Treatment Of PCa Research Articles

Abstract B06: Repositioning HIV-based small molecule inhibitors of the stress oncoprotein LEDGF/p75 to overcome prostate cancer resistance to taxane chemotherapy

Abstract Prostate cancer (PCa) is the most frequently diagnosed cancer and the second leading cause of cancer-related deaths in men. In addition, African American (AA) men have a higher incidence of PCa with more aggressive tumors and increased mortality compared to other ethnic groups. The rise in the U.S. aging male population and the health disparities associated with this cancer type, are expected to make PCa a formidable public health and fiscal challenge in the next few decades. PCa mortality is driven by the ability of advanced prostate tumors to metastasize to vital organs and develop resistance against established anti-androgen therapies and chemotherapeutic drugs. Despite recent developments in the treatment of advanced PCa, the high mortality and the racial disparities associated with this disease still persist. For this reason, there is still an urgent medical need for innovative therapeutic approaches to reduce the burden of PCa mortality and its associated disparities. Our laboratory is at the forefront of research on the contribution of the lens epithelium-derived growth factor of 75 kD (LEDGF/p75) to PCa cancer aggressiveness. This protein is a stress response transcription coactivator that is overexpressed in PCa cells and clinical tumors, transcriptionally upregulates stress survival proteins in cancer cells, and promotes resistance to Docetaxel (DTX), the first line chemotherapeutic drug used to treat advanced PCa. Interestingly, LEDGF/p75 also plays a critical role in facilitating the integration of human immunodeficiency virus 1 (HIV-1) into active host chromatin by interacting with the HIV-integrase (HIV-IN). This biological function has made LEDGF/p75 an attractive druggable target, and for this purpose a series of novel and potent small molecule inhibitors (SMI) have been designed and studied to disrupt the interaction between HIV-IN and the C-terminal region of LEDGF/p75, which we previously implicated in its pro-survival activity. We hypothesize that repositioning these SMI for PCa treatment in combination with DTX is an innovative approach to re-sensitize DTX resistant PCa cells to chemotherapy. We observed that PC3 and DU145 cells selected for DTX resistance expressed high levels of LEDGF/p75, and were also selectively resistant to the taxanes Cabazitaxel (CTX) and Paclitaxel (PTX), but not to the classical apoptosis inducer TRAIL. Immunoblotting analysis indicated that LEDGF/p75 is cleaved and inactivated by caspases during TRAIL-induced cell death, whereas the protein remained intact in taxane treated cells. RNA interference-mediated knockdown of LEDGF/p75 in DTX-resistant cell lines sensitized them to taxane therapy. This provided proof of principle that functional inactivation of LEDGF/p75 could restore chemosensitivity. We then screened a panel of over 100 HIV-based candidate LEDGF/p75 SMI for their cytotoxicity against DTX-resistant and -sensitive PCa cells, in the presence and absence of DTX. These experiments yielded a number of inhibitors that re-sensitized the resistant cells to taxane treatment. We are currently expanding these studies to a panel of racially diverse PCa cell lines to determine the efficacy of this approach in multiple PCa cell types. Taken together, our results suggest that LEDGF/p75 is a druggable target that could potentially be functionally inactivated by repositioned HIV-based inhibitors in combination with established chemotherapeutic regimens to circumvent PCa chemoresistance and reduce the mortality disparities associated with the aggressive form of this disease. Citation Format: Leslimar Rios-Colon, Tino Wilson Sanchez, Catherine C. Elix, Ivana Alicea, Anamika Basu, Christina Du Ross, Nouri Neamati, Carlos A. Casiano. Repositioning HIV-based small molecule inhibitors of the stress oncoprotein LEDGF/p75 to overcome prostate cancer resistance to taxane chemotherapy. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr B06.

13-year oncologic and functional outcomes and morbidity in men </= 55 years treated with I-125 brachytherapy +/- external beam radiation and/or androgen deprivation.

121 Background: Young patients are most often recommended prostatectomy because few radiation series have reported long-term outcomes specifically for this age group. We now address that deficit by presenting single-institution 13-year oncologic outcomes and morbidity after I-125 prostate brachytherapy (BRT). Methods: Between 1998-2014, 227 patients < 55 years were prospectively followed after PCa treatment with BRT +/- external-beam irradiation +/- androgen deprivation. NCCN risk stratification identified 99 low-, 51 intermediate-, 77 high- + very-high-risk patients treated. Endpoints include Phoenix biochemical control (BC), prostate-cancer-specific survival (PCSS), overall survival (OS), and urinary, bowel, and sexual complications. Results: With a minimum and median follow-up of 26 and 72.3 months, respectively the 13-year actuarial rate of BC, PCSS, and OS for low-risk disease: 97.8%, 100%, 100%, respectively; for intermediate-risk disease: 94.0%, 100%, 88.1%, respectively and for high + very-high-risk disease 83.6%, 89.9%, 77.6%, respectively. Only 3 patients died of prostate cancer. Multivariate analysis demonstrated race, EBRT use, ADT use, PSA > 10, PSA > 20, GS > 7, T3a, T3b, smoking, diabetes as significant for BC and PCSS (p < 0.05). Permanent incontinence occurred only in the one patient who underwent TURP, 4 transient urethral strictures were all successfully dilated, and no other grade 3 intestinal or urinary complications were reported. In the 77.5 % potent at baseline, preservation was reported at 5 and 10-years overall in 75.8 % and 54.6 %, and with PDE5-I, 83.3% preserved potency at 10-years. Conclusions: Patients < 55 years achieve excellent and durable prostate cancer control at 13 years after I125 BRT, most notably in high-risk, with prostate cancer specific mortality uncommon in all but very-high-risk group. Significant urinary or bowel morbidity is uncommon, and potency preservation is expected with PDE5-I. We conclude age < 55 years should not be used to discriminate against LDRBT.

External validation of a prognostic Gleason grade classification system.

123 Background: We aimed to evaluate a recently proposed prognostic Gleason grading system among two distinct cohorts of men receiving treatment for localized PCa with extended clinical follow. Methods: We identified patients receiving treatment with radical prostatectomy (RP) in two settings: an academic referral center and the multi-center Cancer of the Prostate Strategic Urological Research Endeavor (CaPSURE) registry. We examined the independent prognostic ability of the proposed grade groups (3+3; 3+4; 4+3; 4+4; 9-10), adjusted for significant clinical and pathological characteristics, on disease recurrence, defined as two consecutive PSA values ≥ 0.2 ng/mL or receipt of salvage treatment, using Cox proportional hazards models. Adjusted pairwise comparisons were made between grade groups. Distant disease endpoints including metastatic progression and prostate cancer specific mortality (PCSM) were similarly evaluated within the CaPSURE cohort. Results: We identified 1,734 men receiving treatment at UCSF with immediate RP with pathologic assessment consistent with the 2005 ISUP modification, and 4,564 men within the CaPSURE database. Median follow up within the UCSF cohort was 33 months (interquartile range, IQR 16-58) and 91 months (IQR 50-135) within CaPSURE. Relative to Gleason grade 3+3, all prognostic Gleason grade groups were independently associated with risk of recurrence among the UCSF cohort (all p < 0.01). Adjusted pairwise comparisons of biopsy and pathologic Gleason groups, except 4+3 versus 4+4, also were statistically significant. Among the CaPSURE cohort, biopsy and pathologic prognostic Gleason grade groups were independently associated with risk of recurrence, metastatic progression and PCSM, though pairwise distinctions between Gleason 4+3 and 4+4 and Gleason 4+4 versus 9-10 were not significant. This study was limited by the comparatively smaller proportion of men receiving radical prostatectomy for higher Gleason grade ( > 4+4) disease. Conclusions: A proposed prognostic Gleason classification system stratifies men according to the risk of recurrence and downstream endpoints. However, the discrimination of outcomes among higher grade disease appeared less robust.

Explore the characteristics of bladder function of the patients with pelvic organ malignancy

Explore the characteristics of bladder function of the patients with pelvic organ malignancy

Évaluation préthérapeutique du patient candidat à la chirurgie du cancer de la prostate

To determine the tools of therapeutic decision that push towards surgical treatment in non metastatic prostate cancer eligible to local treatment. The optimized assessment of the disease and eventual comorbidities improves the selection of patients. Patient's files will be presented in the uro-oncological multidisciplinary discussions to validate the customized therapeutic approach proposed. Literature review using Medline (National library of medicine, Pubmed) and Med Science databases based on the scientific pertinence. Research was focused on the diagnosis of prostate cancer, the evaluation of the disease and patient's characteristics, and finally the elements that are with a surgical treatment (past medical history, past surgical history, functional status, patient's comorbidities, and life expectancy). The pretherapeutic oncologic evaluation allows to estimate the risks associated with prostate cancer; it is an essential aspect of therapeutic decision. Several clinical, biological, imaging and pathological criteria allow to guide decision-making according to tumor aggressiveness and risk of recurrence, estimating the results of the different treatments proposed. On the other hand, the evaluation of lower urinary tract symptoms, urinary continence and sexual function, the integration of anatomical data, past medical and past surgical history are all essential for the therapeutic decision, in addition to the comorbidities (Charlson, ASA, ICD). These elements should be taken all together in order to decide for a radical or conservative management of PCa, they guide decision-making in patients candidate for surgery. For example, age plays a key role in the choice of treatment, even in older men at risk of developing high-risk PCa that can affect overall survival. The combined evaluation of the patient and disease characteristics is of utmost importance in oncology, and especially in the treatment of non-metastatic PCa. The role of the anesthesiologist in the analysis and interpretation of comorbidities remains primordial and it is essential for the selection of the right candidates for surgery after being well informed, and orienting them toward surgery in agreement with the prerogatives programs of customized care.

Gemcitabine-releasing mesenchymal stromal cells inhibit in vitro proliferation of human pancreatic carcinoma cells

Background aimsPancreatic cancer (pCa) is a tumor characterized by a fibrotic state and associated with a poor prognosis. The observation that mesenchymal stromal cells (MSCs) migrate toward inflammatory micro-environments and engraft into tumor stroma after systemic administration suggested new therapeutic approaches with the use of engineered MSCs to deliver and produce anti-cancer molecules directly within the tumor. Previously, we demonstrated that without any genetic modifications, MSCs are able to deliver anti-cancer drugs. MSCs loaded with paclitaxel by exposure to high concentrations release the drug both in vitro and in vivo, inhibiting tumor proliferation. On the basis of these observations, we evaluated the ability of MSCs (from bone marrow and pancreas) to uptake and release gemcitabine (GCB), a drug widely used in pCa treatment. MethodsMSCs were primed by 24-h exposure to 2000 ng/mL of GCB. The anti-tumor potential of primed MSCs was then investigated by in vitro anti-proliferation assays with the use of CFPAC-1, a pancreatic tumor cell line sensitive to GCB. The uptake/release ability was confirmed by means of high-performance liquid chromatography analysis. A cell-cycle study and secretome evaluation were also conducted to better understand the characteristics of primed MSCs. ResultsGCB-releasing MSCs inhibit the growth of a human pCa cell line in vitro. ConclusionsThe use of MSCs as a “trojan horse” can open the way to a new pCa therapeutic approach; GCB-loaded MSCs that integrate into the tumor mass could deliver much higher concentrations of the drug in situ than can be achieved by intravenous injection.

Abstract 4659: Hyaluronan: A novel target of dietary flavonoid fisetin in prostate cancer

Abstract Prostate cancer (PCa) is one of the most prevalent cancers affecting males in western countries. Many therapeutic strategies are available for treatment of PCa but cancer relapses in ∼10-50% of cases. Hyaluronan (HA), an extracellular glycosaminoglycan, is primarily synthesized by HA synthase (HAS) enzymes HAS-1, -2 and -3. In the undiseased state, HA regulates several cellular functions such as reepithelization, tissue healing, wound repair and brain development. Elevated HA levels have been shown to be associated with aggressiveness and disease progression in certain cancer cell types. We observed increased levels of HA in human PCa cells compared to normal prostate epithelial cells. Prostate tissues from TRAMP, a spontaneous murine PCa progression model, exhibited gradual increase in HA levels with disease progression. Serum samples and prostate tissues from human PCa patients showed significant increase in HA levels that correlated with advance in disease stage. Notably, all PCa cell lines expressed both HAS-2 and -3 at much higher levels compared to normal prostate epithelial cells. Identifying a dietary non-toxic inhibitor at achievable concentrations that can effectively suppress HAS levels and lessens HA production can significantly improve the disease outcome. Epidemiological studies over the past decade have identified plant-based diet rich in flavonoids as an attractive option in cancer prevention and therapy. Fisetin, found in many fruits and vegetables belongs to the flavonol subgroup of flavonoids and has shown potential to be effective against PCa. Using discovery based metabolomics, we identified HA as a novel target of the dietary flavonoid fisetin. In vitro studies in MNU-6 model, a unique family of human PCa cell lines (NrPEC, RWPE, NA22, NB14, NB11 and NB26) that mimics multiple steps of prostate carcinogenesis, with fisetin treatment (40μM: 48h) decreased HA levels and inhibited cell growth and proliferation. HA interaction with its primary receptor CD44 results in activation of pSTAT3, pSrc, MMP-2, MMP-9 proteins. Fisetin treatment of tumorogenic NB11 and NB26 cells inhibited protein expression of pSTAT3, pSrc, MMP-2, and -9. To establish in-vivo relevance of these in-vitro findings, we determined HA levels in two different murine models. LC-MS/MS analysis of tumors from athymic nude mice xenografted with tumorogenic NB11 and NB26 cells showed a significant decrease in HA abundance in fisetin treated animals. Moreover, reduced HA levels in fisetin-treated TRAMP mice were associated with inhibition of PCa development and increased survival. This study establishes that fisetin is a HAS inhibitor and a potential agent for treating human PCa. Modulation of HA using fisetin may be a viable option for augmenting the current standard of care in PCa patients. Citation Format: Rahul K. Lall, Mohammad Imran Khan, Deeba N. Syed, Vaqar M. Adhami, Hasan Mukhtar. Hyaluronan: A novel target of dietary flavonoid fisetin in 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 4659. doi:10.1158/1538-7445.AM2015-4659

Abstract 4312: A novel miRNA-based predictive model for biochemical failure following post-prostatectomy salvage radiation therapy

Abstract Prostate cancer (PCa) is the second most common cancer among men worldwide. Radical prostatectomy (RP) is a standard treatment for PCa, yet 30-40% of these men experience biochemical failure (BF) and must undergo additional treatment such as radiation therapy (RT). Unfortunately, a subset of these patients develop resistance to RT and have disease progression. It is important to stratify men based on risk of recurrence as well as identify the most suitable treatment approach to take in PCa to reduce non-necessary patient burden. Currently used methods that include clinical and histopathological factors lack disease specificity and sensitivity. A more informative classification system is needed and molecular biomarkers may serve to bridge the gap of the inadequacies of current prognostic and predictive methods. There were two major objectives for this study. The first was to identify microRNA (miRNA) signatures that predict time to BF post-RP. Secondly, and most novel to the field of RT, we sought to determine miRNAs that could predict BF following post-RP salvage RT as well as develop a new model using both miRNAs and clinical factors. Using the NanoString Human v2 array, we profiled 800 miRNAs in forty-three PCa patients that all experienced BF post-RP and subsequently underwent salvage RT. We identified an 88-miRNA signature that could predict time to BF post-RP using multivariate Cox regression analysis. We observed that these 88 miRNAs could classify patients into two groups (early vs late BF) and that the probabilities to the time to first BF were significantly different between the groups. To identify miRNAs that could independently predict BF post-salvage RT, we performed a multivariate Cox regression analysis with lymph node status and Gleason score which lead to the discovery of nine miRNAs. We wanted to not only identify miRNAs that could independently predict BF post-salvage RT, but also develop a model using these miRNAs in combination with currently used clinical factors to improve upon existing methods. We performed a Cox regression analysis including lymph node status, Gleason score, and the 9 independently identified miRNAs and applied a step-wise model selection strategy to determine the best predictive miRNAs. Two miRNAs with Gleason score and lymph node status had the best predictability. Further specificity and sensitivity analysis indicated that the addition of these miRNAs greatly improved the predictive ability of lymph node status and Gleason score alone (AUC = 0.83 vs 0.66). To the best of our knowledge, this is the first report correlating molecular biomarkers with response to salvage RT. This research has the potential to greatly impact future treatment strategies by using molecular biomarker profiles alone or in combination with other clinical factors to assign the most suitable therapy to individuals the first time and thus avoid over or under treatment. Citation Format: Erica Hlavin Bell, Simon Kirste, Jessica L. Fleming, Petra Stegmaier, Vaness Drendel, Xiaokui Mo, Stella Ling, Denise Fabian, Isabel Manring, Cordula A. Jilg, Wolfgang Schultze-Seemann, Maureen McNulty, Debra L. Zynger, Douglas Martin, Julia White, Martin Werner, Anca L. Grosu, Arnab Chakravarti. A novel miRNA-based predictive model for biochemical failure following post-prostatectomy salvage radiation therapy. [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 4312. doi:10.1158/1538-7445.AM2015-4312

Abstract 4836: Presence of FTO rs9939609 and rs9930506 and severity of prostate cancer in Puerto Ricans

Abstract Prostate cancer (PCa) mortality in Puerto Rico (PR) is significantly higher (28.3/100,000 men) compared to US mainland Hispanics. Obesity is prevalent in PR and has been associated with PCa mortality and aggressiveness. Polymorphisms rs9939609 and rs9930506 in the FTO gene have been associated with both obesity and PCa in other populations. Previous work in our laboratory has shown that Puerto Rican patients who underwent radical prostatectomy (RP) and also had at least one G allele in the FTO rs9930506 polymorphism exhibited a greater likelihood for low severity PCa. The aim of this work was to ascertain whether the presence of both polymorphisms (rs9930506 and rs9939609) in tandem correlated with PCa severity in this Puerto Rican population. The study population consisted of the pathology specimens of 294 Puerto Rican PCa patients, aged 40-79 years old who underwent RP as definitive treatment for PCa. Genomic DNA was extracted from normal seminal vesicle paraffin-embedded tissue. Polymorphisms were determined by RT-PCR. PCa severity was defined based on RP stage and Gleason Score. Chi-square test and logistic regression models were used to assess the correlation between FTO gene polymorphisms and PCa severity. Other factors such as BMI and age were considered in the model. We found that the A/G SNP in rs9930506 was present in 135 patients (45.9%). Likewise for rs9939609 we found the A/T SNP in 138 patients (46.9%). We found no statistically significant relationship between either polymorphism by itself and PCa severity. In 104 (35.4%) patients both SNPs were heterozygous. Of these, 77 (74%) were overweight or obese. Within this latter group, 55 (71.4%) exhibited low severity PCa. Data showed that those patients with simultaneous heterozygous forms had about 12% lower odds of low severity of PCa (95% CI: 0.52, 1.50), although no statistical significance was found for this relationship (p = 0.640). These results suggest that the presence of both polymorphisms in their heterozygous form may be related to low severity PCa in the obese/overweight group. Further studies are needed to understand the mechanisms that may be involved in this modulation of the development of severity in PCa in this population. This project was supported by RCMI grant G12MD007600 (Center for Collaborative Research in Health Disparities) and grant 8U54MD007587-03 (Puerto Rico Clinical and Translational Research Consortium) from the National Institute on Minority Health and Health Disparities, and by Award Grant Number# CA096297/CA096300 from the National Cancer Institute of the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Citation Format: Jeannette Salgado-Montilla, Jorge Rodríguez-Caban, Lorena Gonzalez-Sepulveda, Ricardo Sanchez-Ortiz, Margarita Irizarry-Ramirez. Presence of FTO rs9939609 and rs9930506 and severity of prostate cancer in Puerto Ricans. [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 4836. doi:10.1158/1538-7445.AM2015-4836

PC-1/PrLZ confers resistance to rapamycin in prostate cancer cells through increased 4E-BP1 stability.

An important strategy for improving advanced PCa treatment is targeted therapies combined with chemotherapy. PC-1, a prostate Leucine Zipper gene (PrLZ), is specifically expressed in prostate tissue as an androgen-induced gene and is up-regulated in advanced PCa. Recent work confirmed that PC-1 expression promotes PCa growth and androgen-independent progression. However, how this occurs and whether this can be used as a biomarker is uncertain. Here, we report that PC-1 overexpression confers PCa cells resistance to rapamycin treatment by antagonizing rapamycin-induced cytostasis and autophagy (rapamycin-sensitivity was observed in PC-1-deficient (shPC-1) C4-2 cells). Analysis of the mTOR pathway in PCa cells with PC-1 overexpressed and depressed revealed that eukaryotic initiation factor 4E-binding protein 1(4E-BP1) was highly regulated by PC-1. Immunohistochemistry assays indicated that 4E-BP1 up-regulation correlates with increased PC-1 expression in human prostate tumors and in PCa cells. Furthermore, PC-1 interacts directly with 4E-BP1 and stabilizes 4E-BP1 protein via inhibition of its ubiquitination and proteasomal degradation. Thus, PC-1 is a novel regulator of 4E-BP1 and our work suggests a potential mechanism through which PC-1 enhances PCa cell survival and malignant progression and increases chemoresistance. Thus, the PC-1-4E-BP1 interaction may represent a therapeutic target for treating advanced PCa.

Lycorine is a novel inhibitor of the growth and metastasis of hormone-refractory prostate cancer.

Lycorine, a natural alkaloid extracted from the Amaryllidaceae plant family, has been reported to exhibit a wide range of physiological effects, including the potential effect against cancer. However, the anti-prostate cancer (PCa) efficacy of Lycorine remains unrevealed. In this context, we figured out Lycorine's anti-proliferative and anti-migratory properties for PCa treatment. Lycorine inhibited proliferation of various PCa cell lines, induced cell apoptosis and cell death. Here we showed that Lycorine decreased proliferation, migration, invasion, survival and EMT of prostate cancer cell lines. Subcutaneous and orthotopic xenotransplantations by ectopic implantation of the human hormone-refractory PC-3M-luc cells were used to confirm in vivo anticancer effects of Lycorine. Lycorine inhibited both growth and metastasis in multiple organs (liver, lung, kidney, spleen and bone) in vivo and improved mice survival. Lycorine prevented EGF-induced JAK/STAT signaling. Importantly, anti-cancer effects of Lycorine were dependent on STAT expression. We suggest that Lycorine is a potential therapeutic in prostate cancer.

MP57-14 INTRAOPERATIVE MOLECULAR DIAGNOSTIC IMAGING CAN IDENTIFY RENAL CELL CARCINOMA DURING NEPHRECTOMY

open surgery. Only 1 patient in PCA group required a reintervention performed by radiological embolization. Both groups had a comparable mean postoperative serum creatinine and eGFR was stable over time in both groups. According to Clinical Practice Guideline for Acute Kidney Injury (AKI) only 5% of patients had an acute compromise renal function (AKI Stage 1) which resolved in a few days. At Univariate and Multivariate analysis predictors of Recurrence Disease (RD) included PADUA Score 8 (HR 1⁄4 9.99) and ASA risk 4 (HR 1⁄4 11.23). Limitations of our study are: limited follow-up, oncologic outcomes based only on radiographic criteria and lack of pathologic data in some cases. CONCLUSIONS: Our multicentric analysis shows that oncologic outcomes and complication rate in PCA treatment and LCA treatment have no statistical difference. Both treatments are safe and effective is the management of cT1 solid renal masses in patients who are poor candidates for conventional surgery. Longer follow-up is required to truly interpret oncologic outcomes after cryoablation.

Androgen deprivation therapy (ADT) plus docetaxel (D) versus ADT alone for hormone-naïve metastatic prostate cancer (PCa): Long-term analysis of the GETUG-AFU 15 phase III trial.

140 Background: ADT is standard treatment for metastatic PCa. Recently, the E3805 trial reported a survival benefit for (ADT+D) in high volume disease (HVD) patients, whereas the GETUG-15 trial did not demonstrate a survival improvement among a less selected group of patients (pts) with hormone-naïve metastatic PCa. We report an updated analysis of overall survival (OS) of the GETUG 15 trial and aligned the definition of HVD and low volume disease (LVD) subgroups. Methods: Long-termOS was analyzed in the intention-to-treat population (n=385 pts). Additionally, we retrospectively assessed the tumor volume as defined per E3805criteria in all patients enrolled in GETUG 15. Results: See Table. With a median follow-up of 82.9 months (95%CI [80.5-84.3]) (vs 50 months (95%CI [80.5-84.3] in the original analysis), 212 patients (55%) have died. The median OS is 46.5 [39.1-60.6] and 60.9 months [46.1-71.4] in the ADT and in the ADT + D arms, respectively (HR: 0.9 [95%CI: 0.7-1.2]). In HVD patients (n=183, 47.5%), median OS rates were 35.1 months [29.9-44.2] in the ADT alone arm and 39 months [28-52.6] in the ADT+D arm (HR: 0.8 [0.6-1.2]). Conclusions: With longer follow-up, the addition of docetaxel to ADT did not significantly improve OS in patients with hormone-naïve metastatic prostate cancer. In the retrospective analysis using aligned definition of volume of metastasis as E3805, the HVD outcomes were similar to E3805 for ADT alone and there was a non-significant 4 months increase in OS with ADT+D, in this underpowered subset. Clinical trial information: 00104715. [Table: see text]

Cytoreductive radical prostatectomy in patients with prostate cancer and low-volume skeletal metastases: Results of a feasibility and case-control study.

176 Background: Androgen deprivation (ADT) represents the standard treatment for PCA with osseous metastases. We explored the role of cytoreductive radical prostatectomy in PCA with low volume skeletal metastases in terms of a feasibility study. Methods: 32 patients with biopsy proven PCA, minimal osseous metastases (≤ 3 hot spots on bone scan), absence of visceral or extensive lymph node metastases and PSA decrease to < 1.0 ng/ml after neoadjuvant ADT were included in the feasibility study. 38 men with metastatic PCA who were treated by ADT without local therapy served as control group (group B). Surgery-related complications, biochemical progression-free, symptomatic-free, cancer-specific and overall survival were analyzed using descriptive statistical analysis. Results: Mean age was 61 (42-69) and 64 (47-83) years in group A and B, respectively, with similar patient characteristics in terms of initial PSA, biopsy Gleason score, clinical stage, extent of metastatic disease. The mean follow-up was 40.6 (3-71) and 44 (24-96) months in group A and B, respectively. Pathohistology revealed vital PCA with metastatic potential in all 32 patients despite neoadjuvant ADT. 12% of pts in group A developed Clavien grade III complications. According to the ICSmaleSF questionnaire 30/32 (93.7%) pts were continent. Patients in group A experienced significantly better bPFS (36.8 versus 23.1 months, p=0.042), clinical PFS (38.6 versus 26.5 months, p=0.032) and cancer specific survival rate (95.6% versus 84.2%, p=0.043) whereas the overall survival was similar. 0% and 29% of men in group A and B, respectively, underwent palliative surgical procedures for locally progressing PCA. Conclusions: CRP is feasible with good functional and oncological results in well selected men with metastatic PCA who respond well to neoadjuvant ADT. These men have a long life expectancy and CRP reduces the risk of locally recurrent PCA and local complications. CRP might be a treatment option in the multimodality management of PCA with minimal osseous metastases.

Abstract B11: Stromal response to prostate cancer therapeutics

Abstract Docetaxel (D) is a clinically used front-line chemotherapeutic agent for castration resistant advanced prostate cancer (Pca). However, its long-term benefits are limited, with most patients eventually progressing because of inherent or acquired drug resistance. The treatment of advanced Pca is a significant challenge and there are no effective treatments that stably suppress the disease. The mechanisms behind the resistance to Docetaxel are not fully understood. It is well accepted that tumor microenvironment is essential for tumor cells survival, cancer progression and metastasis. However, the mechanisms by which tumor cells interact with their surrounding at different stages of cancer development or during chemotherapy are largely unidentified. The central goal is to identify the cellular and biochemical responses of stromal cells in tumor microenvironment with which prostate cancer cells interact. Specifically, the interaction of prostate cancer cells with stromal cells of the prostate or the bone microenvironment in the presence of clinically used cancer therapeutics will be examined. Key regulators of these interactions will also be identified. Such regulators include cytokines, growth factors, proteins, and their receptors. By identifying these regulators and their contribution to tumor drug response, novel therapeutics targeted to the microenvironment can be developed. Therefore, we hypothesize that the response of prostate stromal cells exposed to chemotherapeutic agents could modify drug response or therapeutic outcome of prostate cancer. Cellular proliferation was analyzed by MTT assay. The IC50 of Docetaxel for WPMY-1 (normal stromal), LNCaP (androgen dependent), DU-145 (androgen independent), and HS27A (bone stromal) showed inhibitory effects between 2-10nM. Cell cycle profiles were assessed by flow cytometry. The analysis showed that Docetaxel (2-50nM) induced prominent G2-M arrest in prostate and stromal cells within 24 hours. Gene expression profiling of prostate cancer and stromal cells lines were evaluated. To obtain the expression profiles, we conducted a human cytokines and chemokines array, which consisted of 84 specific genes. Analysis of the prostate cancer and stromal cells treated with Docetaxel revealed differential expression patterns. These results suggest Docetaxel exhibits strong anti-proliferative effects and analysis of the gene array suggest regulation of genes associated with, cell growth, survival, proliferation, metastasis, angiogenesis, and apoptosis. Note: This abstract was not presented at the conference. Citation Format: Dominique Nicole Gales, Khalda Fadlalla, Upender Manne, Clayton Yates, Temesgen Samuel. Stromal response to prostate cancer therapeutics. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Drug Sensitivity and Resistance: Improving Cancer Therapy; Jun 18-21, 2014; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(4 Suppl): Abstract nr B11.

Abstract 2142: Plumbagin, a medicinal plant-derived 1,4-napthoquinone, inhibits prostate carcinogenesis in intact and castrated Pten knockout mice by modulation of tumor microenvironment

Abstract Prostate specific Pten conditional knockout (PtenLoxP/LoxP:PB-Cre+4) (Pten-KO)) mice are unique preclinical model to evaluate agents for efficacy for both prevention and treatment of PCa. We present here for the first time that dietary plumbagin (PL) inhibits tumor development in intact as well as castrated Pten-KO mice. PL was mixed in an antioxidant free basal powdered diet and was given at two dose levels (200 and 500 ppm). Mice (4 wks old) were divided into three groups (Control (n=40), PL (200 ppm) (n=20), and PL (500 ppm) (n=40). Mice were sacrificed at 15 and 30 wks of age. To determine the prostate tumor volume, we carried out micro-PET/CT analysis of control and PL treated groups mice at 30 wks using a tumor selective radiopharmaceutical agent 124I-NM404. PL treatment (200 and 500 ppm) resulted in a dose-dependent decrease (p<0.01) in prostate tumor volume. PL treatment also resulted in a significant (P<0.001) decrease in weights of prostate tumors and urogenital apparatus at 15 and 30 wks. Histopathological analyses revealed inhibition of prostatic intraepithelial neoplasia (PIN) to invasive adenocarcinoma at 15 and 30 wks. PL treated mice also showed a significant (P<0.01) inhibition of small invasive adenocarcinoma with cystic change at 30 wks. To determine the effects of PL in castrated resistant prostate cancer (CRPC), we castrated 26 Pten-KO mice at 10 wks and divided into 2 groups. PL treatment was started one wk after castration and continued until 50 wks. At 50 wks, castrated control Pten-KO mice illustrated atrophy of prostate tumors. PL treatment (500 ppm) further resulted in a significant decrease of prostate tumors weight of castrated Pten-KO mice. Histopathological analysis of PL treated mice prostate tumors showed significant decrease of both invasive adenocarcinoma and cystic change. Biochemical analyses of Pten-KO mice prostate tumors elicited a constitutive activation of AKT, protein kinase C epsilon (PKCϵ), signal transducer and activators of transcription 3 (Stat3) and increased COX2 expression compared to wild type mice. PL treatment resulted in decreased expression of PKCϵ, Stat3 and COX2 compared to control mice. We also observed that PL targets tumor associated macrophages (TAM) in prostate tumors. Prostate tumors of PL treated mice showed an increased infiltration of M1 macrophages and inhibition of M2 macrophages, as analyzed by immunohistochemical staining of F4/80, iNOS and L-arginase. PL treatment also inhibited the expression of vimentin and slug, the markers of epithelial to mesenchymal transition (EMT) in prostate tumors. In summary, the results indicate that dietary PL inhibits growth of both primary and CRPC, which was accompanied inhibition of EMT and modulation of tumor microenvironment. We conclude that PL may be worthy of evaluation for the prevention and treatment of human PCa (Support: CA138761). Citation Format: Bilal B. Hafeez, Joseph W. Fischer, Ashok Singh, Ala Mustafa, Louise Meske, Ajit K. Verma. Plumbagin, a medicinal plant-derived 1,4-napthoquinone, inhibits prostate carcinogenesis in intact and castrated Pten knockout mice by modulation of tumor microenvironment. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2142. doi:10.1158/1538-7445.AM2014-2142

Abstract 3790: Artesunate inhibits multiple proinflammatory transcription factors leading to the suppression of growth and induction of apoptosis in prostate cancer cells

Abstract Prostate cancer (PCa) is common and a frequent cause of cancer death among men worldwide. Moreover, PCa rates have risen quite significantly in the last decade in Singapore men and although some of the increase can be attributed to enhanced detection, much of the increased incidence is associated with genetic alterations and life-style related factors. Current therapies for metastatic prostate cancer are only marginally effective, and hence new treatment modalities are urgently needed. Considerable evidence suggests that chronic inflammation plays a pivotal role in the development and progression of PCa. Thus, the agents that can suppress inflammatory mediators have a potential in treatment of PCa. One way to expedite drug development is to find new uses for drugs already in clinical use. Hence we propose to investigate the role of artesunate, (a drug approved for the treatment of multidrug-resistant malaria) in PCa using diverse prostate cancer cell lines. In this study, we investigated the effect of artesunate (ART) primarily on signal transducer and activator of transcription 3(STAT3) signaling pathway in both androgen independent (DU145) and androgen dependent (LNCaP) PCa cell lines and also prospectively tested the hypothesis of NF-κB and STAT3 inhibition using a virtual predictive functional proteomics tumor pathway technology platform. We found that ART inhibited constitutive and IL-6-induced activation of STAT3 in DU145 and LNCaP cells in a dose and time dependent manner. We observed that STAT3 suppression by ART was mediated through the inhibition of activation of upstream kinases such as (c-Src, JAK1, and JAK2) and generation of reactive oxygen species (ROS) was also involved in this process. Our preliminary findings further indicate that ART also suppressed constitutive NF-κB activation in PCa cells. ART exhibited significant anti-proliferative effects and abrogated the migratory/invasive potential of PCa cells. Moreover, ART down-regulated the expression of various NF-κB and STAT3 regulated gene products involved in proliferation, survival and angiogenesis, also induced apoptosis in PCa cells lines as evident by DNA fragmentation and Annexin V staining. Overall our preliminary results from experimental and predictive studies indicate that ART mediates its anti-tumor effects through suppression of NF-κB and STAT3 pathways in PCa. Citation Format: Alamelu Nachiyappan, Muthu K Shanmugam, Feng Li, Alan Prem Kumar, Gautam Sethi. Artesunate inhibits multiple proinflammatory transcription factors leading to the suppression of growth and induction of apoptosis in prostate cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3790. doi:10.1158/1538-7445.AM2014-3790

Abstract 1151: SIRT6 induces EMT and promotes cancer cell invasion and migration in prostate cancer

Abstract Prostate cancer (PCa) is the most common cancer and the second leading cause of cancer related death in males in the developed countries. One of the major clinical challenges is the propensity for advanced PCa to metastasize to bone or other organs, which is primarily responsible for its effect on patient mortality. SIRT6, one of Sirtuins family members, is an important histone modifying protein that regulates diverse physiological functions such as aging and metabolism. Recently there is much evidence showing an involvement of SIRT6 in tumorigenesis. At present, relatively little is known about the role of SIRT6 in regulating prostate cancer or metastasis. In our study, we have used both prostate tumor tissues and prostate cancer cell lines to study the roles of SIRT6 in the development and progression of PCa. From deposited gene profiling studies we found that SIRT6 was overexpressed in prostate tumors, compared with normal prostate tissues. Tissue microarray studies confirmed the higher levels of SIRT6 in both prostate tumor tissues and prostate cancer cells than in their normal counterparts. Depletion of SIRT6 by siRNA inhibited PCa cell proliferation. Bioinformatics analysis of the databases revealed that the high SIRT6 expression was associated with markedly shorter window of clinical recurrence, and the expression level of SIRT6 was significantly higher in PCa tissue with Gleason grade greater than seven. Further analysis indicated that SIRT6 expression increased along with the metastasis of PCa. We used PC-3 and DU145 cells to study whether SIRT6 could play a role in the migration and invasion of PCa cells. Indeed, SIRT6-deficiency markedly reduced cell migration and invasion. Compared with control siRNA treated cells, the protein level of N-cadherin reduced while E-cadherin level showed an increase after SIRT6 knockdown. We further revealed that SIRT6 regulated EMT-inducing transcription factor expression in PCa cells. Taken together, our findings indicate that SIRT6 is up-regulated in PCa, and the high expression of SIRT6 plays an important role in the progression of PCa as it facilitates cancer cell migration and invasion, and possibly metastasis. These data also suggest the therapeutic value of targeting SIRT6 in the treatment of metastatic PCa. Citation Format: Qian Xie, Alice ST Wong, Weiliang Xia. SIRT6 induces EMT and promotes cancer cell invasion and migration in prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1151. doi:10.1158/1538-7445.AM2014-1151

Abstract 3773: Identification of ALDH1A3 as a driver of resistance to both low-dose metronomic and conventional cyclophosphamide chemotherapy in prostate cancer

Abstract Prostate cancer (PCa) is the most common cancer in North American males. Conventional, maximum tolerated dose (MTD) chemotherapy with cyclophosphamide (CPA) has been used in the past for PCa treatment, but has been replaced by docetaxel. However, renewed interest in CPA is emerging given its frequent use in low-dose metronomic (LDM) chemotherapy regimens known for their antiangiogenic properties. While therapeutic resistance limits the clinical utility of both LDM and MTD CPA, such resistance appears to occur through at least partially distinct mechanisms. To investigate the molecular changes contributing to resistance formation, we have generated LDM and MTD CPA resistant PC-3 human prostate cancer cell variants (LCR and MCR, respectively), and corresponding control variants (NS), through in vivo passaging in mice. Using next-generation sequencing and gene expression analysis, we observed 453 differentially regulated genes in LCR vs NS, and 1141 genes in MCR vs NS. An intersecting set of 158 genes found to be differentially expressed in both resistant tumor cell lines was further characterized. The genes most up-regulated (including ALDH1A3, MAGEA2 and ELOVL2) and down-regulated (comprising FN1, IL8 and IGFBP3) were chosen for validation by qRT-PCR studies. We also undertook pathway analysis using the DAVID database and the Reactome FI Cytoscape Plugin. Collectively, our studies revealed that glycolysis/gluconeogenesis, biosynthesis of unsaturated fatty acids and activated drug metabolism may contribute to resistance to both LDM and MTD CPA. In addition, numerous chemokine signaling pathway-related genes were found to be downregulated. Current studies are focusing on the role of ALDH1A3 in LDM and MTD CPA resistance. ALDH1A3 is amongst the most differentially regulated genes found in our analysis, and it has been associated with chemotherapy resistance, ‘stemness’ and aggressive tumor behaviour. Despite different mechanisms of action, there are overlapping mechanisms of resistance to LDM and MTD CPA chemotherapy. If our studies confirm an essential role of ALDH13A in such resistance, this could be rapidly clinically translated by repurposing approved pharmacological ALDH inhibitors as anticancer agents. Citation Format: Van C. Hoang, Annabelle Chow, Amy Wong, Lavarnan Sivanathan, Urban Emmenegger. Identification of ALDH1A3 as a driver of resistance to both low-dose metronomic and conventional cyclophosphamide chemotherapy in prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3773. doi:10.1158/1538-7445.AM2014-3773

Flexibility in Men's Sexual Practices in Response to Iatrogenic Erectile Dysfunction after Prostate Cancer Treatment.

IntroductionProstate cancer (PCa) treatments are associated with a high incidence of erectile dysfunction (ED). Interventions to help men with iatrogenic ED have largely focused on penile tumescence adequate for vaginal penetration. Less research has been undertaken on sex practices other than penile/vaginal intercourse.AimThe aim of this study was to explore forms of sexual practice engaged in by men following treatment for PCa. We focused in particular on anal intercourse (AI) as practiced by both nonheterosexual (i.e., gay-identified men and other men who have sex with men) and heterosexual men. We sought to determine how common AI was subsequent to PCa treatment and how flexible AI practitioners were in their modes (e.g., from insertive to receptive) when faced with iatrogenic ED.MethodsAn international online survey was conducted in 2010–2011 of men treated for PCa, where participants (N = 558) were asked explicitly about their sexual practices before and after PCa treatment.Main Outcome MeasuresThe outcome measures were the numbers and percentages of men who practiced AI before and after PCa treatment as well as the percentage who changed AI practice after PCa treatment.ResultsFive hundred twenty-six men (90 nonheterosexual men; 436 heterosexual men) answered questions on AI practices. A proportion of nonheterosexual (47%) and heterosexual men (7%) practiced AI following PCa treatment, and did so in all modes (insertive, receptive, and “versatile”). Many nonheterosexual men continued to be sexually active in the face of iatrogenic ED by shifting from the insertive to receptive modes. A few men, both heterosexual and nonheterosexual, adopted AI for the first time post-PCa treatment.ConclusionsFlexibility in sexual practice is possible for some men, both nonheterosexual and heterosexual, in the face of iatrogenic ED. Advising PCa patients of the possibilities of sexual strategies that include AI may help them in reestablishing a sex life that is not erection dependent. Dowsett GW, Lyons A, Duncan D, and Wassersug RJ. Flexibility in men's sexual practices in response to iatrogenic erectile dysfunction after prostate cancer treatment. Sex Med 2014;2:115–120.