Prostate Tumor Cells Research Articles

Abstract LB-023: Describing prostate cancer heterogeneity through single cell analysis with mass cytometry

Abstract Background Single-cell analysis has emerged as a crucial approach to detect variations in genetic and proteomic expression. Prostate cancer is characterized by multiple genomic alterations leading to the complex nature of the disease. The heterogeneity at the proteomic level is not yet well characterized, yet intra-tumor heterogeneity can impair correct diagnosis and treatment, by driving therapy resistance. Meanwhile inter-tumor heterogeneity can strongly impact personalization of treatments highlighting the importance of characterizing both intra- and inter-tumor heterogeneity. Using single-cell mass cytometry data, we identify the proteomic profiles of the different cellular subpopulations found in prostate cancer that are common across a cohort of 50 patients while also describing the variations across patients, thus thoroughly characterizing prostate tumor heterogeneity. Methods & Results Mass cytometry experiments allow quantification of dozens of proteins simultaneously at the single-cell level, for thousands of cells. The high dimensionality of this data represents a challenge for data visualization and clustering, which require computational approaches for interpretation of the results. We developed a new computational method to address this task and analyzed tissue sections from surgically removed prostates from 50 patients using mass cytometry with a comprehensive set of 40 antibodies to jointly identify surface markers, enzymes, transcription factors and functional readouts. Conclusions Here, we present for the first time an analysis of prostate tumor cell heterogeneity by mass cytometry coupled to a newly developed computational method that improves visualization and clustering of such high-dimensional data. This study was conducted by analyzing prostate cancer samples from fifty patients at the single-cell level using mass cytometry to estimate the abundance of forty different proteins simultaneously for each cell. Our results show that immune, stromal and epithelial cells can be comprehensively distinguished across all patients. A closer look at the epithelial compartment reveals multiple subpopulations which we describe in terms of their protein expression patterns to characterize the intra- and inter-tumor heterogeneity in prostate cancer. This work demonstrates how single cell phenotypic profiles of prostate tumor cells, taken from surgically removed prostates, can be used to quantify the varying heterogeneity during tumor progression. Citation Format: Laura De Vargas Roditi, Andrea Jacobs, Christian Fankhauser, Cedric Poyet, Peter Wild, Bernd Bodenmiller. Describing prostate cancer heterogeneity through single cell analysis with mass cytometry [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 LB-023.

PO-075 Methanol fraction of calliandra portoricensis induces apoptosis and growth arrest in prostatic tumour cell lines

IntroductionApoptosis is down regulated in most forms of cancer. Mitochondria are central to the apoptotic process and are targeted in cancer therapy by novel drug candidates. Calliandra portoricensis (CP) is used in the management of prostate enlargement in folk medicine. This study was designed to investigate the effects of CP on mitochondrial-mediated apoptosis and cell proliferation using prostate cancer cells.Material and methodsProstate cancer cells were treated with methanol fraction of CP (MFCP), cell cycle analysis was evaluated by flow cytometry and levels of pro-apoptotic Bax, anti-apoptotic Bcl-2, Cytochrome C Release and activation of caspases 3and 9 were determined using ELISA kits.Results and discussionsThe MFCP inhibited (p<0.05) proliferation of prostatic cancer cells. The growth inhibition by MFCP (10 µg/mL) correlated with a 3-fold decreased expression of Bcl-2 and a 4-fold increase in Bax levels in LNCaP cells. The MFCP (10 µg/mL) activated C3 and C9 at by 4.2 and 5.1 folds over control, respectively which prompted cancer cells to arrest at S phase. The LC-MS analysis revealed the presence of polyphenols in MFCP.ConclusionTaken together, MFCP- induced cell death is mediated by alteration of mitochondrial integrity and cell cycle arrest. Hence, MFCP may be effective for cancer pharmacotherapy.

Abstract 2432: The genomic consequences of tumor hypoxia in human cancers

Abstract Introduction: Localized prostate cancers are classified into risk-groups using clinical measurements like grade and stage to inform treatment decisions. However, these groupings are imprecise: ~30% of intermediate-risk patients suffer relapse of their disease despite precision image-guided radiotherapy or radical prostatectomy. One reason for this variability in response to treatment is the underlying cellular and molecular heterogeneity of tumors. Prostate tumor cells exist within a microenvironment characterized by gradients of oxygen levels and prostate tumors with low levels of oxygen (hypoxia) have poor clinical outcomes. Methods and Results: To understand the correlates of hypoxia in cancer we conducted a pan-cancer analysis of copy number alterations (CNAs) and single nucleotide variants (SNVs) across 19 cancer types. We measured hypoxia using multiple mRNA-based signatures and discovered numerous CNAs and SNVs enriched or depleted in hypoxic tumors, highlighting the role of hypoxia in shaping the genomic landscape of multiple tumor types. Next, we examined 548 patients with localized prostate cancer and statistically assessed the association of hypoxia with CNAs, SNVs, genomic rearrangements, focal genomic events (i.e. kataegis, chromothripsis), telomere length, clinical indices (i.e. grade, stage) and subclonal architecture. Tumor hypoxia is associated with specific CNAs and SNVs in prostate cancer driver genes. To translate these findings into a biomarker for prostate cancer precision medicine, we integrated tumor microenvironmental data with genomic and pathological information to stratify patients into distinct prognostic groups. Impact: These data suggest that the aggressiveness of cancers is driven by the interplay of the tumor microenvironment and its genomic mutational profile. Citation Format: Vinayak Bhandari, Shadrielle M. Espiritu, Lydia Y. Liu, Emilie Lalonde, Takafumi N. Yamaguchi, Lawrence E. Heisler, Julie Livingstone, Vincent Huang, Yu-Jia Shiah, Veronica Y. Sabelnykova, Fouad Yousif, Melvin L. Chua, Michael Fraser, Theodorus van der Kwast, Paul C. Boutros, Robert G. Bristow. The genomic consequences of tumor hypoxia in human cancers [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 2432.

Abstract 4486: Reexpression of LSAMP, a gene frequently deleted in African American prostate cancers, alters adhesive qualities of prostate tumor cells and inhibits Akt, ERK1/2, and β-Catenin signaling axis

Abstract INTRODUCTION: Although African American (AA) men have the highest prostate cancer (CaP) incidence and mortality rates in the US, most studies of CaP genome have been performed using tumor specimens from Caucasian Americans (CA). To address the underrepresentation of AA CaP in these studies, we performed whole genome sequencing, IHC and FISH validation on tissue microarrays, and analysis of TCGA data, on a total of 438 CaPs. We noted less frequent alterations of two common CaP driver genes, PTEN and ERG, in CaP genomes of AA compared to CA men, confirming earlier observations by others and us. We reported a higher frequency of a genomic deletion of the Limbic System Associated Membrane Protein (LSAMP) gene, located on 3q13.31 locus in AA CaP, which was also associated with rapid biochemical recurrence. A recent study of CaP genome in a Chinese cohort detected LSAMP alterations at a frequency similar to that in our AA cases. LSAMP loss in other cancers have been associated with aggressive disease. We hypothesize that the loss of LSAMP contributes to CaP progression. Here, we report further biological evaluations of LSAMP modulation in CaP cells. METHODS: The copy number and expression of LSAMP in CaP cell lines were assessed. We established stable doxycycline inducible LSAMP expression in LNCaP and in MDA PCa 2b cells (AA patient derived cell line with monoallelic LSAMP deletion), and constitutive expression in DU145 cells. We assessed the effect of LSAMP expression on cell-cell adhesion by monitoring the binding of LSAMP expressing and control DU145 cells to mouse fibroblast (NIH-3T3), normal human prostate stroma (WPMY-1), human endothelial (HUVEC), and human bone marrow stroma (HS-5) cells. We analyzed LSAMP modulated signaling pathways in the inducible and constitutively LSAMP expressing cell lines by immunoblot and immunofluorescence assays. RESULTS: Overexpression of LSAMP resulted in attenuated cell proliferation and increased adhesion of cells to extracellular matrix proteins. LSAMP expression in DU145 cells increased their adhesion to fibroblast and prostate stroma cell lines, and concomitantly decreased their adhesion to endothelial, and bone marrow stroma cells. LSAMP expression resulted in decreased expression of FGFR2, FGFR4, and EphA3 receptor tyrosine kinases, and decreased phosphorylation of their downstream targets in Akt and ERK1/2 signaling pathways, leading to the inactivation of β-catenin. LSAMP expression also alters the levels of some Integrins. CONCLUSION: Cell biologic features of LSAMP reported here, along with observations of genomic inactivations of LSAMP in CaP support its role in CaP progression through altered cell adhesion. These data provide the first insight into LSAMP function in CaP, corroborating with studies that suggest bona fide tumor suppressor function for LSAMP in cancers. Citation Format: Kevin Babcock, Inger L. Rosner, Shiv Srivastava, Albert Dobi, Shyh-Han Tan. Reexpression of LSAMP, a gene frequently deleted in African American prostate cancers, alters adhesive qualities of prostate tumor cells and inhibits Akt, ERK1/2, and β-Catenin signaling axis [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 4486.

Abstract 4380: Role of FAM3B/PANDER in inhibition of cell death and tumor growth in breast and prostate cancer

Abstract FAM3B/PANDER is a novel cytokine-like protein that induces apoptosis in beta-cells and regulates the effects of insulin in peripheral tissues. Since previous data revealed that FAM3B can be expressed by prostate and breast tumors, we evaluated the role of this cytokine in prostate and breast tumor progression. FAM3B expression was compared by quantitative PCR in LnCAP, PC-3 and DU145 prostate tumor cell lines and MCF-7 and MDA-MB- 231 breast tumor cell lines. After treatment with either recombinant FAM3B protein or secreted FAM3B obtained from conditioned media (CM) derived from FAM3B-overexpressing 293T cells, the cell death and viability of DU145 and MDA-MB- 231 cell lines were evaluated. DU145 and MDA-MB- 231 cells overexpressing FAM3B protein were produced by lentiviral-mediated transduction of full-length FAM3B cDNA. Cell viability and apoptosis were analyzed in DU145-FAM3B and MDA-231-FAM3B cells after treatment with cell death inducers. Anchorage-independent growth and scratch wound assays were used to evaluate in vitro tumorigenicity and cell migration, respectively. In vivo tumorigenicity and invasiveness were evaluated by tumor xenograft growth in nude mice. We observed that FAM3B was highly expressed by hormone responsive cells (LnCAP and MCF-7) and low expressed in unresponsive hormone cells (PC-3, DU145 and MDA-MB- 231). Cell viability and survival of DU145 and MDA-MB- 231 cells increased after exogenous treatment with recombinant FAM3B protein or CM containing FAM3B-secreted protein. Overexpression of FAM3B in DU145 and MDA-MB- 231 cells promoted an inhibition of apoptosis triggered by TNF-alpha and staurosporine. Cell death inhibition was accompanied by increased gene expression of the anti-apoptotic Bcl-2 and Bcl-xL genes, and by slight decrease in expression of pro-apoptotic gene Bax and with a decrease of caspases proteolytic activities. When compared to control, cells overexpressing FAM3B displayed a decreased anchorage independent growth and increased motility in vitro, as well as an increased tumor growth in xenografted nude mice. In agreement Immunohistochemistry analysis from tumor xenografts revealed similar anti-apoptotic phenotype in FAM3B overexpression, with an increase of Bcl-2. The results showed that FAM3B was capable to activates pro-survival mechanisms with an increasing of tumor growth by, activation of Bcl-2 and Bcl-xl pathways, suggesting the role of this cytokine in breast and in prostate tumors progression. Citation Format: Izabela D. Caldeira. Role of FAM3B/PANDER in inhibition of cell death and tumor growth in breast and 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 4380.

IL-23 secreted by myeloid cells drives castration-resistant prostate cancer.

Patients with prostate cancer frequently show resistance to androgen-deprivation therapy, a condition known as castration-resistant prostate cancer (CRPC). Acquiring a better understanding of the mechanisms that control the development of CRPC remains an unmet clinical need. The well-established dependency of cancer cells on the tumour microenvironment indicates that the microenvironment might control the emergence of CRPC. Here we identify IL-23 produced by myeloid-derived suppressor cells (MDSCs) as a driver of CRPC in mice and patients with CRPC. Mechanistically, IL-23 secreted by MDSCs can activate the androgen receptor pathway in prostate tumour cells, promoting cell survival and proliferation in androgen-deprived conditions. Intra-tumour MDSC infiltration and IL-23 concentration are increased in blood and tumour samples from patients with CRPC. Antibody-mediated inactivation of IL-23 restored sensitivity to androgen-deprivation therapy in mice. Taken together, these results reveal that MDSCs promote CRPC by acting in a non-cell autonomous manner. Treatments that block IL-23 can oppose MDSC-mediated resistance to castration in prostate cancer and synergize with standard therapies.

Dendritic cell trafficking in tumor-bearing mice.

Prostate cancer is one of the leading causes of cancer deaths, with no curative treatments once it spreads. Alternative therapies, including immunotherapy, have shown limited efficacy. Dendritic cells (DC) have been widely used in the treatment of various malignancies. DC capture antigens and move to the lymphoid organs where they prime naive T cells. Interaction between DC and T cells are most active in lymph nodes and suppression of DC trafficking to lymph nodes impairs the immune response. In this work, we aimed to study trafficking of DC in vivo via various routes of delivery, to optimize the effectiveness of DC-based therapy. A DC labeling system was developed using 1,1'-dioctadecyltetramethyl indotricarbocyanine Iodine for in vivo fluorescent imaging. DC harvested from C57B/6 mice were matured, labeled, and injected intravenously, subcutaneously, or intratumorally, with or without antigen loading with whole tumor lysate, into C57B/6 mice inoculated with RM-1 murine prostate tumor cells. Signal intensity was measured in vivo and ex vivo. Signal intensity at the tumor site increased over time, suggesting trafficking of DC to the tumor with all modes of injection. Subcutaneous injection showed preferential trafficking to lymph nodes and tumor. Intravenous injection showed trafficking to lungs, intestines, and spleen. Subcutaneous injection of DC pulsed with whole tumor lysate resulted in the highest increase in signal intensity at the tumor site and lymph nodes, suggesting subcutaneous injection of primed DC leads to highest preferential trafficking of DC to the immunocompetent organs.

Spatial Intratumor Genomic Heterogeneity within Localized Prostate Cancer Revealed by Single-nucleus Sequencing

BackgroundProstate adenocarcinoma (PCa) is a complex genetic disease, and the implementation of personalized treatment in PCa faces challenges due to significant inter- and intrapatient tumor heterogeneities. ObjectiveTo systematically explore the genomic complexity of tumor cells with different Gleason scores (GSs) in PCa. Design, setting, and participantsWe performed single-cell whole genome sequencing of 17 tumor cells from localized lesions with distinct GS and matched four normal samples from two prostatectomy patients. Outcome measurements and statistical analysisAll classes of genomic alterations were identified, including substitutions, insertions/deletions, copy number alterations, and rearrangements. Results and limitationsSignificant spatial, intra- and intertumoral heterogeneities were observed at the cellular level. In the patient 1, all cells shared the same TP53 driver mutation, implying a monoclonal origin of PCa. In the patient 2, only a subpopulation of cells contained the TP53 driver mutation, whereas other cells carried different driver mutations, indicating a typical polyclonal model with separate clonal cell expansions. The tumor cells from different sides of prostate owned various mutation patterns. Considerable neoantigens were predicted among different cells, implying unknown immune editing components helping prostate tumor cells escaping from immune surveillance. ConclusionsThere is a significant spatial genomic heterogeneity even in the same PCa patient. Our study also provides the first genome-wide evidence at single-cell level, supporting that the origin of PCa could be either polyclonal or monoclonal, which has implications for treatment decisions for prostate cancer. Patient summaryWe reported the first single-cell whole genomic data of prostate adenocarcinoma (PCa) from different Gleason scores. Identification of these genetic alterations may help understand PCa tumor progression and clonal evolution.

Microenvironment proteinases, proteinase-activated receptor regulation, cancer and inflammation.

We propose that in the microenvironment of inflammatory tissues, including tumours, extracellular proteinases can modulate cell signalling in part by regulating proteinase-activated receptors (PARs). We have been exploring this mechanism in a variety of inflammation and tumour-related settings that include tumour-derived cultured cells from prostate and bladder cancer, as well as immune inflammatory cells that are involved in the pathology of inflammatory diseases including multiple sclerosis. Our work showed that proteinase signalling via the PARs affects prostate and bladder cancer-derived tumour cell behaviour and can regulate calcium signalling in human T-cell and macrophage-related inflammatory cells as well as in murine splenocytes. Further, we found that the tumour-derived prostate cancer cells and immune-related cells (Jurkat, THP1, mouse splenocytes) can produce PAR-regulating proteinases (including kallikreins: kallikrein-related peptidases), that can control tissue function by both a paracrine and autocrine mechanism. We suggest that this PAR-driven signalling process involving secreted microenvironment proteinases can play a key role in cancer and inflammatory diseases including multiple sclerosis.

The presence of secondary circulating prostate tumour cells determines the risk of biochemical relapse for patients with low- and intermediate-risk prostate cancer who are treated only with external radiotherapy.

IntroductionThe classification of patients with prostate cancer is used to determine treatments based on risk factors. The presence of secondary circulating prostate tumour cells (CPCs) detected in peripheral blood after a curative treatment has been associated with a worse prognosis. We present a prospective study of CPC detection post radiotherapy and the oncological results.Patients and methodsAll of the patients classified as low and intermediate risk that were treated with radiotherapy were included. Three months after finishing treatment, an 8-ml blood sample was taken to detect CPCs. Mononuclear cells were obtained using gel centrifugation, and CPCs were identified using immunocytochemistry with anti-prostate-specific antigen. Patients were classified as low-risk CPC positive or negative and intermediate-risk CPC positive or negative. The biochemical relapse-free survival analysis was determined based on a follow-up of up to 15 years using the Kaplan–Meier and Cox regression models. Biochemical failure was defined according to the Pheonix II criteria.ResultsOf 241 patients, 181 (75.1%) were classified as low risk and 60 (24.9%) as intermediate risk. Biochemical failure was observed in 27.1% (49/181) of the low-risk prostate cancer participants and in 53.3% (32/60) of intermediate-risk participants after 15 years of follow-up. 20.4% (37/181) of the low-risk cancer participants had detectable CPCs in comparison with 43.3% (26/60) of the intermediate-risk cancer participants (p < 0.001 overall risk 2.98, confidence interval (CI) 95% 1.59–5.56; relative risk 2.12, CI 95% 1.41–3.19). Positive CPC patients had a worse prognosis, and a shorter time period until biochemical relapse, regardless of risk group. The biochemical relapse-free survival curves show that intermediate-risk participants who were CPC negative had a higher survival rate and slower disease progression than those participants who were low risk but CPC positive.ConclusionsCPC detection is a risk factor for biochemical relapse and could be useful in identifying patients that will need additional treatment.

Zika Virus Selectively Kills Aggressive Human Embryonal CNS Tumor Cells In Vitro and In Vivo.

Zika virus (ZIKV) is largely known for causing brain abnormalities due to its ability to infect neural progenitor stem cells during early development. Here, we show that ZIKV is also capable of infecting and destroying stem-like cancer cells from aggressive human embryonal tumors of the central nervous system (CNS). When evaluating the oncolytic properties of Brazilian Zika virus strain (ZIKVBR) against human breast, prostate, colorectal, and embryonal CNS tumor cell lines, we verified a selective infection of CNS tumor cells followed by massive tumor cell death. ZIKVBR was more efficient in destroying embryonal CNS tumorspheres than normal stem cell neurospheres. A single intracerebroventricular injection of ZIKVBR in BALB/c nude mice bearing orthotopic human embryonal CNS tumor xenografts resulted in a significantly longer survival, decreased tumor burden, fewer metastasis, and complete remission in some animals. Tumor cells closely resembling neural stem cells at the molecular level with activated Wnt signaling were more susceptible to the oncolytic effects of ZIKVBR Furthermore, modulation of Wnt signaling pathway significantly affected ZIKVBR-induced tumor cell death and viral shedding. Altogether, these preclinical findings indicate that ZIKVBR could be an efficient agent to treat aggressive forms of embryonal CNS tumors and could provide mechanistic insights regarding its oncolytic effects.Significance: Brazilian Zika virus strain kills aggressive metastatic forms of human CNS tumors and could be a potential oncolytic agent for cancer therapy. Cancer Res; 78(12); 3363-74. ©2018 AACR.

Mechanisms and Approaches for Overcoming Enzalutamide Resistance in Prostate Cancer.

Enzalutamide, a second-generation small-molecule inhibitor of the androgen receptor (AR), has been approved for patients who failed with androgen deprivation therapy and have developed castration-resistant prostate cancer. More than 80% of these patients develop bone metastases. The binding of enzalutamide to the AR prevents the nuclear translocation of the receptor, thus inactivating androgen signaling. However, prostate cancer cells eventually develop resistance to enzalutamide treatment. Studies have found resistance both in patients and in laboratory models. The mechanisms of and approaches to overcoming such resistance are significant issues that need to be addressed. In this review, we focus on the major mechanisms of acquired enzalutamide resistance, including genetic mutations and splice variants of the AR, signaling pathways that bypass androgen signaling, intratumoral androgen biosynthesis by prostate tumor cells, lineage plasticity, and contributions from the tumor microenvironment. Approaches for overcoming these mechanisms to enzalutamide resistance along with the associated problems and solutions are discussed. Emerging questions, concerns, and new opportunities in studying enzalutamide resistance will be addressed as well.

Targeting prostate cancer: Prostate-specific membrane antigen based diagnosis and therapy.

The high incidence rates of prostate cancer (PCa) raise demand for improved therapeutic strategies. Prostate tumors specifically express the prostate-specific membrane antigen (PSMA), a membrane-bound protease. As PSMA is highly overexpressed on malignant prostate tumor cells and as its expression rate correlates with the aggressiveness of the disease, this tumor-associated biomarker provides the possibility to develop new strategies for diagnostics and therapy of PCa. Major advances have been made in PSMA targeting, ranging from immunotherapeutic approaches to therapeutic small molecules. This review elaborates the diversity of PSMA targeting agents while focusing on the radioactively labeled tracers for diagnosis and endoradiotherapy. A variety of radionuclides have been shown to either enable precise diagnosis or efficiently treat the tumor with minimal effects to nontargeted organs. Most small molecules with affinity for PSMA are based on either a phosphonate or a urea-based binding motif. Based on these pharmacophores, major effort has been made to identify modifications to achieve ideal pharmacokinetics while retaining the specific targeting of the PSMA binding pocket. Several tracers have now shown excellent clinical usability in particular for molecular imaging and therapy as proven by the efficiency of theranostic approaches in current studies. The archetypal expression profile of PSMA may be exploited for the treatment with alpha emitters to break radioresistance and thus to bring the power of systemic therapy to higher levels.

Prostate tumor cell exosomes containing hyaluronidase Hyal1 stimulate prostate stromal cell motility by engagement of FAK-mediated integrin signaling

The hyaluronidase Hyal1 is clinically and functionally implicated in prostate cancer progression and metastasis. Elevated Hyal1 accelerates vesicular trafficking in prostate tumor cells, thereby enhancing their metastatic potential in an autocrine manner through increased motility and proliferation. In this report, we found Hyal1 protein is a component of exosomes produced by prostate tumor cell lines overexpressing Hyal1. We investigated the role of exosomally shed Hyal1 in modulating tumor cell autonomous functions and in modifying the behavior of prostate stromal cells. Catalytic activity of Hyal1 was necessary for enrichment of Hyal1 in the exosome fraction, which was associated with increased presence of LC3BII, an autophagic marker, in the exosomes. Hyal1-positive exosome contents were internalized from the culture medium by WPMY-1 prostate stromal fibroblasts. Treatment of prostate stromal cells with tumor exosomes did not affect proliferation, but robustly stimulated their migration in a manner dependent on Hyal1 catalytic activity. Increased motility of exosome-treated stromal cells was accompanied by enhanced adhesion to a type IV collagen matrix, as well as increased FAK phosphorylation and integrin engagement through dynamic membrane residence of β1 integrins. The presence of Hyal1 in tumor-derived exosomes and its ability to impact the behavior of stromal cells suggests cell-cell communication via exosomes is a novel mechanism by which elevated Hyal1 promotes prostate cancer progression.

Cabazitaxel regimens inhibit the growth of prostate cancer cells and enhances the anti‐tumor properties of PEDF with various efficacy and toxicity

Taxanes chemotherapies represent the major therapeutic alternative for symptomatic mCRPC. While docetaxel is the most commonly prescribed Taxane for mCRPC; cabazitaxel has been approved for patients unresponsive to docetaxel. Still mCRPC remains incurable and patients often experience severe side effects. Recently, the FIRSTANA trial first demonstrated the absence of superiority in overall survival between cabazitaxel and docetaxel in mCRPC patients. Inversely, different toxicity were reported suggesting that cabazitaxel may provide a first line treatment option for some patients urging for a deeper characterization of cabazitaxel mechanisms of action as well as a re-evaluation of cabazitaxel conventional dose and schedule. In this study, our goal was therefore to evaluate the anti-tumor efficacy of various cabazitaxel regimens delivered as monotherapy or in combination with PEDF, a known anti-angiogenic and anti-neoplastic agent. CRPC cells undergoing Taxane treatment were evaluated for cell proliferation, migration and death, and apoptosis using crystal violet staining, chemotaxis, cell cycle, and TUNEL assays. In vitro data were corroborated in CL1 CRPC xenografts where mice received intermittent or metronomic low-doses cabazitaxel ± PEDF. We found that cabazitaxel inhibits the proliferation of CRPC cells with a higher efficacy than docetaxel in vitro. As expected, high-doses of Taxanes blocked the cells in mitosis. Surprisingly, low-doses of cabazitaxel induced more cell death than docetaxel mainly through apoptosis. In vivo, intermittent cabazitaxel lead to disease stabilization when combined with PEDF. Unexpectedly, low-doses of cabazitaxel delayed tumor growth with severe toxicity for some of the doses tested. Other results showed that PEDF and low-doses of cabazitaxel combination inhibited the migration of tumor cell and increased the tumoricidal activity of macrophages toward prostate tumor cells. Our findings highlight the great promise of cabazitaxel drug and predict a possible move of cabazitaxel forward within the therapeutic sequence of prostate cancer.

Nanoparticle-based targeted cancer strategies for non-invasive prostate cancer intervention.

Prostate cancer is screened by testing circulating levels of the prostate-specific antigen (PSA) biomarker, monitoring changes over time, or a digital rectal exam. Abnormal results often lead to prostate biopsy. Prostate cancer positive patients are stratified into very low-risk, low-risk, intermediate-risk, and high-risk, based on clinical classification parameters, to assess therapy options. However, there remains a gap in our knowledge and a compelling need for improved risk stratification to inform clinical decisions and reduce both over-diagnosis and over-treatment. Further, current strategies for clinical intervention do not distinguish clinically aggressive prostate cancer from indolent disease. This mini-review takes advantage of a large number of functionally characterized microRNAs (miRNA), epigenetic regulators of prostate cancer, that define prostate cancer cell activity, tumor stage, and circulate as biomarkers to monitor disease progression. Nanoparticles provide an effective platform for targeted delivery of miRNA inhibitors or mimics specifically to prostate tumor cells to inhibit cancer progression. Several prostate-specific transmembrane proteins expressed at elevated levels in prostate tumors are under investigation for targeting therapeutic agents to prostate cancer cells. Given that prostate cancer progresses slowly, circulating miRNAs can be monitored to identify tumor progression in indolent disease, allowing identification of miRNAs for nanoparticle intervention before the crucial point of transition to aggressive disease. Here, we describe clinically significant and non-invasive intervention nanoparticle strategies being used in clinical trials for drug and nucleic acid delivery. The advantages of mesoporous silica-based nanoparticles and a number of candidate miRNAs for inhibition of prostate cancer are discussed.

A ribonucleoprotein octamer for targeted siRNA delivery.

Hurdles in cell-specific delivery of small interfering RNA (siRNA) in vivo hinder the clinical translation of RNA interference (RNAi). A fundamental problem concerns conflicting requirements for the design of the delivery vehicles: cationic materials facilitate cargo condensation and endosomolysis, yet hinder in vivo targeting and colloidal stability. Here, we describe a self-assembled, compact (~30 nm) and biocompatible ribonucleoprotein-octamer nanoparticle that achieves endosomal destabilization and targeted delivery. The protein octamer consists of a poly(ethylene glycol) scaffold, a sterically masked endosomolytic peptide, and a double-stranded RNA-binding domain, provides a discrete number of siRNA loading sites and a high siRNA payload (> 30 wt%), and offers flexibility in both siRNA and targeting-ligand selection. We show that a ribonucleoprotein octamer against the polo-like kinase 1 (Plk1) gene and bearing a ligand that binds to prostate specific membrane antigen (PSMA) leads to efficient gene silencing in prostate tumour cells in vitro and when intravenously injected in mouse models of prostate cancer. The octamer’s versatile nanocarrier design should offer opportunities for the clinical translation of therapies based on intracellularly acting biologics.

MP64-11 CHEMOPREVENTIVE AND CHEMOTHERAPEUTIC POTENTIALS OF LUTEOLIN VIA REGULATION OF OXIDATIVE STRESS IN CASTRATION-RESISTANT PROSTATE CANCER

You have accessJournal of UrologyProstate Cancer: Basic Research & Pathophysiology II1 Apr 2018MP64-11 CHEMOPREVENTIVE AND CHEMOTHERAPEUTIC POTENTIALS OF LUTEOLIN VIA REGULATION OF OXIDATIVE STRESS IN CASTRATION-RESISTANT PROSTATE CANCER Taku Naiki, Aya Naiki-Ito, Toshiki Etani, Keitaro Iida, Ryosuke Ando, Takashi Nagai, Noriyasu Kawai, Satoru Takahashi, and Takahiro Yasui Taku NaikiTaku Naiki More articles by this author , Aya Naiki-ItoAya Naiki-Ito More articles by this author , Toshiki EtaniToshiki Etani More articles by this author , Keitaro IidaKeitaro Iida More articles by this author , Ryosuke AndoRyosuke Ando More articles by this author , Takashi NagaiTakashi Nagai More articles by this author , Noriyasu KawaiNoriyasu Kawai More articles by this author , Satoru TakahashiSatoru Takahashi More articles by this author , and Takahiro YasuiTakahiro Yasui More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2056AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Identifying effective treatments for castration-resistant prostate cancer (CRPC) is important to prevent its persistent progression following androgen deprivation therapy. In a previous study, we showed that changes in the expression of genes concerned with oxidative stress regulation induced carcinogenesis and castration-resistant growth in prostate cancer. Herein, we investigated the chemotherapeutic potential of luteolin, an anti-oxidative flavonoid, on prostate cancer and CRPC. METHODS Male transgenic rats for adenocarcinoma of prostate (TRAP) were divided into three groups (n = 12 in each group) and fed the following for 8 weeks: basal diet, diet containing 20 ppm luteolin, and diet containing 100 ppm luteolin. Prostate tissues were collected from each animal for histopathological, gene, and protein expression analysis.PCai cells established from the TRAP prostate tumor and 22Rv1 cells were subcutaneously implanted in castrated and non-castrated nude mice, and in vivo tumor growth was analyzed. Subsequently, the effect of luteolin on cell proliferation and apoptosis in PCai1 and 22Rv1 cells was analyzed. RESULTS Luteolin decreased the incidence of adenocarcinoma and suppressed its progression from PIN to adenocarcinoma in TRAP. An increased apoptosis index with activation of caspase-3 and 7 was observed with high grade-PIN in the luteolin-fed TRAP. Production of reactive oxygen species and mRNA expression of the oxidative stress defense genes Gpx2 and Ho-1 were reduced by luteolin. Furthermore, luteolin inhibited tumor growth in the xenograft model via apoptosis induction and Gpx2 down-regulation. Luteolin also suppressed PCai1 and 22Rv1 cell proliferation in a dose-dependent manner in vitro by caspase-3 and 7-dependent apoptosis. CONCLUSIONS Luteolin decreased cell proliferation in a dose-dependent manner, and induced apoptosis with caspase activation in both, PCai1 and 22Rv1 cells. Dietary luteolin also suppressed tumor growth by increasing apoptosis and inhibiting angiogenesis in the PCai1 xenograft model. These results suggest that luteolin is a potential therapeutic agent for CRPC. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e854 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Taku Naiki More articles by this author Aya Naiki-Ito More articles by this author Toshiki Etani More articles by this author Keitaro Iida More articles by this author Ryosuke Ando More articles by this author Takashi Nagai More articles by this author Noriyasu Kawai More articles by this author Satoru Takahashi More articles by this author Takahiro Yasui More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Prostate Cancer Cell Viability and Migration in Serum and Prostate Conditioned Media from Moderate‐Intensity Exercise Trained Rats

Physical activity is associated with diminished risk of several cancers and preclinical studies suggest exercise training may alter tumor cell growth in certain tissues (e.g., adipose). We hypothesized that serum and prostate conditioned media (PCM) from moderate‐intensity exercise trained rats will decrease prostate cancer cell growth, while prostate 5α‐reductase 2 expression will decrease. We evaluated the effects of serum and PCM from moderate‐intensity exercise trained rats on prostate cancer cell viability and migration. In addition, we determined whether moderate‐intensity exercise training would modulate 5α‐reductase 2 protein expression, an essential component of androgen metabolism in prostate cancer. Male Copenhagen rats (~2–3 mo old) were randomly assigned to an exercise‐trained group (n = 10) and a sedentary control group (n = 10). The exercise‐trained rats ran on a motorized treadmill for 5 days/week at 15 m/min, 15° incline for 60 min/day for a 10‐ to 11‐week training period. Serum was collected from both rat groups, and used to supplement media at 5% concentration with and without 5% fetal bovine serum (FBS). Rat prostates were harvested, cut into two approximately equal sections with one section incubated with media for 24 hours to prepare PCM, and immunohistochemistry performed on the other section to quantify 5α‐reductase 2 expression. Dunning R‐3327 AT‐1 prostate cancer cells were grown in PCM, or media supplemented with either 5% serum from the exercise‐trained or sedentary groups with and without 5% FBS for 24–96 hours. Tumor cell viability and migration were determined using MTT and transwell migration assays, respectively. Serum or PCM from exercise‐trained rats did not significantly decrease cell viability compared to serum (e.g. 0.41 ± 0.04 vs. 0.50 ± 0.05 viable cell number, p = 0.14) or PCM (e.g. 0.40 ± 0.07 vs. 0.50 ± 0.08 viable cell number, p = 0.50; all at 48 hour incubation) from sedentary rats, respectively. However, the addition of FBS to serum from exercise‐trained rats significantly decreased cell viability compared to FBS and serum from sedentary rats (e.g. 0.49 ± 0.05 vs. 0.69 ± 0.06 viable cell number, p = 0.02; 48 hour incubation). Serum alone, serum and FBS, or PCM from exercise‐trained rats did not significantly impact cell migration compared to sedentary control (54.7 ± 3.3 vs. 64.2 ± 9.2 cells/field, p = 0.27; 29.3 ± 2.6 vs. 29.3 ± 2.5 cells/field, p &gt; 0.99; 55.9 ± 10.5 vs. 52.8 ± 8.1 cells/field, p = 0.82), respectively. 5α‐reductase 2 in the prostate was not significantly changed with exercise compared to sedentary group (0.87 ± 0.21 vs. 0.78 ± 0.18 positive cells/tissue area (μm2), p = 0.76). In conclusion, prior exercise status did not modify several key characteristics of prostate tumor cell growth and viability from conditioned media from host‐tissue (prostate) or serum in vitro. Whether exercise training alters similar prostate tumor cell growth characteristics in vivo is unknown.Support or Funding InformationAmerican Cancer Society RSG 14‐150‐1‐CCE (BJB)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Transforming the prostatic tumor microenvironment with oncolytic virotherapy

ABSTRACTProstate cancer (PCa) was estimated to have the second highest global incidence rate for male non-skin tumors and is the fifth most deadly in men thus mandating the need for novel treatment options. MG1-Maraba is a potent and versatile oncolytic virus capable of lethally infecting a variety of prostatic tumor cell lines alongside primary PCa biopsies and exerts direct oncolytic effects against large TRAMP-C2 tumors in vivo. An oncolytic immunotherapeutic strategy utilizing a priming vaccine and intravenously administered MG1-Maraba both expressing the human six-transmembrane antigen of the prostate (STEAP) protein generated specific CD8+ T-cell responses against multiple STEAP epitopes and resulted in functional breach of tolerance. Treatment of mice with bulky TRAMP-C2 tumors using oncolytic STEAP immunotherapy induced an overt delay in tumor progression, marked intratumoral lymphocytic infiltration with an active transcriptional profile and up-regulation of MHC class I. The preclinical data generated here offers clear rationale for clinically evaluating this approach for men with advanced PCa.