EphA6 promotes angiogenesis and prostate cancer metastasis and is associated with human prostate cancer progression

The pleiotropic nature of NONO, a master regulator of essential biological pathways in cancers

NONO is a member of the Drosophila behavior/human splicing (DBHS) family of proteins. NONO is a multifunctional protein that acts as a "molecular scaffold" to carry out versatile biological activities in many aspects of gene regulation, cell proliferation, apoptosis, migration, DNA damage repair, and maintaining cellular circadian rhythm coupled to the cell cycle. Besides these physiological activities, emerging evidence strongly indicates that NONO-altered expression levels promote tumorigenesis. In addition, NONO can undergo various post-transcriptional or post-translational modifications, including alternative splicing, phosphorylation, methylation, and acetylation, whose impact on cancer remains largely to be elucidated. Overall, altered NONO expression and/or activities are a common feature in cancer. This review provides an integrated scenario of the current understanding of the molecular mechanisms and the biological processes affected by NONO in different tumor contexts, suggesting that a better elucidation of the pleiotropic functions of NONO in physiology and tumorigenesis will make it a potential therapeutic target in cancer. In this respect, due to the complex landscape of NONO activities and interactions, we highlight caveats that must be considered during experimental planning and data interpretation of NONO studies.

Ephs in cancer progression: complexity and context-dependent nature in signaling, angiogenesis and immunity

Eph receptors constitute the largest family of receptor tyrosine kinases, comprising 14 distinct members classified into two subgroups: EphAs and EphBs.. Despite their essential functions in normal physiological processes, accumulating evidence suggests that the involvement of the Eph family in cancer is characterized by a dual and often contradictory nature. Research indicates that Eph/ephrin bidirectional signaling influences cell-cell communication, subsequently regulating cell migration, adhesion, differentiation and proliferation. The contradictory functionalities may arise from the diversity of Eph signaling pathways and the heterogeneity of different cancer microenvironment. In this review, we aim to discuss the dual role of the Eph receptors in tumor development, attempting to elucidate the paradoxical functionality through an exploration of Eph receptor signaling pathways, angiogenesis, immune responses, and more. Our objective is to provide a comprehensive understanding of the molecular mechanisms underlying tumor development. Additionally, we will explore the evolving landscape of utilizing Eph receptors as potential targets for tumor therapy and diagnostic tools.

Engineered Recombinant EGFP-Azurin Theranostic Nanosystem for Targeted Therapy of Prostate Cancer

Erythropoietin-producing hepatocellular (Eph) receptors and their ligands, ephrins, are the largest subfamily of receptor tyrosine kinases (RTKs) that have emerged as a new class of cancer biomarkers due to their aberrant expression in cancer progression. The activation of Eph receptors either due to their hyperexpression or via high affinity binding with their respective ephrin ligands initiates a cascade of signals that impacts cancer development and progression. In prostate cancer, the overexpression of the EphA6 receptor has been correlated with increased metastatic potential. Azurin, a small redox protein, is known to prevent tumor progression by binding to cell surface Eph receptors, inhibiting its autophosphorylation in the kinase domain and thereby disrupting Eph-ephrin signaling. Hence, a self-assembled, theranostic nanosystem of recombinant fusion protein his6EGFP-azu (80-128) was designed by conjugating enhanced green fluorescent protein (EGFP) with the C-terminal region of azurin. This design was inspired by the in silico binding study, where the analogue of ephrinA, his6EGFP-azu (80-128) showed higher binding affinity for the EphA6 receptor than the ephrinA ligands. The his6EGFP-azu (80-128) nanosystem which assembled as nanoparticles was tested for its ability to simultaneously detect and kill the prostate cancer cells, LNCaP. This was achieved by specifically targeting EphA6 receptors overexpressed on the cancer cell surface via C-terminal peptide, azu (80-128). Herein, we report antiproliferative, apoptotic, antimigratory, and anti-invasive effects of this nanosystem on LNCaP cells, while having no similar effects on EphA6 negative human normal lung cells, WI-38.

Multiscale network analysis identifies potential receptors for SARS-CoV-2 and reveals their tissue-specific and age-dependent expression

The coronavirus disease 2019 (COVID-19) pandemic has affected tens of millions of individuals and caused hundreds of thousands of deaths worldwide. Here, we present a comprehensive, multiscale network analysis of the transcriptional response to the virus. In particular, we focused on key regulators, cell receptors, and host processes that were hijacked by the virus for its advantage. ACE2-controlled processes involved CD300e (a TYROBP receptor) as a key regulator and the activation of IL-2 pro-inflammatory cytokine signaling. We further investigated the age dependency of such receptors in different tissues. In summary, this study provides novel insights into the gene regulatory organization during the SARS-CoV-2 infection and the tissue-specific, age-dependent expression of the cell receptors involved in COVID-19.

Signals transduced by Eph receptors and ephrin ligands converge on MAP kinase and AKT pathways in human cancers

Eph receptors, the largest known family of receptor tyrosine kinases, and ephrin ligands have been implicated in a variety of human cancers. The novel bidirectional signaling events initiated by binding of Eph receptors to their cognate ephrin ligands modulate many cellular processes such as proliferation, metastasis, angiogenesis, invasion, and apoptosis. The relationships between the abundance of a unique subset of Eph receptors and ephrin ligands with associated cellular processes indicate a key role of these molecules in tumorigenesis. The combinatorial expression of these molecules converges on MAP kinase and/or AKT/mTOR signaling pathways. The intracellular target proteins of the initial signal may, however, vary in some cancers. Furthermore, we have also described the commonality of up- and down-regulation of individual receptors and ligands in various cancers. The current state of research in Eph receptors illustrates MAP kinase and mTOR pathways as plausible targets for therapeutic interventions in various cancers.

The role of EphA7 in different tumors

Ephrin receptor A7 (EphA7) is a member of the Eph receptor family. It is widely involved in signal transduction between cells, regulates cell proliferation and differentiation, and participates in developing neural tubes and brain. In addition, EphA7 also has a dual role of tumor promoter and tumor suppressor. It can participate in cell proliferation, migration and apoptosis through various mechanisms, and affect tumor differentiation, staging and prognosis. EphA7 may be a potential diagnostic marker and tumor treatment target. This article reviews the effects of EphA7 on a variety of tumor biological processes and pathological characteristics, as well as specific effects and regulatory mechanisms.

Molecular Dynamics Simulation Investigation of the Binding and Interaction of the EphA6-Odin Protein Complex

Protein-protein interaction plays an important role in the development of almost all cells. Elucidating the dynamic binding and affinity of a protein-protein complex is essential for understanding the biological functions of proteins. EphA6 and Odin proteins are members of the Eph (erythropoietin-producing hepatocyte) receptor family and the Anks (ankyrin repeat and sterile α motif domain-containing) family, respectively. Odin significantly functions in regulating endocytosis, degradation, and stability of EphA receptors. In this work, the key residues of the interaction interface were determined through a hydrogen bond, root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), and dynamic correlation analysis of the conventional molecular dynamics (MD) simulations. The calculated standard binding free energy, -7.92 kcal/mol, between EphA6 and Odin is quite consistent with the experimental measurement value, -8.73 kcal/mol. By the combination of several MD simulation techniques, our investigation of the binding process reveals the detailed representative characteristics of the entire binding pathway at the molecular level. Based on the obtained potential of the mean force (PMF) curve, the analysis of the simulation trajectories shows that the residue Arg1013 in the receptor EphA6 is responsible for capturing Asp739 and Asp740 in the ligand Odin during the initial stage of binding. In the later stage of binding, the hydrogen bonds and salt bridges between a series of residues Lys973, Leu1007, Gly1009, His1010, and Arg1012 in the receptor and residues Leu735, Asn736, Asp739, Asp740, and Asp753 in the ligand mainly contribute to the stability of the protein complex. In addition, the specific change process of the receptor-ligand-binding mode is also clarified during the binding process. Our present simulation will promote a deep understanding of the protein-protein interaction, and the identified key interresidue interaction will be theoretical guidance for the design of protein drugs.

ADAM10-cleaved ephrin-A5 contributes to prostate cancer metastasis

A disintegrin and metalloprotease-10(ADAM10) promotes the metastasis of prostate cancer (PCa), but the specific mechanism is indistinct. Herein, DU145 cell lines with stable overexpression and knockdown of ADAM10 were constructed. We found that ectopic expression of ADAM10 not only significantly facilitated cell proliferation, migration, invasion, and inhibited apoptosis, but also could specifically hydrolyze ephrin-A5 and release the ephrin-A5 soluble ectodomain into extracellular media in vitro. These effects were reversed by ADAM10 depletion or treatment of GI254023X. Meanwhile, the co-location and physical interaction among EphA3, ephrin-A5, and ADAM10 were observed in PCa cells using immunofluorescence and immunoprecipitation techniques. Interestingly, overexpression of EphA3 exerted opposite effects in DU145 (ephrin-A5 + ) cells and PC-3 (ephrin-A5 ± ) cells. In addition, the pro-tumor function of EphA3 was reversed by the treatment with the exogenous ephrin-A5-Fc, which increased the phosphorylation level of EphA3 in PC-3 (ephrin-A5 ± ) cells. In nude mice, ADAM10 accelerated growth of the primary tumor, decreased the level of ephrin-A5 in the tumor tissue, but increased the level of ephrin-A5 in the peripheral blood, accompanied with an increase in the expression of CD31 and VEGF (vascular endothelial growth factor) in the tissue. What is more, the serum ephrin-A5 content of patients with metastatic PCa was significantly higher than that of the non-metastatic group (P < 0.05). The receiver operating characteristic curve(ROC) showed that the area under the curve(AUC) of serum ephrin-A5 as a marker of PCa metastasis was 0.843, with a sensitivity of 93.5% and a specificity of 75%. It is concluded that ADAM10-mediated ephrin-A5 shedding promotes PCa metastasis via transforming the role of EphA3 from ligand-dependent tumor suppressor to ligand-independent promoter, and ephrin-A5 in the blood can be used as a new biomarker for PCa metastasis.

Ephrin Receptors (Ephs) Expression in Thymic Epithelial Tumors: Prognostic Implications and Future Therapeutic Approaches

Ephrin receptors (Ephs) are receptor tyrosine kinases (RTKs) implicated in tissue development and homeostasis, and they are aberrantly expressed in tumors. Here, immunohistochemical Eph type-A and -B expression in thymic epithelial tumors (TETs) was assessed and correlated with clinicopathological parameters. Tissue microarrays from 98 TETs were stained for EphA1, -A2, -A4 -A6, -B1, -B2, -B4 and -B6. The relationship between neoplastic and lymphoid cell immunoreactivity score (H-score), histopathological parameters (Pearson’s test) and survival of 35 patients (Mantel-Cox model) was explored. Epithelial-rich subtypes showed higher EphA6 cytoplasmic H-score (B2/B3, carcinoma) (p < 0.001) and stronger EphA4 H-score (B3, carcinoma) (p = 0.011). The immature T-cells, especially in subtypes AB/B1, had higher EphB6 H-score than carcinoma-associated mature lymphocytes (p < 0.001); carcinomas had higher lymphocytic EphB1 H-score (p = 0.026). Higher lymphocytic and lower epithelial EphB6 H-score correlated with Masaoka stage ≤II (p = 0.043, p = 0.010, respectively). All cases showed variable epithelial and lymphocytic EphA2 expression, but clinicopathological associations were not reached. Our study confirmed that Eph type-A and -B expression in TETs is associated with established prognostic parameters, i.e., tumor subtype and Masaoka stage, although correlation with patient survival was not reached. Such findings suggest involvement of these RTKs in thymic neoplasia, as well as their potential utility as treatment targets.

The Clinical Impact of the EPH/Ephrin System in Cancer: Unwinding the Thread

Erythropoietin-producing human hepatocellular receptors (EPHs) compose the largest known subfamily of receptor tyrosine kinases (RTKs). They bind and interact with the EPH family receptor interacting proteins (ephrins). EPHs/ephrins are implicated in a variety of physiological processes, as well as in cancer pathogenesis. With neoplastic disease remaining a leading cause of death world-wide, the development of novel biomarkers aiding in the field of diagnosis, prognosis, and disease monitoring is of utmost importance. A multitude of studies have proven the association between the expression of members of the EPH/ephrin system and various clinicopathological parameters, including disease stage, tumor histologic grade, and patients' overall survival. Besides their utilization in timely disease detection and assessment of outcome, EPHs/ephrins could also represent possible novel therapeutic targets. The aim of the current review of the literature was to present the existing data regarding the association between EPH/ephrin system expression and the clinical characteristics of malignant tumors.

Identification of a 5-Gene-Based Scoring System by WGCNA and LASSO to Predict Prognosis for Rectal Cancer Patients

Background

Although accumulating evidence suggested that a molecular signature panel may be more effective for the prognosis prediction than routine clinical characteristics, current studies mainly focused on colorectal or colon cancers. No reports specifically focused on the signature panel for rectal cancers (RC). Our present study was aimed at developing a novel prognostic signature panel for RC.

Methods

Sequencing (or microarray) data and clinicopathological details of patients with RC were retrieved from The Cancer Genome Atlas (TCGA-READ) or the Gene Expression Omnibus (GSE123390, GSE56699) database. A weighted gene coexpression network was used to identify RC-related modules. The least absolute shrinkage and selection operator analysis was performed to screen the prognostic signature panel. The prognostic performance of the risk score was evaluated by survival curve analyses. Functions of prognostic genes were predicted based on the interaction proteins and the correlation with tumor-infiltrating immune cells. The Human Protein Atlas (HPA) tool was utilized to validate the protein expression levels.

Results

A total of 247 differentially expressed genes (DEGs) were commonly identified using TCGA and GSE123390 datasets. Brown and yellow modules (including 77 DEGs) were identified to be preserved for RC. Five DEGs (ASB2, GPR15, PRPH, RNASE7, and TCL1A) in these two modules constituted the optimal prognosis signature panel. Kaplan-Meier curve analysis showed that patients in the high-risk group had a poorer prognosis than those in the low-risk group. Receiver operating characteristic (ROC) curve analysis demonstrated that this risk score had high predictive accuracy for unfavorable prognosis, with the area under the ROC curve of 0.915 and 0.827 for TCGA and GSE56699 datasets, respectively. This five-mRNA classifier was an independent prognostic factor. Its predictive accuracy was also higher than all clinical factor models. A prognostic nomogram was developed by integrating the risk score and clinical factors, which showed the highest prognostic power. ASB2, PRPH, and GPR15/TCL1A were predicted to function by interacting with CASQ2/PDK4/EPHA67, PTN, and CXCL12, respectively. TCL1A and GPR15 influenced the infiltration levels of B cells and dendritic cells, while the expression of PRPH was positively associated with the abundance of macrophages. HPA analysis supported the downregulation of PRPH, RNASE7, CASQ2, EPHA6, and PDK4 in RC compared with normal controls.

Conclusion

Our immune-related signature panel may be a promising prognostic indicator for RC.

The Role of the Eph Receptor Family in Tumorigenesis

Simple Summary

The Eph receptor family is implicated in both tumour promotion and suppression, depending on the tissue-specific context of available receptor interactions with ligands, adaptor proteins and triggered downstream signalling pathways. This complex interplay has not only consequences for tumorigenesis but also offers a basis from which new cancer-targeting strategies can be developed. This review comprehensively summarises the current knowledge of Eph receptor implications in oncogenesis in a tissue- and receptor-specific manner, with the aim to develop a better understanding of Eph signalling pathways for potential targeting in novel cancer therapies.

Abstract

The Eph receptor tyrosine kinase family, activated by binding to their cognate ephrin ligands, are important components of signalling pathways involved in animal development. More recently, they have received significant interest due to their involvement in oncogenesis. In most cases, their expression is altered, affecting the likes of cell proliferation and migration. Depending on the context, Eph receptors have the potential to act as both tumour promoters and suppressors in a number of cancers, such as breast cancer, colorectal cancer, lung cancer, prostate cancer, brain cancer and Kaposi’s sarcoma (KS), the latter being intrinsically linked to EphA2 as this is the receptor used for endothelial cell entry by the Kaposi’s sarcoma-associated herpesvirus (KSHV). In addition, EphA2 deregulation is associated with KS, indicating that it has a dual role in this case. Associations between EphA2 sequence variation and KSHV infection/KS progression have been detected, but further work is required to formally establish the links between EphA2 signalling and KS oncogenesis. This review consolidates the available literature of the role of the Eph receptor family, and particularly EphA2, in tumorigenesis, with the aim to develop a better understanding of Eph signalling pathways for potential targeting in novel cancer therapies.

Interactions Between lncRNA TUG1 and miR-9-5p Modulate the Resistance of Breast Cancer Cells to Doxorubicin by Regulating eIF5A2

Purpose

Breast cancer (BC) is one of the leading causes of cancer-related deaths. Chemoresistance of BC remains a major unmet clinical obstacle. TUG1 (taurine-upregulated gene 1), a long noncoding RNA (lncRNA), and microRNAs (miRNA) are implicated in therapeutic resistance. However, the interactions between TUG1 and miRNAs that regulate doxorubicin (Dox) resistance in BC remain elusive.

Materials and Methods

Expression of TUG1 and miR-9 was measured by real-time PCR. EIF5A2 (eukaryotic translation initiation factor 5A-2) was detected by Western blot. Transfection of siRNAs or miRNA inhibitors was applied to silence lncRNA TUG1, eIF5A2 or miR-9. Cell viability, proliferation, and apoptosis were determined by CCK-8 (cell counting kit-8), flow cytometry, and EdU (5-ethynyl-2ʹ-deoxyuridine) assays, respectively. The regulatory relationship between TUG1 and miR-9 was determined by a luciferase assay.

Results

LncRNA TUG1 was highly expressed in BC tissues and positively associated with Dox resistance in BC cell lines. SiRNA knockdown of TUG1 reversed Dox resistance in MCF-7/ADR cells. Mechanistically, TUG1 acted as a “sponge” for miR-9 and downregulated miR-9. Treatment with a miR-9 inhibitor blocked the effect of TUG1 siRNA, and knockdown of TUG1 inhibited the effects of miR-9. Furthermore, TUG1 inhibition of apoptosis induced by Dox involved miR-9 targeting of eIF5A2.

Conclusion

TUG1 modulates the susceptibility of BC cells to Dox by regulating the expression of eIF5A2 via interacting with miR-9. These results indicate that the lncRNA TUG1 may be a novel therapeutic target in breast cancer.

Diabetic nephropathy alters circulating long noncoding RNA levels that normalize following simultaneous pancreas-kidney transplantation

Simultaneous pancreas-kidney transplantation (SPKT) replaces kidney function and restores endogenous insulin secretion in patients with diabetic nephropathy (DN). Here, we aimed to identify circulating long noncoding RNAs (lncRNAs) that are associated with DN and vascular injury in the context of SPKT. Based on a pilot study and a literature-based selection of vascular injury-related lncRNAs, we assessed 9 candidate lncRNAs in plasma samples of patients with diabetes mellitus with a kidney function >35 mL/min/1.73 m² (DM; n = 12), DN (n = 14), SPKT (n = 35), healthy controls (n = 15), and renal transplant recipients (KTx; n = 13). DN patients were also studied longitudinally before and 1, 6, and 12 months after SPKT. Of 9 selected lncRNAs, we found MALAT1, LIPCAR, and LNC-EPHA6 to be higher in DN compared with healthy controls. SPKT caused MALAT1, LIPCAR, and LNC-EPHA6 to normalize to levels of healthy controls, which was confirmed in the longitudinal study. In addition, we observed a strong association between MALAT1, LNC-EPHA6, and LIPCAR and vascular injury marker soluble thrombomodulin and a subset of angiogenic microRNAs (miR-27a, miR-130b, miR-152, and miR-340). We conclude that specific circulating lncRNAs associate with DN-related vascular injury and normalize after SPKT, suggesting that lncRNAs may provide a promising novel monitoring strategy for vascular integrity in the context of SPKT.

Functional genomic analysis identifies drug targetable pathways in invasive and metastatic cutaneous squamous cell carcinoma

Although cutaneous squamous cell carcinoma (cSCC) is treatable in the majority of cases, deadly invasive and metastatic cases do occur. To date there are neither reliable predictive biomarkers of disease progression nor FDA-approved targeted therapies as standard of care. To address these issues, we screened patient-derived primary cultured cells from invasive/metastatic cSCC with 107 small-molecule inhibitors. In-house bioinformatics tools were used to cross-analyze drug responses and DNA mutations in tumors detected by whole-exome sequencing (WES). Aberrations in molecular pathways with evidence of potential drug targets were identified, including the Eph-ephrin and neutrophil degranulation signaling pathways. Using a screening panel of siRNAs, we identified EPHA6 and EPHA7 as targets within the Eph-ephrin pathway responsible for mitigating decreased cell viability. These studies form a plausible foundation for detecting biomarkers of high-risk progressive disease applicable in dermatopathology and for patient-specific therapeutic options for invasive/metastatic cSCC.

Circulating Long Noncoding RNA LNC-EPHA6 Associates with Acute Rejection after Kidney Transplantation

Acute rejection (AR) of a kidney graft in renal transplant recipients is associated with microvascular injury in graft dysfunction and, ultimately, graft failure. Circulating long noncoding RNAs (lncRNAs) may be suitable markers for vascular injury in the context of AR. Here, we first investigated the effect of AR after kidney transplantation on local vascular integrity and demonstrated that the capillary density markedly decreased in AR kidney biopsies compared to pre-transplant biopsies. Subsequently, we assessed the circulating levels of four lncRNAs (LNC-RPS24, LNC-EPHA6, MALAT1, and LIPCAR), that were previously demonstrated to associate with vascular injury in a cohort of kidney recipients with a stable kidney transplant function (n = 32) and recipients with AR (n = 15). The latter were followed longitudinally six and 12 months after rejection. We found higher levels of circulating LNC-EPHA6 during rejection, compared with renal recipients with a stable kidney function (p = 0.017), that normalized one year after AR. In addition, LNC-RPS24, LNC-EPHA6, and LIPCAR levels correlated significantly with the vascular injury marker soluble thrombomodulin. We conclude that AR and microvascular injury are associated with higher levels of circulating LNC-EPHA6, which emphasizes the potential role of lncRNAs as biomarker in the context of AR.

Knockdown of GSG2 inhibits prostate cancer progression in vitro and in vivo

Prostate cancer (PCa) is the second leading cause of cancer‑related death among men worldwide. The present study aimed to investigate the role of germ cell‑specific gene 2 protein (GSG2), also termed histone H3 phosphorylated by GSG2 at threonine‑3, in the development and progression of PCa. GSG2 expression levels in PCa tissues and para‑carcinoma tissues was detected by immunohistochemistry. The GSG2 knockdown cell model was constructed by lentivirus infection, and the knockdown efficiency was verified by qPCR and WB. In addition, the effects of shGSG2 on cell proliferation, colony formation and apoptosis were evaluated by Celigo cell counting assay, Giemsa staining and flow cytometry, respectively. Tumor development in nude mice was also detected. GSG2 expression was upregulated in PCa tissues and human PCa cell lines PC‑3 and DU 145. High expression of GSG2 in tumor samples was associated with progressed tumors. GSG2 knockdown suppressed cell proliferation and colony formation, but promoted apoptosis, which was also verified in vivo. The results of the present study revealed that GSG2 upregulation was associated with PCa progression; GSG2 knockdown inhibited cell proliferation and colony formation and induced apoptosis, and may therefore serve as a potential therapeutic target for PCa therapy.

The role of Eph receptors in cancer and how to target them: novel approaches in cancer treatment

INTRODUCTION

Erythropoietin-producing human hepatocellular (Eph) receptors are among the largest family of tyrosine kinases that are divided into two classes: EphA and EphB receptors. Over the past two decades, their role in cancer has become more evident.

AREAS COVERED

There is a need for new anticancer treatments and more insight in the emerging role of Eph receptors in cancer. Molecular mechanisms underlying the pro-tumorigenic effects of Eph receptors could be exploited for future therapeutic strategies. This review describes the variability in expression levels and different effects on oncogenic and tumor suppressive downstream signaling of Eph receptors in various cancer types, and the small molecules, antibodies and peptides that target these receptors.

EXPERT OPINION

The complexity of Eph signaling is a challenge for the definition of clear targets for cancer treatment. Nevertheless, numerous drugs that target EphA2 and EphB4 are currently in clinical trials. However, some Eph targeted drugs also inhibit other tyrosine kinases, so it is unclear to what extent the targeting of Eph receptors contributes to their efficacy. Future research is warranted for an improved understanding of the full network in which Eph receptors function. This will be critical for the improvement of the anticancer effects of drugs that target the Eph receptors.

Defining a role for lung function associated gene GSTCD in cell homeostasis

Genome wide association (GWA) studies have reproducibly identified signals on chromosome 4q24 associated with lung function and COPD. GSTCD (Glutathione S-transferase C-terminal domain containing) represents a candidate causal gene in this locus, however little is currently known about the function of this protein. We set out to further our understanding of the role of GSTCD in cell functions and homeostasis using multiple molecular and cellular approaches in airway relevant cells. Recombinant expression of human GSTCD in conjunction with a GST activity assay did not identify any enzymatic activity for two GSTCD isoforms questioning the assignment of this protein to this family of enzymes. Protein structure analyses identified a potential methyltransferase domain contained within GSTCD, with these enzymes linked to cell viability and apoptosis. Targeted knockdown (siRNA) of GSTCD in bronchial epithelial cells identified a role for GSTCD in cell viability as proliferation rates were not altered. To provide greater insight we completed transcriptomic analyses on cells with GSTCD expression knocked down and identified several differentially expressed genes including those implicated in airway biology; fibrosis e.g. TGFBR1 and inflammation e.g. IL6R. Pathway based transcriptomic analyses identified an over-representation of genes related to adipogenesis which may suggest additional functions for GSTCD. These findings identify potential additional functions for GSTCD in the context of airway biology beyond the hypothesised GST activity and warrant further investigation.

Eukaryotic translation initiation factor 5A2 is highly expressed in prostate cancer and predicts poor prognosis

Eukaryotic translation initiation factor (EIF) 5A2 exerts important functions that regulate the development and progression of cancers. The present study aimed to investigate the expression of EIF5A2 in prostate cancer (PCa) and its association with biological and prognostic significance. EIF5A2 mRNA and protein levels were analyzed in three paired samples of freshly resected PCa and adjacent non-tumor tissues. Immunohistochemical staining was used to detect the expression of EIF5A2 protein levels in 72 paraffin-embedded PCa tumor specimens. Subsequently, the association between EIF5A2 protein expression and clinicopathological parameters was assessed. Semi-quantitative reverse transcription-polymerase chain reaction and western blot analyses showed both EIF5A2 mRNA and protein levels were elevated in PCa compared with adjacent non-tumor tissues. Elevated EIF5A2 protein levels were observed in 73.6% (53/72) of the clinical PCa tissues using immunohistochemical staining. EIF5A2 expression was significantly associated with tumor stage (P=0.011) and biochemical recurrence status (P=0.032). Additionally, high levels of EIF5A2 predicted worse progression-free survival (P=0.007). Multivariate Cox regression analysis indicated that high expression of EIF5A2 was an independent prognostic factor for poor progression-free survival (hazard ratios, 0.366; 95% confidence interval, 0.349-0.460; P=0.021). The present study demonstrated that EIF5A2 is overexpressed in prostate cancer and may be a potential predictor and therapeutic target in PCa patients.

GABARAPL1 suppresses metastasis by counteracting PI3K/Akt pathway in prostate cancer

Metastasis remains the primary cause of prostate cancer (CaP)-related death. Using a genome wide shRNA screen, we identified GABARAPL1 as a potential CaP metastasis suppressor. GABARAPL1 mRNA levels inversely correlate with the invasive potential of a panel of human CaP cell lines. Lower mRNA levels correlate with higher Gleason scores in clinical CaP tumor samples. Moreover, Kaplan-Meier curves analysis showed that GABARAPL1 down-regulation in cancer tissues is associated with decreased disease-free survival in CaP patients. Knockdown of GABARAPL1 in human LNCaP cells results in increased invasion in vitro and lymph node metastasis in vivo. Vice versa, ectopic expression of GABARAPL1 decreases the invasiveness of CWR22Rv1 cells. Our previous in vitro shRNA screening identified FOXO4, a PI3K/Akt-inactivating downstream target, as a potential CaP metastasis suppressor. We show here that silencing FOXOs leads to reduced GABARAPL1 expression and enhanced invasion in LNCaP cells. Transfection of constitutively-activated Akt (myr-Akt) increased the invasion of LNCaP cells, which is associated with the inactivation of FOXOs and decreased GABARAPL1 expression. Indeed, forced expression of GABARAPL1 reversed the increased invasiveness of LNCaP/myr-Akt cells. Finally, immunohistochemistry analysis shows that Akt phosphorylation is negatively correlated with GABARAPL1 expression in human CaP tissues. Taken together, our data indicate that the suppression of FOXOs-GABARAPL1 signaling by Akt is an important mechanism for CaP progression and metastasis.

Erythropoietin-producing hepatocellular A6 overexpression is a novel biomarker of poor prognosis in patients with breast cancer

Erythropoietin-producing hepatocellular A6 (EphA6) is a member of the Eph receptor tyrosine kinase family, which has been implicated in tumorigenesis. However, little is known about the expression and function of EphA6 in breast cancer. The aim of the present study was to investigate the expression of EphA6 and the possible association between EphA6 and clinicopathological characteristics in breast cancer. In the present study, EphA6 mRNA expression was measured in 26 paired breast cancer tissues and adjacent non-cancerous tissues by reverse transcription-quantitative polymerase chain reaction. Additionally, the protein expression of EphA6 in breast cancer tissues from 116 patients was examined by immunohistochemistry, and the prognostic value for patients with breast cancer was evaluated. The results of the present study indicated that EphA6 mRNA and protein expression in breast cancer was significantly higher than that in adjacent non-cancerous tissues (P<0.001). EphA6 overexpression was significantly associated with a high histological grade (P<0.001), overexpression of human epidermal growth factor 2 (HER-2; P=0.0106), low estrogen receptor expression (P=0.0247) and low progesterone receptor expression (P=0.0015). Furthermore, the increased expression of EphA6 was demonstrated to be associated with breast cancer subtypes (P=0.0164). Kaplan-Meier curves demonstrated that high EphA6 expression was associated with lower overall survival rates in patients with breast cancer (P=0.015). Univariate and multivariate analysis revealed that high EphA6 expression, Tumor-Node-Metastasis classification and subtype were independent prognostic factors for patients with breast cancer (all P<0.05). In conclusion, EphA6 may serve an important role in breast carcinogenesis and may pose as a novel prognostic indicator and therapeutic target for breast cancer, particularly in patients with steroid receptor negative expression and HER-2 overexpression.

Knockdown of EIF5A2 inhibits the malignant potential of non-small cell lung cancer cells

Eukaryotic translation initiation factor 5A2 (EIF5A2) has been demonstrated to be upregulated in numerous types of human cancer and is associated with cancer progression. However, the expression and role of EIF5A2 in non-small cell lung cancer (NSCLC) remains unclear. In the present study, the role of EIF5A2 in NSCLC was investigated, in addition to the underlying molecular mechanisms by which EIF5A2 acts. Relative EIF5A2 expression levels were determined in NSCLC cells and compared with levels in non-cancerous lung tissues. Short interfering (si)RNA targeted against EIF5A2 was used to knock down EIF5A2 levels in NSCLC cells. Cell proliferation, apoptosis rate, migration ability and invasion ability were determined in untreated and siRNA-treated NSCLC cells, in addition to the relative protein expression levels of various tumorigenic proteins and E-cadherin. EIF5A2 expression was significantly higher in NSCLC tissues compared with adjacent normal tissues. Knockdown of EIF5A2 in the NSCLC cells significantly inhibited cell proliferation and induced apoptosis. Furthermore, EIF5A2 silencing suppressed cell migratory and invasive capacities in vitro. Silencing of EIF5A2 in the NSCLC cells resulted in the downregulation of the tumorigenic proteins, apoptosis regulator Bcl-2 and myc proto-oncogene protein, and upregulation of E-cadherin, suggesting that EIF5A2 promotes proliferation and metastasis through these proteins. EIF5A2 may therefore serve as a novel therapeutic target for the treatment of NSCLC.

EphB6 overexpression and Apc mutation together promote colorectal cancer

The erythropoietin-producing hepatocyte (Eph) family tyrosine kinases play important roles in tumorigenesis and cancer aggression. In this study, we investigated the role of EphB6 in oncogenic transformation of colorectal epithelial cells in vitro and in vivo. EphB6 is upregulated in human colorectal cancer (CRC) tissues as compared to normal tissues, and its overexpression promotes proliferation, migration and invasion by IMCE colorectal adenoma cells, in which one Apc allele is mutated. EphB6 overexpression together with Apc mutation leads to the development of colorectal tumors in vivo. Expression microarrays using mRNAs and lncRNAs isolated from EphB6-overexpresssing IMCE and control cells revealed a large number of dysregulated genes involved in cancer-related functions and pathways. The present study is the first to demonstrate that EphB6 overexpression together with Apc gene mutations may enhance proliferation, invasion and metastasis by colorectal epithelial cells. Microarray data and pathway analysis of differentially expressed genes provided insight into possible EphB6-regulated mechanisms promoting tumorigenesis and cancer progression. EphB6 overexpression may represent a novel, effective biomarker predictive of cell proliferation, invasion and metastasis patterns in CRC tumors.

Overexpression of p54nrb/NONO induces differential EPHA6 splicing and contributes to castration-resistant prostate cancer growth

The non-POU domain-containing octamer binding protein p54^nrb/NONO is a multifunctional nuclear protein involved in RNA splicing, processing, and transcriptional regulation of nuclear hormone receptors. Through chromosome copy number analysis via whole-exome sequencing, we revealed amplification of the chromosome Xq11.22-q21.33 locus containing the androgen receptor (AR) and NONO genes in androgen-independent, castration-resistant prostate cancer (CRPC)-like LNCaP-SF cells. Moreover, NONO was frequently amplified and overexpressed in patients with CRPC. RNA sequencing data revealed that a truncated ephrin type-A receptor 6 (EPHA6) splice variant (EPHA6-001) was overexpressed in LNCaP-SF cells, and knockdown of NONO or EPHA6-001 prevented EPHA6-001 expression and reduced proliferation and invasion by LNCaP-SF cells grown under androgen deprivation conditions. Growth inhibition and differential splicing of EPHA6 mRNA by p54^nrb/NONO were confirmed in gene silencing experiments in 22Rv1 PCa cells. Importantly, NONO knockdown in LNCaP-SF cells led to reduced tumor growth in castrated mice. These findings indicate that p54^nrb/NONO is amplified and overexpressed in CRPC cells and clinical samples, and facilitates CRPC growth by mediating aberrant EPHA6 splicing. We therefore propose that p54^nrb/NONO constitutes a novel and attractive therapeutic target for CRPC.

MicroRNAs in cancer metastasis and angiogenesis

Cancer metastasis is a malignant process by which tumor cells migrate from their primary site of origin to other organs. It is the main cause of poor prognosis in cancer patients. Angiogenesis is the process of generating new blood capillaries from pre-existing vasculature. It plays a vital role in primary tumor growth and distant metastasis. MicroRNAs are small non-coding RNAs involved in regulating normal physiological processes as well as cancer pathogenesis. They suppress gene expression by specifically binding to the 3′-untranslated region (3′-UTR) of their target genes. They can thus act as oncogenes or tumor suppressors depending on the function of their target genes. MicroRNAs have shown great promise for use in anti-metastatic cancer therapy. In this article, we review the roles of various miRNAs in cancer angiogenesis and metastasis and highlight their potential for use in future therapies against metastatic cancer.

Molecular determinants of prostate cancer metastasis

Metastatic cancer remains largely incurable and fatal. The general course of cancer, from the initiation of primary tumor formation and progression to metastasis, is a multistep process wherein tumor cells at each step must display specific phenotypic features. Distinctive capabilities required for primary tumor initiation and growth form the foundation, and sometimes may remain critical, for subsequent metastases. These phenotypic features must remain easily malleable during the acquisition of additional capabilities unique and essential to the metastatic process such as dissemination to distant tissues wherein tumor cells interact with foreign microenvironments. Thus, the metastatic phenotype is a culmination of multiple genetic and epigenetic alterations and subsequent selection for favorable traits under the pressure of ever-changing tumor microenvironments. Although our understanding of the molecular programs that drive cancer metastasis are incomplete, increasing evidence suggests that successful metastatic colonization relies on the dissemination of cancer stem cells (CSCs) with tumor-regenerating capacity and adaptive programs for survival in distant organs. In the past 2-3 years, a myriad of novel molecular regulators and determinants of prostate cancer metastasis have been reported, and in this Perspective, we comprehensively review this body of literature and summarize recent findings regarding cell autonomous molecular mechanisms critical for prostate cancer metastasis.

Ligand-dependent EphA7 signaling inhibits prostate tumor growth and progression

The downregulation of receptor tyrosine kinase EphA7 is frequent in epithelial cancers and linked to tumor progression. However, the detailed mechanism of EphA7-mediated prostate tumor progression remains elusive. To test the role of EphA7 receptor in prostate cancer (PCa) progression directly, we generated EphA7 receptor variants that were either lacking the cytoplasmic domain or carrying a point mutation that inhibits its phosphorylation by site-directed mutagenesis. Overexpression of wild-type (WT) EphA7 in PCa cells resulted in decreased tumor volume and increased tumor apoptosis in primary tumors. In addition, ectopic expression of WT EphA7 both can delay PCa cell proliferation and could inhibit PCa cell migration and invasion. This protein can also induce PCa cell apoptosis that correlated with increasing the protein expression levels of Bax, elevating the caspase-3 activities, reducing the protein expression levels of Bcl-2 and facilitating the dephosphorylation of Akt, which is further increased by the stimulation of ephrinA5-Fc. However, expression of these EphA7 mutants in PCa cells has no effect in vivo and in vitro. The expression of EphA7 and ephrinA5 was significantly decreased in PCa specimens compared with BPH tissues or paired normal tissues. Moreover, the phosphorylation of EphA7 was positively related with ephrinA5 expression in human prostate tissues. In sum, receptor phosphorylation of EphA7, at least in part, suppress PCa tumor malignancy through targeting PI3K/Akt signaling pathways.

Androgen-deprivation therapy with enzalutamide enhances prostate cancer metastasis via decreasing the EPHB6 suppressor expression

Early studies suggested that using ADT with the recently developed anti-androgen Enzalutamide (Enz, also named as MDV3100 could extent castration resistant prostate cancer (CRPC) patients' survival an extra 4.8 months. Yet the therapy in most patients might eventually fail due to development of Enz-resistance. Here we found Enz might also increase some unwanted side-effects via increasing the CRPC cell invasion that might involve altering the Enz-mediated androgen receptor (AR)/EPHB6 suppressor/JNK signaling. Results from multiple clinical surveys also indicated that EPHP6 might function as a suppressor of PCa metastasis. Mechanism dissection revealed that Enz-mediated AR might function via binding to the androgen-response-element (ARE) on the EPHB6 promoter to decrease EPHB6 suppressor expression, which might then activate the phosphorylation of JNK signals to increase the CRPC cell invasion. Targeting this newly identified AR/EPHB6/JNK signaling with JNK inhibitor (SP600125) may then block/reverse the Enz-increased CRPC cell invasion. Collectively, our results suggest that Enz may increase CRPC cell invasion via altering the AR/EPHB6/JNK/MMP9 signaling and targeting this newly identified signaling may help us to increase the Enz efficacy to better suppress the CRPC at the later metastatic stage.

Breast Carcinoma: From Initial Tumor Cell Detachment to Settlement at Secondary Sites

Metastasis represents a multistep cascade of cancer cell alterations accompanied by structural and functional changes within the tumor microenvironment which may involve the induction of a retrodifferentiation program. Major steps in metastatic developments include (A) cell detachment from the primary tumor site involving epithelial-mesenchymal transition (EMT), (B) migration and invasion into surrounding tissue, (C) transendothelial intravasation into the vasculature of blood and/or lymphatic vessels as circulating tumor cells (CTCs), (D) dissemination to distant organs, and (E) extravasation of CTCs to secondary sites as disseminated tumor cells (DTCs). This article highlights some aspects of the metastatic cascade with a focus on breast cancer cells. Metastatic steps critically depend on the capability of cancer cells to adapt to distant tissues and the corresponding new microenvironment. As a consequence, increasing plasticity and developmental changes paralleled by acquisition of new cancer cell functionalities challenge a successful therapeutic approach.

Microbial Signatures Associated with Oropharyngeal and Oral Squamous Cell Carcinomas

The microbiome is fundamentally one of the most unique organs in the human body. Dysbiosis can result in critical inflammatory responses and result in pathogenesis contributing to neoplastic events. We used a pan-pathogen array technology (PathoChip) coupled with next-generation sequencing to establish microbial signatures unique to human oral and oropharyngeal squamous cell carcinomas (OCSCC/OPSCC). Signatures for DNA and RNA viruses including oncogenic viruses, gram positive and negative bacteria, fungi and parasites were detected. Cluster and topological analyses identified 2 distinct groups of microbial signatures related to OCSCCs/OPSCCs. Results were validated by probe capture next generation sequencing; the data from which also provided a comprehensive map of integration sites and chromosomal hotspots for micro-organism genomic insertions. Identification of these microbial signatures and their integration sites may provide biomarkers for OCSCC/OPSCC diagnosis and prognosis as well as novel avenues for study of their potential role in OCSCCs/OPSCCs.

Comprehensive study of angiogenic factors in women with endometriosis compared to women without endometriosis

OBJECTIVE

Endometriosis is a benign gynaecological disease, affecting women during their reproductive years. Angiogenesis represents a crucial step in the pathogenesis of endometriosis, because endometriotic lesions require neovascularization. In this study several angiogenesis-related genes have been studied in the context of endometriosis. Some of the analyzed angiogenic factors as well as their interactions were studied the first time regarding a possible association with endometriosis.

STUDY DESIGN

This case-control study consisted of 205 biopsies of 114 patients comprising 61 endometriosis patients and 53 control patients. Among them in 29 cases paired samples were obtained. VEGFA, VEGFR2, HIF1A, HGF, NRP1, PDGFB, FGF18, TNFα, TGFB2, EPHB4, EPO and ANG mRNA expression was analyzed by qRT-PCR in ectopic tissue samples, in eutopic endometrium of women with and without endometriosis, and in unaffected peritoneum of women with and without endometriosis.

RESULTS

VEGFR2, HIF1A, HGF, PDGFB, NRP1 and EPHB4 are overexpressed in ectopic lesions compared to eutopic tissues. VEGFR2, HGF, PDGFB, NRP1, and EPHB4 showed highest mRNA levels in peritoneal implants, in contrast HIF1A showed the highest expression in ovarian endometriomas. Correlation analyses of angiogenic factors in ectopic lesions revealed the strongest associations between VEGFR2, PDGFB, and EPHB4. We further showed a significant upregulation of VEGFR2, HIF1A and EPHB4 in eutopic endometrium of women with endometriosis compared to that of controls and a trend towards upregulation of HGF. Additionally, a significant downregulation for HIF1A, HGF and EPHB4 was observed in unaffected peritoneal tissues of women with endometriosis compared to controls.

CONCLUSION

We identified new genes (EPHB4 and NRP1) that may contribute to angiogenesis in endometriosis beside known factors (VEGFA, VEGFR2, HIF1A, HGF, and PDGFB). Correlation studies revealed the putative importance of EBHB4 in association with endometriosis. Our analyses support preliminary reports that angiogenic factors seem to be differently expressed in peritoneal implants, ovarian endometriomas and deep infiltrating endometriosis. Our observation that angiogenic factors are differently expressed in the unaffected peritoneum of women with endometriosis compared to women without endometriosis underlines the importance of the peritoneum in the establishment of endometriosis.

SPOCK1 promotes tumor growth and metastasis in human prostate cancer

Prostate cancer is the most diagnosed noncutaneous cancer and ranks as the second leading cause of cancer-related deaths in American males. Metastasis is the primary cause of prostate cancer mortality. Survival rate is only 28% for metastatic patients, but is nearly 100% for patients with localized prostate cancers. Molecular mechanisms that underlie this malignancy remain obscure, and this study investigated the role of SPARC/osteonectin, cwcv, and kazal-like domain proteoglycan 1 (SPOCK1) in prostate cancer progression. Initially, we found that SPOCK1 expression was significantly higher in prostate cancer tissues relative to noncancerous tissues. In particular, SPOCK1 expression was also markedly high in metastatic tissues compared with nonmetastatic cancerous tissues. SPOCK1 expression knockdown by specific short hairpin RNA in PC3 cells was significantly inhibited, whereas SPOCK1 overexpression in RWPE-1 cells promoted cell viability, colony formation in vitro, and tumor growth in vivo. Moreover, the SPOCK1 knockdown in PC3 cells was associated with cell cycle arrest in G₀/G₁ phase, while the SPOCK1 overexpression in RWPE-1 cells induced cell cycle arrest in S phase. The SPOCK1 knockdown in PC3 cells even increased cell apoptosis. SPOCK1 modulation was also observed to affect cancerous cell proliferation and apoptotic processes in the mouse model of prostate cancer. Additionally, the SPOCK1 knockdown decreased, whereas the SPOCK1 overexpression increased cell migration and invasion abilities in vitro. Injection of SPOCK1-depleted PC3 cells significantly decreased metastatic nodules in mouse lungs. These findings suggest that SPOCK1 is a critical mediator of tumor growth and metastasis in prostate cancer.

Diagnostic and prognostic value of tissue and circulating levels of Ephrin-A2 in prostate cancer

Ephrin-A2, a member of the Eph/ephrin family, is associated with tumorigenesis and tumor progression. This study aimed to assess the diagnostic and prognostic value of both serum and tissue levels of Ephrin-A2 in prostate cancer (PCa) management. One hundred and forty-five frozen prostate tissues, 55 paraffin-embedded prostate tissues, 88 serum samples, and seven prostate cell lines (RWPE-1, LNCaP, LNCaP-LN3, PC-3, PC-3M, PC-3M-LN4, and DU145) were examined via quantitative reverse transcription-PCR (qRT-PCR), immunohistochemistry, enzyme-linked immunosorbent assay, and western blotting. Induced Ephrin-A2 messenger RNA (mRNA) or protein expression was detected in 8.6 % (5/58) benign prostatic hyperplasia (BPH), 59.8 % (52/87) PCa, and five prostate cancer cell lines. Ephrin-A2 immunostaining was present in 6.7 % (1/15) patients with BPHs and 62.5 % (25/40) clinically localized PCa. Accordingly, serum Ephrin-A2 was significantly higher in PCa patients compared to those in the BPH patients and controls (P < 0.001). The expression of Ephrin-A2 was higher in tumor patients with an elevated Gleason score or T3-T4 staging. Ephrin-A2 expression was correlated with Ki-67 expression in PCa patients, both at the gene scale and protein level. Our data indicate that Ephrin-A2 is a potential diagnostic and prognostic biomarker and a promising molecular therapeutic target to attenuate prostate cancer progression.