bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A52: DNA damage responses in different cell types of nonproliferating human prostate tissue
Authors: af Hällstrsöm Taija M. , Taari Kimmo , Ruutu Mirja , Andersson Leif , Laiho Marikki , Jäämaa Sari , Sankila Anna , Rantanen Ville , Koistinen Hannu , Stenman Ulf-Håkan , Zhang Zhewei , Yang Zhiming , De Marzo Angelo M.
Published: May 2013

DNA damage response (DDR) pathways have been extensively studied in cancer cell lines and mouse models, but little is known about how DNA damage is recognized by different cell types in nonmalignant, slowly replicating human tissues. Here, we assess, using ex vivo cultures of human prostate tissue, DDR caused by cytotoxic drugs (camptothecin, doxorubicin, etoposide, and cisplatin) and ionizing radiation (IR) in the context of normal tissue architecture. Using specific markers for basal and luminal epithelial cells, we determine and quantify cell compartment-specific damage recognition. IR, doxorubicin, and etoposide induced the phosphorylation of H2A.X on Ser(139) (gH2AX) and DNA damage foci formation. Surprisingly, luminal epithelial cells lack the prominent gH2AX response after IR when compared with basal cells, although ATM phosphorylation on Ser(1981) and 53BP1 foci were clearly detectable in both cell types. The attenuated gH2AX response seems to result from low levels of total H2A.X in the luminal cells. Marked increase in p53, a downstream target of the activated ATM pathway, was detected only in response to camptothecin and doxorubicin. These findings emphasize the diversity of pathways activated by DNA damage in slowly replicating tissues and reveal an unexpected deviation in the prostate luminal compartment that may be relevant in prostate tumorigenesis. Detailed mapping of tissue and cell type differences in DDR will provide an outlook of relevant responses to therapeutic strategies.

Note: This abstract was not presented at the conference because the presenter was unable to attend.

Citation Format: Taija M. af Hällström, Kimmo Taari, Mirja Ruutu, Leif Andersson, Marikki Laiho, Sari Jäämaa, Anna Sankila, Ville Rantanen, Hannu Koistinen, Ulf-Håkan Stenman, Zhewei Zhang, Zhiming Yang, Angelo M. De Marzo. DNA damage responses in different cell types of nonproliferating human prostate tissue [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr A52.
Abstract A53: Effect of an ERβ agonist in the gerbil senile prostate: Novel treatment for age related disorders?
Authors: Rochel-Maia Sabrina S. , Taboga Sebastião R. , Warner Margaret , Gustafsson Jan-Åke
Published: May 2013

This study evaluated the effect of a selective estrogen receptor beta (ERβ) agonist in the prostate of the aging Mongolian gerbil. The gerbil is a rodent known for spontaneous development of prostatic lesions such as prostatic intraepithelial neoplasias (PIN), adenocarcinomas and micro invasive carcinomas as they become old. This representative feature makes the gerbil interesting for testing the role of novel targets to prevent or treat prostate cancer. ERβ is known to have anti-proliferative and pro-apoptotic effects in the prostate epithelium, and therefore is a potential target for treatment of prostatic disorders. ERβ agonist and vehicle pellets were implanted subcutaneously in 12-month-old male gerbils (n=5) and the ventral prostates were harvested after 3 and 7 consecutive days of treatment. The tissue was processed for light microscopy and stained for H&E for morphological analysis. Expression of the nuclear receptors AR, ERα and ERβ, as well as markers of proliferation and apoptosis were examined by immunohistochemistry. Anatomically, the prostates of gerbils treated with vehicle pellets were smaller and more compact than those treated for 3 days with the ERβ agonist. The change was due to increased volume of the ducts and return of the ductal epithelium to a single organized layer. Histologically, the slides stained with H&E showed a hyperplastic and inflamed epithelium with a dense stroma in the vehicle treated groups, as typical of senile gerbil prostates. However, the treatment with the ERβ agonist promoted a reorganization of the prostatic epithelium. Ducts became lined in single layer of cubic/columnar cells, with enlarged lumen, full of secretion. The hyperplastic phenotype had normalized. These effects were more prominent after 3 days than after 7 days and were confirmed by a decreased expression of the proliferation marker ki67. In addition, ERβ expression, which is usually very weak or undetectable in the prostate of 12-month-old gerbils, was fully recovered after 3 days of treatment while expression of ERα and AR remained the same, indicating the effects occurred via ERβ signaling exclusively. Upon 7 days of continuous exposure to the ERβ agonist, ERβ expression was down-regulated. Therefore, the results found so far are promising as they indicate the ERβ as a novel and effective target for the treatment of prostatic disorders. However, the route and regimen of drug delivery remains to be carefully worked out.

Citation Format: Sabrina S. Rochel-Maia, Sebastião R. Taboga, Margaret Warner, Jan-Åke Gustafsson. Effect of an ERβ agonist in the gerbil senile prostate: Novel treatment for age related disorders? [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr A53.
Abstract A9: Androgen-regulated miR-32 targets BTG2 and is overexpressed in castration-resistant prostate cancer
Authors: Jalava Sanni E. , Latonen Leena , Scaravilli Mauro , Waltering Kati K. , Seppälä Janne , Lähdesmäki Harri , Tammela Teuvo L.J. , Visakorpi Tapio
Published: May 2013

The androgen receptor (AR) signaling pathway is central to the emergence of castration-resistant prostate cancer (CRPC). We set out to identify androgen-regulated microRNAs (miRNAs) that may contribute to the development of CRPC. We found miR-32 to be an androgen regulated miRNA which is differentially expressed in CRPC compared to benign prostate hyperplasia (BPH) according to microarray analyses. qRT-PCR analyses confirmed that miR-32 expression increases in CRPC compared to BPH, and that in untreated prostate cancer (PC) miR-32 expression is higher in tumors of stage pT3 compared to pT2. Transfection of pre-miR-32 to prostate cancer cell line LNCaP provided a significant growth advantage to the cells, and miR-32 was further demonstrated to reduce apoptosis. To identify target genes for miR-32, an mRNA microarray analysis was performed with LNCaP cells transfected with pre-miR-32. In this assay, B cell translocation gene 2 (BTG2) was identified as a novel putative target for miR-32. BTG2 was reduced both at mRNA and protein level in the cells transfected with pre-miR-32, and BTG2 was confirmed to be a miR-32 target by 3′-UTR-luciferase assay. Furthermore, BTG2 was able to partially rescue the growth advantage of miR-32 in LNCaP cells. Immunostainings of prostate cancer patient material showed a statistically significant (p < 0.0001) reduction of BTG2 protein in CRPCs compared to PC. The lack of BTG2 staining was also associated (p=0.0021) with a short progression-free time in patients who underwent prostatectomy and inversely correlated to miR-32 expression levels. In conclusion, we find that miR-32 is an androgen-regulated miRNA targeting BTG2 and overexpressed in CRPC. Thus, miR-32 is a potential marker for aggressive disease and is a putative drug target in PC.

Citation Format: Sanni E. Jalava, Leena Latonen, Mauro Scaravilli, Kati K. Waltering, Janne Seppälä, Harri Lähdesmäki, Teuvo L.J. Tammela, Tapio Visakorpi. Androgen-regulated miR-32 targets BTG2 and is overexpressed in castrationresistant prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr A9.
Abstract B13: Cycloartane-3,24,25-triol: A cancer chemopreventive cycloartane inhibits MRCKα kinase and demonstrates anti prostate cancer activity in vitro
Authors: Lowe Henry I.C. , Toyang Ngeh J. , Bryant Joseph
Published: May 2013

In our study of the Jamaican ball moss (Tillandsia recurvata L.) for its prostate cancer chemotherapeutic properties, we have identified a number of cycloartane-type compounds from the chloroform crude extract. Cycloart-23-ene-3,25-diol was isolated and characterized from the extract. Attempts to run this compound in our kinase and antiproliferative assays were unsuccessful because of solubility problems. A search of the literature led us to Cycloartane-3,24,25-triol, a close analog of Cycloart-23-ene-3,25-diol. Cycloart-23-ene-3,25-diol differs from Cycloartane-3,24,25-triol only in the presence of a third hydroxyl group in this compound while Cycloart-23-ene-3,25-diol has only two hydroxyl groups. We isolated Cycloartane-3,24,25-triol from its source plant (Chrysanthemum morifolium) and screened it against a 451 kinase panel for inhibitory properties as well as for anti- prostate cancer cell proliferation activity using DU145 and PC-3 cell lines. Cycloartane-3,24,25-triol inhibited MRCKα (Myotonic dystrophy kinase-related Cdc42–binding kinase) kinase at a Kd of 0.26μM and showed IC50 values of 1.56±0.18μM and 2.04±0.28μM against DU145 and PC-3 prostate cancer cell lines respectively. MRCK kinases are now known to contribute to the process of tumor progression and metastasis through the control of the cytoskeleton which regulates tumor cell motility and invasion. In prostate cancer, the MRCKα kinase indirectly contributes to tumor progression by activating other kinases including the Lim kinase 1 (LIMK 1) which is over-expressed in prostate cancer and known to contribute to tumor cell invasion and migration leading to metastasis to other organs. This is the first report on the anti-prostate cancer activity and kinase inhibitory activity of Cycloartane-3,24,25-triol. The combined kinase and in vitro antiproliferation activity of Cycloartane-3,24,25-triol makes it a good candidate for further studies to determine its in vivo efficacy against prostate cancer.

Citation Format: Henry I.C. Lowe, Ngeh J. Toyang, Joseph Bryant. Cycloartane-3,24,25-triol: A cancer chemopreventive cycloartane inhibits MRCKα kinase and demonstrates anti prostate cancer activity in vitro [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B13.
Abstract B15: Development of a chimeric saporin peptide which targets human prostatecancer cells via monocyte delivery
Authors: Eskew Jeff , Troyer Deryl , Bossmann Stefan , Vielhauer George
Published: May 2013

Many attempts have been made to utilize plant and bacterial toxins to produce chimeric proteins that target and kill cancer cells; however, problems with specificity have slowed the progress of this potential therapy. We hypothesize that the specificity of these chimeric cytotoxic peptides can be improved by incorporating two layers of targeting. This will be accomplished by using the inherent tumor targeting properties of monocytes as well as engineering them to secrete a chimeric saporin peptide possessing a targeting element that is highly specific to human prostate cancer cells. Saporin is a small protein produced by soapwort that is a member of the ribosome inactivating protein (RIP) family. This family consists of some of the most potent toxins known to man, including ricin and abrin. RIPs act by gaining entry to the cell and then catalytically inactivating the ribosome. Ricin and abrin are very potent toxins because they contain two chains, a beta chain that gains entrance to the cell and an alpha chain that catalytically inactivates the ribosome. Saporin, unlike ricin or abrin, contains only the alpha chain; thus cell entry is prevented and making it, in theory, harmless unless it is attached to something that causes the cell to internalize it. In order to identify a highly specific and internalizable peptide that could be fused to a saporin molecule we screened a random 12-mer peptide bacteriophage library against the human prostate cancer cell line PC3. After several rounds of in-vitro and in-vivo biopanning we have isolated candidate peptides that appear specific and rapidly internalizable in PC3 cells. Using these peptides as targeting elements we propose to create a chimeric protein consisting of a signal peptide for secretion, a targeting peptide, and the cytotoxic saporin. This chimeric protein will be expressed in primary monocytes using a lentiviral system. Our preliminary data show that this fusion protein demonstrates profound cytotoxicity in PC3 cells within 72 hours. We have also developed an efficient orthotopic and metastatic human prostate cancer model in mice and have preliminary data showing monocyte recruitment to metastatic nodes. In conclusion, peptides that specifically target metastatic PC3 cells have been identified, in vivo, and have been linked to toxins that demonstrate potent cytotoxicity in vitro. Future studies will be to test the selective targeting of these toxic chimeric proteins, in vivo, utilizing primary and metastatic orthotopic tumor models of human prostate cancer in tumor efficacy studies.

Citation Format: Jeff Eskew, Deryl Troyer, Stefan Bossmann, George Vielhauer. Development of a chimeric saporin peptide which targets human prostatecancer cells via monocyte delivery [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B15.
Abstract B19: Induction of apoptosis and antitumor activity of the AKT inhibitor AZD5363 is enhanced by combination with hormonal therapies in preclinical models of prostate cancer
Authors: Crafter Claire , Davies Barry R. , Thomas Christian , Lamoureux Francois , Greenwood Hannah , Garcia-Martinez Juan M. , Mooney Lorraine , Cosulich Sabina , Gleave Martin , Zoubeidi Amina
Published: May 2013

Activation of AKT by mechanisms including loss of the tumor suppressors PTEN and INPP4B is very common in prostate cancer, and has been correlated with poor prognosis and progression to androgen independent disease. Recently, a reciprocal feedback mechanism has been shown to occur between the androgen and AKT signalling axes in prostate cancer models. AZD5363 monotherapy induced apoptosis and inhibited growth of PTEN null, AR+ prostate cancer cell lines including LNCaP, C4-2 and a flutamide resistant variant of PC346C (GI50 10 – 100 nM), and showed moderate anti-proliferative activity in AR amplified, PTEN wild type VCaP cells (GI50 ∼ 1 μM). The PTEN wild type, AR negative DU-145, BPH1 and RWPE1 cell lines were relatively resistant. Monotherapy AZD5363 also caused dosedependent growth inhibition of the PTEN null, AR+ HID28 prostate cancer explant model in vivo. Treatment with AZD5363 increased expression of a panel of androgen regulated genes in LNCaP cells, whereas the same panel of genes was down-regulated when AZD5363 was combined with the novel anti-androgen MDV-3100. Combination of AZD5363 with MDV-3100 resulted in greater inhibition of growth and induction of apoptosis in vitro than monotherapy treatment with these agents, indicating a synergistic interaction. Moreover, combination of AZD5363 and bicalutamide resulted in greater efficacy than AZD5363 monotherapy in LNCaP xenografts in vivo. The data show that whilst AZD5363 has considerable monotherapy activity in AR+/PTEN null prostate cancer models, the combination with anti-androgens merits further evaluation as a possible means to achieve greater anti-tumor activity. AZD5363 is currently in Phase 1 clinical trials.

Citation Format: Claire Crafter, Barry R. Davies, Christian Thomas, Francois Lamoureux, Hannah Greenwood, Juan M. Garcia-Martinez, Lorraine Mooney, Sabina Cosulich, Martin Gleave, Amina Zoubeidi. Induction of apoptosis and antitumor activity of the AKT inhibitor AZD5363 is enhanced by combination with hormonal therapies in preclinical models of prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B19.
Abstract B2: Delineating the metabolic pathway to DHT in castration-resistant prostate cancer
Authors: Chang Kai-Hsiung , Li Amy , Sharifi Nima
Published: May 2013

After an initial response to androgen deprivation therapy (ADT) by depletion of gonadal testosterone, re-fueling androgen receptor in metastatic tumors is a critical mechanism required to drive castration resistant prostate cancer (CRPC) progression. Testosterone (T) is generally regarded as an obligate precursor for dihydrotestosterone (DHT) synthesis from adrenal precursors in CRPC and the up-regulation of steroid-5α-reductase isoenzyme-1 (SRD5A1) over SRD5A2 in CRPC is thought to convert T to DHT. Our recent findings demonstrated that an alternative pathway, namely androstenedione (AD) → 5α-androstanedione (5α-dione) → DHT, is dominant in CRPC. In this alternative pathway, AD prevails over T as a preferred substrate for 5α-reduction in CPRC. In particular, SRD5A1-mediated conversion of AD to 5α-dione is a prerequisite for converting adrenal steroids to DHT and for CRPC growth in mouse xenograft models. How 5α-dione is processed in CRPC is unknown. There are two possible routes from 5α-dione to DHT in the alternative pathway. The first route is direct 17-ketoreduction of 5α-dione by 17β-hydroxysteroid dehydrogenase-3 (17βHSD3) or 17βHSD5 (also known as aldo-keto reductase family 1, member C3, AKR1C3), both of which are up-regulated in CRPC progression. The second route is through a circuitous pathway, which requires 3-keto-reduction to 3α-hydroxyl, prior to 17-keto-reduction, namely 5α-dione → androsterone (AST) → 5α-androstane- 3α,17β-diol (Adiol) → DHT. Here, we show that ectopic expression of HSD17B5 in 293T cells efficiently converts 5α-dione to DHT, whereas AKR1C2 robustly catalyzes 5α-dione to AST and ultimately to DHT. This suggests that metabolism of 5α-dione may be determined by the relative expression and enzymatic activities of AKR1C3 and AKR1C2. These findings offer insights into the synthesis of DHT in CRPC and for the development of new therapeutic strategies.

Citation Format: Kai-Hsiung Chang, Amy Li, Nima Sharifi. Delineating the metabolic pathway to DHT in castration-resistant prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B2.
Abstract B23: Identification of TMPRSS2:ERG-dependent regulators of AR function and differentiation status in prostate cancer
Authors: Mounir Zineb , Pagliarini Raymond , Lin Fallon , Schirle Markus , Klekota Justin , Feng Yan , Hartung Anke , Jaffe Aron , Buchwalter Gilles , Brown Myles
Published: May 2013

Oncogenic translocations involve the chromosomal rearrangement and fusion of two genes, which can result in either deregulated gene expression or the generation of a chimeric protein with unique oncogenic properties. Among these, fusions of the androgen-activated gene TMPRSS2 to the ETS transcription factor ERG occur in 40%–80% of prostate cancers and result in elevated expression of the ERG gene. Although a number of studies demonstrate the importance of ERG as a driver for prostate cancer development, the molecular mechanisms of ERG-mediated oncogenesis remain elusive. A deeper understanding of how ERG disrupts normal prostate biology may ultimately assist in the development of therapies that selectively target TMPRSS2:ERG -positive prostate cancer. We provide evidence that a primary role of ERG in prostate cancer is to specifically disrupt the normal regulation of androgen receptor (AR) signaling, resulting in a selective attenuation of AR's ability to promote prostate epithelial cell differentiation. We are testing the hypothesis that ERG proteins require recruitment of additional cofactors to mediate these AR regulatory functions, and that some of these protein partners may be valid therapeutic targets. Towards this end, we are working to elucidate the full network of ERG-interacting proteins, and validating which of these interactors are necessary and/or sufficient for the oncogenic and de-differentiation functions of ERG in prostate cancer.

Citation Format: Zineb Mounir, Raymond Pagliarini, Fallon Lin, Markus Schirle, Justin Klekota, Yan Feng, Anke Hartung, Aron Jaffe, Gilles Buchwalter, Myles Brown. Identification of TMPRSS2:ERG-dependent regulators of AR function and differentiation status in prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B23.
Abstract B38: The histone deacetylase inhibitor LBH589 combined with radiation is an effective regimen for prostate cancer
Authors: Weiwei Xiao , Peter Graham , Carl Power , Qihan Dong , Paul Cozzi , John Kearsley , Yong Li
Published: May 2013

Background: Radiotherapy (RT) is one of the major curative treatment options for patients with localized prostate cancer (CaP). However radiation resistance is still the main problem for the current CaP therapy. The use of small molecular inhibitors, combined with RT provides a valuable alternative approach for cancer therapy.

Aims: The purpose of the study was to investigate the in vitro effect of LBH589 [a pan- Histone deacetylase inhibitor (HDACi)] alone and in combination with RT on the growth and survival of CaP cell lines and the possible mechanisms of radiosensitization effect.

Methods: The effect of LBH589 alone or in combination with RT on two CaP cell lines (PC-3 and LNCaP) and a normal prostatic epithelial cell line (REWP-1) was studied by MTT and clonogenic assays, cell cycle analysis, immunoblot of apoptosis-related and cell check point proteins, and DNA double strand break (DSB) repair marker. The immunofluorescence staining was used to further confirm DSB expression in treated CaP cells.

Results: LBH589 inhibited both CaP cell lines and normal prostatic epithelial cell proliferation in a time- and dose-dependent manner. Low-dose of LBH589 (IC20) combined with RT greatly improved efficiency of cell killing in CaP cells. Compared to RT alone, the combination treatment of LDH589 and RT induced more apoptosis and led to a steady increase of sub-G1 population and abolishment of RT-induced G2/M arrest. In addition, increase and persistent DSB, less activation of DNA-PKcs, Ku70, Ku80 and a panel of cell cycle related proteins were also observed in combination treatment.

Conclusions: These results suggest that LBH589 is a potential agent to increase radiosensitivity of human CaP cells. LBH589 used either alone, or in combination with RT is an attractive strategy for treating human CaP.

Grant sponsor: National Health & Medical Research Council (NH&MRC) Career Development Fellowship, St. George Hospital Cancer Research Trust Fund and China Scholarship Council (CSC).

Citation Format: Xiao Weiwei, Graham Peter, Power Carl, Dong Qihan, Cozzi Paul, Kearsley John, Li Yong. The histone deacetylase inhibitor LBH589 combined with radiation is an effective regimen for prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B38.
Abstract B4: Elevated expression of c-FLIP in castrate-resistant prostate cancer antagonizes response to androgen receptor-targeted therapy
Authors: McCourt Clare , Maxwell Pamela , Mazzucchelli Roberta , Salto-Tellez Manuel , O'Sullivan Joe , Montironi Rodolfo , Scarpelli Marina , Longley Daniel , Waugh David
Published: May 2013

Cellular Fas-associated death domain (FADD)-like interleukin 1β-converting enzyme (FLICE) inhibitory protein (c-FLIP) is a key inhibitor of caspase 8 (FLICE)-promoted apoptosis. We have previously shown c-FLIP to be a transcriptional target of the androgen receptor (AR) and NF-κB. Accordingly, we proposed that cells with elevated expression of c-FLIP may remain viable and withstand androgen-deprivation. Expression of c-FLIP was assessed in prostatectomy tissue while in vitro experiments were performed to determine its importance in regulating response to the androgen receptor (AR)-targeted therapeutic bicalutamide. c-FLIP expression was increased in pre-malignant prostatic intra-epithelial neoplasia (PIN) (P<0.001) and each of Gleason 3 and Gleason 4 prostate cancer (CaP) tissue (P<0.001) relative to normal prostate epithelium. Maximal expression of c-FLIP was detected in castrate-resistant prostate cancer (CRPC) (P<0.001 relative to Gleason 3/4 cancer. In vitro, siRNA-mediated silencing of c-FLIP in 22Rv1 and LNCaP cells induced spontaneous apoptosis and increased their response to bicalutamide, determined by flow cytometry, PARP cleavage and caspase activity assays. Two histone deacetylase inhibitors (HDACi), droxinostat and SAHA, were also shown to down-regulate c-FLIP expression, resulting in caspase-8 and caspase-3/7 mediated apoptosis. HDACi also potentiated the sensitivity of 22Rv1 cells to bicalutamide, while maximal apoptosis induction in LNCaP cells was not changed in the presence of bicalutamide. The combination of SAHA and bicalutamide promoted cell-specific inhibition of the AR or NF-κB signaling pathways consistent with decreased transcription of c-FLIP in these cells. Conversely, the elevated expression of c-FLIP and Bcl-2 was consistent with the insensitivity of the castrate-resistant VCaP cell line to SAHA in vitro, and the sub-optimal performance of this class of agents in castrate-resistant patients. Therefore, HDACi may prove more effective in enhancing androgen-deprivation therapy (ADT) in early-stage disease. Moreover, c-FLIP expression may serve as a predictive biomarker for androgen-deprivation strategies including bicalutamide.

Citation Format: Clare McCourt, Pamela Maxwell, Roberta Mazzucchelli, Manuel Salto-Tellez, Joe O'Sullivan, Rodolfo Montironi, Marina Scarpelli, Daniel Longley, David Waugh. Elevated expression of c-FLIP in castrate-resistant prostate cancer antagonizes response to androgen receptor-targeted therapy [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B4.
Abstract B41: Urinary EN2 levels predict tumor volume in men undergoing radical prostatectomy for prostate cancer
Authors: Pandha Hardev , Sorensen Karina , Orntoft Torben Falck , Langley Stephen , Hoyer Soren , Borre Michael , Morgan Richard
Published: May 2013

Total tumor volume has been proposed as a guide to managing prostate cancer by immediate treatment versus active surveillance. We evaluated the relationship between levels of a recently described prostate cancer biomarker EN2 (Engrailed-2) in urine and cancer volume in men who had undergone radical prostatectomy for prostate cancer. Archived patient samples from the Aarhus Prostate Cancer Project, Denmark, were assessed. Pre-treatment mid stream urines, without preceding prostatic massage, were collected and stored at −80°C. Urinary EN2 levels were measured by a recently published Enzyme-linked Immunosorbent Assay (ELISA). 88 of the whole cohort of 125 men (70%) were positive for EN2 in their urine (>42.5 μ/L); 38/58 (65%) of men where cancer volume data was available. No statistical relationship was found between urinary EN2 levels and serum PSA. PSA levels did not correlate with tumor stage, combined Gleason grade, total prostatic weight or cancer volume. We found a strong statistical relationship between urinary EN2 and prostate cancer volume by linear regression (p=0.0058). Furthermore, higher EN2 levels correlated with tumor stage T1 versus T2 (p=0.0272). Pre-surgical urinary EN2 levels were associated with increasing tumor stage and closely reflected the volume of cancer in prostatectomy specimens. Given the ease of collection (no prostatic massage required) and the simplicity, low cost and robustness of the assay, EN2 may become a useful biomarker in not only identifying which patients have prostate cancer but may also facilitate risk stratification by indicating the burden of tumor volume.

Citation Format: Hardev Pandha, Karina Sorensen, Torben Falck Orntoft, Stephen Langley, Soren Hoyer, Michael Borre, Richard Morgan. Urinary EN2 levels predict tumor volume in men undergoing radical prostatectomy for prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B41.
Abstract B53: MiR-1 inhibits EMT via Slug-dependent and tumorigenesis via Slug-independent mechanisms
Authors: Liu Yen-Nien , Yin Juan Juan , Abou-Kheir Wassim , Hynes Paul , Casey Orla , Martin Philip , Kathleen Kelly
Published: May 2013

EMT is a developmental program of signaling pathways that determine commitment to epithelial and mesenchymal phenotypes. In the prostate, EMT processes have been implicated in benign prostatic hyperplasia and prostate cancer progression. In a model of Pten and TP53 null prostate adenocarcinoma that progresses via TGFβ-induced EMT, mesenchymal transformation is characterized by plasticity leading to various mesenchymal lineages and the production of bone. Here we show that SLUG is the dominant regulator of mesenchymal differentiation. As microRNAs are pleiotropic regulators of differentiation and tumorigenesis, we evaluated miR expression associated with tumorigenesis and EMT. Mir-1 and mir-200 were reduced with progression of prostate adenocarcinoma, and we identify Slug as one of the phylogenetically-conserved targets of these miRs. We demonstrate that SLUG is a direct repressor of miR-1 and miR-200 transcription. Thus, SLUG and miR-1/miR-200 act in a self-reinforcing regulatory loop leading to amplification of EMT. Depletion of Slug inhibited EMT during tumorigenesis, while forced expression of miR-1 or miR-200 inhibited both EMT and tumorigenesis in human and mouse model systems. Various miR targets were analyzed, and our findings suggest that miR-1 has roles in regulating EMT and mesenchymal differentiation through Slug and functions in tumor-suppressive programs by regulating additional targets.

Citation Format: Yen-Nien Liu, Juan Juan Yin, Wassim Abou-Kheir, Paul Hynes, Orla Casey, Philip Martin, Kelly Kathleen. MiR-1 inhibits EMT via Slugdependent and tumorigenesis via Slug-independent mechanisms [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B53.
Abstract B55: Mutation of PlexinB1 in prostate cancer
Authors: Williamson Magali , Masters John
Published: May 2013

Semaphorins are secreted proteins that have a role in chemotaxis and are implicated in cancer. Plexins are membrane-bound receptors for semaphorins. We have found a high frequency of mutations in the plexinB1 gene and overexpression of the protein in prostate tumours (Wong et al., 2007; PNAS 104: 19040-5) indicating a role for plexinB1 in the pathogenesis of prostate cancer. The mutations of plexinB1 found in prostate tumours are functionally significant, increasing cell motility, invasive capacity, adhesion and inhibiting cell collapse. The mutations affect signalling pathways downstream of plexinB1, inhibiting Rac, Rnd, and R-Ras binding to plexinB1 and R-RasGAP activity. The mutations have the net effect of increasing cell motility by the loss of inhibitory pathways.

We have now found that knockdown of endogenous plexinB1 in the prostate cancer cell line LNCaP inhibits anchorage-independent growth, while stimulation with semaphorin4D, the ligand for plexinB1, increases the migration and invasive capacity of LNCaP cells. These effects are reversed by expression of shRNA to plexinB1. Stimulation with semaphorin4D also results in ErbB2 and Akt activation. The opposite effects occur in the prostate cancer cell line PC3 in response to semaphorin4D. The opposite response of LNCaP and PC3 may be due to high levels of ErbB2 or c-Met expressed by the two cell lines respectively. These findings provide evidence for a subset of prostate tumours in which plexinB1 acts as a tumour-enhancing gene by activating ErbB2 and in which mutation of plexinB1 results in loss of cancer-inhibitory pathways.

Citation Format: Magali Williamson, John Masters. Mutation of PlexinB1 in prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B55.
Abstract B60: Prostate-derived factor/macrophage inhibitory cytokine-1/nonsteroidal anti-inflammatory drug activated gene: A mediator of prostatic inflammation
Authors: Whitson Ramon J. , Genova Erin , Torkko Kathleen , Rosa Francisco G. La , Kelly Julie , Wilson Storey , Lambert James R. , Lucia Marshall Scott
Published: May 2013

Prostatic inflammation is recognized as a potential initiating and potentiating factor in the development of prostate cancer. Prostate derived factor (PDF), also known as macrophage inhibitory cytokine-1 (MIC-1) and nonsteroidal anti-inflammatory drug activated gene (NAG-1), was first cloned in a screen for genes involved in macrophage activation and as a gene induced by nonsteroidal anti-inflammatory drugs in colorectal carcinoma cells. These findings suggested that PDF may play a role in inflammatory processes. Previously, we identified an inverse relationship between PDF staining and inflammation severity using immunohistochemical (IHC) analysis in human prostatectomy samples suggesting a role for PDF in prostatic inflammation. Here, we extended these findings by examining the histologic compartment and inflammatory cell types that are potentially affected by PDF in the prostate. We found that a significant inverse relationship exists between PDF staining and CD3+ (T cells), CD4+ (T helper cells), CD8+ (cytotoxic T cells), and CD68+ (macrophages) cells in both the epithelial and periglandular compartments of the prostate. Linear correlation analysis using PDF and inflammatory cell marker staining showed moderate negative correlations with r values ranging from −0.47 to −0.52 and −0.43 to -0.46 in the epithelial and periglandular regions respectively (p < 0.006). To identify a potential mechanism for the role of PDF during inflammation, we studied the effect of PDF on NF-kappaB activity in PC3 prostate cancer cells. Increased expression of PDF was accompanied by a decrease in NF-kappaB minimal promoter activation. In addition, increased PDF expression resulted in decreased activation of the NF-kappaB-regulated promoters for COX2 and IL8. These findings suggest that PDF may suppress prostatic inflammatory responses by inhibiting expression of key genes mediating inflammatory responses in human prostate.

Citation Format: Ramon J. Whitson, Erin Genova, Kathleen Torkko, Francisco G. La Rosa, Julie Kelly, Storey Wilson, James R. Lambert, Marshall Scott Lucia. Prostate-derived factor/macrophage inhibitory cytokine-1/nonsteroidal anti-inflammatory drug activated gene: A mediator of prostatic inflammation [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B60.
Abstract B8: Hypoxia enhances androgen receptor activation in prostate cancer cells in response to low levels of androgens
Authors: Rudolfsson Stina , Toolanen Erik , Bergh Anders
Published: May 2013

Hypoxia is an important microenvironmental factor influencing tumor progression and treatment response. The understanding how hypoxia is regulating the behavior of cancer cells has to be further explored. The androgen receptor (AR) acts as a transcriptional factor controlling development or progression of prostate cancer (PC). Androgen ablation by castration is the common therapy for advanced PC but eventually most of the tumors relapse to a castration-resistant state and grow even in a low androgen environment. The remaining androgens that are still present after therapy may continue to promote AR activation. The most potent AR ligands, testosterone (T) and dihydrotestosterone (DHT), can be synthesized locally in the prostate from adrenal androgens and castration-resistant PC and bone metastases are shown to express increased levels of enzymes responsible for androgen metabolism (Akr1c3 one of several enzymes).

As castration results in a transient tissue hypoxia and solid tumors are generally hypoxic prior to treatment we investigated how hypoxia affects AR activation in androgen-sensitive prostate cancer CWR22Pc cells additional to steroidal treatment. Hypoxia upregulated the mRNA expression of the androgen-responsive NKX3.1 and prostate specific antigen (PSA), and facilitated translocation of AR to the nucleus in the presence of 0,01 nM DHT or 100 nM androstenediol. The androstenediol activation of AR simultaneously increased mRNA expression of the androgen converting enzyme Akr1c3 possibly resulting in metabolism of androstenediol to T or DHT.

This study shows that the AR can be hypersensitized to low levels of androgens in PC cells grown in a hypoxic milieu as in solid tumors and after castration. A consequence of exposure of PC cells to hypoxia is a possible increase in local biosynthesis of T and DHT from adrenal androgens or a direct ligand binding effect by adrenal androgen to activate the AR.

Citation Format: Stina Rudolfsson, Erik Toolanen, Anders Bergh. Hypoxia enhances androgen receptor activation in prostate cancer cells in response to low levels of androgens [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B8.
Abstract C15: RB status alters the response of prostate cancer to ionizing radiation
Authors: Den Robert B. , Ciment Steve , Sharma Ankur , Mellert Hestia , McMahon Steve , Dicker Adam P. , Knudsen Karen E.
Published: May 2013

Background: Prostate cancer is the most frequently diagnosed malignancy and the second leading cause of cancer death in U.S. men. We have previously shown that RB loss results in a castrate resistant phenotype and impacts on the sensitivity of prostate cancer to different chemotherapies. However the consequences of RB status with regard to radiation response are unknown. We hypothesized that RB loss would downregulate the G1-S cell cycle checkpoint arrest normally induced by irradiation, inhibit DNA repair, and subsequently sensitize cells to ionizing radiation.

Methods: Experimental work was performed with multiple isogenic prostate cancer cell lines (hormone sensitive: LNCaP and LAP-C4 cells and hormone resistant C42, 22Rv1 cells; stable knockdown of RB using shRNA). Gamma H2AX and 53BP1 assays were used to quantitate DNA damage; PARP cleavage and Caspase 3 were used to quantitate apoptosis; FACS analysis with BrdU was used to assess the cell cycle; beta galactosidase was used to assess senescence. Cell survival was measured using the clonogenic cell survival assay. In vivo work was performed in nude mice with tumor xenografts.

Results: We observed that loss of RB increased the radioresponsiveness in both transient and clonogenic cell survival assays in both hormone sensitive and castrate resistant cell lines (p<0.05). Cell death was not mediated through increased apoptosis or alterations in cell cycle. However, loss of RB effected DNA damage repair as well as cellular senescence. In vivo xenografts of the RB deficient tumors exhibited diminished tumor mass, lower PSA kinetics and decreased tumor growth after treatment with single fraction of ionizing radiation in comparison to RB intact tumors (p<0.05).

Conclusions: Loss of RB results in a differential response to ionizing radiation. Isogenic cells with RB knockdown are more sensitive to DNA damage and result in reduced cell survival. The underlying mechanism appears to be related to DNA damage repair and cellular senescence.

Citation Format: Robert B. Den, Steve Ciment, Ankur Sharma, Hestia Mellert, Steve McMahon, Adam P. Dicker, Karen E. Knudsen. RB status alters the response of prostate cancer to ionizing radiation [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr C15.
Abstract C27: Whole-exome sequencing identifies potential therapeutic targets for castration-resistant prostate cancer
Authors: Menon Roopika , Deng Mario , Boehm Diana , Fend Falko , Boehm Detlef , Biskup Saskia , Perner Sven
Published: May 2013

Aim: Castration resistant prostate cancer (CR-PCa) is the most aggresive form of prostate cancer (PCa) having a poor prognosis, and is a significant therapeutic challenge. The key to the development of novel therapeutic targets for CR-PCa is to decipher the molecular alterations underlying this lethal disease. The aim of our study was to perform whole exome sequencing and gene copy number analysis on 5 CR-PCa/normal paired formalin fixed paraffin embedded (FFPE) samples using the SOLiD4 next generation sequencing platform.

Methods: Genomic DNA was extracted from 5 CR-PCa/normal paired FFPE samples. The DNA was subjected to targeted exon capture using the Agilent Sure Select kit. The captured DNA was sequenced using the SOLiD4 next generation sequencing platform. The sequencing output was mapped, sorted, filtered and annotated using well-known human genome databases. The results were further analyzed for SNPs and copy number variations. A set of amplified/deleted genes were validated using fluorescence in-situ hybridization (FISH) assays with a PCa progression cohort. The cohort consisted of 138 cases for localized cancer, 105 patients with primary PCa and corresponding LN metastasis, and 39 samples for castration resistant tumors.

Results: Whole exome sequencing analysis identified focal regions of deletion, which included well-known tumor suppressors such as NKX3.1 and PTEN. Focal regions of amplification included well-known genes such as CMYC and AR that are known to play a role in PCa. Furthermore, we identified several amplified genes as druggable targets e.g. HDAC6, NTRK1, PLD1, SPHK1, and SIRT7. NTRK1 is a kinase that plays an active role in cell proliferation. HDAC6, PLD1, SPHK1 and SIRT7 regulate numerous complex cellular processes including signal transduction, transcription and apoptosis.

Conclusions: This is the first study to use whole exome sequencing approaches on FFPE CR-PCa material to identity novel therapeutic targets. Validation studies would further shed light into the biological understanding of the disease and its plausible treatment options.

Citation Format: Roopika Menon, Mario Deng, Diana Boehm, Falko Fend, Detlef Boehm, Saskia Biskup, Sven Perner. Whole-exome sequencing identifies potential therapeutic targets for castration-resistant prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr C27.
Abstract C29: Prostate cancer detection and localization with diffusion-weighted imaging and 1H-MR spectroscopy
Authors: Singh Akash
Published: May 2013

Diffusion-weighted imaging (DWI) of the human with 1.5T MRI gives the insight of Prostate Cancer Tissue details. DWI is now used also for other Liver, Kidney, and Heart Imaging than the brain, and especially focused on detection of Cancer Tissues in prostate.1H-MR spectroscopy technique is used to detect and localize prostate cancer. One difficult sight of 1.5T prostate spectroscopy is the use of a special endorectal coil, it is a thin wire covered with a latex balloon and inserted inside the tail end of the large bowel which is rectum. We detected and identified the prostate cancer by DWI and 3D 1H-MRS with a external phase arrayed multi-coils, this is optimal tumor invasion through bowel wall and adjacent organs.

Note: This abstract was not presented at the conference because the presenter was unable to attend.

Citation Format: Akash Singh. Prostate cancer detection and localization with diffusion-weighted imaging and 1H-MR spectroscopy [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr C29.
Abstract C38: Whole-genome sequencing of paired androgen-dependent and -independent prostate cancer cell lines: Potential role of novel targets in PI3K and Notch signaling pathways in resistance to hormonal therapy
Authors: Dalgliesh Gillian L. , Hartley Joanne L. , O'Donnell Cary H. , Bradford James R. , McKendrick Iain , Davies Barry R.
Published: May 2013

The growth of the majority of prostate tumors is driven by androgens signaling through the androgen receptor. Most patients initially respond to androgen deprivation therapies such as LHRH analogues and anti-androgens like bicalutamide, but after a varying duration of treatment, patients generally develop resistance to these therapies and their tumor progresses to an androgen independent state. Molecular mechanisms that drive androgen independent disease include mutation and amplification of androgen receptor (AR), androgen-independent activation of AR, and AR-independent mechanisms. The aim of this project was to sequence the entire genome of pairs of cell lines, modeling the progression to androgen independent disease, to increase our understanding of these mechanisms and identify new therapeutic targets. Four ‘parental’ prostate cancer cell lines, all of which are sensitive to hormone deprivation, and an androgen independent derivative of each line, derived either by culturing in bicalutamide or growing in the absence of androgens, were subjected to whole genome sequencing. Genomic variants present in the androgen independent but not the parental lines, presumed to be acquired during the progression to androgen independence, were then identified. To find any commonality between the four different pairings, the derived variants were then mapped to functional biological pathways and their likely impact on protein function predicted. Interestingly, derived mutations in the PI3K and Notch signaling pathways were identified in multiple cell lines. In addition to the analysis of derived mutations, baseline characterization of genomic rearrangements and copy number changes in cell lines highlighted variability in the patterns and prevalence of these events as well as uncovering aberrations in genes known to impact prostate cancer development (PTEN, AR, TMPRSS2 rearrangement). This extensive genome sequencing effort has yielded a deeper understanding of potential pathways and molecular events that occur during the acquisition of resistance to anti-androgen therapy, using in vitro models of prostate cancer. These candidates now require validation in tissue samples from prostate cancer patients and functional assays.

Citation Format: Gillian L. Dalgliesh, Joanne L. Hartley, Cary H. O'Donnell, James R. Bradford, Iain McKendrick, Barry R. Davies. Whole-genome sequencing of paired androgen-dependent and -independent prostate cancer cell lines: Potential role of novel targets in PI3K and Notch signaling pathways in resistance to hormonal therapy [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr C38.