Epithelial membrane protein 3 is frequently shown as promoter methylation and functions as a tumor suppressor gene in non-small cell lung cancer

EMP3 as a prognostic biomarker correlates with EMT in GBM

BACKGROUND

Glioblastoma (GBM) is the most aggressive malignant central nervous system tumor with a poor prognosis.The malignant transformation of glioma cells via epithelial-mesenchymal transition (EMT) has been observed as a main obstacle for glioblastoma treatment. Epithelial membrane protein 3 (EMP3) is significantly associated with the malignancy of GBM and the prognosis of patients. Therefore, exploring the possible mechanisms by which EMP3 promotes the growth of GBM has important implications for the treatment of GBM.

METHODS

We performed enrichment and correlation analysis in 5 single-cell RNA sequencing datasets. Differential expression of EMP3 in gliomas, Kaplan-Meier survival curves, diagnostic accuracy and prognostic prediction were analyzed by bioinformatics in the China Glioma Genome Atlas (CGGA) database and The Cancer Genome Atlas (TCGA) database. EMP3-silenced U87 and U251 cell lines were obtained by transient transfection with siRNA. The effect of EMP3 on glioblastoma proliferation was examined using the CCK-8 assay. Transwell migration assay and wound healing assay were used to assess the effect of EMP3 on glioblastoma migration. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were used to detect the mRNA and protein expression levels of EMT-related transcription factors and mesenchymal markers.

RESULTS

EMP3 is a EMT associated gene in multiple types of malignant cancer and in high-grade glioblastoma. EMP3 is enriched in high-grade gliomas and isocitrate dehydrogenase (IDH) wild-type gliomas.EMP3 can be used as a specific biomarker for diagnosing glioma patients. It is also an independent prognostic factor for glioma patients' overall survival (OS). In addition, silencing EMP3 reduces the proliferation and migration of glioblastoma cells. Mechanistically, EMP3 enhances the malignant potential of tumor cells by promoting EMT.

CONCLUSION

EMP3 promotes the proliferation and migration of GBM cells, and the mechanism may be related to EMP3 promoting the EMT process in GBM; EMP3 may be an independent prognostic factor in GBM.

EMP3 as a key downstream target of miR-663a regulation interferes with MAPK/ERK signaling pathway to inhibit gallbladder cancer progression

Gallbladder carcinoma (GBC) is the most common malignancy of the biliary tract, and its molecular pathogenesis remains unclear. Here we explore the functional roles of epithelial membrane protein 3 (EMP3) in GBC progression, which is aberrantly expressed in various types of cancers. The results showed that the expression level of EMP3 was reduced in human GBC tissues compared with non-malignant tissues. Further, the low expression of EMP3 was associated with the poor prognosis of GBC patients by Kaplan-Meier analysis. The ectopic expression of EMP3 inhibited GBC cell proliferation, migration and invasion in vitro and in vivo. Conversely, the depletion of EMP3 promoted GBC cell growth and metastasis. In addition, we found that EMP3 was a target gene of miR-663a, and the downregulation of EMP3 in GBC was attributed to the overexpression of miR-663a. MiR-663a was also shown to be a tumor-promoting factor mediating GBC development. In this study, we demonstrate that downregulation of EMP3 activates MAPK/ERK signaling, which regulates GBC progression. These data reveal the mechanism by which EMP3 inhibits the progression of GBC, suggesting that the miR-663a/EMP3/MAPK/ERK axis may be a new therapeutic target for GBC treatment.

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.

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.

Establishment of a nomogram with EMP3 for predicting clinical outcomes in patients with glioma: A bi-center study

Aim

To demonstrate the clinical value of epithelial membrane protein 3 (EMP3) with bioinformatic analysis and clinical data, and then to establish a practical nomogram predictive model with bicenter validation.

Methods

The data from CGGA and TCGA database were used to analyze the expression of EMP3 and its correlation with clinical prognosis. Then, we analyzed EMP3 expression in samples from 179 glioma patients from 2013 to 2017. Univariate and multivariate cox regression were used to predict the prognosis with multiple factors. Finally, a nomogram to predict poor outcomes was formulated. The accuracy and discrimination of nomograms were determined with ROC curve and calibration curve in training and validation cohorts.

Results

EMP3 was significantly higher in higher‐grade glioma and predicted poor prognosis. In multivariate analysis, high expression of EMP3 (HR = 2.842, 95% CI 1.984–4.071), WHO grade (HR = 1.991, 95% CI 1.235–3.212), and IDH1 mutant (HR = 0.503, 95% CI 0.344–0.737) were included. The nomogram was constructed based on the above features, which represented great predictive value in clinical outcomes.

Conclusion

This study demonstrated EMP3 as a novel predictor for clinical progression and clinical outcomes in glioma. Moreover, the nomogram with EMP3 expression represented a practical approach to provide individualized risk assessment for glioma patients.

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.

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.

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.

Long Noncoding RNAs and Messenger RNAs Expression Profiles Potentially Regulated by ZBTB7A in Nasopharyngeal Carcinoma

Our previous studies showed that ZBTB7A played an important role in promoting nasopharyngeal carcinoma (NPC) progression. However, molecular mechanisms of different levels of ZBTB7A are still unclear. It is necessary to search molecular markers which are closely connected with ZBTB7A. We selected NPC sublines CNE2 with stably transfecting empty plasmid (negative control, NC) and short hair RNA (shRNA) plasmid targeting ZBTB7A as research objectives. Microarray was used to screen differentially expressed long noncoding RNAs (lncRNAs) and messenger RNAs (mRNAs) via shRNA-CNE2 versus NC-CNE2. Quantitative PCR (qPCR) was used to validate lncRNAs and mRNAs from the sublines, chronic rhinitis, and NPC tissues. Bioinformatics was used to analyze regulatory pathways which were connected with ZBTB7A. The 1501 lncRNAs (long noncoding RNAs) and 1275 differentially expressed mRNAs were upregulated or downregulated over 2-fold. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the upregulated or downregulated carbohydrate and lipid metabolisms probably involved in carcinogenicity of shRNA-CNE2 (P-value cut-off was 0.05). In order to find the molecular mechanisms of ZBTB7A, we validated 12 differentially expressed lncRNAs and their nearby mRNAs by qPCR. Most of the differentially expressed mRNAs are closely connected with carbohydrate and lipid metabolisms in multiply cancers. Furthermore, part of them were validated in NPC and rhinitis tissues by qPCR. As a result, NR_047538, ENST00000442852, and fatty acid synthase (FASN) were closely associated with NPC. ZBTB7A had a positive association with NR_047538 and negative associations with ENST00000442852 and FASN. The results probably provide novel candidate biomarkers for NPC progression with different levels of ZBTB7A.

Characterization of the epithelial membrane protein 3 interaction network reveals a potential functional link to mitogenic signal transduction regulation

Epithelial Membrane Protein 3 (EMP3), a 4-transmembrane glycoprotein, first gained attention as a putative tumor suppressor. Accumulating evidence, however, points to a more tumor promotive function of EMP3. The biological function of EMP3 remains largely unclear. To elucidate more of EMP3's interaction network, we performed a Yeast-Two-Hybrid (Y2H) screening, followed by validation of candidate interactors by Biomolecular Fluorescence Complementation (BiFC) and Proximity Ligation Assay (PLA). Furthermore, we generated stable EMP3 knockdown cell lines and measured cell proliferation, migration and sensitivity to apoptosis induction as well as the expression and activation levels of important signal pathway components. The Y2H screening yielded 10 novel interactions of EMP3, eight of which could also be detected by BiFC and PLA interaction assays. All newly discovered interaction partners are involved in signaling or trafficking regulation. Most notably, FLOT1 and HTATIP2 have well described roles in the regulation of EGFR signaling. In addition, knockdown of EMP3 resulted in reduced levels of p-AKT, p-ERK and p-EGFR, attenuated cell proliferation and migration and sensitized cells to apoptosis induction by TRAIL and Staurosporine. Based on these observations we hypothesize that EMP3 might be involved in the regulation of receptor-tyrosine-kinase mediated mitogenic signaling.

RETRACTED: EMP3, which is regulated by miR-663a, suppresses gallbladder cancer progression via interference with the MAPK/ERK pathway

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor. Following the publication of the above article, the Editor was notified that images were duplicated in the migration and invasion experiments in Figures 3A, 6C, 7D and 8D: https://pubpeer.com/publications/76E82FD26E33503D7CCAC01C324AFA. The Editor has taken the decision to retract the paper as it is no longer acceptable in its current form

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.

Inhibition of CD9 expression reduces the metastatic capacity of human hepatocellular carcinoma cell line MHCC97-H

Metastasis is a characteristic of malignant tumors and may be a fatal clinical factor for many patients with cancer. Hepatocellular carcinoma (HCC) cells are highly metastatic; the mechanism of metastasis is complicated and may be influenced by a number of factors. Membrane proteins may block receptors or inhibit important enzymes, thus inhibiting tumor progression, and may be potential therapeutic targets for tumor prognosis and treatment. The present study aimed to use proteomics to analyze the dynamic changes of membrane proteins in HCC cells, to improve our understanding of membrane protein functions and to clarify the important components of the mechanisms of HCC metastasis. The present study used the highly metastatic MHCC97-H and the lowly metastatic MHCC97-L HCC cell lines, and the isobaric tags for relative and absolute quantitation (iTRAQ) approach was used for high-throughput screening of metastasis-related membrane proteins. A total of 22 membrane proteins were identified as differentially expressed between the MHCC97-H and MHCC97-L cell lines; these results were verified by reverse transcription-quantitative polymerase chain reaction and western blotting. A number of the identified proteins were revealed to be related to tumor metastasis, including the tetraspan in transmembrane protein CD9. CD9 was demonstrated to be highly expressed in MHCC97-H cells compared with MHCC97-L cells. The functional role of CD9 was characterized by inhibiting its expression using a small interfering RNAs, which demonstrated that reduced CD9 expression inhibited cell migration and metastasis, as determined by wound-healing and invasion assays. Results from the present study demonstrated that CD9 was highly expressed in the highly metastatic HCC cells and promoted HCC cell migration. This protein may be a novel target for regulating the invasive phenotype in HCC.

High EMP3 expression might independently predict poor overall survival in glioblastoma and its expression is related to DNA methylation

In this study, we analyzed the prognostic value of epithelial membrane protein 3 (EMP3) in terms of overall survival (OS) in glioblastoma multiforme (GBM) and the association between its expression and DNA methylation.Bioinformatic analysis was performed by using data from the Cancer Genome Atlas (TCGA) database.EMP3 expression was markedly higher in GBM tissues than in normal brain tissues. High EMP3 expression was associated with significantly worse OS in patients with GBM. Univariate and multivariate analysis showed that EMP3 expression was an independent prognostic factor of poor OS no matter converting its expression into categorical variables (Hazard Ratio [HR] = 1.359, 95%CI: 1.118-1.652, P = .002) or setting it as a continuous variable (HR = 1.178, 95%CI: 1.101-1.260, P < .001). Among different subtypes of GBM, proneural subtype had the lowest EMP3 expression. The lowest EMP3 expression was observed in cluster 5 DNA methylation, which all belong to G-CIMP phenotype. Regression analysis confirmed a moderate negative correlation between EMP3 expression and its DNA methylation (Pearson's r = -0.61).Based on these findings, we infer that high EMP3 expression might be an independent indicator of unfavorable OS in GBM. EMP3 expression might be repressed by DNA methylation.

Epithelial membrane protein 3 regulates TGF-β signaling activation in CD44-high glioblastoma

Although epithelial membrane protein 3 (EMP3) has been implicated as a candidate tumor suppressor gene for low grade glioma, its biological function in glioblastoma multiforme (GBM) still remains poorly understood. Herein, we showed that EMP3 was highly expressed in CD44-high primary GBMs. Depletion of EMP3 expression suppressed cell proliferation, impaired in vitro tumorigenic potential and induced apoptosis in CD44-high GBM cell lines. We also identified TGF-β/Smad2/3 signaling pathway as a potential target of EMP3. EMP3 interacts with TGF-βreceptor type 2 (TGFBR2) upon TGF-βstimulation in GBM cells. Consequently, the EMP3-TGFBR2 interaction regulates TGF-β/Smad2/3 signaling activation and positively impacts on TGF-βstimulated gene expression and cell proliferation in vitro and in vivo. Highly correlated protein expression of EMP3 and TGF-β/Smad2/3 signaling pathway components was also observed in GBM specimens, confirming the clinical relevancy of activated EMP3/TGF-β/Smad2/3 signaling in GBM. In conclusion, our findings revealed that EMP3 might be a potential target for CD44-high GBMs and highlight the essential functions of EMP3 in TGF-β/Smad2/3 signaling activation and tumor progression.

EMP3 is induced by TWIST1/2 and regulates epithelial-to-mesenchymal transition of gastric cancer cells

In this study, we aimed to explore new downstream effectors of TWIST1/2 in inducing epithelial-to-mesenchymal transition in gastric cancer. Bioinformatic data mining was performed using data in The Cancer Genome Atlas Stomach Adenocarcinoma. Survival curves were generated using Kaplan-Meier plotter. Gastric cancer cell lines (AGS and SGC-7901) were used as in vitro cell model to investigate the regulative effect of TWIST1/2 on epithelial membrane protein 3 expression and the progression of epithelial-to-mesenchymal transition. Results showed that TWIST1 and TWIST2 are usually co-upregulated in patients with primary gastric cancer. High TWIST1 expression is associated with worse overall survival (hazard ratio = 1.26; 95% confidence interval = 1.06-1.49; p = 0.007) and also worse first progression-free survival (hazard ratio = 1.47; 95% confidence interval = 1.18-1.82; p < 0.0001). Similarly, high TWIST2 expression is associated with unfavorable overall survival (hazard ratio = 1.71; 95% confidence interval = 1.32-2.22; p < 0.0001) and progression-free survival (hazard ratio = 1.99; 95% confidence interval = 1.45-2.72; p < 0.0001). Epithelial membrane protein 3 is negatively correlated to CDH1 expression (Pearson's r = -0.46) but is positively correlated to VIM expression (Pearson's r = 0.83). Knockdown of epithelial membrane protein 3 significantly increased E-cadherin but significantly decreased Vimentin expression in AGS cells. Gastric cancer patients with metastasis have significantly higher epithelial membrane protein 3 expression than the cases without metastasis. In addition, high epithelial membrane protein 3 expression is associated with worse overall survival (hazard ratio = 2.59; 95% confidence interval = 2.06-3.26; p < 0.0001) and also worse progression-free survival (hazard ratio = 2.21; 95% confidence interval = 1.78-2.74; p < 0.0001). In conclusion, epithelial membrane protein 3 is a downstream effector of TWIST1/2 in inducing epithelial-to-mesenchymal transition in gastric cancer. Epithelial membrane protein 3 upregulation might be associated with gastric cancer metastasis and is a potential indicator of unfavorable overall survival and progression-free survival in gastric cancer patients.

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.

TNF-α inhibits the migration of oral squamous cancer cells mediated by miR-765-EMP3-p66Shc axis

Whereas TNF-α can facilitate the metastasis of oral squamous cancer cells (OSCC), whether it inhibits the metastasis is not clear so far. In this study, we demonstrated that high dose TNF-α at 100ng/mL could in vitro significantly inhibit the migration of two OSCC cell lines, CAL-27 and SCC-25. To explore the related mechanisms, we focused on the involvement of the microRNAs and found that TNF-α increased the expression of miR-765. The upregulation of miR-765 was attributed to the inhibition of the migration. We showed that miR-765 directly targeted EMP3 and suppressed its expression. We also found that the expression of EMP3 was much higher in human oral squamous cancer in compare with the surrounding normal tissue. Interestingly, p66Shc, a downstream molecule in the EMP3-related signaling pathway, was increased by TNF-α. We found that the overexpression of p66Shc could suppress the migration through the enhanced E-cadherin and ZO-1 signals. Either silencing the expression of EMP3 or enhancing the expression of miR-765 could upregulate the expression of p66Shc. Together, our results demonstrated that TNF-α inhibited the metastasis of oral squamous cancer cell through the miR-765-EMP3-p66Shc axis, which may provide new insights for the therapy of oral squamous cancer.

High expression of PINK1 promotes proliferation and chemoresistance of NSCLC

PTEN-induced putative kinase 1 (PINK1) was identified initially as a gene upregulated in cancer cells which regulates cellular processes of significance in cancer cell biology, including cell survival, stress resistance and the cell cycle. However, the expression and function of PINK1 in non-small cell lung cancer (NSCLC) has not been determined yet. We demonstrated high PINK1 expression in NSCLC tumor tissues and cell lines as assessed by western blot and immunohistochemistry (IHC) assays. In addition, IHC analysis revealed that PINK1 expression was associated with a more invasive tumor phenotype and poor prognosis. Furthermore, in vitro studies using upregulation and knockdown of PINK1 confirmed that PINK1 promoted cell proliferation of NSCLC, which might be through as the NF-κB pathway. Moreover, we also demonstrated that downregulation of PINK1 enhanced cisplatin (CDDP)-induced NSCLC cell apoptosis. Together, our findings indicate that PINK1 plays a significant role in NSCLC progression and chemoresistance, and highlights its potential role as a target in future anticancer therapies.

Targeting EMP3 suppresses proliferation and invasion of hepatocellular carcinoma cells through inactivation of PI3K/Akt pathway

Epithelial membrane protein-3 (EMP3), a typical member of the epithelial membrane protein (EMP) family, is epigenetically silenced in some cancer types, and has been proposed to be a tumor suppressor gene. However, its effects on tumor suppression are controversial and its roles in development and malignancy of hepatocellular carcinoma (HCC) remain unclear. In the present study, we found that EMP3 was highly expressed in the tumorous tissues comparing to the matched normal tissues, and negatively correlated with differentiated degree of HCC patients. Knockdown of EMP3 significantly reduced cell proliferation, arrested cell cycle at G1 phase, and inhibited the motility and invasiveness in accordance with the decreased expression and activity of urokinase plasminogen activator (uPA) and matrix metalloproteinase 9 (MMP-9) in HCC cells. The in vivo tumor growth of HCC was effectively suppressed by knockdown of EMP3 in a xenograft mouse model. The EMP3 knockdown-reduced cell proliferation and invasion were attenuated by inhibition of phosphatidylinositol 3-kinase (PI3K) or knockdown of Akt, and rescued by overexpression of Akt in HCC cells. Clinical positive correlations of EMP3 with p85 regulatory subunit of PI3K, p-Akt, uPA, as well as MMP-9 were observed in the tissue sections from HCC patients. Here, we elucidated the tumor progressive effects of EMP3 through PI3K/Akt pathway and uPA/MMP-9 cascade in HCC cells. The findings provided a new insight into EMP3, which might be a potential molecular target for diagnosis and treatment of HCC.

Impact of IGF-1, IGF-1R, and IGFBP-3 promoter methylation on the risk and prognosis of esophageal carcinoma

The aim of this study is to investigate IGF-1, IGF-1R, and IGFBP-3 methylations in esophageal carcinoma (EC) patients and their relationship with the development and prognosis of EC. This study population consisted of 264 patients (case group) whom EC radical resection was performed and 283 healthy individuals (control group). Methylation-specific PCR (MSP) detected the methylation status of IGF-1, IGF-1R, and IGFBP-3 in the peripheral blood in both groups. The expressions of IGF-1, IGF-1R, and IGFBP-3 in EC and adjacent normal tissues were detected by immunohistochemistry (IHC). The methylation rates of IGF-1, IGF-1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 in the case group were higher than those in the control group (all P < 0.05). Additionally, there were statistical significances for the methylation rates of IGF-1, IGF-1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 IGF-1 among patients of different clinicopathological features (all P < 0.05). The positive expression rates of IGF-1 and IGF-1R in EC were significantly higher than those in adjacent normal tissues (both P < 0.001), and the rate of IGFBP-3 in EC was significantly lower than that in adjacent normal tissues (P < 0.05). Correlation analysis showed that IGF-1 and IGF1R gene promoter methylation was positively correlated with the positive expressions of IGF-1 (r = 0.139, P = 0.024) and IGF-1R (r = 0.135, P = 0.028), while the IGFBP3 methylation was negatively correlated with the positive expression of IGFBP3 (r = -0.133, P = 0.031). The positive expressions of IGF-1, IGF-1R, and IGFBP-3 were related to different clinicopathological features (all P < 0.05). Cox multivariate analysis results showed that methylation status of IGF-1, IGF-1R, and IGF-1 + IGF1R + IGFBP3 ; expressions of IGF-1 and IGF-1R protein; infiltration depth; and lymph node metastasis (LNM) were independent factors of EC prognosis. Our study demonstrated that methylation of IGF-1, IGF1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 was closely linked with the occurrence of EC and patients' clinicopathological features. Besides, the methylation status of the target genes and the expressions of IGF-1 and IGF-1R protein were independent factors of EC prognosis, which could provide a direction for the prognosis and treatment of EC.

Epithelial membrane protein 3 functions as an oncogene and is regulated by microRNA-765 in primary breast carcinoma

Epithelial membrane protein 3 (EMP3) is a transmembrane signaling molecule, which is important in the regulation of apoptosis, differentiation and invasion of cancer cells. However, the specific function and regulatory mechanism of EMP3 in primary breast carcinoma remain to be elucidated. In the present study, the mRNA and protein levels of EMP3 were observed to be upregulated in primary breast carcinoma tissues, compared with normal tissues. It was hypothesized that the overexpression of EMP3 was correlated with the downregulation of microRNA‑765 (miR‑765), an underexpressed miRNA in primary breast carcinoma tissues. Functional analysis demonstrated that EMP3 was regulated by miR‑765 through binding to its 3'untranslated region. In addition, the knockdown of EMP3 and miR‑765 had similar effects on the inhibition of proliferation and invasion in SK‑BR‑3 cells. These results provided novel insight into the regulatory mechanism of EMP3 in primary breast carcinoma.

Histamine-releasing factor/translationally controlled tumor protein plays a role in induced cell adhesion, apoptosis resistance and chemoresistance in non-Hodgkin lymphomas

Mounting evidence has proved that cellular adhesion confers resistance to chemotherapy in multiple lymphomas. The molecular mechanism underlying cell adhesion-mediated drug resistance (CAM-DR) is, however, poorly understood. In this study, we investigated the expression and biologic function of histamine-releasing factor (HRF) in non-Hodgkin lymphomas (NHLs). Clinically, by immunohistochemistry analysis we observed obvious up-regulation of HRF in NHLs including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL) and natural killer (NK)/T-cell lymphoma. Functionally, overexpression and knockdown of HRF demonstrated the antiapoptotic effect of HRF in NHL cells, which may be associated with activation of the p-CREB/BCL-2 signaling pathway. Moreover, cell adhesion assay demonstrated that adhesion to fibronectin (FN) or HS-5 up-regulated HRF expression, while knockdown of HRF resulted in decreased cell adhesion, which led to reversed CAM-DR. Our finding supports the role of HRF in NHL cell apoptosis, adhesion and drug resistance, and may provide a clinical therapeutic target for CAM-DR in NHL.