EMP1 inhibits nasopharyngeal cancer cell growth and metastasis through induction apoptosis and angiogenesis

EMP1 correlated with cancer progression and immune characteristics in pan-cancer and ovarian cancer

This study examines the prognostic role and immunological relevance of EMP1 (epithelial membrane protein-1) in a pan-cancer analysis, with a focus on ovarian cancer. Utilizing data from TCGA, CCLE, and GTEx databases, we assessed EMP1 mRNA expression and its correlation with tumor progression, prognosis, and immune microenvironment across various cancers. Our results indicate that EMP1 expression is significantly associated with poor prognosis in multiple cancer types, including ovarian, bladder, testicular, pancreatic, breast, brain, and uveal melanoma. Immune-related analyses reveal a positive correlation between EMP1 and immune cell infiltration, particularly neutrophils, macrophages, and dendritic cells, as well as high expression of immune checkpoint such as CD274, HAVCR2, IL10, PDCD1LG2, and TGFB1 in most tumors. In vivo experiments confirm that EMP1 promotes ovarian cancer cell proliferation, metastasis, and invasion. In conclusion, EMP1 emerges as a potential prognostic biomarker and therapeutic target in various cancers, particularly ovarian cancer, due to its influence on tumor progression and immune cell dynamics. Further research is warranted to elucidate the precise mechanisms of EMP1 in cancer biology and to translate these findings into clinical applications.

Differentially Expressed Genes, miRNAs and Network Models: A Strategy to Shed Light on Molecular Interactions Driving HNSCC Tumorigenesis

Head and neck squamous cell carcinoma (HNSCC) is among the most common cancer worldwide, accounting for hundreds thousands deaths annually. Unfortunately, most patients are diagnosed in an advanced stage and only a percentage respond favorably to therapies. To help fill this gap, we hereby propose a retrospective in silico study to shed light on gene-miRNA interactions driving the development of HNSCC. Moreover, to identify topological biomarkers as a source for designing new drugs. To achieve this, gene and miRNA profiles from patients and controls are holistically reevaluated using protein-protein interaction (PPI) and bipartite miRNA-target networks. Cytoskeletal remodeling, extracellular matrix (ECM), immune system, proteolysis, and energy metabolism have emerged as major functional modules involved in the pathogenesis of HNSCC. Of note, the landscape of our findings depicts a concerted molecular action in activating genes promoting cell cycle and proliferation, and inactivating those suppressive. In this scenario, genes, including VEGFA, EMP1, PPL, KRAS, MET, TP53, MMPs and HOXs, and miRNAs, including mir-6728 and mir-99a, emerge as key players in the molecular interactions driving HNSCC tumorigenesis. Despite the heterogeneity characterizing these HNSCC subtypes, and the limitations of a study pointing to relationships that could be context dependent, the overlap with previously published studies is encouraging. Hence, it supports further investigation for key molecules, both those already and not correlated to HNSCC.

Expression of EMP 1, 2, and 3 in Adrenal Cortical Neoplasm and Pheochromocytoma

The purpose of this study is to investigate the expression of the epithelial membrane proteins (EMP) 1, 2, and 3 in adrenal gland neoplasm and to explore the broader implications of this. Tissue microarrays were constructed for 132 cases of adrenal cortical neoplasms (ACN) (adrenal cortical adenoma (115 cases), and carcinoma (17 cases)) and 189 cases of pheochromocytoma. Immunohistochemical staining was performed to identify EMP 1, 2, and 3, and was compared with clinicopathological parameters. The H-score of EMP 3 (p < 0.001) was higher in pheochromocytoma when compared to that of ACN, and the H-score of EMP 1 (p < 0.001) and EMP 3 (p < 0.001) was higher in adrenal cortical carcinomas when compared to that of adrenal cortical adenomas. A higher EMP 1 H-score was observed in pheochromocytomas with a GAPP score ≥3 (p = 0.018). In univariate analysis, high levels of EMP 1 and EMP 3 expression in ACN were associated with shorter overall survival (p = 0.001). Differences were observed in the expression of EMPs between ACN and pheochromocytoma. EMPs are associated with malignant tumor biology in adrenal cortical neoplasm and pheochromocytoma, suggesting the role of a prognostic and/or predictive factor for EMPs in adrenal tumor.

Molecular differences of angiogenic versus vessel co-opting colorectal cancer liver metastases at single-cell resolution

BACKGROUND

Colorectal cancer liver metastases (CRCLM) are associated with a poor prognosis, reflected by a five-year survival rate of 14%. Anti-angiogenic therapy through anti-VEGF antibody administration is one of the limited therapies available. However, only a subgroup of metastases uses sprouting angiogenesis to secure their nutrients and oxygen supply, while others rely on vessel co-option (VCO). The distinct mode of vascularization is reflected by specific histopathological growth patterns (HGPs), which have proven prognostic and predictive significance. Nevertheless, their molecular mechanisms are poorly understood.

METHODS

We evaluated CRCLM from 225 patients regarding their HGP and clinical data. Moreover, we performed spatial (21,804 spots) and single-cell (22,419 cells) RNA sequencing analyses to explore molecular differences in detail, further validated in vitro through immunohistochemical analysis and patient-derived organoid cultures.

RESULTS

We detected specific metabolic alterations and a signature of WNT signalling activation in metastatic cancer cells related to the VCO phenotype. Importantly, in the corresponding healthy liver of CRCLM displaying sprouting angiogenesis, we identified a predominantly expressed capillary subtype of endothelial cells, which could be further explored as a possible predictor for HGP relying on sprouting angiogenesis.

CONCLUSION

These findings may prove to be novel therapeutic targets to the treatment of CRCLM, in special the ones relying on VCO.

Unraveling the structures, functions and mechanisms of epithelial membrane protein family in human cancers

Peripheral myelin protein 22 (PMP22) and epithelial membrane proteins (EMP-1, -2, and -3) belong to a small hydrophobic membrane protein subfamily, with four transmembrane structures. PMP22 and EMPs are widely expressed in various tissues and play important roles in cell growth, differentiation, programmed cell death, and metastasis. PMP22 presents its highest expression in the peripheral nerve and participates in normal physiological and pathological processes of the peripheral nervous system. The progress of molecular genetics has shown that the genetic changes of the PMP22 gene, including duplication, deletion, and point mutation, are behind various hereditary peripheral neuropathies. EMPs have different expression patterns in diverse tissues and are closely related to the risk of malignant tumor progression. In this review, we focus on the four members in this protein family which are related to disease pathogenesis and discuss gene mutations and post-translational modification of them. Further research into the interactions between structural alterations and function of PMP22 and EMPs will help understand their normal physiological function and role in diseases and might contribute to developing novel therapeutic tools.

Loss of EMP1 promotes the metastasis of human bladder cancer cells by promoting migration and conferring resistance to ferroptosis through activation of PPAR gamma signaling

Metastasis, in which cancer cells detach from the original site and colonise other organs, is the primary cause of death induced by bladder cancer (BCa). Epithelial Membrane Protein 1 (EMP1) is dysregulated in many human cancers, and its clinical significance and biological function in diseases, including BCa, are largely unclear. Here, we demonstrated that EMP1 was downregulated in BCa cells. The deficiency of EMP1 promotes migration and confers resistance to ferroptosis/oxidative stress in BCa cells, favouring tumour cell metastasis. Mechanistically, we demonstrated that EMP1 deficiency enhanced tumour metastasis by increasing PPARG expression and promoting its activation, leading to upregulation of pFAK(Y397) and SLC7A11, which promoted cell migration and anti-ferroptotic cell death respectively. Moreover, we found EMP1-deficient sensitized cells to PPARG's ligand, which effect are metastatic phenotype promoted and could be mitigated by FABP4 knockdown. In conclusion, our study, for the first time, reveals that EMP1 deficiency promotes BCa cell migration and confers resistance to ferroptosis/oxidative stress, thus promoting metastasis of BCa via PPARG. These results revealed a novel role of EMP1-mediated PPARG in bladder cancer metastasis.

Epithelial Membrane Protein 1 Promotes Sensitivity to RSL3-Induced Ferroptosis and Intensifies Gefitinib Resistance in Head and Neck Cancer

Epithelial membrane protein (EMP1), a member of the peripheral myelin protein (PMP22) family, is involved in the development of various human malignancies. However, the expression level of EMP1 and its functional role in head and neck squamous cell carcinoma (HNSCC) remain unclear to date. Ferroptosis, a newly characterized form of regulated cell death, plays an essential role in tumorigenesis. In this study, we aimed to investigate the expression levels of EMP1 in HNSCC and normal tissues, as well as to identify the function of EMP1 in regulating ferroptosis during the progression of HNSCC. To further explore the biological function of EMP1 in vitro, transient transfection was used to overexpress EMP1 in the HNSCC cell lines Hep2 and Detroit562. Functionally, our results indicated that EMP1 overexpression could not affect the initiation of ferroptosis directly but reinforced RSL3-induced ferroptosis on HNSCC cells. Furthermore, mechanical study indicated that EMP1 mediated the ferroptosis via cell density-regulated Hippo-TAZ pathway and regulated the expression of Rac1 and NOX1. In addition, our study demonstrated that EMP1 overexpression could promote gefitinib resistance by targeting the MAPK pathway. In summary, our findings indicate that EMP1 may act as an oncogene and serve as a therapeutic target against malignant progression of HNSCC.

The Effects of Lentivirus-Mediated Gene Silencing of RARβ on the Stemness Capability of Non-Small Cell Lung Cancer

Retinoic acid receptor beta is a nuclear receptor protein that binds to retinoic acid (RA) to mediate cellular signalling in embryogenic morphogenesis, cell growth, and differentiation. However, the function of RARβ in cancer stem cells (CSCs) has yet to be determined. This study aimed to understand the role of RARβ in regulating cell growth and differentiation of lung cancer stem cells. Based on the clonogenic assay, spheroid assay, mRNA levels of stem cell transcription factors, and cell cycle being arrested at the G0/G1 phase, the suppression of RARβ resulted in significant inhibition of A549 parental cell growth. This finding was contradictory to the results seen in CSCs, where RARβ inhibition enhanced the cell growth of putative and non-putative CSCs. These results suggest that RARβ suppression may act as an essential regulator in A549 parental cells, but not in the CSCs population. The findings in this study demonstrated that the loss of RARβ promotes tumorigenicity in CSCs. Microarray analysis revealed that various cancer pathways were significantly activated following the suppression of RARβ. The changes seen might compensate for the loss of RARβ function, CSCs population's aggressiveness, which led to the CSCs population's aggressiveness. Thus, understanding the role of RARβ in regulating the stemness of CSCs may lead to targeted therapy for lung CSCs.

Epithelial Membrane Protein 2 Suppresses Non-Small Cell Lung Cancer Cell Growth by Inhibition of MAPK Pathway

Epithelial membrane proteins (EMP1-3) are involved in epithelial differentiation and carcinogenesis. Dysregulated expression of EMP2 was observed in various cancers, but its role in human lung cancer is not yet clarified. In this study, we analyzed the expression of EMP1-3 and investigated the biological function of EMP2 in non-small cell lung cancer (NSCLC). The results showed that lower expression of EMP1 was significantly correlated with tumor size in primary lung tumors (p = 0.004). Overexpression of EMP2 suppressed tumor cell growth, migration, and invasion, resulting in a G1 cell cycle arrest, with knockdown of EMP2 leading to enhanced cell migration, related to MAPK pathway alterations and disruption of cell cycle regulatory genes. Exosomes isolated from transfected cells were taken up by tumor cells, carrying EMP2-downregulated microRNAs (miRNAs) which participated in regulation of the tumor microenvironment. Our data suggest that decreased EMP1 expression is significantly related to increased tumor size in NSCLC. EMP2 suppresses NSCLC cell growth mainly by inhibiting the MAPK pathway. EMP2 might further affect the tumor microenvironment by regulating tumor microenvironment-associated miRNAs.

MicroRNA-95-3p serves as a contributor to cisplatin resistance in human gastric cancer cells by targeting EMP1/PI3K/AKT signaling

MicroRNAs (miRNAs) are thought to be involved in the development of cisplatin (DDP) resistance in gastric cancer (GC). Using RNA sequencing analysis (RNA-seq), we found that miR-95-3p is associated with DDP resistance in GC. We discovered that miR-95-3p is highly expressed in DDP-resistant GC tissues and cell lines (SGC7901/DDP and AGS/DDP). Furthermore, results from the BrdU and MTT assays indicated that miR-95-3p promotes GC cell proliferation. Additionally, data from transwell chamber assay, wound healing test and in vivo experiments illustrated that miR-95-3p can effectively promote invasion, migration and tumorigenic capacity, respectively, of DDP-resistant GC cells. Subsequently, results from dual luciferase assay and qRT-PCR collectively indicated that EMP1 is a target of miR-95-3p with inhibitory function through suppression of the EMT process and drug-resistance proteins. Furthermore, PI3K/AKT was identified as a downstream pathway of miR-95-3p, which promotes DDP resistance in GC. In summary, miR-95-3p helped develop DDP-resistance through down-regulation of EMP1 and increasing phosphorylation of the PI3K/Akt pathway in GC.

Prognostic Relevance of Expression of EMP1, CASP1, and NLRP3 Genes in Pediatric B-Lineage Acute Lymphoblastic Leukemia

Glucocorticoid (GC), such as prednisolone, is an essential component of multidrug chemotherapy regimen for pediatric acute lymphoblastic leukemia (ALL). Resistance to GC in leukemia cells is associated with disease progression and poor prognosis. Despite the extensive use of GC for many years, molecular mechanisms underlying its resistance in ALL have not been fully uncovered. Recent studies have shown a potential role of EMP1, CASP1, and NLRP3 genes in prednisolone response. In this study on 148 pediatric B-ALL patients, we studied these three genes to assess their association with prednisolone response measured by day 8 blast count after 7 days of induction therapy with prednisolone. Intriguingly, ALL samples exhibited higher expression of EMP1 along with a low expression of CASP1 and NLRP3 compared to disease free normal bone marrow collected from patients with solid tumors. Among the three analyzed genes, only EMP1 was found to be overexpressed in prednisolone poor responders (p=0.015). Further, a comparison of gene expression between cytogenetic subtypes revealed higher expression of EMP1 in BCR-ABL subtype. Expression of EMP1 in multiple gene expression datasets was used for gene set enrichment analysis, which revealed TNF-α, IL-2-STAT5 signaling, inflammatory responses and hypoxia as the major positively associated pathways and E2F targets as negatively associated pathways. Interestingly, the clinical remission rate was higher in CASP1 high patients (p=0.048). In univariate survival analysis, higher EMP1 expression was associated with poor prognostic measures while higher expression of NLRP3 and CASP1 was associated with better prognostic measures in our data. Further, multivariate analysis revealed an independent association of high CASP1 and NLRP3 with a better prognosis. This study strengthens the available evidence that mRNA expression of EMP1, CASP1, and NLRP3 may serve as potential biomarkers for risk stratification of pediatric B-ALL patients.

Markers of Angiogenesis, Lymphangiogenesis, and Epithelial-Mesenchymal Transition (Plasticity) in CIN and Early Invasive Carcinoma of the Cervix: Exploring Putative Molecular Mechanisms Involved in Early Tumor Invasion

The establishment of a proangiogenic phenotype and epithelial-to-mesenchymal transition (EMT) are considered as critical events that promote the induction of invasive growth in epithelial tumors, and stimulation of lymphangiogenesis is believed to confer the capacity for early dissemination to cancer cells. Recent research has revealed substantial interdependence between these processes at the molecular level as they rely on common signaling networks. Of great interest are the molecular mechanisms of (lymph-)angiogenesis and EMT associated with the earliest stages of transition from intraepithelial development to invasive growth, as they could provide the source of potentially valuable tools for targeting tumor metastasis. However, in the case of early-stage cervical cancer, the players of (lymph-)angiogenesis and EMT processes still remain substantially uncharacterized. In this study, we used RNA sequencing to compare transcriptomes of HPV(+) preinvasive neoplastic lesions and early-stage invasive carcinoma of the cervix and to identify (lymph-)angiogenesis- and EMT-related genes and pathways that may underlie early acquisition of invasive phenotype and metastatic properties by cervical cancer cells. Second, we applied flow cytometric analysis to evaluate the expression of three key lymphangiogenesis/EMT markers (VEGFR3, MET, and SLUG) in epithelial cells derived from enzymatically treated tissue specimens. Overall, among 201 differentially expressed genes, a considerable number of (lymph-)angiogenesis and EMT regulatory factors were identified, including genes encoding cytokines, growth factor receptors, transcription factors, and adhesion molecules. Pathway analysis confirmed enrichment for angiogenesis, epithelial differentiation, and cell guidance pathways at transition from intraepithelial neoplasia to invasive carcinoma and suggested immune-regulatory/inflammatory pathways to be implicated in initiation of invasive growth of cervical cancer. Flow cytometry showed cell phenotype-specific expression pattern for VEGFR3, MET, and SLUG and revealed correlation with the amount of tumor-infiltrating lymphocytes at the early stages of cervical cancer progression. Taken together, these results extend our understanding of driving forces of angiogenesis and metastasis in HPV-associated cervical cancer and may be useful for developing new treatments.

Expression of EMP1, EMP2, and EMP3 in breast phyllodes tumors

Purpose

Phyllodes tumors (PTs) are biphasic tumors accounting for 0.3–1.5% of all breast tumors. Epithelial membrane proteins (EMPs) have been reported in various malignant tumors but their expression in PTs is unclear. In this study, we aimed to evaluate the expression of EMP1, EMP2, and EMP3 in breast phyllodes tumors (PTs), and to investigate their clinical implications.

Methods

In total, 185 PTs were used for constructing a tissue microarray. Immunohistochemical staining for EMP1, EMP2, and EMP3 was performed, and the results were analyzed along with the clinicopathologic parameters.

Results

In total, 185 PTs were included in this study, and comprised 138 benign, 32 borderline, and 15 malignant PTs. In malignant PTs, the epithelial component showed decreased expression of EMP1 (P = 0.027), EMP2 (P = 0.004), and EMP3 (P = 0.032), compared to the benign and borderline PTs. Conversely, stromal component of borderline and malignant PTs showed higher expression of EMP1 (P = 0.027), EMP2 (P = 0.004), and EMP3 (P = 0.032) compared to benign PTs. Expression of EMP1 and EMP3 correlated positively with stromal cellularity and cellular atypia (P < 0.001). In the univariate analysis, stromal EMP3 was associated with shorter disease-free survival (P < 0.001), and shorter overall survival (P = 0.034).

Conclusion

The expression of EMP1, EMP2, and EMP3 is decreased in the epithelial component and is increased in the stromal component of PT with higher histologic grade. Thus, stromal EMP3 expression may serve as an independent prognostic factor in PT.

Five genes as a novel signature for predicting the prognosis of patients with laryngeal cancer

In this study, we purpose to investigate a novel five-gene signature for predicting the prognosis of patients with laryngeal cancer. The laryngeal cancer datasets were obtained from The Cancer Genome Atlas (TCGA). Both univariate and multivariate Cox regression analysis was applied to screening for prognostic differential expressed genes (DEGs), and a novel gene signature was obtained. The performance of this Cox regression model was tested by receiver operating characteristic (ROC) curves and area under the curve (AUC). Further survival analysis for each of the five genes was carried out through the Kaplan-Meier curve and Log-rank test. Totally, 622 DEGs were screened from the TCGA datasets in this study. We construct a five-gene signature through Cox survival analysis. Patients were divided into low- and high-risk groups depending on the median risk score, and a significant difference of the 5-year overall survival was found between these two groups (P < .05). ROC curves verified that this five-gene signature had good performance to predict the prognosis of laryngeal cancer (AUC = 0.862, P < .05). In conclusion, the five-gene signature consist of EMP1, HOXB9, DPY19L2P1, MMP1, and KLHDC7B might be applied as an independent prognosis predictor of laryngeal cancer.

Expression and Role of Epithelial Membrane Proteins in Tumorigenesis of Hormone Receptor-Positive Breast Cancer

Purpose

Studies on the expression of epithelial membrane proteins (EMPs) in breast cancer have been rare and limited. In the present study, we aimed to evaluate the expression of EMP1, EMP2, and EMP3 in invasive ductal carcinoma (IDC) of the breast, and investigate their clinical implications.

Methods

In total, 418 IDC cases were collected, and specimens were used to construct a tissue microarray. Immunohistochemical staining of EMP1, EMP2, and EMP3 was performed and the results were analyzed in combination with the clinical data.

Results

EMP1 was expressed in > 90% of all IDC subtypes. A decreased expression of EMP2 and EMP3 was observed in triple-negative breast cancer. EMP3 expression was independently associated with human epidermal growth factor receptor 2 (HER2) positivity. HER2-negative cases exhibited a decreased EMP2 expression along with a higher histological grade and an increased proliferative index. No significant difference was found in the overall survival or disease-free survival based on the EMP expression. In HER2-negative breast cancer, EMP2 expression inversely correlated with the histological grade and proliferative index.

Conclusion

EMP2 may be involved in the early stage of tumor development in hormone-positive breast cancer.

EMP1 promotes the malignant progression of osteosarcoma through the IRX2/MMP9 axis

BACKGROUND

Previous studies have demonstrated that EMP1 is an oncogene. In this paper, we aim to uncover the role of EMP1 in stimulating the malignant progression of osteosarcoma (OS) by the IRX2/MMP9 axis.

METHODS

EMP1 levels in 49 OS tissues and adjacent ones were detected. Potential correlation between EMP1 level and clinical data of OS patients was determined. Migratory and invasive abilities in SaOS-2 and U2OS cells influenced by EMP1 were examined by Transwell and wound healing assay. The involvement of IRX2 in OS cell metastasis regulated by EMP1 was finally explored.

RESULTS

EMP1 was upregulated in OS tissues than those of normal ones. Higher rates of lymphatic metastasis and distant metastasis were found in OS patients expressing higher level of EMP1, who suffered a worse prognosis. Knockdown of EMP1 inhibited migratory and invasive abilities in OS cells. Protein levels of IRX2 and MMP9 were upregulated after overexpression of EMP1. Rescue experiments verified that IRX2 was involved in EMP1-regulated malignant progression of OS.

CONCLUSIONS

EMP1 is upregulated in OS tissues and closely linked to lymphatic metastasis and distant metastasis. It stimulates the malignant progression of OS through the IRX2/MMP9 axis.

High expression of EMP1 predicts a poor prognosis and correlates with immune infiltrates in bladder urothelial carcinoma

Epithelial membrane protein 1 (EMP1) is a key gene that regulates cell proliferation and metastatic capability in various types of cancer, and serves an important role in tumor-immune interactions. However, the association between EMP1 and clinical prognosis, as well as the presence of tumor-infiltrating lymphocytes in bladder urothelial carcinoma (BLCA) remains unclear. The present study aimed to explore the relationship between EMP1 expression and tumor immune cell infiltration in BLCA. In the present study, EMP1 expression in BLCA was analyzed using the Oncomine database, The Cancer Genome Atlas (TCGA) and the Tumor Immune Estimation Resource (TIMER). The effects of EMP1 on clinical prognosis were evaluated using the Kaplan-Meier plotter and Gene Expression Profiling Interactive Analysis. The correlations between EMP1, cancer immune infiltrates and lymphocyte abundance were determined using the TIMER and Tumor immune system interaction database. In addition, correlations between EMP1 expression and gene markers in immune infiltrates were analyzed using cBioportal. The results demonstrated that, compared with adjacent normal tissues, EMP1 was downregulated in BLCA tissues. High expression of EMP1 was significantly associated with poor overall survival (OS) in BLCA cases obtained from TCGA. Multivariate Cox analysis revealed that EMP1 was an independent predictor of OS in patients with BLCA. Gene set enrichment analysis revealed that EMP1 was associated with cancer-related pathways and was positively correlated with the levels of infiltrating CD8⁺ T cells, macrophages, neutrophils and dendritic cells in BLCA. Further analysis demonstrated that EMP1 was significantly associated with the enrichment of multiple types of lymphocyte. EMP1 expression exhibited a strong correlation with a range of immune markers in BLCA. In conclusion, the results of the present study demonstrated that EMP1 was associated with a poor prognosis in patients with BLCA, and that the levels of immune infiltration and multiple immunomarker groups were associated with EMP1 expression. These results suggested that EMP1 may be used as a predictive biomarker to determine the prognosis and immune infiltration in BLCA.

The Pivotal Roles of the Epithelial Membrane Protein Family in Cancer Invasiveness and Metastasis

The members of the family of epithelial membrane proteins (EMPs), EMP1, EMP2, and EMP3, possess four putative transmembrane domain structures and are composed of approximately 160 amino acid residues. EMPs are encoded by the growth arrest-specific 3 (GAS3)/peripheral myelin protein 22 kDa (PMP22) gene family. The GAS3/PMP22 family members play roles in cell migration, growth, and differentiation. Evidence indicates an association of these molecules with cancer progression and metastasis. Each EMP has pro- and anti-metastatic functions that are likely involved in the complex mechanisms of cancer progression. We have recently demonstrated that the upregulation of EMP1 expression facilitates cancer cell migration and invasion through the activation of a small GTPase, Rac1. The inoculation of prostate cancer cells overexpressing EMP1 into nude mice leads to metastasis to the lymph nodes and lungs, indicating that EMP1 contributes to metastasis. Pro-metastatic properties of EMP2 and EMP3 have also been proposed. Thus, targeting EMPs may provide new insights into their clinical utility. Here, we highlight the important aspects of EMPs in cancer biology, particularly invasiveness and metastasis, and describe recent therapeutic approaches.

p53, miR-34a and EMP1-Newly Identified Targets of TFF3 Signaling in Y79 Retinoblastoma Cells

Trefoil factor family peptide 3 (TFF3) is supposed to have tumor suppressive functions in retinoblastoma (RB), but the functional pathway is not completely understood. In the study presented, we investigated the downstream pathway of TFF3 signaling in Y79 RB cells. Results from pG13-luciferase reporter assays and western blot analyses indicate induced p53 activity with an upregulation of miR-34a after TFF3 overexpression. Expression levels of the predicted miR-34a target epithelial membrane protein 1 (EMP1) are reduced after TFF3 overexpression. As revealed by WST-1 assay, BrdU, and DAPI cell counts viability and proliferation of Y79 cells significantly decrease following EMP1 knockdown, while apoptosis levels significantly increase. Opposite effects on Y79 cells’ growth could be shown after EMP1 overexpression. Caspase assays showed that EMP1 induced apoptosis after overexpression is at least partially caspase-3/7 dependent. Colony formation and soft agarose assays, testing for anchorage independent growth, revealed that EMP1 overexpressing Y79 cells have a significantly higher ability to form colonies. In in ovo chicken chorioallantoic membrane (CAM) assays inoculated EMP1 overexpressing Y79 cells form significantly larger CAM tumors. Moreover, miR-34a overexpression increases sensitivity of Y79 cells towards RB chemotherapeutics, however, without involvement of EMP1. In summary, the TFF3 signaling pathway in Y79 RB cells involves the activation of p53 with downstream induction of miR-34a and subsequent inhibition of EMP1.

Epithelial membrane protein 1 promotes glioblastoma progression through the PI3K/AKT/mTOR signaling pathway

Glioblastoma multiforme (GBM) is the most malignant intracranial tumor. Although the affected patients are usually treated with surgery combined with radiotherapy and chemotherapy, the median survival time for GBM patients is still approximately 12–14 months. Identifying the key molecular mechanisms and targets of GBM development may therefore lead to the development of improved therapies for GBM patients. In the present study, the clinical significance and potential function of epithelial membrane protein 1 (EMP1) in malignant gliomas were investigated. Increased EMP1 expression was associated with increasing tumor grade (P<0.001) and worse prognosis in patients (P<0.001) based on TCGA, Rembrandt and CGGA databases for human gliomas. In vitro, gene silencing of EMP1 in U87MG and P3 GBM (primary glioma) cells significantly inhibited tumor proliferation and invasion. In addition, it was revealed that activation of the PI3K/AKT/mTOR signaling pathway is the driving force of EMP1-promoted glioma progression. Finally, it was demonstrated, using an intracranial GBM animal model, that EMP1 knockdown significantly inhibits tumor growth in vivo and increases overall survival in tumor-bearing animals. Our research provides new insights into the molecular mechanisms underlying EMP1 knockdown-mediated inhibition of GBM cell invasion and raises the possibility that targeting of EMP1 may represent a promising strategy for the treatment of GBM.

EMP1 regulates cell proliferation, migration, and stemness in gliomas through PI3K-AKT signaling and CD44

Glioblastoma multiforme (GBM) is an intracranial tumor; the feature is higher malignant and poorer prognosis. The search for therapeutic targets for gliomas has always been a focus of research in the field of neurology. The unusual expression of epithelial membrane protein 1 (EMP1) has been proved in most tumors. In our study, we determined the expression level of EMP1 expression in glioma tissues. There were higher levels of EMP1 in glioma tissues-particularly GBM tissues-than those in normal brain tissues. Then we discovered that silencing EMP1 inhibited glioma cell invasion and proliferation through inhibiting the PI3K-AKT signaling pathway. Subsequently, we investigated the function of EMP1 on glioma stem cells and found that it regulates the expression of CD44 in such cells to promote stemness. Taken together, the new strategies for the treatment of glioma may be provided by these finding, thereby improving the prognosis associated with it.

Epithelial membrane protein 1 promotes tumor metastasis by enhancing cell migration via copine-III and Rac1

Tumor metastasis is the most common cause of cancer death. Elucidation of the mechanism of tumor metastasis is therefore important in the development of novel, effective anti-cancer therapies to reduce cancer mortality. Interaction between cancer cells and surrounding stromal cells in the tumor microenvironment is a key factor in tumor metastasis. Using a co-culture assay system with human prostate cancer LNCaP cells and primary human prostate stromal cells, we identified epithelial membrane protein 1 (EMP1) as a gene with elevated expression in the cancer cells. The orthotopic injection of LNCaP cells overexpressing EMP1 (EMP1-LNCaP cells) into the prostate of nude mice induced lymph node and lung metastases, while that of control LNCaP cells did not. EMP1-LNCaP cells had higher cell motility and Rac1 activity than control LNCaP cells. These results were also observed in other lines of cancer cells. We newly identified copine-III as an intracellular binding partner of EMP1. Knockdown of copine-III attenuated the increased cell motility and Rac1 activity in EMP1-LNCaP cells. Reduced cell motility and Rac1 activity following knockdown of copine-III in EMP1-LNCaP cells were recovered by re-expression of wild-type copine-III, but not of a copine-III mutant incapable of interacting with EMP1, suggesting the importance of the EMP1–copine-III interaction. Phosphorylated and activated Src and a Rac guanine nucleotide exchange factor Vav2 were found to be involved in the EMP1-induced enhancement of cell motility and Rac1 activation. Moreover, EMP1 was highly expressed in prostate cancer samples obtained from patients with higher Gleason score. These results demonstrate that upregulation of EMP1 significantly increases cancer cell migration that leads to tumor metastasis, suggesting that EMP1 may play an essential role as a positive regulator of tumor metastasis.

The Prognostic Value of Epithelial Membrane Protein 1 (EMP-1) in Patients with Laryngeal Carcinoma

Background

In the present study, we aimed to investigate the prognostic value of epithelial membrane protein 1 (EMP-1) gene in patients diagnosed with laryngeal carcinoma (LC).

Material/Methods

Patients who were pathologically diagnosed with LC were enrolled in the present study. The expression levels of EMP-1 in tumor tissues and corresponding normal tissues collected from the LC patients were detected by semi-reverse transcriptase polymerase chain reaction (semi-RT-PCR). Chi-square analysis was used to evaluate the relationship between EMP-1 expression level and clinical characteristics. Survival analysis for the study population was analyzed by Kaplan-Meier method with log rank test. Additionally, Cox regression model was applied to evaluate the prognostic value of EMP-1 in LC patients.

Results

106 LC patients, including 55 men and 51 women, were enrolled in the present study. Semi-RT-PCR demonstrated that the expression level of EMP-1 was decreased in tumor tissues, compared with adjacent normal tissues (p<0.001). Moreover, the level was significantly associated with lymph node metastasis, histological grade, and clinical stage (p<0.05 for all). In addition, low levels of EMP-1 was significantly correlated with poor survival rate (log rank test, p=0.020). Cox regression analysis indicated that EMP-1 was an independent marker for LC prognosis (HR=2.755, 95% CI=1.123–6.760, p=0.027).

Conclusions

The abnormal expression of EMP-1 may be associated with progression of LC and the gene may act as a prognostic marker for LC.

EMP1, EMP 2, and EMP3 as novel therapeutic targets in human cancer

The epithelial membrane protein genes 1, 2, and 3 (EMP1, EMP2, and EMP3) belong to the peripheral myelin protein 22-kDa (PMP22) gene family, which consists of at least seven members: PMP22, EMP1, EMP2, EMP3, PERP, brain cell membrane protein 1, and MP20. This review addresses the structural and functional features of EMPs, detailing their tissue distribution and functions in the human body, their expression pattern in a variety of tumors, and highlighting the underlying mechanisms involved in carcinogenesis. The implications in cancer biology, patient prognosis prediction, and potential application in disease therapy are discussed. For example, EMP1 was reported to be a biomarker of gefitinib resistance in lung cancer and contributes to prednisolone resistance in acute lymphoblastic leukemia patients. EMP2 functions as an oncogene in human endometrial and ovarian cancers; however, characteristics of EMP2 in urothelial cancer fulfill the criteria of a suppressor gene. Of particular interest, EMP3 overexpression in breast cancer is significantly related to strong HER-2 expression. Co-expression of HER-2 and EMP3 is the most important indicator of progression-free and metastasis-free survival for patients with urothelial carcinoma of the upper urinary tract. Altogether, discovery of pharmacological inhibitors and/or regulators of EMP protein activity could open novel strategies for enhanced therapy against EMP-mediated human diseases.

The expression and function of epithelial membrane protein 1 in laryngeal carcinoma

In this study, we compared the expression of epithelial membrane protein 1 (EMP1) on the steady-state mRNA level (by quantitative real-time PCR) and on the protein level (by western immunoblot and immunohistochemistry) in 51 pairs of laryngeal carcinoma tissues and matched cancer-free peritumor tissues, and we analyzed the correlation between EMP1 expression and different clinicopathological factors. Furthermore, we ectopically expressed EMP1 in human laryngeal carcinoma Hep-2 cells and examined the effects on cell viability, apoptosis, colonogenicity, and motility, by MTT assay, flow cytometry, colony formation assay and Transwell migration assay, respectively. EMP1 expression (on both the mRNA and protein levels) was significantly lower in the cancer tissues than in matched peritumor tissues (P<0.05). In laryngeal cancers, the level of EMP1 protein was correlated with histological grade (P<0.05), but not with age, gender, clinical stage, cancer subtype or lymph node metastasis (P>0.05). Functionally, ectopic expression of EMP1 in Hep-2 cells significantly reduced cell viability, colony formation, and migration, but enhanced apoptosis. Therefore, EMP1 is a tumor suppressor in laryngeal carcinoma. Boosting EMP1 expression in laryngeal carcinoma initiates multiple anticancer phenotypes and thus presents a promising therapeutic strategy for laryngeal cancer.

[Construction of epithelial membrane protein 1 eukaryotic expression vector and its influence on migration and invasion of human oral tongue squamous carcinoma cells]

OBJECTIVE

This study aimed to construct a eukaryotic expression vector pEGFP-N1-EMP1 of epithelial mem-brane protein 1 (EMP1) and investigate its influence on migration and invasion of human oral tongue squamous carcinoma cells.

METHODS

The human EMP1 gene was amplified by reverse transcription polymerase chain reaction and then ligated into the pEGFP-N1 vector by double restriction endonuclease digestion to construct pEGFP-N1-EMP1 recombinant plasmid. After sequencing identification, pEGFP-N1-EMP1 recombinant plasmid and pEGFP-N1 plasmid were transfected into human oral tongue squamous carcinoma Tb3.1 cell line. The expression of green fluorescent protein in cells was observed after transfection using an inverted fluorescence microscope. The overexpression of EMP1 mRNA was identified at 24, 48, and 72 h after transfection by real-time fluorescence quantitative polymerase chain reaction. The effect of EMP1 overexpression on migration and invasion of Tb3.1 cells was detected by Transwell assay.

RESULTS

The full-length EMP1 gene sequence was successfully obtained. Sequence analysis showed that the EMP1 gene was inserted into the pEGFP-N1 vector correctly. Green fluorescence was observed in the transfected cells under fluorescence microscopy. The results of real-time fluorescence quantitative polymerase chain reaction indicated that the expression of EMP1 at 24 h after pEGFP-N1-EMP1 transfection was significantly higher than the other groups. Transwell assays indicated that overexpression of the EMP1 gene could significantly inhibit the migration and invasion ability of Tb3.1 cells.

CONCLUSIONS

The eukaryotic expression vector of EMP1 was successfully constructed, and EMP1 overexpression was confirmed to inhibit the migration and inva-sion of oral tongue squamous carcinoma cells in vitro. This study laid a foundation for further investigation on the influence of the EMP1 gene on the metastasis of oral tongue squamous carcinoma and its molecular mechanism.
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Upregulation of KLHDC4 Predicts a Poor Prognosis in Human Nasopharyngeal Carcinoma

Kelch proteins are implicated in the pathogenesis of many human diseases, including cancer. Nasopharyngeal carcinoma (NPC) is a rare malignancy in most countries, but prevalent in southern China and certain areas of Southeast Asia. In this study, we identified Kelch Domain Containing 4 (KLHDC4), an orphan member of the kelch repeat superfamily, as a prognosis marker for NPC. We examined the expression of KLHDC4 in 168 NPC cases by immunohistochemical staining and found a substantially higher level of KLHDC4 in NPC biopsies compared to adjacent normal nasopharyngeal mucosa. KLHDC4 expression was significantly related to the T classification (P <0.05), N classification (P <0.05) and total staging (P <0.01) in NPC, and patients with higher KLHDC4 expression had poorer overall (P <0.01) and metastasis-free survival (P <0.05) rates. Knockout (KO) of KLHDC4 via CRISPR/Cas9-mediated gene editing in NPC cell line dramatically inhibited cell proliferation, colony formation in soft agar and tumor formation in nude mice. In addition, cell migration and invasion were also impaired by KLHDC4 depletion as revealed by wound healing and Transwell assay. Mechanically, loss of KLHDC4 markedly induced spontaneous apoptosis in NPC cells, as evidenced by increased levels of cleaved caspase-3 and cleaved PARP. Consistently, KLHDC4 knockout cell-derived xenografts also showed elevated cleaved caspase-3 and PARP but reduced Ki-67 staining. In conclusion, our results suggest that KLHDC4 promotes NPC oncogenesis by suppressing cellular apoptosis. Thus, KLHDC4 may serve as a prognosis biomarker and a potential therapeutic target for NPC.

Epithelial membrane protein 1 expression in ovarian serous tumors

The present study aimed to analyze the clinical significance of epithelial membrane protein 1 (EMP1) expression in ovarian serous tumors. A total of 84 cases of ovarian serous tumor (50 patients with malignant ovarian serous tumors and 34 patients with borderline and benign serous tumors) were retrospectively analyzed. Differences in the expression levels of EMP1 between the malignant and non-malignant tumor groups were evaluated by immunohistochemical staining. In addition, the association between EMP1 expression and prognostic factors in malignant ovarian serous tumors was investigated. The expression levels of EMP1 were significantly reduced in all the 50 malignant ovarian serous tumors, compared with the 34 non-malignant ovarian serous tumors (P<0.000). Reduced expression of EMP1 was correlated with high grade (P=0.009) and stage (P<0.000) of malignant tumors. EMP1 expression was not observed to be correlated with any other investigated parameters, including surgery, type of operation and chemotherapy response (P>0.005). These results indicated that EMP1 may have a significant role as a negative regulator in ovarian serous tumors, and reduced EMP1 expression in serous tumors may be associated with increased disease severity.

MicroRNA-31 Promotes Skin Wound Healing by Enhancing Keratinocyte Proliferation and Migration

Wound healing is a basic biological process restoring the integrity of the skin. The role of microRNAs during this process remains largely unexplored. By using an in vivo human skin wound healing model, we show here that the expression of miR-31 is gradually upregulated in wound edge keratinocytes in the inflammatory (1 day after injury) through the proliferative phase (7 days after injury) in comparison with intact skin. In human primary keratinocytes, overexpression of miR-31 promoted cell proliferation and migration, whereas inhibition of miR-31 had the opposite effects. Moreover, we identified epithelial membrane protein 1 (EMP-1) as a direct target of miR-31 in keratinocytes. The expression of EMP-1 in the skin was negatively correlated with the level of miR-31 during wound healing. Silencing of EMP-1 mimicked the effects of overexpression of miR-31 on keratinocyte proliferation and migration, indicating that EMP-1 is a critical target mediating the functions of miR-31 in keratinocytes. Finally, we demonstrated that transforming growth factor-β2, which is highly expressed in skin wounds, upregulated miR-31 expression in keratinocytes. Collectively, we identify miR-31 as a key regulator for promoting keratinocyte proliferation and migration during wound healing.

SOS1 and Ras regulate epithelial tight junction formation in the human airway through EMP1

The human airway is lined with respiratory epithelial cells, which create a critical barrier through the formation of apical tight junctions. To investigate the molecular mechanisms underlying this process, an RNAi screen for guanine nucleotide exchange factors (GEFs) was performed in human bronchial epithelial cells (16HBE). We report that SOS1, acting through the Ras/MEK/ERK pathway, is essential for tight junction formation. Global microarray analysis identifies epithelial membrane protein 1 (EMP1), an integral tetraspan membrane protein, as a major transcriptional target. EMP1 is indispensable for tight junction formation and function in 16HBE cells and in a human airway basal progenitor-like cell line (BCi-NS1.1). Furthermore, EMP1 is significantly downregulated in human lung cancers. Together, these data identify important roles for SOS1/Ras and EMP1 in tight junction assembly during airway morphogenesis.