Silencing Transmembrane Protein 45B (TNEM45B) Inhibits Proliferation, Invasion, and Tumorigenesis in Osteosarcoma Cells

TMEM205 induces TAM/M2 polarization to promote cisplatin resistance in gastric cancer

Cisplatin (DDP) is a basic chemotherapy drug for gastric cancer (GC). With the increase of DDP drug concentration in clinical treatment, cancer cells gradually became resistant. Therefore, it is necessary to find effective therapeutic targets to enhance the sensitivity of GC to DDP. Studies have shown that Transmembrane protein 205 (TMEM205) is overexpressed in DDP-resistant human epidermoid carcinoma cells and correlates with drug resistance, and database analyses show that TMEM 205 is also overexpressed in GC, but its role in cisplatin-resistant gastric cancer remains unclear. In this study, we chose a variety of experiments in vivo and vitro, aiming to investigate the role of TMEM 205 in cisplatin resistance in gastric cancer. The results showed that TMEM 205 promoted proliferation, stemness, epithelial-mesenchymal transition (EMT), migration and angiogenesis of gastric cancer cells through activation of the Wnt/β-catenin signaling pathway. In addition, TMEM205 promotes GC progression by inducing M2 polarization of tumor-associated macrophages (TAMs). These results suggest that TMEM205 may be an effective target to regulate the sensitivity of GC to DDP, providing a new therapeutic direction for clinical treatment.

Multidimensional comprehensive and integrated analysis of the potential function of TMEM25 in renal clear cell carcinoma with low expression status

BACKGROUND

Transmembrane 25(TMEM25) stands out as a potential prognostic biomarker and therapeutic target in the realm of cancer, yet its precise mechanism of action within clear cell renal cell carcinoma (ccRCC) remains unclear.

MATERIALS AND METHODS

Gene expression data and clinically relevant information extracted from The Cancer Genome Atlas (TCGA) and Gene expression omnibus (GEO) databases unveil the expression patterns of TMEM25 within renal clear cell carcinoma, which reveals its prognostic and diagnostic significance. The protein expression data is available via the Human Protein Atlas (HPA) database. Further, qPCR experiments conducted on cells and tissues provide strong evidence of the gene's expression status. Additionally, they explore the correlations between TMEM25 expression and DNA methylation, gene mutations, immune cell infiltration, and drug sensitivity within this specific tumor context.

RESULTS

At both the RNA and protein levels, TMEM25 displays a noteworthy downregulation in expression, which is consistently linked to an unfavorable prognosis. Receiver Operating Characteristic (ROC) curve analysis, univariate and multivariate Cox regression analyses confirmed the ability of TMEM25 to diagnose and determine prognosis in ccRCC. Its expression related closely with various immune cell types, immune checkpoints, immune inhibitors, and MHC molecules. Within ccRCC tissues, TMEM25 DNA methylation levels are observed to be elevated, and this upregulation is observed across various conditions. TMEM25 mutations also have an impact on the prognosis of ccRCC patients and the results of drug sensitivity analyses are useful for clinical decision-making.

CONCLUSIONS

TMEM25 in ccRCC could potentially function as a tumor suppressor gene, holding substantial promise as a novel biomarker for diagnosing, treating, and prognosticating ccRCC patients.

The transmembrane proteins (TMEM) and their role in cell proliferation, migration, invasion, and epithelial-mesenchymal transition in cancer

Transmembrane proteins (TMEM) are located in the different biological membranes of the cell and have at least one passage through these cellular compartments. TMEM proteins carry out a wide variety of functions necessary to maintain cell homeostasis TMEM165 participates in glycosylation protein, TMEM88 in the development of cardiomyocytes, TMEM45A in epidermal keratinization, and TMEM74 regulating autophagy. However, for many TMEM proteins, their physiological function remains unknown. The role of these proteins is being recently investigated in cancer since transcriptomic and proteomic studies have revealed that exits differential expression of TMEM proteins in different neoplasms concerning cancer-free tissues. Among the cellular processes in which TMEM proteins have been involved in cancer are the promotion or suppression of cell proliferation, epithelial-mesenchymal transition, invasion, migration, intravasation/extravasation, metastasis, modulation of the immune response, and response to antineoplastic drugs. Inclusive data suggests that the participation of TMEM proteins in these cellular events could be carried out through involvement in different cell signaling pathways. However, the exact mechanisms not clear. This review shows a description of the involvement of TMEM proteins that promote or decrease cell proliferation, migration, and invasion in cancer cells, describes those TMEM proteins for which both a tumor suppressor and a tumor promoter role have been identified, depending on the type of cancer in which the protein is expressed. As well as some TMEM proteins involved in chemoresistance. A better characterization of these proteins is required to improve the understanding of the tumors in which their expression and function are altered; in addition to improving the understanding of the role of these proteins in cancer will show those TMEM proteins be potential candidates as biomarkers of response to chemotherapy or prognostic biomarkers or as potential therapeutic targets in cancer.

TMEM200A is a potential prognostic biomarker and correlated with immune infiltrates in gastric cancer

Background

Gastric cancer (GC) is one of the most common malignant tumors in the digestive system. Several transmembrane (TMEM) proteins are defined as tumor suppressors or oncogenes. However, the role and underlying mechanism of TMEM200A in GC remain unclear.

Methods

We analyzed the expression of TMEM200A in GC. Furthermore, the influence of TMEM200A on survival of GC patients was evaluated. The correlations between the clinical information and TMEM200A expression were analyzed using chi-square test and logistic regression. Relevant prognostic factors were identified performing univariate and multivariate analysis. Gene set enrichment analysis (GSEA) was performed based on the TCGA dataset. Finally, we explore the relationship between TMEM200A expression and cancer immune infiltrates using CIBERSORT.

Results

TMEM200A was up-regulated in GC tissues than that in adjacent non-tumor tissues based on TCGA database. Meta-analysis and RT-qPCR validated the difference in TMEM200A expression. Kaplan-Meier curves suggested the increased TMEM200A had a poor prognosis in GC patients. The chi-square test and logistic regression analyses showed that the TMEM200A expression correlates significantly with T stage. Multivariate analysis showed that TMEM200A expression might be an important independent predictor of poor overall survival in GC patients. GSEA identified five immune-related signaling pathways and five tumor-related signaling pathways significantly enriched in the high TMEM200A expression phenotype pathway. Finally, we found CD8+ T cells is apparently decreased in high TMEM200A expression group. Conversely, eosinophils is increased in high expression group compared with low expression group.

Conclusion

TMEM200A is a potential prognostic biomarker and correlated with immune infiltrates in GC.

Tmem45b is essential for inflammation- and tissue injury-induced mechanical pain hypersensitivity

Persistent mechanical pain hypersensitivity associated with peripheral inflammation, surgery, trauma, and nerve injury impairs patients' quality of life and daily activity. However, the molecular mechanism and treatment are not yet fully understood. Herein, we show that chemical ablation of isolectin B4-binding (IB4⁺) afferents by IB4-saporin injection into sciatic nerves completely and selectively inhibited inflammation- and tissue injury-induced mechanical pain hypersensitivity while thermal and mechanical pain hypersensitivities were normal following nerve injury. To determine the molecular mechanism involving the specific types of mechanical pain hypersensitivity, we compared gene expression profiles between IB4⁺ neuron-ablated and control dorsal root ganglion (DRG) neurons. We identified Tmem45b as one of 12 candidate genes that were specific to somatosensory ganglia and down-regulated by IB4⁺ neuronal ablation. Indeed, Tmem45b was expressed predominantly in IB4⁺ DRG neurons, where it was selectively localized in the trans Golgi apparatus of DRG neurons but not detectable in the peripheral and central branches of DRG axons. Tmem45b expression was barely detected in the spinal cord and brain. Although Tmem45b-knockout mice showed normal responses to noxious heat and noxious mechanical stimuli under normal conditions, mechanical pain hypersensitivity was selectively impaired after inflammation and tissue incision, reproducing the pain phenotype of IB4⁺ sensory neuron-ablated mice. Furthermore, acute knockdown by intrathecal injection of Tmem45b small interfering RNA, either before or after inflammation induction, successfully reduced mechanical pain hypersensitivity. Thus, our study demonstrates that Tmem45b is essential for inflammation- and tissue injury-induced mechanical pain hypersensitivity and highlights Tmem45b as a therapeutic target for future treatment.

TMEΜ45B Interacts with Sindbis Virus Nsp1 and Nsp4 and Inhibits Viral Replication

Alphavirus infection induces the expression of type I interferons, which inhibit the viral replication by upregulating the expression of interferon-stimulated genes (ISGs). Identification and mechanistic studies of the antiviral ISGs help to better understand how the host controls viral infection and help to better understand the viral replication process. Here, we report that the ISG product TMEM45B inhibits the replication of Sindbis virus (SINV). TMEM45B is a transmembrane protein that was detected mainly in the trans-Golgi network, endosomes, and lysosomes but not obviously at the plasma membrane or endoplasmic reticulum. TMEM45B interacted with the viral nonstructural proteins Nsp1 and Nsp4 and inhibited the translation and promoted the degradation of SINV RNA. TMEM45B overexpression rendered the intracellular membrane-associated viral RNA sensitive to RNase treatment. In line with these results, the formation of cytopathic vacuoles (CPVs) was dramatically diminished in TMEM45B-expressing cells. TMEM45B also interacted with Nsp1 and Nsp4 of chikungunya virus (CHIKV), suggesting that it may also inhibit the replication of other alphaviruses. These findings identified TMEM45B as an antiviral factor against alphaviruses and help to better understand the process of the viral genome replication. IMPORTANCE Alphaviruses are positive-stranded RNA viruses with more than 30 members. Infection with Old World alphaviruses, which comprise some important human pathogens such as chikungunya virus and Ross River virus, rarely results in fatal diseases but can lead to high morbidity in humans. Infection with New World alphaviruses usually causes serious encephalitis but low morbidity in humans. Alphavirus infection induces the expression of type I interferons, which subsequently upregulate hundreds of interferon-stimulated genes. Identification and characterization of host antiviral factors help to better understand how the viruses can establish effective infection. Here, we identified TMEM45B as a novel interferon-stimulated antiviral factor against Sindbis virus, a prototype alphavirus. TMEM45B interacted with viral proteins Nsp1 and Nsp4, interfered with the interaction between Nsp1 and Nsp4, and inhibited the viral replication. These findings provide insights into the detailed process of the viral replication and help to better understand the virus-host interactions.

Targeting TMEM88 as an Attractive Therapeutic Strategy in Malignant Tumors

According to authoritative surveys, the overall morbidity and mortality of malignant tumors show an upward trend, and it is predicted that this trend will not be well contained in the upcoming new period. Since the influencing factors, pathogenesis, and progression characteristics of malignant tumors have not been fully elucidated, the existing treatment strategies, mainly including surgical resection, ablation therapy and chemotherapy, cannot achieve satisfactory results. Therefore, exploring potential therapeutic targets and clarifying their functions and mechanisms in continuous research and practice will provide new ideas and possibilities for the treatment of malignant tumors. Recently, a double-transmembrane protein named transmembrane protein 88 (TMEM88) was reported to regulate changes in downstream effectors by mediating different signaling pathways and was confirmed to be widely involved in cell proliferation, differentiation, apoptosis and tumor progression. At present, abnormal changes in TMEM88 have been found in breast cancer, ovarian cancer, lung cancer, thyroid cancer and other malignant tumors, which has also attracted the attention of tumor research and attempted to clarify its function and mechanism. However, due to the lack of systematic generalization, comprehensive and detailed research results have not been comprehensively summarized. In view of this, this article will describe in detail the changes in TMEM88 in the occurrence and development of malignant tumors, comprehensively summarize the corresponding molecular mechanisms, and explore the potential of targeting TMEM88 in the treatment of malignant tumors to provide valuable candidate targets and promising intervention strategies for the diagnosis and cure of malignant tumors.

Downregulation of the Proton-Activated Cl- Channel TMEM206 Inhibits Malignant Properties of Human Osteosarcoma Cells

Transmembrane protein 206 (TMEM206), a proton-activated chloride channel, has been implicated in various biochemical processes, including bone metabolism, and has emerged as a novel cancer-related protein in multiple tumor types. However, its role in primary malignant bone tumors, particularly in osteosarcoma (OS), remains unclear. This study is aimed at exploring the effects of TMEM206 gene silencing on the proliferation, migration, invasion, and metastasis of human OS cells in vitro and in vivo using an shRNA-knockdown strategy. We found that TMEM206 is frequently overexpressed and that high levels of TMEM206 correlated with clinical stage and pulmonary metastasis in patients with OS. We provided evidence that TMEM206-silenced OS cancer cells exhibit decreased proliferation, migration, and invasion in vitro. Mechanistically, we identified β-catenin, a key member of Wnt/β-catenin signaling, as a downstream effector of TMEM206. TMEM206 silencing inhibits the Wnt/β-catenin signaling pathway in expression rescue experiments, confirming that TMEM206 silencing attenuates OS cell tumorigenic behavior, at least in part, via the β-catenin mediated downregulation of Wnt/β-catenin signaling. More importantly, TMEM206 knockdown-related phenotype changes were replicated in a xenograft nude mouse model where pulmonary metastases of OS cells were suppressed. Together, our results demonstrate that silencing TMEM206 negatively modulates the Wnt/β-catenin signaling pathway via β-catenin to suppress proliferation, migration, invasion, and metastasis in OS carcinogenesis, suggesting TMEM206 as a potential oncogenic biomarker and a potential target for OS treatment.

P7TP3 inhibits tumor development, migration, invasion and adhesion of liver cancer through the Wnt/β-catenin signaling pathway

The effect of hepatitis C virus p7 trans‐regulated protein 3 (P7TP3) in the development of hepatocellular carcinoma (HCC) is still unknown. The present study aimed to investigate the role and mechanism of P7TP3 in HCC. P7TP3 was significantly decreased in HCC tissues when compared with corresponding liver tissues immediately around the tumor (LAT) from seven HCC patients. Fewer and smaller colonies originated from HepG2‐P7TP3 cells when compared to HepG2‐NC cells. Overexpression of P7TP3 in HepG2 cells significantly repressed the growth of HCC xenografts in nude mice. Furthermore, wound‐healing tests, Transwell assays, Matrigel Transwell assays, adhesion assays, CCK‐8 assays, flow cytometry and western blotting analysis showed that P7TP3 protein expression inhibited migration, invasion, adhesion, proliferation and cell cycle progression in HCC cell lines. Moreover, P7TP3 suppressed the activity of the Wnt/β‐catenin signaling pathway, and was restored by Wnt3a, which is an activator of the Wnt/β‐catenin signaling pathway. Consistently, β‐catenin was highly expressed by P7TP3 silencing, and restored by XAV939, an inhibitor of the Wnt/β‐catenin signaling pathway. Finally, microRNA (miR)‐182‐5p suppressed the expression of target gene P7TP3 by directly interacting with the 3′‐UTR region. Taken together, P7TP3, the direct target gene of miR‐182‐5p, inhibited HCC by regulating migration, invasion, adhesion, proliferation and cell cycle progression of liver cancer cell through the Wnt/β‐catenin signaling pathway. These findings provide strong evidence that P7TP3 functions as a new promising tumor suppressor in HCC.

Transmembrane (TMEM) protein family members: Poorly characterized even if essential for the metastatic process

The majority of cancer-associated deaths are related to secondary tumor formation. This multistep process involves the migration of cancer cells to anatomically distant organs. Metastasis formation relies on cancer cell dissemination and survival in the circulatory system, as well as adaptation to the new tissue notably through genetic and/or epigenetic alterations. A large number of proteins are clearly identified to play a role in the metastatic process but the structures and modes of action of these proteins are essentially unknown or poorly described. In this review, we detail the involvement of members of the transmembrane (TMEM) protein family in the formation of metastases or in the mechanisms leading to cancer cell dissemination such as migration and extra-cellular matrix remodelling. While the phenotype associated with TMEM over or down-expression is clear, the mechanisms by which these proteins allow cancer cell spreading remain, for most of them, unclear. In parallel, the 3D structures of these proteins are presented. Moreover, we proposed that TMEM proteins could be used as prognostic markers in different types of cancers and could represent potential targets for cancer treatment. A better understanding of this heterogeneous family of poorly characterized proteins thus opens perspectives for better cancer patient care.

TMEM Proteins in Cancer: A Review

A transmembrane protein (TMEM) is a type of protein that spans biological membranes. Many of them extend through the lipid bilayer of the plasma membrane but others are located to the membrane of organelles. The TMEM family gathers proteins of mostly unknown functions. Many studies showed that TMEM expression can be down- or up-regulated in tumor tissues compared to adjacent healthy tissues. Indeed, some TMEMs such as TMEM48 or TMEM97 are defined as potential prognostic biomarkers for lung cancer. Furthermore, experimental evidence suggests that TMEM proteins can be described as tumor suppressors or oncogenes. TMEMs, such as TMEM45A and TMEM205, have also been implicated in tumor progression and invasion but also in chemoresistance. Thus, a better characterization of these proteins could help to better understand their implication in cancer and to allow the development of improved therapy strategies in the future. This review gives an overview of the implication of TMEM proteins in cancer.

Long noncoding RNA HOXD-AS1 aggravates osteosarcoma carcinogenesis through epigenetically inhibiting p57 via EZH2

Osteosarcoma is the most common primary malignant bone tumor and long non-coding RNAs (lncRNAs) have been proved to epigenetically regulate the oncogenesis of osteosarcoma. In this research, we investigate the role of lncRNA HOXD-AS1 on the osteosarcoma oncogenesis. Results revealed that HOXD-AS1 expression level was significantly up-regulated in osteosarcoma tissue and cells, moreover, the aberrant overexpression predicted the poor prognosis of osteosarcoma patients. Loss-of-functional experiments indicated that HOXD-AS1 silencing inhibited the osteosarcoma cells proliferation and induced G1/G0 phase arrest in vitro, and repressed tumor cell growth in vivo. Mechanistic investigations showed that HOXD-AS1 epigenetically repressed p57 through recruiting enhancer of zeste homolog 2 (EZH2) to the promoter of p57. Rescue experiments revealed that p57 could recover the oncogenic role of HOXD-AS1 on osteosarcoma. In conclusion, our study confirmed that HOXD-AS1 could interact with EZH2, and then repress p57 expression, to aggravate osteosarcoma oncogenesis. which provide new idea for the osteosarcoma tumorigenesis.