Human Prostate Epithelial Cell Line Research Articles

Inhibition of autophagy aggravated 4-nitrophenol-induced oxidative stress and apoptosis in NHPrE1 human normal prostate epithelial progenitor cells

4-Nitrophenol (PNP), a well-established human carcinogen, has been proven to have detrimental effects on reproductive system of male rats in previous studies. The molecular mechanisms involved PNP-induced damage remain to be established. Autophagy can exert protective effects on various cytotoxic factors that induce injury. In the present study, we aim to investigate whether autophagy is induced by PNP and the function of autophagy in PNP-induced injury in NHPrE1, a normal human prostate epithelial progenitor cell line. Our results indicate that PNP induced oxidative stress as evidenced by increased MDA levels and decreased activity of SOD and GSH-Px. PNP also increased apoptosis of NHPrE1 cells as evidenced by western blot and Hoechst 33258 staining and activated autophagy in NHPrE1 cells detected by RT-PCR and western blot. Inhibition of autophagy by 3-MA further increased PNP-induced oxidative stress and apoptosis of NHPrE1 cells. We also found that PNP-induced apoptosis was suppressed by N-acetylcysteine, suggesting oxidative stress may play an important role in PNP cytotoxicity. Furthermore, phosphorylation of mTOR protein was inhibited by PNP, indicating that PNP might induce autophagy in NHPrE1 cells via inhibiting mTOR pathway. In conclusion, these results suggest that activation of autophagy should play a protective role in PNP-induced oxidative stress and apoptosis of NHPrE1 cells, which might be mediated through mTOR pathway.

Zinc Induces Lipopolysaccharide-Mediated Upregulation of Human β-defensin-2 in Human Prostate Epithelial Cells

Zinc is considered to be one of the most essential trace minerals for the immune system. High levels of prostatic zinc are associated with prostatic antimicrobial activities. Zinc-deficient individuals experience increased susceptibility to a variety of pathogens. Zinc appears to play a crucial role in maintaining prostate health. This study aimed to clarify the role of zinc in human prostate epithelial cell defense against bacterial infection. To explore the effect of zinc on lipopolysaccharide (LPS)-mediated induction of human β-defensin-2 (HBD-2), the normal human prostate epithelial cell lines (RWPE-1) were co-treated with zinc/LPS and HBD-2 mRNA expression was quantitated by the reverse transcription polymerase chain reaction (RT-PCR). We also conducted a Western blot analysis to determine whether zinc stimulates p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase-1 and -2 (ERK1/2) signaling pathways. To investigate the involvement of the p38MAPK and ERK1/2 signaling pathways in zinc-mediated upregulation of HBD-2, quantitative real-time PCR and immunocytochemical staining were then used to quantify HBD-2 mRNA expression and protein production, respectively, which was treated with either U0126 (ERK1/2 inhibitor) or SB203580 (p38MAPK inhibitor) prior to each analysis of HBD-2.

MP48-11 THE EFFECT OF MORPHINE AND ITS INHIBITORS ON RT112 BLADDER CANCER CELL GROWTH

You have accessJournal of UrologyBladder Cancer: Basic Research & Pathophysiology II1 Apr 2017MP48-11 THE EFFECT OF MORPHINE AND ITS INHIBITORS ON RT112 BLADDER CANCER CELL GROWTH Brian Birch, Bashir Lwaleed, Alan Cooper, Phil Harper, and Iliana Giatsidou Brian BirchBrian Birch More articles by this author , Bashir LwaleedBashir Lwaleed More articles by this author , Alan CooperAlan Cooper More articles by this author , Phil HarperPhil Harper More articles by this author , and Iliana GiatsidouIliana Giatsidou More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.1492AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Clinical studies suggest opioid use affects rates of metastasis in breast and prostate cancer. Results are variable and conflicting. This investigation tested the effects of morphine on bladder cancer cell growth in vitro and examined whether those effects can be reversed with receptor blockers. METHODS Cell lines: Adherent epithelial cell lines were used:RT-112 - Human urinary bladder transitional carcinoma cell lines, histological grade G2 (moderately differentiated). PNT2 - Normal (virally transformed) Human prostate epithelial cell line. These cells were grown using routine cell culture techniques supplemented with 10% foetal calf serum and antibiotics. Proliferation assay: The assay recorded residual viable biomass (RVB) 72 hours into exposure with the agent being studied RESULTS Doubling dilution of morphine produced a bell-shaped curve, with high (non-clinical)concentrations inhibiting growth, followed by stimulation between 100 and 1 microgram per ml (clinically relevant concentrations shown in Figure 1 green circle), reverting to control levels thereafter. The near-normal PNT-2 cell line showed minimal responsiveness to morphine Incubation with naloxone alone has little effect on residual biomass compared to controls Conversely, pre-incubating with a fixed concentration of Naloxone, then titrating morphine across the plate showed stimulation to decrease as the relative proportion of blocker rises (Figure 2) CONCLUSIONS Morphine in clinically relevant concentrations stimulated growth in the RT-112 transitional carcinoma cell line, as assessed by the MTT assay. This effect was minimal under the same conditions using the virally transformed normal prostate cell line (PNT2). Treating cells with the antagonists Naloxone or Naltrexone inhibited the action of morphine. The tentative implication is that using opioids in cancer patients despite their important role in pain relief may also tend to promote tumour growth. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e640-e641 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Brian Birch More articles by this author Bashir Lwaleed More articles by this author Alan Cooper More articles by this author Phil Harper More articles by this author Iliana Giatsidou More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Role of connexin 43 in cadmium-induced proliferation of human prostate epithelial cells.

Connexins (Cxs), the subunits of gap junction channels, are involved in many physiological processes. Aberrant control of Cxs and gap junction intercellular communication may contribute to many diseases, including the promotion of cancer. Cd exposure is associated with increased risk of human prostate cancer and benign prostatic hyperplasia. The roles of Cxs in the effects of Cd on the prostate have, however, not been reported previously. In this study, the human prostate epithelial cell line RWPE-1 was exposed to Cd. A low dose of Cd stimulated cell proliferation along with a lower degree of gap junction intercellular communication and an elevated level of the protein Cx43. Cd exposure increased the levels of intracellular Ca2+ and phosphorylated Cx43 at the Ser368 site. Knockdown of Cx43 using siRNA blocked Cd-induced proliferation and interfered with the Cd-induced changes in the protein levels of cyclin D1, cyclin B1, p27Kip1 (p27) and p21Waf1/Cip1 (p21). The increase in Cx43 expression induced by Cd was presumably mediated by the androgen receptor, because it was abolished upon treatment with the androgen receptor antagonist, flutamide. Thus, a low dose of Cd promotes cell proliferation in RWPE-1, possibly mediated by Cx43 expression through an effect on cell cycle-associated proteins. Cx43 might be a target for prostatic diseases associated with Cd exposure. Copyright © 2017 John Wiley & Sons, Ltd.

Inhibitory effect of oncolytic adenovirus ZD55-special AT rich sequence binding protein 1 on proliferation and invasion of andragon-independent prostate cancer DU145 cells

Objective To investigate the suppressive effect of oncolytic adenovirus ZD55-special AT rich sequence binding protein 1 (SATB1) expressing small hairpin RNA targeting SATB1 gene on growth and invasion of prostate cancer DU145 cells. Methods The oncolytic adenovirus ZD55-SATB1 was constructed and identifies. The inhibitory effect of ZD55-SATB1 on SATB1 expression was evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting analysis at 72 h after infection of DU145 cells with ZD55-SATB1 at a MOI of 10. The cytotoxicity of ZD55-SATB1 was detected by cell counting kit-8 (CCK-8) assay and crystal violet staining assay. Cell invasion was detected by Matrigel invasion assay. The expression of E1A protein in DU145 cell lines infected with viruses respectively was detected by Western blotting. Results The oncolytic adenoviruses ZD55-SATB1 were successfully constructed and identified. RT-PCR and Western blotting assay showed that ZD55-SATB1 could significantly decrease the expression of SATB1 in DU145 cells (P<0.05). The relative protein levels of E1A in DU145 cells treated with ZD55-SATB1 were significantly higher than those in human normal prostate epithelial cell line PZ-HPV-7 cells (P<0.01), which indicated cancer specificity of ZD55-SATB1 for prostate cance cells. Crystal violet staining assay showed that ZD55-SATB1 exhibited obvious cytotoxicity in DU145 cells. The cytopathic effect of ZD55-SATB1 was much stronger than that of ZD55-enhanced green fluorescent protein (EGFP) and Ad-SATB1. CCK-8 assay showed that cell viability of ZD55-SATB1 group [(31.60±3.31)%] was significantly lower than that in ZD55-EGFP group [(61.70±2.42)%, P=0.025] and Ad-SATB1 group [(82.40±3.54)%, P=0.017] for DU145 cells after 4 days. Transwell cell invasive experiment showed that the number of cells that invaded the membrane in ZD55-SATB1 group was (61.30±17.25) cells, significantly less than that in the Ad-SATB1 group [(170.10±25.44) cells, P=0.043], the ZD55-EGFP group [(295.40±23.36) cells, P=0.013] and the PBS group [(490.50±33.36) cells, P=0.009]. Conclusion Oncolytic adenovirus ZD55-SATB1 could effectively knockdown the SATB1 expression in DU145 cells, and dramatically inhibit proliferation and invasion of DU145 cells. Key words: Oncolytic adenovirus; Special AT rich sequence binding protein 1; Proliferation; Invasion

Zinc induces LPS-mediated upregulation of HBD-2 via ERK1/2 and p38MAPK signaling pathways in human prostate epithelial cells

ABSTRACTThis study aimed to clarify the role of zinc in human prostate epithelial cell defense against bacterial infection. To explore the effect of zinc on lipopolysaccharide (LPS)-mediated induction of human β-defensin-2 (HBD-2), the normal human prostate epithelial cell lines (RWPE-1) were co-treated with zinc/LPS and HBD-2 mRNA expression was quantitated by the reverse transcription polymerase chain reaction (RT-PCR). We also conducted a Western blot analysis to determine whether zinc stimulates p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase-1 and -2 (ERK1/2) signaling pathways. To investigate the involvement of the p38MAPK and ERK1/2 signaling pathways in zinc-mediated upregulation of HBD-2, quantitative real-time PCR and immunocytochemical staining were then used to quantify HBD-2 mRNA expression and protein production, respectively, which was treated with either U0126 (ERK1/2 inhibitor) or SB203580 (p38MAPK inhibitor) prior to each analysis of HBD-2. Cotreatment of RWPE-1 cells with zinc/LPS-upregulated HBD-2 expression to an even greater extent than either LPS alone or zinc alone. Moreover, the treatment of RWPE-1 cells with zinc significantly increased both the total and phosphorylated forms of ERK1/2 and p38MAPK. ERK1/2 and p38MAPK signaling via the inhibitors U0126 and SB203580 pharmacologically inhibited zinc-mediated upregulation of HBD-2. These results strongly suggest that zinc plays an important role in the immune response of the prostate. Furthermore, we demonstrate that zinc-mediated upregulation of HBD-2 expression upon bacterial infection of prostate epithelial cells involves the ERK1/2 and p38MAPK signaling pathways.

TGF-β Effects on Prostate Cancer Cell Migration and Invasion Require FosB.

Activator Protein-1 (AP-1) family (cJun, JunB, JunD, cFos, FosB, Fra1, and Fra2) plays a central role in the transcriptional regulation of many genes that are associated with cell proliferation, differentiation, migration, metastasis, and survival. Many oncogenic signaling pathways converge at the AP-1 transcription complex. Transforming growth factor beta (TGF-β) is a multifunctional regulatory cytokine that regulates many aspects of cellular function, including cellular proliferation, differentiation, migration, apoptosis, adhesion, angiogenesis, immune surveillance, and survival. This study investigated, the role of FOS proteins in TGF-β signaling in prostate cancer cell proliferation, migration, and invasion. Steady state expression levels of FOS mRNA and proteins were determined using RT-PCR and western blotting analyses. DU145 and PC3 prostate cancer cells were exposed to TGF-β1 at varying time and dosage, RT-PCR, western blot, and immunofluorescence analyses were used to determine TGF-β1 effect on FOS mRNA and protein expression levels as well as FosB subcellular localization. Transient silencing of FosB protein was used to determine its role in cell proliferation, migration, and invasion. Our data show that FOS mRNA and proteins were differentially expressed in human prostate epithelial (RWPE-1) and prostate cancer cell lines (LNCaP, DU145, and PC3). TGF-β1 induced the expression of FosB at both the mRNA and protein levels in DU145 and PC3 cells, whereas cFos and Fra1 were unaffected. Immunofluorescence analysis showed an increase in the accumulation of FosB protein in the nucleus of PC3 cells after treatment with exogenous TGF-β1. Selective knockdown of endogenous FosB by specific siRNA did not have any effect on cell proliferation in PC3 and DU145 cells. However, basal and TGF-β1- and EGF-induced cell migration was significantly reduced in DU145 and PC3 cells lacking endogenous FosB. TGF-β1- and EGF-induced cell invasion were also significantly decreased after FosB knockdown in PC3 cells. Our data suggest that FosB is required for migration and invasion in prostate cancer cells. We also conclude that TGF-β1 effect on prostate cancer cell migration and invasion may be mediated through the induction of FosB. Prostate 77:72-81, 2017. © 2016 Wiley Periodicals, Inc.

Abstract 1849: CXXC5 is overexpressed in human prostate epithelial cancer cell lines in culture and human prostate cancer tissue

Abstract Background: CXXC5 encodes a retinoid-inducible nuclear factor that plays an essential role in human hematopoiesis (1, 2). We have previously identified the differential expression of this gene in rat cancer cell lines with different cancer phenotypes (3). However, knowledge on the expression of this gene in human prostate cell lines or tissue is lacking, both at the transcript and protein level. Methods: Prospective study conducted between January-2012 through June-2015 at the University of Cartagena, Colombia. Expression of CXXC5 was evaluated by quantitative PCR, both in prostate cancer cell lines and tissue biopsies from patients undergoing transrectal ultrasound-guided prostate needle biopsy for suspected prostate cancer (PCa). A total of 65 prostate tissue samples, consisting of 24 benign prostatic tissue biopsies and 41 prostate cancer tissue biopsies were included in the study. Transcript levels in individual biopsies from each group were normalized to transcript levels of beta-actin of the corresponding sample and compared. The protein expression level of CXXC5 was analyzed by immunohistochemistry in benign and malignant prostate tissue. A final score was determined by multiplying the highest intensity of staining by the mean percentage of positive cells stained to yield a value between 0 and 300 for each case. For statistical analysis we compared parameters between group of cases with PCa and without PCa. This study was approved by the Ethical Review Board of the academic institution. Results: CXXC5 transcript expression levels were significantly lower in immortalized non-tumoral prostate cell line PWR-1E compared to PCa cell lines: LNCaP (Fold change: 10.5, p = 0.001), and PC3 (Fold change: 2.8, p = 0.014). In prostate tissue we observed a significant higher expression in low grade prostate cancer compared to benign prostate tissue (p = 0.034). IHC evaluation showed that CXXC5 staining was higher in tissue samples from patients with prostate cancer compared to patients with benign disease (p = &amp;lt;0.001). In the prostate cancer group, immunostaining was also stronger in malignant acini than in adjacent, benign acini, within the same patient sample. Conclusions: CXXC5 exhibits differential expression in prostate cell lines with different cancer phenotypes and between cancer and benign prostate tissue. Additional studies are required to determine the biological and clinical significance of CXXC5 in prostate cancer.

NF-κB and androgen receptor variant 7 induce expression of SRD5A isoforms and confer 5ARI resistance.

Benign prostatic hyperplasia (BPH) is treated with 5α-reductase inhibitors (5ARI). These drugs inhibit the conversion of testosterone to dihydrotestosterone resulting in apoptosis and prostate shrinkage. Most patients initially respond to 5ARIs; however, failure is common especially in inflamed prostates, and often results in surgery. This communication examines a link between activation of NF-κB and increased expression of SRD5A2 as a potential mechanism by which patients fail 5ARI therapy. Tissue was collected from "Surgical" patients, treated specifically for lower urinary tract symptoms secondary to advanced BPH; and, cancer free transition zone from "Incidental" patients treated for low grade, localized peripheral zone prostate cancer. Clinical, molecular and histopathological profiles were analyzed. Human prostatic stromal and epithelial cell lines were genetically modified to regulate NF-κB activity, androgen receptor (AR) full length (AR-FL), and AR variant 7 (AR-V7) expression. SRD5A2 is upregulated in advanced BPH. SRD5A2 was significantly associated with prostate volume determined by Transrectal Ultrasound (TRUS), and with more severe lower urinary tract symptoms (LUTS) determined by American Urological Association Symptom Score (AUASS). Synthesis of androgens was seen in cells in which NF-κB was activated. AR-FL and AR-V7 expression increased SRD5A2 expression while forced activation of NF-κB increased all three SRD5A isoforms. Knockdown of SRD5A2 in the epithelial cells resulted in significant reduction in proliferation, AR target gene expression, and response to testosterone (T). In tissue recombinants, canonical NF-κB activation in prostatic epithelium elevated all three SRD5A isoforms and resulted in in vivo growth under castrated conditions. Increased BPH severity in patients correlates with SRD5A2 expression. We demonstrate that NF-κB and AR-V7 upregulate SRD5A expression providing a mechanism to explain failure of 5ARI therapy in BPH patients. Prostate 76:1004-1018, 2016. © 2016 Wiley Periodicals, Inc.

Hypoxia primes human normal prostate epithelial cells and cancer cell lines for the NLRP3 and AIM2 inflammasome activation.

The molecular mechanisms by which hypoxia contributes to prostatic chronic inflammation (PCI) remain largely unknown. Because hypoxia stimulates the transcriptional activity of NF-κB, which “primes” cells for inflammasome activation by inducing the expression of NLRP3 or AIM2 receptor and pro-IL-1β, we investigated whether hypoxia could activate the NLRP3 and AIM2 inflammasome in human normal prostate epithelial cells (PrECs) and cancer cell lines. Here we report that hypoxia (1% O2) treatment of PrECs, prostate cell lines, and a macrophage cell line (THP-1) increased the levels of NLRP3, AIM2, and pro-IL-1β. Further, hypoxia in cells potentiated activation of the NLRP3 and AIM2 inflammasome activity. Notably, hypoxia “primed” cells for NLRP3 and AIM2 inflammasome activation through stimulation of the NF-κB activity. Our observations support the idea that hypoxia in human prostatic tumors contributes to PCI, in part, by priming cells for the activation of NLRP3 and AIM2 inflammasome.

Iterative design of emetine-based prodrug targeting fibroblast activation protein (FAP) and dipeptidyl peptidase IV DPPIV using a tandem enzymatic activation strategy.

There is an urgent need to develop new agents for treating metastatic prostate cancer to overcome multiple drug resistance to the current standard targeted cancer therapy. Emetine is a highly cytotoxic natural product protein synthesis inhibitor, which is toxic to all cell types. Its cytotoxicity can be blocked by derivatizing its N-2' position. Thus emetine can be selectively delivered to cancer cells in the region of metastatic cancer as a prodrug that will be activated by an enzyme selectively overexpressed within the metastatic tumor microenvironment. In this work, we convert emetine to a prodrug activatable by the fibroblast activation protein (FAP), a serine protease overexpressed by the carcinoma associated fibroblasts. By using an iterative structure-activity relationship strategy, several peptidyl emetine prodrug analogs (1-11) were synthesized by chemical derivatization of emetine at its N-2' position and tested for in-vitro activation by FAP. The lead prodrug 11 is made up of a DPPIV activatable prodrug precursor 10 (Ala-Pro-PABC-Emetine) coupled to FAP substrate (Ala-Ser-Gly-Pro-Ala-Gly-Pro). Activation assays of the prodrugs were performed in purified FAP, DPPIV, FBS, and human serum and were analyzed by LCMS. In vitro cytotoxicity assays of these prodrugs are carried out in prostate (LNCaP, PC3) and breast (MCF7 and MDA-MB-231) cancer cell lines. The prodrugs are also tested in normal immortalized human prostatic epithelial cell line (PrEC). The lead FAP activated emetine prodrug 11 is activated to emetine in tandem by FAP and DPPIV in about 70% conversion within 24 hr. In prostate and breast cancer cell lines treated with prodrug 11, it is found to be equipotent with emetine in the presence of FAP and DPPIV. However, in the PrEC cell line grown in serum free media, prodrug 11 is more than 200-fold less cytotoxic than emetine in the absence of FAP and DPPIV. This FAP activated prodrug of cytotoxic agent emetine further shows the crucial role of the N-2' position of emetine in controlling its cytotoxicity. Significantly reduced toxicity observed in the PrEC cell line in the absence of FAP and DPPIV shows that prodrug 11 could be systemically delivered to regions of metastatic prostate cancer or other solid tumor for activation by cancer selective enzymes within the cancer microenvironment, such as FAP that is overexpressed by the carcinoma-associated fibroblasts. The two-step tandem enzymatic activation of prodrug 11 by FAP and DPPIV is a strategy for overcoming steric hindrance.

Abstract A34: Decline in Arylsulfatase B activates Wnt signaling by effects on DKK-3 methylation

Abstract Immunostaining and activity of the enzyme Arylsulfatase B (ARSB; N-acetylgalactosamine 4-sulfatase) were reduced in prostatic malignancies, and decline in ARSB was associated with higher Gleason score and biochemical recurrence in two prostate cancer tissue microarrays. Since the only known function of ARSB is to remove 4-sulfate groups from chondroitin 4-sulfate (C4S) and dermatan sulfate, a mechanism for this association of ARSB with more aggressive prostate cancer was unknown. Subsequent studies showed transcriptional effects of ARSB, mediated by reduced binding of galectin-3 to the more highly sulfated C4S present when ARSB was reduced. Decline in ARSB induced increased expression of the extracellular matrix proteoglycan versican, which has chondroitin 4-sulfate attachments and has been shown to be increased in more aggressive prostate cancers. The increase in versican was mediated by increased nuclear galectin-3 and AP-1 effects on the versican promoter. Other experiments following decline in ARSB showed increased expression of Wnt9A, mediated by increased nuclear galectin-3 and Sp1. These findings suggested that ARSB acted as a tumor suppressor gene and decline in ARSB enhanced tumor progression. Experiments were performed to address transcriptional mechanisms by which decline in ARSB and the accompanying increase in chondroitin 4-sulfation could activate Wnt signaling and lead to more aggressive prostate cancers. The impact of ARSB on Wnt signaling was evaluated in prostate tissue from the ARSB-null mouse, and human prostate stromal (WPMY-1, ATCC), epithelial (RWPE-1, ATCC), and stem (WPE-stem, ATCC) cell lines. The effects of ARSB on Wnt signaling were assessed by ELISA, Western blot, silencing by siRNA, ARSB overexpression, DNA methyltransferase (DNMT) activity assays, QRT-PCR, and measurements of promoter methylation. Decline in ARSB increased Wnt signaling, manifested by increases in nuclear beta-catenin, DNA-bound TCF-LEF, nuclear c-myc and cyclin D1. To determine if increased Wnt signaling was attributable to reduction of the inhibitory effect of Dickkopf (DKK), an established negative regulator of Wnt signaling and tumor suppressor, the expression of DKK 1-4 was determined by QRT-PCR. DKK-3 expression in the prostate cells following ARSB silencing and in the ARSB-null tissue was significantly reduced. ARSB overexpression increased the DKK-3 expression. DNA methyltransferase (DNMT) activity was significantly increased when ARSB was silenced, and reduced when ARSB was overexpressed. Expression of DNMT 1 and 3a was increased in the ARSB-null mouse prostate tissue and prostate cells, consistent with the decline in DKK-3 expression. Determinations of DKK-3 promoter methylation showed increased methylation following ARSB silencing and in the malignant prostate tissue. Hence, decline in ARSB activated Wnt signaling by increased methylation of DKK-3, leading to disinhibition of Wnt signaling, attributable to reduced binding of DKK-3 with the Frizzled - LRP5/6 receptor complex. These findings demonstrate an epigenetic mechanism whereby decline in ARSB increases Wnt signaling in prostate tissue and can lead to more aggressive prostate malignancy. Also, the role of ARSB as a tumor suppressor gene is supported by this demonstration of inverse effects of decline and overexpression of ARSB on Wnt signaling and on DNMT expression and activity. Experiments are ongoing to clarify the intermediates in the pathway by which ARSB affects DNMT expression. Note: This abstract was not presented at the conference. Citation Format: Sumit Bhattacharyya, Leo Feferman, Joanne Kramer Tobacman. Decline in Arylsulfatase B activates Wnt signaling by effects on DKK-3 methylation. [abstract]. In: Proceedings of the Fourth AACR International Conference on Frontiers in Basic Cancer Research; 2015 Oct 23-26; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2016;76(3 Suppl):Abstract nr A34.

The small leucine rich proteoglycan fibromodulin is overexpressed in human prostate epithelial cancer cell lines in culture and human prostate cancer tissue

Fibromodulin is a small leucine-rich proteoglycan important for extracellular matrix organization and essential for tissue repair in multiple organs. The main function of this proteoglycan is the regulation of collagen fibrillogenesis; however, more recently described roles for fibromodulin have expanded to include regulation of angiogenesis, reprogramming of human fibroblasts into pluripotent cells, modulation of TGF-β activity, inflammatory processes and association with metastatic phenotypes. Additionally, fibromodulin has been identified as a novel tumor-associated antigen in leukemia, lymphoma, and leiomyoma. Knowledge about its expression in the prostate is limited. Fibromodulin expression was analyzed in two different malignant and one non-tumorigenic prostatic cell lines in culture, and in benign and malignant human prostate tissue. Expression was analyzed by real time PCR, immunocytochemistry, and immunohistochemistry. DNA sequencing was performed on a PCR fragment amplified with primers specific for the FMOD gene from cDNA obtained from the cultured cell lines. Both immunostaining and real time PCR analysis of cell lines indicated that fibromodulin was differentially expressed in the cancerous cell lines compared to the non-tumorigenic cell line. Likewise, cancerous tissue expressed significantly higher levels of intracellular fibromodulin compared to matched, benign tissue from the same patients, as well as compared to tissue from patients with only benign disease. The expression of fibromodulin was higher in prostatic cancer cells (cell-lines and human tissue) than in normal/benign prostatic cells. Additional studies are required to determine the biological and clinical significance and whether this proteoglycan has a role in carcinogenesis of the prostate or in prostate cancer related inflammatory processes.

NF-κB and androgen receptor variant expression correlate with human BPH progression.

Benign prostatic hyperplasia (BPH) is a common, chronic progressive disease. Inflammation is associated with prostatic enlargement and resistance to 5α-reductase inhibitor (5ARI) therapy. Activation of the nuclear factor-kappa B (NF-κB) pathway is linked to both inflammation and ligand-independent prostate cancer progression. NF-κB activation and androgen receptor variant (AR-V) expression were quantified in transition zone tissue samples from patients with a wide range of AUASS from incidental BPH in patients treated for low grade, localized peripheral zone prostate cancer to advanced disease requiring surgical intervention. To further investigate these pathways, human prostatic stromal and epithelial cell lines were transduced with constitutively active or kinase dead forms of IKK2 to regulate canonical NF-κB activity. The effects on AR full length (AR-FL) and androgen-independent AR-V expression as well as cellular growth and differentiation were assessed. Canonical NF-κB signaling was found to be upregulated in late versus early stage BPH, and to be strongly associated with non-insulin dependent diabetes mellitus. Elevated expression of AR-variant 7 (AR-V7), but not other AR variants, was found in advanced BPH samples. Expression of AR-V7 significantly correlated with the patient AUASS and TRUS volume. Forced activation of canonical NF-κB in human prostatic epithelial and stromal cells resulted in elevated expression of both AR-FL and AR-V7, with concomitant ligand-independent activation of AR reporters. Activation of NF-κB and over expression of AR-V7 in human prostatic epithelial cells maintained cell viability in the face of 5ARI treatment. Activation of NF-κB and AR-V7 in the prostate is associated with increased disease severity. AR-V7 expression is inducible in human prostate cells by forced activation of NF-κB resulting in resistance to 5ARI treatment, suggesting a potential mechanism by which patients may become resistant to 5ARI therapy.

Expression of Beta-Defensin 131 Promotes an Innate Immune Response in Human Prostate Epithelial Cells.

Previously, using the Illumina HumanHT-12 microarray we found that β-defensin 131 (DEFB131), an antimicrobial peptide, is upregulated in the human prostate epithelial cell line RWPE-1 upon stimulation with lipoteichoic acid (LTA; a gram-positive bacterial component), than that in the untreated RWPE-1 cells. In the current study, we aimed to investigate the role of DEFB131 in RWPE-1 cells during bacterial infection. We examined the intracellular signaling pathways and nuclear responses in RWPE-1 cells that contribute to DEFB131 gene induction upon stimulation with LTA. Chromatin immunoprecipitation was performed to determine whether NF-κB directly binds to the DEFB131 promoter after LTA stimulation in RWPE-1 cells. We found that DEFB131 expression was induced by LTA stimulation through TLR2 and p38MAPK/NF-κB activation, which was evident in the phosphorylation of both p38MAPK and IκBα. We also found that SB203580 and Bay11-7082, inhibitors of p38MAPK and NF-κB, respectively, suppressed LTA-induced DEFB131 expression. The chromatin immunoprecipitation assay showed that NF-κB directly binds to the DEFB131 promoter, suggesting that NF-κB is a direct regulator, and is necessary for LTA-induced DEFB131 expression in RWPE-1 cells. Interestingly, with DEFB131 overexpression in RWPE-1 cells, the accumulation of mRNA and protein secretion of cytokines (IL-1α, IL-1β, IL-6, and IL-12α) and chemokines (CCL20, CCL22, and CXCL8) were significantly enhanced. In addition, DEFB131-transfected RWPE-1 cells markedly induced chemotactic activity in THP-1 monocytes. We concluded that DEFB131 induces cytokine and chemokine upregulation through the TLR2/NF-κB signaling pathway in RWPE-1 cells during bacterial infection and promotes an innate immune response.

Total triterpenoids from Ganoderma Lucidum suppresses prostate cancer cell growth by inducing growth arrest and apoptosis

In this study, one immortalized human normal prostatic epithelial cell line (BPH) and four human prostate cancer cell lines (LNCaP, 22Rv1, PC-3, and DU-145) were treated with Ganoderma Lucidum triterpenoids (GLT) at different doses and for different time periods. Cell viability, apoptosis, and cell cycle were analyzed using flow cytometry and chemical assays. Gene expression and binding to DNA were assessed using real-time PCR and Western blotting. It was found that GLT dose-dependently inhibited prostate cancer cell growth through induction of apoptosis and cell cycle arrest at G1 phase. GLT-induced apoptosis was due to activation of Caspases-9 and -3 and turning on the downstream apoptotic events. GLT-induced cell cycle arrest (mainly G1 arrest) was due to up-regulation of p21 expression at the early time and down-regulation of cyclin-dependent kinase 4 (CDK4) and E2F1 expression at the late time. These findings demonstrate that GLT suppresses prostate cancer cell growth by inducing growth arrest and apoptosis, which might suggest that GLT or Ganoderma Lucidum could be used as a potential therapeutic drug for prostate cancer.

Androgen Receptor-Mediated Growth Suppression of HPr-1AR and PC3-Lenti-AR Prostate Epithelial Cells.

The androgen receptor (AR) mediates the developmental, physiologic, and pathologic effects of androgens including 5α-dihydrotestosterone (DHT). However, the mechanisms whereby AR regulates growth suppression and differentiation of luminal epithelial cells in the prostate gland and proliferation of malignant versions of these cells are not well understood, though they are central to prostate development, homeostasis, and neoplasia. Here, we identify androgen-responsive genes that restrain cell cycle progression and proliferation of human prostate epithelial cell lines (HPr-1AR and PC3-Lenti-AR), and we investigate the mechanisms through which AR regulates their expression. DHT inhibited proliferation of HPr-1AR and PC3-Lenti-AR, and cell cycle analysis revealed a prolonged G1 interval. In the cell cycle, the G1/S-phase transition is initiated by the activity of cyclin D and cyclin-dependent kinase (CDK) complexes, which relieve growth suppression. In HPr-1AR, cyclin D1/2 and CDK4/6 mRNAs were androgen-repressed, whereas CDK inhibitor, CDKN1A, mRNA was androgen-induced. The regulation of these transcripts was AR-dependent, and involved multiple mechanisms. Similar AR-mediated down-regulation of CDK4/6 mRNAs and up-regulation of CDKN1A mRNA occurred in PC3-Lenti-AR. Further, CDK4/6 overexpression suppressed DHT-inhibited cell cycle progression and proliferation of HPr-1AR and PC3-Lenti-AR, whereas CDKN1A overexpression induced cell cycle arrest. We therefore propose that AR-mediated growth suppression of HPr-1AR involves cyclin D1 mRNA decay, transcriptional repression of cyclin D2 and CDK4/6, and transcriptional activation of CDKN1A, which serve to decrease CDK4/6 activity. AR-mediated inhibition of PC3-Lenti-AR proliferation occurs through a similar mechanism, albeit without down-regulation of cyclin D. Our findings provide insight into AR-mediated regulation of prostate epithelial cell proliferation.

Abstract 1652: Therapeutic targeting of ETS factor ERG for the treatment of prostate cancer

Abstract Prostate cancer (PCa) is one of the leading causes of cancer-related death in men worldwide. The common treatment option for recurring and advanced PCa focuses on inhibiting the androgen receptor (AR). Unfortunately, despite an initial response to this treatment, drug resistance occurs, and the cancer relapses to an incurable, castration-resistant form; thus, there is a pressing need for new therapeutics. Previous research has shown that in up to 50% of all prostate cancer cases, the cause of the disease may be attributed to a common genomic rearrangement, the fusion between TMPRSS2 and ERG (ETS-related gene). ERG is a transcription factor mainly involved in hematopoiesis regulation during embryonic development, and it is not normally expressed in prostate cells in adults. However, its fusion with the TMPRSS2 promoter puts ERG under the regulation of AR, and as a consequence, ERG is one of the most commonly overexpressed genes in PCa. ERG overexpression in prostate epithelium has been shown to induce transformation and promote epithelial-mesenchymal transition (EMT) that gives cancer cells enhanced migratory and invasive characteristics. Currently, there is no approved therapeutic targeting ERG or any other member of the ETS family. While targeting transcription factors has been challenging, our integrated research team is specialized in targeting protein-DNA interaction sites. Using our established computer-aided drug discovery pipeline, we have identified several small molecules that can bind to and inhibit ERG. A total of 133 candidate compounds, pre-selected from the in silico screening of millions of chemical structures, were tested using a luciferase-based transcriptional reporter assay across two cell lines: the TMPRSS2-ERG fusion positive VCaP cell line, and the human prostate epithelial cell line (PNT1B) engineered to constitutively express ERG. In addition to transcriptional inhibition, the most potent compounds inhibited migration of PNT1B-ERG cells as demonstrated by a Real-Time Cell Analyzer. Significantly, both compounds shifted the binding spectra in protein NMR assays, indicating their direct interactions with residues located in the DNA binding domain of the ERG protein. We anticipate that results from this project will lead to the development of new drugs that can be used alternatively or synergistically with current anti-AR therapy to benefit patients with the most deadly forms of prostate cancer. (Supported by a grant from Prostate Cancer Canada) Citation Format: Mani Roshan-Moniri, Michael Hsing, Miriam S. Butler, Desmond Lau, Peter Axerio-Cilies, Paul Yen, Ari Kim, Scott Lien, Marta Mroczek, Dennis Ma, Huifang Li, Yubin Guo, Fuqiang Ban, Fariba Ghaidi, Eric LeBlanc, Lawrence McIntosh, Michael Cox, Artem Cherkasov, Paul S. Rennie. Therapeutic targeting of ETS factor ERG for the treatment of prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1652. doi:10.1158/1538-7445.AM2015-1652

Down-regulated CFTR During Aging Contributes to Benign Prostatic Hyperplasia.

Benign prostatic hyperplasia (BPH) is a hyper-proliferative disease of the aging prostate; however, the exact mechanism underlying the development of BPH remains incompletely understood. The present study investigated the possible involvement of the cystic fibrosis transmembrane conductance regulator (CFTR), which has been previously shown to negatively regulate nuclear factor-κB (NF-κB)/cyclooxygenase 2 (COX2)/prostaglandin E2 (PGE2) pathway, in the pathogenesis of BPH. Our results showed decreasing CFTR and increasing COX2 expression in rat prostate tissues with aging. Furthermore, suppression of CFTR led to increased expression of COX2 and over-production of PGE2 in a normal human prostate epithelial cell line (PNT1A) with elevated NF-κB activity. PGE2 stimulated the proliferation of primary rat prostate stromal cells but not epithelial cells, with increased PCNA expression. In addition, the condition medium from PNT1A cells after inhibition or knockdown of CFTR promoted cell proliferation of prostate stromal cells which could be reversed by COX2 or NF-κB inhibitor. More importantly, the involvement of CFTR in BPH was further demonstrated by the down-regulation of CFTR and up-regulation of COX2/NF-κB in human BPH samples. The present results suggest that CFTR may be involved in regulating PGE2 production through its negative regulation on NF-κB/COX2 pathway in prostate epithelial cells, which consequently stimulates cell growth of prostate stromal cells. The overstimulation of prostate stromal cell proliferation by down-regulation of CFTR-enhanced PGE2 production and release during aging may contribute to the development of BPH.

Differential DNA methylation profile of key genes in malignant prostate epithelial cells transformed by inorganic arsenic or cadmium

Previous work shows altered methylation patterns in inorganic arsenic (iAs)- or cadmium (Cd)-transformed epithelial cells. Here, the methylation status near the transcriptional start site was assessed in the normal human prostate epithelial cell line (RWPE-1) that was malignantly transformed by 10μM Cd for 11weeks (CTPE) or 5μM iAs for 29weeks (CAsE-PE), at which time cells showed multiple markers of acquired cancer phenotype. Next generation sequencing of the transcriptome of CAsE-PE cells identified multiple dysregulated genes. Of the most highly dysregulated genes, five genes that can be relevant to the carcinogenic process (S100P, HYAL1, NTM, NES, ALDH1A1) were chosen for an in-depth analysis of the DNA methylation profile. DNA was isolated, bisulfite converted, and combined bisulfite restriction analysis was used to identify differentially methylated CpG sites, which was confirmed with bisulfite sequencing. Four of the five genes showed differential methylation in transformants relative to control cells that was inversely related to altered gene expression. Increased expression of HYAL1 (>25-fold) and S100P (>40-fold) in transformants was correlated with hypomethylation near the transcriptional start site. Decreased expression of NES (>15-fold) and NTM (>1000-fold) in transformants was correlated with hypermethylation near the transcriptional start site. ALDH1A1 expression was differentially expressed in transformed cells but was not differentially methylated relative to control. In conclusion, altered gene expression observed in Cd and iAs transformed cells may result from altered DNA methylation status.