Hormone Ablation Research Articles

Tissue injury and hypoxia promote malignant progression of prostate cancer by inducing CXCL13 expression in tumor myofibroblasts.

Prostate cancer (PC) is a slowly progressing malignancy that often responds to androgen ablation or chemotherapy by becoming more aggressive, acquiring a neuroendocrine phenotype, and undergoing metastatic spread. We found that B lymphocytes recruited into regressing androgen-deprived tumors by C-X-C motif chemokine 13 (CXCL13), a chemokine whose expression correlates with clinical severity, play an important role in malignant progression and metastatic dissemination of PC. We now describe how androgen ablation induces CXCL13 expression. In both allografted and spontaneous mouse PC, CXCL13 is expressed by tumor-associated myofibroblasts that are activated on androgen ablation through a hypoxia-dependent mechanism. The same cells produce CXCL13 after chemotherapy. Myofibroblast activation and CXCL13 expression also occur in the normal prostate after androgen deprivation, and CXCL13 is expressed by myofibroblasts in human PC. Hypoxia activates hypoxia-inducible factor 1 (HIF-1) and induces autocrine TGF-β signaling that promotes myofibroblast activation and CXCL13 induction. In addition to TGF-β receptor kinase inhibitors, myofibroblast activation and CXCL13 induction are blocked by phosphodiesterase 5 (PDE5) inhibitors. Both inhibitor types and myofibroblast immunodepletion block the emergence of castration-resistant PC in the transgenic adenocarcinoma of the mouse prostate (TRAMP) model of spontaneous metastatic PC with neuroendocrine differentiation.

Polysaccharopeptide enhanced the anti-cancer effect of gamma-tocotrienol through activation of AMPK.

BackgroundProstate cancer (PCa) frequently relapses after hormone ablation therapy. Unfortunately, once progressed to the castration resistant stage, the disease is regarded as incurable as prostate cancer cells are highly resistant to conventional chemotherapy.MethodWe recently reported that the two natural compounds polysaccharopeptide (PSP) and Gamma-tocotrienols (γ-T3) possessed potent anti-cancer activities through targeting of CSCs. In the present study, using both prostate cancer cell line and xenograft models, we seek to investigate the therapeutic potential of combining γ-T3 and PSP in the treatment of prostate cancer.ResultWe showed that in the presence of PSP, γ-T3 treatment induce a drastic activation of AMP-activated protein kinase (AMPK). This was accompanied with inactivation of acetyl-CoA carboxylase (ACC), as evidenced by the increased phosphorylation levels at Ser 79. In addition, PSP treatment also sensitized cancer cells toward γ-T3-induced cytotoxicity. Furthermore, we demonstrated for the first time that combination of PSP and γ-T3 treaments significantly reduced the growth of prostate tumor in vivo.ConclusionOur results indicate that PSP and γ-T3 treaments may have synergistic anti-cancer effect in vitro and in vivo, which warrants further investigation as a potential combination therapy for the treatment of cancer.

Luteolin, ellagic acid and punicic acid are natural products that inhibit prostate cancer metastasis.

Prostate cancer (PCa) is the second cause of cancer deaths in men in the USA. When the cancer recurs, early stages can be controlled with hormone ablation therapy to delay the rate of cancer progression but, over time, the cancer overcomes its hormone dependence, becomes highly aggressive and metastasizes. Clinical trials have shown that pomegranate juice (PJ) inhibits PCa progression. We have previously shown that the PJ components luteolin (L), ellagic acid (E) and punicic acid (P) together inhibit growth of hormone-dependent and -independent PCa cells and inhibit their migration and chemotaxis towards CXCL12, a chemokine that is important in PCa metastasis. On the basis of these findings, we hypothesized that L+E+P inhibit PCa metastasis in vivo. To test this possibility, we used a severe combined immunodeficiency mouse model in which luciferase-expressing human PCa cells were injected subcutaneously near the prostate. Tumor progression was monitored with bioluminescence imaging weekly. We found that L+E+P inhibits PC-3M-luc primary tumor growth, inhibits the CXCL12/CXCR4 axis for metastasis and none of the tumors metastasized. In addition, L+E+P significantly inhibits growth and metastasis of highly invasive Pten (-/-) ;K-ras (G12D) prostate tumors. Furthermore, L+E+P inhibits angiogenesis in vivo, prevents human endothelial cell (EC) tube formation in culture and disrupts preformed EC tubes, indicating inhibition of EC adhesion to each other. L+E+P also inhibits the angiogenic factors interleukin-8 and vascular endothelial growth factor as well as their induced signaling pathways in ECs. In conclusion, these results show that L+E+P inhibits PCa progression and metastasis.

The tyrosine kinase inhibitor nilotinib has antineoplastic activity in prostate cancer cells but up-regulates the ERK survival signal—Implications for targeted therapies

BackgroundNovel therapeutic options beyond hormone ablation and chemotherapy are urgently needed for patients with advanced prostate cancer. Tyrosine kinase inhibitors (TKIs) are an attractive option as advanced prostate cancers show a highly altered phosphotyrosine proteome. However, despite favorable initial clinical results, the combination of the TKI dasatinib with docetaxel did not result in improved patient survival for reasons that are not known in detail. MethodsThe National Cancer Institute–Approved Oncology Drug Set II was used in a phenotypic drug screen to identify novel compounds with antineoplastic activity in prostate cancer cells. Validation experiments were carried out in vitro and in vivo. ResultsWe identified the TKI nilotinib as a novel compound with antineoplastic activity in hormone-refractory prostate cancer cells. However, further analyses revealed that treatment with nilotinib was associated with a significant up-regulation of the phospho-extracellular-signal-regulated kinases (ERK) survival signal. ERK blockade alone led to a significant antitumoral effect and enhanced the cytotoxicity of nilotinib when used in combination. ConclusionsOur findings underscore that TKIs, such as nilotinib, have antitumoral activity in prostate cancer cells but that survival signals, such as ERK up-regulation, may mitigate their effectiveness. ERK blockade alone or in combination with TKIs may represent a promising therapeutic strategy in advanced prostate cancer.

FOXA1 deletion in luminal epithelium causes prostatic hyperplasia and alteration of differentiated phenotype

The forkhead box (Fox) superfamily of transcription factors has essential roles in organogenesis and tissue differentiation. Foxa1 and Foxa2 are expressed during prostate budding and ductal morphogenesis, whereas Foxa1 expression is retained in adult prostate epithelium. Previous characterization of prostatic tissue rescued from embryonic Foxa1 knockout mice revealed Foxa1 to be essential for ductal morphogenesis and epithelial maturation. However, it is unknown whether Foxa1 is required to maintain the differentiated status in adult prostate epithelium. Here, we employed the PBCre4 transgenic system and determined the impact of prostate-specific Foxa1 deletion in adult murine epithelium. PBCre4/Foxa1loxp/loxp mouse prostates showed progressive florid hyperplasia with extensive cribriform patterning, with the anterior prostate being most affected. Immunohistochemistry studies show mosaic Foxa1 KO consistent with PBCre4 activity, with Foxa1 KO epithelial cells specifically exhibiting altered cell morphology, increased proliferation, and elevated expression of basal cell markers. Castration studies showed that, while PBCre4/Foxa1loxp/loxp prostates did not exhibit altered sensitivity in response to hormone ablation compared with control prostates, the number of Foxa1-positive cells in mosaic Foxa1 KO prostates was significantly reduced compared with Foxa1-negative cells following castration. Unexpectedly, gene expression profile analyses revealed that Foxa1 deletion caused abnormal expression of seminal vesicle-associated genes in KO prostates. In summary, these results indicate Foxa1 expression is required for the maintenance of prostatic cellular differentiation.

Prevention and Treatment of Bone Loss in Patients With Nonmetastatic Breast or Prostate Cancer Who Receive Hormonal Ablation Therapy

Hormone ablation therapy is a mainstay in the treatment of breast and prostate cancers. However, aromatase inhibitors (AIs) used in postmenopausal women with breast cancer and androgen-deprivation therapy (ADT) used in men with prostate cancer contribute to substantial bone loss, thereby increasing the risk of osteoporotic fractures. Evidence-based guidelines, therefore, urge oncology practices to screen these patients for bone loss and, if needed, provide treatment to maintain bone health. In addition to lifestyle modification and calcium or vitamin D supplementation, bone protection strategies include treatment with bisphosphonates and denosumab, a monoclonal antibody against RANK ligand. Identification of patients at greater risk for bone loss and fracture and proper interventions can reduce fracture rates. Oncology nurses can play an important role in screening these patients. The purpose of this article is to inform oncology nurses about the effects of cancer treatment on bone health, review current prevention and treatment options for cancer treatment-induced bone loss, and discuss recommendations for identifying high-risk individuals.

Dentatin induces apoptosis in PC3 and LNCaP prostate cancer cells via Bcl- 2, Bcl-xL, Survivin downregulation, Caspase-9, −3/7 activation, and NF-κB inhibition

IntroductionProstate cancer is one of the major causes of deaths in men worldwide with considerable rate due to progressive behavior of androgen-independent cells which become insensitive to hormone ablation therapy. Researchers are in continuous and serious efforts to discover new anticancer drugs as recent therapeutic regimens sometimes ineffective against prostate cancer. Medicinal plants are considered one of the hopeful options providing new bioactive compounds for the treatment of cancer. ObjectiveThis study was established to demonstrate antiproliferative prospect of dentatin, the natural secondary metabolite belongs to coumarins against prostate cancer and to investigate the underlying mechanism of apoptosis. MethodsTreatment with dentatin inhibited cell growth of PC-3 and LNCaP prostate cancer cell lines dose-dependently, whereas it exerted less cytotoxic effects on normal prostate epithelial cell line (RWPE-1). The inhibitory effect of dentatin on prostate cancer cell growth was due to induction of apoptosis as manifested by Annexin V staining and cell shrinkage. Results & DiscussionWe found that dentatin-mediated aggregation of reactive oxygen species (ROS) and downregulated expression levels of antiapoptotic molecules (Bcl-2, Bcl-xL, and Survivin), leading to disruption of mitochondrial membrane potential (MMP), cell membrane permeability, and release of cytochrome c from the mitochondria into the cytosol. These effects were associated with induction of caspase-9, −3/7 activities, and subsequent DNA fragmentation. Moreover, we found that dentatin inhibited TNF-α-induced nuclear translocation of p65, suggesting dentatin as a potential NF-κB inhibitor. ConclusionTherefore, we propose that dentatin may have therapeutic value in prostate cancer treatment worthy of further development.

Challenges in overcoming hormonal resistance in prostate cancer

The treatment landscape for prostate cancer has changed remarkably in the last few years, with several US FDA-approved drugs and a promising pipeline of new agents. The current paradigm of treatment for advanced prostate tumors, which are androgen dependent, is hormone ablation therapy. This can be achieved chemically through LHRH agonists or antagonists, or surgically through orchiectomy. Most tumors respond favorably to this treatment, but eventually the tumor develops a more aggressive castration resistant phenotype. This review will help the reader gain a better understanding of the current paradigm for treatment, efforts to overcome resistance, and the strategies for future development of targeted agents.

Prostatic microenvironment in senescence: fibroblastic growth factors × hormonal imbalance

The aim was to characterize and correlate steroid hormone receptors with the FGF2, FGF7 and FGF8 reactivities in the prostatic epithelium and stroma in senile rats. Fifty male senile rats and 10 young male rats were divided into the young (YNG), the senile groups (SE), the castrated group (CAS), the estrogen-deficient group (ED), the castrated + estrogen group (CASE), and the estrogen-deficient + androgen group (EDTEST). The ventral prostate was submitted to immunohistochemical and Western blotting analyses. The results showed decreased AR and ERβ levels and increased ERα in the senile animals in relation to YNG group. Increased ERα and ERβ reactivities presenting differential localization were characterized in the CASE group compared to the CAS group. Increased FGF2 level was observed in the stroma of the CAS and ED groups in relation to the SE group and in the epithelium of the ED group in relation to the other groups. Increased and differential immunolocalization of FGF7 levels were observed in the CAS, ED and CASE groups. The FGF8 levels showed differential localization in the CAS and ED groups compared to the senile group. The intense hormone ablation was favorable to the autocrine signaling of FGF2 and FGF8. FGF7 could be activated in the androgen-independent via considering the increased FGF7 in the castrated rats. We concluded that hormone ablation in senescence was favorable to activation or/and to fibroblast signaling in the prostatic microenvironment.

A comparative study of glycoproteomes in androgen-sensitive and -independent prostate cancer cell lines

Prostate cancer is one of the most common malignancies in men and is predicted to be the second leading cause of cancer-related deaths. After 6–18 months, hormone ablation treatment results in androgen-independent growth of cancer cells, metastasis and progression. The mechanism of androgen-independent growth of prostatic carcinoma cells is still unknown. Identification of factors that facilitate the transition from androgen-dependent to independent states is crucial in designing future diagnostics and medication strategies. To understand the biochemical meaning of hormone dependency deprivation, glycoproteins enriched profiles were compared between DU145 (hormone non-responding) and LNCaP (hormone responding) prostate cancer cells. These results allow for anticipation on the important role of glycosylation in malignant transformation. Both Tn antigen and complex antennary N-oligosaccharides were recognized. Their occurrence might be involved in the development and progression of tumor, and failure of hormone ablation therapy. Among identified proteins in androgen-sensitive cells nucleolin (P19338) was found that is widely described as apoptosis inhibitor, and also transporter of molecules from the membrane to the cytoplasm or nucleus. In addition, 14-3-3 protein family (P27348, P31946, P61981, P63104, P62258, Q04917, and P31947) was investigated across available databases as it forms stable complexes with glycoproteins. Our studies indicate that isoforms: sigma and eta were found in androgen-dependent prostate cancer cells, while other isoforms were present in androgen non-responding cells. 14-3-3 binding partners are involved in cancer pathogenesis. These findings may contribute to a better understanding of prostate cancer tumorigenesis and to a more efficient prognosis and individual therapy in a future. However, it still remains to be revealed how important those changes are for androgen dependency loss in prostate cancer patients carried out on clinically relevant populations.

Metastatic prostate cancer in transsexual diagnosed after three decades of estrogen therapy.

The incidence of prostate cancer in transsexual patients is very low with only few reported cases. Many years before presenting with prostate cancer, these patients receive hormone ablation as a part of their gender therapy. Their disease is already defined as castrate resistant, and the treatment and follow-up of such patients remains a challenge. We report a case of a male-to-female transgender woman who was diagnosed with metastatic prostate cancer, 31 years post-feminization.

Phenotypic and metabolic aspects of prostatic epithelial cells in aged gerbils after antisteroidal therapy: Turnover in the state of chromatin condensation and androgen-independent cell replacement

The gerbil is a rodent considered a good model for studies of prostatic morphophysiology under different experimental conditions. Studies involving castration and steroidal blockers of aged gerbils showed that the glandular epithelium persists after long-term therapy, preventing the organ atrophy. Thus, the objective of this study was to evaluate the phenotypic characteristics and behavior of prostatic epithelial cells that remained after different periods of hormone ablation in aged gerbils. The identification of elements that influenced the survival of this cell type was performed by morphometric, nuclear phenotypes, ultrastructural and immune histochemical analysis. The most significant responses to treatment, by analyzing morphometric features, were observed during the first three time points (day 1, day 3, and day 7), after which there appeared to be an adjustment of the gland to the hormone ablation. All treatments led to changes in the state of chromatin condensation, DNA methylation pattern and phenotypic changes indicated cell senescence. Additionally, an increase in the basal cells seemed to guarantee self-renewal properties to the epithelium. These data indicate that changes occur at many levels, including gene expression and nuclear architecture in the epithelial cells, when aging and steroidal blockade are associated. These aspects are important when considering castration-resistant prostate cancer, a malignant tumor posing difficult therapeutic intervention.

Impact of denosumab on bone mass in cancer patients

Cancer therapy-induced bone loss (CTIBL) is a form of secondary osteoporosis associated with systemic chemotherapy and hormonal ablation therapy. The monitoring and treatment of CTIBL is an important component of comprehensive cancer care, especially for patients with curable disease and long life expectancies. Whereas oral bisphosphonates remain the most commonly used therapeutic option for CTIBL, additional treatment options may be required for patients who do not respond adequately or are intolerant to bisphosphonates, have renal insufficiency, or are receiving treatment with nephrotoxic medications. For these patients, denosumab, a monoclonal antibody targeting the receptor activator of nuclear factor-κB ligand (RANKL), offers an effective and well-tolerated alternative. Several recent randomized trials have examined the use of denosumab as treatment for CTIBL associated with hormone ablation therapy for breast and prostate cancer. Recent data suggest a possible role for RANKL inhibitors in both chemoprevention and the prevention of cancer recurrence through direct effects on breast tissue and breast cancer stem cells. The outcomes of several international Phase III clinical trials currently underway will help clarify the role of denosumab in patients undergoing cancer therapy.

The ubiquitin ligase Siah2 is revealed as an accomplice of the androgen receptor in castration resistant prostate cancer

The ubiquitin ligase Siah2 is revealed as an accomplice of the androgen receptor in castration resistant prostate cancer

Effect of Ovariohysterectomy at the Time of Tumor Removal in Dogs with Benign Mammary Tumors and Hyperplastic Lesions: A Randomized Controlled Clinical Trial

Nonmalignant mammary tumors (NMT) are common in intact female dogs. Little is known about the clinical significance of these tumors, and the effect of ovariohysterectomy (OHE) on their development. Ovarian hormone ablation through OHE decreases the risk of new tumors and thereby improves long-term prognosis for dogs with NMT. Eighty-four sexually intact bitches with NMT. Dogs were allocated to undergo OHE (n = 42) or not (n = 42) at the time of NMT removal in a randomized clinical trial. Tumor diagnosis was confirmed histologically in all subjects. Information about new tumor development was collected via follow-up phone calls and recheck examinations. Separate survival analyses were performed with the endpoints new tumor development and death. Cause of death was classified as related or unrelated to mammary tumor. In addition to OHE status, the influence of age, body weight, breed, tumor size, tumor number, tumor duration, type of surgery, and tumor histology was investigated. New mammary tumor(s) developed in 27 of 42 (64%) intact dogs and 15 of 42 (36%) ovariohysterectomized dogs (hazard ratio 0.47, P = .022). Nine of the 42 dogs (21%) which developed new tumors were euthanized because of mammary tumor. Survival was not significantly different between the 2 treatment groups. In the intact group, nine dogs subsequently developed ovarian-uterine diseases. Ovariohysterectomy performed at the time of mammary tumor excision reduced the risk of new tumors by about 50% among dogs with NMT. Survival was not significantly affected. Adjuvant OHE should be considered in adult dogs with mammary tumors.

A Low Dietary Ratio of Omega-6 to Omega-3 Fatty Acids May Delay Progression of Prostate Cancer

Prostate cancer (PCa) is the second leading cause of cancer-related deaths in men. Studies show that consumption of polyunsaturated fatty acids (PUFA) modulates the development and progression of prostate cancer. High amounts of omega-6 fatty acids have been linked with increased prostate cancer risk, whereas omega-3 fatty acids have been shown to inhibit PCa growth. However, because omega-3 and omega-6 are both essential fatty acids and part of a complete diet, it is more relevant to determine the ideal ratio of the two that would allow patients to benefit from the therapeutic properties of omega-3 fatty acids. LNCaP prostate cancer cells were treated with dietary-based ratios of omega-6 to omega-3 fatty acids under hormone-deprivation conditions, and effects on various cellular processes were determined. A low omega-6 to omega-3 PUFA ratio can delay the progression of cells toward castration-resistance by suppressing pathways involved in prostate cancer progression, such as the Akt/mTOR/NFκB axis. It also suppresses the expression of cyclin D1, and activation of caspase-3 and annexin V staining shows induction of proapoptotic events. Taken together, our data demonstrates that maintaining a low omega-6 to omega-3 fatty acids ratio can enhance efficacy of hormone ablation therapy.

Parathyroid hormone ablation alters erythrocyte parameters that are rescued by calcium‐sensing receptor gene deletion

The mechanisms by which parathyroid hormone (PTH) produces anemia are unclear. Parathyroid hormone secretion is regulated by the extracellular Ca2+ -sensing receptor. We investigated the effects of ablating PTH on hematological indices and erythrocytes volume regulation in wild-type, PTH-null, and Ca2+ -sensing receptor-null/PTH-null mice. The erythrocyte parameters were measured in whole mouse blood, and volume regulatory systems were determined by plasma membrane K+ fluxes, and osmotic fragility was measured by hemoglobin determination at varying osmolarities. We observed that the absence of PTH significantly increases mean erythrocyte volume and reticulocyte counts, while decreasing erythrocyte counts, hemoglobin, hematocrit, and mean corpuscular hemoglobin concentration. These changes were accompanied by increases in erythrocyte cation content, a denser cell population, and increased K+ permeability, which were in part mediated by activation of the K+ /Cl- cotransporter and Gardos channel. In addition we observed that erythrocyte osmotic fragility in PTH-null compared with wild-type mice was enhanced. When Ca2+ -sensing receptor gene was deleted on the background of PTH-null mice, we observed that several of the alterations in erythrocyte parameters of PTH-null mice were largely rescued, particularly those related to erythrocyte volume, K+ fluxes and osmotic fragility, and became similar to those observed in wild-type mice. Our results demonstrate that Ca2+ -sensing receptor and parathyroid hormone are functionally coupled to maintain erythrocyte homeostasis.

A phase II trial of androgen deprivation therapy (ADT) plus chemotherapy as initial treatment for local failures or advanced prostate cancer

Long-term hormonal ablation in prostate cancer is associated with decreased overall health and quality of life. Few reports emphasized the role of chemotherapy in the management of early stage prostate cancer. This study analyzed the safety and efficacy of androgen deprivation therapy (ADT) plus chemotherapy as initial treatment for patients identified as local failures or not eligible for prostatectomy or radiation therapy due to advanced disease presentation. Enrolled patients received ADT in the form of leuprolide every 12 weeks for 24 months with bicalutamide initiating after the completion of chemotherapy. Chemotherapy consisted of ketoconazole and doxorubicin for weeks 1, 3, and 5 and estramustine and docetaxel and for weeks 2, 4 and 6. During weeks 7 and 8, no treatment was received. Forty-six patients were enrolled, and forty-five patients were evaluable. Median progression-free survival (PFS) was 23.4 months. Median overall survival (OS) was 53.7 months. Out of 45 patients with measurable disease, 22 patients had an objective response: 9 patients achieved a complete response; 2 patients achieved a partial response; 10 patients achieved stable disease. Frequent grade 3 adverse events included elevated ALT (17 %), hypokalemia (13 %), and hypophosphatemia (13 %). Grade 4 adverse events were rare and included low bicarbonate (2 %), hypokalemia (2 %), leukocytopenia (2 %), and neutropenia (2 %). The treatment demonstrated clinical benefit in all patient subsets with minimal reversible treatment-related adverse events. Subgroup analysis suggests that having prior local therapy resulted in greater PFS and OS.

Abstract 843: Inhibition of AKT signaling promotes FOXO3a-dependent apoptosis in castration-resistant prostate cancer cells.

Abstract Treatment for aggressive prostate cancers involves hormonal ablation therapy, radical prostatectomy, radiation therapy, chemotherapy or in combination. Despite their initial sensitivity to these treatments, prostate cancer eventually progresses to castration -resistant prostate cancer (CRPC), which is both aggressive and refractory to current therapeutic modalities. Hence, CRPC demands the identification of novel targeted therapies with minimal side effects. We identified Withaferin-A (WA) a major bioactive compound derived from the medicinal plant, Withania somnifera, is extensively used in Asian herbal medicines to treat a variety of ailments, including cancer. Earlier, we reported that WA induced the pro-apoptotic gene, prostate apoptosis response-4 (Par-4) and apoptosis in CRPC cells. These results encouraged us to determine the mechanism of action of WA on CRPC cells. It is known that activated AKT negatively regulates forkhead transcription factor class O family protein (FOXO3a) that regulates genes involved with tumorigenesis, cell cycle arrest or apoptosis. In the present study, we found that FOXO3a is an upstream of Par-4 signaling which transactivates Par-4 function in CRPC cells. Inhibition of AKT activation by WA facilitates nuclear translocation of FOXO3a which in turn activates Par-4 mediated apoptosis in CRPC cells. Our confocal and immuno-precipitation studies confirmed that upon activation. FOXO3a and Par-4 were co-localized in the nucleus. Similar results were found with overexpression of FOXO3a showing transactivation of Par-4 and growth arrest in CRPC cells. Treatment of actinomycin-D or cyclohexmide along with WA, confirmed that FOXO3a regulation on Par-4 function in CRPC cells. On contrary, inhibition of FOXO3a by siRNA resulted in down regulation of Par-4 and apoptosis by WA in CRPC cells suggesting FOXO3a activation is necessary for the induction of Par-4 mediated apoptosis. Promoter bashing studies suggest a direct interaction of FOXO3a with Par-4 promoter; a sequential deletion of FOXO3a DNA binding sites in Par-4 promoter fails to induce Par-4 activation upon WA treatment in CRPC cells. Overall, our studies conclude that Par-4 is a target of FOXO3a, and Par-4 activation is required for induction of apoptosis in CRPC cells. Activation of FOXO3a is an attractive target for the treatment of CRPC and molecules such as WA can be explored further for the treatment of CRPC. Citation Format: Trinath P. Das, Chendil Damodaran. Inhibition of AKT signaling promotes FOXO3a-dependent apoptosis in castration-resistant prostate cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 843. doi:10.1158/1538-7445.AM2013-843

Abstract 3181: The genomic evolution of prostate cancer under the selective pressure of anti-androgen therapy.

Abstract Background: The implementation of novel technologies such as array comparative genomic hybridization (aCGH) and next-generation sequencing has led to a deeper understanding of the genomic nature of cancer. However, these analyses have classically been done without respecting intra-tumor heterogeneity. Here, we applied a methodology that allows us analyzing the genomic profile of distinct tumor populations from individual tumors and their clonal evolution during the progression to castration-resistant disease. Methods: Matched pre- and post- hormone treated fresh frozen and/or formalin fixed prostate cancer samples were selected from our biobank. Clonal tumor populations were flow-sorted according to their nuclear DNA content. Sorted tumor populations were subjected to whole genome CGH and to full exome sequencing analyses by the use of Agilent SurePrint 2x400k microarrays and the SureSelect All Exon Kit, respectively. Results: The genomic analyses of the tumor samples underscore the presence of significant intra-tumoral heterogeneity. The analysis of matched tumor specimens allowed us to identify two particular patterns of tumor evolution during the progression after treatment: First, a more parallel pattern of tumor evolution, in which the ancestor population is breeding multiple aneuploid tumor clones. In this case, only the 2N ancestor population is able to withstand therapy by the acquisition of few specific genomic aberrations whereas the aneuploid populations are eradicated. Second, a more sequential pattern of tumor evolution with a tumor population that evolves out of a continuous line of clones. This population shows increasing signs of genomic instability over time, with a punctual event of chromothripsis (a massive destruction and rearrangement of chromosomal structures) resulting in castration-resistant clonal tumor populations. Conclusions: Genomic profiling of distinct clonal tumor populations during prostate cancer progression allows for analysis of intra-tumoral heterogeneity and the underlying clonal evolution. Importantly, this approach identifies genomic aberrations that were selected for under the pressure of hormone ablation therapy. Citation Format: Joël R. Gsponer, Tanja Dietsche, Alexander Rufle, Elisabeth Lenkiewicz, Tobias Zellweger, Alexander Bachmann, Daniel D. Von Hoff, M T. Barrett, Cyrill Rentsch, Christian Ruiz, Lukas Bubendorf. The genomic evolution of prostate cancer under the selective pressure of anti-androgen therapy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3181. doi:10.1158/1538-7445.AM2013-3181