Identification of epithelial membrane protein 2 (EMP2) as a molecular marker and correlate for angiogenesis in meningioma

The Multifaceted Role of Epithelial Membrane Protein 2 in Cancer: from Biomarker to Therapeutic Target

Tetraspanin superfamily proteins not only facilitate the trafficking of specific proteins to distinct plasma membrane domains but also influence cell-to-cell and cell-extracellular matrix interactions. Among these proteins, Epithelial Membrane Protein 2 (EMP2), a member of the growth arrest-specific gene 3/peripheral myelin protein 22 (GAS3/PMP22) family, is known to affect key cellular processes. Recent studies have revealed that EMP2 modulates critical signaling pathways and interacts with adhesion molecules and growth factor receptors, underscoring its potential as a biomarker for cancer diagnosis and prognosis. These findings suggest that EMP2 expression patterns could provide valuable insights into tumorigenesis and metastasis. Moreover, EMP2 has emerged as a promising therapeutic target, with approaches aimed at inhibiting or modulating its activity showing potential to disrupt tumor growth and metastasis. This review provides a comprehensive overview of recent advances in understanding the multifaceted roles of EMP2 in cancer, with a focus on its underlying mechanisms and clinical significance.

Aggf1 Specifies Hemangioblasts at the Top of Regulatory Hierarchy via Npas4l and mTOR-S6K-Emp2-ERK Signaling

BACKGROUND

Hemangioblasts are mesoderm-derived multipotent stem cells for differentiation of all hematopoietic and endothelial cells in the circulation system. However, the underlying molecular mechanism is poorly understood.

METHODS

CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (type II CRISPR RNA-guided endonuclease) editing was used to develop aggf1-/- and emp2-/- knockout zebra fish. Whole-mount in situ hybridization and transgenic Tg(gata1-EGFP [enhanced green fluorescent protein]), Tg(mpx-EGFP), Tg(rag2-DsRed [discosoma sp. red fluorescent protein]), Tg(cd41-EGFP), Tg(kdrl-EGFP), and Tg(aggf1-/-;kdrl-EGFP) zebra fish were used to examine specification of hemangioblasts and hematopoietic stem and progenitor cells (HSPCs), hematopoiesis, and vascular development. Quantitative real-time polymerase chain reaction and Western blot analyses were used for expression analysis of genes and proteins.

RESULTS

Knockout of aggf1 impaired specification of hemangioblasts and HSPCs, hematopoiesis, and vascular development in zebra fish. Expression of npas4l/cloche-the presumed earliest marker for hemangioblast specification-was significantly reduced in aggf1-/- embryos and increased by overexpression of aggf1 in embryos. Overexpression of npas4l rescued the impaired specification of hemangioblasts and HSPCs and development of hematopoiesis and intersegmental vessels in aggf1-/- embryos, placing aggf1 upstream of npas4l in hemangioblast specification. To identify the underlying molecular mechanism, we identified emp2 as a key aggf1 downstream gene. Similar to aggf1, emp2 knockout impaired the specification of hemangioblasts and HSPCs, hematopoiesis, and angiogenesis by increasing the phosphorylation of ERK1/2 (extracellular signal-regulated protein kinase 1/2). Mechanistic studies showed that aggf1 knockdown and knockout significantly decreased the phosphorylated levels of mTOR (mammalian target of rapamycin) and p70 S6K (ribosomal protein S6 kinase), resulting in reduced protein synthesis of Emp2 (epithelial membrane protein 2), whereas mTOR activator MHY1485 (4,6-dimorpholino-N-(4-nitrophenyl)-1,3,5-triazin-2-amine) rescued the impaired specification of hemangioblasts and HSPCs and development of hematopoiesis and intersegmental vessels and reduced Emp2 expression induced by aggf1 knockdown.

CONCLUSIONS

These results indicate that aggf1 acts at the top of npas4l and becomes the earliest marker during specification of hemangioblasts. Our data identify a novel signaling axis of Aggf1 (angiogenic factor with G-patch and FHA domain 1)-mTOR-S6K-ERK1/2 for specification of hemangioblasts and HSPCs, primitive and definitive hematopoiesis, and vascular development. Our findings provide important insights into specification of hemangioblasts and HSPCs essential for the development of the circulation system.

Epithelial membrane protein 2 (EMP2): A systematic review of its implications in pathogenesis

OBJECTIVES

Epithelial membrane protein 2 (EMP2) is a cell surface protein composed of approximately 160 amino acids and encoded by the growth arrest-specific 3 (GAS3)/peripheral myelin protein 22 kDa (PMP22) gene family. Although EMP2 expression has been investigated in several diseases, much remains unknown regarding its mechanism of action and the extent of its role in pathogenesis. Our aim was to perform a systematic review on the involvement of EMP2 in disease processes and the current usage of anti-EMP2 therapies.

METHODS

A Boolean search of the English-language medical literature was performed. PubMed, Scopus, Cochrane, and Web of Science were used to identify relevant citations. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

52 studies met the inclusion criteria for qualitative analysis. Of those, 28 (53.8%) were human-only studies, 11 (21.2%) were animal-only studies, and 13 (25%) studies included both human and animal models. Furthermore, 34 (65.4%) studies focused on EMP2's role in neoplasms, while the remaining 18 (34.6%) articles evaluated its role in other pathologies.

CONCLUSION

Overall, the evidence suggests the mechanisms of action of EMP2 are context dependent. Promising results have been produced by utilizing EMP2 as a biomarker and therapeutic target. More studies are warranted to better understand the mechanism and comprehend the role of EMP2 in the pathogenesis of diseases.

Identification of immune and stromal cell infiltration-related gene signature for prognosis prediction in acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a common and life-threatening hematologic malignancy, its occurrence and progression are closely related to immune/stromal cell infiltration in the bone marrow (BM) microenvironment. However, no studies have described an immune/stromal cell infiltration-related gene (ISCIRG)-based prognostic signature for ALL. A total of 444 patients involving 437 bulk and 7 single-cell RNA-seq datasets were included in this study. Eligible datasets were searched and reviewed from the database of TCGA, TARGET project and GEO. Then an integrated bioinformatics analysis was performed to select optimal prognosis-related genes from ISCIRGs, construct a nomogram model for predicting prognosis, and assess the predictive power. After LASSO and multivariate Cox regression analyses, a seven ISCIRGs-based signature was proved to be able to significantly stratify patients into high- and low-risk groups in terms of OS. The seven genes were confirmed that directly related to the composition and status of immune/stromal cells in BM microenvironment by analyzing bulk and single-cell RNA-seq datasets. The calibration plot showed that the predicted results of the nomogram were consistent with the actual observation results of training/validation cohort. This study offers a reference for future research regarding the role of ISCIRGs in ALL and the clinical care of patients.

Epithelial membrane protein 2 (Emp2) modulates innate immune cell population recruitment at the maternal-fetal interface

Epithelial membrane protein 2 (EMP2) is a tetraspan membrane protein that has been revealed in cancer and placental models to mediate a number of vascular responses. Recently, Emp2 modulation has been shown to have an immunologic effect on uterine NK cell recruitment in the mouse placenta. Given the importance of immune cell populations on both placental vascularization and maternal immune tolerance of the developing fetus, we wanted to better characterize the immunologic effects of Emp2 at the placental-fetal interface. We performed flow cytometry of WT and Emp2 KO C57Bl/6 mouse uterine horns at GD12.5 to characterize immune cell populations localized to the various components of the maternal-fetal interface. We found that Emp2 KO decidua and placenta showed an elevated overall percentage of CD45+ cells compared to WT. Characterization of CD45+ cells in the decidua of Emp2 KO dams revealed an increase in NK cells, whereas in the placenta, Emp2 KO dams showed an increased percentage of M1 macrophages (with an increased ratio of M1/M2 macrophages). Given the differences detected in uNK cell populations in the decidua, we further characterized the interaction between Emp2 genetic KO and NK cell deletion via anti-asialo GM1 antibody injections. While the double knock-out of Emp2 and NK cells did not alter individual pup birthweight, it significantly reduced total litter weight and size by ∼50 %. In conclusion, Emp2 appears to regulate uNK and macrophage cell populations in pregnancy.

The role of mRNA in the development, diagnosis, treatment and prognosis of neural tumors

Neural tumors can generally be divided into central nervous system tumors and peripheral nervous tumors. Because this type of tumor is located in the nerve, even benign tumors are often difficult to remove by surgery. In addition, the majority of neural tumors are malignant, and it is particular the same for the central nervous system tumors. Even treated with the means such as chemotherapy and radiotherapy, they are also difficult to completely cure. In recent years, an increasingly number of studies have focused on the use of mRNA to treat tumors, representing an emerging gene therapy. The use of mRNA can use the expression of some functional proteins for the treatment of genetic disorders or tissue repair, and it can also be applied to immunotherapy through the expression of antigens, antibodies or receptors. Therefore, although these therapies are not fully-fledged enough, they have a broad research prospect. In addition, there are many ways to treat tumors using mRNA vaccines and exosomes carrying mRNA, which have drawn much attention. In this study, we reviewed the current research on the role of mRNA in the development, diagnosis, treatment and prognosis of neural tumors, and examine the future research prospects of mRNA in neural tumors and the opportunities and challenges that will arise in the future application of clinical treatment.

Increased epithelial membrane protein 2 expression in glioblastoma after treatment with bevacizumab

Background

Antiangiogenic therapy with bevacizumab has failed to provide substantial gains in overall survival. Epithelial membrane protein 2 (EMP2) is a cell surface protein that has been previously shown to be expressed in glioblastoma, correlate with poor survival, and regulate neoangiogenesis in cell lines. Thus, the relationship between bevacizumab and EMP2 was investigated.

Methods

Tumor samples were obtained from 12 patients with newly diagnosed glioblastoma at 2 time points: (1) during the initial surgery and (2) during a subsequent surgery following disease recurrence post-bevacizumab treatment. Clinical characteristics and survival data from these patients were collected, and tumor samples were stained for EMP2 expression. The IVY Glioblastoma Atlas Project database was used to evaluate EMP2 expression levels in 270 samples by differing histological areas of the tumor.

Results

Patients with high EMP2 staining at initial diagnosis had decreased progression-free and overall survival after bevacizumab (median progression-free survival 4.6 months vs 5.9 months; log-rank P = .076 and overall survival 7.7 months vs 14.4 months; log-rank P = .011). There was increased EMP2 staining in samples obtained after bevacizumab treatment in both unpaired (mean H-score 2.31 vs 1.76; P = .006) and paired analyses (mean difference 0.571; P = .019). This expression increase correlated with length of bevacizumab therapy (R ²  = 0.449; Pearson P = .024).

Conclusions

Bevacizumab treatment increased EMP2 protein expression. This increase in EMP2 correlated with reduced mean survival time post-bevacizumab therapy. We hypothesize a role of EMP2 in clinical bevacizumab resistance and as a potential antiangiogenic therapeutic target in glioblastoma.