Anti-angiogenic and tumor-suppressive roles of candidate tumor-suppressor gene, Fibulin-2, in nasopharyngeal carcinoma

Hypermethylation of genes on chromosome 3p as a biomarker for nasopharyngeal carcinoma diagnosis: A Vietnamese case-control study

BACKGROUND

The crucial event driving nasopharyngeal tumorigenesis is the hypermethylation of chromosome 3p-located tumor suppressor genes. This case-control study aims to investigate the methylation characteristics of RASSF1A, Blu, ADAMTS9, and DLEC1 to potentially develop effective diagnostic biomarkers for nasopharyngeal carcinoma, either individually or in combination.

METHODS

The methylation of RASSF1A, Blu, ADAMTS9, and DLEC1 in the collection of 93 biopsy samples and 100 healthy swab specimens were evaluated by Nested methylation-specific polymerase chain reaction. The strength of the correlation between candidate genes and nasopharyngeal carcinoma was estimated by the evaluation of odds ratios (ORs).

RESULTS

Promoter hypermethylation of RASSF1A, Blu, ADAMTS9, and DLEC1 were found in 60.22%, 80.65%, 62.37%, and 74.19%, respectively, in nasopharyngeal carcinoma tumors. A significant association between the methylation status of candidate genes with nasopharyngeal carcinoma was reported. The methylation of candidate genes significantly increased the risk of nasopharyngeal carcinoma in cancerous samples compared with control samples (OR > 1). Based on the value of the methylation index, methylation of at least one gene was found in 95.70% of nasopharyngeal tumors. Additionally, the methylation index among 93 tumors significantly correlated with advanced stage nasopharyngeal tumors.

CONCLUSION

The study explored a higher frequency of hypermethylation at least one candidate gene. Methylation of a panel of potential genes can be utilized to discriminate between nasopharyngeal carcinoma and non-cancer cells, particularly in the advanced stages of nasopharyngeal carcinoma. Thus, it could serve as a valuable marker for the diagnosis and monitoring of nasopharyngeal carcinoma.

FBLN2 is associated with basal cell markers Krt14 and ITGB1 in mouse mammary epithelial cells and has a preferential expression in molecular subtypes of human breast cancer

BACKGROUND

Fibulin-2 (FBLN2) is a secreted extracellular matrix (ECM) glycoprotein and has been identified in the mouse mammary gland, in cap cells of terminal end buds (TEBs) during puberty, and around myoepithelial cells during early pregnancy. It is required for basement membrane (BM) integrity in mammary epithelium, and its loss has been associated with human breast cancer invasion. Herein, we attempted to confirm the relevance of FBLN2 to myoepithelial phenotype in mammary epithelium and to assess its expression in molecular subtypes of human breast cancer.

METHODS

The relationship between FBLN2 expression and epithelial markers was investigated in pubertal mouse mammary glands and the EpH4 mouse mammary epithelial cell line using immunohistochemistry, immunocytochemistry, and immunoblotting. Human breast cancer mRNA data from the METABRIC and TCGA datasets from Bioportal were analyzed to assess the association of Fbln2 expression with epithelial markers, and with molecular subtypes. Survival curves were generated using data from the METABRIC dataset and the KM databases.

RESULTS

FBLN2 knockdown in mouse mammary epithelial cells was associated with a reduction in KRT14 and an increase in KRT18. Further, TGFβ3 treatment resulted in the upregulation of FBLN2 in vitro. Meta-analyses of human breast cancer datasets from Bioportal showed a higher expression of Fbln2 mRNA in claudin-low, LumA, and normal-like breast cancers compared to LumB, Her2 +, and Basal-like subgroups. Fbln2 mRNA levels were positively associated with mesenchymal markers, myoepithelial markers, and markers of epithelial-mesenchymal transition. Higher expression of Fbln2 mRNA was associated with better prognosis in less advanced breast cancer and this pattern was reversed in more advanced lesions.

CONCLUSION

With further validation, these observations may offer a molecular prognostic tool for human breast cancer for more personalized therapeutic approaches.

Single-cell analyzing of tumor microenvironment and cell adhesion between early and late-stage lung cancer

Lung adenocarcinoma (LUAD) is a highly heterogeneous disease that threaten human life with serious incidence and high mortality. High heterogeneity of tumor microenvironment (TME) was reported in multiple studies. However, the factor of controlling the tumor migration progression between eary and late-stage LUAD is still not fully understood. In this study, we conducted a comprehensive analysis of single-cell RNA sequencing (scRNA-seq) data of LUAD obtained from the GEO database. The identification of cell clusters revealed significant expansion of epithelial cells in late-stage patients. Interpretation of the cell-cell communication results between early-stage and late-stage patient samples indicated that early tumor cells may interact with epithelial cells through the TGF-β pathway to promote tumor progression. The cell cycle analysis demonstrated a significant increase in the number of cells in the G2 and M phases in late-stage lung cancer. Further analysis using Non-negative Matrix Factorization (NMF) revealed early-stage cell-specific gene features involved in cell adhesion-related biological processes. Among these, the Tensin (TNS) gene family, particularly TNS1, showed high expression in epithelial cells and fibroblasts of early-stage samples, specifically associated with cell adhesion. Survival analysis using TCGA database for LUAD demonstrated that patients with high expression of TNS1 exhibited significantly higher overall survival rates compared to those with low expression. Immunofluorescence experiments have demonstrated co-expression of TNS1 with fibroblast and tumor cell markers (α-SMA and EPCAM). Immunohistochemistry experiments further validated the significantly higher expression levels of TNS1 in early-stage LUAD tissues compared to late-stage lung cancer tissues (P<0.05). Pathway experiments have shown that early-stage tumor patients with high expression of TNS1 exhibit stronger phosphorylation levels of Akt and mTOR, indicating a more potent activation of the Akt/mTOR signaling pathway. In conclusion, the results of this study demonstrate that TNS1 is an adhesive molecule in the immune microenvironment of early-stage tumor cells, and it may serve as a novel prognostic marker for lug cancer.

Angiogenesis in nasopharyngeal carcinoma: insights, imaging, and therapeutic strategies

Nasopharyngeal carcinoma (NPC) is a highly prevalent head and neck malignancy in southern China frequently diagnosed at advanced stages owing to subtle early symptoms and associated metastasis. Angiogenesis emerges as a pivotal factor in NPC progression, with numerous angiogenesis-related factors showing aberrant expression and contributing to increased neovascularization within NPC tumors. These abnormal vessels not only nourish tumor growth but also facilitate metastasis, culminating in unfavorable patient outcomes. Multiple studies have demonstrated the applicability of various imaging techniques for assessing angiogenesis in NPC tumors, thus serving as a foundation for personalized treatment strategies and prognostic assessments. Anti-angiogenic therapies have exhibited significant potential for inhibiting NPC angiogenesis and exerting anti-tumor effects. To enhance efficacy, anti-angiogenic drugs are frequently combined with other treatment modalities to synergistically enhance anti-tumor effects while mitigating the side effects associated with single-agent therapies, consequently improving patient prognosis. Identifying the potential mechanisms and key targets underlying NPC angiogenesis and exploring more effective detection and treatment approaches holds promise for shaping the future of NPC diagnosis, treatment, and prognosis, thereby offering new avenues and perspectives for research and clinical practice.

ITGBL1 promotes anoikis resistance and metastasis in human gastric cancer via the AKT/FBLN2 axis

The resistance to anoikis plays a critical role in the metastatic progression of various types of malignancies, including gastric cancer (GC). Nevertheless, the precise mechanism behind anoikis resistance is not fully understood. Here, our primary focus was to examine the function and underlying molecular mechanism of Integrin beta-like 1 (ITGBL1) in the modulation of anoikis resistance and metastasis in GC. The findings of our investigation have demonstrated that the overexpression of ITGBL1 significantly augmented the resistance of GC cells to anoikis and promoted their metastatic potential, while knockdown of ITGBL1 had a suppressive effect on both cellular processes in vitro and in vivo. Mechanistically, we proved that ITGBL1 has a role in enhancing the resistance of GC cells to anoikis and promoting metastasis through the AKT/Fibulin-2 (FBLN2) axis. The inhibition of AKT/FBLN2 signalling was able to reverse the impact of ITGBL1 on the resistance of GC cells to anoikis and their metastatic capability. Moreover, the expression levels of ITGBL1 were found to be significantly elevated in the cancerous tissues of patients diagnosed with GC, and there was a strong correlation observed between high expression levels of ITGBL1 and worse prognosis among individuals diagnosed with GC. Significantly, it was revealed that within our cohort of GC patients, individuals exhibiting elevated ITGBL1 expression and diminished FBLN2 expression experienced the worst prognosis. In conclusion, the findings of our study indicate that ITGBL1 may serve as a possible modulator of resistance to anoikis and the metastatic process in GC.

Genetics and Molecular Basis of Congenital Heart Defects in Down Syndrome: Role of Extracellular Matrix Regulation

Down syndrome (DS), a complex disorder that is caused by the trisomy of chromosome 21 (Hsa21), is a major cause of congenital heart defects (CHD). Interestingly, only about 50% of individuals with Hsa21 trisomy manifest CHD. Here we review the genetic basis of CHD in DS, focusing on genes that regulate extracellular matrix (ECM) organization. The overexpression of Hsa21 genes likely underlies the molecular mechanisms that contribute to CHD, even though the genes responsible for CHD could only be located in a critical region of Hsa21. A role in causing CHD has been attributed not only to protein-coding Hsa21 genes, but also to genes on other chromosomes, as well as miRNAs and lncRNAs. It is likely that the contribution of more than one gene is required, and that the overexpression of Hsa21 genes acts in combination with other genetic events, such as specific mutations or polymorphisms, amplifying their effect. Moreover, a key function in determining alterations in cardiac morphogenesis might be played by ECM. A large number of genes encoding ECM proteins are overexpressed in trisomic human fetal hearts, and many of them appear to be under the control of a Hsa21 gene, the RUNX1 transcription factor.

Regulation of epigenetic modifications in the head and neck tumour microenvironment

Head and neck tumours are common malignancies that are associated with high mortality. The low rate of early diagnosis and the high rates of local recurrence and distant metastasis are the main reasons for treatment failure. Recent studies have established that the tumour microenvironment (TME) can affect the proliferation and metastasis of head and neck tumours via several mechanisms, including altered expressions of certain genes and cytokines. Increasing evidence has shown that epigenetic modifications, such as DNA methylation, histone modification, RNA modification, and non-coding RNAs, can regulate the head and neck TME and thereby influence tumour development. Epigenetic modifications can regulate the expression of different genes and subsequently alter the TME to affect the progression of head and neck tumours. In addition, the cell components in the TME are regulated by epigenetic modifications, which, in turn, affect the behaviour of head and neck tumour cells. In this review, we have discussed the functions of epigenetic modifications in the head and neck TME. We have further examined the roles of such modifications in the malignancy and metastasis of head and neck tumours.

Annexin A2 promotes development of retinal neovascularization through PI3K/ AKT signaling pathway

PURPOSE

Retinal Neovascularization (RNV) is a pathological characteristic of ocular diseases. Annexin A2 (ANXA2) plays important roles in RNV while the mechanism remains unclear. The study aimed to explore relationship between ANXA2 and PI3K/AKT signaling pathway in RNV.

METHODS

We used human retinal vascular endothelial cells (HRECs) and oxygen-induced retinopathy (OIR) mice model to show ANXA2 can promote the development of RNV through PI3K/AKT signaling pathway. We divided HRECs into six groups by infecting lentivirus containing appropriate plasmid and adding corresponding solution. Assays showing ability of HRECs were performed in vitro. Mice were randomly divided into three groups and treated accordingly.

RESULTS

Expression of ANXA2 and activity of PI3K/AKT signaling pathway in HRECs were detected. RNV and expression of ANXA2 in mice retinas were detected. Results showed that ANXA2 expression is positively related with RNV-forming ability of HRECs in vitro and development of RNV in vivo while low activity of PI3K/AKT signaling pathway could attenuate the role of ANXA2.

CONCLUSIONS

We can make ANXA2 and PI3K/ AKT signaling pathway as a promising target for the regulation of pathological neovascularization of the retina, which also provides a novel idea for effective prevention and treatment of diseases related to RNV in future.

Fibulin 2 Is Hypermethylated and Suppresses Tumor Cell Proliferation through Inhibition of Cell Adhesion and Extracellular Matrix Genes in Non-Small Cell Lung Cancer

Fibulins (FBLNs), interacting with cell adhesion receptors and extracellular matrix (ECM) components, play multiple roles in ECM structures and tissue functions. Abnormal expression of FBLN2, one of the fibulin family members, contributes to tumor initiation and development. However, the function of FBLN2 in human non-small cell lung cancer (NSCLC) has not yet been elucidated. In this study, we found that FBLN2 was downregulated in 9 out of 11 lung cancer cell lines compared to normal bronchial epithelial cells, which was associated with DNA hypermethylation. Primary lung squamous cell carcinoma expressed significantly more FBLN2 protein compared to adenocarcinoma (p = 0.047). Ectopic expression of FBLN2 led to decreased cell proliferation, migration and invasion, accompanied by inactivated MAPK/ERK and AKT/mTOR pathways, while FBLN2 siRNA knockdown resulted in an opposite biological behaviour in NSCLC cells. Additionally, overexpression of FBLN2 led to dysregulation of cell adhesion molecules, ECM markers and a panel of lysate/exosome-derived-microRNAs, which are involved in cell adhesion and ECM remodelling. Taken together, our data indicate that FBLN2 is methylated and exerts a tumor suppressor function through modulation of MAPK/ERK and AKT pathways and regulation of cell adhesion and ECM genes. Moreover, FBLN2 might be a potential biomarker for the sub-classification of NSCLC.

Construction and Verification of a Hypoxia-Stemness-Based Gene Signature for Risk Stratification in Esophageal Cancer

Background

Numerous studies have shown that esophageal cancer (ESCA) contains areas of intertumoral hypoxia. It is widely accepted that the association of hypoxia with cancer stemness in the tumor microenvironment of ESCA is of profound clinical significance. However, reliable prognostic signatures based on hypoxia and cancer stemness are still lacking in ESCA.

Material/Methods

The t-SNE algorithm was used to estimate the hypoxia status based on the transcriptome profiles of the discovery cohort in the TCGA database. Median values of the stemness index were used to group and identify stemness-associated differentially expressed genes (DEGs). The LASSO method and Cox regression model were combined to screen for prognostic genes and to establish a genetic signature based on hypoxia-stemness. The robustness of the prognostic model was then tested in an external independent validation cohort of the GEO database.

Results

A total of 8 genes – FBLN2, IL17RB, CYP2W1, AMTN, FABP1, FOXA2, GAS1, and CTSF – were identified to construct a gene signature for ESCA risk stratification. Overall survival was significantly lower in the high-risk group than in the low-risk group in both the internal discovery set and the external validation set. The risk score was found to be an independent prognostic factor for ESCA patients. In addition, a higher risk score was significantly associated with the sensitivity of ESCA patients to gefitinib, bexarotene, dasatinib, and imatinib.

Conclusions

The hypoxia-stemness-based genetic signature established for the first time in our study could be a promising tool for ESCA cancer risk stratification.

Inactivation of EMILIN-1 by Proteolysis and Secretion in Small Extracellular Vesicles Favors Melanoma Progression and Metastasis

Several studies have demonstrated that melanoma-derived extracellular vesicles (EVs) are involved in lymph node metastasis; however, the molecular mechanisms involved are not completely defined. Here, we found that EMILIN-1 is proteolyzed and secreted in small EVs (sEVs) as a novel mechanism to reduce its intracellular levels favoring metastasis in mouse melanoma lymph node metastatic cells. Interestingly, we observed that EMILIN-1 has intrinsic tumor and metastasis suppressive-like properties reducing effective migration, cell viability, primary tumor growth, and metastasis. Overall, our analysis suggests that the inactivation of EMILIN-1 by proteolysis and secretion in sEVs reduce its intrinsic tumor suppressive activities in melanoma favoring tumor progression and metastasis.

Role of Fibulins in Embryonic Stage Development and Their Involvement in Various Diseases

The extracellular matrix (ECM) plays an important role in the evolution of early metazoans, as it provides structural and biochemical support to the surrounding cells through the cell–cell and cell–matrix interactions. In multi-cellular organisms, ECM plays a pivotal role in the differentiation of tissues and in the development of organs. Fibulins are ECM glycoproteins, found in a variety of tissues associated with basement membranes, elastic fibers, proteoglycan aggregates, and fibronectin microfibrils. The expression profile of fibulins reveals their role in various developmental processes such as elastogenesis, development of organs during the embryonic stage, tissue remodeling, maintenance of the structural integrity of basement membrane, and elastic fibers, as well as other cellular processes. Apart from this, fibulins are also involved in the progression of human diseases such as cancer, cardiac diseases, congenital disorders, and chronic fibrotic disorders. Different isoforms of fibulins show a dual role of tumor-suppressive and tumor-promoting activities, depending on the cell type and cellular microenvironment in the body. Knockout animal models have provided deep insight into their role in development and diseases. The present review covers details of the structural and expression patterns, along with the role of fibulins in embryonic development and disease progression, with more emphasis on their involvement in the modulation of cancer diseases.

Fibulin-2: A Novel Biomarker for Differentiating Grade II from Grade I Meningiomas

There is an unmet need for the identification of biomarkers to aid in the diagnosis, clinical management, prognosis and follow-up of meningiomas. There is currently no consensus on the optimum management of WHO grade II meningiomas. In this study, we identified the calcium binding extracellular matrix glycoprotein, Fibulin-2, via mass-spectrometry-based proteomics, assessed its expression in grade I and II meningiomas and explored its potential as a grade II biomarker. A total of 87 grade I and 91 grade II different meningioma cells, tissue and plasma samples were used for the various experimental techniques employed to assess Fibulin-2 expression. The tumours were reviewed and classified according to the 2016 edition of the Classification of the Tumours of the central nervous system (CNS). Mass spectrometry proteomic analysis identified Fibulin-2 as a differentially expressed protein between grade I and II meningioma cell cultures. Fibulin-2 levels were further evaluated in meningioma cells using Western blotting and Real-time Quantitative Polymerase Chain Reaction (RT-qPCR); in meningioma tissues via immunohistochemistry and RT-qPCR; and in plasma via Enzyme-Linked Immunosorbent Assay (ELISA). Proteomic analyses (p < 0.05), Western blotting (p < 0.05) and RT-qPCR (p < 0.01) confirmed significantly higher Fibulin-2 (FBLN2) expression levels in grade II meningiomas compared to grade I. Fibulin-2 blood plasma levels were also significantly higher in grade II meningioma patients compared to grade I patients. This study suggests that elevated Fibulin-2 might be a novel grade II meningioma biomarker, when differentiating them from the grade I tumours. The trend of Fibulin-2 expression observed in plasma may serve as a useful non-invasive biomarker.

Prognostic Utility of FBLN2 Expression in Patients With Urothelial Carcinoma

Background: Abnormal extracellular matrix (ECM) remodeling plays an essential role in urothelial carcinoma (UC) invasiveness and metastasis. Focusing on the ECM structural constituent (GO: 0005201), we recognized a significant upregulation of the fibulin 2 gene (FBLN2) during UC progression in a published UC transcriptome (GSE31684). Thus, we aimed to investigate the roles of FBLN2 expression and its prognostic value in upper urinary tract UC (UTUC) and urinary bladder UC (UBUC) in our large, well-characterized cohort. Patients and Methods: Clinicopathological data and formalin-fixed paraffin-embedded UC tissues were analyzed retrospectively. We determined FBLN2 expression using immunohistochemical staining assessed by H-scores. FBLN2 expression correlated with clinicopathological features and patient outcomes, including metastasis-free survival (MFS) and disease-specific survival (DSS). Statistical analyses were performed using Pearson's chi-square test, Kaplan-Meier estimates of DSS and MFS, and the Cox proportional hazards model. We used Ingenuity Pathway Analysis (IPA) to clarify the functional significance of dysregulated FBLN2 in UC. Results: Data from 295 UBUC and 340 UTUC patients were available for the final evaluation. Pearson's chi-square test showed that high FBLN2 immunoexpression significantly correlated with adverse pathologic variables, such as advanced pathologic tumor stage, high histological grade, perineural invasion, vascular invasion, lymph node metastasis, and increased mitotic rate (all p < 0.05). Kaplan-Meier analysis demonstrated associations of high FBLN2 expression with worse DSS (p < 0.001) and MFS (p < 0.001). Furthermore, multivariate analysis identified high FBLN2 expression as an independent predictive risk factor for DSS [hazard ratio (HR) in UBUC, 2.306, p = 0.014; in UTUC, 2.561, p = 0.012] and MFS (HR in UBUC, 2.493, p = 0.001; in UTUC, 2.837, p = 0.001). IPA demonstrated that multiple signaling pathways were enriched, including the oxidative phosphorylation, mitochondrial dysfunction, and regulation of the epithelial-mesenchymal transition pathways. Conclusion: High FBLN2 expression was associated with adverse pathologic features and worse oncological outcomes and may serve as a prognostic biomarker for UC.

Atherosclerotic Pre-Conditioning Affects the Paracrine Role of Circulating Angiogenic Cells Ex-Vivo

In atherosclerosis, circulating angiogenic cells (CAC), also known as early endothelial progenitor cells (eEPC), are thought to participate mainly in a paracrine fashion by promoting the recruitment of other cell populations such as late EPC, or endothelial colony-forming cells (ECFC), to the injured areas. There, ECFC replace the damaged endothelium, promoting neovascularization. However, despite their regenerative role, the number and function of EPC are severely affected under pathological conditions, being essential to further understand how these cells react to such environments in order to implement their use in regenerative cell therapies. Herein, we evaluated the effect of direct incubation ex vivo of healthy CAC with the secretome of atherosclerotic arteries. By using a quantitative proteomics approach, 194 altered proteins were identified in the secretome of pre-conditioned CAC, many of them related to inhibition of angiogenesis (e.g., endostatin, thrombospondin-1, fibulins) and cell migration. Functional assays corroborated that healthy CAC released factors enhanced ECFC angiogenesis, but, after atherosclerotic pre-conditioning, the secretome of pre-stimulated CAC negatively affected ECFC migration, as well as their ability to form tubules on a basement membrane matrix assay. Overall, we have shown here, for the first time, the effect of atherosclerotic factors over the paracrine role of CAC ex vivo. The increased release of angiogenic inhibitors by CAC in response to atherosclerotic factors induced an angiogenic switch, by blocking ECFC ability to form tubules in response to pre-conditioned CAC. Thus, we confirmed here that the angiogenic role of CAC is highly affected by the atherosclerotic environment.

Roles of Fibulin-2 in Carcinogenesis

Fibulin-2, an extracellular matrix (ECM) protein expressed in normal epithelia, is a kind of fibulin which is associated with basement membranes (BM) and elastic ECM fibers. The role of fibulin-2 has been recognized as an oncogene. The upregulation of fibulin-2 correlates with cancer development and progression. Furthermore, the upregulation of fibulin has been detected in ovarian cancer and stomach adenocarcinoma. However, the downregulation of fibulin has been detected in different intestinal and respiratory tumor cells. Additional studies have revealed that the role of fibulin-2 in carcinogenesis is context dependent and is caused by the interaction of fibulin proteins such as cell surface receptors and other ECM proteins, including integrins and syndecans. The present study summarizes the role of fibulin in carcinogenesis and its underlying molecular mechanism.

Identification of Potential Therapeutic Gene Markers in Nasopharyngeal Carcinoma Based on Bioinformatics Analysis

Nasopharyngeal carcinoma (NPC) is a common cancer found in the nasopharynx with high metastatic and invasive nature. Increasing evidences have identified the critical role of gene therapy in NPC treatment. Hence, this study was designed to identify specific gene markers that affected NPC progression through gene expression profile analysis. NPC‐related gene expression data set gene set enrichment (GSE)53819 were retrieved and analyzed to screen out differentially expressed genes (DEGs), followed by determination of their expression in noncancerous tissues and NPC specimens. Next, weighted gene co‐expression network analysis (WGCNA) was conducted on DEGs to obtain tumor‐associated gene modules. Genes in those modules were intersected with DEGs for gene ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis. Then protein‐protein interaction network of tumor‐associated genes was constructed to select genes most closely linked to NPC. Afterward, expression of chromosome 9 open reading frame 24 (c9orf24), primary ciliary dyskinesia protein 1 (PCDP1), and leucine‐rich repeat‐containing protein 46 (LRRC46) was detected in GSE53819 and further verified in GSE12452 and GSE64634. Differential analysis on GSE53819 found that 2,173 genes were aberrantly expressed in NPC, among which 917 genes are upregulated and 1,256 genes are downregulated. WGCNA showed that genes were enriched in 17 modules and 727 genes exhibited ectopic expression in NPC and enriched in cytokine‐cytokine receptor interaction, cytochrome P450, and chemical carcinogenesis signaling pathways, among which c9orf24, PCDP1, and LRRC46 were poorly expressed in NPC. Therefore, c9orf24, PCDP1, and LRRC46 might serve as prominent diagnostic markers for NPC, which presents new insights for NPC therapy.

EFEMP2 Inhibits Breast Cancer Invasion And Metastasis In Vitro And In Vivo

Background

EGF-containing fibulin-like extracellular matrix protein 2 (EFEMP2) is an extracellular matrix (ECM) glycoprotein, which is regarded as potential prognostic biomarkers in some carcinoma. Little is known about the association of EFEMP2 and breast cancer.

Methods

EFEMP2 expressions in normal breast tissue, benign fibroadenoma, breast cancer, the normal mammary epithelial cell line, and 4 different invasive breast cancer cell lines were evaluated by immunohistochemistry (IHC) or immunocytochemistry (ICC) and real time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR). Expression and prognostic value of EFEMP2 in breast cancer were verified by the Public databases (Oncomine and Kaplan-Meier plotter database). Lentiviral vector with EFEMP2 cDNA was constructed and used to infect breast cancer cell lines to investigate the effects of EFEMP2 on the biological behavior of breast cancer cells by functional in vitro and in vivo assays.

Results

Down-regulated EFEMP2 expression was found in breast cancer tissues and cells, and low expression of EFEMP2 was associated with poor prognosis in patients with breast cancer. Analysis by the Public database leaded to the same conclusion. Up-regulated EFEMP2 expression significantly hampered the invasion and metastasis abilities of breast cancer cells and the process of epithelial interstitial transformation (EMT) via the Wnt/β-catenin pathway.

Conclusion

EFEMP2 expression was lower in breast cancer and closely related to the prognosis of patients, its anti-oncogenic roles indicated the underlying therapeutic target for the future treatment of breast cancer.

Cellular Recruitment by Podocyte-Derived Pro-migratory Factors in Assembly of the Human Renal Filter

Analysis of kidney disease-causing genes and pathology resulting from systemic diseases highlight the importance of the kidney's filtering system, the renal corpuscles. To elucidate the developmental processes that establish the renal corpuscle, we performed single-nucleus droplet-based sequencing of the human fetal kidney. This enabled the identification of nephron, interstitial, and vascular cell types that together generate the renal corpuscles. Trajectory analysis identified transient developmental gene expression, predicting precursors or mature podocytes express FBLN2, BMP4, or NTN4, in conjunction with recruitment, differentiation, and modeling of vascular and mesangial cell types into a functional filter. In vitro studies provide evidence that these factors exhibit angiogenic or mesangial recruiting and inductive properties consistent with a key organizing role for podocyte precursors in kidney development. Together these studies define a spatiotemporal developmental program for the primary filtration unit of the human kidney and provide novel insights into cell interactions regulating co-assembly of constituent cell types.

Identification of a Novel Candidate Gene for Serrated Polyposis Syndrome Germline Predisposition by Performing Linkage Analysis Combined With Whole-Exome Sequencing

OBJECTIVES

Serrated polyposis syndrome (SPS) is a complex disorder with a high risk of colorectal cancer for which the germline factors remain largely unknown. Here, we combined whole-exome sequencing (WES) and linkage studies in families with multiple members affected by SPS to identify candidate genes harboring rare variants with higher penetrance effects.

METHODS

Thirty-nine affected subjects from 16 extended SPS families underwent WES. Genome-wide linkage analysis was performed under linear and exponential models. The contribution of rare coding variants selected to be highly pathogenic was assessed using the gene-based segregation test.

RESULTS

A significant linkage peak was identified on chromosome 3p25.2-p22.3 (maxSNP = rs2293787; LODlinear = 2.311, LODexp = 2.11), which logarithm of the odds (LOD) score increased after fine mapping for the same marker (maxSNP = rs2293787; LODlinear = 2.4, LODexp = 2.25). This linkage signal was replicated in 10 independent sets of random markers from this locus. To assess the contribution of rare variants predicted to be pathogenic, we performed a family-based segregation test with 11 rare variants predicted to be deleterious from 10 genes under the linkage intervals. This analysis showed significant segregation of rare variants with SPS in CAPT7, TMEM43, NGLY1, and FBLN2 genes (weighted P value > 0.007).

DISCUSSION

Protein network analysis suggested FBLN2 as the most plausible candidate genes for germline SPS predisposition. Etiologic rare variants implicated in disease predisposition may be identified by combining traditional linkage with WES data. This powerful approach was effective for the identification of a new candidate gene for hereditary SPS.

Abrogation of EMILIN1-β1 integrin interaction promotes experimental colitis and colon carcinogenesis

Colon cancer is one of the first tumor types where a functional link between inflammation and tumor onset has been described; however, the microenvironmental cues affecting colon cancer progression are poorly understood. Here we demonstrate that the expression of the ECM molecule EMILIN-1 halts the development of AOM-DSS induced tumors. In fact, upon AOM-DSS treatment the Emilin1^-/- (E1^-/-) mice were characterized by a higher tumor incidence, bigger adenomas and less survival. Similar results were obtained with the E933A EMILIN-1 (E1-E933A) transgenic mouse model, expressing a mutant EMILIN-1 unable to interact with α4/α9β1 integrins. Interestingly, upon chronic treatment with DSS, E1^-/- and E1-E933A mice were characterized by the presence of increased inflammatory infiltrates, higher colitis scores and more severe mucosal injury respect to the wild type (E1^+/+) mice. Since alterations of the intestinal lymphatic network are a well-established feature of human inflammatory bowel disease and EMILIN-1 is a key structural element in the maintenance of the integrity of lymphatic vessels, we assessed the lymphatic vasculature in this context. The analyses revealed that both E1^-/- and E1-E933A mice displayed a higher density of LYVE-1 positive vessels; however, their functionality was severely compromised after colitis induction. Taken together, these results suggest that the loss of EMILIN-1 expression may cause the reduction of the inflammatory resolution during colon cancer progression due to a decreased lymph flow and impaired inflammatory cell drainage.

Novel Associations Within the Tumor Microenvironment: Fibulins Meet ADAMTSs

The maintenance of tissue homeostasis in any organism is a very complex and delicate process in which numerous factors intervene. Cellular homeostasis not only depends on intrinsic factors but also relies on external factors that compose the microenvironment or cellular niche. Thus, extracellular matrix (ECM) components play a very important role in maintaining cell survival and behavior, and alterations in the ECM composition can lead to different pathologies. Fibulins and ADAMTS metalloproteases play crucial roles in the upkeep and function of the ECM in different tissues. In fact, members of both of these families of secreted multidomain proteins can interact with numerous other ECM components and thus shape or regulate the molecular environment. Individual members of both families have been implicated in tumor-related processes by exhibiting either pro- or antitumor properties. Recent studies have shown both an important relation among members of both families and their participation in several pathologies, including cardiogenesis or cancer. In this review, we summarize the associations among fibulins and ADAMTSs and the effects elicited by those interactions on cellular behavior.

Oncoproteomic and gene expression analyses identify prognostic biomarkers for second primary malignancy in patients with head and neck squamous cell carcinoma

Patients with head and neck squamous cell carcinoma are at increased risk of developing a second primary malignancy, which is associated with poor prognosis and early death. To help improve clinical outcome, we aimed to identify biomarkers for second primary malignancy risk prediction using the routinely obtained formalin-fixed paraffin-embedded tissues of the index head and neck cancer. Liquid chromatography-tandem mass spectrometry was initially performed for candidate biomarker discovery in 16 pairs of primary cancer tissues and their matched normal mucosal epithelia from head and neck squamous cell carcinoma patients with or without second primary malignancy. The 32 candidate proteins differentially expressed between head and neck cancers with and without second primary malignancy were identified. Among these, 30 selected candidates and seven more from literature review were further studied using NanoString nCounter gene expression assay in an independent cohort of 49 head and neck cancer patients. Focusing on the p16-negative cases, we showed that a multivariate logistic regression model comprising the expression levels of ITPR3, KMT2D, EMILIN1, and the patient's age can accurately predict second primary malignancy occurrence with 88% sensitivity and 75% specificity. Furthermore, using Cox proportional hazards regression analysis and survival analysis, high expression levels of ITPR3 and DSG3 were found to be significantly associated with shorter time to second primary malignancy development (log-rank test P = 0.017). In summary, we identified a set of genes whose expressions may serve as the prognostic biomarkers for second primary malignancy occurrence in head and neck squamous cell carcinomas. In combination with the histopathologic examination of index tumor, these biomarkers can be used to guide the optimum frequency of second primary malignancy surveillance, which may lead to early diagnosis and better survival outcome.

The expression level of fibulin-2 in the circulating RNA (ctRNA) of epithelial tumor cells of peripheral blood and tumor tissue of patients with metastatic lung cancer

The Fibulins are a recently discovered family of extracellular matrix proteins. In this study, expression levels of the fibulin-2 (FBLN2) gene and its role in the formation of different metastatic foci were investigated in lung cancer patients. We analyzed 106 lung cancer patients and eight paraffin-embedded tissues, and 27 ethnical-, age- and sex-matched healthy controls for expression levels of the FBLN2 gene. cDNAs obtained from the enriched epithelial cells of peripheral blood lymphocytes and tumor tissues of patients were amplified with specific primers for the target FBLN2 gene and HPRT1 housekeeping gene using quantitative real-time polymerase chain reaction. FBLN2 gene expression levels of the enriched epithelial cells of peripheral blood lymphocytes were found to be decreased approximately twofold in all subsets of patients compared to healthy controls. Our results indicate a significant difference between patient subgroups and controls [F(4.124) = 14.846, p0.05] among patient subgroups: bone metastases versus non-metastatic groups (p = 0.997), bone versus brain metastases (p = 0994), bone metastases versus two primary tumors (p = 0.999), brain metastases versus two primary tumors (p = 0.999), brain metastases versus non-metastatic (p = 0.755), non-metastatic versus two primary tumors (p = 0.996), non-metastatic versus all other metastatic patients (p = 0.731). Moreover, we found a 50-fold upregulation of FBLN2 gene expression in paraffin-embedded tissues compared with the enriched epithelial cells of peripheral blood lymphocytes of patients. In the study, the enriched epithelial cells of peripheral blood lymphocytes of decreased FBLN2 expression was found to be correlated with metastasis. The fibulin-2 molecules might induce the metastatic potential through interaction with the other molecules in the microenvironment, nevertheless, it is needed further research whether the importance of FBLN2 on lung cancer oncogenesis and as a biomarker for metastatic lung cancer.

Defining UHRF1 Domains that Support Maintenance of Human Colon Cancer DNA Methylation and Oncogenic Properties

UHRF1 facilitates the establishment and maintenance of DNA methylation patterns in mammalian cells. The establishment domains are defined, including E3 ligase function, but the maintenance domains are poorly characterized. Here, we demonstrate that UHRF1 histone- and hemimethylated DNA binding functions, but not E3 ligase activity, maintain cancer-specific DNA methylation in human colorectal cancer (CRC) cells. Disrupting either chromatin reader activity reverses DNA hypermethylation, reactivates epigenetically silenced tumor suppressor genes (TSGs), and reduces CRC oncogenic properties. Moreover, an inverse correlation between high UHRF1 and low TSG expression tracks with CRC progression and reduced patient survival. Defining critical UHRF1 domain functions and its relationship with CRC prognosis suggests directions for, and value of, targeting this protein to develop therapeutic DNA demethylating agents.

Detection and Analysis of RNAs Expression Profile for Methylated Candidate Tumor Suppressor Genes in Nasopharyngeal Carcinoma

BACKGROUND

DNA methylation, which acts as an expression regulator for multiple Tumor Suppressor Genes (TSGs), is believed to play an important role in Nasopharyngeal Carcinoma (NPC) development.

METHODS

We compared the effects of 5-aza-2-deoxycytidine (decitabine, DAC) on gene expression using RNA sequencing in NPC cells.

RESULTS

We analyzed Differentially Expressed Genes (DEGs) in NPC cells using DAC demethylation treatment and found that 2182 genes were significantly upregulated (≥ 2-fold change), suggesting that they may play a key role in cell growth, proliferation, development, and death. For data analysis, we used the Gene Ontology database and pathway enrichment analysis of the DEGs to discover differential patterns of DNA methylation associated with changes in gene expression. Furthermore, we evaluated 74 methylated candidate TSGs from the DEGs in NPC cells and summarized these genes in several important signaling pathways frequently disrupted by promoter methylation in NPC tumorigenesis.

CONCLUSION

Our study analyzes the DEGs and identifies a set of genes whose promoter methylation in NPC cells is reversed by DAC. These genes are potential substrates of DNMT inhibitors and may serve as tumor suppressors in NPC cells.

A novel prognostic signature of seven genes for the prediction in patients with thymoma

Purpose

A thymoma is a tumor arising from the epithelium of the thymus, mostly occurring in the anterior mediastinum. The incidence of this disease is low and research progress in this field is slow. Consequently, there is an urgent need to investigate the correlation between molecular regulation and the prediction of survival and prognosis in patients with thymoma.

Methods

We collected thymoma datasets from The Cancer Genome Atlas (TCGA). Differentially expressed genes (DEGs) of TCGA datasets were then determined using R software. A gene signature was obtained by screening prognostic DEGs from the TCGA datasets using univariate and multivariate Cox survival analysis. The summation of the weighted expression levels was calculated as a risk score, which could then be used to predict the survival rate and prognosis of patients with thymoma. The validity of this model was verified by the analysis of receiver operating characteristic (ROC) curves and area under the curve (AUC).

Results

In total, 297 DEGs were identified from the integrated results of TCGA datasets. A seven-gene signature, along with a regression model of prognostic risk, was obtained by Cox survival analysis. The expression levels of the seven genes were then weighted and summed to calculate the risk score for each sample. Patients were effectively divided into high- and low-risk groups using the median risk score (P < 0.05). ROC analysis showed that this Cox regression model was effective in predicting the prognosis of patients with thymus tumors (AUC = 0.983, P < 0.05).

Conclusion

For the first time, we identified an effective seven-gene signature in patients with thymic tumors. In the future, the risk and prognosis of patients can be preliminarily assessed using this model, although further testing is required to improve rigor.

Fibulin-2 is required for basement membrane integrity of mammary epithelium

Fibulin-2 (FBLN2) is a secreted extracellular matrix glycoprotein which has been associated with tissue development and remodelling. In the mouse mammary gland, FBLN2 can be detected during ductal morphogenesis in cap cells and myoepithelial cells at puberty and early pregnancy, respectively. In an attempt to assign its function, we knocked down Fbln2 in the mouse mammary epithelial cell line EpH4. FBLN2 reduction led to an increase in the size of spheroidal structures when compared to scrambled control shRNA-transduced cells plated on Matrigel matrix. This phenotype was associated with a disruption of the collagen IV sheath around the epithelial spheroids and downregulation of integrin β1, suggesting a role for FBLN2 in stabilizing the basement membrane (BM). In contrast to mice, in normal adult human breast tissue, FBLN2 was detected in ductal stroma, and in the interlobular stroma, but was not detectable within the lobular regions. In tissue sections of 65 breast cancers FBLN2 staining was lost around malignant cells with retained staining in the neighbouring histologically normal tissue margins. These results are consistent with a role of FBLN2 in mammary epithelial BM stability, and that its down-regulation in breast cancer is associated with loss of the BM and early invasion.

Extracellular Interactions between Fibulins and Transforming Growth Factor (TGF)-β in Physiological and Pathological Conditions

Transforming growth factor (TGF)-β is a multifunctional peptide growth factor that has a vital role in the regulation of cell growth, differentiation, inflammation, and repair in a variety of tissues, and its dysregulation mediates a number of pathological conditions including fibrotic disorders, chronic inflammation, cardiovascular diseases, and cancer progression. Regulation of TGF-β signaling is multifold, but one critical site of regulation is via interaction with certain extracellular matrix (ECM) microenvironments, as TGF-β is primarily secreted as a biologically inactive form sequestrated into ECM. Several ECM proteins are known to modulate TGF-β signaling via cell–matrix interactions, including thrombospondins, SPARC (Secreted Protein Acidic and Rich in Cystein), tenascins, osteopontin, periostin, and fibulins. Fibulin family members consist of eight ECM glycoproteins characterized by a tandem array of calcium-binding epidermal growth factor-like modules and a common C-terminal domain. Fibulins not only participate in structural integrity of basement membrane and elastic fibers, but also serve as mediators for cellular processes and tissue remodeling as they are highly upregulated during embryonic development and certain disease processes, especially at the sites of epithelial–mesenchymal transition (EMT). Emerging studies have indicated a close relationship between fibulins and TGF-β signaling, but each fibulin plays a different role in a context-dependent manner. In this review, regulatory interactions between fibulins and TGF-β signaling are discussed. Understanding biological roles of fibulins in TGF-β regulation may introduce new insights into the pathogenesis of some human diseases.

Identification of the extracellular matrix protein Fibulin-2 as a regulator of spinal nerve organization

During amniote peripheral nervous system development, segmentation ensures the correct patterning of the spinal nerves relative to the vertebral column. Along the antero-posterior (rostro-caudal) axis, each somite-derived posterior half-sclerotome expresses repellent molecules to restrict axon growth and neural crest migration to the permissive anterior half-segment. To identify novel regulators of spinal nerve patterning, we investigated the differential gene expression of anterior and posterior half-sclerotomes in the chick embryo by RNA-sequencing. Several genes encoding extracellular matrix proteins were found to be enriched in either anterior (e.g. Tenascin-C, Laminin alpha 4) or posterior (e.g. Fibulin-2, Fibromodulin, Collagen VI alpha 2) half-sclerotomes. Among them, the extracellular matrix protein Fibulin-2 was found specifically restricted to the posterior half-sclerotome. By using in ovo ectopic expression in chick somites, we found that Fibulin-2 modulates spinal axon growth trajectories in vivo. While no intrinsic axon repellent activity of Fibulin-2 was found, we showed that it enhances the growth cone repulsive activity of Semaphorin 3A in vitro. Some molecules regulating axon growth during development are found to be upregulated in the adult central nervous system (CNS) following traumatic injury. Here, we found increased Fibulin-2 protein levels in reactive astrocytes at the lesion site of a mouse model of CNS injury. Together, these results suggest that the developing vertebral column and the adult CNS share molecular features that control axon growth and plasticity, which may open up the possibility for the identification of novel therapeutic targets for brain and spinal cord injury.

Blockage of store-operated Ca2+ entry antagonizes Epstein-Barr virus-promoted angiogenesis by inhibiting Ca2+ signaling-regulated VEGF production in nasopharyngeal carcinoma

Background

Epstein-Barr virus (EBV) actively contributes to the pathological process of nasopharyngeal carcinoma (NPC) by enabling NPC cells to acquire various capacities required for their malignant biological actions. Our earlier works demonstrated that EBV-encoded latent membrane protein 1 (LMP1) enhanced vascular endothelial growth factor (VEGF)-mediated angiogenesis by boosting store-operated Ca²⁺ entry (SOCE) upon extracellular epidermal growth factor (EGF) stimulation. However, the antagonistic effects of SOCE blockage on EBV-promoted angiogenesis must be appropriately evaluated in vivo, and the global effect of EBV infection on the EGF-elicited cytosolic Ca²⁺ signaling, which regulates VEGF-mediated angiogenesis remains to be further clarified.

Materials and methods

Two EBV-infected NPC cell lines, CNE2-EBV and HK1-EBV, along with their parental cell lines were employed in the present study. Dynamic cytosolic Ca²⁺ changes were measured in individual fluorescent Ca²⁺ indicator-loaded cells. Amounts of VEGF production were determined by enzyme-linked immunosorbent assay (ELISA). Human umbilical vein endothelial cells (HUVECs)-formed tube networks were quantitatively evaluated as an in vitro angiogenesis assay. A mouse model concurrently bearing EBV-positive/negative xenografts was utilized to evaluate the tumor growth and angiogenesis in vivo.

Results

EBV infection reliably promoted transplanted tumor growth while enhancing angiogenesis. Introduction of EBV into EBV-negative NPC cells increased the EGF-stimulated VEGF production while amplifying the EGF-evoked Ca²⁺ responses. Inhibition of the EBV-boosted Ca²⁺ signaling using 2-aminoethyl diphenylborinate (2-APB), a specific SOCE inhibitor, effectively antagonized the EBV-promoted VEGF production and endothelial tube formation in vitro. Pharmacological blockage of SOCE exhibited anti-angiogenic effect in the EBV-positive xenografts.

Conclusion

SOCE can serve as a candidate pharmacological target for treating NPC, as blockage of the Ca²⁺ signaling via SOCE is a feasible strategy to suppress the EBV-driven malignant profiles in NPC cells.

Metastasis-suppressing NID2, an epigenetically-silenced gene, in the pathogenesis of nasopharyngeal carcinoma and esophageal squamous cell carcinoma

Nidogen-2 (NID2) is a key component of the basement membrane that stabilizes the extracellular matrix (ECM) network. The aim of the study is to analyze the functional roles of NID2 in the pathogenesis of nasopharyngeal carcinoma (NPC) and esophageal squamous cell carcinoma (ESCC). We performed genome-wide methylation profiling of NPC and ESCC and validated our findings using the methylation-sensitive high-resolution melting (MS-HRM) assay. Results showed that promoter methylation of NID2 was significantly higher in NPC and ESCC samples than in their adjacent non-cancer counterparts. Consistently, down-regulation of NID2 was observed in the clinical samples and cell lines of both NPC and ESCC. Re-expression of NID2 suppresses clonogenic survival and migration abilities of transduced NPC and ESCC cells. We showed that NID2 significantly inhibits liver metastasis. Mechanistic studies of signaling pathways also confirm that NID2 suppresses the EGFR/Akt and integrin/FAK/PLCγ metastasis-related pathways. This study provides novel insights into the crucial tumor metastasis suppression roles of NID2 in cancers.

Apolipoprotein A-I Is a Prognosticator of Nasopharyngeal Carcinoma in the Era of Intensity-modulated Radiotherapy

Background: In the era of intensity-modulated radiotherapy (IMRT), distant metastasis remains the major cause of death from nasopharyngeal carcinoma (NPC). This study aimed to evaluate the clinical value of pretreatment serum lipid profiles in predicting clinical outcome of NPC.

Methodology / Principal Findings: A total of 1927 consecutive patients who had untreated NPC and completed radical IMRT between Jan. 2010 and Dec. 2011 were retrospectively reviewed. Pretreatment serum lipid indexes including total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein A-I (apoAI) and apolipoprotein B were analyzed for their association with survivals, together with the clinical features (age, sex, pathological type, anemia, chemotherapy sequence and Epstein-Barr virus deoxyribonucleic acid). Hazard ratio (HR) and 95% confidence interval (CI) were calculated for each independent prognosticator. After univariate and multivariate survival analysis, low apoAI level (< 1.125 mmol/L) appeared to predict poor 5-year overall survival (OS), disease-free survival (DFS) and distant-metastasis-free survival (DMFS).The HRs were 1.549 (95% CI, 1.137-2.109), 1.293 (95% CI, 1.047-1.597) and 1.288 (95% CI, 1.022-1.623), respectively. Subgroup survival analysis showed that the apoAI maintained predicting independence for OS, DFS and DMFS in patients with locally advanced NPC, even in those treated with concurrent chemoradiotherapy.

Conclusions / Significance: NPC patient with low serum level of pretreatment apoAI might be at risk of distant metastasis. Treatment aiming to eradicate distant metastasis might improve survival of these patients.

Cleavage of Fibulin-2 by the aggrecanases ADAMTS-4 and ADAMTS-5 contributes to the tumorigenic potential of breast cancer cells

Fibulin-2 participates in the assembly of extracellular matrix components through interactions with multiple ligands and promotes contacts between cells and their surrounding environment. Consequently, identification of processes that could lead to an altered Fibulin-2 could have a major impact not only in the maintenance of tissue architecture and morphogenesis but also in pathological situations including cancer. Herein, we have investigated the ability of the secreted metalloproteases ADAMTS-4 and ADAMTS-5 to digest Fibulin-2. Using in vitro approaches and cultured breast cancer cell lines we demonstrate that Fibulin-2 is a better substrate for ADAMTS-5 than it is for ADAMTS-4. Moreover, Fibulin-2 degradation is associated to an enhancement of the invasive potential of T47D, MCF-7 and SK-BR-3 cells. We have also found that conditioned medium from MCF-7 cells that simultaneously overexpress Fibulin-2 and ADAMTS-5 significantly induced the migratory and invasive ability of normal breast fibroblasts using 3D collagen matrices. Immunohistochemical analysis highlights the close proximity or partial overlap of both Fibulin-2 and ADAMTS-5 in breast tumor samples. Additionally, proteolytic products derived from a potential degradation of Fibulin-2 by ADAMTS-5 were also identified in these samples. Finally, we also show that the cleavage of Fibulin-2 by ADAMTS-5 is counteracted by ADAMTS-12, a metalloprotease that interacts with Fibulin-2. Overall, our results provide direct evidence indicating that Fibulin-2 is a novel substrate of ADAMTS-5 and that this proteolysis could alter the cellular microenvironment affecting the balance between protumor and antitumor effects associated to both Fibulin-2 and the ADAMTSs metalloproteases.

Fibulin-4 is associated with prognosis of endometrial cancer patients and inhibits cancer cell invasion and metastasis via Wnt/β-catenin signaling pathway

Fibulin-4, an extracellular glycoprotein, which plays significant roles in elastic fiber assembly, is correlated to the progression of some cancers. However, the role of fibulin-4 in endometrial cancer cell invasion and metastasis remains unexplored. In our study, fibulin-4 expression was assessed by immunohistochemistry (IHC) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in normal endometrial tissues and endometrial carcinoma tissues. Using single cell cloning, strongly, and weakly, invasive subclones were derived from KLE and Ishikawa endometrial carcinoma cell lines. RT-qPCR, western blotting, and immunocytochemistry (ICC) were used to assess mRNA and protein expressions of fibulin-4 in primary cultured endometrial cells, 4 types of endometrial cancer cell lines, and the different invasive subclones. Using lentivirus transfection, fibulin-4 shRNA and pLVX-fibulin-4 were constructed and used to infect the strongly and weakly invasive subclones. The effects of fibulin-4 on the biological characteristics of endometrial carcinoma cells were detected by cell functional assays in vitro and in vivo. Using Wnt signaling pathway inhibitor XAV-939 and activator LiCl, we detected the role of fibulin-4 in the Wnt/β-catenin pathway and the relationship with epithelial to mesenchymal transition (EMT). Fibulin-4 was decreased in endometrial carcinoma tissues, and loss of fibulin-4 expression was significantly related with poor differentiation, lymph node metastasis, and poor prognosis of endometrial carcinoma. Fibulin-4 significantly inhibited endometrial carcinoma cell proliferation, invasion, metastasis, and EMT through the Wnt/β-catenin pathway. Fibulin-4 has the ability to suppress endometrial cancer progression. These results can contribute to the development of a new potential therapeutic target for patients with endometrial carcinoma.

Loss of fibulin-2 expression is involved in the inhibition of breast cancer invasion and forms a new barrier in addition to the basement membrane

Previous studies have demonstrated that fibulin-2 may facilitate cancer cell invasion and metastasis during tumor progression. In the present study, immunohistochemical analyses of fibulin-2 and collagen IV expression in 35 patients with breast cancer were performed to define their localization and association with breast cancer tissue. Fibulin-2 was revealed to be expressed in all tissues surrounding the breast ducts and blood vessels in normal breast tissue, while its expression was not integrated in invasive ductal carcinoma or terminal duct-lobular unit. In malignant breast tissue, collagen IV was integrated around the duct, while fibulin-2 was expressed around collagen IV and was incomplete. These results demonstrated that fibulin-2 was associated with breast cancer invasion. Fibulin-2 expression decreased prior to basement membrane (BM) degradation, indicating that fibulin-2 forms an additional barrier around the BM. Therefore, it was proposed that fibulin-2 composes the general BM, which differs from the traditional BM. These results provide insight into extracellular matrix components and the involvement of fibulin-2 in tumor invasion and metastasis. Fibulin-2 was involved in the process of breast cancer development. It performed an important role in prevention of cancer cell penetration and metastasis.

Identification of novel methylated targets in colorectal cancer by microarray analysis and construction of co-expression network

The present study was conducted to investigate novel methylated targets in colorectal cancer (CRC). The mRNA expression profiles of GSE32323 in 17 cancer and non-cancerous tissues from CRC patients, as well as expression profiles of 5 CRC cell lines prior and subsequent to 5-aza-2′-deoxycytidine (5-aza-dC) treatment, were obtained from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) in 5 CRC cell lines prior and subsequent to 5-aza-dC treatment were combined with the CRC-specific gene expression profiling array data. Context likelihood of relatedness algorithm was used to construct the co-expression network of CRC-specific gene expression profile. A sub-network of identified reverse-overlapped DEGs was selected and underwent Kyoto Encyclopedia of Genes and Genomes Pathway Analysis. A total of 6 reverse-overlapped DEGs were identified. This present study verified fibulin 2 (FBLN2) and protein phosphatase 1 regulatory inhibitor subunit 14A (PPP1R14A) to be downregulated in the CRC tissue sample but upregulated in CRC cell lines following 5-aza-dC treatment. The identified reverse-overlapped DEGs were enriched in tumor-associated signaling pathways, including cellular tumor antigen p53, cell cycle and NOD-like receptor (NLR) signaling pathway. A total of 2 silenced genes with abnormal methylation in CRC were identified, including FBLN2 and PPP1R14A. The reverse-overlapped DEGs were enriched in p53, cell cycle and NLR signaling pathways, indicating that reverse-overlapped DEGs, particularly FBLN2 and PPP1R14A, may be important tumor suppressors and that these reverse-overlapped DEGs are inactivated by methylation in CRC.

Fibulin-4 promotes osteosarcoma invasion and metastasis by inducing epithelial to mesenchymal transition via the PI3K/Akt/mTOR pathway

This study explored the role of fibulin-4 in osteosarcoma progression and the possible signaling pathway involved. Fibulin-4 mRNA and protein expression in normal tissue, benign fibrous dysplasia, osteosarcoma, osteosarcoma cell lines, the normal osteoblastic cell line hFOB, and different invasive subclones were evaluated by immunohistochemistry (IHC) or immunocytochemistry (ICC) and real-time reverse transcriptase-polymerase chain reaction (real-time qRT-PCR). Using in vitro functional assays, we analyzed the invasive and proliferative abilities of different osteosarcoma cell lines and subclones with differing invasive potential. To assess the role of fibulin-4 in the invasion and metastasis of osteosarcoma cells, lentiviral vectors with fibulin-4 small hairpin RNA (shRNA) and pLVX-fibulin-4 were constructed and used to infect the highly invasive and low invasive subclones and osteosarcoma cell lines. The effects of fibulin-4 knockdown and upregulation on the biological behavior of osteosarcoma cells were investigated by functional in vitro and in vivo assays. The results revealed that fibulin-4 expression was upregulated in osteosarcoma, and was positively correlated with low differentiation, lymph node metastasis, and poor prognosis. Fibulin-4 was also found to be over-expressed in highly invasive cell lines and in the highly invasive subclones. Fibulin-4 could promote osteosarcoma cell invasion and metastasis by inducing EMT via the PI3K/AKT/mTOR pathway. Collectively, our findings demonstrate that fibulin-4 is a promoter of osteosarcoma development and progression, and suggest a novel therapeutic target for future studies.

Differential proteomics analysis of low- and high-grade of astrocytoma using iTRAQ quantification

Astrocytoma is one of the most common types of brain tumor, which is histologically and clinically classified into four grades (I–IV): I (pilocytic astrocytoma), II (diffuse astrocytoma), III (anaplastic astrocytoma), and IV (glioblastoma multiforme). A higher grade astrocytoma represents a worse prognosis and is more aggressive. In this study, we compared the differential proteome profile of astrocytoma from grades I to IV. The protein samples from clinical specimens of grades I, II, III, and IV astrocytoma were analyzed by two-dimensional liquid chromatography–tandem mass spectrometry and isobaric tags for relative and absolute quantitation and quantification. A total of 2,190 proteins were identified. Compared to grade I astrocytoma, 173 (12.4%), 304 (14%), and 462 (21.2%) proteins were aberrantly expressed in grades II, III, and IV, respectively. By bioinformatics analysis, the cell proliferation, invasion, and angiogenesis-related pathways increase from low- to high-grade of astrocytoma. Five differentially expressed proteins were validated by Western blot. Within them, matrix metalloproteinase-9 and metalloproteinase inhibitor 1 were upregulated in glioblastoma multiforme group; whereas fibulin-2 and -5 were downregulated in grade II/III/IV astrocytoma, and the negative expression was significantly associated with advanced clinical stage. Functional analysis showed that both fibulin-2 and -5 may exert an antitumor effect by inhibiting cell proliferation, in vitro migration/invasion in glioma cells. New molecular biomarkers are likely to be used for accurate classification of astrocytoma and likely to be the target for drug development.

ISOexpresso: a web-based platform for isoform-level expression analysis in human cancer

Background

Alternative splicing events that result in the production of multiple gene isoforms reveals important molecular mechanisms. Gene isoforms are often differentially expressed across organs and tissues, developmental stages, and disease conditions. Specifically, recent studies show that aberrant regulation of alternative splicing frequently occurs in cancer to affect tumor cell transformation and growth. While analysis of isoform expression is important for discovering tumor-specific isoform signatures and interpreting relevant genomic mutations, there is currently no web-based, easy-to-use, and publicly available platform for this purpose.

Description

We developed ISOexpresso to provide information regarding isoform existence and expression, which can be grouped by cancer vs. normal conditions, cancer types, and tissue types. ISOexpresso implements two main functions: First, the Isoform Expression View function creates visualizations for condition-specific RNA/isoform expression patterns upon query of a gene of interest. With this function, users can easily determine the major isoform (the most expressed isoform in a sample) of a gene with respect to the condition and check whether it matches the known canonical isoform. ISOexpresso outputs expression levels of all known transcripts to check alterations of expression landscape and to find potential tumor-specific isoforms. Second, the User Data Annotation function supports annotation of genomic variants to determine the most plausible consequence of a variation (e.g., an amino acid change) among many possible interpretations. As most coding sequence mutations are effective through the subsequent transcription and translation, ISOexpresso automatically prioritizes transcripts that act as backbones for mutation effect prediction by their relative expression. By employing ISOexpresso, we could investigate the consistency between the most expressed and known canonical/principal isoforms, as well as infer candidate tumor-specific isoforms based on their expression levels. In addition, we confirmed that ISOexpresso could easily reproduce previously known isoform expression patterns: recurrent observation of a major isoform across tissues, differential isoform expression patterns in a given tissue, and switching of major isoform during tumorigenesis.

Conclusions

ISOexpresso serves as a web-based, easy-to-use platform for isoform expression and alteration analysis based on large-scale cancer database. We anticipate that ISOexpresso will expedite formulation and confirmation of novel hypotheses by providing isoform-level perspectives on cancer research. The ISOexpresso database is available online at http://wiki.tgilab.org/ISOexpresso/.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2852-6) contains supplementary material, which is available to authorized users.

Whole-exome sequencing identifies MST1R as a genetic susceptibility gene in nasopharyngeal carcinoma

Multiple factors, including host genetics, environmental factors, and Epstein-Barr virus (EBV) infection, contribute to nasopharyngeal carcinoma (NPC) development. To identify genetic susceptibility genes for NPC, a whole-exome sequencing (WES) study was performed in 161 NPC cases and 895 controls of Southern Chinese descent. The gene-based burden test discovered an association between macrophage-stimulating 1 receptor (MST1R) and NPC. We identified 13 independent cases carrying the MST1R pathogenic heterozygous germ-line variants, and 53.8% of these cases were diagnosed with NPC aged at or even younger than 20 y, indicating that MST1R germline variants are relevant to disease early-age onset (EAO) (age of ≤20 y). In total, five MST1R missense variants were found in EAO cases but were rare in controls (EAO vs. control, 17.9% vs. 1.2%, P = 7.94 × 10(-12)). The validation study, including 2,160 cases and 2,433 controls, showed that the MST1R variant c.G917A:p.R306H is highly associated with NPC (odds ratio of 9.0). MST1R is predominantly expressed in the tissue-resident macrophages and is critical for innate immunity that protects organs from tissue damage and inflammation. Importantly, MST1R expression is detected in the ciliated epithelial cells in normal nasopharyngeal mucosa and plays a role in the cilia motility important for host defense. Although no somatic mutation of MST1R was identified in the sporadic NPC tumors, copy number alterations and promoter hypermethylation at MST1R were often observed. Our findings provide new insights into the pathogenesis of NPC by highlighting the involvement of the MST1R-mediated signaling pathways.

Integrin α9 gene promoter is hypermethylated and downregulated in nasopharyngeal carcinoma

Epigenetic silencing of tumor suppressor genes (TSGs) by promoter methylation can be an early event in the multi-step process of carcinogenesis. Human chromosome 3 contains clusters of TSGs involved in many cancer types including nasopharyngeal carcinoma (NPC), the most common cancer in Southern China. Among ten candidate TSGs identified in chromosome 3 using NotI microarray, ITGA9 and WNT7A could be validated. 5'-aza-2' deoxycytidine treatment restored the expression of ITGA9 and WNT7A in two NPC cell lines. Immunostaining showed strong expression of these genes in the membrane and cytoplasm of adjacent control nasopharyngeal epithelium cells, while they were weakly expressed in NPC tumor cells. The ITGA9 promoter showed marked differentially methylation between tumor and control tissue, whereas no differentially methylation could be detected for the WNT7A promoter. The expression level of ITGA9 in NPC tumors was downregulated 4.9-fold, compared to the expression in control. ITGA9 methylation was detected by methylation specific PCR (MSP) in 56% of EBV positive NPC-cases with 100% specificity. Taken together, this suggests that ITGA9 might be a TSG in NPC that is involved in tumor cell biology. The possibility of using ITGA9 methylation as a marker for early detection of NPC should further be explored.

The interplay of host genetic factors and Epstein-Barr virus in the development of nasopharyngeal carcinoma

The interplay between host cell genetics and Epstein-Barr virus (EBV) infection contributes to the development of nasopharyngeal carcinoma (NPC). Understanding the host genetic and epigenetic alterations and the influence of EBV on cell signaling and host gene regulation will aid in understanding the molecular pathogenesis of NPC and provide useful biomarkers and targets for diagnosis and therapy. In this review, we provide an update of the oncogenes and tumor suppressor genes associated with NPC, as well as genes associated with NPC risk including those involved in carcinogen detoxification and DNA repair. We also describe the importance of host genetics that govern the human leukocyte antigen (HLA) complex and immune responses, and we describe the impact of EBV infection on host cell signaling changes and epigenetic regulation of gene expression. High-power genomic sequencing approaches are needed to elucidate the genetic basis for inherited susceptibility to NPC and to identify the genes and pathways driving its molecular pathogenesis.

Identification of recurrent regulated alternative splicing events across human solid tumors

Cancer is a complex disease that involves aberrant gene expression regulation. Discriminating the modified expression patterns driving tumor biology from the many that have no or little contribution is important for understanding cancer molecular basis. Recurrent deregulation patterns observed in multiple cancer types are enriched for such driver events. Here, we studied splicing alterations in hundreds of matched tumor and normal RNA-seq samples of eight solid cancer types. We found hundreds of cassette exons for which splicing was altered in multiple cancer types and identified a set of highly frequent altered splicing events. Specific splicing regulators, including RBFOX2, MBNL1/2 and QKI, appear to account for many splicing alteration events in multiple cancer types. Together, our results provide a first global analysis of regulated splicing alterations in cancer and identify common events with a potential causative role in solid tumor development.

Fibulin-4 is associated with tumor progression and a poor prognosis in ovarian carcinomas

Background

Fibulin-4, a member of the fibulin family of extracellular glycoproteins, is implicated in the progressions of some cancers. However, no information has been available to date regarding the function of fibulin-4 in ovarian carcinoma progression.

Methods

In this study, fibulin-4 mRNA and protein expression in normal ovarian tissue, ovarian tumor, high invasive subclones and low invasive subclones were evaluated by immunohistochemistry and real time reverse transcriptase-polymerase chain reaction (RT-PCR). The serum levels of fibulin-4, cancer antigen 125 (CA-125) and cerbohydrate antigen 199 (CA19-9) in patients with ovarian tumor were measured by enzyme-linked immunosorbent assay and electrochemiluminescent immunoassay. To assess the angiogenic properties of fibulin-4, vascular endothelial growth factor (VEGF) expression and tumor microvessel density were analyzed in ovarian carcinoma by immunohistochemistry.

Results

Fibulin-4 expression was upregulated in ovarian carcinoma, and positively correlated with MVD and VEGF expression. Fibulin-4 overexpression was significantly associated with advanced stage, low differentiation, lymph node metastasis and poor prognosis in patients with ovarian cancer. The serum levels of fibulin-4, CA-125 and CA19-9 in patients with ovarian carcinoma were much higher than those with benign ovarian tumors and normal controls. Compared to CA-125 and CA19-9, fibulin-4 had better diagnostic sensitivity and specificity.

Conclusions

Fibulin-4 is a novel gene that is found overexpressed in ovarian cancer and associated with poor prognostic clinicopathologic features. This study shows that fibulin-4 may serve as a new prognostic factor and as a potential therapeutic target for patients with ovarian cancer in the future.

Novel lentiviral-inducible transgene expression systems and versatile single-plasmid reporters for in vitro and in vivo cancer biology studies

Many of the cancer cell lines derived from solid tumors are difficult to transfect using commonly established transfection approaches. This hurdle for some DNA transfection systems has hindered cancer biology studies. Moreover, there are limited tools for studying pathway activities. Therefore, highly efficient improved gene transfer and versatile genetic tools are required. In this study, we established and developed a comprehensive set of new lentiviral tools to study gene functions and pathway activities. Using the optimized conditions, cancer cell lines achieved >90% transduction efficiency. Novel lentiviral doxycycline-regulated pTet-IRES-EGFP (pTIE) systems for transgene expression and TRE reporters used for pathway activity determination were developed and tested. The pTIE Tet-Off system showed in vitro doxycycline-sensitive responses with low or undetectable leakage of protein expression and in vivo tumor suppression as illustrated using candidate tumor suppressors, Fibulin-2 and THY1. In contrast, the Tet-On system showed dose-dependent responses. The pTRE-EGFP (pTE) and pTRE-FLuc-EF1α-RLuc (pT-FER) reporters with the NFκB p65 subunit consensus sequence showed GFP and firefly luciferase responses, which were directly correlated with TNFα stimulation, respectively. Taken together, these newly developed lentiviral systems provide versatile in vitro and in vivo platforms to strengthen our capabilities for cancer biology studies.

Blockage of LMP1-modulated store-operated Ca(2+) entry reduces metastatic potential in nasopharyngeal carcinoma cell

Epstein-Barr virus (EBV)-encoded latent membrane proteins (LMPs) expedite progression of EBV-relevant cancers. Of the full set of LMPs, latent membrane protein 1 (LMP1) was identified to uniquely augment store-operated Ca(2+) entry (SOCE). Previously, we reported that the suppression of SOCE exhibited inhibitory effects on cell migration and the extravasation from vasculature in EBV-negative nasopharyngeal carcinoma (NPC) cells. In this follow-up study, we aimed to expand our understanding of the modulation of SOCE by LMP1 and test the possibility that blockage of LMP1-modulated SOCE affects the LMP1-promoted metastatic potential. Here we showed that suppressions of the LMP1-boosted SOCE blunted the LMP1-promoted cell migration, VEGF-mediated angiogenesis and permeabilization in vitro. Blockage of SOCE inhibited vasculature-invasion of circulating cells and distant metastatic colonization in vivo. Notably, utilizing VEGFR2-EGFP-tag zebrafish we revealed that the LMP1-expressing cells arrested in a small-caliber vessel mobilized surrounding endothelial cells to facilitate vasculature-invasion. Thus, the LMP1-boosted SOCE promotes metastatic potential of NPC cells by solidifying their collaborations with the nearby non-cancer cells through the manipulation of oncogenic Ca(2+) signaling. Our study highlights the advantage of using both conventional mammal and transgenic zebrafish for developing a novel therapeutic strategy targeting the multiple steps of invasion-metastasis cascade.