Prostate-derived Ets Factor Research Articles

Molecular Docking and Dynamics Simulation study for Anticancer Phytoconstituents inhibiting breast cancer

The main challenge in the fight against breast cancer (BC) is to create new medications that are more selective for cancer cells and have fewer adverse effects. SPDEF (Sam pointed domain containing ETS transcription factor) is a prostate-derived ETS factor that maintains homeostasis, differentiation of epithelial tissues and heritable alterations in cancer. Previously, SPDEF has been shown to be associated with BC subtypes and is found to be down-regulated in invasive breast cancer cell lines which is supportive of its role in tumor suppression. In the current study, SPDEF protein was used as a potential breast cancer therapeutic target. A total of fifteen phytoconstituents were evaluated as potential drug ligands against SPDEF using various in silico approaches. Genistein, allicin, 2-hydroxychalcone and ajoene were free from any of the predicted toxicological endpoints. As per toxicological endpoints prediction study, the median lethal dosage (LD50) values for these phytoconstituents varied from 159 to 3919 mg/Kg. Our results indicate that out of fifteen, three phytoconstituents silibinin (-7.7 kcal/mol), codonolactone (-6.1 kcal/mol) and genistein (-6.1 kcal/mol), showing the lowest binding energies, had more significant inhibitory effects against SPDEF protein. We selected these three phytoconstituents on the basis of binding scores for molecular dynamic simulations at 200 ns to study their protein-ligand complex stability. Out of the three, silibinin-receptor complex had more stability. The present analysis shows that silibinin could be a potential therapeutic compound against breast cancer as assessed by its binding interaction and stability analyses against SPDEF.

Abstract 1471: Over-expression of WW domain containing transcription regulator 1 (TAZ/WWTR1) in prostate cancer and its modulation by prostate-derived ETS factor (PDEF)

Abstract Objective: WW domain containing transcription regulator 1 (TAZ/WWTR1), one of the two downstream effectors of the Hippo pathway, is known to regulate cancer cell proliferation, migration and apoptosis by acting as a transcriptional co-activator. Recently, we described altered expression of yes-associated protein (YAP1) (a paralog of TAZ) in prostate cancer. However, the expression and function of TAZ and its regulation in prostate cancer is not well characterized. In the present study, we profiled expression patterns of TAZ in clinical data sets of PCa and evaluated the effects of PDEF on TAZ phosphorylation in prostate cancer (PCa) cells in culture. Material & Method: We analyzed the publicly available PCa datasets through Ualcan and c-Bioportal webservers. We transfected prostate cancer PC3 cells with PDEF or respective vector control. Protein levels of TAZ were analyzed by western blotting. Global changes in gene expression were analyzed using Affymetrix arrays followed by Gene Set Enrichment analysis. Results: Our analysis of publicly available PCa patient data in TCGA dataset, revealed a significant increase in TAZ mRNA levels in prostate cancer tissues as compared to normal prostate tissues (p=4.95E-08). Furthermore, we also found a significant gradual increase in TAZ mRNA expression during disease progression and metastasis. Our analysis of data sets in c-Bio portal revealed that patients with neuroendocrine PCa harbor much higher levels of TAZ mRNA as compared to CRPC phenotype. We also observed a negative correlation between PDEF and TAZ expression in CRPC/NEPC data set. We observed that the PC3 cells transfected with PDEF (PDEF-PC3) showed an increased phospho-TAZ as compared to the respective PC3 vector control (VC-PC3) suggesting that PDEF plays a critical role in modulating TAZ activity an important effector in Hippo signaling. Conclusions: These results provide first direct demonstration of elevated expression of TAZ in PCa, suggesting potential role of TAZ in prostate cancer. We also show for the first time increased TAZ phosphorylation in PCa cells by PDEF. Taken together with our recent work, our data suggest that PDEF modulates Hippo signaling by targeting both YAP1 and TAZ in PCa. Citation Format: Praveen K. Jaiswal, Suman Mohajan, Sweaty Koul, Hari K. Koul. Over-expression of WW domain containing transcription regulator 1 (TAZ/WWTR1) in prostate cancer and its modulation by prostate-derived ETS factor (PDEF) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1471.

Retraction Note to: Loss of PDEF, a prostate-derived Ets factor is associated with aggressive phenotype of prostate cancer: Regulation of MMP 9 by PDEF

Prostate-derived Ets factor (PDEF) is expressed in tissues of high epithelial content including prostate, although its precise function has not been fully established. Conventional therapies produce a high rate of cure for patients with localized prostate cancer, but there is, at present, no effective treatment for intervention in metastatic prostate cancer. These facts underline the need to develop new approaches for early diagnosis of aggressive prostate cancer patients, and mechanism based anti-metastasis therapies that will improve the outlook for hormone-refractory prostate cancer. In this study we evaluated role of prostate-derived Ets factor (PDEF) in prostate cancer. We observed decreased PDEF expression in prostate cancer cell lines correlated with increased aggressive phenotype, and complete loss of PDEF protein in metastatic prostate cancer cell lines. Loss of PDEF expression was confirmed in high Gleason Grade prostate cancer samples by immuno-histochemical methods. Reintroduction of PDEF profoundly affected cell behavior leading to less invasive phenotypes in three dimensional cultures. In addition, PDEF expressing cells had altered cell morphology, decreased FAK phosphorylation and decreased colony formation, cell migration, and cellular invasiveness. In contrast PDEF knockdown resulted in increased migration and invasion as well as clonogenic activity. Our results also demonstrated that PDEF downregulated MMP9 promoter activity, suppressed MMP9 mRNA expression, and resulted in loss of MMP9 activity in prostate cancer cells. These results suggested that loss of PDEF might be associated with increased MMP9 expression and activity in aggressive prostate cancer. To confirm results we investigated MMP9 expression in clinical samples of prostate cancer. Results of these studies show increased MMP9 expression correlated with advanced Gleason grade. Taken together our results demonstrate decreased PDEF expression and increased MMP9 expression during the transition to aggressive prostate cancer. These studies demonstrate for the first time negative regulation of MMP9 expression by PDEF, and that PDEF expression was lost in aggressive prostate cancer and was inversely associated with MMP9 expression in clinical samples of prostate cancer. Based on these exciting results, we propose that loss of PDEF along with increased MMP9 expression should serve as novel markers for early detection of aggressive prostate cancer.

SPDEF targets EMT pathway to inhibit cell migration and invasion in triple‐negative breast cancer

Background Current treatments against triple-negative breast cancer (TNBC) are ineffective due to the high rate of metastasis and therapy resistance. There is, therefore, a pressing need for novel and efficacious therapies against TNBC. The basal-like TNBC has a poor prognosis and a high metastasis rate compared to the luminal-like breast cancer subtypes. Here, set to determine the role of Sam Pointed Domain Ets Transcription Factor also known as Prostate-Derived Ets Factor (SPDEF/PDEF), in TNBC. Methods Clinical data were extracted from the METABRIC breast cancer project, hosted at the TCGA database. MDA-MB-231 and MDA 231-LM2-4175 cells were stably transfected with PDEF/control pBABE retroviral vectors. Cell migration/invasion assays were done to explore the effects of PDEF expression on the motility of TNBC cells. Proliferation was measured under 2D and 3D culture conditions. qRT-PCR and immunoblot were performed to visualize gene and protein expression. Data were graphed and analyzed using Graph Pad Prism Software 8 using one-way ANOVA and the unpaired two-tailed Student's t-test. All data were evaluated in triplicate against vector control cells. Results Basal gene and protein expression screening revealed that the expression of PDEF is significantly lower in highly metastatic breast cancer cells compared to the non-metastatic ones. Data analysis from clinical breast cancer METABRIC cohort revealed the loss of PDEF is associated with tumor metastasis, tumor grade, and poor patient survival. PDEF is lost in highly metastatic and therapy resistant TNBC cells. Re-expression of PDEF diminished cell migration and invasion in TNBC cells. Decreased migration and invasion in response to PDEF was not a result of decreased cell growth and proliferation or increased cell death but a result of suppression of EMT markers in TNBC cells. Conclusions PDEF expression inhibits cell migration and invasion partially by down-regulating EMT-related protein markers, suggesting a critical role for PDEF in suppressing TNBC cell metastasis.

Double Agent: SPDEF Gene with Both Oncogenic and Tumor-Suppressor Functions in Breast Cancer.

The dichotomy of cancer-regulatory genes into “oncogenes (OCGs)” and “tumor-suppressor genes (TSGs)” has greatly helped us in learning molecular details of tumor biology. SPDEF, known as the prostate-derived ETS factor, is reported to play a pivotal role in normal cell development and survival, which has also been endowed with dual characteristics in cancers. Breast cancer (BC) is a highly heterogeneous disease which becomes the leading reason for cancer-related fatality among women worldwide. The involvement of SPDEF in many aspects of BC has been postulated, whereas the mechanism governing the regulation of the pro- and anti-oncogenic activities of SPDEF in BC state remains poorly defined. In this review, we summarized SPDEF as the double agent involving in expression profiles, the regulatory mechanism in BC progression, as well as the role in diagnosis, treatment and prognosis of BC. The understanding of SPDEF duality has contributed to gain insight into the tumor biology and also add a new dimension to the new therapy targets for BC.

Prostate-Derived ETS Factor (PDEF) Modulates Yes Associated Protein 1 (YAP1) in Prostate Cancer Cells: A Potential Cross-Talk between PDEF and Hippo Signaling.

PDEF (prostate-derived ETS factor, also known as SAM-pointed domain containing ETS transcription factor (SPDEF)) is expressed in luminal epithelial cells of the prostate gland and associates with luminal phenotype. The Hippo pathway regulates cell growth/proliferation, cellular homeostasis, and organ development by modulating phosphorylation of its downstream effectors. In previous studies, we observed decreased levels of PDEF during prostate cancer progression. In the present study, we evaluated the effects of the expression of PDEF on total/phosphoprotein levels of YAP1 (a downstream effector of the Hippo pathway). We observed that the PC3 and DU145 cells transfected with PDEF (PDEF-PC3 and PDEF-DU145) showed an increased phospho-YAP1 (Ser127) and total YAP1 levels as compared to the respective PC3 vector control (VC-PC3) and DU145 vector control cells (VC-DU145). We also observed an increased cytoplasmic YAP1 levels in PDEF-PC3 cells as compared to VC-PC3 cells. Moreover, our gene set enrichment analysis (GSEA) of mRNA expression in PDEF-PC3 and VC-PC3 cells revealed that PDEF resulted in inhibition of YAP1 target genes, directly demonstrating that PDEF plays a critical role in modulating YAP1 activity, and by extension in the regulation of the Hippo pathway. We also observed a decrease in YAP1 mRNA levels in prostate cancer tissues as compared to normal prostate tissues. Our analysis of multiple publicly available clinical cohorts revealed a gradual decrease in YAP1 mRNA expression during prostate cancer progression and metastasis. This decrease was similar to the decrease in PDEF levels, which we had reported earlier, and we observed a direct correlation between PDEF and YAP1 expression in CRPC data set. To the best of our knowledge, these results provide the first demonstration of inhibiting YAP1 activity by PDEF in any system and suggest a cross-talk between PDEF and the Hippo signaling pathway.

A high AR:ERα or PDEF:ERα ratio predicts a sub-optimal response to tamoxifen therapy in ERα-positive breast cancer.

Approximately 30% oestrogen receptor alpha (ERα)-positive breast cancer (BC) patients exhibit intrinsic or recurrent resistance to adjuvant endocrine therapy with tamoxifen. The androgen receptor (AR) is expressed in about 90% of ERα-positive patients, with particularly high expression in tamoxifen-resistant tumours. Prostate-derived Ets factor (PDEF), which is a co-regulator of AR, plays a role in tamoxifen resistance in ERα-positive BC. The purpose of this research was to analyse the potential roles of AR, PDEF and ERα levels in the response to tamoxifen resistance in ERα-positive BC. The nuclear AR:ERα and PDEF:ERα ratios were examined immunohistochemically in a cohort of 225 ERα-positive pre-menopausal BC patients who had received adjuvant tamoxifen therapy. For both AR:ERα and PDEF:ERα ratios, the optimal cutoff value was 2.0. Patients receiving adjuvant tamoxifen treatment who had a high AR:ERα (≥ 2.0) (HR = 3.90) or PDEF:ERα ratio (≥ 2.0) (HR = 2.77) had a beyond twofold increased risk of failure. Both the AR:ERα ratio (P = 0.001) and PDEF:ERα ratio (P = 0.002) were independently associated with the risk of tamoxifen treatment failure. Furthermore, both a high ratio of AR:ERα (≥ 2.0) and PDEF:ERα (≥ 2.0) were associated with shorter disease-free survival (DFS) and shorter disease-specific survival (DSS). In addition, both the AR:ERα ratio and PDEF:ERα ratio were independent predictors of DFS (both P < 0.0001) and DSS (P = 0.001 and P < 0.0001, respectively). AR:ERα and PDEF:ERα ratios are independent predictors of the response to conventional ERα-directed tamoxifen endocrine therapy.

Abstract 5287: Prostate-derived Etsfactor modulates AR-mediated gene expression and promotes luminal differentiation

Abstract Introduction: Transcription regulation, governed by the presence of transcription factors and the accessibility of regulatory elements such as enhancers is crucial in restricting lineage plasticity. Deregulated expression of differentiation-related transcription factors leads to cancer progression and poor prognosis. Prostate-derived ETS factor (PDEF) is one of the cell identity-related transcription factors characterized by the abundance of H3K27ac near its genomic locus. Highly expressed in prostate luminal cells, PDEF has been shown to promote the transcription of PSA in collaboration with AR. Our previous studies showed loss of PDEF is associated with higher Gleason score and tumor metastasis through MMP9 and Twist1. However, the role of PDEF, as a transcription factor, remains poorly understood. In this study, we evaluated the effects of PDEF on modulation of AR cistrome and luminal/epithelial differentiation. Methods: TCGA data were extracted from cBioportal and analyzed using R. Gene set enrichment analysis (GSEA) was performed using default settings and gene sets were downloaded from MySigDB. Genomic coverage analysis was performed using SeqPlots. ChIP-seq analysis was performed using GALAXY. PC3 cells were grown in DMEM/F12 medium and retroviral expression was used to generate cells with stable PDEF expression. ChIP experiments were performed using Chromatrap ChIP-seq kit followed by standard qPCR with SYBR-Green. Gene track was visualized with IGV. Results: Despite the oncogenic role of AR signaling, it plays a pivotal part in prostate luminal differentiation. We observed that prostate cancer progression is associated with loss of PDEF accompanied by a transcription switch from canonical AR targets to non-canonical in TCGA database. Moreover, AR genomic coverage in prostate luminal cell-specific enhancer regions is decreased in tumor tissues compared with the paired adjacent normal tissue. Stable-expression of PDEF in PC3 cells restored the expression of canonical AR targets as well as the enhancer pattern similar to LNCaP cells. PDEF ChIP-seq analysis of multiple cell lines revealed that PDEF co-localize with H3K4me1. ChIP-qPCR confirmed that PDEF co-localized with AR at the PSA enhancer region. We hypothesize that PDEF is critical for maintaining prostate luminal specific enhancers. Expressing PDEF in LNCaP-abl cells also increased the transcription of canonical AR targets and inhibited the transcription of non-canonical AR targets. Independent of AR, we discovered that PDEF binds to the promoter region of CK18. Moreover, a positive correlation was observed between PDEF and CK18 in cell culture and prostate cancer samples in the TCGA database. Conclusion: These results show that PDEF plays an important role in the maintenance of canonical AR signature and luminal cell differentiation in prostate cancer in-part by rewiring the transcriptional program. Citation Format: Fengtian Wang, Hari K. Koul. Prostate-derived Etsfactor modulates AR-mediated gene expression and promotes luminal differentiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5287.

CRISPR/Cas9-mediated knockout of the PDEF gene inhibits migration and invasion of human gastric cancer AGS cells

Gastric cancer is one of the most common malignant tumors worldwide and has the second highest incidence and mortality rate among malignant tumors in China. Prostate-derived Ets factor (PDEF) is a member of the Ets family of transcription factors. Although PDEF plays an important role in tumorigenesis, its biological function in gastric cancer is still unclear. Here, we evaluated PDEF expression in 30 cases of human gastric carcinoma and the corresponding peritumoral tissues, using immunohistochemistry and immunofluorescence. Significantly higher levels of PDEF were detected in tumors compared to peritumoral tissues. We then investigated PDEF expression in the gastric cancer cell lines SGC and AGS and the normal gastric epithelial cell line GES; The CRISPR/Cas9 genome-editing system was used to knockout PDEF in AGS cells as a model for gastric cancer. Cell proliferation, apoptosis, migration, and invasion of PDEF-knockout AGS cells were evaluated using CCK-8, flow cytometry, scratch wound, and transwell assays, respectively. The results illustrated that PDEF-knockout inhibited AGS cell proliferation, migration, and invasion. Taken together, the results imply that PDEF plays important roles in the proliferation, migration, and invasion of AGS cells and may serve as a new treatment target in gastric cancer.

AR\u2013PDEF pathway promotes tumour proliferation and upregulates MYC-mediated gene transcription by promoting MAD1 degradation in ER-negative breast cancer

BackgroundAndrogen receptor (AR) is expressed in 60%~ 70% oestrogen receptor (ER)-negative breast cancer (BC) cases and promotes the growth of this cancer subtype. Expression of prostate-derived Ets factor (PDEF), a transcription factor, is highly restricted to epithelial cells in hormone-regulated tissues. MYC and its negative regulator MAD1 play an important role in BC progression. Previously, we found that PDEF expression is strongly correlated with AR expression. However, the relationship between AR and PDEF and the function of PDEF in ER-negative BC proliferation are unclear.MethodsAR and PDEF expression in ER-negative BC tissues and cell lines was determined by performing immunohistochemistry or western blotting. Protein expression levels and location were analysed by performing western blotting, RT-qPCR and immunofluorescence staining. Co-immunoprecipitation and chromatin immunoprecipitation assays were performed to validate the regulation of AR–PDEF–MAD1–MYC axis. Moreover, the effect of AR and PDEF on BC progression was investigated both in vitro and in vivo.ResultsWe found that PDEF was overexpressed in ER-negative BC tissues and cell lines and appeared to function as an oncogene. PDEF expression levels were strongly correlated with AR expression in ER-negative BC, and PDEF transcription was positively regulated by AR. PDEF upregulated MYC-mediated gene transcription by promoting MAD1 degradation in ER-negative BC. Finally, we found that compared with the inhibition of AR expression alone, simultaneous inhibition of AR and PDEF expression further suppressed tumour proliferation both in vitro and in vivo.ConclusionsOur data highlight the role of the AR–PDEF–MAD1–MYC axis in BC progression and suggest that PDEF can be used as a new clinical therapeutic target for treating ER-negative BC.

Prostate-Derived Ets Factor (PDEF) Inhibits Metastasis by Inducing Epithelial/Luminal Phenotype in Prostate Cancer Cells.

Metastasis is the primary cause of prostate cancer morbidity and mortality. Our previous studies revealed that Sam pointed domain ETS transcription factor, a.k.a. prostate-derived ETS factor (SPDEF/PDEF), inhibits prostate cancer metastasis. However, the mechanism is still unclear. In this study, using microarray and gene set enrichment analysis, we discovered that PDEF upregulated epithelial/luminal differentiation-related genes while it suppressed stemness and epithelial-to-mesenchymal transition-related genes, especially Twist1. We also observed loss of PDEF and gain of Twist1 expression during prostate cancer progression in the TRAMP mouse model. Moreover, Twist1 knockdown resulted in upregulation of PDEF expression, suggesting a reciprocal regulation between PDEF and Twist1. Mechanistically, our ChIP-seq analysis revealed that PDEF directly regulated cytokeratin 18 (CK18) transcription through the GGAT motif within its putative promoter region. CK18 knockdown resulted in increased expression of Twist1, suggesting that PDEF regulated Twist1 in part via CK18. Our analysis of multiple clinical prostate cancer cohorts revealed an inverse relationship between PDEF expression and tumor grade, tumor metastasis, and poor patient survival. Furthermore, a two-gene signature of low PDEF and high Twist1 can better predict poor survival in prostate cancer patients than either gene alone. Collectively, our findings demonstrate PDEF inhibits prostate tumor progression, in part, by directly regulating transcription of CK18, and that PDEF/Twist1 expression could help distinguish between lethal and indolent prostate cancer.Implications: This study reports the novel findings that PDEF suppresses Twist1 partly via CK18 and that PDEF/Twist1 could help distinguish between lethal and indolent prostate cancer.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/16/9/1430/F1.large.jpg Mol Cancer Res; 16(9); 1430-40. ©2018 AACR.

Clinical significance of PDEF factor expression and its relation to androgen receptor in ER- breast cancer.

The mechanism of androgen receptor (AR) promoting tumour growth in oestrogen receptor-negative (ER- ) breast cancer (BC) is undetermined. Prostate-derived ETS factor (PDEF) is highly restricted to the hormone-regulated tissues of epithelial cells, such as those in the prostate, breast and other tissues. It has been demonstrated that PDEF expression is associated with AR in prostate cancer. In this research, we aimed to investigate the relationship between PDEF and AR in ER- BC. We immunohistochemically evaluated the correlation between PDEF and AR expression in 246 cases of ER- invasive BC, and investigated their relationship in ER- BC cell lines. The expression of PDEF was associated with the positive expression of AR (P<0.001) and a worse survival rate (P=0.006). PDEF+ tumours were significantly more often AR+ (P<0.001). AR and PDEF were more often co-expressed and the series of AR+ PDEF+ (126 of 246, 51.2%) had a poor survival rate (P=0.046). In Cox models, PDEF expression (P=0.028) was an independent predictor for overall survival (OS). At the cellular protein and mRNA levels, our experiments also showed a statistically significant positive correlation between PDEF and AR, and that PDEF may be regulated by AR. PDEF is associated with markers of bad prognosis, supporting its role as a growth promoter in ER- BC. Our findings also provide evidence that PDEF is strongly correlated with AR expression in ER- breast cancer; it may be a downstream target gene of AR and a potential prognostic factor in ER- BC.

Abstract 1502: PDEF inhibits prostate cancer progression by promoting luminal differentiation

Abstract Background: The emergence of metastatic castration-resistant prostate cancer (PCa) is accompanied by the loss of prostate luminal cell identity. Cell identity is defined by key transcription factors by association with enhancer and super-enhancer elements. Our previous studies have shown that Sam Pointed Domain Ets Transcription Factor a.k.a. Prostate-Derived Ets Factor (SPDEF/PDEF), inhibits tumor metastasis in vivo. Recently, PDEF has been reported as one of the super enhancer related transcription factors in the luminal PCa cell line LNCaP and observed to be highly expressed in prostate luminal cells. We propose that PDEF functions as a putative tumor metastasis suppressor and inhibits tumor progression by restoring luminal cell identity. The present study was designed to investigate the role of PDEF in metastatic PCa progression. Methods: PC3 and DU145 cells were stably transfected with PDEF/control pBABE retroviral vectors. Global gene expression changes were probed using Affymetrix microarray. Microarray was analyzed with GSEA. qRT-PCR was performed to confirm the differential gene expression profile and immunohistochemistry, immunofluorescence and immunoblot were performed to visualize protein expression. ChIP-seq data were extracted from SRP002475 and aligned with Bowtie. Peaks were identified by MACS2. Clinical data were extracted from GSE16560, GSE21034 and TCGA database. Statistical analysis was performed with GraphPad and R. Results: Analysis of our microarray studies revealed that PDEF expression resulted in the negative enrichment of metastasis-related gene sets and the positive enrichment of gene sets involved in luminal differentiation. Especially, PDEF restores canonical AR signaling in PC3 cells. Confirmed with qPCR, IB and IF, PDEF also inhibits the expression of neuroendocrine-related genes, stemness-related genes while promoting the expression of prostate luminal differentiation-related genes. Furthermore, PDEF ChIP-seq analysis revealed a novel PDEF binding site at the putative promoter region of prostate luminal cell marker cytokeratin 18 while no significant peaks were identified within the regulatory elements of EMT related transcription factors. Our data suggest that PDEF promotes the expression of cytokeratin 18 in vitro and in vivo. Knockdown of cytokeratin 18 by siRNA increases the expression of Twist1 while decreases the expression of E-Cadherin while PDEF expression level is not affected. Moreover, data analysis from multiple clinical prostate cancer cohorts suggests the loss of PDEF is associated with tumor metastasis, tumor progression, and poor survival. Conclusions: PDEF expression leads to luminal differentiation phenotype in advanced prostate cancer cells. PDEF inhibits cell migration and metastasis in part by down-regulating EMT related transcription factors in part through directly promoting the expression of cytokeratin 18. Citation Format: Fengtian Wang, Sweaty Koul, Hari K. Koul. PDEF inhibits prostate cancer progression by promoting luminal differentiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1502.

Abstract 3525: PDEF promote prostate cancer luminal/epithelial differentiation and inhibit tumor progression

Abstract Conventional therapies produce a high rate of cure for patients with localized prostate cancer (PCa), but there is no effective treatment for castration resistant metastatic PCa. Transcription factors by association with enhancer and super-enhancer elements are key drivers of cell identity. Our previous studies have shown that Sam Pointed Domain Ets Transcription Factor a.k.a. Prostate Derived Ets Factor (SPDEF/PDEF), inhibits cell migration, invasion and clonogenic activity in PCa cells and there is a graded loss of PDEF with increasing Gleason Score in PCa patient samples. PDEF has been reported to be one of the cell identity transcription factors in LNCaP cells. We proposed that PDEF functions as a putative tumor metastasis suppressor. Others have shown an increase in Twist1, a bHLH transcription factor, was positively correlated with Gleason Grading. Present study was designed to investigate the role of PDEF and interplay between PDEF and Twist1 in PCa. PC3 cells were stably transfected with PDEF/control PABABE vectors. Gene expression changes were monitored by Affymetrix microarray. Microarray was analyzed with GSEA. qRT-PCR was performed to confirm gene expression and IHC, IF and IB analysis were performed to visualize protein expression. Chip-seq data (SRP002475) was aligned with Bowtie. Peaks were identified by MACS and visualized using IGB. PDEF/Twist1 expression data was extracted from GSE16560. GraphPad was used to generate KM survival analysis of PCa patients. Our results show that PDEF expression is limited to epithelial/luminal cells of the prostatic glands. We observed that expression of Twist1 was down regulated in PC3 cells following PDEF expression. Analysis of gene expression data from our microarray studies revealed that PDEF re-expression was associated with negative enrichment of gene sets involved with cell migration and positive enriched of gene sets involved with epithelial/luminal differentiation. Chip-seq analysis revealed a binding of PDEF to KRT8/18 promoter region. These data suggest that PDEF inhibits core metastasis related genes through promoting a program of luminal/epithelial differentiation. In clinical samples of PCa, expression of PDEF was inversely associated, while expression of Twist1 was positively associated with Gleason grade. PDEF and Twist1 was able to predict patient survival, moreover integrated PDEF and Twist1 expression was able to better predict PCa patient survival as compared to PDEF or Twist1 alone. PDEF inhibits cell migration and metastasis in part by down-regulating Twist1 level and promoting luminal/epithelial differentiation. Loss of PDEF combined with gain of Twist1 expression may serve as a potential biomarker set for distinguishing lethal PCa from an indolent disease. Additional studies are underway to gain further insights into the role of PDEF in PCa progression and metastasis. Acknowledgement: FWCC support and Chair commitment funds (Koul H). Citation Format: Fengtian Wang, Sweaty Koul, Prakash Srinivasan Timiri Shanmugam, Qin Dong, Hari K. Koul. PDEF promote prostate cancer luminal/epithelial differentiation and inhibit tumor progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3525. doi:10.1158/1538-7445.AM2017-3525

Prostate-derived Ets factor, an oncogenic driver in breast cancer.

Prostate-derived Ets factor (PDEF), a member of the Ets family of transcription factors, differs from other family members in its restricted expression in normal tissues and its unique DNA-binding motif. These interesting attributes coupled with its aberrant expression in cancer have rendered PDEF a focus of increasing interest by tumor biologists. This review provides a current understanding of the characteristics of PDEF expression and its role in breast cancer. The bulk of the evidence is consistent with PDEF overexpression in most breast tumors and an oncogenic role for this transcription factor in breast cancer. In addition, high PDEF expression in estrogen receptor-positive breast tumors showed significant correlation with poor overall survival in several independent cohorts of breast cancer patients. Together, these findings demonstrate PDEF to be an oncogenic driver of breast cancer and a biomarker of poor prognosis in this cancer. Based on this understanding and the limited expression of PDEF in normal human tissues, the development of PDEF-based therapeutics for prevention and treatment of breast cancer is also discussed.

Abstract P3-07-13: Prostate derived Ets factor, a novel driver of breast cancer independent of estrogen signaling axis and a target for immunotherapy of breast cancer

Abstract This abstract was withdrawn by the authors.

Signatures of prostate-derived Ets factor (PDEF) in cancer.

The Ets proteins are a family of transcription factors characterized by an evolutionarily conserved DNA-binding domain and have diverse biological functions including tumor suppressor as well as tumor promoter functions. They are regulated via a complex and diverse number of mechanisms and control key cellular processes. Prostate-derived Ets transcription factor (PDEF), a unique member of the ETS family, is present in tissues with high epithelial content are hormone-regulated, such as prostate, breast, salivary glands, ovaries, colon, airways, and stomach tissues. PDEF (prostate-derived Ets factor) is also referred to as SPDEF (SAM pointed domain containing Ets transcription factor), PSE (mouse homolog), or hPSE (human PSE) in the literature and is the sole member of the PDEF ETS sub-family. The role of PDEF in cancer development is still not fully elucidated though. The present article focuses on the key findings about the PDEF's biological functions, interacting proteins, and its target genes. There is a strong urge to focus on the clinical studies in larger cohort, which elucidate the regulation of PDEF and its target genes, to determine the potential of PDEF as biomarker. Based on the studies discussed in the present article, one can anticipate that PDEF offers a great potential for developing therapeutics against cancer.

Prostate-derived ets factor represses tumorigenesis and modulates epithelial-to-mesenchymal transition in bladder carcinoma cells

Prostate-derived Ets (E-twenty six) factor (PDEF), an epithelium-specific member of the Ets family of transcription factors, has been shown to play a role in suppressing the development of many epithelium-derived cancers such as prostate and breast cancer. It is not clear, however, whether PDEF is involved in the development or progression of bladder cancer. In a comparison between normal urothelium and bladder tumor tissue, we identified significant decreases of PDEF in the tumor tissue. Further, the immunohistochemistry assays indicated a significantly higher immunostaining of PDEF in low-grade bladder tumors. Additionally, the highly differentiated transitional-cell bladder carcinoma RT-4 cells expressed significantly more PDEF levels than the bladder carcinoma HT1376 and the T24 cells. Ectopic overexpression of PDEF attenuated proliferation, invasion, and tumorigenesis of bladder carcinoma cells in vitro and in vivo. PDEF enhanced the expression levels of mammary serine protease inhibitor (MASPIN), N-myc downstream regulated gene 1 (NDRG1), KAI1, and B-cell translocation gene 2 (BTG2). PDEF modulated epithelial-mesenchymal-transition (EMT) by upregulating E-cadherin expression and downregulating the expression of N-cadherin, SNAIL, SLUG, and vimentin, leading to lower migration and invasion abilities of bladder carcinoma cells. Filamentous actin (F-actin) polarization and remodeling were observed in PDEF-knockdown RT-4 cells. Our results suggest that PDEF gene expression is associated with the extent of bladder neoplasia and PDEF modulated the expressions of EMT-related genes. The induction of BTG2, NDRG1, MASPIN, and KAI1 gene expressions by PDEF may explain the inhibitory functions of PDEF on the proliferation, invasion, and tumorigenesis in bladder carcinoma cells.

164 Prostate-derived ETS factor represses cell proliferation, invasion, tumorigenesis potential via downregulation of epithelial-mesenchymal transition in human prostate carcinoma cells

164 Prostate-derived ETS factor represses cell proliferation, invasion, tumorigenesis potential via downregulation of epithelial-mesenchymal transition in human prostate carcinoma cells

Abstract LB-74: The NLR-related protein NWD1 is associated with prostate cancer and modulates androgen receptor signaling

Abstract Prostate cancer (PCa) is among the leading causes of cancer-related death in men. Androgen receptor (AR) signaling plays a seminal role in prostate development and homeostasis, and dysregulation of this pathway is intimately linked to prostate cancer pathogenesis and progression. Here, we identify the cytosolic NLR-related protein NWD1 as a novel modulator of AR signaling. We determined that expression of NWD1 becomes elevated during prostate cancer progression, based on analysis of primary tumor specimens. Experiments with cultured cells showed that NWD1 expression is up-regulated by the sex-determining region Y (SRY) proteins. Gene silencing by short hairpin RNA (shRNA), in conjunction with transcriptional profiling, showed that NWD1 is required for expression of PDEF (prostate-derived Ets factor), which is known to bind and co-regulate AR. Of note, NWD1 modulates AR protein levels. Silencing NWD1 in PCa cell lines reduces the levels of androgen-stimulated accumulation of nuclear AR and suppresses activity of androgen-driven reporter genes. NWD1 knockdown potently suppressed growth of androgen-dependent LNCaP prostate cancer cells, thus showing its functional importance in an AR-dependent tumor cell model. Proteomics analysis suggested that NWD1 associates with various molecular chaperones commonly related to AR complexes. Altogether, our data suggest a role for tumor-associated over-expression of NWD1 in the dysregulation of AR signaling in PCa. Citation Format: Ricardo G. Correa, Maryla Krajewska, Carl F. Ware, Motti Gerlic, John C. Reed. The NLR-related protein NWD1 is associated with prostate cancer and modulates androgen receptor signaling. [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 LB-74. doi:10.1158/1538-7445.AM2014-LB-74