Egfl7 promotes tumor escape from immunity

A Pan-Cancer Study of Epidermal Growth Factor-Like Domains 6/7/8 as Therapeutic Targets in Cancer

With highly homologous epidermal growth factor (EGF)-like (EGFL) domains, the members of the EGFL family play crucial roles in growth, invasion, and metastasis of tumors and are closely associated with the apoptosis of tumor cells and tumor angiogenesis. Furthermore, their contribution to immunoreaction and tumor microenvironment is highly known. In this study, a comprehensive analysis of EGFL6, -7, and -8 was performed on the basis of their expression profiles and their relationship with the rate of patient survival. Through a pan-cancer study, their effects were correlated with immune subtypes, tumor microenvironment, and drug resistance. Using The Cancer Genome Atlas pan-cancer data, expression profiles of EGFL6, -7, and -8, and their association with the patient survival rate and tumor microenvironment were analyzed in 33 types of cancers. The expression of the EGFL family was different in different cancer types, revealing the heterogeneity among cancers. The results showed that the expression of EGFL8 was lower than EGFL6 and EGFL7 among all cancer types, wherein EGFL7 had the highest expression. The univariate Cox proportional hazard regression model showed that EGFL6 and EGFL7 were the risk factors to predict poor prognosis of cancers. Survival analysis was then used to verify the relationship between gene expression and patient survival. Furthermore, EGFL6, EGFL7, and EGFL8 genes revealed a clear association with immune infiltrate subtypes; they were also related to the infiltration level of stromal cells and immune cells with different degrees. Moreover, they were negatively correlated with the characteristics of cancer stem cells measured by DNAs and RNAs. In addition, EGFL6, -7, and -8 were more likely to contribute to the resistance of cancer cells. Our systematic analysis of EGFL gene expression and their correlation with immune infiltration, tumor microenvironment, and prognosis of cancer patients emphasized the necessity of studying each EGFL member as a separate entity within each particular type of cancer. Simultaneously, EGFL6, -7, and -8 signals were verified as promising targets for cancer therapies, although further laboratory validation is still required.

MicroRNA-126 exerts antitumor functions in ovarian cancer by targeting EGFL7 and affecting epithelial-to-mesenchymal transition and ERK/MAPK signaling pathway

Ovarian cancer (OC) is a common gynecological malignant carcinoma worldwide. Accumulating research has revealed that multiple microRNAs (miRNAs) are abnormally expressed at different levels in various malignancies, playing vital roles in tumorigenesis. This study investigated the regulatory functions and potential mechanism of miR-126 in OC proliferation, invasion and migration. It was found that miR-126 was prominently downregulated in OC. Moreover, the decrease of miR-126 promoted the aggressive phenotypes and indicated poor prognosis of OC patients. Functional assays demonstrated that restoration of miR-126 dramatically repressed OC cell proliferation, migration and invasion. Furthermore, luciferase reporter assay was conducted to verify putative binding sites of miR-126 in the epidermal growth factor-like domain 7 (EGFL7) 3 untranslated region (3'UTR), indicating that EGFL7 was a target gene of miR-126 in OC cells. It was further discovered that miR-126 exerts its function on regulating ERK/MAPK pathway and epithelial-to-mesenchymal transition (EMT) in OC cells. The above findings suggested that miR-126 served as a cancer suppressor in OC, suggesting a promising application of miR-126 in the clinical diagnosis and therapeutics of OC.

Novel Expression of EGFL7 in Osteosarcoma and Sensitivity to Cisplatin

Epidermal growth factor-like domain 7 (EGFL7) is a protein specifically secreted by blood vessel endothelial cells, which plays an important role in angiogenesis. Considering the aberrant secretion of EGFL7 in osteosarcoma (OS) has not yet been elucidated, this study investigated the secretion of EGFL7 in OS and the changes in its secretion after chemotherapy. We observed increased varying secretion of EGFL7 in OS tissues compared with chondrosarcoma (CS) tissues. OS cell lines and HUVECs showed higher EGFL7 mRNA and protein expression than SW1353, with OS cells expressing the highest levels. In patient samples, EGFL7 was highly expressed in the cytoplasm of OS tumor cells and vascular endothelium cells. This overexpression was abolished in OS cell and tumor tissues when treated with chemotherapy. This study is a pioneering study to investigate EGFL7 expression and localization in human OS tissues and cell. Overexpression of EGFL-7 in response to chemotherapy suggests that it can be used as a therapeutic target for OS.

EGFL7 reduces CNS inflammation in mouse

Extracellular matrix (ECM) proteins secreted by blood-brain barrier (BBB) endothelial cells (ECs) are implicated in cell trafficking. We discovered that the expression of ECM epidermal growth factor-like protein 7 (EGFL7) is increased in the CNS vasculature of patients with multiple sclerosis (MS), and in mice with experimental autoimmune encephalomyelitis (EAE). Perivascular CD4 T lymphocytes colocalize with ECM-bound EGFL7 in MS lesions. Human and mouse activated T cells upregulate EGFL7 ligand αvβ3 integrin and can adhere to EGFL7 through integrin αvβ3. EGFL7-knockout (KO) mice show earlier onset of EAE and increased brain and spinal cord parenchymal infiltration of T lymphocytes. Importantly, EC-restricted EGFL7-KO is associated with a similar EAE worsening. Finally, treatment with recombinant EGFL7 improves EAE, reduces MCAM expression, and tightens the BBB in mouse. Our data demonstrate that EGFL7 can limit CNS immune infiltration and may represent a novel therapeutic avenue in MS.

Endothelial cells release extracellular matrix components that regulate inflammation. Here the authors demonstrate that the extracellular matrix component epidermal growth factor-like protein 7 regulates inflammation in experimental autoimmune encephalomyelitis in the mouse.

Effect and Mechanism of EGFL7 Downregulation in Human Osteosarcoma Cells on the Biological Function of Co-cultured HUVEC

Background:

Even though epidermal growth factor-like domain 7 is known to be overexpressed in osteosarcoma and is associated with poor clinical outcome, few reports are available regarding its mechanism.

Aims:

The objective of this study was to explore the effect and mechanism of downregulating epidermal growth factor-like domain 7 expression in a human osteosarcoma cell line on the biological function of co-cultured human umbilical vein endothelial cells.

Study Design:

Cell study.

Methods:

In the present study, human osteosarcoma cell lines U2OS, Saos-2, HOS, and MG63, and normal human osteoblasts were cultured in Dulbecco’s Modified Eagle Medium containing 10% fetal bovine serum and 1x antibiotics at 37 °C and 5% CO₂ in an incubator. Of the four osteosarcoma cell lines, U2OS expresses the highest level of epidermal growth factor-like domain 7 mRNA as determined using quantitative reverse transcription polymerase chain reaction. With the knockdown of epidermal growth factor-like domain 7 in U2OS and human umbilical vein endothelial cells by lentivirus, the proliferation and apoptosis of U2OS and human umbilical vein endothelial cells were investigated using MTT and flow cytometry assays. After the co-culture of human umbilical vein endothelial cells and epidermal growth factor-like domain 7-knockdown U2OS, the in vitro effects on cell proliferation, apoptosis, adhesion, migration, and the angiogenic ability of human umbilical vein endothelial cells were detected using MTT, flow cytometry, Transwell, and tube formation assays, respectively. The expressions of phosphoinositide 3-kinase, phospho-Akt, total Akt, and vascular endothelial growth factor in human umbilical vein endothelial cells were detected using western blot assay.

Results:

Lentivirus with epidermal growth factor-like domain 7 shRNA could not significantly affect the proliferation and apoptosis of both U2OS and human umbilical vein endothelial cells, whereas the knockdown of epidermal growth factor-like domain 7 in U2OS could significantly inhibit the migration, adhesion, and angiogenic ability of co-cultured human umbilical vein endothelial cells. In addition, the expressions of phosphoinositide 3-kinase, phospho-Akt, and vascular endothelial growth factor in human umbilical vein endothelial cells decreased after co-culturing with epidermal growth factor-like domain 7-knockdown U2OS.

Conclusion:

Epidermal growth factor-like domain 7-knockdown U2OS cells inhibit the migration, adhesion, and angiogenesis of co-cultured human umbilical vein endothelial cells by diminishing phosphoinositide 3-kinase, Akt signaling pathway activity and vascular endothelial growth factor expression.

Molecular characterization and expression analysis of mouse epidermal growth factor-like domain 8

Epidermal growth factor (EGF)-like (EGFL) domain, a common structural module in numerous secreted or transmembrane proteins, is generally involved in protein-protein interactions. To date, several EGFL proteins have been identified and characterized, but little is known about EGFL domain 8 (EGFL8). The present study reported the molecular characterization and expression analysis of EGFL8 in mice. Mouse EGFL8 amplified using a reverse transcription-polymerase chain reaction approach was sequenced and characterized. Mouse EGFL8 encodes a protein of 293 amino acids with two EGFL domains, an Emilin-like domain and a Ca(2+)-binding EGFL domain, which has a molecular mass of 32 kDa. The coding sequence has a high degree of amino acid sequence identity across species, and the EGFL domain has been highly conserved in various species during evolutionary radiation. A phylogenetic tree calculated using the neighbor-joining method revealed that EGFL8 and EGFL7 are more closely associated with each other than either is to EGFL3, and they cluster with EGFL6. It was found that mouse EGFL8 protein was highly expressed in diverse mouse tissue types, including the thymus, lymph nodes, testis, ovaries, epididymis, ductus deferens, ileum, colon, stomach, esophagus, lung, uterus, urinary bladder, skin, spleen, adrenal glands and penis. These results are of great use in understanding the biological roles of mouse EGFL8 for further study.

Intra-tumoural vessel area estimated by expression of epidermal growth factor-like domain 7 and microRNA-126 in primary tumours and metastases of patients with colorectal cancer: a descriptive study

Background

Understanding the biological properties of potential drug targets are important. This is especially true for anti-angiogenic therapies in the search for potential biomarkers. The aim of the present descriptive study was to analyse the intra-tumoural expressions of epidermal growth factor-like domain 7 (EGFL7) and microRNA-126 (miRNA-126) in primary tumours from patients with stage II-IV colorectal cancer (CRC) and in paired samples of primary tumours, regional lymph node metastases and distant metastases.

Methods

A total of 126 patients were included. Analyses were performed on resections of primary tumours, regional lymph node metastases, and large needle biopsies from distant metastases. EGFL7 was analysed by immunohistochemistry (IHC) and miRNA-126 by in situ hybridization (ISH). Both biomarkers were quantified by image guided analyses to determine the relative fraction estimates of vessel areas (VA).

Results

The intra-tumoural EGFL7 VA was significantly higher in primary tumours from patients with recurrent disease than in patients without relapse in both stage II and III, p = 0.019 and p = 0.001, respectively. The EGFL7 VA was significantly higher and the miRNA-126 VA significantly lower in regional lymph node metastases compared to primary tumours, p = 0.01 and p < 10⁻⁶, respectively. Furthermore, the miRNA-126 VA in liver metastases was significantly lower than in the primary tumours, p = 0.02.

Conclusion

The intra-tumoural expression of EGFL7 in early stages of CRC may influence the risk of post-surgical recurrence. Differential expression of miRNA-126 seems more pronounced in disseminated disease, which supports its role as a regulator in the metastatic process.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-014-0359-y) contains supplementary material, which is available to authorized users.

Epidermal growth factor-like domain 7 predicts response to first-line chemotherapy and bevacizumab in patients with metastatic colorectal cancer

The number of approved antiangiogenic drugs is constantly growing and emphasizes the need for predictive biomarkers. The aim of this study was to analyze the predictive value of epidermal growth factor-like domain 7 (EGFL7) and microRNA-126 (miR126) to first-line chemotherapy combined with bevacizumab, in patients with metastatic colorectal cancer (mCRC). A total of 158 patients from two different, but comparable, cohorts were included. Analyses were performed on tumor tissue from the primary tumor either based on a whole-tumor resection or an endoscopic biopsy. EGFL7 was analyzed by immunohistochemistry (IHC) and miR126 by in situ hybridization (ISH). Both biomarkers were quantified by image-guided analyses. Endpoints were response rate (RR) and progression-free survival (PFS). The EGFL7 vessel area (VA) in tumor resections was closely related to treatment response with a median EGFL7 VA in responding patients of 4 [95% confidence interval (CI), 4-6] compared with 8.5 (95% CI, 7-11) in nonresponders, P = 0.0008. This difference translated into a borderline significant difference in PFS (P = 0.06). Furthermore, a significant relationship between high EGFL7 VA and KRAS mutation was detected (P = 0.049). The results showed no significant relationship between the miR126 VA and the clinical endpoints. Our study suggests a predictive value of EGFL7 in regard to first-line chemotherapy and bevacizumab in patients with mCRC and supports the mechanism of a dual blocking of the vascular endothelial growth factor-A and EGFL7 axis in this setting.

Genes Downregulated in Endometriosis Are Located Near the Known Imprinting Genes

There is now accumulating evidence that endometriosis is a disease associated with an epigenetic disorder. Genomic imprinting is an epigenetic phenomenon known to regulate DNA methylation of either maternal or paternal alleles. We hypothesize that hypermethylated endometriosis-associated genes may be enriched at imprinted gene loci. We sought to determine whether downregulated genes associated with endometriosis susceptibility are associated with chromosomal location of the known paternally and maternally expressed imprinting genes. Gene information has been gathered from National Center for Biotechnology Information database geneimprint.com. Several researchers have identified specific loci with strong DNA methylation in eutopic endometrium and ectopic lesion with endometriosis. Of the 29 hypermethylated genes in endometriosis, 19 genes were located near 45 known imprinted foci. There may be an association of the genomic location between genes specifically downregulated in endometriosis and epigenetically imprinted genes.