Strategy For Prostate Cancer Research Articles

Development of Novel Inhibitors Targeting the D-Box of the DNA Binding Domain of Androgen Receptor.

The inhibition of the androgen receptor (AR) is an established strategy in prostate cancer (PCa) treatment until drug resistance develops either through mutations in the ligand-binding domain (LBD) portion of the receptor or its deletion. We previously identified a druggable pocket on the DNA binding domain (DBD) dimerization surface of the AR and reported several potent inhibitors that effectively disrupted DBD-DBD interactions and consequently demonstrated certain antineoplastic activity. Here we describe further development of small molecule inhibitors of AR DBD dimerization and provide their broad biological characterization. The developed compounds demonstrate improved activity in the mammalian two-hybrid assay, enhanced inhibition of AR-V7 transcriptional activity, and improved microsomal stability. These findings position us for the development of AR inhibitors with entirely novel mechanisms of action that would bypass most forms of PCa treatment resistance, including the truncation of the LBD of the AR.

Preclinical Models in Prostate Cancer: Resistance to AR Targeting Therapies in Prostate Cancer.

Prostate cancer is an androgen-driven tumor. Different prostate cancer therapies consequently focus on blocking the androgen receptor pathway. Clinical studies reported tumor resistance mechanisms by reactivating and bypassing the androgen pathway. Preclinical models allowed the identification, confirmation, and thorough study of these pathways. This review looks into the current and future role of preclinical models to understand resistance to androgen receptor-targeted therapies. Increasing knowledge on this resistance will greatly improve insights into tumor pathophysiology and future treatment strategies in prostate cancer.

Clinical significance of STEAP1 extracellular vesicles in prostate cancer

BackgroundExtracellular vesicles (EVs) are cell-derived lipid bilayer enclosed structures shed from the plasma membrane by all cell types. Evidence of EV presence in biological fluids has led to considerable efforts focused on identifying their cargo and determining their utility as a non-invasive diagnostic platform for cancer. In this study, we identify circulating STEAP1 (six-transmembrane epithelial antigen of the prostate 1)-positive EVs in the plasma of healthy males and prostate cancer patients and evaluate its diagnostic and prognostic significance.MethodsSTEAP1 was identified on EVs in prostate cancer patient plasma. EVs were validated using electron microscopy, Western blot, nanoparticle tracking analysis, and nanoscale flow cytometry. STEAP1-positive EVs were quantified for 121 males with prostate cancer and 55 healthy age-matched control males. An evaluation of STEAP1 in prostate cancer tissue was also performed using established prostate cancer cohort data (TCGA, MSKCC, and SU2C/PCF Dream Team).ResultsEvaluation of STEAP1-positive EVs by nanoscale flow cytometry identified a significant increase in prostate cancer patient plasma compared to healthy males. However, no association was found between total STEAP1 EV levels and disease recurrence or overall survival. Cohort data from prostate cancer tissue also found STEAP1 to be elevated in prostate cancer while no significant association with recurrence or overall survival was identified.ConclusionsSTEAP1 is known to be enriched on the cells of the prostate with potential clinical significance in prostate cancer. Our results identify and quantitate STEAP1-positive EVs in plasma and provide rationale for a STEAP1 EV-based liquid biopsy as a diagnostic strategy in prostate cancer.

A second opinion pathology review improves the diagnostic concordance between prostate cancer biopsy and radical prostatectomy specimens.

Objectives:The Gleason scoring system is an essential tool for determining the treatment strategy in prostate cancer (PCa). However, the Gleason grade group (GGG) often differs between needle-core biopsy (NCB) and radical prostatectomy (RP) specimens. We investigated the diagnostic value of a second opinion pathology review using NCB specimens in PCa.Materials and Methods:We retrospectively evaluated 882 patients who underwent robot-assisted RP from January 2012 to September 2019. Of these, patients whose original biopsy specimens were obtained from another hospital and reviewed by the urological pathology expert at our institution were included in the study. Patients who received neoadjuvant hormonal therapy were excluded from the study. Weighted kappa (k) coefficients were used to evaluate the diagnostic accuracy of each review.Results:A total of 497 patients were included in this study. Substantial agreement (weighted k = 0.783) in the GGG between initial- and second-opinion diagnoses based on NCB specimens was observed in 310 cases (62.4%). Although diagnoses based on a single opinion showed moderate agreement with the GGG of RP specimens (initial: 35.2%, weighted k = 0.522; second opinion; 38.8%, weighted k = 0.560), matching initial and second opinion diagnoses improved the concordance (42.9%, 133/310 cases) to substantial agreement (weighted k = 0.626).Conclusions:A second opinion of PCa pathology helps to improve the diagnostic accuracy of NCB specimens. However, over half of diagnoses that matched between the initial and second opinions differed from the diagnosis of RP specimens.

The Utilization of Poly(2-ethyl-2-oxazoline)-b-Poly(ε-caprolactone) Ellipsoidal Particles for Intracellular BIKDDA Delivery to Prostate Cancer.

Prostate cancer is the most common cancer, which is about 15-20% among male cancers worldwide. As most common strategies such as radiotherapy, chemotherapy, or surgery alone can be unsuccessful in the treatment of prostate cancer, this study aims to develop a new approach to deliver newly generated proapoptotic gene, BIKDDA, to androgen independent prostate cancer cells, 22RV1, using new generation nanocarriers called ellipsoids. As far as it is known, this is the first study that assesses the ability of proapoptotic gene BIKDDA to induce apoptosis in prostate cancer cell. BIKDDA encapsulating PEtOx-b-PCL-based ellipsoids are fabricated by solvent-switch method, and their morphology, size, and BIKDDA content are characterized. Gene delivery efficiency of BIKDDA loaded PEtOx-b-PCL ellipsoids is demonstrated by analysis of BIK mRNA expression with real-time PCR. The apoptotic effect of PEtOx-b-PCL ellipsoids loaded with BIKDDA (EPs-BIKDDA) on 22RV1 is shown by Annexin V staining. The obtained results demonstrate that the treatment of 22RV1 cells with EPs-BIKDDA can significantly increase BIK mRNA levels by 4.5-fold leading to cell death. This study not only represents BIKDDA as a potential therapeutic strategy in prostate cancer but also the capacity of ellipsoids as promising in vivo gene delivery vehicles.

Variation in adjuvant and early salvage radiotherapy after robot-assisted radical prostatectomy for prostate cancer: a population-based cohort study

Purpose: The primary aim of the study was to assess the association between having a radiotherapy (RT) department on-site at the surgical centre and the performed postoperative treatment strategy for prostate cancer (PCa) patients. According to the current international guidelines, adjuvant radiotherapy (ART) or a regular prostate-specific antigen (PSA)-based follow-up with (early) salvage radiotherapy ((e)SRT) if needed is recommended in case of adverse pathological characteristics.Material and methods: Prospective data on consecutive robot-assisted radical prostatectomy (RARP) patients in Belgium from 2009 to 2016 were identified in the Belgian Robotic-Assisted-Laparoscopic-Prostatectomy (Be-RALP) database. Multivariable regression was used to evaluate patient- and facility-related factors associated with postoperative radiation treatment.Results: 2072 patients undergoing a RARP, suffering at least one of the following adverse pathological features, i.e., extracapsular extension (ECE), seminal vesicle invasion (SVI) or positive section margins (PSM), and with registered follow-up until 24 months were enrolled. After RARP, ART was applied to 9.1% and (e)SRT to 12.6% of the patients. Multivariable analysis demonstrated that patients were more likely to receive ART or (e)SRT if they were operated in a hospital with a RT department on-site (odds ratio, ART: 1.49 [1.07-2.07]; (e)SRT: 1.55 [1.16-2.06]). Furthermore, the presence of higher tumour category (T-category) and/or PSM on final pathology was associated with a higher chance of getting ART and (e)SRT (p < .01).Conclusion: Variations in ART and (e)SRT are not only driven by patient-related characteristics. In our nationwide cohort, the availability of a RT department on-site at the surgical centre was found to be an independent predictor for ART and (e)SRT, with a 1.5 times higher odds of receiving postoperative RT during the first 24 months after surgery.

Targeting the ERG oncogene with splice-switching oligonucleotides as a novel therapeutic strategy in prostate cancer

BackgroundThe ERG oncogene, a member of the ETS family of transcription factor encoding genes, is a genetic driver of prostate cancer. It is activated through a fusion with the androgen-responsive TMPRSS2 promoter in 50% of cases. There is therefore significant interest in developing novel therapeutic agents that target ERG. We have taken an antisense approach and designed morpholino-based oligonucleotides that target ERG by inducing skipping of its constitutive exon 4.MethodsWe designed antisense morpholino oligonucleotides (splice-switching oligonucleotides, SSOs) that target both the 5′ and 3′ splice sites of ERG’s exon 4. We tested their efficacy in terms of inducing exon 4 skipping in two ERG-positive cell lines, VCaP prostate cancer cells and MG63 osteosarcoma cells. We measured their effect on cell proliferation, migration and apoptosis. We also tested their effect on xenograft tumour growth in mice and on ERG protein expression in a human prostate cancer radical prostatectomy sample ex vivo.ResultsIn VCaP cells, both SSOs were effective at inducing exon 4 skipping, which resulted in a reduction of overall ERG protein levels up to 96 h following a single transfection. SSO-induced ERG reduction decreased cell proliferation, cell migration and significantly increased apoptosis. We observed a concomitant reduction in protein levels for cyclin D1, c-Myc and the Wnt signalling pathway member β-catenin as well as a marker of activated Wnt signalling, p-LRP6. We tested the 3′ splice site SSO in MG63 xenografts in mice and observed a reduction in tumour growth. We also demonstrated that the 3′ splice site SSO caused a reduction in ERG expression in a patient-derived prostate tumour tissue cultured ex vivo.ConclusionsWe have successfully designed and tested morpholino-based SSOs that cause a marked reduction in ERG expression, resulting in decreased cell proliferation, a reduced migratory phenotype and increased apoptosis. Our initial tests on mouse xenografts and a human prostate cancer radical prostatectomy specimen indicate that SSOs can be effective for oncogene targeting in vivo. As such, this study encourages further in vivo therapeutic studies using SSOs targeting the ERG oncogene.

Focal therapy, time to join the multi-disciplinary team discussion?

Organ preserving management is common place in renal cancer, breast cancer and many other solid organ tumours. Current strategies in managing intermediate risk prostate cancer include either whole gland treatment, in the form of radical radiotherapy or radical prostatectomy, or active surveillance. The former is associated with significant post-treatment functional morbidity, whilst the latter associated with the burden of surveillance activity and patient anxiety. Focal therapy would logically fit as a middle ground for suitable patients in whom treatment would be recommended, but where much better functional outcomes may be possible. Ideally this comes without restricting the successful prevention of harm from the cancer. Historically limitations in developing tissue preserving focal therapy strategies in prostate cancer, were due to inaccuracies in tumour characterisation prior to treatment and during follow up. Consequently for example many patients undergoing an active surveillance strategy were being upgraded and upstaged within a short period. Recently high level evidence supporting the use of MRI and targeted biopsies, in particular the PROMIS and PRECISION trials have strengthened clinician confidence in accurate disease characterisation, thus making focal therapy to become a more feasible management option. With improved diagnostic strategies and the publication of reassuring medium term oncological and functional outcomes after focal therapy for intermediate risk prostate cancer, has the time come to require consideration of focal therapy within our multi-disciplinary team (MDT) meetings and with patients? In this review we will consider patient selection and the evidence for the various focal ablation options as well as the surveillance of these patients after treatment. The forthcoming trials to determine comparative effectiveness will be discussed.

A new strategy for prostate cancer.

A new strategy for prostate cancer.

Abstract 2360: Targeting IL-4R alpha on tumor-associated macrophages as a therapeutic strategy for prostate cancer

Abstract Prostate cancer tumor growth and disease progression are highly influenced by non-cancerous host cells within the tumor microenvironment including immune cells. High prevalence of tumor-associated macrophages (TAMs) in tumor biopsies is associated with poorer outcomes. TAMs comprise as much as 50 percent of prostate cancer tumors making them an abundant and critical target for treating prostate cancer. Macrophages adopt different functions in response to signaling molecules in their environment. The majority of prostate cancer TAMs resemble alternatively-activated M2 macrophages which, in healthy individuals, are primarily involved in wound healing. M2 TAMs behave similarly to wound-healing M2s by promoting cancer progression and immune suppression. Macrophages are converted to M2s when the signaling molecules interleukin-4 (IL-4) or IL-13 bind IL-4 Receptor Type I or II. Both of these receptor complexes contain the IL-4 receptor alpha subunit and signal through STAT6 to regulate downstream gene transcription and conversion to M2. Due to the central role of IL-4R alpha in tumor-promoting M2s, we hypothesize that disrupting IL-4R alpha signaling will undermine the tumor-promoting capabilities of M2-like TAMs. Using human macrophages cultured in vitro, we detect IL-4R alpha expression in non-malignant human macrophages by qPCR and immunoblot, critical data that is absent in the current literature. Additionally, using the FDA-approved antibody dupilumab, we show that antagonizing IL-4R alpha prevents STAT6 phosphorylation both before and after macrophages have been converted to M2s. Additionally, we show that dupilumab mitigates the M2 characteristics of these macrophages by nanostring analysis of M2-associated genes and ELISA of immunosuppressive cytokines. These data provide evidence that targeting IL-4R alpha on human macrophages impairs tumor-promoting M2 functions. To assess IL-4R alpha expression on TAMs in vivo, we used the HiMyc and TRAMP transgenic mouse models. These mice develop spontaneous prostate cancer tumors and are more accurate representations of the primary tumor microenvironment than injected tumor models (i.e. subcutaneous and orthotopic models). Using nanostring analysis and immunohistochemistry of prostates from 8-week-, 6-month-, and 12-month-old mice, we assessed immune cell infiltration levels, M2 characteristics of TAMs, and IL-4R alpha expression of TAMs. This data provides evidence for the M2-like characteristics of TAMs and IL-4R alpha as a viable TAM target. Subsequent experiments will include assessing IL-4R alpha expression on TAMs in human tumors using prostate cancer tissue microarrays. Moreover, we will continue to investigate the therapeutic potential of antagonizing IL-4R alpha through in vivo studies. In conclusion, these data implicate targeting IL-4R alpha as a promising therapeutic strategy for targeting TAMs in prostate cancer. Citation Format: Amber E. De Groot, Kayla Myers, Sarah R. Amend, Kenneth J. Pienta. Targeting IL-4R alpha on tumor-associated macrophages as a therapeutic strategy for prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2360.

The role of NLRP3 inflammasome in regulating the progression of prostate cancer

Chronic inflammation is a hallmark of cancers and plays a critical role in modulating tumor progression and metastasis. Inflammasomes are a group of cytosolic protein complexes, composed of an NOD‐like protein (NLR), the adaptor apoptosis‐associated speck‐like protein containing a caspase recruitment domain (ASC), and caspase‐1, which are responsible for the cleavage of pro‐IL‐1β and pro‐IL‐18 proteins into mature and biologically active IL‐1β and IL‐18, respectively. IL‐1β levels in tumor tissues were previously connected to poor prognosis for cancer patients. However, it remains unclear the function of inflammasomes in tumor growth and metastasis. The aim of this study is to examine whether the activation of NLRP3 inflammasome regulates the progression of prostate cancer. First, we screened the ability of NLRP3 inflammasome activation in prostate cells due to cancer heterogeneity. Prostate cell lines were primed with LPS, followed by treated with ATP or nigericin to induce NLRP3 inflammasome activation. Our results showed that the secretion of IL‐1β was significantly increased in PC3 (human prostate cancer cell line), BPH‐1 (human benign prostate hyperplasia epithelial cell line) and RWPE‐1 (human prostate epithelial cell line) cells. Second, we tested the effect of hypoxic condition in regulating the activation of NLRP3 inflammasome. Our results showed that hypoxia also induced the secretion of IL‐1β in PC3, BPH‐1 and RWPE‐1 cells. Third, we found that NLRP3 inflammasome activation involved in regulating tumor growth and metastasis. Our results indicated that the activation of NLRP3 inflammation plays an important role in modulating the progression of prostate cancer. Therefore, targeting NLRP3 inflammasome could be a strategy for prostate cancer therapy.Support or Funding InformationThis study was supported by the Ministry of Science and Technology, Taiwan, R.O.C. (Grant No. MOST 107‐2320‐B‐037‐019).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

1174 - Self-reported functional assessment by patients receiving different prostate cancer strategies: Five-year results from the VICAN large prospective cohort

1174 - Self-reported functional assessment by patients receiving different prostate cancer strategies: Five-year results from the VICAN large prospective cohort

Prostate cancer screening: controversies and suggested solutions

Prostate cancer is the most common cancer among men in industrialized countries. The annual incidence rate in Germany is about 60,000. Every year, 13,000 men die of this disease. Nevertheless, the 10-year survival rate is relatively favorable compared to other carcinomas.Prostate cancer screening is discussed controversially both nationally and internationally. This is due to the fact that the determination of the prostate-specific antigen (PSA) for tumor detection beginning in the 1980s led to over-diagnosis of clinically insignificant prostate cancer and consequently to over-therapy-usually by radical prostatectomy or radiotherapy.This review article will discuss the largest randomized controlled trials of PSA-based prostate cancer screening to date. It will highlight the advantages and disadvantages of this screening and give an outlook on the development of future strategies for prostate cancer screening.For PSA screening, the European Randomized Study for Screening of Prostate Cancer (ERSPC) study showed arelative reduction in prostate cancer-specific mortality of approximately 21% after amedian follow-up period of 13years. However, in absolute figures, relatively few men will benefit from population-based screening and the rate of over-diagnosed men remains high.The procedure in aSwedish long-term study, in which risk-adapted screening intervals were applied on the basis of the assessment of abaseline PSA level at ayoung age (40-50) showed promising results and may provide asolution to this dilemma. This strategy is the basis for the currently largest study on risk-adapted prostate cancer screening ( www.PROBASE.de ), which evaluates this concept for the first time with arandomized design.

Abstract 4046: The different immune evasion mechanisms in human prostate cancer

Abstract Cancer development is associated with a number of genetic and epigenetic alternations. Normally, these alterations are detected by the immune system in a process called immune surveillance, where cancer cell killing is mediated by cytotoxic T lymphocytes (CTL) and natural killer cells (NK cells). Yet, tumor progression and development indicate that cancer cells have acquired mechanisms to avoid immune destruction. Various immune evasion mechanisms have been reported before such as impaired antigen presentation and activation of CTL and NK cells, immunosuppression, and induction of tolerance. Although current treatment methods are shifting towards more targeted strategies in prostate cancer, such as immunotherapy, a better understanding of the cancer-immune interactions and immune evasion mechanisms is yet to be established. More immunotherapies are being developed and approved by the FDA for treating cancer. In prostate cancer, Sipuleucel-T, an autologous cellular immunotherapy, was approved by FDA for the treatment of asymptomatic or minimally symptomatic metastatic castrate resistant (hormone refractory) prostate cancer. Intensive investigation on other immunotherapies is ongoing in prostate cancer. These include blockade of negative checkpoint regulators (PD-1, CTLA4) and Ig superfamily member V-domain Ig-containing suppressor of T-cell activation (VISTA), chimeric antigen receptor-modified T (CAR-T) cells against prostate lineage-unique proteins (PLUPs), and monoclonal antibodies targeting immunoinhibitory molecules. However, the optimal choice of treatment for a prostate cancer patient needs to target their specific mechanisms of immune evasion, which are poorly studied. In this study, we will use The Cancer Genome Atlas RNA-seq data to check for immune evasion gene expression in prostate cancer patients to identify at the different mechanisms by which cancer avoids immune destruction. We will use a sequential biclustering algorithm developed by our group, to group prostate cancer patients based on their similarities in immune evasion gene expression. A similar unpublished work was done by our group on breast cancer where we identified 7 different groups of patients, each with different mechanisms or combination of evasion mechanism. We also showed that triple negative breast cancer can be immunogenic and non-immunogenic. This group-based identification of evasion mechanisms will not only provide a better understanding of the different immune evasion mechanisms in prostate cancer, but will also shed light on potential combinations of mechanism. This in turn, will help guide the choice of single and combined immunotherapeutic approches. Citation Format: Mayassa J. Bou-Dargham, Yuhang Liu, Qing-Xiang Amy Sang, Jinfeng Zhang. The different immune evasion mechanisms in human prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4046.

Self-reported functional assessment by patients receiving different prostate cancer strategies: Five-year results from the VICAN large prospective cohort.

10077Background: Several treatment options are available for prostate cancer (PC) with different functional side effects. The aim of our study was to assess the long-term consequences of the therap...

Contrast enhanced ultrasound (CEUS) with MRI image fusion for monitoring focal therapy of prostate cancer with high intensity focused ultrasound (HIFU)1.

Reduced acceptance of radical prostatectomy in patients with low risk or intermediate risk prostate cancer has significantly changed treatment strategies in prostate cancer (PCa) during the last years. Focal therapy of the prostate with high intensity focused ultrasound (HIFU) is an organ-preserving treatment for prostate cancer with less impairment of health-related quality of life. Follow-up after HIFU therapy by imaging modalities remains a major problem as eg. MRI performs poorly. Contrast enhanced ultrasound (CEUS) allows to monitor the vascular architecture of organs non-invasively. However, only limited data are available using CEUS to define successful and complete HIFU treatment of the prostate. In this study, we aimed to evaluate short-term image findings using CEUS and image fusion before and after HIFU treatment. Prospective single arm study in patients with uni- or bilateral, low or intermediate risk prostate cancer or recurrent cancer after radiotherapy treated with HIFU at our institution between October 2016 and November 2017. HIFU hemiablation or whole gland treatment was performed using the Focal One® device. PCa was diagnosed either by multiparametric magnetic resonance imaging (mpMRI) followed by MRI fusion based targeted biopsy combined with 12 core transrectal ultrasound (TRUS) guided biopsy or 12 core random biopsy only. Monitoring of the target region before, immediately and 24 hours after the ablation was done by CEUS in combination with image fusion using an axial T2-weighted MRI sequence. 6 consecutive patients with Gleason score (GS) 6, 5 patients with GS 7a prostate cancer and one patient with biochemical recurrence after radiotherapy were included in the study. Three patients underwent whole gland treatment due to histological proven bilateral PCa or recurrent PCa after radiotherapy. Hemiablation was performed in 9 patients with unilateral tumor and no PIRADS 4 or 5 lesion in the contralateral lobe. Median patient age was 69.8 years and median PSA (prostate-specific antigen) level was 8.4 ng/ml. CEUS showed markedly reduced microbubbles in the ablated area, the prostate capsule still showed signs of perfusion. The study is limited by the short follow up and small number of patients. CEUS examination showed a reduction of microcirculation in the treated area immediately after the treatment and 24 hours later. The combination of CEUS and image fusion seems to be helpful for detecting the PCa target lesion and monitor the success of HIFU ablation treatment. Evidence for image findings after HIFU-therapy are rare. Further studies on this topic are needed.

Glypican-1 as a novel immunotherapeutic target in prostate cancer

174Background: New effective therapies for men with prostate cancer are desperately needed. Recently, cancer immunotherapy has emerged as an important new treatment strategy for prostate cancer and for castrate resistant prostate cancer (CRPC). Multiple studies have identified the heparan sulfate proteoglycan-1 Glypican 1 (GPC-1) as being overexpressed in different cancers, and also as being a possible marker of poor prognosis in several solid tumor cancers. GPC-1 has been recently identified as a potential marker for prostate cancer. The MIL-38 monoclonal antibody detects GPC-1 and an IgG1 chimeric version of this antibody has been developed for preclinical studies. Here we sought to examine MIL-38 binding to a panel of prostate cancer cell lines and examine its feasibility as a novel immunotherapeutic agent targeting GPC-1 in prostate cancer Methods: Expression of GPC-1 in CRPC cell lines was examined by Flow cytometry and Western Blotting using MIL-38 as the detector antibody. The competency of GPC-1 a...

Abstract 189: Development of peptidomimetic inhibitors of the ERG gene fusion product in prostate cancer

Abstract Transcription factors play a key role in the development of diverse cancers, and therapeutically targeting them has remained a challenge. In prostate cancer, the gene encoding the transcription factor ERG is recurrently rearranged and plays a critical role in prostate oncogenesis. Here, we identified a series of peptides that interact specifically with the DNA binding domain of ERG. ERG inhibitory peptides and derived peptidomimetics (EIPs) bound with high affinity and specificity leading to proteolytic degradation of ERG protein. The EIPs attenuated ERG-mediated transcription, chromatin recruitment, protein-protein interactions, cell invasion, and tumor growth. Thus, peptidomimetic targeting of transcription factor fusion products may provide a promising therapeutic strategy for prostate cancer as well as other cancers. Citation Format: Xiaoju Wang. Development of peptidomimetic inhibitors of the ERG gene fusion product in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 189. doi:10.1158/1538-7445.AM2017-189

Resveratrol and pterostilbene as a microRNA-mediated chemopreventive and therapeutic strategy in prostate cancer.

Growing evidence indicates that deregulation of the epigenetic machinery comprising the microRNA (miRNA) network is a critical factor in the progression of various diseases, including cancer. Concurrently, dietary phytochemicals are being intensively studied for their miRNA-mediated health-beneficial properties, such as anti-inflammatory, cardioprotective, antioxidative, and anticancer properties. Available experimental data have suggested that dietary polyphenols may be effective miRNA-modulating chemopreventive and therapeutic agents. Moreover, noninvasive detection of changes in miRNA expression in liquid biopsies opens enormous possibilities for their clinical utilization as novel prognostic and predictive biomarkers. In our published studies, we identified resveratrol-regulated miRNA profiles in prostate cancer. Resveratrol downregulated the phosphatase and tensin homolog (PTEN)-targeting members of the oncogenic miR-17 family of miRNAs, which are overexpressed in prostate cancer. We have functionally validated the miRNA-mediated ability of resveratrol and its potent analog pterostilbene to rescue the tumor suppressor activity of PTEN in vitro and in vivo. Taken together, our findings implicate the use of resveratrol and its analogs as an attractive miRNA-mediated chemopreventive and therapeutic strategy in prostate cancer and the use of circulating miRNAs as potential predictive biomarkers for clinical development.

Identification of Filamin-A and -B as potential biomarkers for prostate cancer.

Aim:A novel strategy for prostate cancer (PrCa) biomarker discovery is described.Materials & methods:In vitro perturbation biology, proteomics and Bayesian causal analysis identified biomarkers that were validated in in vitro models and clinical specimens.Results:Filamin-B (FLNB) and Keratin-19 were identified as biomarkers. Filamin-A (FLNA) was found to be causally linked to FLNB. Characterization of the biomarkers in a panel of cells revealed differential mRNA expression and regulation. Moreover, FLNA and FLNB were detected in the conditioned media of cells. Last, in patients without PrCa, FLNA and FLNB blood levels were positively correlated, while in patients with adenocarcinoma the relationship is dysregulated.Conclusion:These data support the strategy and the potential use of the biomarkers for PrCa.