Oncogenic ETS fusions promote DNA damage and proinflammatory responses via pericentromeric RNAs in extracellular vesicles.

Aberrant expression of the E26 transformation-specific (ETS) transcription factors characterizes numerous human malignancies. Many of these proteins, including EWS:FLI1 and EWS:ERG fusions in Ewing sarcoma (EwS) and TMPRSS2:ERG in prostate cancer (PCa), drive oncogenic programs via binding to GGAA repeats. We report here that both EWS:FLI1 and ERG bind and transcriptionally activate GGAA-rich pericentromeric heterochromatin. The respective pathogen-like HSAT2 and HSAT3 RNAs, together with LINE, SINE, ERV, and other repeat transcripts, are expressed in EwS and PCa tumors, secreted in extracellular vesicles (EVs), and are highly elevated in plasma of patients with EwS with metastatic disease. High human satellite 2 and 3 (HSAT2,3) levels in EWS:FLI1- or ERG-expressing cells and tumors were associated with induction of G2/M checkpoint, mitotic spindle, and DNA damage programs. These programs were also activated in EwS EV-treated fibroblasts, coincident with accumulation of HSAT2,3 RNAs, proinflammatory responses, mitotic defects, and senescence. Mechanistically, HSAT2,3-enriched cancer EVs induced cGAS-TBK1 innate immune signaling and formation of cytosolic granules positive for double-strand RNAs, RNA-DNA, and cGAS. Hence, aberrantly expressed ETS proteins derepress pericentromeric heterochromatin, yielding pathogenic RNAs that transmit genotoxic stress and inflammation to local and distant sites. Monitoring HSAT2,3 plasma levels and preventing their dissemination may thus improve therapeutic strategies and blood-based diagnostics.

Combination Effects of Integrin-linked Kinase and Abelson Kinase Inhibition on Aberrant Mitosis and Cell Death in Glioblastoma Cells.

In cancer cells, inhibition of integrin-linked kinase (ILK) increases centrosome declustering causing mitotic arrest and cell death. Yet, not all cancer cells are susceptible to anti-ILK treatment alone. We investigate a combination drug strategy targeting ILK and another oncogenic kinase, Abelson kinase (ABL). Drug-concentration viability assays (i.e., MTT assays) indicate that ILK and ABL inhibitors in combination decreased the viability of glioblastoma cells over the ILK drug QLT-0267 alone. Combination strategies also increased aberrant mitoses and cell death over QLT-0267 alone. This was evident from an increase in mitotic arrest, apoptosis and a sub-G1 peak following FAC analysis. In vitro, ILK and ABL localized to the centrosome and the putative ILK kinase domain was important for this localization. Increased levels of cytosolic ABL are associated with its transformative abilities. ILK inhibitor effects on survival correlated with its ability to decrease cytosolic ABL levels and inhibit ABL's localization to mitotic centrosomes in glioblastoma cells. ILK inhibitor effects on ABL's centrosomal localization were reversed by the proteasomal inhibitor MG132 (a drug that inhibits ABL degradation). These results indicate that ILK regulates ABL at mitotic centrosomes and that combination treatments targeting ILK and ABL are more effective then QLT-0267 alone at decreasing the survival of dividing glioblastoma cells.

The "Ins and Outs" of Prostate Specific Membrane Antigen (PSMA) as Specific Target in Prostate Cancer Therapy.

Prostate-specific membrane antigen (PSMA) is expressed in epithelial cells of the prostate gland and is strongly upregulated in prostatic adenocarcinoma, with elevated expression correlating with metastasis, progression, and androgen independence. Because of its specificity, PSMA is a major target of prostate cancer therapy; however, detectable levels of PSMA are also found in other tissues, especially in salivary glands and kidney, generating bystander damage of these tissues. Antibody target therapy has been used with relative success in reducing tumor growth and prostate specific antigen (PSA) levels. However, since antibodies are highly stable in plasma, they have prolonged time in circulation and accumulate in organs with an affinity for antibodies such as bone marrow. For that reason, a second generation of PSMA targeted therapeutic agents has been developed. Small molecules and minibodies have had promising clinical trial results, but concerns about their specificity had arisen with side effects due to accumulation in salivary glands and kidneys. Herein we study the specificity of small molecules and minibodies that are currently being clinically tested. We observed a high affinity of these molecules for PSMA in prostate, kidney and salivary gland, suggesting that their effect is not prostate specific. The search for specific prostate target agents must continue so as to optimally treat patients with prostate cancer, while minimizing deleterious effects in other PSMA expressing tissues.

Inhibition of Scavenger Receptor Class B Type 1 (SR-B1) Expression and Activity as a Potential Novel Target to Disrupt Cholesterol Availability in Castration-Resistant Prostate Cancer.

There have been several studies that have linked elevated scavenger receptor class b type 1 (SR-B1) expression and activity to the development and progression of castration-resistant prostate cancer (CRPC). SR-B1 facilitates the influx of cholesterol to the cell from lipoproteins in systemic circulation. This influx of cholesterol may be important for many cellular functions, including the synthesis of androgens. Castration-resistant prostate cancer tumors can synthesize androgens de novo to supplement the loss of exogenous sources often induced by androgen deprivation therapy. Silencing of SR-B1 may impact the ability of prostate cancer cells, particularly those of the castration-resistant state, to maintain the intracellular supply of androgens by removing a supply of cholesterol. SR-B1 expression is elevated in CRPC models and has been linked to poor survival of patients. The overarching belief has been that cholesterol modulation, through either synthesis or uptake inhibition, will impact essential signaling processes, impeding the proliferation of prostate cancer. The reduction in cellular cholesterol availability can impede prostate cancer proliferation through both decreased steroid synthesis and steroid-independent mechanisms, providing a potential therapeutic target for the treatment of prostate cancer. In this article, we discuss and highlight the work on SR-B1 as a potential novel drug target for CRPC management.

Cobalt ions induce metabolic stress in synovial fibroblasts and secretion of cytokines/chemokines that may be diagnostic markers for adverse local tissue reactions to hip implants.

Adverse local tissue reactions (ALTRs) are a prominent cause of hip implant failure. ALTRs are characterized by aseptic necrosis and leukocyte infiltration of synovial tissue. The prevalence of ALTRs in hips with failing metal implants, with highest rates occurring in patients with metal-on-metal articulations, suggests a role for CoCrMo corrosion in ALTR formation. Although hypersensitivity reactions are the most accepted etiology, the precise cellular mechanism driving ALTR pathogenesis remains enigmatic. Here we show that cobalt ions released by failing hip implants induce mitochondrial stress and cytokine secretion by synovial fibroblasts: the presumptive initiators of ALTR pathogenesis. We found that in-vitro treatment of synovial fibroblasts with cobalt, but not chromium, generated gene expression changes indicative of hypoxia and mitophagy responses also observed in ALTRs biopsies. Inflammatory factors secreted by cobalt-exposed synovial fibroblasts were among those most concentrated in ALTR synovial fluid. Furthermore, both conditioned media from cobalt-exposed synovial fibroblasts, and synovial fluid from ALTRs patients, elicit endothelial activation and monocyte migration. Finally, we identify the IL16/CTACK ratio in synovial fluid as a possible diagnostic marker of ALTRs. Our results provide evidence suggesting that metal ions induce cell stress in synovial fibroblasts that promote an inflammatory response consistent with initiating ALTR formation. STATEMENT OF SIGNIFICANCE: We demonstrate that the cytotoxic effects of cobalt ions on the synovial cells (fibroblast) is sufficient to trigger inflammation on hip joints with metal implants. Cobalt ions affect mitochondrial function, leading to the auto phagocytosis of mitochondria and trigger a hypoxic response. The cell's hypoxic response includes secretion of cytokines that are capable of trigger inflammation by activating blood vessels and enhancing leukocyte migration. Among the secreted cytokines is IL-16, which is highly concentrated in the synovial fluid of the patients with adverse local tissue reactions and could be use as diagnostic marker. In conclusion we define the cells of the hip joint as key players in triggering the adverse reactions to hip implants and providing biomarkers for early diagnosis of adverse reactions to hip implants.

Perivascular lymphocytic aggregates in hip prosthesis-associated adverse local tissue reactions demonstrate Th1 and Th2 activity and exhausted CD8+ cell responses.

Hip implants are a successful solution for osteoarthritis; however, some individuals with metal-on-metal (MoM) and metal-on-polyethylene (MoP) prosthetics develop adverse local tissue reactions (ALTRs). While MoM and MoP ALTRs are presumed to be delayed hypersensitivity reactions to corrosion products, MoM- and MoP-associated ALTRs present with different histological characteristics. We compared MoM- and MoP-associated ALTRs histopathology with cobalt and chromium levels in serum and synovial fluid. We analyzed the gene expression levels of leukocyte aggregates and synovial fluid chemokines/cytokines to resolve potential pathophysiologic differences. In addition, we classified ALTRs from 79 patients according to their leukocyte infiltrates as macrophage-dominant, mixed, and lymphocyte-dominant. Immune-related transcript profiles from lymphocyte-dominant MoM- and MoP-associated ALTR patients with perivascular lymphocytic aggregates were similar. Cell signatures indicated predominantly macrophage, Th1 and Th2 lymphocytic infiltrate, with strong exhausted CD8+ signature, and low Th17 and B cell, relative to healthy lymph nodes. Lymphocyte-dominant ALTR-associated synovial fluid contained higher levels of induced protein 10 (IP-10), interleukin-1 receptor antagonist (IL-1RN), IL-8, IL-6, IL-16, macrophage inflammatory protein 1 (MIP-1α), IL-18, MCP-2, and lower cell-attracting chemokine levels, when compared with prosthetic revisions lacking ALTRs. In addition, the higher levels of IP-10, IL-8, IL-6, MIP-1α, and MCP-2 were observed within the synovial fluid of the lymphocyte-dominant ALTRs relative to the macrophage-dominant ALTRs. Not all cytokines/chemokines were detected in the perivascular aggregate transcripts, suggesting the existence of other sources in the affected synovia. Our results support the hypothesis of common hypersensitivity pathogenesis in lymphocyte-dominant MoM and MoP ALTRs. The exhausted lymphocyte signature indicates chronic processes and an impaired immune response, although the cause of the persistent T-cell activation remains unclear. The cytokine/chemokine signature of lymphocyte-dominant-associated ATLRs may be of utility for diagnosing this more aggressive pathogenesis.

ETS transcription factors as emerging drug targets in cancer.

The ETS family of proteins consists of 28 transcription factors, many of which have been implicated in development and progression of a variety of cancers. While one family member, ERG, has been rigorously studied in the context of prostate cancer where it plays a critical role, other ETS factors keep emerging as potential hallmark oncodrivers. In recent years, numerous studies have reported initial discoveries of small molecule inhibitors of ETS proteins and opened novel avenues for ETS-directed cancer therapies. This review summarizes the state of the art data on therapeutic targeting of ETS family members and highlights the corresponding drug discovery strategies.

Upregulation of Scavenger Receptor B1 Is Required for Steroidogenic and Nonsteroidogenic Cholesterol Metabolism in Prostate Cancer.

Aberrant cholesterol metabolism is increasingly appreciated to be essential for prostate cancer initiation and progression. Transcript expression of the high-density lipoprotein-cholesterol receptor scavenger receptor B1 (SR-B1) is elevated in primary prostate cancer. Hypothesizing that SR-B1 expression may help facilitate malignant transformation, we document increased SR-B1 protein and transcript expression in prostate cancer relative to normal prostate epithelium that persists in lethal castration-resistant prostate cancer (CRPC) metastasis. As intratumoral steroid synthesis from the precursor cholesterol can drive androgen receptor (AR) pathway activity in CRPC, we screened androgenic benign and cancer cell lines for sensitivity to SR-B1 antagonism. Benign cells were insensitive to SR-B1 antagonism, and cancer line sensitivity inversely correlated with expression levels of full-length and splice variant AR. In androgen-responsive CRPC cell model C4-2, SR-B1 antagonism suppressed cholesterol uptake, de novo steroidogenesis, and AR activity. SR-B1 antagonism also suppressed growth and viability and induced endoplasmic reticulum stress and autophagy. The inability of exogenous steroids to reverse these effects indicates that AR pathway activation is insufficient to overcome cytotoxic stress caused by a decrease in the availability of cholesterol. Furthermore, SR-B1 antagonism decreased cholesterol uptake, growth, and viability of the AR-null CRPC cell model PC-3, and the small-molecule SR-B1 antagonist block lipid transport-1 decreased xenograft growth rate despite poor pharmacologic properties. Overall, our findings show that SR-B1 is upregulated in primary and castration-resistant disease and is essential for cholesterol uptake needed to drive both steroidogenic and nonsteroidogenic biogenic pathways, thus implicating SR-B1 as a novel and potentially actionable target in CRPC. SIGNIFICANCE: These findings highlight SR-B1 as a potential target in primary and castration-resistant prostate cancer that is essential for cholesterol uptake needed to drive steroidogenic and nonsteroidogenic biogenic pathways.

Development of a microfluidic platform for size-based hydrodynamic enrichment and PSMA-targeted immunomagnetic isolation of circulating tumour cells in prostate cancer.

Efforts to further improve the clinical management of prostate cancer (PCa) are hindered by delays in diagnosis of tumours and treatment deficiencies, as well as inaccurate prognoses that lead to unnecessary or inefficient treatments. The quantitative and qualitative analysis of circulating tumour cells (CTCs) may address these issues and could facilitate the selection of effective treatment courses and the discovery of new therapeutic targets. Therefore, there is much interest in isolation of elusive CTCs from blood. We introduce a microfluidic platform composed of a multiorifice flow fractionation (MOFF) filter cascaded to an integrated microfluidic magnetic (IMM) chip. The MOFF filter is primarily employed to enrich immunomagnetically labeled blood samples by size-based hydrodynamic removal of free magnetic beads that must originally be added to samples at disproportionately high concentrations to ensure the efficient immunomagnetic labeling of target cancer cells. The IMM chip is then utilized to capture prostate-specific membrane antigen-immunomagnetically labeled cancer cells from enriched samples. Our preclinical studies showed that the proposed method can selectively capture up to 75% of blood-borne PCa cells at clinically-relevant low concentrations (as low as 5 cells/ml), with the IMM chip showing up to 100% magnetic capture capability.

Moving beyond panaceas in fisheries governance.

In fisheries management-as in environmental governance more generally-regulatory arrangements that are thought to be helpful in some contexts frequently become panaceas or, in other words, simple formulaic policy prescriptions believed to solve a given problem in a wide range of contexts, regardless of their actual consequences. When this happens, management is likely to fail, and negative side effects are common. We focus on the case of individual transferable quotas to explore the panacea mindset, a set of factors that promote the spread and persistence of panaceas. These include conceptual narratives that make easy answers like panaceas seem plausible, power disconnects that create vested interests in panaceas, and heuristics and biases that prevent people from accurately assessing panaceas. Analysts have suggested many approaches to avoiding panaceas, but most fail to conquer the underlying panacea mindset. Here, we suggest the codevelopment of an institutional diagnostics toolkit to distill the vast amount of information on fisheries governance into an easily accessible, open, on-line database of checklists, case studies, and related resources. Toolkits like this could be used in many governance settings to challenge users' understandings of a policy's impacts and help them develop solutions better tailored to their particular context. They would not replace the more comprehensive approaches found in the literature but would rather be an intermediate step away from the problem of panaceas.

Statin use and survival in patients with metastatic castration-resistant prostate cancer treated with abiraterone or enzalutamide after docetaxel failure: the international retrospective observational STABEN study.

BACKGROUND: Statins may potentiate the effects of anti-hormonal agents for metastatic castration-resistant prostate cancer (mCRPC) through further disruption of essential steroidogenic processes. We investigated the effects of statin use on clinical outcomes in patients with mCRPC receiving abiraterone or enzalutamide. MATERIALS AND METHODS: This was a retrospective multicenter study including patients that received abiraterone or enzalutamide for mCRPC. The effect of concurrent statin use on outcomes was evaluated. The associations of statins with early (≤12 weeks) prostate-specific antigen (PSA) declines (> 30%), cancer-specific survival and overall survival (OS) were evaluated after controlling for known prognostic factors. RESULTS: Five hundred and ninety-eight patients treated with second-line abiraterone or enzalutamide after docetaxel for mCRPC were included. A total of 199 men (33.3%) received statins during abiraterone/enzalutamide treatment. Median OS was 20.8 months (95% CI = 18.3-23.2) for patients who received statins, versus 12.9 months (95% CI = 11.4-14.6) for patients who did not receive statins (P < 0.001). After adjusting for age, alkaline phosphatase, PSA, neutrophil-to-lymphocytes ratio, Charlson comorbidity score, Gleason score, visceral disease, hemoglobin, opiate use and abiraterone versus enzalutamide treatment, the use of statin therapy was associated with a 53% reduction in the overall risk of death (hazard ratio [HR] = 0.47; 95% CI = 0.35-0.63; P < 0.001). Statin use was also associated with a 63% increased odds of a > 30% PSA decline within the first 12 weeks of treatment (OR = 1.63; 95% CI = 1.03-2.60; P = 0.039). CONCLUSIONS: In this retrospective cohort, statin use was significantly associated with both prolonged OS and cancer-specific survival and increased early > 30% PSA declines. Prospective validation is warranted.

East Indian Sandalwood Oil Is a Phosphodiesterase Inhibitor: A New Therapeutic Option in the Treatment of Inflammatory Skin Disease.

Cyclic adenosine monophosphate phosphodiesterases (PDEs) regulate pro-inflammatory cytokine production. One isoform, PDE4, is overactive in chronic relapsing inflammatory skin diseases: psoriasis and eczema/atopic dermatitis, and in several cancers. East Indian sandalwood oil (EISO) has significant anti-inflammatory properties. Here, we report that 75% of pediatric eczema/atopic dermatitis patients treated with topical EISO formulations achieved a >50% reduction in their Eczema Area and Severity Index score. EISO treatment of a psoriasis model reduced PDE4 expression and reversed histopathology. EISO directly inhibited PDE enzymatic activity in vitro. In lipopolysaccharide-stimulated human dermal fibroblast, BEAS-2B, A549, and THP-1 cells, EISO suppressed total cellular PDE activity, PDE4, and 7 transcript levels, nuclear factor kappa B (NF-κB) activation, and pro-inflammatory cytokines/chemokine production. These results suggest that EISO anti-inflammatory activity is mediated through suppressing PDE activity, thus facilitating cAMP-regulated inhibition of NF-κB and indicate EISO as an attractive natural therapeutic for chronic and acute inflammatory disorders.

Semaphorin 3 C drives epithelial-to-mesenchymal transition, invasiveness, and stem-like characteristics in prostate cells.

Prostate cancer (PCa) is among the most commonly-occurring cancers worldwide and a leader in cancer-related deaths. Local non-invasive PCa is highly treatable but limited treatment options exist for those with locally-advanced and metastatic forms of the disease underscoring the need to identify mechanisms mediating PCa progression. The semaphorins are a large grouping of membrane-associated or secreted signalling proteins whose normal roles reside in embryogenesis and neuronal development. In this context, semaphorins help establish chemotactic gradients and direct cell movement. Various semaphorin family members have been found to be up- and down-regulated in a number of cancers. One family member, Semaphorin 3 C (SEMA3C), has been implicated in prostate, breast, ovarian, gastric, lung, and pancreatic cancer as well as glioblastoma. Given SEMA3C's roles in development and its augmented expression in PCa, we hypothesized that SEMA3C promotes epithelial-to-mesenchymal transition (EMT) and stem-like phenotypes in prostate cells. In the present study we show that ectopic expression of SEMA3C in RWPE-1 promotes the upregulation of EMT and stem markers, heightened sphere-formation, and cell plasticity. In addition, we show that SEMA3C promotes migration and invasion in vitro and cell dissemination in vivo.

Discovery and characterization of small molecules targeting the DNA-binding ETS domain of ERG in prostate cancer.

Genomic alterations involving translocations of the ETS-related gene ERG occur in approximately half of prostate cancer cases. These alterations result in aberrant, androgen-regulated production of ERG protein variants that directly contribute to disease development and progression. This study describes the discovery and characterization of a new class of small molecule ERG antagonists identified through rational in silico methods. These antagonists are designed to sterically block DNA binding by the ETS domain of ERG and thereby disrupt transcriptional activity. We confirmed the direct binding of a lead compound, VPC-18005, with the ERG-ETS domain using biophysical approaches. We then demonstrated VPC-18005 reduced migration and invasion rates of ERG expressing prostate cancer cells, and reduced metastasis in a zebrafish xenograft model. These results demonstrate proof-of-principal that small molecule targeting of the ERG-ETS domain can suppress transcriptional activity and reverse transformed characteristics of prostate cancers aberrantly expressing ERG. Clinical advancement of the developed small molecule inhibitors may provide new therapeutic agents for use as alternatives to, or in combination with, current therapies for men with ERG-expressing metastatic castration-resistant prostate cancer.

East Indian Sandalwood Oil (EISO) Alleviates Inflammatory and Proliferative Pathologies of Psoriasis.

Psoriasis, a chronic inflammatory skin disease marked by hyper proliferation and aberrant differentiation of keratinocytes, affects 2-3% of the world's population. Research into the pathogenesis of psoriasis has been hampered by the lack of models that accurately reflect the biology of the psoriatic phenotype. We have previously reported that East Indian Sandalwood oil (EISO) has significant anti-inflammatory properties in skin models and hypothesized that EISO might provide therapeutic benefit to psoriasis patients due to its anti-inflammatory and anti-proliferative properties. Here we present interim results from an on-going proof-of-concept Phase 2 clinical trial in which topically applied EISO is demonstrating to be well tolerated and helpful in alleviating mild to moderate psoriasis symptoms. This led us to evaluate the ability of EISO to affect the psoriatic phenotype using MatTek Corporation reconstituted organotypic psoriatic and normal human skin models. EISO had no impact on the phenotype of the normal skin tissue model, however, EISO treatment of the psoriasis tissue model reverted psoriatic pathology as demonstrated by histologic characterization and expression of keratinocyte proliferation markers, Ki67 and psoriasin. These phenotypic affects correlated with suppressed production of ENA-78, IL-6, IL-8, MCP-1, GM-CSF, and IL-1ß. Demonstration of the ability of EISO to abrogate these psoriasis symptoms in well-characterized in vitro psoriatic tissue models, supports the hypothesis that the clinically observed symptom alleviation is due to suppression of intrinsic tissue inflammation reactions in afflicted lesions. This study presents a systematic approach to further study the underlying mechanisms that cause psoriasis, and presents data supporting the potential of EISO as a new ethnobotanical therapeutic concept to help direct and accelerate the development of more effective therapies.

Alternative RNA splicing of the MEAF6 gene facilitates neuroendocrine prostate cancer progression.

Although potent androgen receptor pathway inhibitors (ARPI) improve overall survival of metastatic prostate cancer patients, treatment-induced neuroendocrine prostate cancer (t-NEPC) as a consequence of the selection pressures of ARPI is becoming a more common clinical issue. Improved understanding of the molecular biology of t-NEPC is essential for the development of new effective management approaches for t-NEPC. In this study, we identify a splice variant of the MYST/Esa1-associated factor 6 (MEAF6) gene, MEAF6-1, that is highly expressed in both t-NEPC tumor biopsies and neuroendocrine cell lines of prostate and lung cancers. We show that MEAF6-1 splicing is stimulated by neuronal RNA splicing factor SRRM4. Rather than inducing neuroendocrine trans-differentiation of cells in prostate adenocarcinoma, MEAF6-1 upregulation stimulates cell proliferation, anchorage-independent cell growth, invasion and xenograft tumor growth. Gene microarray identifies that these MEAF6-1 actions are in part mediated by the ID1 and ID3 genes. These findings suggest that the MEAF6-1 variant does not induce neuroendocrine differentiation of prostate cancer cells, but rather facilitates t-NEPC progression by increasing the proliferation rate of cells that have acquired neuroendocrine phenotypes.

Paracrine sonic hedgehog signaling contributes significantly to acquired steroidogenesis in the prostate tumor microenvironment.

Despite the substantial benefit of androgen deprivation therapy (ADT) for metastatic prostate cancer, patients often progress to castration-resistant disease (CRPC) that is more difficult to treat. CRPC is associated with renewed androgen receptor activity in tumor cells and restoration of tumor androgen levels through acquired intratumoral steroidogenesis (AIS). Although prostate cancer (PCa) cells have been shown to have steroidogenic capability in vitro, we previously found that benign prostate stromal cells (PrSCs) can also synthesize testosterone (T) from an adrenal precursor, DHEA, when stimulated with a hedgehog (Hh) pathway agonist, SAG. Here, we show exposure of PrSCs to a different Smoothened (Smo) agonist, Ag1.5, or to conditioned medium from sonic hedgehog overexpressing LNCaP cells induces steroidogenic enzyme expression in PrSCs and significantly increases production of T and its precursor steroids in a Smo-dependent manner from 22-OH-cholesterol substrate. Hh agonist-/ligand-treated PrSCs produced androgens at a rate similar to or greater than that of PCa cell lines. Likewise, primary bone marrow stromal cells became more steroidogenic and produced T under the influence of Smo agonist. Treatment of mice bearing LNCaP xenografts with a Smo antagonist, TAK-441, delayed the onset of CRPC after castration and substantially reduced androgen levels in residual tumors. These outcomes support the idea that stromal cells in ADT-treated primary or metastatic prostate tumors can contribute to AIS as a consequence of a paracrine Hh signaling microenvironment. As such, Smo antagonists may be useful for targeting prostate tumor stromal cell-derived AIS and delaying the onset of CRPC after ADT.

The retinoblastoma protein regulates hypoxia-inducible genetic programs, tumor cell invasiveness and neuroendocrine differentiation in prostate cancer cells.

Loss of tumor suppressor proteins, such as the retinoblastoma protein (Rb), results in tumor progression and metastasis. Metastasis is facilitated by low oxygen availability within the tumor that is detected by hypoxia inducible factors (HIFs). The HIF1 complex, HIF1α and dimerization partner the aryl hydrocarbon receptor nuclear translocator (ARNT), is the master regulator of the hypoxic response. Previously, we demonstrated that Rb represses the transcriptional response to hypoxia by virtue of its association with HIF1. In this report, we further characterized the role Rb plays in mediating hypoxia-regulated genetic programs by stably ablating Rb expression with retrovirally-introduced short hairpin RNA in LNCaP and 22Rv1 human prostate cancer cells. DNA microarray analysis revealed that loss of Rb in conjunction with hypoxia leads to aberrant expression of hypoxia-regulated genetic programs that increase cell invasion and promote neuroendocrine differentiation. For the first time, we have established a direct link between hypoxic tumor environments, Rb inactivation and progression to late stage metastatic neuroendocrine prostate cancer. Understanding the molecular pathways responsible for progression of benign prostate tumors to metastasized and lethal forms will aid in the development of more effective prostate cancer therapies.

An integrated microfluidic chip for immunomagnetic detection and isolation of rare prostate cancer cells from blood.

The quantitative and qualitative analysis of circulating tumor cells (CTCs) has the potential to improve the clinical management of several cancers, including prostate cancer. As such, there is much interest in the isolation of CTCs from the peripheral blood of cancer patients. We report the design, fabrication, and proof-of-principle testing of an integrated permalloy-based microfluidic chip for immunomagnetic isolation of blood-borne prostate cancer cells using an antibody targeting prostate surface membrane antigen (PSMA). The preliminary results using spiked blood samples indicate that the proposed device is consistently capable of isolating prostate cancer cells with high sensitivity (up to 98 %) at clinically relevant low concentrations (down to 20 cells/mL) and an acceptable throughput (100 µL/min).

The Effects of the Organic Flame-Retardant 1,2-Dibromo-4-(1,2-dibromoethyl) Cyclohexane (TBECH) on Androgen Signaling in Human Prostate Cancer Cell Lines.

The effects of the organic flame retardant 1,2-Dibromo-4-(1,2-dibromoethyl) cyclohexane (TBECH) on androgen receptor target gene expression were examined in the human LNCaP prostate cancer cell line. While γ-/δ-TBECH alone led to a significant increase in prostate-specific antigen (PSA) mRNA accumulation, both the α-/-TBECH and γ-/δ-TBECH mixtures repressed androgen-inducible PSA mRNA and protein accumulation in human LNCaP cells. Thus, we hypothesize that isomeric mixtures of TBECH may act as partial agonists of the androgen receptor.