TMPRSS2-ERG Fusion Positive Prostate Cancer Research Articles

Covid-19 pathogenesis in prostatic cancer and TMPRSS2-ERG regulatory genetic pathway.

Members of Coronaviridae family have been the source of respiratory illnesses. The outbreak of SARS-CoV-2 that produced a severe lung disease in afflicted patients in China and other countries was the reason for the incredible attention paid toward this viral infection. It is known that SARS-CoV-2 is dependent on TMPRSS2 activity for entrance and subsequent infection of the host cells and TMPRSS2 is a host cell molecule that is important for the spread of viruses such as coronaviruses.Different factors can increase the risk of prostate cancer, including older age, a family history of the disease. Androgen receptor (AR) initiates a transcriptional cascade which plays a serious role in both normal and malignant prostate tissues. TMPRSS2 protein is highly expressed in prostate secretory epithelial cells, and its expression is dependent on androgen signals. One of the molecular signs of prostate cancer is TMPRSS2-ERG gene fusion. In TMPRSS2-ERG-positive prostate cancers different patterns of changed gene expression can be detected. The possible molecular relation between fusion positive prostate cancer patients and the increased risk of lethal respiratory viral infections especially SARS-CoV-2 can candidate TMPRSS2 as an attractive drug target. The studies show that some molecules such as nicotinamide, PARP1, ETS and IL-1R can be studied deeper in order to control SARS-CoV-2 infection especially in prostate cancer patients.This review attempts to investigate the possible relation between the gene expression pattern that is produced through TMPRSS2-ERG fusion positive prostate cancer and the possible influence of these fluctuations on the pathogenesis and development of viral infections such as SARS-CoV-2.

Prevalence and genetic features of TMPRSS2-ERG fusion in Chinese patients with prostate cancer.

e17529 Background: Prostate cancer (PCa) is one of the most common malignancies, with rising incidence rate in China. The Cancer Genome Atlas (TCGA) revealed 53% of patients with PCa had ETS family gene fusions. The most frequent fusion type of ETS fusions is TMPRSS2-ERG, which may predicts resistance to taxane and androgen-deprivation therapies. The prevalence of TMPRSS2-ERG fusion in Chinese PCa patients evaluated by fluorescence in situ hybridization (FISH) or immunohistochemistry (IHC) varied from 7.5% to 78.0%. However, the sample sizes were small. In the present study, we investigated the prevalence and genetic features of TMPRSS2-ERG fusion by next generation sequencing (NGS) in a larger Chinese PCa cohort. Methods: Genomic profiling was performed through NGS from Chinese patients with PCa between January, 2017 and November, 2019. Formalin fixed paraffin-embedded (FFPE) tumor specimens or blood samples from participants were collected for NGS. IHC staining for PD-L1 expression was performed using PD-L1 IHC 22C3 pharmDx assay or Ventana PD-L1 SP263 assay. Data analyses were performed using SPSS and R 3.6.1. Results: A total of 526 Chinese PCa patients were included in this study. The median age was 70 (range, 29-90) years old. We observed 13.1% patients with a positive PD-L1 expression, 3.0% patients with MSI-H, and a median TMB of 4.0 muts/Mb (range: 0-72.9). TMPRSS2 fusions were detected in 47 (8.9%) PCa patients, and 6.8% of patients had TMPRSS2-ERG fusion, which is significantly lower than that of Caucasian patients. The PD-L1 expression pattern and TMB distribution of the TMPRSS2-ERG fusion-positive patients were similar with TMPRSS2-ERG fusion-negative patients, however no fusion-positive patients were identified as MSI-H. Among these 36 TMPRSS2-ERG fusion-positive patients, the most frequently somatic mutations were detected in TP53 (38.9%), AR (11.1%), ATM (11.1%), and PTEN (11.1%). 9 (22.2%) patients harbored somatic mutations in PI3K/ AKT/mTOR pathway that has been previously demonstrated to collaborate with ERG to promote prostate cancer progression. Conclusions: This study revealed the prevalence and genetic features of TMPRSS2-ERG fusion in Chinese PCa patients by NGS in the first time. Our results provide a better understanding of molecular features in Chinese TMPRSS2-ERG fusion-positive PCa patients.

Abstract B124: ERG mediated transcriptional regulation of DLX1 homeobox gene represents a novel mechanism underlying prostate cancer progression

Abstract Homeobox genes are the master regulatory transcription factors involved in the embryonic development and their deregulation in homeostatic biological processes can lead to cancer initiation and progression. A member of Distal less homeobox gene family (DLX), namely DLX1 plays pivotal role in the craniofacial, jaw and GABAergic (gamma aminobutyric acid) interneuron development. Higher expression levels of DLX1 has been associated with primary and metastatic prostate tumor. Moreover, DLX1 and HOXC6 are well-established diagnostic biomarkers for the early detection of prostate cancer (PCa). However, the mechanism involved in DLX1 up-regulation and functional significance in metastatic castration-resistant prostate cancer (mCRPC) progression remains unexplored. Here, we show that benign prostate epithelial cells acquire several oncogenic properties upon ectopic overexpression of DLX1. Similarly, CRISPR/Cas9 mediated DLX1 knockout in castrate-resistant 22RV1 cells show reduced proliferation, invasion, foci formation in cell-based assays, and a remarkable reduction (~80%) in tumor burden in mouse xenograft model, confirming its role in tumor progression. Moreover, our global gene expression profiling data established the role of DLX1 in regulating critical cancer hallmarks such as epithelial-to-mesenchymal transition (EMT), apoptosis and cell cycle regulation. We also demonstrate positive association between DLX1 and the most recurrent TMPRSS2-ERG gene fusion in many independent PCa cohorts, wherein, ~96% of the TMPRSS2-ERG fusion positive patients also harbour higher level of DLX1. Our ChIP-qPCR and luciferase-reporter assay data show that ERG occupies the DLX1 promoter region, and orchestrate its transcriptional control. Nevertheless, a subset of ERG-fusion negative patients also exhibits a higher DLX1 expression, where androgen receptor (AR) and AR variant 7 (AR-V7) plays critical role in transcriptional regulation of DLX1 in an ERG-independent manner. Since, Bromodomain and extra-terminal domain inhibitors (BETi) are known to inhibit the transcriptional activity of AR, AR-V7 and ERG, we examined the effect of BETi on DLX1. Interestingly, a significant decrease in the expression of DLX1 in BETi treated PCa cell lines with a concomitant loss of their oncogenic potential was observed. Taken together, our findings reveal that DLX1 serves as an oncogene thereby regulating several oncogenic properties associated with PCa progression. We discovered a novel transcriptional regulatory network involving ERG dependent up-regulation of DLX1 in TMPRSS2-ERG fusion positive PCa, while AR and AR-V7 governed expression in ERG-independent manner in CRPC cells. Conclusively, our findings suggest that BET domain inhibitors can be used as an adjuvant therapy for DLX1-positive subset of metastatic castration resistant prostate cancer patients. Citation Format: Sakshi Goel, Vipul Bhatia, Mahendra Shyamlal Palecha, Shannon Carskadon, Nallasivam Palanisamy, Bushra Ateeq. ERG mediated transcriptional regulation of DLX1 homeobox gene represents a novel mechanism underlying prostate cancer progression [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B124. doi:10.1158/1535-7163.TARG-19-B124

ERG/AKR1C3/AR Constitutes a Feed-Forward Loop for AR Signaling in Prostate Cancer Cells.

Intratumoral androgen synthesis in prostate cancer contributes to the development of castration-resistant prostate cancer (CRPC). Several enzymes responsible for androgen biosynthesis have been shown to be overexpressed in CRPC, thus contributing to CRPC in a castrated environment. The TMPRSS2-ERG transcription factor has been shown to be present in primary prostate cancer tumors as well as CRPC tumors. We hypothesize that TMPRSS2-ERG fusions regulate androgen biosynthetic enzyme (ABE) gene expression and the production of androgens, which contributes to the development of CRPC. We used a panel of assays, including lentivirus transduction, gene expression, chromatin immunoprecipitation and sequencing, liquid chromatography-mass spectrometric quantitation, immunocytochemistry, immunohistochemistry, and bioinformatics analysis of gene microarray databases, to determine ERG regulation of androgen synthesis. We found that ERG regulated the expression of the ABE AKR1C3 in prostate cancer cells via direct binding to the AKR1C3 gene. Knockdown of ERG resulted in reduced AKR1C3 expression, which caused a reduction in both DHT synthesis and PSA expression in VCaP prostate cancer cells treated with 5α-androstanedione (5α-Adione), a DHT precursor metabolite. Immunohistochemical staining revealed that ERG was coexpressed with AKR1C3 in prostate cancer tissue samples. These data suggest that AKR1C3 catalyzes the biochemical reduction of 5α-Adione to DHT in prostate cancer cells, and that ERG regulates this step through upregulation of AKR1C3 expression. Elucidation of ERG regulation of ABEs in CRPC may help to stratify TMPRSS2-ERG fusion-positive prostate cancer patients in the clinic for anti-androgen receptor-driven therapies; and AKR1C3 may serve as a valuable therapeutic target in the treatment of CRPC.

Abstract 456: ERG regulation of intracrine androgen production and castration-resistant prostate cancer progression

Abstract Introduction and Objective: Intratumoral androgen synthesis in prostate cancer (PC) contributes to the development of castration-resistant prostate cancer (CRPC). Several enzymes responsible for androgen biosynthesis have been shown to be overexpressed in CRPC, thus, contributing to CRPC in a castrated environment. However, little is known regarding their mode of regulation and expression in this context. The TMPRSS2-ERG transcription factor has been shown to be present in primary PC tumors as well as CRPC tumors; however, its biological function contributing to the development CRPC in the context of intratumoral androgen synthesis is not known. We hypothesize that TMPRSS2-ERG fusions regulate androgen biosynthetic enzyme (ABE) gene expression and the production of androgens, which contributes to the development of CRPC. Methods: We used a variety of methods including lentiviral knockdown and overexpression of ERG, qPCR, Western blot, ChIP-PCR, and Mass Spectrometry. Results: We found that (a) shRNA knockdown of ERG in VCaP PC cells significantly reduces the expression of ABE's AKR1C3, HSD17B6, and HSD17B4; (b) overexpression of truncated ERG or wild-type ERG in LNCaP PC cells significantly increases the expression of AKR1C3 and HSD17B6; (c) ERG binds to the AKR1C3 gene in VCaP PC cells; and (d) DHT synthesis is reduced in VCaP shERG cells treated with 5α-Androstanedione, a DHT precursor metabolite, compared to VCaP shScrambled controls. Conclusions: These data suggest that AKR1C3 catalyzes the biochemical reduction of 5α-Androstanedione to DHT in PC cells, and that ERG may regulate this step through upregulation of AKR1C3 expression. Elucidation of ERG regulation of ABEs in CRPC may help to stratify TMPRSS2-ERG fusion-positive PC patients in the clinic for anti-hormone driven therapies. Additionally, not all PC tumors express CYP17A1 enzyme, therefore this study emphasizes the importance of investigating ABEs other than CYP17A1, such as AKR1C3 and HSD17B6. In summary, this study addresses alternative ABE drug targets as well as possible drug resistance modes in PC treatment. Citation Format: Katelyn A. Powell, Louie Semaan, Krishna R. Maddipati, Katie (Mary) Conley-Lacomb, Yanfeng Li, Michael Cher, Sreenivasa R. Chinni. ERG regulation of intracrine androgen production and castration-resistant prostate cancer progression. [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 456. doi:10.1158/1538-7445.AM2014-456

Chemical Biology Drug Sensitivity Screen Identifies Sunitinib as Synergistic Agent with Disulfiram in Prostate Cancer Cells

BackgroundCurrent treatment options for castration- and treatment-resistant prostate cancer are limited and novel approaches are desperately needed. Our recent results from a systematic chemical biology sensitivity screen covering most known drugs and drug-like molecules indicated that aldehyde dehydrogenase inhibitor disulfiram is one of the most potent cancer-specific inhibitors of prostate cancer cell growth, including TMPRSS2-ERG fusion positive cancers. However, the results revealed that disulfiram alone does not block tumor growth in vivo nor induce apoptosis in vitro, indicating that combinatorial approaches may be required to enhance the anti-neoplastic effects.Methods and FindingsIn this study, we utilized a chemical biology drug sensitivity screen to explore disulfiram mechanistic details and to identify compounds potentiating the effect of disulfiram in TMPRSS2-ERG fusion positive prostate cancer cells. In total, 3357 compounds including current chemotherapeutic agents as well as drug-like small molecular compounds were screened alone and in combination with disulfiram. Interestingly, the results indicated that androgenic and antioxidative compounds antagonized disulfiram effect whereas inhibitors of receptor tyrosine kinase, proteasome, topoisomerase II, glucosylceramide synthase or cell cycle were among compounds sensitizing prostate cancer cells to disulfiram. The combination of disulfiram and an antiangiogenic agent sunitinib was studied in more detail, since both are already in clinical use in humans. Disulfiram-sunitinib combination induced apoptosis and reduced androgen receptor protein expression more than either of the compounds alone. Moreover, combinatorial exposure reduced metastatic characteristics such as cell migration and 3D cell invasion as well as induced epithelial differentiation shown as elevated E-cadherin expression.ConclusionsTaken together, our results propose novel combinatorial approaches to inhibit prostate cancer cell growth. Disulfiram-sunitinib combination was identified as one of the potent synergistic approaches. Since sunitinib alone has been reported to lack efficacy in prostate cancer clinical trials, our results provide a rationale for novel combinatorial approach to target prostate cancer more efficiently.

Abstract A221: A phase II study of SB939 in patients with recurrent or metastatic castration resistant prostate cancer (CRPC).

Abstract Background: SB939 is a potent oral inhibitor of class I, II and IV histone deacetylases (HDACs) with high tumor tissue selectivity. These 3 classes of HDAC are highly expressed in prostate cancer and associated with poor clinical outcomes. HDAC inhibition has been shown to abrogate androgen receptor signaling via inactivation of HSP90, and may have relevance particularly in TMPRSS2-ERG fusion positive prostate cancer. Methods: In this multicenter phase II study, pts with CRPC received SB939 60mg every other day 3 times per week × 3 weeks on a 28-day cycle. Primary endpoints were PSA response rate (RR) (>50% decline from baseline for > 4 weeks) and progression free survival (PFS). Secondary endpoints included objective response rate; response duration, overall survival; circulating tumor cell (CTC) enumeration at baseline, 6 and 12 weeks; TMPRSS2-ERG fusion analysis; correlative analysis of archival tissue; and safety. Planned sample size was 29 pts, the hypotheses (PSA RR <2% vs. ≥15%) could be tested at 10% and levels. Results: Twenty-nine pts have been accrued. Median age is 69, 25 pts had received no prior chemotherapy, ECOG performance status was 0/1 in 48%/52% of pts. Bone/lymph node/visceral metastases were present in 86%/69%/10% of pts. The median number of cycles of SB939 administered is 2 (range 1–6) with 7 pts still continuing treatment. Adverse events were generally grade 1–2, with 5 patients experiencing grade 3 events (fatigue (5 pts), vomiting (1 pt) and dyspnea (1pt)). To date, a confirmed PSA response has been noted in 2 pts (7%). In 8 RECIST-evaluable pts, there were no objective responses, and 3 pts had stable disease lasting from 3.4 to 5.6 months. CTC favorable conversion (from ≥5 at baseline to <5 at 6 or 12 weeks) was observed in 9/14 evaluable patients (64%) and unfavorable CTC levels (>5) at 6 weeks correlated with PSA progression. RT-PCR for presence of TMPRSS2-ERG transcripts from whole blood and FISH analyzes of CTC and archival tissue for TMPRSS2-ERG fusion and PTEN deletion status are ongoing. Conclusion: SB939 is well tolerated and has shown early evidence of activity in CRPC. Analysis of more mature data will be required to determine whether this agent warrants further study, and whether TMPRSS2-ERG status might predict for response to SB939. Supported by grants from the Canadian Cancer Society and the Ontario Institute for Cancer Research. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A221.

Abstract 2159: Molecular characterization of ERG mediated CXCR4 transcriptional regulation

Abstract CXCR4 is a chemokine receptor, which has been shown to be expressed in several types of tumor cells, and mediate invasion and metastasis. CXCR4 expression is transcriptionally regulated in cancer cells and is associated with aggressive phenotypes of prostate cancer. Previously, we and others have shown that ERG transcription factor regulates CXCR4 expression in prostate cancer cells. In prostate cancer patients ERG is expressed via chromosomal alterations resulting in fusion of androgen responsive TMPRSS2 promoter with the coding sequence of ERG transcription factor and systemic androgens regulate ERG expression. We further show that in TMPRSS2-ERG fusion positive prostate cancer cells androgens regulate CXCR4 expression via activating ERG transcription factor expression. The CXCR4 promoter contains several putative ERG/Ets transcription factor binding sites. We hypothesize that ERG binds to selective ERG/Ets binding sites in the CXCR4 promoter and activates CXCR4 expression. Using electrophoretic mobility shift assay experiments with each of the individual ERG/Ets binding sites with VCaP cell nuclear extracts and in vitro translated ERG protein, sequential ERG/Ets binding site deletions in CXCR4 promoter reporters, chromatin immunoprecipitation experiments with anti-ERG antibodies in TMPRSS2-ERG positive VCaP cells, and chemoinvasion studies with VCaP cells we show that: (a) ERG expressed in VCaP cells selectively interacts with specific ERG/Ets bindings sites in the CXCR4 promoter; (b) several Ets factor family members are expressed in VCaP cells; (c) in vitro translated ERG binding with ERG/Ets elements in CXCR4 promoter further confirms that selective ERG/Ets sites in CXCR4 promoter are active in binding with ERG; (d) ERG binds with CXCR4 gene promoter in VCaP cells; (e) androgens regulate CXCR4 expression in TMPRSS2-ERG fusion positive cells; and (f) androgen induced CXCR4 is active in chemoinvasion of prostate cancer cells. These data suggest that androgens regulate CXCR4 expression via ERG transcription factor expression and ERG factor may regulate CXCR4 expression by binding to the specific ERG/Ets responsive elements and activating CXCR4 transcription. These findings may provide a link between TMPRSS2-ERG translocations and enhanced metastasis of tumor cells via CXCR4 function in PC cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2159. doi:10.1158/1538-7445.AM2011-2159

Androgens Induce Functional CXCR4 through ERG Factor Expression in TMPRSS2-ERG Fusion-Positive Prostate Cancer Cells

TMPRSS2-ERG fusion transcripts have been shown to be expressed in a majority of prostate cancer (PC) patients because of chromosomal translocations or deletions involving the TMPRSS2 gene promoter and the ERG gene coding sequence. These alterations cause androgen-dependent ERG transcription factor expression in PC patients. We and others have shown that chemokine receptor CXCR4 expression is upregulated in PC tumor cells, and its ligand, CXCL12, is expressed in bone stromal cells. The CXCL12/CXCR4 axis functions in PC progression to enhance invasion and metastasis. To address the regulation of CXCR4 expression, we identified several putative ERG consensus-binding sites in the promoter region of CXCR4. We hypothesized that androgen-dependent regulation of the ERG transcription factor could induce CXCR4 expression in PC cells. Results of the current study show that 1) prostate tumor cells coexpress higher ERG and CXCR4 compared with benign tissue, 2) CXCR4 expression is increased in the TMPRSS2-ERG fusion-positive cell line, 3) ERG transcription factor binds to the CXCR4 gene promoter, 4) synthetic androgen (81881) upregulates both ERG and CXCR4 in TMPRSS2-ERG fusion-positive VCaP cells, 5) small interfering RNA-mediated down-regulation of ERG resulted in the loss of androgen-dependent regulation of CXCR4 expression in VCaP cells, and 6) 81881-activated TMPRSS2-ERG expression functionally activates CXCR4 in VCaP cells. These findings provide a link between TMPRSS2-ERG translocations and enhanced metastasis of tumor cells through CXCR4 function in PC cells.

Prevalence of TMPRSS2-ERG Fusion Prostate Cancer among Men Undergoing Prostate Biopsy in the United States

Fusion of the TMPRSS2 prostate-specific gene with the ERG transcription factor is a putatively oncogenic gene rearrangement that is commonly found in prostate cancer tissue from men undergoing prostatectomy. However, the prevalence of the fusion was less common in samples of transurethral resection of the prostate from a Swedish cohort of patients with incidental prostate cancer followed by watchful waiting, raising the question as to whether the high prevalence in prostatectomy specimens reflects selection bias. We sought to determine the prevalence of TMPRSS2-ERG gene fusion among prostate-specific antigen-screened men undergoing prostate biopsy in the United States. We studied 140 prostate biopsies from the same number of patients for TMPRSS2-ERG fusion status with a fluorescent in situ hybridization assay. One hundred and thirty-four samples (100 cancer and 34 benign) were assessable. ERG gene rearrangement was detected in 46% of prostate biopsies that were found to have prostate cancer and in 0% of benign prostate biopsies (P < 0.0001). Evaluation of morphologic features showed that cribriform growth, blue-tinged mucin, macronucleoli, and collagenous micronodules were significantly more frequent in TMPRSS2-ERG fusion-positive prostate cancer biopsies than gene fusion-negative prostate cancer biopsies (P < or = 0.04). No significant association with Gleason score was detected. In addition, non-Caucasian patients were less likely to have positive fusion status (P = 0.02). This is the first prospective North American multicenter study to characterize TMPRSS2-ERG prostate cancer prevalence in a cohort of patients undergoing needle biopsy irrespective of whether or not they subsequently undergo prostatectomy. Our results show that this gene rearrangement is common among North American men who have prostate cancer on biopsy, is absent in benign prostate biopsy, and is associated with specific morphologic features. These findings indicate a need for prospective studies to evaluate the relationship of TMPRSS2-ERG rearrangement with clinical course of screening-detected prostate cancer in North American men, and a need for the development of noninvasive screening tests to detect TMPRSS2-ERG rearrangement.

Genome-Wide Linkage Analysis of TMPRSS2-ERG Fusion in Familial Prostate Cancer

Fusion of the 5'-untranslated region of androgen-regulated TMPRSS2 promoter with ETS transcription factor family members is found frequently in prostate cancers, and recent work suggests that the most common TMPRSS2-ERG fusion is associated with an aggressive clinical phenotype compared with fusion-negative prostate cancer. Thus far, analysis of the fusion has been limited to sporadic cases of prostate cancer. In the current study, we explore for an enrichment of TMPRSS2-ERG fusion in familial prostate cancer. TMPRSS2-ERG fusion was identified using a break-apart fluorescence in situ hybridization assay on tissue microarrays. Presence of TMPRSS2-ERG fusion was associated with higher Gleason scores (P = 0.027). Of 75 patients with established history of prostate cancer, we detected the TMPRSS2-ERG fusion in 44 (59%) patients. Almost three quarters (73%) of fusion-positive patients accumulated within 16 specific families whereas only 27% were single fusion-positive cases within one family. Based on reported prevalence rates, we calculated a sibling recurrence risk ratio of up to 18.9. A subset (63%) of families with uniformly TMPRSS2-ERG-positive prostate cancer underwent a genome-wide linkage scan at 500 markers. This revealed several loci located on chromosomes #9, #18, and X that were suggestive of linkage to the TMPRSS2-ERG fusion-positive prostate cancer phenotype with linkage-of-disease scores up to 2.16 and nonparametric linkage scores up to 2.77. This suggests the presence of an inherited susceptibility to developing the TMPRSS2-ERG fusion. Given the association of TMPRSS2-ERG fusion and aggressive prostate cancer, close surveillance of relatives of patients with established fusion-positive prostate cancer or a family history of prostate cancer in general would be warranted.