Novel roles of TMEM100: inhibition metastasis and proliferation of hepatocellular carcinoma

TMEM100 acts as a TAK1 receptor that prevents pathological cardiac hypertrophy progression

Pathological cardiac hypertrophy is the primary cause of heart failure, yet its underlying mechanisms remain incompletely understood. Transmembrane protein 100 (TMEM100) plays a role in various disorders, such as nervous system disease, pain and tumorigenesis, but its function in pathological cardiac hypertrophy is still unknown. In this study, we observed that TMEM100 is upregulated in cardiac hypertrophy. Functional investigations have shown that adeno-associated virus 9 (AAV9) mediated-TMEM100 overexpression mice attenuates transverse aortic constriction (TAC)-induced cardiac hypertrophy, including cardiomyocyte enlargement, cardiac fibrosis, and impaired heart structure and function. We subsequently demonstrated that adenoviral TMEM100 (AdTMEM100) mitigates phenylephrine (PE)-induced cardiomyocyte hypertrophy and downregulates the expression of cardiac hypertrophic markers in vitro, whereas TMEM100 knockdown exacerbates cardiomyocyte hypertrophy. The RNA sequences of the AdTMEM100 group and control group revealed that TMEM100 was involved in oxidative stress and the MAPK signaling pathway after PE stimulation. Mechanistically, we revealed that the transmembrane domain of TMEM100 (amino acids 53-75 and 85-107) directly interacts with the C-terminal region of TAK1 (amino acids 1-300) and inhibits the phosphorylation of TAK1 and its downstream molecules JNK and p38. TAK1-binding-defective TMEM100 failed to inhibit the activation of the TAK1-JNK/p38 pathway. Finally, the application of a TAK1 inhibitor (iTAK1) revealed that TAK1 is necessary for TMEM100-mediated cardiac hypertrophy. In summary, TMEM100 protects against pathological cardiac hypertrophy through the TAK1-JNK/p38 pathway and may serve as a promising target for the treatment of cardiac hypertrophy.

Regulation of TMEM100 expression by epigenetic modification, effects on proliferation and invasion of esophageal squamous carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a prevalent malignancy with a high morbidity and mortality rate. TMEM100 has been shown to be suppressor gene in a variety of tumors, but there are no reports on the role of TMEM100 in esophageal cancer (EC).

AIM

To investigate epigenetic regulation of TMEM100 expression in ESCC and the effect of TMEM100 on ESCC proliferation and invasion.

METHODS

Firstly, we found the expression of TMEM100 in EC through The Cancer Genome Atlas database. The correlation between TMEM100 gene expression and the survival of patients with EC was further confirmed through Kaplan-Meier analysis. We then added the demethylating agent 5-AZA to ESCC cell lines to explore the regulation of TMEM100 expression by epigenetic modification. To observe the effect of TMEM100 expression on tumor proliferation and invasion by overexpressing TMEM100. Finally, we performed gene set enrichment analysis using the Kyoto Encyclopaedia of Genes and Genomes Orthology-Based Annotation System database to look for pathways that might be affected by TMEM100 and verified the effect of TMEM100 expression on the mitogen-activated protein kinases (MAPK) pathway.

RESULTS

In the present study, by bioinformatic analysis we found that TMEM100 was lowly expressed in EC patients compared to normal subjects. Kaplan-meier survival analysis showed that low expression of TMEM100 was associated with poor prognosis in patients with EC. Then, we found that the demethylating agent 5-AZA resulted in increased expression of TMEM100 in ESCC cells [quantitative real-time PCR (qRT-PCR) and western blotting]. Subsequently, we confirmed that overexpression of TMEM100 leads to its increased expression in ESCC cells (qRT-PCR and western blotting). Overexpression of TMEM100 also inhibited proliferation, invasion and migration of ESCC cells (cell counting kit-8 and clone formation assays). Next, by enrichment analysis, we found that the gene set was significantly enriched in the MAPK signaling pathway. The involvement of TMEM100 in the regulation of MAPK signaling pathway in ESCC cell was subsequently verified by western blotting.

CONCLUSION

TMEM100 is a suppressor gene in ESCC, and its low expression may lead to aberrant activation of the MAPK pathway. Promoter methylation may play a key role in regulating TMEM100 expression.

Transmembrane Protein 100 Inhibits the Progression of Colorectal Cancer by Promoting the Ubiquitin/Proteasome Degradation of HIF-1α

Transmembrane protein 100 (TMEM100) is involved in embryonic cardiovascular system development. However, the biological role of TMEM100 in human cancers, particularly colorectal cancer (CRC), is unclear. In this study, tissue microarrays were stained using immunohistochemistry methods to evaluate the association between TMEM100 levels and clinic-pathological features for CRC. Kaplan–Meier and log-rank tests revealed that decreased levels of TMEM100 correlated with shorter overall survival. Cox regression revealed that reduced levels of TMEM100 was an independent prognostic factor for detrimental survival in CRC. A lentiviral vector was used to overexpress TMEM100 in HCT116 cells, and small interfering RNA was used to knockdown TMEM100 in SW480 cells. The CCK-8 assay, colony formation analysis, cell cycle analysis, cell migration assay, mouse xenograft model and mouse lung metastasis model showed that TMEM100 suppressed CRC cell proliferation and migration in vitro and in vivo. IHC scores of TMEM100 and HIF-1α were significantly negatively correlated. A half-time determination analysis in which cells were treated with cycloheximide revealed that TMEM100 shortened the HIF-1α half-life. Further immunoprecipitation experimental results showed that TMEM100 promoted the ubiquitination of HIF-1α, which caused HIF-1α degradation via the 26S proteasome pathway. Angiogenesis assay and migration assay results revealed that TMEM100 suppressed the migration and angiogenesis induction capacities of HCT116 cells, but this inhibitory effect was abolished when HIF-1α degradation was blocked by MG132 treatment. These results indicated that TMEM100 inhibited the migration and the angiogenesis induction capacities of CRC cells by enhancing HIF-1α degradation via ubiquitination/proteasome pathway.

Circulating microRNA sequencing revealed miRNome patterns in hematology and oncology patients aiding the prognosis of invasive aspergillosis

Invasive aspergillosis (IA) may occur as a serious complication of hematological malignancy. Delays in antifungal therapy can lead to an invasive disease resulting in high mortality. Currently, there are no well-established blood circulating microRNA biomarkers or laboratory tests which can be used to diagnose IA. Therefore, we aimed to define dysregulated miRNAs in hematology and oncology (HO) patients to identify biomarkers predisposing disease. We performed an in-depth analysis of high-throughput small transcriptome sequencing data obtained from the whole blood samples of our study cohort of 50 participants including 26 high-risk HO patients and 24 controls. By integrating in silico bioinformatic analyses of small noncoding RNA data, 57 miRNAs exhibiting significant expression differences (P < 0.05) were identified between IA-infected patients and non-IA HO patients. Among these, we found 36 differentially expressed miRNAs (DEMs) irrespective of HO malignancy. Of the top ranked DEMs, we found 14 significantly deregulated miRNAs, whose expression levels were successfully quantified by qRT-PCR. MiRNA target prediction revealed the involvement of IA related miRNAs in the biological pathways of tumorigenesis, the cell cycle, the immune response, cell differentiation and apoptosis.

GATA binding protein 5-mediated transcriptional activation of transmembrane protein 100 suppresses cell proliferation, migration and epithelial-to-mesenchymal transition in prostate cancer DU145 cells

It has been reported that transmembrane protein 100 (TMEM100) acts as a tumor regulator in several types of cancers. However, whether the expression of TMEM100 is associated with the development and prognosis of prostate cancer (PCa) remains elusive. Therefore, the present study aimed to uncover the role of GATA binding protein 5 (GATA5)-mediated activation of TMEM100 in the proliferation, migration and epithelial-to-mesenchymal transition (EMT) of PCa cells. The expressions of TMEM100 and GATA5 in PCa patients were analyzed by the GEPIA database. The binding site of GATA5 and TMEM100 promoter was predicted by the JASPAR database. Expressions of TMEM100 and GATA5 in PCa cells were detected by qRT-PCR and Western blot analysis. Cell Counting Kit 8 and colony formation assays were performed to measure cell proliferation. In addition, cell migration, invasion and the expression of EMT-associated proteins were evaluated using wound healing, transwell assay and Western blotting assays, respectively. The bioinformatics analysis revealed that TMEM100 was downregulated in PCa and was associated with overall survival of PCa. In addition, TMEM10 overexpression attenuated cell proliferation, migration, invasion and EMT in PCa cells. The interaction between TMEM100 and GATA5 was verified using dual luciferase reporter and chromatin immunoprecipitation assays. Furthermore, the results showed that GATA5 was downregulated and GATA5 silencing reversed the inhibitory effects of TMEM10 on PCa cells. Overall, the current study suggested that the GATA5-mediated transcriptional activation of TMEM100 could affect the behavior of PCa cells and was associated with poor prognosis in PCa.

TMEM130 regulates cell migration through DNA methylation in nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC), the common malignant head and neck cancer, is highly prevalent in southern China. The molecular mechanism underlying NPC tumorigenesis is unclear. We used 5-Aza-CdR, a DNA methyltransferase inhibitor, to treat NPC cell lines and discovered that the expression of TMEM130 changed significantly compared with the untreatment cells. This study aimed to identify the relationship between the DNA methylation status of TMEM130 and NPC, and to explore the function of TMEM130 in NPC cell migration.

METHODS

qRT-PCR was performed to investigate the transcriptional expression of TMEM130 in NPC. Bisulfite sequencing PCR and 5-Aza-CdR treatment were used to detect the methylation level of the TMEM130 promoter. Gene Expression Omnibus (GEO) datasets were obtained to identifiy the methylation status and mRNA expression of TMEM130 in NPC and normal control tissues. Transwell and western blot analyses were used to detect cell migration ability after transfection of TMEM130/NC plasmids in NPC cells.

RESULTS

The transcriptional expression of TMEM130 was decreased in NPC cell lines compared with in the NP69 cell line. TMEM130 promoter was significantly hyper methylated in three NPC cell lines (C666, CNE, and HONE) but hypo methylated in NP69 cells. The methylation level was higher in NPC than normal control tissues. Additionally, treatment of NPC cells with 5-Aza-CdR increased the TMEM130 mRNA expression level. Overexpression of TMEM130 in NPC cell lines suppressed cell migration ability and affected some epithelial-mesenchymal transition-associated gene expression.

CONCLUSIONS

This study is the first to investigate the expression and function of TMEM130 in NPC. It was found that TMEM130 hyper methylation might contribute to NPC migration and this gene might act as a tumor suppressor gene. TMEM130 is a promising biomarker for NPC diagnosis.

DNA methylation-mediated down-regulation of TMEM130 promotes cell migration in breast cancer

BACKGROUND

Breast cancer is the most common female cancer worldwide. DNA methylation is a common modification in epigenetics and affects the prognosis of breast cancer by changing gene expression. In the present study, we aim to investigate the role of DNA methylation in TMEM130 gene expression, and the function of TMEM130 in breast cancer cell migration.

METHODS

The transcriptional expression of TMEM130 was detected by qRT-PCR in breast cancer cell lines and tissues. Bisulfite sequencing PCR (BSP) was used to confirm the methylation status of TMEM130 promoter. Then, TMEM130 was transfected in breast cancer cell lines and to explore its role in cell migration by Transwell and western blot.

RESULTS

TMEM130 mRNA expression was decreased in breast cancer cell lines and tissues, and consistent with the data in The Cancer Genome Atlas (TCGA). The promoter of TMEM130 was hypermethylated in breast cancer and the expression of TMEM130 could be restored by the methyltransferase inhibitor. Overexpression of TMEM130 could inhibit cell migration ability in breast cancer cell lines.

CONCLUSION

Taken together, these results indicate TMEM130 downregulation and hypermethylation might contribute to breast cancer migration and TMEM130 might be a promising biomarker for breast cancer.

Identification of the circRNA-miRNA-mRNA Regulatory Network in Bladder Cancer by Bioinformatics Analysis

In recent years, increasing evidence shows that circular RNA (circRNA) disorder is closely related to tumorigenesis and cancer progression. However, the regulatory functions of most circRNAs in bladder cancer (BCa) remain unclear. This study was aimed at exploring the molecular regulatory mechanism of circRNAs in BCa. We obtained four datasets of circRNA, microRNA (miRNA), and messenger (mRNA) expression profiles from the Gene Expression Omnibus and The Cancer Genome Atlas microarray databases and identified 434, 367, and 4799/4841 differentially expressed circRNAs, miRNAs, and mRNAs, respectively. With these differentially expressed RNAs, we established a circRNA-miRNA-mRNA targeted interaction network. A total of 18, 24, and 51 central circRNAs, miRNAs, and mRNAs were identified, respectively. Among them, the top 10 mRNAs that had high connectivity with other circRNAs and miRNAs were regarded as hub genes. We detected the expression levels of these 10 mRNAs in 16 pairs of BCa tissues and adjacent normal tissues through quantitative real-time polymerase chain reaction. The differentially expressed mRNAs and central mRNAs were enriched in the processes and pathways that are associated with the growth, differentiation, proliferation, and apoptosis of tumor cells. The outstanding genes (CDCA4, GATA6, LATS2, RHOB, ZBTB4, and ZFPM2) also interacted with numerous drugs, indicating their potency as biomarkers and drug targets. The findings of this study provide a deep understanding of the circRNA-related competitive endogenous RNA regulatory mechanism in BCa pathogenesis.

The association of immunosurveillance and distant metastases in colorectal cancer

Background

Colorectal cancer (CRC) is the third most common malignancy worldwide, but the key driver to distant metastases is still unknown. This study aimed to elucidate the link between immunosurveillance and organotropism of metastases in CRC by evaluating different gene signatures and pathways.

Material and methods

CRC patients undergoing surgery at the Department of General, Visceral and Transplantation Surgery at the Ludwig-Maximilian University Hospital Munich (Munich, Germany) were screened and categorized into M0 (no distant metastases), HEP (liver metastases) and PER (peritoneal carcinomatosis) after a 5-year follow-up. Six patients of each group were randomly selected to conduct a NanoString analysis, which includes 770 genes. Subsequently, all genes were further analyzed by gene set enrichment analysis (GSEA) based on seven main cancer-associated databases.

Results

Comparing HEP vs. M0, the gene set associated with the Toll-like receptor (TLR) cascade defined by the Reactome database was significantly overrepresented in HEP. HSP90B1, MAPKAPK3, PPP2CB, PPP2R1A were identified as the core enrichment genes. The immunologic signature pathway GSE6875_TCONV_VS_FOXP3_KO_TREG_DN with FOXP3 as downstream target was significantly overexpressed in M0. RB1, TMEM 100, CFP, ZKSCAN5, DDX50 were the core enrichment genes. Comparing PER vs. M0 no significantly differentially expressed gene signatures were identified.

Conclusion

Chronic inflammation might enhance local tumor growth. This is the first study identifying immune related gene sets differentially expressed between patients with either liver or peritoneal metastases. The present findings suggest that the formation of liver metastases might be associated with TLR-associated pathways. In M0, a high expression of FOXP3 + tumor infiltrating lymphocytes (TILs) seemed to prevent at least in part metastases. Thus, these correlative findings lay the cornerstone to further studies elucidating the underlying mechanisms of organotropism of metastases.

TMEM100 negatively regulated by microRNA‑106b facilitates cellular apoptosis by suppressing survivin expression in NSCLC

Non‑small cell lung cancer (NSCLC) is a common malignant tumour. Nevertheless, the 5‑year survival rate of NSCLC patients remains poor. Thus, identifying critical factors involved in regulating the progression of NSCLC is important for providing potential treatment targets. In the present study, it was observed that transmembrane protein 100 (TMEM100) was significantly downregulated in NSCLC tissues compared with paired peritumoral tissues. Decreased TMEM100 expression was associated with poor clinical outcomes in NSCLC patients. Moreover, TMEM100 overexpression inhibited colony formation and facilitated apoptosis by suppressing survivin expression in NSCLC cells, whereas TMEM100 knockdown had the opposite effect. In addition, microRNA (miR)‑106b, a miR with controversial roles in different human cancers, was upregulated in NSCLC and directly downregulated TMEM100 expression. The roles of miR‑106b in cell survival were mitigated by the restoration of TMEM100. The aforementioned results indicated that TMEM100 induced cell apoptosis and inhibited cell survival by serving as a tumour suppressor and that miR‑106b‑mitigatedTMEM100 expression defined a potentially oncogenic pathway in NSCLC.

TMEM100 expression suppresses metastasis and enhances sensitivity to chemotherapy in gastric cancer

The gene encoding transmembrane protein 100 (TMEM100) was first discovered to be transcribed by the murine genome. It has been recently proven that TMEM100 contributes to hepatocellular carcinoma and non-small-cell lung carcinoma (NSCLC). This study investigates the impact of TMEM100 expression on gastric cancer (GC). TMEM100 expression was remarkably downregulated in GC samples compared to the surrounding non-malignant tissues (p < 0.01). Excessive TMEM100 expression prohibited the migration and invasion of GC cells without influencing their growth. However, TMEM100 knockdown restored their migration and invasion potential. Additionally, TMEM100 expression restored the sensitivity of GC cells to chemotherapeutic drugs such as 5-fluouracil (5-FU) and cisplatin. In terms of TMEM100 modulation, it was revealed that BMP9 rather than BMP10, is the upstream modulator of TM3M100. HIF1α downregulation modulated the impact of TMEM100 on cell migration, chemotherapy sensitivity and invasion in GC cells. Eventually, the in vivo examination of TMEM100 activity revealed that its upregulation prohibits the pulmonary metastasis of GC cells and increases the sensitivity of xenograft tumors to 5-FU treatment. In conclusion, TMEM100 serves as a tumor suppressor in GC and could be used as a promising target for the treatment of GC and as a predictor of GC clinical outcome.

Identification and analysis of long non-coding RNA related miRNA sponge regulatory network in bladder urothelial carcinoma

Background

The aim of this study was to investigate the regulatory network of lncRNAs as competing endogenous RNAs (ceRNA) in bladder urothelial carcinoma (BUC) based on gene expression data derived from The Cancer Genome Atlas (TCGA).

Materials and methods

RNA sequence profiles and clinical information from 414 BUC tissues and 19 non-tumor adjacent tissues were downloaded from TCGA. Differentially expressed RNAs derived from BUC and non-tumor adjacent samples were identified using the R package “edgeR”. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed using the “clusterProfiler” package. Gene ontology and protein–protein interaction (PPI) networks were analyzed for the differentially expressed mRNAs using the “STRING” database. The network for the dysregulated lncRNA associated ceRNAs was then constructed for BUC using miRcode, miRTarBase, miRDB, and TargetScan. Cox regression analysis was performed to identify independent prognostic RNAs associated with BUC overall survival (OS). Survival analysis for the independent prognostic RNAs within the ceRNA network was calculated using Kaplan–Meier curves.

Results

Based on our analysis, a total of 666, 1819 and 157 differentially expressed lncRNAs, mRNAs and miRNAs were identified respectively. The ceRNA network was then constructed and contained 59 lncRNAs, 23 DEmiRNAs, and 52 DEmRNAs. In total, 5 lncRNAs (HCG22, ADAMTS9-AS1, ADAMTS9-AS2, AC078778.1, and AC112721.1), 2 miRNAs (hsa-mir-145 and hsa-mir-141) and 6 mRNAs (ZEB1, TMEM100, MAP1B, DUSP2, JUN, and AIFM3) were found to be related to OS. Two lncRNAs (ADAMTS9-AS1 and ADAMTS9-AS2) and 4 mRNA (DUSP2, JUN, MAP1B, and TMEM100) were validated using GEPIA. Thirty key hub genes were identified using the ranking method of degree. KEGG analysis demonstrated that the majority of the DEmRNAs were involved in pathways associated with cancer.

Conclusion

Our findings provide an understanding of the important role of lncRNA–related ceRNAs in BUC. Additional experimental and clinical validations are required to support our findings.

Integrative analysis of the lncRNA-associated ceRNA network reveals lncRNAs as potential prognostic biomarkers in human muscle-invasive bladder cancer

Background

Long noncoding RNAs (lncRNAs) play important roles in competing endogenous RNA (ceRNA) networks involved in the development and progression of various cancers, including muscle-invasive bladder cancer (MIBC).

Purpose

This study aims to construct the lncRNA-associated ceRNA network and identify lncRNA signatures correlated with the clinical features of MIBC tissue samples from The Cancer Genome Atlas (TGCA) database.

Methods

The differential expression profiles of MIBC associated lncRNAs, miRNAs and mRNAs were obtained from TCGA. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to determine the principal functions of significantly dysregulated mRNAs. The dysregulated lncRNA-associated ceRNA network of MIBC was constructed based on the bioinformatics data, and the correlations between lncRNA expression and clinical features were analyzed using a weighted gene coexpression network analysis (WGCNA). Six cancer specific lncRNAs from the ceRNA network were randomly selected to detect their expression in 32 paired MIBC tissue samples and 5 bladder cancer cell lines using quantitative real-time polymerase chain reaction (qRT-PCR).

Results

The ceRNA network was constructed with 30 lncRNAs, 13 miRNAs and 32 mRNAs. Seventeen lncRNAs in the ceRNA network correlated with certain clinical features, and only 1 lncRNA (MIR137HG) correlated with the overall survival (OS) of patients with MIBC (log-rank test P<0.05). GO and KEGG analyses revealed roles for the potential mRNA targets of MIR137HG in epithelial cell differentiation and the peroxisome proliferator-activated receptor (PPAR) and tumor necrosis factor (TNF) signaling pathways. The expression data from TCGA were highly consistent with the verification results of the MIBC tissue samples and bladder cancer cell lines.

Conclusion

These findings improve our understanding of the regulatory mechanism of the lncRNA-miRNA-mRNA ceRNA network and reveal potential lncRNAs as prognostic biomarkers of MIBC.

TMEM100 mediates inflammatory cytokines secretion in hepatic stellate cells and its mechanism research

Recent studies have shown that Transmembrane protein 100 (TMEM100) is a gene at locus 17q32 encoding a 134-amino acid protein with two hypothetical transmembrane domainsa, and first identified as a transcript from the mouse genome. As a downstream target gene of bone morphogenetic protein (BMP)-activin receptor-like kinase 1 (ALK1) signaling, it was activated to participate in inducing arterial endothelium differentiation, maintaining vascular integrity, promoting cell apoptosis, inhibiting metastasis and proliferation of cancer cells. However, evidence for the function of TMEM100 in inflammation is still limited. In this study, we explore the role of TMEM100 in inflammatory cytokine secretion and the role of MAPK signaling pathways in tumor necrosis factor-alpha (TNF-α)-induced TMEM100 expression in LX-2 cells. We found that the expression of TMEM100 was decreased markedly in human liver fibrosis tissues, and its expression was also inhibited in LX-2 cells induced by TNF-α, suggesting that it might be associated with the development of inflammation. Therefore, we demonstrated that overexpression of TMEM100 by transfecting pEGFP-C2-TMEM100 could lead to the down-regulation of IL-1β and IL-6 secretion. Moreover, we found that expression changes of TMEM100 could be involved in inhibition or activation of MAPK signaling pathways accompanied with regulating phosphorylation levels of ERK and JNK protein in response to TNF-α. These results suggested that TMEM100 might play an important role in the secretion of inflammatory cytokines (IL-1β and IL-6) of LX-2 cells induced by TNF-α, and MAPK (ERK and JNK) signaling pathways might participate in its induction of expression.

Transmembrane protein 100 is expressed in neurons and glia of dorsal root ganglia and is reduced after painful nerve injury

Introduction

Tmem100 modulates interactions between TRPA1 and TRPV1. The cell specificity of Tmem100 expression in dorsal root ganglia (DRGs) is not well defined, nor is the effect of peripheral nerve injury on Tmem100 expression.

Objective

This study was designed to determine the cell specificity of Tmem100 expression in DRG and its subcellular localization, and to examine how Tmem100 expression may be altered in painful conditions.

Methods

Dorsal root ganglion Tmem100 expression was determined by immunohistochemistry, immunoblot, and quantitative real-time PCR, and compared between various experimental rat pain models and controls.

Results

Tmem100 is expressed in both neurons and perineuronal glial cells in the rat DRG. The plasma membrane and intracellular localization of Tmem100 are identified in 83% ± 6% of IB4-positive and 48% ± 6% of calcitonin gene-related peptide-positive neurons, as well as in medium- and large-sized neurons, with its immunopositivity colocalized to TRPV1 (94% ± 5%) and TRPA1 (96% ± 3%). Tmem100 is also detected in the perineuronal satellite glial cells and in some microglia. Tmem100 protein is significantly increased in the lumbar DRGs in the complete Freund adjuvant inflammatory pain. By contrast, peripheral nerve injury by spinal nerve ligation diminishes Tmem100 expression in the injured DRG, with immunoblot and immunohistochemistry experiments showing reduced Tmem100 protein levels in both neurons and satellite glial cells of DRGs proximal to injury, whereas Tmem100 is unchanged in adjacent DRGs. The spared nerve injury model also reduces Tmem100 protein in the injured DRGs.

Conclusion

Our data demonstrate a pain pathology-dependent alteration of DRG Tmem100 protein expression, upregulated during CFA inflammatory pain but downregulated during neuropathic pain.

Expression of transmembrane protein 41A is associated with metastasis via the modulation of E‑cadherin in radically resected gastric cancer

Gastric cancer (GC) is one of the most commonly occurring malignancies worldwide, and metastasis is one of the key processes affecting the prognosis of GC. TMEM41A, which belongs to a group of transmembrane proteins that participate in signaling pathways and tumor development, is a 264‑amino acid protein encoded by a gene mapped to human chromosome The exact role of TMEM41A in GC has not been determined to date. In the present study, the expression of TMEM41A in 147 cases of GC was analyzed with immunohistohemistry and the prognoses of these patients were analyzed. It was revealed that TMEM41A was highly expressed in GC tissues, and may be associated with the progression of GC and poor prognosis. The expression of TMEM41A was observed to be correlated with lymph node metastasis, distant metastasis and advanced tumor, node and metastasis stages. Knockdown of TMEM41A in vitro and in vivo decreased the GC cell migration ability by regulating epithelial‑to‑mesenchymal transition and cell autophagy, via the upregulation of E‑cadherin and downregulating N‑cadherin expression in GC cells by reverse transcription‑quantitative polymerase chain reaction (PCR), semi‑PCR and western blotting. Furthermore, TMEM41A upregulation was associated with the upregulation of p62 and altered the conversion of light chain (LC)3‑1 into LC3‑2 by western blotting. Knockdown of TMEM41A was also observed to affect tumor metastasis in nude mice. Therefore, TMEM41A may be considered as a novel therapeutic target for the treatment of GC‑associated metastasis.

The expression of Transmembrane Protein 100 is regulated by alterations in calcium signaling rather than endoplasmic reticulum stress

Transmembrane protein 100 (TMEM100) comprises 134 amino acid residues and is highly conserved among vertebrates. Tmem100 has been recently reported as a key factor in angiogenesis, pain transmission, and tumor suppression. Although the importance of TMEM100 function is well supported, few studies have elucidated its expression mechanism. In the current study, we found that activating transcription factor 6α, a transcription factor activated by endoplasmic reticulum (ER) stress, enhanced Tmem100 promoter activity. Two ER stress response element-like motifs were identified in the mouse Tmem100 promoter region. However, additional experiments using another type of ER stress inducer demonstrated that calcium signaling was more important than ER stress in the regulation of TMEM100 expression. Intracellular calcium signaling controls biological processes such as cell proliferation and embryonic development. This study suggested that TMEM100 performs various functions in response to alterations in calcium signaling in addition to those in response to ER stress.

SPP1 and AGER as potential prognostic biomarkers for lung adenocarcinoma

Overdue treatment and prognostic evaluation lead to low survival rates in patients with lung adenocarcinoma (LUAD). To date, effective biomarkers for prognosis are still required. The aim of the present study was to screen differentially expressed genes (DEGs) as biomarkers for prognostic evaluation of LUAD. DEGs in tumor and normal samples were identified and analyzed for Kyoto Encyclopedia of Genes and Genomes/Gene Ontology functional enrichments. The common genes that are up and downregulated were selected for prognostic analysis using RNAseq data in The Cancer Genome Atlas. Differential expression analysis was performed with 164 samples in GSE10072 and GSE7670 datasets. A total of 484 DEGs that were present in GSE10072 and GSE7670 datasets were screened, including secreted phosphoprotein 1 (SPP1) that was highly expressed and DEGs ficolin 3, advanced glycosylation end-product specific receptor (AGER), transmembrane protein 100 that were lowly expressed in tumor tissues. These four key genes were subsequently verified using an independent dataset, GSE19804. The gene expression model was consistent with GSE10072 and GSE7670 datasets. The dysregulation of highly expressed SPP1 and lowly expressed AGER significantly reduced the median survival time of patients with LUAD. These findings suggest that SPP1 and AGER are risk factors for LUAD, and these two genes may be utilized in the prognostic evaluation of patients with LUAD. Additionally, the key genes and functional enrichments may provide a reference for investigating the molecular expression mechanisms underlying LUAD.

Hypoxia-Inducible Factor 2α Mutation-Related Paragangliomas Classify as Discrete Pseudohypoxic Subcluster

Recently, activating mutations of the hypoxia-inducible factor 2α gene (HIF2A/EPAS1) have been recognized to predispose to multiple paragangliomas (PGLs) and duodenal somatostatinomas associated with polycythemia, and ocular abnormalities. Previously, mutations in the SDHA/B/C/D, SDHAF2, VHL, FH, PHD1, and PHD2 genes have been associated with HIF activation and the development of pseudohypoxic (cluster-1) PGLs. These tumors overlap in terms of tumor location, syndromic presentation, and noradrenergic phenotype to a certain extent. However, they also differ especially by clinical outcome and by presence of other tumors or abnormalities. In the present study, we aimed to establish additional molecular differences between HIF2A and non-HIF2A pseudohypoxic PGLs. RNA expression patterns of HIF2A PGLs (n = 6) from 2 patients were compared with normal adrenal medullas (n = 8) and other hereditary pseudohypoxic PGLs (VHL: n = 13, SDHB: n = 15, and SDHD: n = 14). Unsupervised hierarchical clustering showed that HIF2A PGLs made up a separate cluster from other pseudohypoxic PGLs. Significance analysis of microarray yielded 875 differentially expressed genes between HIF2A and other pseudohypoxic PGLs after normalization to adrenal medulla (false discovery rate 0.01). Prediction analysis of microarray allowed correct classification of all HIF2A samples based on as little as three genes (TRHDE, LRRC63, IGSF10; error rate: 0.02). Genes with the highest expression difference between normal medulla and HIF2A PGLs were selected for confirmatory quantitative reverse transcriptase polymerase chain reaction. In conclusion, HIF2A PGLs show a characteristic expression signature that separates them from non-HIF2A pseudohypoxic PGLs. Unexpectedly, the most significantly differentially expressed genes have not been previously described as HIF target genes.

Low-expression of TMEM100 is associated with poor prognosis in non-small-cell lung cancer

Transmembrane protein 100 (TMEM100) was first identified as a transcript from the mouse genome. Recent studies have demonstrated that TMEM100 is involved in hepatocellular carcinoma (HCC) malignancy. However, the distribution and clinical significance of TMEM100 in non-small-cell lung carcinoma (NSCLC) remains poorly understood. This study aims to explore the significance of TMEM100 expression in NSCLC. We found that TMEM100 expression was significantly reduced in NSCLC tissues when compared with that in adjacent normal lung tissues (P<0.001). Kaplan-Meier survival analysis showed that overall survival of patients with lower expressions of TMEM100 was significantly shorter (n=152, P<0.05). In addition, TMEM100 overexpression in NSCLC cell lines inhibited cell proliferation in vitro and in vivo. Transwell migration and invasion assay showed that TMEM100 significantly suppressed the migration and invasion of NSCLC cell lines. In contrast, knocking down TMEM100 promoted NSCLC proliferation and migration. Finally, we found that TMEM100 worked as a cancer suppressor gene mainly by inhibiting the TNF signaling pathway. In conclusion, TMEM100 acted as a tumor suppressor in NSCLC and may prove to be a potential prognostic biomarker and therapeutic target for NSCLC.

Upregulation and biological function of transmembrane protein 119 in osteosarcoma

Osteosarcoma is suggested to be caused by genetic and molecular alterations that disrupt osteoblast differentiation. Recent studies have reported that transmembrane protein 119 (TMEM119) contributes to osteoblast differentiation and bone development. However, the level of TMEM119 expression and its roles in osteosarcoma have not yet been elucidated. In the present study, TMEM119 mRNA and protein expression was found to be up-regulated in osteosarcoma compared with normal bone cyst tissues. The level of TMEM119 protein expression was strongly associated with tumor size, clinical stage, distant metastasis and overall survival time. Moreover, gene set enrichment analysis (GSEA) of the Gene Expression Omnibus (GEO) GSE42352 dataset revealed TMEM119 expression in osteosarcoma tissues to be positively correlated with cell cycle, apoptosis, metastasis and TGF-β signaling. We then knocked down TMEM119 expression in U2OS and MG63 cells using small interfering RNA, which revealed that downregulation of TMEM119 could inhibit the proliferation of osteosarcoma cells by inducing cell cycle arrest in G0/G1 phase and apoptosis. We also found that TMEM119 knockdown significantly inhibited cell migration and invasion, and decreased the expression of TGF-β pathway-related factors (BMP2, BMP7 and TGF-β). TGF-β application rescued the inhibitory effects of TMEM119 knockdown on osteosarcoma cell migration and invasion. Further in vitro experiments with a TGF-β inhibitor (SB431542) or BMP inhibitor (dorsomorphin) suggested that TMEM119 significantly promotes cell migration and invasion, partly through TGF-β/BMP signaling. In conclusion, our data support the notion that TMEM119 contributes to the proliferation, migration and invasion of osteosarcoma cells, and functions as an oncogene in osteosarcoma.