ERG oncogene modulates prostaglandin signaling in prostate cancer cells

The secret identities of TMPRSS2: Fertility factor, virus trafficker, inflammation moderator, prostate protector and tumor suppressor

The human TMPRSS2 gene is pathogenetically implicated in both coronaviral lung infection and prostate cancer, suggesting its potential as a drug target in both contexts. SARS-COV-2 spike polypeptides are primed by the host transmembrane TMPRSS2 protease, triggering virus fusion with epithelial cell membranes followed by an endocytotic internalisation process that bypasses normal endosomal activation of cathepsin-mediated innate immunity; viral co-opting of TMPRSS2 thus favors microbial survivability by attenuating host inflammatory responses. In contrast, most early hormone-dependent prostate cancers express TMPRSS2:ERG fusion genes arising from deletions that eliminate the TMPRSS2 coding region while juxtaposing its androgen-inducible promoter and the open reading frame of ERG, upregulating pro-inflammatory ERG while functionally disabling TMPRSS2. Moreover, inflammatory oxidative DNA damage selects for TMPRSS2:ERG-fused cancers, whereas patients treated with antiinflammatory drugs develop fewer of these fusion-dependent tumors. These findings imply that TMPRSS2 protects the prostate by enabling endosomal bypass of pathogens which could otherwise trigger inflammation-induced DNA damage that predisposes to TMPRSS2:ERG fusions. Hence, the high oncogenic selectability of TMPRSS2:ERG fusions may reflect a unique pro-inflammatory synergy between androgenic ERG gain-of-function and fusogenic TMPRSS2 loss-of-function, cautioning against the use of TMPRSS2-inhibitory drugs to prevent or treat early prostate cancer.

Corpora amylacea in prostatectomy tissue and associations with molecular, histological, and lifestyle factors

BACKGROUND

Corpora amylacea are amyloid bodies commonly found adjacent to damaged prostate epithelium. Little is known about their formation or function. The current study sought to characterize corpora amylacea in prostate tissue and to describe their relationship with clinical, histological, molecular, and lifestyle factors, especially with chronic inflammation which is associated with aggressive disease.

METHODS

We studied a cohort of 355 men with prostate cancer and tissue specimens from the Health Professionals Follow-Up Study. Pathologists examined H&E slides and undertook a standardized review for histologic data and inflammation. Trained observers counted corpora amylacea within the benign and predominately tumor areas. Immunohistochemistry biomarkers were available from tissue microarrays. We used multivariable logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) to assess associations of chronic inflammation, clinical, histological, molecular, and lifestyle factors with the presence of corpora amylacea.

RESULTS

Corpora amylacea were present in benign tissue area for 298 men (84%). Specimens with moderate-to-severe chronic inflammation were more likely to have corpora amylacea in benign regions (OR = 5.4 95%CI 1.9, 15.6). Moreover, corpora amylacea were more common in men with higher body mass index (OR = 1.13 95%CI 1.01, 1.26). In contrast, Gleason grade (OR = 0.4 95%CI 0.2, 0.8), proliferation index (OR = 0.6 95%CI 0.3, 1.2) and the presence of the TMPRSS2:ERG fusion (OR = 0.4 95%CI 0.2, 0.8) were inversely associated with corpora amylacea presence. TURP specimens were less likely to have corpora amylacea than prostatectomy specimens (OR = 0.12 95%CI 0.03, 0.47). Age, PSA, stage, biomarkers of angiogenesis and PTEN, and vasectomy were not significantly associated with corpora amylacea.

CONCLUSION

Corpora amylacea were common among men with prostate cancer and were associated with pro-inflammatory factors, some markers of less aggressive disease, and lack of the TMPRSS2:ERG fusion.

Inflammation and NF-κB Signaling in Prostate Cancer: Mechanisms and Clinical Implications

Prostate cancer is a highly prevalent form of cancer that is usually slow-developing and benign. Due to its high prevalence, it is, however, still the second most common cause of death by cancer in men in the West. The higher prevalence of prostate cancer in the West might be due to elevated inflammation from metabolic syndrome or associated comorbidities. NF-κB activation and many other signals associated with inflammation are known to contribute to prostate cancer malignancy. Inflammatory signals have also been associated with the development of castration resistance and resistance against other androgen depletion strategies, which is a major therapeutic challenge. Here, we review the role of inflammation and its link with androgen signaling in prostate cancer. We further describe the role of NF-κB in prostate cancer cell survival and proliferation, major NF-κB signaling pathways in prostate cancer, and the crosstalk between NF-κB and androgen receptor signaling. Several NF-κB-induced risk factors in prostate cancer and their potential for therapeutic targeting in the clinic are described. A better understanding of the inflammatory mechanisms that control the development of prostate cancer and resistance to androgen-deprivation therapy will eventually lead to novel treatment options for patients.

Correlation between ERG Fusion Protein and Androgen Receptor Expression by Immunohistochemistry in Prostate, Possible Role in Diagnosis and Therapy

Background: Recent discovery of gene rearrangements have brought a new look to the molecular pathogenesis of cancer. Gene fusions occur in nearly 60% of prostate adenocarcinoma, being the TMPRSS2-ERG one of the most common. Evidence supports the role of ERG fusion in tumorigenesis, progression and invasion via effecting pathways such as WNT, MYC, uPA, PI3K/AKT/PTEN, RAS/RAF/MAPF, NKX3.1, GST-pi and androgen receptor (AR) mediated signaling. Most of the ERG fusions involve 5'-partners androgen responsive. Therefore, we aimed to evaluate AR and ERG fusion protein expression on prostate tissue to find clinicopathological applications and possible role in therapy.

Methods: One hundred three samples, including prostate core biopsies and radical prostatectomy specimens, were evaluated for ERG and AR expression by immunohistochemistry (IHC). ERG rearrangement was done by fluorescence in situ hybridization (FISH) on 11 randomly selected cases and correlated with IHC results.

Results: From the total of 103 samples, eight (8/103) were benign, fourteen (14/103) had atypical glands, two (2/103) had prostatic intraepithelial neoplasia (PIN), and seventy nine (79/103) showed prostate adenocarcinoma. Forty four (44/79) tumor cases were Gleason score (GS) 6-7 (lower GS), and thirty five (35/79) were GS of 8-10 (higher GS). ERG immunoreaction was observed in 27.8% (22/79) of the tumor cases, showing higher expression in those with lower GS (68.2%, 15/22) compared to higher GS (31.8%, 7/22). Neither benign glands nor PIN stained with ERG. AR expression was observed in 75% of benign samples, 78.5% of atypical glands, 100% of PIN, and in 87.3% of tumor cases with no significant difference based on GS. Co-expression of ERG and AR was evaluated on all the tumor samples. ERG+/AR+ was seen in 77.3% (17/22) of the ERG+ tumor cases, with higher frequency in lower GS (64.7%, 11/17) compared to those with higher GS (35.3%, 6/17). All but five corresponding ERG+ tumor samples were negative for AR. Only 5 samples were ERG-/AR- corresponding to adenocarcinoma GS of 6. Presence or absence of ERG rearrangement was confirmed by FISH and correlated with IHC results.

Conclusions: Characterization of ERG status by IHC in prostate tissue has an excellent correlation with FISH. It may also assist in diagnosis since none of the benign glands stained with ERG. Co-expression of ERG+/AR+ in prostate tumor by IHC may suggest gene fusion between ERG and a 5'-partner driven by androgen signaling such as TMPRSS2, which it could represent an important ancillary test for clinical management and development of new therapeutic targets.

miR-620 promotes tumor radioresistance by targeting 15-hydroxyprostaglandin dehydrogenase (HPGD)

MicroRNA contribute to tumor radiation resistance, which is an important clinical problem, and thus we are interested in identifying and characterizing their function. We demonstrate that miR-620 contributes to radiation resistance in cancer cells by increasing proliferation, and decreasing the G2/M block. We identify the hydroxyprostaglandin dehydrogenase 15-(nicotinamide adenine dinucleotide) (HPGD/15-PGDH) tumor suppressor gene as a direct miR-620 target, which results in increased prostaglandin E2 (PGE2) levels. Furthermore, we show that siRNA targeting of HPGD or administration of exogenous PGE2 recapitulates radioresistance. Targeting of the EP2 receptor that responds to PGE2 using pharmacological or genetic approaches, abrogates radioresistance. Tumor xenograft experiments confirm that miR-620 increases proliferation and tumor radioresistance in vivo. Regulation of PGE2 levels via targeting of HPGD by miR-620 is an innovative manner by which a microRNA can induce radiation resistance.

Knocking Down TMPRSS2-ERG Fusion Oncogene by siRNA Could be an Alternative Treatment to Flutamide

Our purpose was to develop a new pharmacological approach for the treatment of prostate cancer (PCa), the most common neoplasia in men. Recently, we developed siRNA against the fusion oncogene TMPRSS2-ERG found in 50% of patients and showed an antitumoral activity in animal model. Herein, we want to compare or combine the developed siRNA to flutamide (FLU), one of the gold-standard treatment of PCa. Therefore, concomitant or subsequent association of FLU to siRNA TMPRSS2-ERG was performed in VCaP cells and in SCID mice bearing xenografted VCaP tumors. ERG, androgen receptor, cleaved-caspase-3 as well as phase 1 and 2 drug-metabolizing enzymes were investigated within tumors. We observed similar results in terms of TMPRSS2-ERG knock-down and cell viability impairment for all distinct schedules of administration. The association of siRNA TMPRSS2-ERG-squalene nanoparticles with flutamide displayed similar tumor growth inhibition as mice treated with siRNA TMPRSS2-ERG-squalene nanoparticles alone and was paralleled with modification of expression of ERG, androgen receptor, and cleaved-caspase-3. Phase 1 and 2 enzymes were essentially affected by FLU and reverted when combined with squalenoylated siRNA. In conclusion, these results confirm the therapeutic effectiveness of squalenoyl siRNA nanomedicine for PCa based on siRNA TMPRSS2-ERG.

Prognostic and predictive biomarkers in prostate cancer

Prostate cancer (PCa) is one of the leading causes of cancer death among males, especially in more developed countries. Diagnosis is often achieved at an early stage of the disease with prostate biopsy, following a screening test showing elevated serum levels of prostate-specific antigen or a positive digital rectal examination. Early detection of PCa has led to a substantial decline in the number of metastatic patients. However, the prostate-specific antigen screening test has proved to be a double-edged sword so far, as it also accounts for PCa overdiagnosis. Due to the variability of PCa features, accurate prognosis of PCa patients is very important for determining treatment options. Therefore, this review focuses on the most promising prognostic and predictive biomarkers in PCa, which are likely to play a pivotal role, alone or in panels, in the personalized medicine era that has recently emerged.

ERG oncoprotein inhibits ANXA2 expression and function in prostate cancer

Overexpression of ERG in the prostate epithelium, due to chromosomal translocations, contributes to prostate tumorigenesis. Here, genomic analysis of ERG siRNA-treated prostate cells harboring the endogenous TMPRSS2-ERG fusion revealed an inverse relationship between ERG and Annexin A2 (ANXA2) expression at both the RNA and protein level. ANXA2, a Ca(2+)-dependent and phospholipid-binding protein, is involved in various cellular functions, including maintenance of epithelial cell polarity. Mechanistic studies defined the prostate-specific transcription start site of ANXA2 and showed that the recruitment of ERG to the ANXA2 promoter is required for transcriptional repression by ERG. Knockdown of ERG enhanced the apical localization of ANXA2, the bundling of actin filaments at cell-cell junctions and formation of a polarized epithelial phenotype. ERG overexpression disrupted ANXA2-mediated cell polarity and promoted epithelial-mesenchymal transition (EMT) by inhibiting CDC42 and RHOA, and by activating cofilin. Immunohistochemistry demonstrated a reciprocal relationship of ANXA2 and ERG expression in a large fraction of primary prostate cancer clinical specimens. ANXA2 was absent or markedly reduced in ERG(+) tumors, which were mostly well differentiated. ERG(-) tumors, meanwhile, expressed moderate to high levels of ANXA2, and were either poorly differentiated or displayed subsets of poorly differentiated cells. Taken together, the transcriptional repression of ANXA2 by ERG in prostate epithelial cells plays a critical role in abrogating differentiation, promoting EMT, and in the reciprocal correlation of ERG and ANXA2 expression observed in human prostate cancer.

IMPLICATIONS

ANXA2 is a new component of the ERG network with potential to enhance biologic stratification and therapeutic targeting of ERG-stratified prostate cancers.

Methylation of the PMEPA1 gene, a negative regulator of the androgen receptor in prostate cancer

The prostate transmembrane protein androgen induced 1 (PMEPA1) gene is highly expressed in prostate epithelial cells and is a direct transcriptional target for the androgen receptor (AR). AR protein levels are controlled by the AR-PMEPA1 negative feedback loop through NEDD4-E3 ligase. Reduced expression of PMEPA1 observed in prostate tumors, suggests that loss of PMEPA1 may play critical roles in prostate tumorigenesis. This study focuses on epigenetic mechanisms of reduced PMEPA1 expression in the cancer of the prostate (CaP). Benign (n = 77) and matched malignant (n = 77) prostate epithelial cells were laser capture micro-dissected from optimum cutting temperature embedded frozen prostate sections from 42 Caucasian American (CA) and 35 African American (AA) cases. Purified DNA specimens were analyzed for CpG methylation of the PMEPA1 gene. PMEPA1 mRNA expression levels were evaluated by qRT-PCR. Analysis of PMEPA1 methylation and mRNA expression in the same tumor cell populations indicated a significant inverse correlation between mRNA expression and methylation in CaP (P = 0.0115). We noted higher frequency of CpG methylation within the evaluated first intronic region of the PMEPA1 gene in prostate tumors of CA men as compared with AA. In CaP cell lines, PMEPA1 expression was induced and AR protein levels were diminished in response to treatment with the DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (decitabine). Cell culture-based studies demonstrated that decitabine restores PMEPA1 expression in AR-positive CaP cell lines. This report reveals the potential role of PMEPA1 gene methylation in the regulation of AR stability. Thus, downregulation of PMEPA1 may result in increased AR protein levels and function in CaP cells, contributing to prostate tumorigenesis.

Androgenetic alopecia and polymorphism of the androgen receptor gene (SNP rs6152) in patients with benign prostate hyperplasia or prostate cancer

BACKGROUND

Both androgenetic alopecia (AGA) and carcinoma of the prostate (CaP) or benign prostatic hyperplasia (BPH) are androgen-dependent disorders.

OBJECTIVE

To investigate the relationships between male androgenetic alopecia, androgen receptor (AR) gene polymorphism (SNP rs6152) and clinical characteristics of BPH and prostate cancer.

METHODS

Overall, 309 male subjects with prostate disease (BPH or CaP) were examined. We evaluated the standard grades of AGA (I-VII) by Hamilton-Norwood classification and 195 patients were also assessed by phototrichogram. Prostate-specific antigen (PSA) and testosterone levels were also measured. Polymorphism rs6152 of the AR was evaluated from blood samples by PCR-RFLP. Data were statistically evaluated.

RESULTS

The expected positive correlation between age and AGA grade and the expected negative correlation between hair density and age and between anagen/telogen and AGA were found. A statistically significant difference between patients with A and G alleles in terms of AGA grade was found. The predominant G allele was more frequent in patients with higher grade of alopecia and in patients with significantly higher PSA. There was no correlation between diagnosis (BPH or CaP) and polymorphism. Patients with prostate inflammation had a statistically significant higher grade of AGA, together with higher PSA.

CONCLUSIONS

We confirmed that the AR gene polymorphism (SNP rs6152 G>A) is associated with the development of AGA and higher PSA levels in patients with BPH but not cancer. A novel finding of our study is that BPH patients with prostate inflammation had a significantly higher grade of AGA together with significantly higher PSA levels.

Loss of the NKX3.1 tumorsuppressor promotes the TMPRSS2-ERG fusion gene expression in prostate cancer

BACKGROUND

In normal prostate epithelium the TMPRSS2 gene encoding a type II serine protease is directly regulated by male hormones through the androgen receptor. In prostate cancer ERG protooncogene frequently gains hormonal control by seizing gene regulatory elements of TMPRSS2 through genomic fusion events. Although, the androgenic activation of TMPRSS2 gene has been established, little is known about other elements that may interact with TMPRSS2 promoter sequences to modulate ERG expression in TMPRSS2-ERG gene fusion context.

METHODS

Comparative genomic analyses of the TMPRSS2 promoter upstream sequences and pathway analyses were performed by the Genomatix Software. NKX3.1 and ERG genes expressions were evaluated by immunoblot or by quantitative Real-Time PCR (qRT-PCR) assays in response to siRNA knockdown or heterologous expression. QRT-PCR assay was used for monitoring the gene expression levels of NKX3.1-regulated genes. Transcriptional regulatory function of NKX3.1 was assessed by luciferase assay. Recruitment of NKX3.1 to its cognate elements was monitored by Chromatin Immunoprecipitation assay.

RESULTS

Comparative analysis of the TMPRSS2 promoter upstream sequences among different species revealed the conservation of binding sites for the androgen inducible NKX3.1 tumor suppressor. Defects of NKX3.1, such as, allelic loss, haploinsufficiency, attenuated expression or decreased protein stability represent established pathways in prostate tumorigenesis. We found that NKX3.1 directly binds to TMPRSS2 upstream sequences and negatively regulates the expression of the ERG protooncogene through the TMPRSS2-ERG gene fusion.

CONCLUSIONS

These observations imply that the frequently noted loss-of-function of NKX3.1 cooperates with the activation of TMPRSS2-ERG fusions in prostate tumorigenesis.

Evaluation of ERG responsive proteome in prostate cancer

BACKGROUND

Gene fusion between TMPRSS2 promoter and the ERG proto-oncogene is a major genomic alteration found in over half of prostate cancers (CaP), which leads to aberrant androgen dependent ERG expression. Despite extensive analysis for the biological functions of ERG in CaP, there is no systematic evaluation of the ERG responsive proteome (ERP). ERP has the potential to define new biomarkers and therapeutic targets for prostate tumors stratified by ERG expression.

METHODS

Global proteome analysis was performed by using ERG (+) and ERG (-) CaP cells isolated by ERG immunohistochemistry defined laser capture microdissection and by using TMPRSS2-ERG positive VCaP cells treated with ERG and control siRNA.

RESULTS

We identified 1,196 and 2,190 unique proteins stratified by ERG status from prostate tumors and VCaP cells, respectively. Comparative analysis of these two proteomes identified 330 concordantly regulated proteins characterizing enrichment of pathways modulating cytoskeletal and actin reorganization, cell migration, protein biosynthesis, and proteasome and ER-associated protein degradation. ERPs unique for ERG (+) tumors reveal enrichment for cell growth and survival pathways while proteasome and redox function pathways were enriched in ERPs unique for ERG (-) tumors. Meta-analysis of ERPs against CaP gene expression data revealed that Myosin VI and Monoamine oxidase A were positively and negatively correlated to ERG expression, respectively.

CONCLUSIONS

This study delineates the global proteome for prostate tumors stratified by ERG expression status. The ERP data confirm the functions of ERG in inhibiting cell differentiation and activating cell growth, and identify potentially novel biomarkers and therapeutic targets.

Emergence of ETS transcription factors as diagnostic tools and therapeutic targets in prostate cancer

The discovery of chromosomal translocations in prostate cancer has greatly enhanced our understanding of prostate cancer biology. Genomic rearrangements involving the ETS family of transcription factors are estimated to be present in 50-70% of prostate cancer cases. These rearrangements fuse the ETS factors with promoters of genes that are androgen regulated. Thus, the expression of ETS factors, such as ERG, ETV1, ETV4 and ETV5, is mediated by androgen. In-vitro and in-vivo studies suggest that overexpression of ETS proteins increase cell proliferation and confer an invasive phenotype to prostate cancer cells. Epidemiological studies demonstrate that ETS-fusion positive patients exhibit tumors corresponding to a more advanced disease. The ability of ETS factors to serve as markers for screening and diagnosing prostate cancer patients is being investigated, and the results have been largely positive to date. Additionally, ETS factors present an excellent opportunity as therapeutic targets and several strategies have been devised to directly target ETS proteins or their binding partners and downstream effectors.

Molecular subtyping of primary prostate cancer reveals specific and shared target genes of different ETS rearrangements

This work aimed to evaluate whether ETS transcription factors frequently involved in rearrangements in prostate carcinomas (PCa), namely ERG and ETV1, regulate specific or shared target genes. We performed differential expression analysis on nine normal prostate tissues and 50 PCa enriched for different ETS rearrangements using exon-level expression microarrays, followed by in vitro validation using cell line models. We found specific deregulation of 57 genes in ERG-positive PCa and 15 genes in ETV1-positive PCa, whereas deregulation of 27 genes was shared in both tumor subtypes. We further showed that the expression of seven tumor-associated ERG target genes (PLA1A, CACNA1D, ATP8A2, HLA-DMB, PDE3B, TDRD1, and TMBIM1) and two tumor-associated ETV1 target genes (FKBP10 and GLYATL2) was significantly affected by specific ETS silencing in VCaP and LNCaP cell line models, respectively, whereas the expression of three candidate ERG and ETV1 shared targets (GRPR, KCNH8, and TMEM45B) was significantly affected by silencing of either ETS. Interestingly, we demonstrate that the expression of TDRD1, the topmost overexpressed gene of our list of ERG-specific candidate targets, is inversely correlated with the methylation levels of a CpG island found at -66 bp of the transcription start site in PCa and that TDRD1 expression is regulated by direct binding of ERG to the CpG island in VCaP cells. We conclude that ETS transcription factors regulate specific and shared target genes and that TDRD1, FKBP10, and GRPR are promising therapeutic targets and can serve as diagnostic markers for molecular subtypes of PCa harboring specific fusion gene rearrangements.

Identification of TDRD1 as a direct target gene of ERG in primary prostate cancer

Molecular classification of ERG-rearranged prostate cancer clarifies the role of TMPRSS2-ERG in the development and progression of prostate cancer. The objective of our study was to identify direct ERG target genes in ERG-rearranged prostate cancer. Two independent cohorts of primary prostate cancer (Cohort A, n=48; Cohort B, n=31), a cohort of late-stage prostate cancer (n=51) and expression array data of a cohort of primary prostate tumors from a different institute (n=128) were analyzed for expression of genes that were coexpressed with ERG overexpression. By genome-wide expression analysis and Q-RT-PCR it was shown that the gene Tudor domain containing 1 (TDRD1) was by far the strongest correlated gene with ERG overexpression in both Cohort A and B. Expression array analysis of the patient cohort from a different institute showed a large overlap in genes that were positively correlated with ERG overexpression, including TDRD1. In late-stage prostate cancer, TDRD1 was also coexpressed with ERG overexpression, although a proportion of ERG-negative late-stage samples expressed TDRD1. TDRD1 expression was not associated with ETV1 overexpression. In the prostate cancer cell line VCaP, downregulation of ERG by shRNA lead to a lower expression level of TDRD1 and resulted in a decreased activity of the TDRD1 promoter. By mutation analysis we identified a functional ERG binding site in the TDRD1 promoter. Our findings show TDRD1 as the first identified upregulated direct ERG target gene that is strongly associated with ERG overexpression in primary prostate cancer.

Identification of distinct gene expression profiles between esophageal squamous cell carcinoma and adjacent normal epithelial tissues

Esophageal squamous cell carcinoma (ESCC) is a predominant type of esophageal cancer, which is a malignant tumor originating from the esophageal mucosa or gland and is aggressive with poor prognosis. Identification of new gene expression patterns would be helpful for providing new targets for the early detection and treatment of ESCC patients. In the present study, we employed cDNA array technology to compare gene expression profiles between ESCC tissues and adjacent normal epithelial tissues from ESCC patients. There was at least a 4-fold change in the expression levels of 72 genes that were significantly increased and 107 genes that were decreased in ESCC compared with normal esophageal epithelium. Among them, genes known to be involved in ESCC were found, including matrix metalloproteinases, transcription factors SOX-4 and SOX-17, the Wingless-type MMTV integration site family member 2, and cell cycle regulators. Moreover, we have newly identified the two genes that are down-regulated in ESCC: monoamine oxidase A, an enzyme that catalyzes monoamines oxidation and 15-hydroxyprostaglandin dehydrogenase [NAD+], a prostaglandin-synthesizing enzyme that physiologically antagonizes COX-2. Likewise, we found the three genes that are up-regulated in ESCC: CD7, a cell surface glycoprotein member of the immunoglobulin superfamily, LIM-domain kinase 1, a small subfamily with an unique combination of two N-terminal LIM motifs and a C-terminal protein kinase domain, and TTK protein kinase, a previously unidentified member of the kinase family. These newly identified genes may be involved in the progression of the tumor and/or represent properties specific to ESCC.

Intratumoral T but not B lymphocytes are related to clinical outcome in prostate cancer

The number of tumor-infiltrating lymphocytes is functionally important and correlates with clinical outcome in several tumor entities. Herein we explore the impact of the density of T and B lymphocytes in prostate cancer tissue on prostate-specific antigen (PSA) recurrence after prostatectomy in 3261 prostate cancer tissue samples. The number of prostate cancer-infiltrating CD3-positive T cells and CD20-positive B cells per tissue spot in a tissue microarray format was determined by immunohistochemistry and was correlated with clinical and pathological data from the same patient cohort. Patients with very low and very high numbers of CD3-positive T cells per tissue spot had a significantly shorter PSA recurrence-free survival compared to patients with intermediate numbers of T cells (p = 0.0188). Furthermore, a high number of CD3-positive T cells per tissue spot was associated with fusion type prostate cancer identified by ERG expression analysis. The number of CD20-positive B cells per tissue spot was not associated with other clinical and histopathological parameters. This study indicates that the density of T but not B cells plays a functional role in the biology of prostate cancer and may have an impact on clinical outcome in this frequent neoplasia.

Clinical potential of the ERG oncoprotein in prostate cancer

Oncogenic activation of ERG resulting from gene fusion is present in over half of all patients with prostate cancer in Western countries. Although the underlying genetic mechanisms have been extensively studied, evaluation of the ERG oncoprotein--the translational product of ERG gene fusions--has just begun. The robust correlation between ERG oncoprotein detection and gene fusion status enables rapid characterization of this protein in large patient cohorts. Recent studies have focused on characterizing the ERG oncoprotein and determining its potential role in the diagnosis and biological stratification of prostate cancer.

TMPRSS2-ERG Fusion Gene Expression in Prostate Tumor Cells and Its Clinical and Biological Significance in Prostate Cancer Progression

TMPRSS2-Ets gene fusions were identified in prostate cancers where the promoter of transmembrane protease, serine 2 (TMPRSS2) fused with coding sequence of the erythroblastosis virus E26 (Ets) gene family members. TMPRSS2 is an androgen responsive transmembrane serine protease. Ets family members are oncogenic transcription factors that contain a highly conserved Ets DNA binding domain and an N-terminal regulatory domain.Fusion of these gene results in androgen dependent transcription of Ets factor in prostate tumor cells. The ERG is the most common fusion partner with TMPRSS2 promoter in prostate cancer patients. The high prevalence of these gene fusions, in particular TMPRSS2-ERG, makes them attractive as potential diagnostic and prognostic indicators, as well as making them a potential target for tailored therapies.This review focuses on the clinical and biological significance of TMPRSS2-ERG fusions and their role in PC development and progression.

Oncogenic activation of ERG: A predominant mechanism in prostate cancer

Prevalent gene fusions involving regulatory sequences of the androgen receptor (AR) regulated genes (primarily TMPRSS2) and protein coding sequences of nuclear transcription factors of the ETS gene family (predominantly ERG) result in unscheduled androgen dependent ERG expression in prostate cancer (CaP).Cumulative data from a large number of studies in the past six years accentuate ERG alterations in more than half of all CaP patients in Western countries. Studies underscore that ERG functions are involved in the biology of CaP. ERG expression in normal context is selective to endothelial cells, specific hematopoetic cells and pre-cartilage cells. Normal functions of ERG are highlighted in hematopoetic stem cells. Emerging data continues to unravel molecular and cellular mechanisms by which ERG may contribute to CaP. Herein, we focus on biological and clinical aspects of ERG oncogenic alterations, potential of ERG-based stratification of CaP and the possibilities of targeting the ERG network in developing new therapeutic strategies for the disease.