic review, updated on 23 June 2017. The overall quality of the studies was fair. In general, results of this systematic review show promising advances in the treatment of prostate cancer patients with monoclonal antibodies against prostate-specific antigens with regard to PSA/disease response. Some of the studies reported pain relief after treatment as well.

Conclusion

Currently, the role of immunotherapy in the treatment of advanced prostate cancer still remains debated. Although passive specific immunotherapy could be offered as a novel therapeutic option in the coming years, patients should be informed about the risks and benefits of this therapy. One of the obstacles in this review was the lack of adequate assessment of survival-related endpoints reported in the included studies. Our study provides support for further research in this field.

Effect of androgen deprivation and radiation therapy on MRI fiber tractography in prostate cancer: can we assess treatment response on imaging?

OBJECTIVE

To evaluate quantitative changes in Diffusion Tensor Magnetic Resonance Tractography in prostate cancer following androgen deprivation and radiation therapy.

METHODS

22 patients with elevated PSA and biopsy proven prostate carcinoma who underwent MRI of the prostate at 1.5 T with an endorectal coil were included. Group A) was the study group (n = 11), participants who underwent androgen deprivation and/or radiation therapy and group B) were Gleason-matched control group (n = 11) participants who did not undergo such therapy. Diffusion weighted images were used to generate three-dimensional (3D) map of fiber tracts from DTI. 3D regions of interest (ROI) were drawn over the tumor and healthy prostatic parenchyma in both groups to record tract number and tract density. Tumor region and normal parenchymal tract densities within each group were compared.

RESULTS

Mean tract density in the tumor region and normal parenchyma was 2.3 and 3.3 in study group (tract numbers: 116.6 and 170.2 respectively) and 1.6 and 2.7 in the control group respectively (tract numbers: 252.5 and 346.3 respectively). The difference between these values was statistically significant for the control group (p = 0.0018) but not for the study group (p = 0.11). The difference between the tract numbers of tumor and normal parenchyma appears to narrow following therapy.

CONCLUSION

The study demonstrated utility in using tractography as a biomarker in prostate cancer patients post treatment.

ADVANCES IN KNOWLEDGE

Quantitative DTI fiber tractography is a promising imaging biomarker to quantitatively assess treatment response in the setting of post-androgen deprivation and radiation therapy for prostate cancer.

Correlating blood-based DNA methylation markers and prostate cancer risk in African-American men

The objective of this work was to investigate the clinical significance of promoter gene DNA methylation changes in whole blood from African-American (AA) men with prostate cancer (PCa). We used high throughput pyrosequencing analysis to quantify percentage DNA methylation levels in a panel of 8 genes (RARβ2, TIMP3, SPARC, CDH13, HIN1, LINE1, CYB5R2 and DRD2) in blood DNA obtained from PCa and non-cancerous controls cases. Correlations of methylation status and various clinicopathological features were evaluated. Six genes tested achieved significant difference in DNA methylation levels between the PCa compared to control cases (P < 0.05). The TIMP3 loci demonstrated significant correlation of DNA methylation with age for all cases analyzed (p < 0.05). We observed an inverse correlation between CDH13 methylation (p = 0.045; r = -0.21) and serum vitamin D level whereas TIMP3 methylation (p = 0.021; r = -0.24) and DRD2 methylation (p = 0.056; r = -0.201) showed inverse correlation with supplementary vitamin D in the cancer cases. We also observed a direct correlation between methylation of RARβ2 (p = 0.0036; r = 0.293) and SPARC (p = 0.0134; r = 0.20) loci with PSA level in the controls but not the cancer cases. In addition, alcohol cases significantly correlated with higher RARβ2 methylation (p = 0.0314) in comparison with non-alcohol cases. Furthermore, we observed an inverse correlation of DRD2 methylation (p = 0.0349; r = -0.343) and Gleason score. Our data suggests that promoter methylation occurred more frequently in the blood of AA PCa and is associated with various clinicopathological features in AA men with PCa.

HZ08 suppresses RelB-activated MnSOD expression and enhances Radiosensitivity of prostate Cancer cells

Background

The development of radioresistance is one of main causes for therapeutic failure of prostate cancer (PCa). The present study aims to investigate the function and the related mechanism by which HZ08 sensitizes radiotherapeutic efficiency to treat aggressive PCa cells.

Methods

PCa cells were pretreated with HZ08 (6,7-dimethoxy-1-(3,4-dimethoxy) benzyl-2-(N-n-octyl-N′-cyano) guanyl-1,2,3,4-tetrahydroisoquinoline) and followed by ionizing radiation (IR) treatment. Cytotoxicity in the treated cells was analyzed to assess the radiosensitization capacity of HZ08 by flow cytometry, MTT and colony survival assays. The cellular levels of reactive oxygen species (ROS) and oxygen consumption rates (OCR) were measured using specific ROS detection probes and a Seahorse XF96 Analyzer, respectively. RelB binding to the NF-κB intronic enhancer region of the human SOD2 gene was determined using a ChIP assay. The levels of phosphorylation of PI3K, Akt and IKKα were quantified and further confirmed using a PI3K inhibitor. Finally, the synergistic effect of HZ08 on radiosensitization of PCa cells was validated using a mouse xenograft tumor model.

Results

HZ08 enhanced radiosensitivity of PCa cells through increasing ROS and declining mitochondrial respiration due to suppression of mitochondrial antioxidant enzyme MnSOD. Mechanistically, HZ08 appeared to inhibit PI3K/Akt/IKKα signaling axis, resulting in transcriptional repression of MnSOD expression by preventing RelB nuclear translocation.

Conclusions

HZ08 can serve as a useful radiosensitizing agent to improve radiotherapy for treating aggressive PCa cells with high level of constitutive RelB. The present study suggests a promising approach for enhancing radiotherapeutic efficiency to treat advanced PCa by inhibiting antioxidant defense function.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0849-5) contains supplementary material, which is available to authorized users.

MALAT1 silencing suppresses prostate cancer progression by upregulating miR-1 and downregulating KRAS

Background

Prostate cancer (PC) is the second leading cause of cancer-related deaths among men. Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) performed as an oncogene in multiple cancers including PC. However, the molecular mechanisms of MALAT1 implicated in PC progression have not been thoroughly elaborated.

Materials and methods

Reverse transcription-quantitative polymerase chain reaction assay was used to detect the expressions of MALAT1 and microRNA-1 (miR-1). Protein levels of cleaved poly (ADP-ribose) polymerase, cleaved caspase-3, BAX, bcl-2, and KRAS were determined using a western blot assay. Cell proliferation was assessed by colony formation and MTS assays. Cell migration capacity was examined by transwell migration assay (Corning Incorporated, Corning, NY, USA). Apoptosis rate was measured by flow cytometry via double staining of annexin V-FITC and propidium iodide. Luciferase and RNA immunoprecipitation assays were employed to explore the relationship among miR-1, MALAT1, and KRAS.

Results

MALAT1 expression was upregulated and miR-1 expression was downregulated in PC tissues and cell lines. MALAT1 knockdown inhibited cell proliferation and migration, and promoted cell apoptosis in androgen receptor-negative DU145 and PC3 cells. Molecular mechanism explorations disclosed that MALAT1 acted as a molecular sponge of miR-1 in DU145 cells. Moreover, miR-1 downregulation partly abrogated MALAT1 silencing-mediated anti-proliferative, antimigratory, and proapoptotic effects in DU145 and PC3 cells. Further investigation revealed that KRAS was a target of miR-1 in DU145 cells. MALAT1 acted as a competing endogenous RNA of miR-1, resulting in the increase of KRAS expression in DU145 and PC3 cells. Furthermore, miR-1 overexpression hampered proliferation and migration and promoted apoptosis in DU145 and PC3 cells, while these effects were markedly weakened following KRAS upregulation.

Conclusion

MALAT1 knockdown inhibited proliferation and migration and facilitated apoptosis by upregulating miR-1 and downregulating KRAS in androgen receptor-negative PCa cells, providing a new insight into the molecular basis of MALAT1 and a potential biomarker or therapeutic target for suppressing castration-resistant PC.

Detecting long non-coding RNA biomarkers in prostate cancer liquid biopsies: Hype or hope?

Prostate cancer is a heterogeneous malignancy, with clinical courses widely differing between indolent and aggressive lethal disease. This heterogeneity calls for a more personalized approach towards diagnosis, prognosis, treatment decision, monitoring and follow-up of patients. In this review, we discuss the possibilities and drawbacks of detecting RNA biomarkers in biological fluids to improve disease-specific survival and quality of life. In particular, we examine literature on long non-coding RNAs in blood and urine of prostate cancer patients. We thereby specifically focus on the need for standard operation procedures on many different levels, analytical validation, clinical validation, and assessment of clinical utility. We argue that thorough multi-step validation of putative biomarkers is necessary for successful translation into clinical prostate cancer care. Our recommendations may also prove useful to biomarker research in other cancers.

Spatial Heterogeneity and Evolutionary Dynamics Modulate Time to Recurrence in Continuous and Adaptive Cancer Therapies

Treatment of advanced cancers has benefited from new agents that supplement or bypass conventional therapies. However, even effective therapies fail as cancer cells deploy a wide range of resistance strategies. We propose that evolutionary dynamics ultimately determine survival and proliferation of resistant cells. Therefore, evolutionary strategies should be used with conventional therapies to delay or prevent resistance. Using an agent-based framework to model spatial competition among sensitive and resistant populations, we applied antiproliferative drug treatments to varying ratios of sensitive and resistant cells. We compared a continuous maximum-tolerated dose schedule with an adaptive schedule aimed at tumor control via competition between sensitive and resistant cells. Continuous treatment cured mostly sensitive tumors, but with any resistant cells, recurrence was inevitable. We identified two adaptive strategies that control heterogeneous tumors: dose modulation controls most tumors with less drug, while a more vacation-oriented schedule can control more invasive tumors. These findings offer potential modifications to treatment regimens that may improve outcomes and reduce resistance and recurrence.Significance: By using drug dose modulation or treatment vacations, adaptive therapy strategies control the emergence of tumor drug resistance by spatially suppressing less fit resistant populations in favor of treatment sensitive ones. Cancer Res; 78(8); 2127-39. ©2018 AACR.

Integrative (epi) Genomic Analysis to Predict Response to Androgen-Deprivation Therapy in Prostate Cancer

Therapeutic resistance is a central problem in clinical oncology. We have developed a systematic genome-wide computational methodology to allow prioritization of patients with favorable and poor therapeutic response. Our method, which integrates DNA methylation and mRNA expression data, uncovered a panel of 5 differentially methylated sites, which explain expression changes in their site-harboring genes, and demonstrated their ability to predict primary resistance to androgen-deprivation therapy (ADT) in the TCGA prostate cancer patient cohort (hazard ratio = 4.37). Furthermore, this panel was able to accurately predict response to ADT across independent prostate cancer cohorts and demonstrated that it was not affected by Gleason, age, or therapy subtypes. We propose that this panel could be utilized to prioritize patients who would benefit from ADT and patients at risk of resistance that should be offered an alternative regimen. Such approach holds a long-term objective to build an adaptable accurate platform for precision therapeutics.

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Integrative DNA methylation and mRNA expression analysis discovers a panel of markers of treatment resistance.

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This panel can predict patients with predisposition to resistance and those who would benefit from the therapy.

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Our approach is applicable to a wide range of therapeutic regimens.

Therapeutic resistance is an emerging clinical problem, with detrimental implications in oncology. Here, we propose a computational approach that integrates genomic and epigenomic data to prioritize patients at risk of treatment resistance. We have integrated DNA methylation and mRNA expression patient profiles, which defined a comprehensive panel of markers of therapeutic response. We have demonstrated that this panel predicts patients with predisposition to resistance and those who would benefit from the therapy. Even though driven by a critical need to investigate resistance to androgen-deprivation therapy in prostate cancer, our approch is applicable to a wide range of therapeutic regimens.

The prostate cancer focal therapy

Despite prostate cancer (PCa) is the leading form of non-cutaneous cancer in men, most patients with PCa die with disease rather than of the disease. Therefore, the risk of overtreatment should be considered by clinicians who have to distinguish between patients with high risk PCa (who would benefit from radical treatment) and patients who may be managed more conservatively, such as through active surveillance or emerging focal therapy (FT). The aim of FT is to eradicate clinically significant disease while protecting key genito-urinary structures and function from injury. While effectiveness studies comparing FT with conventional care options are still lacking, the rationale supporting FT relies on evidence-based advances such as the understanding of the index lesion's central role in the natural history of the PCa and the improvement of multiparametric magnetic resonance imaging (mpMRI) in the detection and risk stratification of PCa. In this literature review, we want to highlight the rationale for FT in PCa management and the current evidence on patient eligibility. Furthermore, we summarize the best imaging modalities to localize the target lesion, describe the current FT techniques in PCa, provide an update on their oncological outcomes and highlight trends for future research.

Tetrandrine (TET) Induces Death Receptors Apo Trail R1 (DR4) and Apo Trail R2 (DR5) and Sensitizes Prostate Cancer Cells to TRAIL-Induced Apoptosis

TNF-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in cancer cells, but not in normal cells; as such, it is a promising therapeutic agent. However, therapeutic resistance limits its clinical use in many malignancies, including prostate cancer. Strategies to sensitize cancer cells to TRAIL are urgently needed. We demonstrate here that small-molecule tetrandrine (TET) potentially sensitizes previously resistant (LNCaP and C4-2B cells) and mildly sensitive (PC3 cells) prostate cancer cells to TRAIL-induced apoptosis, and they do so by upregulating mRNA expression and protein levels of death receptors Apo Trail R1 (DR4) and Apo Trail R2 (DR5). Using shRNA knockdown, we show critical requirement of DR4 and DR5 in sensitization of prostate cancer cells to TRAIL. We show that double knockdown of DR4 and DR5 abrogated the apoptotic effects of TET and TRAIL. We also demonstrate that TET-induced DR4 and DR5 expression is independent of p53 status. Given that loss of p53 is associated with progression of prostate cancer to CRPC and NEPC, our results show that TET, by acting as a TRAIL-sensitizing agent in prostate cancer, could serve as a potential therapeutic agent in CRPC and NEPC, for which there is no cure to date. Mol Cancer Ther; 17(6); 1217-28. ©2018 AACR.

Recent Advances in the Generation of Antibody-Nanomaterial Conjugates

Targeted nanomedicines have significantly changed the way new therapeutics are designed to treat disease. Central to successful therapeutics is the ability to control the dynamics of protein-nanomaterial interactions to enhance the therapeutic effect of the nanomedicine. The aim of this review is to illustrate the diversity and versatility of the conjugation approaches involved in the synthesis of antibody-nanoparticle conjugates, and highlight significant new advances in the field of bioconjugation. Such nanomedicines have found utility as both advanced therapeutic agents, as well as more complex imaging contrast agents that can provide both anatomical and functional information of diseased tissue. While such conjugates show significant promise as next generation targeted nanomedicines, it is recognized that there are in fact no clinically approved targeted therapeutics on the market. This fact is reflected upon within this review, and attempts are made to draw some reasoning from the complexities associated with the bioconjugation chemistry approaches that are typically utilized. Present trends, as well as future directions of next generation targeted nanomedicines are also discussed.

Adjuvant versus salvage radiotherapy in prostate cancer: multi-institutional retrospective analysis of the Spanish RECAP database

PURPOSE

To compare adjuvant radiotherapy (ART) to salvage radiotherapy (SRT) after radical prostatectomy (RP) in a cohort of prostate cancer (PCa) patients. The primary aim was to comparatively assess 2- and 5-year biochemical relapse-free survival (BRFS). A secondary aim was to identify predictors of survival.

PATIENTS AND METHODS

Data were acquired from the RECAP database, a population-based prostate cancer registry in Spain. Inclusion criteria included RP (with or without lymphadenectomy) followed by ART or SRT. A total of 702 patients were analyzed. Pre-RT PSA values (>0.5 vs. ≤0.5 ng/ml), pathological stage (T1-2 vs. T3-4), post-surgical Gleason score (≤7 vs. 8-10), margin status (positive vs. negative), hormonal treatment (yes vs. no), and RT dose (≤66 Gy vs. >66 Gy) were evaluated to assess their impact on BRFS.

RESULTS

The mean patient age in the ART and SRT groups, respectively, was 64 years (range 42-82) and 64.8 years (range 42-82). Median follow-up after RT in the whole sample was 34 months (range 3-141). A total of 702 patients were included: 223 (31.8%) received ART and 479 (68.2%) SRT. BRFS rates (95% CI) in the ART and SRT groups at months 24 and 60 were, respectively: 98.1% (95.9-100.0%) vs. 91.2% (88.2-94.2%) and 84.5% (76.4-92.6%) vs. 74.0% (67.4-80.7%) (p = 0.004). No significant differences in OS were observed (p = 0.053). The following variables were significant predictors of biochemical recurrence in the SRT group: (1) positive surgical margin status (p = 0.049); (2) no hormonotherapy (p = 0.03); (3) total prostate dose ≤66 Gy (p = 0.004); and pre-RT PSA ≥0.5 ng/ml (p = 0.013).

CONCLUSIONS

This is the first nationwide study in Spain to evaluate a large cohort of PCa patients treated with RP followed by postoperative RT. ART yielded better 2- and 5-year BRFS rates, although OS was equivalent. These findings are consistent with most other published studies and support ART in patients with adverse prognostic characteristics after radical prostatectomy. Prospective trials are needed to compare immediate ART to early SRT to better determine their relative benefits.

Cavernous Nerve Injury by Radiation Therapy May Potentiate Erectile Dysfunction in Rats

PURPOSE/OBJECTIVES

Radiation-induced erectile-dysfunction (RiED) is one of the most common side effects of radiation therapy (RT) and significantly reduces the quality of life (QoL) of cancer patients. Approximately 50% of prostate cancer patients experience RiED within 3 to 5 years after completion of RT. A series of vascular, muscular, and neurogenic injuries after prostate RT lead to RiED; however, the precise role of RT-induced neurogenic injury in RiED has not been fully established. The cavernous nerves (CN) are postganglionic parasympathetic nerves located beside the prostate gland that assist in penile erection. This study was designed to investigate the role of CN injury, tissue damage, and altered signaling pathways in an RiED rat model.

METHODS AND MATERIALS

Male rats were exposed to a single dose of 25 Gy prostate-confined RT. Erectile function was evaluated by intracavernous pressure (ICP) measurements conducted both 9 and 14 weeks after RT. Neuronal injury was evaluated in the CN using quantitative polymerase chain reaction, conduction studies, transmission electron microscopy, and immunoblotting. Masson trichrome staining was performed to elucidate fibrosis level in penile tissues.

RESULTS

There were significant alterations in the ICP (P<.0001) of RT rats versus non-RT rats. TEM analysis showed decreased myelination, increased microvascular damage, and progressive axonal atrophy of the CN fibers after RT. Electrophysiologic analysis showed significant impairment of the CN conduction velocity after RT. RT also significantly increased RhoA/Rho-associated protein kinase 1 (ROCK1) mRNA and protein expression. In addition, penile tissue showed increased apoptosis and fibrosis 14 weeks after RT.

CONCLUSIONS

RT-induced CN injury may contribute to RiED; this is therefore a rationale for developing novel therapeutic strategies to mitigate CN and tissue damage. Moreover, further investigation of the RhoA/ROCK pathway's role in mitigating RiED is necessary.

Significantly altered expression of miR-511-3p and its target AKT3 has negative prognostic value in human prostate cancer

PURPOSE

In this study, we assessed the expression and functions of microRNA-511-3p (miR-511-3p) in human prostate cancer (CaP).

METHODS

Gene expressions of miR-511-3p in CaP cells and human CaP tumors were assessed by qPCR. In VCaP and PC3 cells, miR-511-3p was overexpressed by lentivirus. The functions of miR-511-3p upregulation in regulating in vitro cancer proliferation, migration and in vivo cancer growth were assessed by MTT, transwell and transplantation assays, respectively. Downstream target gene of miR-511-3p, AKT3, was verified by dual-luciferase activity and qPCR assays. AKT3 was then overexpressed in miR-511-3p-upregulated CaP cells to assess its functions in miR-511-3p-mediated cancer regulation.

RESULTS

MiR-511-3p is significantly downregulated in CaP cell lines, and human CaP tumors. MiR-511-3p was further downregulated in T3/T4-staged CaP tumors and closely correlated with shorter overall survival among CaP patients. In VCaP and PC3 cells, lentiviral-induced miR-511-3p upregulation was acting as a tumor suppressor by inhibiting in vitro cancer proliferation, migration and in vivo transplantation. Human AKT3 gene was confirmed to be the downstream target of miR-511-3p in CaP. In miR-511-3p-upregulated VCaP and PC3 cells, forced-overexpression of AKT3 reversed the tumor suppressive effects of miR-511-3p in CaP.

CONCLUSION

MiR-511-3p may serve as a prognostic factor and tumor suppressor in CaP, very likely through inverse regulation of its downstream target gene of AKT3.

The context of prostate cancer genomics in personalized medicine

Prostate cancer is one of the most common types of cancer in males. Heterogeneous genomic aberrations may lead to prostate cancer onset, progression and metastasis. This heterogeneity also contributes to the variety in cancer risk and outcomes, different drug responses and progression, observed between individual patients. Classical prognostic factors, including prostate-specific antigen, Gleason Score and clinical tumor staging, are not sufficient to portray the complexity of a clinically relevant cancer diagnosis, risk prognosis, treatment choice and therapy monitoring. There is a requirement for novel genetic biomarkers in order to understand the oncogenic heterogeneity in a patient-personalized clinical setting and to improve the efficacy of risk prognosis and treatment choice. A number of biomarkers and gene panels have been established from patient sample cohort studies. These previous studies have provided distinct information to the investigation of heterogeneous malignancy in prostate cancer, which aids in clinical decision-making. Biomarker-guided therapies may facilitate the effective selection of drugs during early treatment; therefore, are beneficial to the individual patient. A non-invasive approach allows for convenient and repeated sampling to screen for cancer and monitor treatment response without the requirement for invasive tissue biopsies. With the current availability of numerous advanced technologies, reliable detection of the minimal tumor residues present following treatment may become clinical practice and, therefore, inform further in the field of personalized medicine.

Feasibility of MRI-only treatment planning for proton therapy in brain and prostate cancers: Dose calculation accuracy in substitute CT images

PURPOSE

Magnetic resonance imaging (MRI) is increasingly used for radiotherapy target delineation, image guidance, and treatment response monitoring. Recent studies have shown that an entire external x-ray radiotherapy treatment planning (RTP) workflow for brain tumor or prostate cancer patients based only on MRI reference images is feasible. This study aims to show that a MRI-only based RTP workflow is also feasible for proton beam therapy plans generated in MRI-based substitute computed tomography (sCT) images of the head and the pelvis.

METHODS

The sCTs were constructed for ten prostate cancer and ten brain tumor patients primarily by transforming the intensity values of in-phase MR images to Hounsfield units (HUs) with a dual model HU conversion technique to enable heterogeneous tissue representation. HU conversion models for the pelvis were adopted from previous studies, further extended in this study also for head MRI by generating anatomical site-specific conversion models (a new training data set of ten other brain patients). This study also evaluated two other types of simplified sCT: dual bulk density (for bone and water) and homogeneous (water only). For every clinical case, intensity modulated proton therapy (IMPT) plans robustly optimized in standard planning CTs were calculated in sCT for evaluation, and vice versa. Overall dose agreement was evaluated using dose-volume histogram parameters and 3D gamma criteria.

RESULTS

In heterogeneous sCTs, the mean absolute errors in HUs were 34 (soft tissues: 13, bones: 92) and 42 (soft tissues: 9, bones: 97) in the head and in the pelvis, respectively. The maximum absolute dose differences relative to CT in the brain tumor clinical target volume (CTV) were 1.4% for heterogeneous sCT, 1.8% for dual bulk sCT, and 8.9% for homogenous sCT. The corresponding maximum differences in the prostate CTV were 0.6%, 1.2%, and 3.6%, respectively. The percentages of dose points in the head and pelvis passing 1% and 1 mm gamma index criteria were over 91%, 85%, and 38% with heterogeneous, dual bulk, and homogeneous sCTs, respectively. There were no significant changes to gamma index pass rates for IMPT plans first optimized in CT and then calculated in heterogeneous sCT versus IMPT plans first optimized in heterogeneous sCT and then calculated on standard CT.

CONCLUSIONS

This study demonstrates that proton therapy dose calculations on heterogeneous sCTs are in good agreement with plans generated with standard planning CT. An MRI-only based RTP workflow is feasible in IMPT for brain tumors and prostate cancers.

Clinical Utility of Gallium-68 PSMA PET/CT Scan for Prostate Cancer

BACKGROUND

Prostate cancer is biologically and clinically a heterogeneous disease that makes imaging evaluation challenging. One of the important challenges in this cancer is to detect recurrent disease. Biochemical response using Prostate Specific Antigen (PSA) and Imaging using several PET tracers have poor sensitivity and specificity. Therefore, we analyse the role of Ga68-PSMA (Prostate Specific Membrane Antigen) imaging in prostate cancer, which is a new PET tracer.

METHODS

In this study, we evaluated PET scans of 262 patients with diagnosis of prostate cancer. These patients were scanned using Ga68-PSMA for either staging or response evaluation.

RESULTS

336 PSMA scans were performed. Ga68-PSMA scan resulted in the detection of extra-prostatic disease in 53.2% of cases when done at baseline before commencing any treatment. The sensitivity of Ga68-PSMA at baseline with histopathological diagnosis was 95% with 95% CI ranging from 86% to 98%. The positive predictive value was high at 98% with 95% CI ranging from 91% to 99%. In 26 (10%) patients who had surgical castration, Ga68-PSMA scan was able to detect disease progression / castration resistance in 100% of cases. The outcome of castration-resistant prostate cancer was compared with other cases where castration was not done. In those who did not undergo castration, there was a significantly better response by hormone therapy (p = 0.03) and radiotherapy (p = 0.01) on Ga68-PSMA. The sensitivity of Ga68-PSMA response with biochemical response was 66.7% with 95% CI ranging between 46 %- 82.7%. Ga68-PSMA response did not correlate with biochemical response.

CONCLUSION

Ga68-PSMA has good sensitivity for diagnosis, staging, restaging, evaluation of therapy response and prognostication in prostate cancer.

Mangiferin functionalized radioactive gold nanoparticles (MGF-198AuNPs) in prostate tumor therapy: green nanotechnology for production, in vivo tumor retention and evaluation of therapeutic efficacy

We report here production of MGF-¹⁹⁸AuNPs and its application for prostate tumor therapy.

Prostate brachytherapy in Ghana: our initial experience

Purpose

This study presents the experience of a brachytherapy team in Ghana with a focus on technology transfer and outcome. The team was initially proctored by experienced physicians from Europe and South Africa.

Material and methods

A total of 90 consecutive patients underwent either brachytherapy alone or brachytherapy in combination with external beam radiotherapy for prostate carcinoma between July 2008 and February 2014 at Korle Bu Teaching Hospital, Accra, Ghana. Patients were classified as low-risk, intermediate, and high-risk according to the National Comprehensive Cancer Network (NCCN) criteria. All low-risk and some intermediate risk group patients were treated with seed implantation alone. Some intermediate and all high-risk group patients received brachytherapy combined with external beam radiotherapy.

Results

The median patient age was 64.0 years (range 46-78 years). The median follow-up was 58 months (range 18-74 months). Twelve patients experienced biochemical failure including one patient who had evidence of metastatic disease and died of prostate cancer. Freedom from biochemical failure rates for low, intermediate, and high-risk cases were 95.4%, 90.9%, and 70.8%, respectively. Clinical parameters predictive of biochemical outcome included: clinical stage, Gleason score, and risk group. Pre-treatment prostate specific antigen (PSA) was not a statistically significant predictor of biochemical failure. Sixty-nine patients (76.6%) experienced grade 1 urinary symptoms in the form of frequency, urgency, and poor stream. These symptoms were mostly self-limiting. Four patients needed catheterization for urinary retention (grade 2). One patient developed a recto urethral fistula (grade 3) following banding for hemorrhoids.

Conclusions

Our results compare favorably with those reported by other institutions with more extensive experience. We believe therefore that, interstitial permanent brachytherapy can be safely and effectively performed in a resource challenged environment if adequate training and proctoring is provided.

Inoculated Cell Density as a Determinant Factor of the Growth Dynamics and Metastatic Efficiency of a Breast Cancer Murine Model

4T1 metastatic breast cancer model have been widely used to study stage IV human breast cancer. However, the frequent inoculation of a large number of cells, gives rise to fast growing tumors, as well as to a surprisingly low metastatic take rate. The present work aimed at establishing the conditions enabling high metastatic take rate of the triple-negative murine 4T1 syngeneic breast cancer model. An 87% 4T1 tumor incidence was observed when as few as 500 cancer cells were implanted. 4T1 cancer cells colonized primarily the lungs with 100% efficiency, and distant lesions were also commonly identified in the mesentery and pancreas. The drastic reduction of the number of inoculated cells resulted in increased tumor doubling times and decreased specific growth rates, following a Gompertzian tumor expansion. The established conditions for the 4T1 mouse model were further validated in a therapeutic study with peguilated liposomal doxorubicin, in clinical used in the setting of metastatic breast cancer. Inoculated cell density was proven to be a key methodological aspect towards the reproducible development of macrometastases in the 4T1 mouse model and a more reliable pre-clinical assessment of antimetastatic therapies.

MicroRNA Theranostics in Prostate Cancer Precision Medicine

BACKGROUND

Prostate cancer is the second most frequently diagnosed cancer in men worldwide. Theranostics, a combination of diagnostics and therapeutics, is an emerging concept in the field of precision medicine, and microRNAs (miRNAs) are predictive pioneers in this area.

CONTENT

miRNAs are small endogenous noncoding RNA molecules that regulate gene expression posttranscriptionally by targeting messenger RNAs. More than 60% of all protein coding genes are controlled by miRNAs, which makes them powerful regulators of the different cellular processes involved in the pathogenesis of various types of cancer, including prostate cancer. Growing evidence indicates the differential expression of miRNAs in tumor tissues. In addition, miRNAs in body fluids, known as circulating miRNAs, are present in remarkably stable forms and their alteration in prostate cancer has been well documented. Circulating miRNAs are known to originate from tumor tissues, thereby enabling intercellular communication via carriers to promote tumorigenesis and malignancy. In addition, fueled by recent advances, the use of miRNA-based anticancer therapies has been proposed with the onset of early phase clinical trials to assess the therapeutic efficacy of miRNAs.

SUMMARY

In this review, we summarize the theranostic utility of miRNAs and outline their diagnostic and prognostic potential in prostate cancer. In addition, we discuss the current detection methodologies and emerging innovative strategies for the detection of miRNAs in body fluids and tumor tissues in the clinical setting. We also provide insight into the current and future therapeutic potential of miRNAs in prostate cancer.

Downregulated expression of miRNA-149 promotes apoptosis in side population cells sorted from the TSU prostate cancer cell line

The objective of the present study was to identify prostate cancer stem cells and determine the effects of modulating specific miRNAs on prostate CSC proliferation and apoptosis. We applied flow cytometry sorting of side population cells to cultures of prostate cancer cell lines (TSU, DU145, PC-3 and LNCaP). The proportion of SP cells in the TSU line was 1.60±0.40% (mean ± SD), while that of the DU145, PC-3 and LNCaP lines was 0.60±0.05, 0.80±0.05 and 0.60±0.20%, respectively. Because the proportion of SP cells derived from TSU cells is greater, these cells were selected to sort side population cells and non-side population cells. The stem-like properties of SP cells had been identified by in vivo and in vitro experiments, and the related study was published. RNA was extracted from the SP cells and non-SP cells and analyzed using miRNA microarray technology. Fifty-three miRNAs with significant differences in their expression were detected in total. Furthermore, 20 of these miRNAs were validated by qPCR. We found that hsa-miR‑149 expression in SP cells and non-SP cells was significantly different; hsa-miR-149 was significantly upregulated in SP cells. By constructing a vector for lentiviral infection, we found that the downregulation of hsa-miR-149 leads to a reduction in proliferation, an increase in apoptosis, and a significant reduction in the colony formation potential, thus, inhibiting tumor growth in vivo of SP cells from the TSU cell line. The present study will provide new avenues toward understanding the function of prostate cancer stem cells (PCSCs) in tumorigenicity and metastasis.

Antiproliferative effect of a synthetic aptamer mimicking androgen response elements in the LNCaP cell line

Prostate cancer usually develops to a hormone-refractory state that is irresponsive to conventional therapeutic approaches. Therefore, new methods for treating aggressive prostate cancer are under development. Because of the importance of androgen receptors (ARs) in the development of the hormone-refractory state and AR mechanism of action, this study was designed. A single-stranded DNA as an aptamer was designed that could mimic the hormone response element (HRE). The LNCaP cells as an AR-rich model were divided into three sets of triplicate groups: the test group was transfected with Aptamer Mimicking HRE (AMH), Mock received only transfection reagents (mock) and a negative control. All three sets received 0, 10 and 100 nM of dehydroepiandrosterone (DHEA) separately. Data analysis showed hormone dependency of LNCaP cells in the negative control group upon treatment with 10 and 100 nM DHEA (compared with cells left untreated (P=0.001)). Transfection of AMH resulted in significant reduction of proliferation in the test group when compared with the negative control group with 10 (P=0.001) or 100 nM DHEA (P=0.02). AMH can form a hairpin structure at 37 °C and mimic the genomic HRE. Hence, it is capable of effectively competing with genomic HRE and interrupting the androgen signaling pathway in a prostate cancer cell line (LNCaP).

MicroRNA-495 Regulates Migration and Invasion in Prostate Cancer Cells Via Targeting Akt and mTOR Signaling

Abnormal microRNA (miR) expressions were implicated in prostate cancer progression. We identified a novel miR-495, which was downregulated in prostate cancer, but not normal prostate cell lines. MiR-495 directly targeted the 3'-UTR of Akt and mTOR mRNAs. Expression of miR-495 in prostate cancer cells significantly downregulated Akt and mTOR, which further inhibited cancer cell proliferation, migration, and invasion in vitro. Function of miR-495 in vivo was examined in mouse xenograft model and was found to significantly inhibit the growth of tumors, mediated by repressing Akt and mTOR. Our report supported miR-495 as a novel tumor suppressor microRNA in prostate cancer.

Molecular mechanisms of curcumin and its semisynthetic analogues in prostate cancer prevention and treatment

Primary prostate cancer, also known as prostate adenocarcinoma (PCa), is a devastating cancer in men worldwide. Europe and developing countries of Asia have fewer reported cases of prostate cancer compared to increasing cases in the United States with higher incidence in Black men. Risk factors associated with prostate cancer are aging, genetics, lifestyle, high body mass index as well as carcinogenic exposure to carbon-containing fuels, tobacco, and charbroiled meats. Hormone therapy and radical prostatectomy are commonly implemented treatments. The >20.000 prostate cancer deaths of 2013 suggest that there exists a need for enhanced chemopreventive and therapeutic agents for prostate cancer treatment. Fruits, vegetables, and red wines contain high levels of polyphenolic levels. Consumption of these products may provide chemoprevetion of PCa. Curcumin, the major compound from the turmeric rhizome Curcuma longa has long been used for medicinal purposes as an antiseptic and wound healing. This review focuses on curcumin's therapeutic effectiveness in vitro and in vivo in prostate cancer models. The review will highlight the mechanisms of actions of curcumin in the signaling pathways of prostate cancer.

TRAIL-coated leukocytes that prevent the bloodborne metastasis of prostate cancer

Prostate cancer, once it has progressed from its local to metastatic form, is a disease with poor prognosis and limited treatment options. Here we demonstrate an approach using nanoscale liposomes conjugated with E-selectin adhesion protein and Apo2L/TRAIL (TNF-related apoptosis-inducing ligand) apoptosis ligand that attach to the surface of leukocytes and rapidly clear viable cancer cells from circulating blood in the living mouse. For the first time, it is shown that such an approach can be used to prevent the spontaneous formation and growth of metastatic tumors in an orthotopic xenograft model of prostate cancer, by greatly reducing the number of circulating tumor cells. We conclude that the use of circulating leukocytes as a carrier for the anti-cancer protein TRAIL could be an effective tool to directly target circulating tumor cells for the prevention of prostate cancer metastasis, and potentially other cancers that spread through the bloodstream.