TMED2 Induces Cisplatin Resistance in Breast Cancer via Targeting the KEAP1-Nrf2 Pathway

OBJECTIVE

Cisplatin is the first-line treatment for breast cancer, but it faces challenges of drug resistance. This study investigated new molecular mechanisms underlying cisplatin resistance in breast cancer.

METHODS

We analyzed sequencing data from the TCGA database to identify potential associations between transmembrane emp24 protein transport domain containing 2 (TMED2) and breast cancer. Western blotting, real-time PCR, CCK-8, and TUNEL assays were used to measure the effects and molecular mechanism of TMED2 on cisplatin resistance in MCF-7 and MDA-MB-231 cell lines.

RESULTS

TMED2 was overexpressed in breast cancer and associated with poor prognosis. TMED2 increased cisplatin resistance in breast cancer cells in vitro via promoting ubiquitination of Kelch-like ECH-associated protein 1 (KEAP1), relieving inhibition of KEAP1 on nuclear factor erythroid 2-related factor 2 (Nrf2), and increasing expression of downstream drug resistance related genes, such as heme oxygenase 1 (HO-1) and NAD (P) H quinone oxidoreductase 1 (NQO1).

CONCLUSION

We identified a new molecular mechanism by which TMED2 affects cisplatin resistance in breast cancer. Our results provide theoretical guidance for future clinical applications.

VIRMA facilitates intrahepatic cholangiocarcinoma progression through epigenetic augmentation of TMED2 and PARD3B mRNA stabilization

BACKGROUND

N6-methyladenine modification of RNA, a critical component of the regulatory role at the post-transcriptional level, has a crucial effect on tumor development and progression. vir-Like m6A methyltransferase associated (VIRMA) has been recently discovered as an N6-methyladenine methyltransferase; however, its specific role in intrahepatic cholangiocarcinoma (ICC) remains to be investigated in-depth.

METHODS

VIRMA expression and its association with clinicopathological characteristics were evaluated using The Cancer Genome Atlas (TCGA) dataset and tissue microarrays. In vivo and in vitro assays were performed to determine the role of VIRMA in ICC proliferation and metastasis. The underlying mechanism by which VIRMA influences ICC was clarified by RNA sequencing (RNA-seq), methylated RNA immunoprecipitation sequencing (MeRIP-seq), SLAM sequencing (SLAM-seq), RNA immunoprecipitation, a luciferase reporter assay, and chromatin immunoprecipitation assay.

RESULTS

VIRMA showed high expression in ICC tissues, and this finding predicted a dismal prognostic outcome. The high expression of VIRMA in ICC was due to the demethylation of H3K27me3 modification in the promoter region. Functionally, VIRMA is required for the endothelial-mesenchymal transition (EMT) process in ICC cells, as shown by multiple ICC models in in vitro and in vivo experiments. Mechanistically, multi-omics analysis using ICC cells demonstrated that TMED2 and PARD3B were the direct downstream target of VIRMA. The methylated TMED2 and PARD3B transcripts were directly recognized by HuR, which exerted stabilizing effects on its bound RNA. VIRMA-induced expression of TMED2 and PARD3B activated the Akt/GSK/β-catenin and MEK/ERK/Slug signaling pathways, thereby promoting ICC proliferation and metastasis.

CONCLUSIONS

The present study showed that VIRMA plays a critical role in ICC development by stabilizing TMED2 and PARD3B expression through the m6A-HuR-mediated mechanism. Thus, demonstrating VIRMA and its pathway as candidate therapeutic targets for ICC treatment.

ER-Golgi-localized proteins TMED2 and TMED10 control the formation of plasma membrane lipid nanodomains

To promote infections, pathogens exploit host cell machineries such as structural elements of the plasma membrane. Studying these interactions and identifying molecular players are ideal for gaining insights into the fundamental biology of the host cell. Here, we used the anthrax toxin to screen a library of 1,500 regulatory, cell-surface, and membrane trafficking genes for their involvement in the intoxication process. We found that endoplasmic reticulum (ER)-Golgi-localized proteins TMED2 and TMED10 are required for toxin oligomerization at the plasma membrane of human cells, an essential step dependent on localization to cholesterol-rich lipid nanodomains. Biochemical, morphological, and mechanistic analyses showed that TMED2 and TMED10 are essential components of a supercomplex that operates the exchange of both cholesterol and ceramides at ER-Golgi membrane contact sites. Overall, this study of anthrax intoxication led to the discovery that lipid compositional remodeling at ER-Golgi interfaces fully controls the formation of functional membrane nanodomains at the cell surface.

Transmembrane p24 trafficking protein 2 regulates inflammation through the TLR4/NF-κB signaling pathway in lung adenocarcinoma

Background

To investigate the role of transmembrane p24 trafficking protein 2 (TMED2) in lung adenocarcinoma (LUAD) and determine whether TMED2 knockdown could inhibit LUAD in vitro and in vivo.

Methods

TIMER2.0, Kaplan-Meier plotter, gene set enrichment analysis (GSEA), Target Gene, and pan-cancer systems were used to predict the potential function of TMED2. Western blotting and immunohistochemistry were performed to analyze TMED2 expression in different tissues or cell lines. The proliferation, development, and apoptosis of LUAD were observed using a lentivirus-mediated TMED2 knockdown. Bioinformatics and western blot analysis of TMED2 against inflammation via the TLR4/NF-κB signaling pathway were conducted.

Results

TMED2 expression in LUAD tumor tissues was higher than that in normal tissues and positively correlated with poor survival in lung cancer and negatively correlated with apoptosis in LUAD. The expression of TMED2 was higher in tumors or HCC827 cells. TMED2 knockdown inhibited LUAD development in vitro and in vivo and increased the levels of inflammatory factors via the TLR4/NF-κB signaling pathway. TMED2 was correlated with TME, immune score, TME-associated immune cells, their target markers, and some mechanisms and pathways, as determined using the TIMER2.0, GO, and KEGG assays.

Conclusions

TMED2 may regulate inflammation in LUAD through the TLR4/NF-κB signaling pathway and enhance the proliferation, development, and prognosis of LUAD by regulating inflammation, which provide a new strategy for treating LUAD by regulating inflammation.

Multi-Omics Analysis Identified TMED2 as a Shared Potential Biomarker in Six Subtypes of Human Cancer

Introduction

Cancer is one of the most common malignancies and the leading cause of death worldwide. As a member of the transmembrane emp24 domain (Tmed)/p24 family of proteins, TMED2 expression variations have been documented earlier in only a few subtypes of human cancers, and the multi-omics profiling of TMED2 as a shared biomarker in different other subtypes of human cancers remains to be uncovered.

Methods

In the current study, TMED2 multi-omics analysis in 24 major subtypes of human cancer was performed using different authentic online databases and bioinformatics analysis including UALCAN, Kaplan–Meier (KM) plotter, Human Protein Atlas (HPA), GENT2, MEXPRESS, cBioportal, STRING, DAVID, TIMER, and CTD.

Results

In general, the TMED2 expression in 24 major subtypes of human cancers was higher relative to normal controls and was also strongly associated with the lower overall survival (OS) and relapse-free survival (RFS) duration of CESC, ESCA, HNSC, KIRC, LIHC, and LUAD patients. This implies that TMED2 plays a significant role in the development and progression of these cancers. Furthermore, the TMED2 overexpression was also correlated with different clinicopathological features of CESC, ESCA, HNSC, KIRC, LIHC, and LUAD patients. TMED2-associated genes network was involved in 3 diverse pathways, and finally, few stronger correlations were also explored between TMED2 expression and its promoter methylation level, genetic alterations, and CD8+ T immune cells level.

Conclusion

In conclusion, via this in silico study, we have elucidated that TMED2 can serve as a shared diagnostic and prognostic biomarker in CESC, ESCA, HNSC, KIRC, LIHC, and LUAD patients of different clinicopathological features but, further in vitro and in vivo research should be carried out to confirm these findings.

Expression and Importance of TMED2 in Multiple Myeloma Cells

Objective

TMED2 is a member of the transmembrane emp24 domain (Tmed)/p24 protein family, which is significantly upregulated in breast cancer, ovarian cancer and other tumour tissues. The purpose of this study was to investigate the expression of TMED2 in MM cell lines and its effect on the biological behaviour of MM cell lines.

Methods

Real-time quantitative PCR (RT-qPCR) was used to detect the expression of TMED2 in MM cell lines, including MM.1S and RPMI 8226 cells, and lentivirus vector-mediated TMED2 gene silencing was used to further study the effect of the downregulation of TMED2 expression on cell viability, the cell cycle, and apoptosis.

Results

Based on the RT-qPCR results, the expression of the TMED2 mRNA was increased in the MM cell lines MM.1S and RPMI 8226 compared with endogenous control GAPDH. The expression of the TMED2 mRNA was substantially reduced after transfection of the shRNA targeting TMED2 (shTMED2) in both MM cell lines. The CCK-8 assay showed significant decreases in the viability of MM.1S and RPMI 8226 cells, suggesting that the TMED2 gene plays an important role in the proliferation of these two cell lines. The cell cycle of MM.1S and RPMI 8226 cells was substantially altered by shTMED2, as evidenced by the increased number of cells in G1 phase and decreased number of cells in S and G2/M phases. The FACS analysis revealed a significant increase in the apoptosis of MM.1S and RPMI 8226 cells due to the increased activity of Caspase 3/7, suggesting that the TMED2 gene is significantly related to the apoptosis of these two cell lines.

Conclusion

Based on these results, TMED2 may play an important role in the pathogenesis of MM. This novel study may contribute to further investigations of useful biomarkers and potential therapeutic targets in patients with MM.

Control of anterior GRadient 2 (AGR2) dimerization links endoplasmic reticulum proteostasis to inflammation

Anterior gradient 2 (AGR2) is a dimeric protein disulfide isomerase family member involved in the regulation of protein quality control in the endoplasmic reticulum (ER). Mouse AGR2 deletion increases intestinal inflammation and promotes the development of inflammatory bowel disease (IBD). Although these biological effects are well established, the underlying molecular mechanisms of AGR2 function toward inflammation remain poorly defined. Here, using a protein-protein interaction screen to identify cellular regulators of AGR2 dimerization, we unveiled specific enhancers, including TMED2, and inhibitors of AGR2 dimerization, that control AGR2 functions. We demonstrate that modulation of AGR2 dimer formation, whether enhancing or inhibiting the process, yields pro-inflammatory phenotypes, through either autophagy-dependent processes or secretion of AGR2, respectively. We also demonstrate that in IBD and specifically in Crohn's disease, the levels of AGR2 dimerization modulators are selectively deregulated, and this correlates with severity of disease. Our study demonstrates that AGR2 dimers act as sensors of ER homeostasis which are disrupted upon ER stress and promote the secretion of AGR2 monomers. The latter might represent systemic alarm signals for pro-inflammatory responses.

The circular RNA CDR1as regulate cell proliferation via TMED2 and TMED10

Background

Circular RNAs (CircRNAs) are biologically active RNAs. CDR1as is one such circRNA previously reported to be a microRNA-7 (miR-7) sponge, thereby regulating associated gene expression. The specific underlying molecular mechanisms of CDR1as biology, however, remain largely unknown.

Methods

We performed CDR1as knockdown in order to explore its function in cell proliferation, migration, the cell cycle, and tumorigenesis. We further employed quantitative proteomic analyses and associated bioinformatics strategies to globally assess CDR1as-regulated proteins (CRPs). Western blotting and immunofluorescence staining were used to validate the proteomic results. We additionally investigated a specific link between TMED2, TMED10, and miR-7 via a dual-luciferase reporter system, and generated CDR1as knockout cell lines via CRISPR/Cas9 editing.

Results

We identified 353 proteins dysregulated upon CDR1as knockdown in 293 T cells. These CRPs were found to interact with one another and to play key roles in certain cellular pathways. Two such proteins, TMED2 and TMED10, were found to specifically contribute to the influence of CDR1as on cell proliferation. CDR1as may regulate these two TMED proteins through miR-7 sponging. We were able to further confirm these results using both CRISPRi cell lines and nude mouse models.

Conclusion

This study suggested that CDR1as may regulate cell proliferation via serving as a miR-7 sponge, thereby regulating TMED2 and TMED10 expression. These results are an invaluable template for future streamlined studies of circRNAs.

TMED2 Potentiates Cellular IFN Responses to DNA Viruses by Reinforcing MITA Dimerization and Facilitating Its Trafficking

Mediator of IRF3 activation (MITA), also known as stimulator of interferon genes (STING), plays a vital role in the innate immune responses to cytosolic dsDNA. The trafficking of MITA from the ER to perinuclear vesicles is necessary for its activation of the downstream molecules, which lead to the production of interferons and pro-inflammatory cytokines. However, the exact mechanism of MITA activation remains elusive. Here, we report that transmembrane emp24 protein transport domain containing 2 (TMED2) potentiates DNA virus-induced MITA signaling. The suppression or deletion of TMED2 markedly impairs the production of type I IFNs upon HSV-1 infection. TMED2-deficient cells harbor greater HSV-1 load than the control cells. Mechanistically, TMED2 associates with MITA only upon viral stimulation, and this process potentiates MITA activation by reinforcing its dimerization and facilitating its trafficking. These findings suggest an essential role of TMED2 in cellular IFN responses to DNA viruses.

RAB21 interacts with TMED10 and modulates its localization and abundance

Membrane trafficking controls vesicular transport of cargo between cellular compartments. Vesicular trafficking is essential for cellular homeostasis and dysfunctional trafficking is linked to several pathologies such as neurodegenerative diseases. Following endocytosis, early endosomes act as sorting stations of internalized materials, routing cargo toward various fates. One important class of membrane trafficking regulators are RAB GTPases. RAB21 has been associated with multiple functions and regulates integrin internalization, endosomal sorting of specific clathrin-independent cargo and autophagy. Although RAB21 is mostly associated with early endosomes, it has been shown to mediate a specific sorting event at the Golgi. From mass spectrometry data, we identified a GTP-favored interaction between RAB21 and TMED10 and 9, essential regulators of COPI and COPII vesicles. Using RAB21 knockout cells, we describe the role of RAB21 in modulating TMED10 Golgi localization. Taken together, our study suggests a new potential function of RAB21 in modulating TMED10 trafficking, with relevance to neurodegenerative disorders.

Summary: A small early endosomal RAB GTPase is found to interact with p24 family members, with potential impacts on p24 functions.

Increased expression of TMED2 is an unfavorable prognostic factor in patients with breast cancer

Background: We obtained 2 types of clones which were termed SC (sphere-shaped clone) and NSC (non-sphere-shaped clone) from 4T1 cells by monoclonal culture. SC and NSC were distinct in morphology, surface marker, metabolism and proliferation rate. With the transcriptome sequencing data analysis, we found TMED2 expressed higher in SCs. TMED2 was a member of the transmembrane emp24 domain and might play roles in cancer cell proliferation. However, its prognostic roles in breast cancer remained unknown. We aimed to investigate the prognostic values of TMED2 in patients with breast cancer.

Methods: We used UALCAN (http://ualcan.path.uab.edu) and the Human Protein Atlas (www.proteinatlas.org) to explore the TMED2 expression level and DNA methylation data between breast cancer and normal breast tissue. With Oncomine (www.oncomine.org), we investigated the copy number of TMED2 in breast cancer sample and normal breast tissue. We used the Kaplan–Meier Plotter database (http://kmplot.com/analysis) to analyze prognostic values of TMED2 mRNA expression in all breast cancers and in different intrinsic subtypes. Moreover, protein expression levels of TMED2 were confirmed by Western blot in breast cancer tissues and normal mammary tissue as well as SCs and NSCs.

Results: TMED2 significantly upregulated in breast cancer patients compared to normal mammary samples. Meanwhile, the increased expression of TMED2 mRNA was closely associated with reduced overall survival (OS) in all breast cancers, and with reduced OS in patients with ER-positive, Luminal A or Luminal B breast cancer subtypes. Moreover, western blot confirmed that TMED2 increased expressed was correlated with the reduced OS at protein levels.

Conclusion: Increased expression of TMED2 was significantly related to unfavorable outcomes in patients with breast cancer. Thus, we supposed TMED2 is oncogenic and a potential target for breast cancer therapy and these preliminary findings require further study to determine whether TMED2-targeting reagents might be developed for clinical application in breast cancer.

TMED2 promotes epithelial ovarian cancer growth

TMED2 is involved in morphogenesis of the mouse embryo and placenta. We found that expression of TMED2 was higher in epithelial ovarian cancer tissues than normal ovarian tissues. Silencing TMED2 decreased cell proliferation, migration, and invasion. Ectopic expression of TMED2 increased cell proliferation, migration and invasion. Silencing TMED2 inhibited ovarian cancer growth in mice. Silencing TMED2 inhibited IGF2/IGF1R/PI3K/Akt pathway. In agreement, ectopically expressed TMED2 activated IGF2/IGF1R/PI3K/Akt pathway. Mechanistic study revealed that TMED2 directly binds to AKT2, thereby facilitating its phosphorylation. We also found that TMED2 increased IGF1R expression by competing for miR-30a. Thus, TMED2 is oncogenic and a potential target for epithelial ovarian cancer therapy.