Identification of novel TMPRSS2:ERG mechanisms in prostate cancer metastasis: involvement of MMP9 and PLXNA2

Functional interaction between receptor tyrosine kinase MET and ETS transcription factors promotes prostate cancer progression

Prostate cancer, the most common malignancy in men, has a relatively favourable prognosis. However, when it spreads to the bone, the survival rate drops dramatically. The development of bone metastases leaves patients with aggressive prostate cancer, the leading cause of death in men. Moreover, bone metastases are incurable and very painful. Hepatocyte growth factor receptor (MET) and fusion of genes encoding E26 transformation-specific (ETS) transcription factors are both involved in the progression of the disease. ETS gene fusions, in particular, have the ability to induce the migratory and invasive properties of prostate cancer cells, whereas MET receptor, through its signalling cascades, is able to activate transcription factor expression. MET signalling and ETS gene fusions are intimately linked to high-grade prostate cancer. However, the collaboration of these factors in prostate cancer progression has not yet been investigated. Here, we show, using cell models of advanced prostate cancer, that ETS translocation variant 1 (ETV1) and transcriptional regulator ERG (ERG) transcription factors (members of the ETS family) promote tumour properties, and that activation of MET signalling enhances these effects. By using a specific MET tyrosine kinase inhibitor in a humanised hepatocyte growth factor (HGF) mouse model, we also establish that MET activity is required for ETV1/ERG-mediated tumour growth. Finally, by performing a comparative transcriptomic analysis, we identify target genes that could play a relevant role in these cellular processes. Thus, our results demonstrate for the first time in prostate cancer models a functional interaction between ETS transcription factors (ETV1 and ERG) and MET signalling that confers more aggressive properties and highlight a molecular signature characteristic of this combined action.

Novel biomarkers and drug correlations of non-canonical WNT signaling in prostate and breast cancer

Prostate cancer (PCa) and breast cancer (BC) present formidable challenges in global cancer-related mortality, necessitating effective management strategies. The present study explores non-canonical Wnt signaling in PCa and BC, aiming to identify biomarkers and assess their clinical and therapeutic implications. Co-expression analyses reveal distinct gene patterns, with five overlapping genes (SULF1, ALG3, IL16, PLXNA2 and RASGFR2) exhibiting divergent expression in both cancers. Clinical relevance investigations demonstrate correlations with TNM stages and biochemical recurrence. Drug correlation analyses unveil potential therapeutic avenues, indicating that Wnt5a and ROR2 expressions are related to MEK inhibitor sensitivity in cancers. Meanwhile, further correlation analyses were conducted between drugs and the other novel non-canonical WNT genes (ALG3, IL16, SULF1, PLXNA2, and RASGRF2). Our findings contribute to understanding non-canonical Wnt signaling, offering insights into cancer progression and potential personalized treatment approaches.

Deciphering the genetic and epigenetic architecture of prostate cancer

Prostate cancer, one of the most frequently diagnosed cancers in men, leads to significant mortality worldwide. Its study is important due to the complexity and diversity in its progression, highlighting the urgent need for improved therapeutic strategies. This chapter probes into the genetic and epigenetic factors influencing prostate cancer progression, underscoring the importance of understanding the disease's molecular fundamentals for the development of targeted therapies. It specifically reviews the role of key genetic mutations in genes such as Androgen Receptor, TP53, SPOP, FOXA1 and PTEN which are crucial for the disease onset and a progression. Furthermore, it examines the impact of epigenetic modifications, including DNA methylation and histone modification, which contribute to the cancer's progression by affecting gene expression and cellular behavior. Further, in this chapter we delve into the underlying signaling mechanism, the advancements in targeting genetic and epigenetic alterations in prostate cancer. These findings have revealed promising targets for therapeutic advancements, aiming to understand and identify promising avenues for future therapies. This chapter improves our current understanding of prostate cancer genetic and epigenetic landscape, emphasizing the necessity of advancing our knowledge to refine and expand treatment options for prostate cancer patients.

Fascin-1 expression is associated with neuroendocrine prostate cancer and directly suppressed by androgen receptor

BACKGROUND

Neuroendocrine prostate cancer (NEPC) is an aggressive form of prostate cancer, arising from resistance to androgen-deprivation therapies. However, the molecular mechanisms associated with NEPC development and invasiveness are still poorly understood. Here we investigated the expression and functional significance of Fascin-1 (FSCN1), a pro-metastasis actin-bundling protein associated with poor prognosis of several cancers, in neuroendocrine differentiation of prostate cancer.

METHODS

Differential expression analyses using Genome Expression Omnibus (GEO) database, clinical samples and cell lines were performed. Androgen or antagonist's cellular treatments and knockdown experiments were used to detect changes in cell morphology, molecular markers, migration properties and in vivo tumour growth. Chromatin immunoprecipitation-sequencing (ChIP-Seq) data and ChIP assays were analysed to decipher androgen receptor (AR) binding.

RESULTS

We demonstrated that FSCN1 is upregulated during neuroendocrine differentiation of prostate cancer in vitro, leading to phenotypic changes and NEPC marker expression. In human prostate cancer samples, FSCN1 expression is restricted to NEPC tumours. We showed that the androgen-activated AR downregulates FSCN1 expression and works as a transcriptional repressor to directly suppress FSCN1 expression. AR antagonists alleviate this repression. In addition, FSCN1 silencing further impairs in vivo tumour growth.

CONCLUSION

Collectively, our findings identify FSCN1 as an AR-repressed gene. Particularly, it is involved in NEPC aggressiveness. Our results provide the rationale for the future clinical development of FSCN1 inhibitors in NEPC patients.

Plexins as Regulators of Cancer Cell Proliferation, Migration, and Invasivity

Plexins are a family of nine single-pass transmembrane receptors with a conserved GTPase activating protein (GAP) domain. The plexin family is divided into four subfamilies: Type-A, type-B, type-C, and type-D plexins. Plexins function as receptors for axon guidance factors of the semaphorin family. The semaphorin gene family contains 22 genes that are divided into eight subclasses of which subclasses three to seven represent vertebrate semaphorins. The plexins and their semaphorin ligands have important roles as regulators of angiogenesis, cancer proliferation, and metastasis. Class 3 semaphorins, with the exception of sema3E, are the only semaphorins that do not bind directly to plexins. In order to transduce their signals, they bind instead to complexes consisting of receptors of the neuropilin family and various plexins. Some plexins also form complexes with tyrosine-kinase receptors such as the epidermal growth factor receptor ErbB2, the mesenchymal epithelial transition factor receptor (MET), and the Vascular endothelial growth factor receptor 2 (VEGFR2) and, as a result, can modulate cell proliferation and tumor progression. This review focuses on the roles of the different plexins in the control of cancer cell proliferation and invasiveness. Plexins also affect tumor progression and tumor metastasis by indirect mechanisms, such as modulation of angiogenesis and immune responses. However, these topics are not covered in the present review.

ETS transcription factors: Multifaceted players from cancer progression to tumor immunity

The E26 transformation specific (ETS) family comprises 28 transcription factors, the majority of which are involved in tumor initiation and development. Serving as a group of functionally heterogeneous gene regulators, ETS factors possess a structurally conserved DNA-binding domain. As one of the most prominent families of transcription factors that control diverse cellular functions, ETS activation is modulated by multiple intracellular signaling pathways and post-translational modifications. Disturbances in ETS activity often lead to abnormal changes in oncogenicity, including cancer cell survival, growth, proliferation, metastasis, genetic instability, cell metabolism, and tumor immunity. This review systematically addresses the basics and advances in studying ETS factors, from their tumor relevance to clinical translational utility, with a particular focus on elucidating the role of ETS family in tumor immunity, aiming to decipher the vital role and clinical potential of regulation of ETS factors in the cancer field.

Plexin-A2 enables the proliferation and the development of tumors from glioblastoma derived cells

The semaphorin guidance factors receptor plexin-A2 transduces sema6A and sema6B signals and may mediate, along with plexin-A4, the anti-angiogenic effects of sema6A. When associated with neuropilins plexin-A2 also transduces the anti-angiogenic signals of sema3B. Here we show that inhibition of plexin-A2 expression in glioblastoma derived cells that express wild type p53 such as U87MG and A172 cells, or in primary human endothelial cells, strongly inhibits cell proliferation. Inhibition of plexin-A2 expression in U87MG cells also results in strong inhibition of their tumor forming ability. Knock-out of the plexin-A2 gene in U87MG cells using CRISPR/Cas9 inhibits cell proliferation which is rescued following plexin-A2 re-expression, or expression of a truncated plexin-A2 lacking its extracellular domain. Inhibition of plexin-A2 expression results in cell cycle arrest at the G2/M stage, and is accompanied by changes in cytoskeletal organization, cell flattening, and enhanced expression of senescence associated β-galactosidase. It is also associated with reduced AKT phosphorylation and enhanced phosphorylation of p38MAPK. We find that the pro-proliferative effects of plexin-A2 are mediated by FARP2 and FYN and by the GTPase activating (GAP) domain located in the intracellular domain of plexin-A2. Point mutations in these locations inhibit the rescue of cell proliferation upon re-expression of the mutated intracellular domain in the knock-out cells. In contrast re-expression of a plexin-A2 cDNA containing a point mutation in the semaphorin binding domain failed to inhibit the rescue. Our results suggest that plexin-A2 may represent a novel target for the development of anti-tumorigenic therapeutics.

Extensive germline-somatic interplay contributes to prostate cancer progression through HNF1B co-option of TMPRSS2-ERG

Genome-wide association studies have identified 270 loci conferring risk for prostate cancer (PCa), yet the underlying biology and clinical impact remain to be investigated. Here we observe an enrichment of transcription factor genes including HNF1B within PCa risk-associated regions. While focused on the 17q12/HNF1B locus, we find a strong eQTL for HNF1B and multiple potential causal variants involved in the regulation of HNF1B expression in PCa. An unbiased genome-wide co-expression analysis reveals PCa-specific somatic TMPRSS2-ERG fusion as a transcriptional mediator of this locus and the HNF1B eQTL signal is ERG fusion status dependent. We investigate the role of HNF1B and find its involvement in several pathways related to cell cycle progression and PCa severity. Furthermore, HNF1B interacts with TMPRSS2-ERG to co-occupy large proportion of genomic regions with a remarkable enrichment of additional PCa risk alleles. We finally show that HNF1B co-opts ERG fusion to mediate mechanistic and biological effects of the PCa risk-associated locus 17p13.3/VPS53/FAM57A/GEMIN4. Taken together, we report an extensive germline-somatic interaction between TMPRSS2-ERG fusion and genetic variations underpinning PCa risk association and progression.

Profile of chimeric RNAs and TMPRSS2-ERG e2e4 isoform in neuroendocrine prostate cancer

Purpose

Specific gene fusions and their fusion products (chimeric RNA and protein) have served as ideal diagnostic markers and therapeutic targets for cancer. However, few systematic studies for chimeric RNAs have been conducted in neuroendocrine prostate cancer (NEPC). In this study, we explored the landscape of chimeric RNAs in different types of prostate cancer (PCa) cell lines and aimed to identify chimeric RNAs specifically expressed in NEPC.

Methods

To do so, we employed the RNA-seq data of eight prostate related cell lines from Cancer Cell Line Encyclopedia (CCLE) for chimeric RNA identification. Multiple filtering criteria were used and the candidate chimeric RNAs were characterized at multiple levels and from various angles. We then performed experimental validation on all 80 candidates, and focused on the ones that are specific to NEPC. Lastly, we studied the clinical relevance and effect of one chimera in neuroendocrine process.

Results

Out of 80 candidates, 15 were confirmed to be expressed preferentially in NEPC lines. Among them, 13 of the 15 were found to be specifically expressed in NEPC, and four were further validated in another NEPC cell line. Importantly, in silico analysis showed that tumor malignancy may be correlated to the level of these chimeric RNAs. Clinically, the expression of TMPRSS2-ERG (e2e4) was elevated in tumor tissues and indicated poor clinical prognosis, whereas the parental wild type transcripts had no such association. Furthermore, compared to the most frequently detected TMPRSS2-ERG form (e1e4), e2e4 encodes 31 more amino acids and accelerated neuroendocrine process of prostate cancer.

Conclusions

In summary, these findings painted the landscape of chimeric RNA in NEPC and supported the idea that some chimeric RNAs may represent additional biomarkers and/or treatment targets independent of parental gene transcripts.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00893-5.

P2 purinergic receptor dysregulation in urologic disease

P2 purinergic receptors are involved in the normal function of the kidney, bladder, and prostate via signaling that occurs in response to extracellular nucleotides. Dysregulation of these receptors is common in pathological states and often associated with disease initiation, progression, or aggressiveness. Indeed, P2 purinergic receptor expression is altered across multiple urologic disorders including chronic kidney disease, polycystic kidney disease, interstitial cystitis, urinary incontinence, overactive bladder syndrome, prostatitis, and benign prostatic hyperplasia. P2 purinergic receptors are likewise indirectly associated with these disorders via receptor-mediated inflammation and pain, a common characteristic across most urologic disorders. Furthermore, select P2 purinergic receptors are overexpressed in urologic cancer including renal cell carcinoma, urothelial carcinoma, and prostate adenocarcinoma, and pre-clinical studies depict P2 purinergic receptors as potential therapeutic targets. Herein, we highlight the compelling evidence for the exploration of P2 purinergic receptors as biomarkers and therapeutic targets in urologic cancers and other urologic disease. Likewise, there is currently optimism for P2 purinergic receptor-targeted therapeutics for the treatment of inflammation and pain associated with urologic diseases. Further exploration of the common pathways linking P2 purinergic receptor dysregulation to urologic disease might ultimately help in gaining new mechanistic insight into disease processes and therapeutic targeting.

P2X4 purinergic receptors offer a therapeutic target for aggressive prostate cancer

Prostate cancer (PCa) remains a leading cause of cancer-related deaths in American men and treatment options for metastatic PCa are limited. There is a critical need to identify new mechanisms that contribute to PCa progression, that distinguish benign from lethal disease, and that have potential for therapeutic targeting. P2X4 belongs to the P2 purinergic receptor family that is commonly upregulated in cancer and is associated with poorer outcomes. We observed P2X4 protein expression primarily in epithelial cells of the prostate, a subset of CD66⁺ neutrophils, and most CD68⁺ macrophages. Our analysis of tissue microarrays representing 491 PCa cases demonstrated significantly elevated P2X4 expression in cancer- compared with benign-tissue spots, in prostatic intraepithelial neoplasia, and in PCa with ERG positivity or with PTEN loss. High-level P2X4 expression in benign tissues was likewise associated with the development of metastasis after radical prostatectomy. Treatment with the P2X4-specific agonist cytidine 5'-triphosphate (CTP) increased Transwell migration and invasion of PC3, DU145, and CWR22Rv1 PCa cells. The P2X4 antagonist 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepin-2-one (5-BDBD) resulted in a dose-dependent decrease in viability of PC3, DU145, LNCaP, CWR22Rv1, TRAMP-C2, Myc-CaP, BMPC1, and BMPC2 cells and decreased DU145 cell migration and invasion. Knockdown of P2X4 attenuated growth, migration, and invasion of PCa cells. Finally, knockdown of P2X4 in Myc-CaP cells resulted in significantly attenuated subcutaneous allograft growth in FVB/NJ mice. Collectively, these data strongly support a role for the P2X4 purinergic receptor in PCa aggressiveness and identify P2X4 as a candidate for therapeutic targeting. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Transcriptomic Profiling Revealed Plexin A2 Downregulation With Migration and Invasion Alteration in Dacarbazine-Treated Primary Melanoma Cells

Melanoma is highly heterogeneous type of malignant neoplasm that is responsible for the majority of deaths among other types of skin cancer. In the present study, we screened a list of differentially expressed genes in two primary, drug-naïve melanoma cell lines derived from patients with melanoma following treatment of the cells with the chemotherapeutic agent dacarbazine. The aim was to determine the transcriptomic profiles and associated alterations in the cell phenotype. We found the vascular endothelial growth factor A/vascular endothelial growth factor receptor 2, phosphoinositide 3-kinase/protein kinase B and focal adhesion signaling pathways to be top altered after dacarbazine treatment. In addition, we observed the expression levels of genes associated with tumor dissemination, integrin β8 and matrix metalloproteinase-1, to be diminished in both cell lines studied, the results of which were confirmed by reverse transcription-quantitative polymerase chain reaction. By contrast, plexin A2 expression was found to be upregulated in K2303 cells, where reduced migration and invasion were also observed, following dacarbazine treatment. Plexin A2 downregulation was associated with the promotion of migrative and invasive capacities in B0404 melanoma cells. Since plexin A2 is semaphorin co-receptor that is involved in focal adhesion and cell migration regulation, the present study suggested that plexin A2 may be implicated in the dacarbazine-mediated phenotypic shift of melanoma cells. We propose that the signature of cancer cell invasiveness can be revealed by using a combination of transcriptomic and functional approaches, which should be applied in the development of personalized therapeutic strategies for each patient with melanoma.

MEX3D is an oncogenic driver in prostate cancer

BACKGROUND

Prostate cancer (PCa) is the most common visceral malignancy and the second leading cause of cancer deaths in US men. The two most common genetic alterations in PCa are expression of the TMPRSS2/ERG (TE) fusion gene and loss of the PTEN tumor suppressor. These genetic alterations act cooperatively to transform prostatic epithelium but the exact mechanisms involved are unclear.

METHODS

Microarray expression analysis of immortalized prostate epithelial cells transformed by loss of PTEN and expression of the TE fusion revealed MEX3D as one of the most highly upregulated genes. MEX3D expression in prostate cancer was examined in patient samples and in silico. In vitro and in vivo studies to characterize the biological impact of MEX3D were carried out. Analysis of the TCGA PanCancer database revealed TCF3 as a major target of MEX3D. The induction of TCF3 by MEX3D was confirmed and the biological impact of TCF3 examined by in vitro studies.

RESULTS

MEX3D is expressed at increased levels in prostate cancer and is increased by decreased PTEN and/or expression of the TE fusion gene and drives soft agar colony formation, invasion and tumor formation in vivo. The known oncogenic transcription factor TCF3 is highly correlated with MEX3D in prostate cancer. MEX3D expression strongly induces TCF3, which promotes soft agar colony formation and invasion in vitro.

CONCLUSIONS

Loss of PTEN and expression of the TE fusion gene in prostate cancer strongly upregulates expression of MEX3D and its target TCF3 and promotes transformation associated phenotypes via this pathway.

Proteomic Landscape of Prostate Cancer: The View Provided by Quantitative Proteomics, Integrative Analyses, and Protein Interactomes

Prostate cancer is the second most frequent cancer of men worldwide. While the genetic landscapes and heterogeneity of prostate cancer are relatively well-known already, methodological developments now allow for studying basic and dynamic proteomes on a large scale and in a quantitative fashion. This aids in revealing the functional output of cancer genomes. It has become evident that not all aberrations at the genetic and transcriptional level are translated to the proteome. In addition, the proteomic level contains heterogeneity, which increases as the cancer progresses from primary prostate cancer (PCa) to metastatic and castration-resistant prostate cancer (CRPC). While multiple aspects of prostate adenocarcinoma proteomes have been studied, less is known about proteomes of neuroendocrine prostate cancer (NEPC). In this review, we summarize recent developments in prostate cancer proteomics, concentrating on the proteomic landscapes of clinical prostate cancer, cell line and mouse model proteomes interrogating prostate cancer-relevant signaling and alterations, and key prostate cancer regulator interactomes, such as those of the androgen receptor (AR). Compared to genomic and transcriptomic analyses, the view provided by proteomics brings forward changes in prostate cancer metabolism, post-transcriptional RNA regulation, and post-translational protein regulatory pathways, requiring the full attention of studies in the future.

Investigation of Neural Microenvironment in Prostate Cancer in Context of Neural Density, Perineural Invasion, and Neuroendocrine Profile of Tumors

Background

Cancer stroma contains the neural compartment with specific components and action. Neural microenvironment processing includes among others axonogenesis, perineural invasion (PNI), neurosignaling, and tumor cell neural/neuroendocrine differentiation. Growing data suggest that tumor-neural crosstalk plays an important function in prostate cancer (PCa) biology. However, the mechanisms involved in PNI and axonogenesis, as well as their patho-clinical correlations in this tumor are unclear.

Methods

The present study was carried out on FFPE samples of 73 PCa and 15 benign prostate (BP) cases. Immunohistochemistry with neural markers PGP9.5, TH, and NFP was performed on constructed TMAs and selected tissue sections. The analyzed parameters of tumor innervation included small nerve density (ND) measured on pan-neural marker (PGP9.5) and TH s4tained slides, as well assessment of PNI presence and morphology. The qualitative and topographic aspects were studied. In addition, the expression of neuroendocrine marker chromogranin and NPY was assessed with dedicated indexes. The correlations of the above parameters with basic patho-clinical data such as patients’ age, tumor stage, grade, angioinvasion, and ERG status were examined.

Results

The study showed that innervation parameters differed between cancer and BP. The neural network in PCa revealed heterogeneity, and ND PGP9.5 in tumor was significantly lower than in its periphery. The density of sympathetic TH-positive fibers and its proportion to all fibers was lower in cancer than in the periphery and BP samples. Perineural invasion was confirmed in 76% of cases, usually multifocally, occurring more commonly in tumors with a higher grade. NPY expression in PCa cells was common with its intensity often rising towards PNI. ERG+ tumors showed higher ND, more frequent PNI, and a higher stage. Moreover, chromogranin-positive cells were more pronounced in PCa with higher NPY expression.

Conclusions

The analysis showed an irregular axonal network in prostate cancer with higher neural density (panneural and adrenergic) in the surroundings and the invasive front. ND and PNI interrelated with NPY expression, neuroendocrine differentiation, and ERG status. The above findings support new evidence for the presence of autocrine and paracrine interactions in prostate cancer neural microenvironment.

Downregulation of the FTO m6A RNA demethylase promotes EMT-mediated progression of epithelial tumors and sensitivity to Wnt inhibitors

Post-transcriptional modifications of RNA constitute an emerging regulatory layer of gene expression. The demethylase fat mass- and obesity-associated protein (FTO), an eraser of N6-methyladenosine (m6A), has been shown to play a role in cancer, but its contribution to tumor progression and the underlying mechanisms remain unclear. Here, we report widespread FTO downregulation in epithelial cancers associated with increased invasion, metastasis and worse clinical outcome. Both in vitro and in vivo, FTO silencing promotes cancer growth, cell motility and invasion. In human-derived tumor xenografts (PDXs), FTO pharmacological inhibition favors tumorigenesis. Mechanistically, we demonstrate that FTO depletion elicits an epithelial-to-mesenchymal transition (EMT) program through increased m6A and altered 3'-end processing of key mRNAs along the Wnt signaling cascade. Accordingly, FTO knockdown acts via EMT to sensitize mouse xenografts to Wnt inhibition. We thus identify FTO as a key regulator, across epithelial cancers, of Wnt-triggered EMT and tumor progression and reveal a therapeutically exploitable vulnerability of FTO-low tumors.

Integrative analyses of scRNA-seq and scATAC-seq reveal CXCL14 as a key regulator of lymph node metastasis in breast cancer

The potentially different genetics and epigenetics in the primary tumors and metastases affect the efficacy of treatment in breast cancer patients. Nevertheless, the cellular and molecular mechanisms of breast cancer lymph node metastasis still remain elusive. Here, we employed single-cell RNA sequencing to acquire the transcriptomic profiles of individual cells from primary tumors, negative lymph nodes (NLs) and positive lymph nodes (PLs). We also performed a single-cell assay for transposase-accessible chromatin (ATAC) sequencing (scATAC-seq) of the positive and NL samples to get the chromatin accessibility profile. We identified a novel cell subpopulation with an abnormally high expression level of CXCL14 in the PL of breast cancer patients. Cell trajectory analysis also revealed that CXCL14 was increased expressed in the late pseudo-time. Moreover, based on a tissue microarray of 55 patients and the Oncomine database, we validated that CXCL14 expression was significantly higher in breast cancer patients with lymph node metastasis. Furthermore, scATAC-seq identified several transcription factors that may be potential regulation factors for the lymph node metastasis of breast cancer. Thus, our findings will improve our current understanding of the mechanism for lymph node metastasis, and they are potentially valuable in providing novel prognosis markers for the lymphatic metastasis of breast cancer.

Androgen-Driven Fusion Genes and Chimeric Transcripts in Prostate Cancer

Androgens are steroid hormones governing the male reproductive development and function. As such, androgens and the key mediator of their effects, androgen receptor (AR), have a leading role in many diseases. Prostate cancer is a major disease where AR and its transcription factor function affect a significant number of patients worldwide. While disease-related AR-driven transcriptional programs are connected to the presence and activity of the receptor itself, also novel modes of transcriptional regulation by androgens are exploited by cancer cells. One of the most intriguing and ingenious mechanisms is to bring previously unconnected genes under the control of AR. Most often this occurs through genetic rearrangements resulting in fusion genes where an androgen-regulated promoter area is combined to a protein-coding area of a previously androgen-unaffected gene. These gene fusions are distinctly frequent in prostate cancer compared to other common solid tumors, a phenomenon still requiring an explanation. Interestingly, also another mode of connecting androgen regulation to a previously unaffected gene product exists via transcriptional read-through mechanisms. Furthermore, androgen regulation of fusion genes and transcripts is not linked to only protein-coding genes. Pseudogenes and non-coding RNAs (ncRNAs), including long non-coding RNAs (lncRNAs) can also be affected by androgens and de novo functions produced. In this review, we discuss the prevalence, molecular mechanisms, and functional evidence for androgen-regulated prostate cancer fusion genes and transcripts. We also discuss the clinical relevance of especially the most common prostate cancer fusion gene TMPRSS2-ERG, as well as present open questions of prostate cancer fusions requiring further investigation.

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.

HIC1 (Hypermethylated in Cancer 1) modulates the contractile activity of prostate stromal fibroblasts and directly regulates CXCL12 expression

HIC1 (Hypermethylated In Cancer 1) a tumor suppressor gene located at 17p13.3, is frequently deleted or epigenetically silenced in many human tumors. HIC1 encodes a transcriptional repressor involved in various aspects of the DNA damage response and in complex regulatory loops with P53 and SIRT1. HIC1 expression in normal prostate tissues has not yet been investigated in detail. Here, we demonstrated by immunohistochemistry that detectable HIC1 expression is restricted to the stroma of both normal and tumor prostate tissues. By RT-qPCR, we showed that HIC1 is poorly expressed in all tested prostate epithelial lineage cell types: primary (PrEC), immortalized (RWPE1) or transformed androgen-dependent (LnCAP) or androgen-independent (PC3 and DU145) prostate epithelial cells. By contrast, HIC1 is strongly expressed in primary PrSMC and immortalized (WMPY-1) prostate myofibroblastic cells. HIC1 depletion in WPMY-1 cells induced decreases in α-SMA expression and contractile capability. In addition to SLUG, we identified stromal cell-derived factor 1/C-X-C motif chemokine 12 (SDF1/CXCL12) as a new HIC1 direct target-gene. Thus, our results identify HIC1 as a tumor suppressor gene which is poorly expressed in the epithelial cells targeted by the tumorigenic process. HIC1 is expressed in stromal myofibroblasts and regulates CXCL12/SDF1 expression, thereby highlighting a complex interplay mediating the tumor promoting activity of the tumor microenvironment. Our studies provide new insights into the role of HIC1 in normal prostatic epithelial-stromal interactions through direct repression of CXCL12 and new mechanistic clues on how its loss of function through promoter hypermethylation during aging could contribute to prostatic tumors.

Cellular and Molecular Progression of Prostate Cancer: Models for Basic and Preclinical Research

Simple Summary

The molecular progression of prostate cancer is complex and elusive. Biological research relies heavily on in vitro and in vivo models that can be used to examine gene functions and responses to the external agents in laboratory and preclinical settings. Over the years, several models have been developed and found to be very helpful in understanding the biology of prostate cancer. Here we describe these models in the context of available information on the cellular and molecular progression of prostate cancer to suggest their potential utility in basic and preclinical prostate cancer research. The information discussed herein should serve as a hands-on resource for scholars engaged in prostate cancer research or to those who are making a transition to explore the complex biology of prostate cancer.

Abstract

We have witnessed noteworthy progress in our understanding of prostate cancer over the past decades. This basic knowledge has been translated into efficient diagnostic and treatment approaches leading to the improvement in patient survival. However, the molecular pathogenesis of prostate cancer appears to be complex, and histological findings often do not provide an accurate assessment of disease aggressiveness and future course. Moreover, we also witness tremendous racial disparity in prostate cancer incidence and clinical outcomes necessitating a deeper understanding of molecular and mechanistic bases of prostate cancer. Biological research heavily relies on model systems that can be easily manipulated and tested under a controlled experimental environment. Over the years, several cancer cell lines have been developed representing diverse molecular subtypes of prostate cancer. In addition, several animal models have been developed to demonstrate the etiological molecular basis of the prostate cancer. In recent years, patient-derived xenograft and 3-D culture models have also been created and utilized in preclinical research. This review is an attempt to succinctly discuss existing information on the cellular and molecular progression of prostate cancer. We also discuss available model systems and their tested and potential utility in basic and preclinical prostate cancer research.

DNA Damage Promotes TMPRSS2-ERG Oncoprotein Destruction and Prostate Cancer Suppression via Signaling Converged by GSK3β and WEE1

TMPRSS2-ERG gene fusion occurs in approximately 50% of cases of prostate cancer (PCa), and the fusion product is a key driver of prostate oncogenesis. However, how to leverage cellular signaling to ablate TMPRSS2-ERG oncoprotein for PCa treatment remains elusive. Here, we demonstrate that DNA damage induces proteasomal degradation of wild-type ERG and TMPRSS2-ERG oncoprotein through ERG threonine-187 and tyrosine-190 phosphorylation mediated by GSK3β and WEE1, respectively. The dual phosphorylation triggers ERG recognition and degradation by the E3 ubiquitin ligase FBW7 in a manner independent of a canonical degron. DNA damage-induced TMPRSS2-ERG degradation was abolished by cancer-associated PTEN deletion or GSK3β inactivation. Blockade of DNA damage-induced TMPRSS2-ERG oncoprotein degradation causes chemotherapy-resistant growth of fusion-positive PCa cells in culture and in mice. Our findings uncover a previously unrecognized TMPRSS2-ERG protein destruction mechanism and demonstrate that intact PTEN and GSK3β signaling are essential for effective targeting of ERG protein by genotoxic therapeutics in fusion-positive PCa.

hPCL3S promotes proliferation and migration of androgen-independent prostate cancer cells

Polycomb repressive complex 2 (PRC2) allows the deposition of H3K27me3. PRC2 facultative subunits modulate its activity and recruitment such as hPCL3/PHF19, a human ortholog of Drosophila Polycomb-like protein (PCL). These proteins contain a TUDOR domain binding H3K36me3, two PHD domains and a “Winged-helix” domain involved in GC-rich DNA binding. The human PCL3 locus encodes the full-length hPCL3L protein and a shorter isoform, hPCL3S containing the TUDOR and PHD1 domains only.

In this study, we demonstrated by RT-qPCR analyses of 25 prostate tumors that hPCL3S is frequently up-regulated. In addition, hPCL3S is overexpressed in the androgen-independent DU145 and PC3 cells, but not in the androgen-dependent LNCaP cells. hPCL3S knockdown decreased the proliferation and migration of DU145 and PC3 whereas its forced expression into LNCaP increased these properties. A mutant hPCL3S unable to bind H3K36me3 (TUDOR-W50A) increased proliferation and migration of LNCaP similarly to wt hPCL3S whereas inactivation of its PHD1 domain decreased proliferation. These effects partially relied on the up-regulation of genes known to be important for the proliferation and/or migration of prostate cancer cells such as S100A16, PlexinA2, and Spondin1.

Collectively, our results suggest hPCL3S as a new potential therapeutic target in castration resistant prostate cancers.

Merging new-age biomarkers and nanodiagnostics for precision prostate cancer management

The accurate identification and stratified treatment of clinically significant early-stage prostate cancer have been ongoing concerns since the outcomes of large international prostate cancer screening trials were reported. The controversy surrounding clinical and cost benefits of prostate cancer screening has highlighted the lack of strategies for discriminating high-risk disease (that requires early treatment) from low-risk disease (that could be managed using watchful waiting or active surveillance). Advances in molecular subtyping and multiomics nanotechnology-based prostate cancer risk delineation can enable refinement of prostate cancer molecular taxonomy into clinically meaningful and treatable subtypes. Furthermore, the presence of intertumoural and intratumoural heterogeneity in prostate cancer warrants the development of novel nanodiagnostic technologies to identify clinically significant prostate cancer in a rapid, cost-effective and accurate manner. Circulating and urinary next-generation prostate cancer biomarkers for disease molecular subtyping and the newest complementary nanodiagnostic platforms for enhanced biomarker detection are promising tools for precision prostate cancer management. However, challenges in merging both aspects and clinical translation still need to be overcome.

Genetics of Thoracic and Abdominal Aortic Diseases

Dissections or ruptures of aortic aneurysms remain a leading cause of death in the developed world, with the majority of deaths being preventable if individuals at risk are identified and properly managed. Genetic variants predispose individuals to these aortic diseases. In the case of thoracic aortic aneurysm and dissections (thoracic aortic disease), genetic data can be used to identify some at-risk individuals and dictate management of the associated vascular disease. For abdominal aortic aneurysms, genetic associations have been identified, which provide insight on the molecular pathogenesis but cannot be used clinically yet to identify individuals at risk for abdominal aortic aneurysms. This compendium will discuss our current understanding of the genetic basis of thoracic aortic disease and abdominal aortic aneurysm disease. Although both diseases share several pathogenic similarities, including proteolytic elastic tissue degeneration and smooth muscle dysfunction, they also have several distinct differences, including population prevalence and modes of inheritance.

Characterization of the ERG-regulated Kinome in Prostate Cancer Identifies TNIK as a Potential Therapeutic Target

Approximately 50% of prostate cancers harbor the TMPRSS2:ERG fusion, resulting in elevated expression of the ERG transcription factor. Despite the identification of this subclass of prostate cancers, no personalized therapeutic strategies have achieved clinical implementation. Kinases are attractive therapeutic targets as signaling networks are commonly perturbed in cancers. The impact of elevated ERG expression on kinase signaling networks in prostate cancer has not been investigated. Resolution of this issue may identify novel therapeutic approaches for ERG-positive prostate cancers. In this study, we used quantitative mass spectrometry-based kinomic profiling to identify ERG-mediated changes to cellular signaling networks. We identified 76 kinases that were differentially expressed and/or phosphorylated in DU145 cells engineered to express ERG. In particular, the Traf2 and Nck-interacting kinase (TNIK) was markedly upregulated and phosphorylated on multiple sites upon ERG overexpression. Importantly, TNIK has not previously been implicated in prostate cancer. To validate the clinical relevance of these findings, we characterized expression of TNIK and TNIK phosphorylated at serine 764 (pS764) in a localized prostate cancer patient cohort and showed that nuclear enrichment of TNIK (pS764) was significantly positively correlated with ERG expression. Moreover, TNIK protein levels were dependent upon ERG expression in VCaP cells and primary cells established from a prostate cancer patient-derived xenograft. Furthermore, reduction of TNIK expression and activity by silencing TNIK expression or using the TNIK inhibitor NCB-0846 reduced cell viability, colony formation and anchorage independent growth. Therefore, TNIK represents a novel and actionable therapeutic target for ERG-positive prostate cancers that could be exploited to develop new treatments for these patients.

Polymorphism of MMP-9 gene is not associated with the risk of urinary cancers: Evidence from an updated meta-analysis

OBJECTIVE

Matrix metalloproteinases 9 (MMP-9) is a zinc-dependent gelatinase, which could decrease the expression of extracellular matrix proteins and influence the metastatic behavior of tumors. In order to draw a comprehensive and precise result about the relationship of MMP-9 and urinary cancers, we presented the current meta-analysis.

METHODS

We searched the PubMed, EMbase, Web of Science, CBM, CNKI and Wanfang databases, the cited references were also manually searched again, covering all the papers published until August 2018. Quality assessment was conducted using the Newcastle-Ottawa Scale. All the meta-analysis was conducted with Stata version 12.0 software to assess the strength of the association. Linkage disequilibrium (LD) analyses of gene polymorphisms and in-silico analysis of MMP-9 expression were also conducted to illustrate the relationship.

RESULTS

17 case-control studies comprise of more than 6154 cases and 6330 controls were enrolled and analyzed. After analyzed, we found that there is no significant association between rs3918241, rs2250889, rs17576 and rs17577 of MMP-9 and urinary cancers. LD analysis uncovered a significant LD between rs3918241 and rs17577 in CEU, CHB&CHS, ESN, and JPT populations (CEU: r² = 1.0; CHB&CHS: r² = 1.0; ESN: r² = 0.74; JPT: r² = 0.77), as well as a remarkable LD between rs17576 and rs2250889 in CHB&CHS and JPT populations (CHB&CHS: r² = 0.81; JPT: r² = 0.82). Furthermore, in-silico results indicated that the expression of MMP-9 in cancer tissue was higher than that in normal tissue in prostate cancer (Transcripts Per Kilobase Million (TPM) = 7.14 vs. 1.36, P < 0.001), bladder cancer (TPM = 14.2 vs. 2.47, P < 0.001), kidney renal clear cell carcinoma (TPM = 7.43 vs. 1.61, P < 0.001), kidney renal papillary cell carcinoma (TPM = 5.52 vs. 1.74, P = 0.002).

CONCLUSIONS

rs3918241, rs2250889, rs17576 and rs17577 polymorphisms of MMP-9 are not associated with altered risk of urinary cancer. More studies with large sample size focused on the combined effect of two or more polymorphisms of MMP-9 are necessary in the future.

TMPRSS2:ERG gene fusion expression regulates bone markers and enhances the osteoblastic phenotype of prostate cancer bone metastases

Prostate cancers have a strong propensity to metastasize to bone and promote osteoblastic lesions. TMPRSS2:ERG is the most frequent gene rearrangement identified in prostate cancer, but whether it is involved in prostate cancer bone metastases is largely unknown. We exploited an intratibial metastasis model to address this issue and we found that ectopic expression of the TMPRSS2:ERG fusion enhances the ability of prostate cancer cell lines to induce osteoblastic lesions by stimulating bone formation and inhibiting the osteolytic response. In line with these in vivo results, we demonstrate that the TMPRSS2:ERG fusion protein increases the expression of osteoblastic markers, including Collagen Type I Alpha 1 Chain and Alkaline Phosphatase, as well as Endothelin-1, a protein with a documented role in osteoblastic bone lesion formation. Moreover, we determined that the TMPRSS2:ERG fusion protein is bound to the regulatory regions of these genes in prostate cancer cell lines, and we report that the expression levels of these osteoblastic markers are correlated with the expression of the TMPRSS2:ERG fusion in patient metastasis samples. Taken together, our results reveal that the TMPRSS2:ERG gene fusion is involved in osteoblastic lesion formation induced by prostate cancer cells.

Functional Annotation of ESR1 Gene Fusions in Estrogen Receptor-Positive Breast Cancer

RNA sequencing (RNA-seq) detects estrogen receptor alpha gene (ESR1) fusion transcripts in estrogen receptor-positive (ER+) breast cancer, but their role in disease pathogenesis remains unclear. We examined multiple ESR1 fusions and found that two, both identified in advanced endocrine treatment-resistant disease, encoded stable and functional fusion proteins. In both examples, ESR1-e6>YAP1 and ESR1-e6>PCDH11X, ESR1 exons 1-6 were fused in frame to C-terminal sequences from the partner gene. Functional properties include estrogen-independent growth, constitutive expression of ER target genes, and anti-estrogen resistance. Both fusions activate a metastasis-associated transcriptional program, induce cellular motility, and promote the development of lung metastasis. ESR1-e6>YAP1- and ESR1-e6>PCDH11X-induced growth remained sensitive to a CDK4/6 inhibitor, and a patient-derived xenograft (PDX) naturally expressing the ESR1-e6>YAP1 fusion was also responsive. Transcriptionally active ESR1 fusions therefore trigger both endocrine therapy resistance and metastatic progression, explaining the association with fatal disease progression, although CDK4/6 inhibitor treatment is predicted to be effective.

MMP1/PAR1/SP/NK1R paracrine loop modulates early perineural invasion of pancreatic cancer cells

The molecular mechanism of perineural invasion (PNI) is unclear, and insufficient detection during early-stage PNI in vivo hampers its investigation. We aimed to identify a cytokine paracrine loop between pancreatic ductal adenocarcinoma (PDAC) cells and nerves and established a noninvasive method to monitor PNI in vivo.

Methods: A Matrigel/ dorsal root ganglia (DRG) system was used to observe PNI in vitro, and a murine sciatic nerve invasion model was established to examine PNI in vivo. PNI was assessed by MRI with iron oxide nanoparticle labeling. We searched publicly available datasets as well as obtained PDAC tissues from 30 patients to examine MMP1 expression in human tumor and non-tumor tissues.

Results: Our results showed that matrix metalloproteinase-1 (MMP1) activated AKT and induced protease-activated receptor-1 (PAR1)-expressing DRG to release substance P (SP), which, in turn, activated neurokinin 1 receptor (NK1R)-expressing PDAC cells and enhanced cellular migration, invasion, and PNI via SP/NK1R/ERK. In animals, hind limb paralysis and a decreased hind paw width were observed approximately 20 days after inoculation of cancer cells in the perineurium. MMP1 silencing with shRNA or treatment with either a PAR1 or an NK1R antagonist inhibited PNI. MRI detected PNI as early as 10 days after implantation of PDAC cells. PNI also induced PDAC liver metastasis. Bioinformatic analyses and pathological studies on patient tissues corroborated the clinical relevance of these findings.

Conclusion: In this study, we provided evidence that the MMP1/PAR1/SP/NK1R paracrine loop contributes to PNI during the early stage of primary tumor formation. Furthermore, we established a sensitive and non-invasive method to detect nerve invasion using iron oxide nanoparticles and MRI.

TMPRSS2-ERG Fusion Promotes Recruitment of Regulatory T cells and Tumor Growth in Prostate Cancer

BACKGROUND

This study was designed to examine the effect of transmembrane protease serine 2 ETS-related gene (TMPRSS2-ERG) fusion on regulatory T cells and tumor growth in prostate cancer, which may provide a new potential therapeutic direction for PCa.

METHODS

The effect of TMPRSS2-ERG fusion on the migration of Treg cells and tumor growth in a mouse model was investigated in vitro and in vivo. TMPRSS2-ERG fusion in biopsy tissues was performed by fluorescence in situ hybridization and the expression of ERG and Forkhead box P3 was detected by gel electrophoresis, real-time quantitative reverse transcription polymerase chain reaction and Western blot. Enzyme-linked immunosorbent assay and flow cytometry were used to analyze transforming growth factor β levels and the number of regulatory T cells, respectively. Finally, the infiltration of regulatory T cells was analyzed by Forkhead box P3 immunohistochemistry.

RESULTS

Fluorescence in situ hybridization analysis showed that the TMPRSS2-ERG fusion gene was positive in prostate cancer and that the messenger RNA and protein expression of ERG were significantly up-regulated in prostate cancer biopsy tissues. Furthermore, the number of regulatory T cells and the levels of Forkhead box P3 and transforming growth factor β were significantly increased in prostate cancer. TMPRSS2-ERG fusion increased the migration and activation of regulatory T cells in vitro and promoted subcutaneous tumor size and regulatory T cells infiltration in mouse models.

CONCLUSIONS

TMPRSS2-ERG fusion can regulate the recruitment and infiltration of regulatory T cells to promote tumor growth in prostate cancer.

Fibroblast growth factor receptor signaling plays a key role in transformation induced by the TMPRSS2/ERG fusion gene and decreased PTEN

Prostate cancer is the most common visceral malignancy and the second leading cause of cancer deaths in US men. Correlative studies in human prostate cancers reveal a frequent association of the TMPRSS2/ERG (TE) fusion gene with loss of PTEN and studies in mouse models reveal that ERG expression and PTEN loss synergistically promote prostate cancer progression. To determine the mechanism by which ERG overexpression and PTEN loss leads to transformation, we overexpressed the TE fusion gene and knocked down PTEN in an immortalized but non-transformed prostate epithelial cell line. We show that ERG overexpression in combination with PTEN loss can transform these immortalized but non-tumorigenic cells, while either alteration alone was not sufficient to fully transform these cells. Expression microarray analysis revealed extensive changes in gene expression in cells expressing the TE fusion with loss of PTEN. Among these gene expression changes was increased expression of multiple FGF ligands and receptors. We show that activation of fibroblast growth factor receptor signaling plays a key role in transformation induced by TE fusion gene expression in association with PTEN loss. In addition, in vitro and in silico analysis reveals PTEN loss is associated with widespread increases in FGF ligands and receptors in prostate cancer. Inhibitors of FGF receptor signaling are currently entering the clinic and our results suggests that FGF receptor signaling is a therapeutic target in cancers with TE fusion gene expression and PTEN loss.

CAPE suppresses migration and invasion of prostate cancer cells via activation of non-canonical Wnt signaling

Prostate cancer (PCa) was the fifth most common cancer overall in the world. More than 80% of patients died from PCa developed bone metastases. Caffeic acid phenethyl ester (CAPE) is a main bioactive component of honeybee hive propolis. Transwell and wound healing assays demonstrated that CAPE treatment suppressed the migration and invasion of PC-3 and DU-145 PCa cells. Gelatin zymography and Western blotting indicated that CAPE treatment reduced the abundance and activity of MMP-9 and MMP-2. Analysis using Micro-Western Array (MWA), a high-throughput antibody-based proteomics platform with 264 antibodies detecting signaling proteins involved in important pathways indicated that CAPE treatment induced receptor tyrosine kinase-like orphan receptor 2 (ROR2) in non-canonical Wnt signaling pathway but suppressed abundance of β-catenin, NF-κB activity, PI3K-Akt signaling, and epithelial-mesenchymal transition (EMT). Overexpression or knockdown of ROR2 suppressed or enhanced cell migration of PC-3 cells, respectively. TCF-LEF promoter binding assay revealed that CAPE treatment reduced canonical Wnt signaling. Intraperitoneal injection of CAPE reduced the metastasis of PC-3 xenografts in tail vein injection nude mice model. Immunohistochemical staining demonstrated that CAPE treatment increased abundance of ROR2 and Wnt5a but decreased protein expression of Ki67, Frizzle 4, NF-κB p65, MMP-9, Snail, β-catenin, and phosphorylation of IκBα. Clinical evidences suggested that genes affected by CAPE treatment (CTNNB1, RELA, FZD5, DVL3, MAPK9, SNAl1, ROR2, SMAD4, NFKBIA, DUSP6, and PLCB3) correlate with the aggressiveness of PCa. Our study suggested that CAPE may be a potential therapeutic agent for patients with advanced PCa.

Loss of miR-449a in ERG-associated prostate cancer promotes the invasive phenotype by inducing SIRT1

Epigenetic regulation by SIRT1, a multifaceted NAD⁺-dependent protein deacetylase, is one of the most common factors modulating cellular processes in a broad range of diseases, including prostate cancer (CaP). SIRT1 is over-expressed in CaP cells, however the associated mechanism is not well understood. To identify whether specific microRNAs might mediate this linkage, we have screened a miRNA library for differential expression in ERG-associated CaP tissues. Of 20 differentially and significantly expressed miRNAs that distinguish ERG-positive tumors from ERG-negative tumors, we find miR-449a is highly suppressed in ERG-positive tumors. We establish that SIRT1 is a direct target of miR-449a and is also induced by ERG in ERG-associated CaP. Our data suggest that attenuation of miR-449a promotes the invasive phenotype of the ERG-positive CaP in part by inducing the expression of SIRT1 in prostate cancer cells. Furthermore, we also find that suppression of SIRT1 results in a significant reduction in ERG expression in ERG-positive CaP cells, indicating a feed-back regulatory loop associated with ERG, miR-449a and SIRT1. We also report that ERG suppresses p53 acetylation perhaps through miR-449a-SIRT1 axis in CaP cells. Our findings provide new insight into the function of miRNAs in regulating ERG-associated CaP. Thus, miR-449a activation or SIRT1 suppression may represent new therapeutic opportunity for ERG-associated CaP.

Loss of FOXO1 Cooperates with TMPRSS2-ERG Overexpression to Promote Prostate Tumorigenesis and Cell Invasion

E26 transformation-specific transcription factor ERG is aberrantly overexpressed in approximately 50% of all human prostate cancer due to TMPRSS2-ERG gene rearrangements. However, mice with prostate-specific transgenic expression of prostate cancer-associated ERG alone fail to develop prostate cancer, highlighting that ERG requires other lesions to drive prostate tumorigenesis. Forkhead box (FOXO) transcription factor FOXO1 is a tumor suppressor that is frequently inactivated in human prostate cancer. Here, we demonstrate that FOXO1, but not other FOXO proteins (FOXO3 and FOXO4), binds and inhibits the transcriptional activity of prostate cancer-associated ERG independently of FOXO1 transcriptional activity. Knockdown of endogenous FOXO1 increased invasion of TMPRSS2-ERG fusion-positive VCaP cells, an effect completely abolished by ERG knockdown. Patient specimen analysis demonstrated that FOXO1 and ERG protein expression inversely correlated in a subset of human prostate cancer. Although human ERG transgene expression or homozygous deletion of Foxo1 alone in the mouse prostate failed to promote tumorigenesis, concomitant ERG transgene expression and Foxo1 deletion resulted in upregulation of ERG target genes, increased cell proliferation, and formation of high-grade prostatic intraepithelial neoplasia. Overall, we provide biochemical and genetic evidence that aberrantly activated ERG cooperates with FOXO1 deficiency to promote prostate tumorigenesis and cell invasion. Our findings enhance understanding of prostate cancer etiology and suggest that the FOXO1-ERG signaling axis can be a potential target for treatment of prostate cancer. Cancer Res; 77(23); 6524-37. ©2017 AACR.

TMPRSS2-ERG fusion promotes prostate cancer metastases in bone

Bone metastasis is the major deleterious event in prostate cancer (PCa). TMPRSS2-ERG fusion is one of the most common chromosomic rearrangements in PCa. However, its implication in bone metastasis development is still unclear. Since bone metastasis starts with the tropism of cancer cells to bone through specific migratory and invasive processes involving osteomimetic capabilities, it is crucial to better our understanding of the influence of TMPRSS2-ERG expression in the mechanisms underlying the bone tropism properties of PCa cells. We developed bioluminescent cell lines expressing the TMPRSS2-ERG fusion in order to assess its role in tumor growth and bone metastasis appearance in a mouse model. First, we showed that the TMPRSS2-ERG fusion increases cell migration and subcutaneous tumor size. Second, using intracardiac injection experiments in mice, we showed that the expression of TMPRSS2-ERG fusion increases the number of metastases in bone. Moreover, TMPRSS2-ERG affects the pattern of metastatic spread by increasing the incidence of tumors in hind limbs and spine, which are two of the most frequent sites of human PCa metastases. Finally, transcriptome analysis highlighted a series of genes regulated by the fusion and involved in the metastatic process. Altogether, our work indicates that TMPRSS2-ERG increases bone tropism of PCa cells and metastasis development.

The ETS family of oncogenic transcription factors in solid tumours

Findings over the past decade have identified aberrant activation of the ETS transcription factor family throughout all stages of tumorigenesis. Specifically in solid tumours, gene rearrangement and amplification, feed-forward growth factor signalling loops, formation of gain-of-function co-regulatory complexes and novel cis-acting mutations in ETS target gene promoters can result in increased ETS activity. In turn, pro-oncogenic ETS signalling enhances tumorigenesis through a broad mechanistic toolbox that includes lineage specification and self-renewal, DNA damage and genome instability, epigenetics and metabolism. This Review discusses these different mechanisms of ETS activation and subsequent oncogenic implications, as well as the clinical utility of ETS factors.

Analysis of Fascin-1 in Relation to Gleason Risk Classification and Nuclear ETS-Related Gene Status of Human Prostate Carcinomas: An Immunohistochemical Study of Clinically Annotated Tumours From the Wales Cancer Bank

Although prostate-specific antigen (PSA) testing can identify early-stage prostate cancers, additional biomarkers are needed for risk stratification. In one study, high levels of the actin-bundling protein, fascin-1, were correlated with lethal-phase, hormone-refractory prostate cancer. Analyses of independent samples are needed to establish the value of fascin-1 as a possible biomarker. We examined fascin-1 by immunohistochemistry in tumour specimens from the Wales Cancer Bank in comparison with nuclear-located ETS-related gene (ERG), an emerging marker for aggressive prostate cancer. Fascin-1 was elevated in focal areas of a minority of tumours, yet fascin-1-positivity did not differentiate tumours of low-, intermediate-, or high-risk Gleason scores and did not correlate with PSA status or biochemical relapse after surgery. Stromal fascin-1 correlated with high Gleason score. Nuclear ERG was upregulated in tumours but not in stroma. The complexities of fascin-1 status indicate that fascin-1 is unlikely to provide a suitable biomarker for prediction of aggressive prostate cancers.

Meta-Analysis of Genome-Wide Association Studies for Abdominal Aortic Aneurysm Identifies Four New Disease-Specific Risk Loci

Supplemental Digital Content is available in the text.

Rationale:

Abdominal aortic aneurysm (AAA) is a complex disease with both genetic and environmental risk factors. Together, 6 previously identified risk loci only explain a small proportion of the heritability of AAA.

Objective:

To identify additional AAA risk loci using data from all available genome-wide association studies.

Methods and Results:

Through a meta-analysis of 6 genome-wide association study data sets and a validation study totaling 10 204 cases and 107 766 controls, we identified 4 new AAA risk loci: 1q32.3 (SMYD2), 13q12.11 (LINC00540), 20q13.12 (near PCIF1/MMP9/ZNF335), and 21q22.2 (ERG). In various database searches, we observed no new associations between the lead AAA single nucleotide polymorphisms and coronary artery disease, blood pressure, lipids, or diabetes mellitus. Network analyses identified ERG, IL6R, and LDLR as modifiers of MMP9, with a direct interaction between ERG and MMP9.

Conclusions:

The 4 new risk loci for AAA seem to be specific for AAA compared with other cardiovascular diseases and related traits suggesting that traditional cardiovascular risk factor management may only have limited value in preventing the progression of aneurysmal disease.

Identification of TMPRSS2-ERG mechanisms in prostate cancer invasiveness: Involvement of MMP-9 and plexin B1

The relationship of TMPRSS2-ERG fusion gene with matrix metalloproteinase-9 (MMP-9) and PLXNB1 (plexin B1) in regulation of prostate cancer (PCa) aggressiveness was investigated. Fluorescence in situ hybridization (FISH) assays, qRT-PCR and western blot analysis were employed to detect the expression of TMPRSS2-ERG fusion gene, ERG, MMP-9 and PLXNB1 of 135 human tissues, which included 55 metastatic PCa cases, 50 localized PCa cases and 30 BPH cases. Then using siRNA (anti-ERG, MMP-9 and PLXNB1, respectively) downregulation of the target gene of VCaP and PC-3 cells, MTT and Transwell were performed. The results showed that the positive rate of TMPRSS2-ERG fusion was 38.1% (40/105) in total PCa samples, 47.3% (26/55) of metastatic PCa, 28.0% (14/50) of localized PCa, while 0.0% (0/30) in BPH samples. The mRNA and protein expression of ERG, MMP-9 and PLXNB1 were higher in metastatic PCa (P<0.0001), and the mRNA expression of the three genes were positively correlated with TMPRSS2-ERG fusionin PCa group (P<0.0001). siRNA transfected PCa cells can effectively downregulate the target gene expression, and we identified that MMP-9 and PLXNB1 expression were all regulated by TMPRSS2-ERG fusion gene. While only PLXNB1 contributed to TMPRSS2-ERG mediated enhancements of VCaP cell migration and invasion. The results demonstrated that PLXNB1, but not MMP-9, was the target gene directly related to TMPRSS2-ERG in PCa cell migration and invasion.

Differential expression of Low density lipoprotein Receptor-related Protein 1 (LRP-1) and matrix metalloproteinase-9 (MMP-9) in prostate gland: From normal to malignant lesions

BACKGROUND

Metalloproteinases (MMPs) are relevant modulators of inflammation, tumor microenvironment, cancer invasion and metastasis. They can be regulated by the Low density lipoprotein Receptor-related Protein 1 (LRP-1), a receptor reported to mediate the clearance of lipoproteins, extracellular matrix (ECM) macromolecules and proteinases. The aim of this study was to evaluate the expression of LRP-1, MMP-2 and MMP-9 across various grades of prostatic diseases as benign prostatic hyperplasia (BPH), BPH plus prostatitis (BPH+P), high grade prostatic intraepithelial neoplasia (HGPIN) and prostate cancer (PCa).

METHODS

LRP-1 was analyzed using immunohistochemistry and MMPs proteolytic activity by zymography in prostate tissues with different prostatic diseases.

RESULTS

LRP-1 was detected in epithelial cells in BPH (16/18), BPH+P (21/21) and HGPIN (6/6), with a staining intensity of 1+, 1+/2+ and 3+, respectively. In PCa, LRP-1 was absent in 19/27 samples while a low expression was observed in 8/27 biopsies. MMP-9 activity was higher and statistically significant in PCa than in BPH (p≤0.01).

CONCLUSION

Considering that LRP-1, by mediating the clearance of MMPs, is involved in the regulation of ECM remodeling and cell migration, we conclude that a decreased expression of LRP-1 could be involved with the increasing activity of MMPs shown in cancers.

Whole Genome Sequencing of Newly Established Pancreatic Cancer Lines Identifies Novel Somatic Mutation (c.2587G>A) in Axon Guidance Receptor Plexin A1 as Enhancer of Proliferation and Invasion

The genetic profile of human pancreatic cancers harbors considerable heterogeneity, which suggests a possible explanation for the pronounced inefficacy of single therapies in this disease. This observation has led to a belief that custom therapies based on individual tumor profiles are necessary to more effectively treat pancreatic cancer. It has recently been discovered that axon guidance genes are affected by somatic structural variants in up to 25% of human pancreatic cancers. Thus far, however, some of these mutations have only been correlated to survival probability and no function has been assigned to these observed axon guidance gene mutations in pancreatic cancer. In this study we established three novel pancreatic cancer cell lines and performed whole genome sequencing to discover novel mutations in axon guidance genes that may contribute to the cancer phenotype of these cells. We discovered, among other novel somatic variants in axon guidance pathway genes, a novel mutation in the PLXNA1 receptor (c.2587G>A) in newly established cell line SB.06 that mediates oncogenic cues of increased invasion and proliferation in SB.06 cells and increased invasion in 293T cells upon stimulation with the receptor's natural ligand semaphorin 3A compared to wild type PLXNA1 cells. Mutant PLXNA1 signaling was associated with increased Rho-GTPase and p42/p44 MAPK signaling activity and cytoskeletal expansion, but not changes in E-cadherin, vimentin, or metalloproteinase 9 expression levels. Pharmacologic inhibition of the Rho-GTPase family member CDC42 selectively abrogated PLXNA1 c.2587G>A-mediated increased invasion. These findings provide in-vitro confirmation that somatic mutations in axon guidance genes can provide oncogenic gain-of-function signals and may contribute to pancreatic cancer progression.

Edelfosine Promotes Apoptosis in Androgen-Deprived Prostate Tumors by Increasing ATF3 and Inhibiting Androgen Receptor Activity

Edelfosine is a synthetic alkyl-lysophospholipid that possesses significant antitumor activity in several human tumor models. Here, we investigated the effects of edelfosine combined with androgen deprivation (AD) in LNCaP and VCaP human prostate cancer cells. This treatment regimen greatly decreased cell proliferation compared with single agent or AD alone, resulting in higher levels of apoptosis in LNCaP compared with VCaP cells. Edelfosine caused a dose-dependent decrease in AKT activity, but did not affect the expression of total AKT in either cell line. Furthermore, edelfosine treatment inhibited the expression of androgen receptor (AR) and was associated with an increase in activating transcription factor 3 (ATF3) expression levels, a stress response gene and a negative regulator of AR transactivation. ATF3 binds to AR after edelfosine + AD and represses the transcriptional activation of AR as demonstrated by PSA promoter studies. Knockdown of ATF3 using siRNA-ATF3 reversed the inhibition of PSA promoter activity, suggesting that the growth inhibition effect of edelfosine was ATF3 dependent. Moreover, expression of AR variant 7 (ARv7) and TMPRSS2-ERG fusion gene were greatly inhibited after combined treatment with AD and edelfosine in VCaP cells. In vivo experiments using an orthotopic LNCaP model confirmed the antitumor effects of edelfosine + AD over the individual treatments. A significant decrease in tumor volume and PSA levels was observed when edelfosine and AD were combined, compared with edelfosine alone. Edelfosine shows promise in combination with AD for the treatment of prostate cancer patients. Mol Cancer Ther; 15(6); 1353-63. ©2016 AACR.

Functional analysis of the TMPRSS2:ERG fusion gene in cisplatin‑induced cell death

The TMPRSS2:E‑twenty‑six (ETS) gene fusion occurs frequently in a high proportion of patients with prostate cancer (PCa) in Western countries, and the aberrant expression of TMPRSS2: v‑ETS avian erythroblastosis virus E26 oncogene homolog (ERG), the most common form of the corresponding protein, can regulate cell migration and contribute to tumor invasion and metastasis. However, its association with other cellular events, and in particular, cell death, remain unknown. To examine the function of such fusion genes, an expression plasmid containing the TMPRSS2:ERG (T1/E5) sequence (ΔERG) from a patient sample was constructed and transiently transfected into DU145 cells, which do not express the fusion gene. It was found that the overexpression of ΔERG significantly inhibited the ability of cisplatin to induce apoptosis in DU145 cells. By contrast, VCaP cells, which do contain TMPRSS2:ERG, were sensitized to cisplatin‑induced apoptosis through siRNA inhibition of the fusion gene. To elucidate the underlying mechanism, a stable cell line expressing the ΔERG gene was constructed. Expression of ΔERG did not affect cell migration, but did protect cells from DNA damage and apoptosis induced by cisplatin. Furthermore, knockdown of ΔERG by short interfering RNA resulted in cells regaining their sensitivity to cisplatin. Finally, the gene coding for activating transcription factor 5, which is important for cell survival, may be upregulated by ΔERG. Taken together, these data point to a new function of the TMPRSS2:ERG fusion gene in regulating the apoptotic pathway.

Cigarette smoke modulates PC3 prostate cancer cell migration by altering adhesion molecules and the extracellular matrix

Prostate cancer (PCa) is the second leading cause of cancer-related mortality among American males. Studies suggest that cigarette smoking is associated with the progression of PCa; however, the molecular mechanisms underlying this process have not been extensively investigated. PCa progression is characterized by increased cell migration and alterations in extracellular matrix (ECM)- and cell adhesion molecule (CAM)-related gene expression. In the present study, the influence of cigarette smoke medium (SM) on cell migration and on the expression of ECM- and CAM-related genes in PC3 prostate adenocarcinoma cells was investigated. According to a wound-healing assay, SM treatment promoted PC3 cell migration. RNA expression levels from SM-treated and control cells were analyzed using a polymerase chain reaction (PCR) array. Of 84 genes analyzed, 27.38% (23/84) exhibited a ≥2-fold change in threshold cycle in PC3 cells following 0.5% SM treatment. Functional gene grouping analysis demonstrated that SM treatment modulated the RNA transcription of approximately 18.4% of CAMs and 33.93% of ECM-related genes. Quantitative PCR analysis showed that SM treatment led to a significant decrease in transcription levels of the following genes: Collagen 5 α-1(V), connective tissue growth factor, integrin β-2, kallmann syndrome 1, laminin α 3, matrix metallopeptidase 7 (MMP7), MMP13, secreted protein acidic cysteine-rich, thrombospondin-2 and versican; and that SM significantly increased the transcription levels of MMP2 and MMP12. Furthermore, MMP2 knockdown significantly reduced the migration of SM-treated PC3 cells. The present study provides novel insights into the association of cigarette smoking with PCa progression, via the alteration of ECM/CAM interactions.

Androgen receptor inhibits epithelial-mesenchymal transition, migration, and invasion of PC-3 prostate cancer cells

Bone metastasis is very common in prostate cancer (PCa) and causes severe pain. PC-3 is an androgen receptor (AR)-negative PCa cell line with high metastatic potential established from PCa bone metastasis. We observed that re-expression of AR, which is located in the cytoplasm in the absence of androgen, suppressed cell motility, migration, and invasion of PC-3 cells as determined by wound healing assay and transwell assay. Micro-Western Array and Western blotting analysis indicated that re-expression of AR increased APC, Akt2, Akt3, PI3K p85, phospho-PI3K p85 Tyr458, PI3K p85, and E-cadherin but decreased GSK-3β, phospho-GSK-3β Ser9, phospho-mTOR Ser2448, Skp2, NF-κB p50, Slug, N-cadherin, β-catenin, vimentin, MMP-9, and Snail. Migration and invasion of PC-3 and PC-3(AR) cells were promoted by EGF or IGF-1 but were suppressed by Casodex. Re-expression of AR reduced the activity of MMP-2 and MMP-9 in PC-3 cells. Our observations suggested that re-expressing AR suppresses migration and invasion of PC-3 cells via regulation of EMT marker proteins and MMP activity.