ATAD2 overexpression links to enrichment of B-MYB-translational signatures and development of aggressive endometrial carcinoma

ATAD2 bromodomain in cancer therapy: current status and future perspectives

ATPase family AAA domain-containing protein 2, or ATAD2, is a novel carcinogen, essential for cancer development, chromatin remodeling, and transcriptional control. It contains a bromodomain, which binds to acetylated histones to control gene expression. It also impacts pathways that regulate the cell cycle, DNA replication, and hormone signalling. ATAD2 is overexpressed in several malignancies, including colorectal, lung, ovarian, and breast cancers, and cancer metastasis. Investigations into the function of ATAD2 in oncogenesis and its interactions may offer fresh approaches to creating cancer treatment plans. Although preclinical research is very encouraging, many unresolved aspects regarding therapeutic development remain, including toxicity being explored concurrently. Investigations into the function of ATAD2 in oncogenesis may offer fresh approaches to developing chemotherapy strategies. Most of ATAD2's molecular mechanisms behind carcinogenesis and functions are discussed here. Additionally, we included progress, including potential monoclonal antibodies, RNA-based therapies, and small chemical inhibitors, in the review. Therefore, we guarantee this study will provide researchers with new opportunities and directions for cancer therapeutics.

I-motif formation in the promoter region of the B-MYB proto-oncogene

Understanding the mechanisms of carcinogenesis is essential to combat cancer. The search for alternative targets for anticancer therapy has gained interest, particularly when focused on upstream pathways. This strategy is particularly relevant when the encoded target proteins are known - or believed - to be "undruggable", as has been reported for the B-MYB oncogene. This gene, which regulates survival and cell cycle regulation, is overexpressed in cancer and correlates with an unfavorable prognosis. In this study, we focused on the identification of the i-motif (iM) structures in the promoter region of B-MYB as a possible anticancer target, with a complete biophysical characterization and in cell formation assessment using iM-CUT&Tag. Additionally, the interaction of the iM structures with a library of small molecules was investigated.

Multiplex single-cell profiling of putative cancer stem cell markers ALDH1, SOX9, SOX2, CD44, CD133 and CD15 in endometrial cancer

The presence of cancer stem cells is linked to aggressive disease and higher risk of recurrence, and multiple markers have been proposed to detect cancer stem cells. However, a detailed evaluation of the expression patterns and the prognostic value of markers relevant for endometrial cancer is lacking. As organoid models are suggested to be enriched in cancer stem cells, such models may prove valuable to define tissue-specific cancer stem cells. To address this, imaging mass cytometry and multiplex single-cell analyses were performed on an endometrial cancer patient series including both tumor biopsies and corresponding patient-derived organoids. An antibody panel focused on cancer stem cell markers was used to identify cancer stem cell phenotypes. Over 70% of epithelial cells in the tumor biopsies expressed at least one putative cancer stem cell marker. We identified distinct cancer cell phenotypes with heterogeneous expression within individual patients and between patient samples. Few differences in the distribution of cancer cell phenotypes were observed between tumor biopsies and corresponding organoids. Cells expressing aldehyde dehydrogenase 1 (ALDH1) were more prevalent in high-grade tumors, while expression of CD44 was more prevalent in grade 1 tumors. Spatial analysis revealed significantly less interaction between ALDH1- and CD44-expressing cells. Gene expression data was used to further investigate selected markers. CD44 gene expression was associated with a favorable prognosis and was further validated using immunohistochemistry. High expression of CD44 was significantly associated with better survival. The general high expression of proposed stem cell markers may indicate alternative roles for these in endometrial cancer.

ATAD2 and TWIST1 Interaction Promotes MYC Activation in Colorectal Carcinoma

ATPase family AAA domain-containing protein 2 (ATAD2) is significantly up-regulated in many cancer types and contributes to poor patient outcomes. ATAD2 exhibits a multidomain architecture comprising an N-terminal acidic domain, two AAA+ ATPase domains, a bromodomain, and a C-terminal domain. The AAA+ ATPase domain facilitates protein oligomerization and ATP binding, while the bromodomain recognizes acetylated lysine in histones and nonhistone proteins. ATAD2 involvement in cancer extends across multiple signaling pathways, such as Rb-E2F1, PI3K/AKT, and TGF-β1/Smad3, which promotes cell proliferation and cancer progression. Herein, we report that ATAD2 directly interacts with TWIST1, and both N-terminal regions of proteins mediate the interaction. Immunofluorescence experiments suggested that ATAD2 and TWIST1 primarily colocalize in the nucleus. Notably, our qPCR results revealed the functional significance of ATAD2-TWIST1 interaction by demonstrating their synergistic effect on the transcriptional activation of MYC in colorectal carcinoma cell lines. Moreover, the ChIP-qPCR result further indicates that ATAD2 and TWIST1 significantly localize in the promoter of the MYC gene. In addition, analysis of The Cancer Genome Atlas (TCGA) and Clinical Proteomic Tumor Analysis Consortium (CPTAC) data suggests a correlation between ATAD2, TWIST1, and MYC overexpression and poor survival rates in colorectal carcinoma. Lastly, the overexpression of ATAD2 and TWIST1 enhances cell proliferation, emphasizing their role in colorectal carcinoma progression through MYC activation. Together, these results suggest that ATAD2 is a crucial factor in TWIST1-dependent MYC gene activation, resulting in an active ATAD2-TWIST1-MYC axis that contributes to colon cancer cell proliferation.

Single-cell profiling of low-stage endometrial cancers identifies low epithelial vimentin expression as a marker of recurrent disease

BACKGROUND

Identification of aggressive low-stage endometrial cancers is challenging. So far, studies have failed to pinpoint robust features or biomarkers associated with risk of recurrence for these patients.

METHODS

Imaging mass cytometry was used to examine single-cell expression of 23 proteins in 36 primary FIGO IB endometrial cancers, of which 17 recurred. Single-cell information was extracted for each tumor and unsupervised clustering was used to identify cellular phenotypes. Distinct phenotypes and cellular neighborhoods were compared in relation to recurrence. Cellular differences were validated in a separate gene expression dataset and the TCGA EC dataset. Vimentin protein expression was evaluated by IHC in pre-operative samples from 518 patients to validate its robustness as a prognostic marker.

FINDINGS

The abundance of epithelial, immune or stromal cell types did not associate with recurrence. Clustering of patients based on tumor single cell marker expression revealed distinct patient clusters associated with outcome. A cell population neighboring CD8+ T cells, defined by vimentin, ER, and PR expressing epithelial cells, was more prevalent in non-recurrent tumors. Importantly, lower epithelial vimentin expression and lower gene expression of VIM associated with worse recurrence-free survival. Loss and low expression of vimentin was validated by IHC as a robust marker for recurrence in FIGO I stage disease and predicted poor prognosis also when including all patients and in endometrioid patients only.

INTERPRETATION

This study reveals distinct characteristics in low-stage tumors and points to vimentin as a clinically relevant marker that may aid in identifying a here to unidentified subgroup of high-risk patients.

FUNDING

A full list of funding that contributed to this study can be found in the Acknowledgements section.

ATPase family AAA domain-containing protein 2 (ATAD2): From an epigenetic modulator to cancer therapeutic target

ATPase family AAA domain-containing protein 2 (ATAD2) has been widely reported to be a new emerging oncogene that is closely associated with epigenetic modifications in human cancers. As a coactivator of transcription factors, ATAD2 can participate in epigenetic modifications and regulate the expression of downstream oncogenes or tumor suppressors, which may be supported by the enhancer of zeste homologue 2. Moreover, the dominant structure (AAA + ATPase and bromine domains) can make ATAD2 a potential therapeutic target in cancer, and some relevant small-molecule inhibitors, such as GSK8814 and AZ13824374, have also been discovered. Thus, in this review, we focus on summarizing the structural features and biological functions of ATAD2 from an epigenetic modulator to a cancer therapeutic target, and further discuss the existing small-molecule inhibitors targeting ATAD2 to improve potential cancer therapy. Together, these inspiring findings would shed new light on ATAD2 as a promising druggable target in cancer and provide a clue on the development of candidate anticancer drugs.

A targetable MYBL2-ATAD2 axis governs cell proliferation in ovarian cancer

The chromatin-modifying enzyme ATAD2 confers oncogenic competence and proliferative advantage in malignances. We previously identified ATAD2 as a marker and driver of cell proliferation in ovarian cancer (OC); however, the mechanisms whereby ATAD2 is regulated and involved in cell proliferation are still unclear. Here, we disclose that ATAD2 displays a classical G2/M gene signature, functioning to facilitate mitotic progression. ATAD2 ablation caused mitotic arrest and decreased the ability of OC cells to pass through nocodazole-arrested mitosis. ChIP-seq data analyses demonstrated that DREAM and MYBL2-MuvB (MMB), two switchable MuvB-based complexes, bind the CHR elements in the ATAD2 promoter, representing a typical feature and principle mechanism of the periodic regulation of G2/M genes. As a downstream target of MYBL2, ATAD2 deletion significantly impaired MYBL2-driven cell proliferation. Intriguingly, ATAD2 silencing also fed back to destabilize the MYBL2 protein. The significant coexpression of MYBL2 and ATAD2 at both the bulk tissue and single-cell levels highlights the existence of the MYBL2-ATAD2 signaling in OC patients. This signaling is activated during tumorigenesis and correlated with TP53 mutation, and its hyperactivation was found especially in high-grade serous and drug-resistant OCs. Disrupting this signaling by CRISPR/Cas9-mediated ATAD2 ablation inhibited the in vivo growth of OC in a subcutaneous tumor xenograft mouse model, while pharmacologically targeting this signaling with an ATAD2 inhibitor demonstrated high therapeutic efficacy in both drug-sensitive and drug-resistant OC cells. Collectively, we identified a novel MYBL2-ATAD2 proliferative signaling axis and highlighted its potential application in developing new therapeutic strategies, especially for high-grade serous and drug-resistant OCs.

Genome-wide survey of D/E repeats in human proteins uncovers their instability and aids in identifying their role in the chromatin regulator ATAD2

D/E repeats are stretches of aspartic and/or glutamic acid residues found in over 150 human proteins. We examined genomic stability of D/E repeats and functional characteristics of D/E repeat-containing proteins vis-à-vis the proteins with poly-Q or poly-A repeats, which are known to undergo pathologic expansions. Mining of tumor sequencing data revealed that D/E repeat-coding regions are similar to those coding poly-Qs and poly-As in increased incidence of trinucleotide insertions/deletions but differ in types and incidence of substitutions. D/E repeat-containing proteins preferentially function in chromatin metabolism and are the more likely to be nuclear and interact with core histones, the longer their repeats are. One of the longest D/E repeats of unknown function is in ATAD2, a bromodomain family ATPase frequently overexpressed in tumors. We demonstrate that D/E repeat deletion in ATAD2 suppresses its binding to nascent and mature chromatin and to the constitutive pericentromeric heterochromatin, where ATAD2 represses satellite transcription.

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Many human proteins contain runs of aspartic/glutamic acid residues (D/E repeats)

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D/E repeats show increased incidence of in-frame insertions/deletions in tumors

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Nuclear and histone-interacting proteins often have long D/E repeats

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D/E repeat of the oncogene ATAD2 controls its binding to pericentric chromatin

ATAD2 Upregulation Promotes Tumor Growth and Angiogenesis in Endometrial Cancer and Is Associated with Its Immune Infiltration

Background

Endometrial cancer is one of the three major gynecologic malignancies, and its incidence continues to rise. ATPase family AAA structural domain-containing protein 2 (ATAD2) is an ATPase protein, which is an independent factor for poor prognosis in endometrial cancer. However, its role in the disease is yet to be determined.

Methods

The Tumor IMmune Estimation Resource (TIMER) database was used to assess ATAD2 expression in pan-cancer, and the relevance of ATAD2 expression in Uterine Corpus Endometrial Carcinoma (UCEC) in clinical settings was obtained using Gene Expression Profiling Interactive Analysis (GEPIA) and UALCAN analysis. In addition, the Human Protein Atlas database was used to assess ATAD2 protein expression in UCEC. Furthermore, in vitro molecular biology and in vivo functional experiments were employed to ascertain the effect of ATAD2 expression on tumor angiogenesis and tumor growth. UALCAN was used to screen for ATAD2 coexpressed genes, and Sangerbox was utilized to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of these coexpressed genes. Finally, the TIMER, Tumor Immune System Interaction and Drug Bank (TISIDB), and GEPIA databases were used to analyze the relationship between ATAD2 and immune infiltration.

Results

ATAD2 is highly expressed in a variety of tumors, and in UCEC, it plays the role of a protooncogene. Basic experiments revealed that ATAD2 promotes vascular endothelial growth factor expression in endometrial cancer and affects tumor growth and angiogenesis. In addition, GO and KEGG enrichment analyses showed that ATAD2-associated genes were chiefly enriched in certain signaling pathways, such as herpes simplex virus 1 infection and that ATAD2 was associated with immune infiltration in UCEC.

Conclusion

Our findings suggest that ATAD2 promotes tumor growth and angiogenesis in endometrial cancer. Furthermore, ATAD2 is associated with immune infiltration and is a potential diagnostic and therapeutic target.

Tumor-Promoting ATAD2 and Its Preclinical Challenges

ATAD2 has received extensive attention in recent years as one prospective oncogene with tumor-promoting features in many malignancies. ATAD2 is a highly conserved bromodomain family protein that exerts its biological functions by mainly AAA ATPase and bromodomain. ATAD2 acts as an epigenetic decoder and transcription factor or co-activator, which is engaged in cellular activities, such as transcriptional regulation, DNA replication, and protein modification. ATAD2 has been reported to be highly expressed in a variety of human malignancies, including gastrointestinal malignancies, reproductive malignancies, urological malignancies, lung cancer, and other types of malignancies. ATAD2 is involved in the activation of multiple oncogenic signaling pathways and is closely associated with tumorigenesis, progression, chemoresistance, and poor prognosis, but the oncogenic mechanisms vary in different cancer types. Moreover, the direct targeting of ATAD2’s bromodomain may be a very challenging task. In this review, we summarized the role of ATAD2 in various types of malignancies and pointed out the pharmacological direction.

Coordination of Di-Acetylated Histone Ligands by the ATAD2 Bromodomain

The ATPase Family, AAA domain-containing protein 2 (ATAD2) bromodomain (BRD) has a canonical bromodomain structure consisting of four α-helices. ATAD2 functions as a co-activator of the androgen and estrogen receptors as well as the MYC and E2F transcription factors. ATAD2 also functions during DNA replication, recognizing newly synthesized histones. In addition, ATAD2 is shown to be up-regulated in multiple forms of cancer including breast, lung, gastric, endometrial, renal, and prostate. Furthermore, up-regulation of ATAD2 is strongly correlated with poor prognosis in many types of cancer, making the ATAD2 bromodomain an innovative target for cancer therapeutics. In this study, we describe the recognition of histone acetyllysine modifications by the ATAD2 bromodomain. Residue-specific information on the complex formed between the histone tail and the ATAD2 bromodomain, obtained through nuclear magnetic resonance spectroscopy (NMR) and X-ray crystallography, illustrates key residues lining the binding pocket, which are involved in coordination of di-acetylated histone tails. Analytical ultracentrifugation, NMR relaxation data, and isothermal titration calorimetry further confirm the monomeric state of the functionally active ATAD2 bromodomain in complex with di-acetylated histone ligands. Overall, we describe histone tail recognition by ATAD2 BRD and illustrate that one acetyllysine group is primarily engaged by the conserved asparagine (N1064), the "RVF" shelf residues, and the flexible ZA loop. Coordination of a second acetyllysine group also occurs within the same binding pocket but is essentially governed by unique hydrophobic and electrostatic interactions making the di-acetyllysine histone coordination more specific than previously presumed.

Functional Roles of Bromodomain Proteins in Cancer

Histone acetylation is generally associated with an open chromatin configuration that facilitates many cellular processes including gene transcription, DNA repair, and DNA replication. Aberrant levels of histone lysine acetylation are associated with the development of cancer. Bromodomains represent a family of structurally well-characterized effector domains that recognize acetylated lysines in chromatin. As part of their fundamental reader activity, bromodomain-containing proteins play versatile roles in epigenetic regulation, and additional functional modules are often present in the same protein, or through the assembly of larger enzymatic complexes. Dysregulated gene expression, chromosomal translocations, and/or mutations in bromodomain-containing proteins have been correlated with poor patient outcomes in cancer. Thus, bromodomains have emerged as a highly tractable class of epigenetic targets due to their well-defined structural domains, and the increasing ease of designing or screening for molecules that modulate the reading process. Recent developments in pharmacological agents that target specific bromodomains has helped to understand the diverse mechanisms that bromodomains play with their interaction partners in a variety of chromatin processes, and provide the promise of applying bromodomain inhibitors into the clinical field of cancer treatment. In this review, we explore the expression and protein interactome profiles of bromodomain-containing proteins and discuss them in terms of functional groups. Furthermore, we highlight our current understanding of the roles of bromodomain-containing proteins in cancer, as well as emerging strategies to specifically target bromodomains, including combination therapies using bromodomain inhibitors alongside traditional therapeutic approaches designed to re-program tumorigenesis and metastasis.

Emerging oncogene ATAD2: Signaling cascades and therapeutic initiatives

ATAD2 is a promising oncoprotein with tumor-promoting functions in many cancers. It is a valid cancer drug-target and a potential cancer-biomarker for multiple malignancies. As a cancer/testis antigen (CTA), ATAD2 could also be a probable candidate for immunotherapy. It is a unique CTA that belongs to both AAA+ ATPase and bromodomain family proteins. Since 2007, several research groups have been reported on the pleiotropic oncogenic functions of ATAD2 in diverse signaling pathways, including Rb/E2F-cMyc pathway, steroid hormone signaling pathway, p53 and p38-MAPK-mediated apoptotic pathway, AKT pathway, hedgehog signaling pathway, HIF1α signaling pathway, and Epithelial to Mesenchymal Transition (EMT) pathway in various cancers. In all these pathways, ATAD2 participates in chromatin dynamics, DNA replication, and gene transcription, demonstrating its role as an epigenetic reader and transcription factor or coactivator to promote tumorigenesis. However, despite the progress, an overall mechanism of ATAD2-mediated oncogenesis in diverse origin is elusive. In this review, we summarize the accumulated evidence to envision the overall ATAD2 signaling networks during carcinogenesis and highlight the area where missing links await further research. Besides, the structure-function aspect of ATAD2 is also discussed. Since the efforts have already been initiated to explore targeted drug molecules and RNA-based therapeutic alternatives against ATAD2, their potency and prospects have been elucidated. Together, we believe this is a well-rounded review on ATAD2, facilitating a new drift in ATAD2 research, essential for its clinical implication as a biomarker and/or cancer drug-target.

TCGA dataset screening for genes implicated in endometrial cancer using RNA-seq profiling

The molecular basis of the mechanism and the potential biomarkers of endometrial cancer (EC) remain to be studied. In the present study, we hypothesized that the comprehensive characterization of transcriptional changes in EC could help achieve this aim. By taking advantage of RNA-seq data from The Cancer Genome Atlas, we determined the profile of differently expressed genes (DEGs) between EC tumor tissues and normal samples. On this basis, we performed Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways enrichment analyses. The interacting partners for each of the DEGs were explored and a protein-protein interaction network was constructed. Consequently, 10 hub genes were identified and their association with mortality in EC patients was investigated. The genes, AURKA, CENPA, and KIF2C, were found to be potential biomarkers for EC with a significant prognostic effect. Our work provided a basis for EC studies in both biological and clinical settings.

Association between B-Myb proto-oncogene and the development of malignant tumors

B-Myb is a critical transcription factor in regulating cell cycle. Dysregulated expression of B-Myb promotes tumor formation and development. B-Myb is a proto-oncogene ubiquitously expressed in proliferating cells, which maintains normal cell cycle progression. It participates in cell apoptosis, tumorigenesis and aging. In addition, B-Myb is overexpressed in several malignant tumors, including breast cancer, lung cancer and hepatocellular carcinoma, and is associated with tumor development. B-Myb expression is also associated with the prognosis of patients with malignant tumors. Both microRNAs and E2F family of transcription factors (E2Fs) contribute to the function of B-Myb. The present review highlights the association between B-Myb and malignant tumors, and offers a theoretical reference for the diagnosis and treatment of malignant tumors.

Integrated Bioinformatics Analysis of the Clinical Value and Biological Function of ATAD2 in Hepatocellular Carcinoma

ATPase family AAA domain-containing protein 2 (ATAD2), a chromatin regulator and an oncogenic transcription cofactor, is frequently overexpressed in many cancers, particularly in hepatocellular carcinoma (HCC). By integrating open-access online mRNA datasets and our institutional tissue data on HCC, the clinical role and functions of ATAD2 were analyzed by bioinformatic algorithms. We systematically examined ATAD2 expression in HCC based on a large sample population, integrating data from our institution and the GEO, Oncomine, and TCGA datasets. Aberrant ATAD2 expression related to pathways was identified by bioinformatic algorithms. The effects of ATAD2 downregulation on the cycle cell were also determined. A pooled analysis from 28 datasets indicated that ATAD2 overexpression was found in HCC (SMD = 8.88, 95% CI: 5.96–11.81, P < 0.001) and was correlated with poor survival. Subgroup analysis of Asian patients with a serum alpha-fetoprotein (AFP) concentration < 200 ng/ml in stage I + II showed that the ATAD2-high group had a more unfavorable overall survival (OS) rate than the ATAD2-low group. The receiver operating characteristic curve indicated that the efficiency of ATAD2 for HCC diagnosis was considerable (area under the curve = 0.89, 95% CI: 0.86–0.91). Functional analysis based on bioinformatic algorithms demonstrated that ATAD2 participates in cell division, mitotic nuclear division, DNA replication, repair, and cell cycle processes. ATAD2 knockout in HCC cells downregulated cyclin C and cyclin D1 protein levels and resulted in G1/S phase arrest in vitro. The kinesin family member C1 (KIFC1), shugoshin 1 (SGO1), GINS complex subunit 1 (GINS1), and TPX2 microtubule nucleation factor (TPX2) genes were closely related to ATAD2 upregulation. ATAD2 may interact with TTK protein kinase (TTK) to accelerate HCC carcinogenesis. ATAD2 plays a vital role in HCC carcinogenesis by disturbing the interaction between chromatin proteins and DNA. Targeting ATAD2 represents a promising method for the development of therapeutic treatments for cancer.

Mutual Balance of Histone Deacetylases 1 and 2 and the Acetyl Reader ATAD2 Regulates the Level of Acetylation of Histone H4 on Nascent Chromatin of Human Cells

Newly synthesized histone H4 that is incorporated into chromatin during DNA replication is acetylated on lysines 5 and 12. Histone deacetylase 1 (HDAC1) and HDAC2 are responsible for reducing H4 acetylation as chromatin matures. Using CRISPR-Cas9-generated hdac1- or hdac2-null fibroblasts, we determined that HDAC1 and HDAC2 do not fully compensate for each other in removing de novo acetyls on H4 in vivo Proteomics of nascent chromatin and proximity ligation assays with newly replicated DNA revealed the binding of ATAD2, a bromodomain-containing posttranslational modification (PTM) reader that recognizes acetylated H4. ATAD2 is a transcription facilitator overexpressed in several cancers and in the simian virus 40 (SV40)-transformed human fibroblast model cell line used in this study. The recruitment of ATAD2 to nascent chromatin was increased in hdac2 cells over the wild type, and ATAD2 depletion reduced the levels of nascent chromatin-associated, acetylated H4 in wild-type and hdac2 cells. We propose that overexpressed ATAD2 shifts the balance of H4 acetylation by protecting this mark from removal and that HDAC2 but not HDAC1 can effectively compete with ATAD2 for the target acetyls. ATAD2 depletion also reduced global RNA synthesis and nascent DNA-associated RNA. A moderate dependence on ATAD2 for replication fork progression was noted only for hdac2 cells overexpressing the protein.

Proteogenomic Characterization of Endometrial Carcinoma

We undertook a comprehensive proteogenomic characterization of 95 prospectively collected endometrial carcinomas, comprising 83 endometrioid and 12 serous tumors. This analysis revealed possible new consequences of perturbations to the p53 and Wnt/β-catenin pathways, identified a potential role for circRNAs in the epithelial-mesenchymal transition, and provided new information about proteomic markers of clinical and genomic tumor subgroups, including relationships to known druggable pathways. An extensive genome-wide acetylation survey yielded insights into regulatory mechanisms linking Wnt signaling and histone acetylation. We also characterized aspects of the tumor immune landscape, including immunogenic alterations, neoantigens, common cancer/testis antigens, and the immune microenvironment, all of which can inform immunotherapy decisions. Collectively, our multi-omic analyses provide a valuable resource for researchers and clinicians, identify new molecular associations of potential mechanistic significance in the development of endometrial cancers, and suggest novel approaches for identifying potential therapeutic targets.

High degree of heterogeneity of PD-L1 and PD-1 from primary to metastatic endometrial cancer

OBJECTIVE

PD-L1 and PD-1 are predictive markers for immunotherapy and increasingly relevant in endometrial cancer. The reported fraction of positive primary tumors has been inconsistent. We investigated the expression of PD-L1 and PD-1 in primary tumors, also stratified by MSI. As immunotherapy is foremost relevant for metastatic disease, PD-L1 and PD-1 expression was also assessed in corresponding metastatic lesions.

METHODS

PD-L1 and PD-1 was investigated in a prospective, population based endometrial cancer cohort of 700 patients with corresponding metastatic lesions from 68 and 74 patients respectively. Fresh tissue was used for gene expression analysis.

RESULTS

In primary tumors, PD-L1 and PD-1 are expressed in 59% and 63%, respectively, but with no impact on survival, nor when stratified for MSS and MSI. Expression patterns of PD-L1 and PD-1 are similar in MSI and MSS tumors. Available metastatic lesions show heterogeneous expression of PD-L1 and PD-1. In gene expression analysis several genes related to immunological activity, including CD274 (encoding for PD-L1), were upregulated in PD-1 positive tumors.

CONCLUSION

PD-L1 and PD-1 are frequently expressed in endometrial cancer and expression patterns are similar across MSS and MSI tumors. Expression in corresponding metastatic lesions is discordant compared to primary tumors. These findings are in particular relevant for treatment decisions in advanced and recurrent disease.

ATAD2 predicts poor outcomes in patients with ovarian cancer and is a marker of proliferation

The oncogene ATPase family AAA domain-containing protein 2 (ATAD2) has been demonstrated to promote malignancy in a number of different types of tumor; however, its expression and role in ovarian cancer (OC) remain unknown. In the present study, it was demonstrated that ATAD2 acts as both a marker and a driver of cell proliferation in OC. Immunohistochemistry (IHC) and bioinformatics analyses were used to evaluate ATAD2 expression in OC, and multi-omics integrated analyses were used to dissect which factor resulted in its upregulation. Multiplex IHC assay was used to reveal the specific expression of ATAD2 in proliferating OC cells. CRISPR-Cas9-mediated gene editing was performed to investigate the effect of ATAD2 deletion on OC proliferation. The results demonstrated that ATAD2 is elevated in primary OC tissues compared with the adjacent normal tissue and metastases from the stomach. Genetic copy number amplification is a primary cause resulting in upregulation of ATAD2, and this was most frequently observed in OC. High ATAD2 expression was associated with advanced progression and predicted an unfavorable prognosis. ATAD2 could be used to identify cases of OC with a high proliferation signature and could label proliferating cells in OC. CRISPR-Cas9-mediated ATAD2 deletion resulted in a significant decrease in both cell proliferation and colony formation ability. Mechanistically, ATAD2-knockdown resulted in deactivation of the mitogen-activated protein kinase (MAPK) pathways, particularly the JNK-MAPK pathway, resulting in suppression of proliferation. Collectively, the data from the present study demonstrated that the ATD2 gene was frequently amplified and protein expression levels were upregulated in OC. Therefore, ATAD2 may serve as an attractive diagnostic and prognostic OC marker, which may be used to identify patients with primary OC, whom are most likely to benefit from ATAD2 gene-targeted proliferation intervention therapies.

Prognostic value of ATPase family, AAA+ domain containing 2 expression in human cancers: A systematic review and meta-analysis

BACKGROUND

ATPase family, AAA+ domain containing 2 (ATAD2) is also known as AAA+ nuclear coregulator cancer-associated protein or PRO2000. ATAD2 has been reported as a prognostic factor in different cancer types, but the association between ATAD2 high expression and survival is still unclear. Thereby, this meta-analysis was performed to evaluate the prognostic value of ATAD2 high expression in human cancers.

METHODS

All of the studies included were retrieved from PubMed, EMBASE, and Cochrane Library electronic databases. The clinical outcomes were evaluated by calculating hazard ratio (HR) with their 95% confidence interval (CI).

RESULTS

Thirteen studies including 2689 patients were eligible for this analysis. The pooled results showed that ATAD2 over-expression was significantly associated with shorter overall survival (OS) (HR = 2.32, 95% CI = 1.77-3.02), as well as shorter recurrence-free survival (RFS), disease-free survival (DFS), and disease-specific survival (DSS) (HR = 1.83, 95% CI = 1.51-2.23) among human cancers. Subgroup analyses for OS were implemented in terms of region, tumor type, and sample size and the results were coincident with overall pooled results. Begg funnel plot and Egger test showed the presence of publication bias for OS. Sensitivity analysis indicated that both results were not affected for removing any study.

CONCLUSION

ATAD2 would be likely to act as a prognostic biomarker for the patients of different cancer types and provide a guide on clinical treatment. Prospective clinical studies are needed to support these findings.

A Novel Set of WNT Pathway Effectors as a Predictive Marker of Uterine Corpus Endometrial Carcinoma-Study Based on Weighted Co-expression Matrices

Uterine corpus endometrial carcinomas (UCEC) are clinically divided into two subgroups-endometrioid endometrial carcinoma (EEC) or non-endometrioid endometrial carcinoma (NEEC). The first group shows relatively better prognosis. However, the discrimination seems to be insufficient due to the fact that in the mildest EEC are patients with poor treatment response and bad prognosis. Our aim was to examine the molecular background of such phenomenon and whether gene expression patterns might be of importance for the clinic. We focused our analysis on WNT pathway target genes since it is one of the main regulators of endometrial proliferation and differentiation. In silico analysis of TCGA data, including Weighted Co-expression Network Analysis, Principle Component Analysis, and Multiple Factor Analysis, allows to select 28 genes that serve as a predictive markers for UCEC patients. Our study revealed that there is a subgroup of the endometrioid cases that molecularly resembles mixed/serous groups. This may explain the reason for existence of subgroup of patients, that although clinically diagnosed with the mildest endometrioid UCEC type, yet present failure in treatment and aggressive course of the disease. Our study suggests that worse outcome in these patients may be based on a disruption of proper WNT signalling pathway resulting in deregulation of its effector genes. Moreover, we showed that mixed group consisting of tumours containing both endometrioid and serous types of cells, has serous expression profile of WNT targets. The proposed gene set allows to predict progression of the disease trough dividing patients into groups of low or high grade with 70.8% sensitivity and 88.6% specificity (AUC = 0.837) as well as could predict patient prognosis associated with UCEC subtype with 70.1% sensitivity and 86.2% specificity (AUC = 0.855). Relatively small number of implicated genes makes it highly applicable and possibly clinically simple and useful tool.

ATAD2 is associated with malignant characteristics of pancreatic cancer cells

Pancreatic cancer is one of the most aggressive human cancers and is associated with a poor prognosis. To develop a novel strategy for pancreatic cancer treatment, it is essential to elucidate the molecular mechanisms underlying the invasion and proliferation of cancer cells. ATPase family AAA domain containing protein 2 (ATAD2) is a highly conserved protein with an AAA+ domain and a bromodomain. Accumulating studies have demonstrated that ATAD2 is associated with the progression of multiple cancers. The present study demonstrated that ATAD2 depletion suppressed cell invasion and migration. In addition, ATAD2 knockdown suppressed anchorage-independent growth of pancreatic cancer cells. Finally, ATAD2 depletion was demonstrated to sensitize pancreatic cancer cells to gemcitabine. The results of the present study indicate that ATAD2 is involved in the malignant characteristics of pancreatic cancer.

Disulfide bridge formation influences ligand recognition by the ATAD2 bromodomain

The ATPase family, AAA domain-containing protein 2 (ATAD2) has a C-terminal bromodomain, which functions as a chromatin reader domain recognizing acetylated lysine on the histone tails within the nucleosome. ATAD2 is overexpressed in many cancers and its expression is correlated with poor patient outcomes, making it an attractive therapeutic target and potential biomarker. We solved the crystal structure of the ATAD2 bromodomain and found that it contains a disulfide bridge near the base of the acetyllysine binding pocket (Cys1057-Cys1079). Site-directed mutagenesis revealed that removal of a free C-terminal cysteine (C1101) residue greatly improved the solubility of the ATAD2 bromodomain in vitro. Isothermal titration calorimetry experiments in combination with the Ellman's assay demonstrated that formation of an intramolecular disulfide bridge negatively impacts the ligand binding affinities and alters the thermodynamic parameters of the ATAD2 bromodomain interaction with a histone H4K5ac peptide as well as a small molecule bromodomain ligand. Molecular dynamics simulations indicate that the formation of the disulfide bridge in the ATAD2 bromodomain does not alter the structure of the folded state or flexibility of the acetyllysine binding pocket. However, consideration of this unique structural feature should be taken into account when examining ligand-binding affinity, or in the design of new bromodomain inhibitor compounds that interact with this acetyllysine reader module.

PIK3CA Amplification Associates with Aggressive Phenotype but Not Markers of AKT-MTOR Signaling in Endometrial Carcinoma

PURPOSE

Amplification of PIK3CA, encoding the PI3K catalytic subunit alpha, is common in uterine corpus endometrial carcinoma (UCEC) and linked to an aggressive phenotype. However, it is unclear whether PIK3CA amplification acts via PI3K activation. We investigated the association between PIK3CA amplification, markers of PI3K activity, and prognosis in a large cohort of UCEC specimens.

EXPERIMENTAL DESIGN

UCECs from 591 clinically annotated patients including 83 tumors with matching metastasis (n = 188) were analyzed by FISH to determine PIK3CA copy-number status. These data were integrated with mRNA and protein expression and clinicopathologic data. Results were verified in The Cancer Genome Atlas dataset.

RESULTS

PIK3CA amplifications were associated with disease-specific mortality and with other markers of aggressive disease. PIK3CA amplifications were also associated with other amplifications characteristic of the serous-like somatic copy-number alteration (SCNA)-high subgroup of UCEC. Tumors with PIK3CA amplification also demonstrated an increase in phospho-p70S6K but had decreased levels of activated phospho-AKT1-3 as assessed by Reverse Phase Protein Arrays and an mRNA signature of MTOR inhibition.

CONCLUSIONS

PIK3CA amplification is a strong prognostic marker and a potential marker for the aggressive SCNA-high subgroup of UCEC. Although PIK3CA amplification associates with some surrogate measures of increased PI3K activity, markers for AKT1-3 and MTOR signaling are decreased, suggesting that this signaling is not a predominant pathway to promote cancer growth of aggressive serous-like UCEC. Moreover, these associations may reflect features of the SCNA-high subgroup of UCEC rather than effects of PIK3CA amplification itself.

Bioinformatic analysis of four miRNAs relevant to metastasis-regulated processes in endometrial carcinoma

BACKGROUND

The purpose of this study was to investigate the expression of different miRNAs in nonmetastatic and metastatic endometrial cancer Existing evidence indicates that there are many factors affecting the metastasis of endometrial cancer, and miRNAs play an unique role in many processes of endometiral cancer.

MATERIALS AND METHODS

miRNA sequences were downloaded from The Cancer Genome Atlas Project database, and Bioinformatics technique was used to deal with those data.

RESULTS

We elucidated the relation between differentially expressed miRNAs and clinical information for a total of 260 tumor tissues and 22 tumor tissues that had metastasized. We used the threshold of P <0.05| log 2 FC | >1.2 to identify potential miRNAs. Four differentially expressed miRNAs were identified in nonmetastatic and metastatic endometrial cancers. Further differential analysis of metastatic tissue revealed that miR-1247 is associated with metastasis of endometrial cancer to the lung, and miR-3200 is associated with the clinical stage of endometrial cancer. A functional enrichment analysis showed that the four miRNAs may be involved in multiple pathways of cancer, including the Wnt, NOTCH, and TGF-β signaling pathways and signaling pathways regulating pluripotency of stem cells. Protein-protein interaction analysis showed that PAK6, SNAP25, MAN1A1, MYB, ZBTB4, UST, ALDH1A3, and NRP2 are hub genes of relevant miRNAs in endometrial cancers.

CONCLUSION

The current study indicates that these four miRNAs may be related to molecular markers of metastasis of endometrial cancer.

ATAD2 silencing decreases VEGFA secretion through targeting has-miR-520a to inhibit angiogenesis in colorectal cancer

ATPase family AAA domain-containing protein 2 (ATAD2) is involved in various types of cancers, including colorectal cancer. This study aimed to determine the role of ATAD2 in angiogenesis in colorectal cancer. Here, we downregulated ATAD2 expression in HCT116 and SW480 cells, and collected the conditioned medium (CM) from control and ATAD2-silenced cells. The effect of CM on human umbilical vein endothelial cells (HUVEC) was evaluated by using CCK-8, wound healing, tube formation, Western blot, and dual-luciferase reporter assays. Our results showed that the proliferation, migration, and tube formation of HUVEC were reduced in presence of ATAD2-silenced CM, and the levels of phosphorylated vascular endothelial growth factor receptor 2 (P-VEGFR2), CD31, and CD34 were downregulated. Mechanism studies showed that ATAD2 silencing regulated the expression of vascular endothelial growth factor A (VEGFA) and miR-520a. Moreover, we found that miR-520a could bind to ATAD2, and its inhibitor partly reversed the alterations in HUVEC induced by CM from ATAD2-silenced cells. In addition, we demonstrated that miR-520a directly bound to 3'-UTR of VEGFA and inhibited its expression. Collectively, our results indicate that ATAD2 inhibition suppresses VEGFA secretion by increasing miR-520a levels. Our study suggests ATAD2 as a potential therapeutic target for angiogenesis in colorectal cancer.

Aneuploidy related transcriptional changes in endometrial cancer link low expression of chromosome 15q genes to poor survival

Aneuploidy is a widely studied prognostic marker in endometrial cancer (EC), however, not implemented in clinical decision-making. It lacks validation in large prospective patient cohorts adjusted for currently standard applied prognostic markers, including estrogen/progesterone receptor status (ER/PR). Also, little is known about aneuploidy-related transcriptional alterations, relevant for understanding its role in EC biology, and as therapeutic target.

We included 825 EC patients with available ploidy status and comprehensive clinicopathologic characterization to analyze ploidy as a prognostic marker. For 144 patients, gene expression data were available to explore aneuploidy-related transcriptional alterations.

Aneuploidy was associated with high age, FIGO stage and grade, non-endometrioid histology, ER/PR negativity, and poor survival (p-values<0.001). In patients with ER/PR negative tumors, aneuploidy independently predicted poor survival (p=0.03), lymph node metastasis (p=0.007) and recurrence (p=0.002). A prognostic ‘aneuploidy signature’, linked to low expression of chromosome 15q genes, was identified and validated in TCGA data.

In conclusion, aneuploidy adds prognostic information in ER/PR negative EC, identifying high-risk patients that could benefit from more aggressive therapies. The ‘aneuploidy signature’ equally identifies these aggressive tumors and suggests a link between aneuploidy and low expression of 15q genes. Integrated analyses point at various dysregulated pathways in aneuploid EC, underlining a complex biology.

Androgen receptor as potential therapeutic target in metastatic endometrial cancer

PURPOSE

The expression and involvement of estrogen (ER) and progesterone receptor (PR) is extensively studied in endometrial cancer. Androgen receptor (AR) is a hormone receptor less studied in female cancers, and we here aim to investigate the expression level of AR in endometrial cancer precursor lesions, primary tumors and metastases, and its potential as therapeutic target.

RESULTS

Expression of AR was observed in 93% of hyperplasias, but only in 41% of non-endometrioid tumors. Compared to estrogen and progesterone receptor AR is more commonly expressed in metastatic lesions, and AR status is discordant in primary and metastatic lesions in a large proportion of cases. AR protein level was significantly associated with survival (P < 0.001), and a calculated AR to ERα ratio identified a subgroup of patients with particular poor outcome. The anti-androgen enzalutamide may have a growth inhibitory effect in endometrial cancer cells based on experiments with primary endometrial tumor cells.

MATERIALS AND METHODS

718 primary endometrial cancers and 298 metastatic lesions (from 142 patients) were investigated for expression of AR in relation to survival, clinical and histopathological data. Protein levels were investigated by immunohistochemistry and reverse phase protein array; mRNA levels by DNA oligonucleotide microarray. The effect of androgen stimulation and inhibition was tested on primary endometrial tumor cells.

CONCLUSIONS

A large proportion of metastatic endometrial cancer lesions express AR, which may be a potential target in these patients. Treatment targeting AR may be of particular benefit in patients with high AR levels compared to ERα levels.

Blocking 17β-hydroxysteroid dehydrogenase type 1 in endometrial cancer: a potential novel endocrine therapeutic approach

The enzyme type 1 17β-hydroxysteroid dehydrogenase (17β-HSD-1), responsible for generating active 17β-estradiol (E2) from low-active estrone (E1), is overexpressed in endometrial cancer (EC), thus implicating an increased intra-tissue generation of E2 in this estrogen-dependent condition. In this study, we explored the possibility of inhibiting 17β-HSD-1 and impairing the generation of E2 from E1 in EC using in vitro, in vivo, and ex vivo models. We generated EC cell lines derived from the well-differentiated endometrial adenocarcinoma Ishikawa cell line and expressing levels of 17β-HSD-1 similar to human tissues. In these cells, HPLC analysis showed that 17β-HSD-1 activity could be blocked by a specific 17β-HSD-1 inhibitor. In vitro, E1 administration elicited colony formation similar to E2, and this was impaired by 17β-HSD-1 inhibition. In vivo, tumors grafted on the chicken chorioallantoic membrane (CAM) demonstrated that E1 upregulated the expression of the estrogen responsive cyclin A similar to E2, which was impaired by 17β-HSD-1 inhibition. Neither in vitro nor in vivo effects of E1 were observed using 17β-HSD-1-negative cells (negative control). Using a patient cohort of 52 primary ECs, we demonstrated the presence of 17β-HSD-1 enzyme activity (ex vivo in tumor tissues, as measured by HPLC), which was inhibited by over 90% in more than 45% of ECs using the 17β-HSD-1 inhibitor. Since drug treatment is generally indicated for metastatic/recurrent and not primary tumor, we next demonstrated the mRNA expression of the potential drug target, 17β-HSD-1, in metastatic lesions using a second cohort of 37 EC patients. In conclusion, 17β-HSD-1 inhibition efficiently blocks the generation of E2 from E1 using various EC models. Further preclinical investigations and 17β-HSD-1 inhibitor development to make candidate compounds suitable for the first human studies are awaited. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Proteomic profiling of endometrioid endometrial cancer reveals differential expression of hormone receptors and MAPK signaling proteins in obese versus non-obese patients

Endometrial cancer development is strongly linked to obesity, but knowledge regarding the influence of excess weight on endometrial tumor signaling pathways remains scarce. We therefore analyzed reverse phase protein array (RPPA) data for obesity-related protein expression patterns, using one training (n=272) and two test cohorts (n=68; n=178) of well-annotated samples from women treated for endometrioid endometrial cancer. Gene expression profiling and immunohistochemistry were used for cross-platform validation. Body mass index (BMI) was significantly correlated with progesterone receptor (PR) expression and a hormone receptor protein signature, across all cohorts. In two of the cohorts, BMI was negatively correlated with RTK- and MAPK-pathway activation, particularly phosphorylated MAPK T202 Y204 (p-MAPK) level. Using stepwise selection modelling, a BMI-associated protein signature, including phosphorylated estrogen receptor α S118 (p-ERα) and p-MAPK, was identified. In the subset of FIGO stage 1, grade 1-2 tumors, obese patients (BMI≥30) had better survival compared to non-obese patients in the two cohorts with longest follow-up time (p=0.042, p=0.058). Non-obese patients had higher p-MAPK levels, whereas obese patients had higher p-ERα levels and enrichment of gene signatures related to estrogen signaling, inflammation, immune signaling and hypoxia. In subgroup analysis of non-obese patients with FIGO stage 1 tumors, low PI3K-activation was associated with reduced survival (p=0.002, training cohort). In conclusion, increasing BMI is associated with increased PR and p-ERα levels and reduced MAPK signaling, both in all patients and in subsets with predicted excellent prognosis. The MAPK-pathway represents a potential therapeutic target in non-obese patients with low stage and low grade tumors.

ATAD2 in cancer: a pharmacologically challenging but tractable target

INTRODUCTION

ATAD2 protein is an emerging oncogene that has strongly been linked to the etiology of multiple advanced human cancers. Therapeutically, despite the fact that genetic suppression/knockdown studies have validated it as a compelling drug target for future therapeutic development, recent druggability assessment data suggest that direct targeting of ATAD2's bromodomain (BRD) may be a very challenging task. ATAD2's BRD has been predicted as a 'difficult to drug' or 'least druggable' target due to the concern that its binding pocket, and the areas around it, seem to be unfeasible for ligand binding. Areas covered: In this review, after shedding light on the multifaceted roles of ATAD2 in normal physiology as well as in cancer-etiology, we discuss technical challenges rendered by ATAD2's BRD active site and the recent drug discovery efforts to find small molecule inhibitors against it. Expert opinion: The identification of a novel low-nanomolar semi-permeable chemical probe against ATAD2's BRD by recent drug discovery campaign has demonstrated it to be a pharmacologically tractable target. Nevertheless, the development of high quality bioavailable inhibitors against ATAD2 is still a pending task. Moreover, ATAD2 may also potentially be utilized as a promising target for future development of RNAi-based therapy to treat cancers.

Asparaginase-like protein 1 is an independent prognostic marker in primary endometrial cancer, and is frequently lost in metastatic lesions

OBJECTIVE

Loss of Asparaginase-like protein 1 (ASRGL1) has been suggested as a prognostic biomarker in endometrial carcinoma. Our objective was to validate this in a prospectively collected, independent patient cohort, and evaluate ASRGL1 expression in endometrial carcinoma precursor lesion and metastases.

METHODS

782 primary endometrial carcinomas, 90 precursor lesions (complex atypical hyperplasia), and 179 metastases (from 87 patients) were evaluated for ASRGL1 expression by immunohistochemistry in relation to clinical and histopathological data. ASRGL1 mRNA level was investigated in 237 primary tumors and related to survival and ASRGL1 protein expression.

RESULTS

Low expression of ASRGL1 protein and ASRGL1 mRNA predicted poor disease specific survival (P<0.001). In multivariate survival analyses ASRGL1 had independent prognostic value both in the whole patient cohort (Hazard ratio (HR): 1.53, 95% confidence interval (CI): 1.04-2.26, P=0.031) and within the endometrioid subgroup (HR: 2.64, CI: 1.47-4.74, P=0.001). Low ASRGL1 expression was less frequent in patients with low grade endometrioid primary tumors compared to high grade endometrioid and non-endometrioid primary tumors, and ASRGL1 was lost in the majority of metastatic lesions.

CONCLUSIONS

In a prospective setting ASRGL1 validates as a strong prognostic biomarker in endometrial carcinoma. Loss of ASRGL1 is associated with aggressive disease and poor survival, and is demonstrated for the first time to have independent prognostic value in the entire endometrial carcinoma patient population.

High visceral fat percentage is associated with poor outcome in endometrial cancer

Despite evidence of increased endometrial cancer (EC) risk in obese women, the impact of obesity on clinical and histological phenotype is poorly understood. This study explored abdominal fat volumes and fat distribution quantified by computed tomography (CT), in relation to tumor characteristics and outcome. 227 EC patients with preoperative abdominal CT scans were included. Total abdominal fat volume (TAV), subcutaneous abdominal fat volume (SAV) and visceral abdominal fat volume (VAV) were quantified, and visceral fat percentage calculated (VAV%=[VAV/TAV]x100). Waist circumference (WC) and liver density (LD) were measured, and body mass index (BMI) calculated. Data for estrogen, progesterone and androgen receptor (ERα/PR/AR) expression by immunohistochemistry were available for 149 tumors, and global gene expression data for 105 tumors. High BMI, TAV, SAV, VAV and WC, and low LD, were associated with low grade endometrioid tumors and PR and AR positivity (all p≤0.03). High VAV% was associated with high age (p<0.001), aneuploidy (p=0.01) and independently predicted reduced disease-specific survival (HR 1.05, 95% CI 1.00-1.11, p=0.041). Tumors from patients with low VAV% showed enrichment of gene sets related to immune activation and inflammation. In conclusion, high VAV% independently predicts reduced EC survival. Tumors arising in patients with low VAV% show enrichment of immune and inflammation related gene sets, suggesting that the global metabolic setting may be important for tumor immune response.

Expression of glucocorticoid receptor is associated with aggressive primary endometrial cancer and increases from primary to metastatic lesions

BACKGROUND

Glucocorticoid receptor (GR) has emerged as an important steroid nuclear receptor in hormone dependent cancers, however few data are available regarding a potential role of GR in endometrial cancer. The aim of this study was to investigate expression of GR in primary and metastatic endometrial cancer lesions, and to assess the relationship between GR expression and clinical and histopathological variables and survival.

METHODS

Expression of GR was investigated by IHC in 724 primary tumors and 289 metastatic lesions (from 135 patients), and correlations with clinical and histopathological data and survival were explored.

RESULTS

Expression of GR was significantly increased in non-endometrioid tumors compared to endometrioid tumors, and was associated with markers of aggressive disease and poor survival both in univariate and multivariate analysis after correcting for age, FIGO stage and histologic grade. Within the subgroups of hormone receptor negative tumors (loss of androgen receptor, estrogen receptor or progesterone receptor) expression of GR was highly significantly associated with poor disease specific survival. There was an overall increase in GR expression from primary to metastatic lesions, and the majority of metastases expressed GR.

CONCLUSION

GR expression in primary endometrial cancer is associated with aggressive disease and poor survival. The majority of metastatic endometrial cancer lesions express GR; therefore GR may represent a therapeutic target in the adjuvant therapy of poor prognosis early-stage as well as metastatic endometrial cancer.

Biological function and histone recognition of family IV bromodomain-containing proteins

Bromodomain proteins function as epigenetic readers that recognize acetylated histone tails to facilitate the transcription of target genes. There are approximately 60 known human bromodomains, which are divided into eight sub-families based on structural conservation. The bromodomain-containing proteins in family IV include seven members (BRPF1, BRPF2, BRPF3, BRD7, BRD9, ATAD2, and ATAD2b). The bromodomains of each of these proteins recognize and bind acetyllysine residues on histone tails protruding from the nucleosome. However, the histone marks recognized by each bromodomain protein can be very different. The BRPF1 subunit of the MOZ histone acetyltransferase (HAT) recognizes acetylated histones H2AK5ac, H4K12ac, H3K14ac, H4K8ac, and H4K5ac. While the bromodomain of BRD7, a member of the SWI/SNF complex, was shown to preferentially recognize acetylated histones H3K9ac, H3K14ac, H4K8ac, H4K12ac, and H4K16ac. The bromodomains of BRPF2 and BRPF3 have similar sequences, and function as part of the HBO1 HAT complex, but there is limited data on which histone ligands they bind. Similarly, there is little known about the histone targets of the BRD9 and ATAD2b bromodomain proteins. Interestingly, the ATAD2 bromodomain was recently shown to preferentially bind to the di-acetylated H4K5acK12ac mark found in newly synthesized histones following DNA replication. However, despite the physiological importance of the family IV bromodomains, little is known about how they function at the molecular or atomic level. In this review, we summarize our understanding of how family IV bromodomains recognize and select for acetyllysine marks and discuss the importance of acetylated histone recognition for their biological functions.

Human germ/stem cell-specific gene TEX19 influences cancer cell proliferation and cancer prognosis

Background

Cancer/testis (CT) genes have expression normally restricted to the testis, but become activated during oncogenesis, so they have excellent potential as cancer-specific biomarkers. Evidence is starting to emerge to indicate that they also provide function(s) in the oncogenic programme. Human TEX19 is a recently identified CT gene, but a functional role for TEX19 in cancer has not yet been defined.

Methods

siRNA was used to deplete TEX19 levels in various cancer cell lines. This was extended using shRNA to deplete TEX19 in vivo. Western blotting, fluorescence activated cell sorting and immunofluorescence were used to study the effect of TEX19 depletion in cancer cells and to localize TEX19 in normal testis and cancer cells/tissues. RT-qPCR and RNA sequencing were employed to determine the changes to the transcriptome of cancer cells depleted for TEX19 and Kaplan-Meier plots were generated to explore the relationship between TEX19 expression and prognosis for a range of cancer types.

Results

Depletion of TEX19 levels in a range of cancer cell lines in vitro and in vivo restricts cellular proliferation/self-renewal/reduces tumour volume, indicating TEX19 is required for cancer cell proliferative/self-renewal potential. Analysis of cells depleted for TEX19 indicates they enter a quiescent-like state and have subtle defects in S-phase progression. TEX19 is present in both the nucleus and cytoplasm in both cancerous cells and normal testis. In cancer cells, localization switches in a context-dependent fashion. Transcriptome analysis of TEX19 depleted cells reveals altered transcript levels of a number of cancer-/proliferation-associated genes, suggesting that TEX19 could control oncogenic proliferation via a transcript/transcription regulation pathway. Finally, overall survival analysis of high verses low TEX19 expressing tumours indicates that TEX19 expression is linked to prognostic outcomes in different tumour types.

Conclusions

TEX19 is required to drive cell proliferation in a range of cancer cell types, possibly mediated via an oncogenic transcript regulation mechanism. TEX19 expression is linked to a poor prognosis for some cancers and collectively these findings indicate that not only can TEX19 expression serve as a novel cancer biomarker, but may also offer a cancer-specific therapeutic target with broad spectrum potential.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0653-4) contains supplementary material, which is available to authorized users.

High mRNA levels of 17β-hydroxysteroid dehydrogenase type 1 correlate with poor prognosis in endometrial cancer

Most endometrial cancers (ECs) are diagnosed at an early stage and have a good prognosis. However, 20-30% develop recurrence and have poor survival. Recurrence-risk prediction at diagnosis is hampered by the scarcity of prognostic markers. Most ECs are estrogen related, and recent studies show that estrogen exposure in EC is controlled intracrinally. We aim at assessing any association between patient prognosis and the pathways controlling the intracrine estrogen generation in EC: (a) the balance between 17β-hydroxysteroid-dehydrogenase-type 1 (HSD17B1), that generates active estrogens, and HSD17B2, converting active into poorly active compounds; (b) the balance between steroid sulphatase (STS, that activates estrogens) and estrogen-sulphotransferase (SULT1E1, that deactivates estrogens); (c) the levels of aromatase (ARO), that converts androgen into estrogens. mRNA levels of HSD17B1, HSD17B2, STS, SULT1E1 and ARO were determined among 175 ECs using cDNA microarray. Proteins were explored by immunohistochemistry. Patients with high mRNA of HSD17B1 had a poorer prognosis compared with those with low levels. Combining the expression of HSD17B1 and HSD17B2, patients with high tumour expression of HSD17B1 and low levels of HSD17B2 had the poorest prognosis. Contrarily, women that had high tumour levels of HSD17B2 and low of HSD17B1 had the best outcome. No differences were seen between mRNA level of other the genes analysed and prognosis. At the protein level, HSD17B2, STS and SULT1E1 were highly expressed, whereas HSD17B1 was low and ARO was almost absent. In conclusion, HSD17B1 is a promising marker to predict EC prognosis. Immunohistochemical detection of this protein in ECs has low sensitivity and should be improved for future clinical applications.