Inhibition of TMEM45A suppresses proliferation, induces cell cycle arrest and reduces cell invasion in human ovarian cancer cells

TMEM44 as a Novel Prognostic Marker for Kidney Renal Clear Cell Carcinoma is Associated with Tumor Invasion, Migration and Immune Infiltration

Transmembrane (TMEM) proteins are integral membrane proteins that traverse biological membranes. Several members of the TMEM family have been linked to the development and progression of various tumors. However, the specific role and mechanism of TMEM44 in tumor biology remain largely unexplored. In this study, we initially conducted an extensive analysis using the TCGA database to investigate the expression patterns and survival associations of TMEM44 across various human tumors. Subsequently, we focused on KIRC and found a significant correlation between TMEM44 expression and this particular cancer type. To validate our findings, we performed western blot and quantitative polymerase chain reaction (qPCR) assays to confirm the expression levels of TMEM44 in KIRC. Following this, we employed a series of functional assays, including CCK8 viability assay, EDU incorporation assay, wound healing assay, and transwell migration assay, to investigate the biological role of TMEM44 in KIRC. We observed a significant upregulation of TMEM44 expression in KIRC, indicating its potential involvement in the pathogenesis of this cancer. We intervened in the expression of TMEM44 in KIRC cells and found significant inhibitory effects on cell proliferation, migration, and invasion in KIRC cells. Furthermore, our findings indicated that TMEM44 could serve as an independent prognostic factor in KIRC, highlighting its potential clinical significance. Consequently, TMEM44 holds promise as both a prognostic biomarker and a prospective therapeutic target for KIRC.

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.

Illustrating the biological functions and diagnostic value of transmembrane protein family members in glioma

Background

It is well-established that patients with glioma have a poor prognosis. Although the past few decades have witnessed unprecedented medical advances, the 5-year survival remains dismally low.

Objective

This study aims to investigate the role of transmembrane protein-related genes in the development and prognosis of glioma and provide new insights into the pathogenesis of the disease

Methods

The datasets of glioma patients, including RNA sequencing data and relative clinical information, were obtained from The Cancer Genome Atlas (TCGA), Chinese Glioma Genome Atlas (CGGA) and Gene Expression Omnibus (GEO) databases. Prognostic transmembrane protein-related genes were identified by univariate Cox analysis. New disease subtypes were recognized based on the consensus clustering method, and their biological uniqueness was verified via various algorithms. The prognosis signature was constructed using the LASSO-Cox regression model, and its predictive power was validated in external datasets by receiver operating characteristic (ROC) curve analysis. An independent prognostic analysis was conducted to evaluate whether the signature could be considered a prognostic factor independent of other variables. A nomogram was constructed in conjunction with traditional clinical variables. The concordance index (C-index) and Decision Curve Analysis (DCA) were used to assess the net clinical benefit of the signature over traditional clinical variables. Seven different softwares were used to compare the differences in immune infiltration between the high- and low-risk groups to explore potential mechanisms of glioma development and prognosis. Hub genes were found using the random forest method, and their expression was based on multiple single-cell datasets.

Results

Four molecular subtypes were identified, among which the C1 group had the worst prognosis. Principal Component Analysis (PCA) results and heatmaps indicated that prognosis-related transmembrane protein genes exhibited differential expression in all four groups. Besides, the microenvironment of the four groups exhibited significant heterogeneity. The 6 gene-based signatures could predict the 1-, 2-, and 3-year overall survival (OS) of glioma patients. The signature could be used as an independent prognosis factor of glioma OS and was superior to traditional clinical variables. More immune cells were infiltrated in the high-risk group, suggesting immune escape. According to our signature, many genes were associated with the content of immune cells, which revealed that transmembrane protein-related genes might influence the development and prognosis of glioma by regulating the immune microenvironment. TMEM158 was identified as the most important gene using the random forest method. The single-cell datasets consistently showed that TMEM158 was expressed in multiple malignant cells.

Conclusion

The expression of transmembrane protein-related genes is closely related to the immune status and prognosis of glioma patients by regulating tumor progression in various ways. The interaction between transmembrane protein-related genes and immunity during glioma development lays the groundwork for future studies on the molecular mechanism and targeted therapy of glioma.

TMEM196 inhibits lung cancer metastasis by regulating the Wnt/β-catenin signaling pathway

PURPOSE

The TMEM196 protein, which comprises four membrane-spanning domains, belongs to the TMEM protein family. TMEM196 was identified as a candidate tumor suppressor gene in lung cancer. However, its role and mechanism in lung cancer metastasis remain unclear. Here, we study the role of TMEM196 in tumor metastasis to further verify the function in lung cancer.

METHODS

In this study, we used qRT-PCR, western blot analysis and immunohistochemistry to examine the expression levels of TMEM196 and related proteins in lung cancer tissues and tumor cells. We utilized Transwell assays, xenograft nude mouse models, and TMEM196^-/- mouse models to evaluate the effects of TMEM196 on tumor invasion and metastasis. Finally, we used bioinformatics analysis and dual-luciferase reporter gene assays to explore the molecular mechanism of TMEM196 as a tumor suppressor.

RESULTS

We found that TMEM196 mRNA and protein expression levels were significantly decreased in lung cancer tissues and cells. Low expression of TMEM196 in clinical patients was associated with poor prognosis. TMEM196 strongly inhibited tumor metastasis and progression in vitro and in vivo. The primary lung tumors induced by tail vein-inoculated B16 cells in TMEM196^-/- mice were significantly larger than those in TMEM196^+/+ mice. Mechanistically, TMEM196 inhibited the Wnt signaling pathway and repressed β-catenin promoter transcription. TMEM196 silencing in lung cancer cells and mice resulted in significant upregulation of the expression of β-catenin and Wnt signaling pathway downstream target genes (MMP2 and MMP7). Decreasing β-catenin expression in TMEM196-silenced cancer cells attenuated the antimetastatic effect of TMEM196.

CONCLUSIONS

Our results revealed that TMEM196 acts as a novel lung cancer metastasis suppressor via the Wnt/β-catenin signaling pathway.

Analysis of the Single-Cell Heterogeneity of Adenocarcinoma Cell Lines and the Investigation of Intratumor Heterogeneity Reveals the Expression of Transmembrane Protein 45A (TMEM45A) in Lung Adenocarcinoma Cancer Patients

Simple Summary

Non-small cell lung cancer (NSCLC) is one of the main causes of cancer-related deaths worldwide. Intratumoral heterogeneity (ITH) is responsible for the majority of difficulties encountered in the treatment of lung-cancer patients. Therefore, the heterogeneity of NSCLC cell lines and primary lung adenocarcinoma was investigated by single-cell mass cytometry (CyTOF). Human NSCLC adenocarcinoma cells A549, H1975, and H1650 were studied at single-cell resolution for the expression pattern of 13 markers: GLUT1, MCT4, CA9, TMEM45A, CD66, CD274, CD24, CD326, pan-keratin, TRA-1-60, galectin-3, galectin-1, and EGFR. The intra- and inter-cell-line heterogeneity of A549, H1975, and H1650 cells were demonstrated through hypoxic modeling. Additionally, human primary lung adenocarcinoma, and non-involved healthy lung tissue were homogenized to prepare a single-cell suspension for CyTOF analysis. The single-cell heterogeneity was confirmed using unsupervised viSNE and FlowSOM analysis. Our results also show, for the first time, that TMEM45A is expressed in lung adenocarcinoma.

Abstract

Intratumoral heterogeneity (ITH) is responsible for the majority of difficulties encountered in the treatment of lung-cancer patients. Therefore, the heterogeneity of NSCLC cell lines and primary lung adenocarcinoma was investigated by single-cell mass cytometry (CyTOF). First, we studied the single-cell heterogeneity of frequent NSCLC adenocarcinoma models, such as A549, H1975, and H1650. The intra- and inter-cell-line single-cell heterogeneity is represented in the expression patterns of 13 markers—namely GLUT1, MCT4, CA9, TMEM45A, CD66, CD274 (PD-L1), CD24, CD326 (EpCAM), pan-keratin, TRA-1-60, galectin-3, galectin-1, and EGFR. The qRT-PCR and CyTOF analyses revealed that a hypoxic microenvironment and altered metabolism may influence cell-line heterogeneity. Additionally, human primary lung adenocarcinoma and non-involved healthy lung tissue biopsies were homogenized to prepare a single-cell suspension for CyTOF analysis. The CyTOF showed the ITH of human primary lung adenocarcinoma for 14 markers; particularly, the higher expressions of GLUT1, MCT4, CA9, TMEM45A, and CD66 were associated with the lung-tumor tissue. Our single-cell results are the first to demonstrate TMEM45A expression in human lung adenocarcinoma, which was verified by immunohistochemistry.

Identification and clinical validation of EMT-associated prognostic features based on hepatocellular carcinoma

BACKGROUND

The aim of this study was to construct a model based on the prognostic features associated with epithelial-mesenchymal transition (EMT) to explore the various mechanisms and therapeutic strategies available for the treatment of metastasis and invasion by hepatocellular carcinoma (HCC) cells.

METHODS

EMT-associated genes were identified, and their molecular subtypes were determined by consistent clustering analysis. The differentially expressed genes (DEGs) among the molecular subtypes were ascertained using the limma package and they were subjected to functional enrichment analysis. The immune cell scores of the molecular subtypes were evaluated using ESTIMATE, MCPcounter, and GSCA packages of R. A multi-gene prognostic model was constructed using lasso regression, and the immunotherapeutic effects of the model were analyzed using the Imvigor210 cohort. In addition, immunohistochemical analysis was performed on a cohort of HCC tissue to validate gene expression.

RESULTS

Based on the 59 EMT-associated genes identified, the 365-liver hepatocellular carcinoma (LIHC) samples were divided into two subtypes, C1 and C2. The C1 subtype mostly showed poor prognosis, had higher immune scores compared to the C2 subtype, and showed greater correlation with pathways of tumor progression. A four-gene signature construct was fabricated based on the 1130 DEGs among the subtypes. The construct was highly robust and showed stable predictive efficacy when validated using datasets from different platforms (HCCDB18 and GSE14520). Additionally, compared to currently existing models, our model demonstrated better performance. The results of the immunotherapy cohort showed that patients in the low-risk group have a better immune response, leading to a better patient's prognosis. Immunohistochemical analysis revealed that the expression levels of the FTCD, PON1, and TMEM45A were significantly over-expressed in 41 normal samples compared to HCC samples, while that of the G6PD was significantly over-expressed in cancerous tissues.

CONCLUSIONS

The four-gene signature construct fabricated based on the EMT-associated genes provides valuable information to further study the pathogenesis and clinical management of HCC.

Transmembrane protein 45A regulates the proliferation, migration, and invasion of glioma cells through nuclear factor kappa-B

Gliomas are the most common and aggressive type of primary brain cancer in adults. The expression of transmembrane protein 45A (TMEM45A) in glioma patients and glioma cell lines was analyzed by quantitative real-time PCR. The influence of TMEM45A on the survival of glioma patients was also explored in this study. To verify the interaction between TMEM45A and key genes, correlation analysis of expression levels and the siRNA knock down method were performed. TMEM45A was upregulated in glioma tissues, and its overexpression was strongly correlated with the poor survival of glioma patients. Experiments using the overexpression and knock down of TMEM45A were carried out to demonstrate its correlation with enhanced proliferation, migration, and invasion in glioma cells. Nuclear factor kappa-B (NFκB) expression was shown to be a downstream factor of TMEM45A in glioma cells. In conclusion, TMEM45A is an oncogenic gene in glioma. The proliferation, migration, and invasion of gliomas could be effectively impeded by inhibition of TMEM45A, and the cancer-promoting effect of TMEM45A on gliomas was involved with the NFκB pathway.

TMEM45A Affects Proliferation, Apoptosis, Epithelial-Mesenchymal Transition, Migration, Invasion and Cisplatin Resistance of HPV-Positive Cervical Cancer Cell Lines

To investigate the effects of transmembrane protein 45A (TMEM45A) on biological characteristics and cisplatin (DDP) resistance of cervical cancer cells. TMEM45A in cervical cancer cells and normal cervical epithelial cells (HCerEpiC) were quantified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. HPV genotypes were identified by multiplex PCR. SiHa and HeLa cells were divided into Blank, shCTL, shTMEM45A-1, and shTMEM45A-2 groups, followed by Cell Counting Kit-8 (CCK-8), EdU, Annexin V-FITC/PI staining, Wound healing, and Transwell invasion assays, as well as qRT-PCR and Western blotting. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) was employed to evaluate the impact of TMEM45A shRNA on cisplatin-resistant cervical cancer cells (SiHa/DDP and HeLa/DDP). Compared with HcerEpic cell, cervical cancer cells exhibited the upregulation of TMEM45A expression, especially in HPV-positive cell lines (CaSki, SiHa, HeLa). TMEM45A shRNA suppressed the proliferation of SiHa and HeLa cells, arrested cells at the S phase, and promoted cell apoptosis. TMEM45A shRNA inhibited the epithelial-mesenchymal transition (EMT), invasion, migration of SiHa and HeLa cells, accompanying by the downregulated Vimentin and N-cadherin with the upregulated E-cadherin. Moreover, SiHa/DDP and HeLa/DDP had higher TMEM45A expression than their parental SiHa and HeLa cells, respectively. And inhibiting TMEM45A can reduce the IC50 of SiHa/DDP cells and HeLa/DDP cells to cisplatin. Silencing TMEM45A can inhibit cell proliferation, invasion, migration and EMT, regulate cell cycle distribution, promote cell apoptosis, and reverse cisplatin resistance of HPV-positive cervical cancer cells, highlighting that inhibition of TMEM45A may be a therapeutic strategy for HPV-positive cervical cancer.

Overexpression of TMEM47 Induces Tamoxifen Resistance in Human Breast Cancer Cells

Background:

Tamoxifen (TAM) is the eminent first-line drug for endocrine therapy of hormone receptor positive premenopausal breast cancer and reduces the risk of recurrence by ∼50%. However, many patients developed TAM resistance and their diseases recurred. Our previous study on transcriptome profile of TAM resistant breast cancer cells revealed that the TMEM47 is one of the most significantly differentially expressed genes. The mechanism of how TMEM47 is involved in TAM resistance was not known.

Methods:

We constructed a mammal breast cancer cell line, in which TMEM47 was stably overexpressed (TMEM47-OE/MCF-7), to further verify the role of TMEM47 in TAM resistance. siRNA targeting TMEM47 was transfected into TAMR / MCF-7 cells by Liposome. TMEM47 expression was validated on mRNA and protein level by qRT-PCR and western blotting. We tested the cytotoxicity of TAM in the cells. Apoptosis was detected by flow cytometry.

Results:

Compared to the MCF7 cells, TMEM47 mRNA was significantly up regulated more than 6 folds in the TAMR/MCF7 cells and so its protein. TMEM47 expression level in TMEM47-OE/MCF-7 was similar as in the TAMR/MCF-7 cells. The 50% inhibitory concentration (IC50) value (mean ± SD) of TAM in MCF-7, TAMR/MCF-7 and TMEM47-OE/MCF-7 cells was 1.58 ± 0.19, 2.74 ± 0.24 and 3.12 ± 0.32 µγ/mL, respectively. The apoptosis rates of TAMR/MCF-7 and TMEM47-OE/MCF-7 cell lines were significantly lower than that of MCF-7 cells. After 24 and 48 hours TAM treatments, cell viability was significantly inhibitied in TMEM47 knockdown TAMR/MCF7 cells (P < 0.01). Consistant with the decreased cell viability, the apoptosis rate in TMEM47 knockdown TAMR/MCF-7 cells was significantly increased.

Conclusions:

Our results suggest that overexpression of TMEM47 in MCF-7 cells acquired TAM resistance to those cells, and knockdown of TMEM47 in TAMR/MCF-7 cells reversed their resistance to TAM. TMEM47 might confer TAM resistance on MCF-7 cells through the inhibition of apoptosis.

TMEM119 facilitates ovarian cancer cell proliferation, invasion, and migration via the PDGFRB/PI3K/AKT signaling pathway

Background

Ovarian cancer (OV) is the deadliest gynecological cancer. Transmembrane protein 119 (TMEM119) has been reported as oncogene in several human cancers. However, the function of TMEM119 in OV is still poorly known.

Methods

Western blot and qRT-PCR were used to analyze TMEM119 levels. Transwell assays, wound healing assays, CCK-8 assays and EdU cell proliferation assays were designed to explore the function and potential mechanism of TMEM119 in malignant biological behaviors in OV.

Results

TMEM119 was observed to be overexpressed in OV tissues and associated with poor survival in OV patients. Knockdown and overexpression experiments demonstrated that TMEM119 promoted proliferation, invasion, and migration in OV cells in vitro. TMEM119 mRNA expression was related to the pathways of focal adhesion according to Gene Set Enrichment Analyses and was correlated with the mRNA expression level of platelet-derived growth factor receptor beta (PDGFRB). TMEM119 exerted oncogenic effects partially by regulating the expression of PDGFRB and by activating the PI3K/AKT signaling pathway.

Conclusions

Collectively, our findings highlight the potential role of TMEM119 in the malignant biological behavior of OV, which may serve as a potential biomarker and a therapeutic candidate for OV.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02781-x.

TMEM106C contributes to the malignant characteristics and poor prognosis of hepatocellular carcinoma

Transmembrane protein (TMEM) is a kind of integral membrane protein that spans biological membranes. The functions of most members of the TMEM family are unknown. Here, we conducted bioinformatic analysis and biological validation to investigate the role of TMEM106C in HCC. First, GEPIA and Oncomine^TM were used to analyze TMEM106C expression, which was verified by real-time PCR and western blot analyses. Then, the biological functions of TMEM106C were explored by CCK8 and transwell assays. The prognostic value of TMEM106C was analyzed by UALCAN. LinkedOmics was used to analyze TMEM106C pathways generated by Gene Ontology. A protein-protein interaction network (PPI) was constructed by GeneMANIA. We demonstrated that TMEM106C was overexpressed in HCC and that inhibition of TMEM106C significantly suppressed the proliferation and metastasis of HCC through targeting CENPM and DLC-1. Upregulation of TMEM106C was closely correlated with sex, tumor stage, tumor grade and prognosis. Overexpression of TMEM106C was linked to functional networks involving organelle fission and cell cycle signaling pathways through the regulation of CDK kinases, E2F1 transcription factors and miRNAs. Our data demonstrated that TMEM106C contributes to malignant characteristics and poor prognosis in HCC, which may serve as a prognostic biomarker and potential therapeutic target.

Therapeutic Implications of TGFβ in Cancer Treatment: A Systematic Review

Transforming growth factor β (TGFβ) is a pleiotropic cytokine that participates in a wide range of biological functions. The alterations in the expression levels of this factor, or the deregulation of its signaling cascade, can lead to different pathologies, including cancer. A great variety of therapeutic strategies targeting TGFβ, or the members included in its signaling pathway, are currently being researched in cancer treatment. However, the dual role of TGFβ, as a tumor suppressor or a tumor-promoter, together with its crosstalk with other signaling pathways, has hampered the development of safe and effective treatments aimed at halting the cancer progression. This systematic literature review aims to provide insight into the different approaches available to regulate TGFβ and/or the molecules involved in its synthesis, activation, or signaling, as a cancer treatment. The therapeutic strategies most commonly investigated include antisense oligonucleotides, which prevent TGFβ synthesis, to molecules that block the interaction between TGFβ and its signaling receptors, together with inhibitors of the TGFβ signaling cascade-effectors. The effectiveness and possible complications of the different potential therapies available are also discussed.

Upregulation of TMEM45A Promoted the Progression of Clear Cell Renal Cell Carcinoma in vitro

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is the most common and aggressive type of primary kidney cancer worldwide. Transmembrane protein 45A (TMEM45A) has been reported to be closely associated with the progression of several cancers. However, the role of TMEM45A in ccRCC remains unclear. Our study intended to explore the potential role of TMEM45A in ccRCC.

METHODS

Data on the expression of TMEM45A were obtained from multiple databases, including UCSC, GEPIA2, Oncomine and TIMER. Real-world samples of ccRCC and paired normal renal tissues were used to confirm the information obtained from the databases. In addition, the prognostic value of TMEM45A was evaluated. Loss-of-function assays were performed using TMEM45A-targeting lentivirus to evaluate the biological role of TMEM45A in renal cancer cells. Gene set enrichment analysis (GSEA) was performed to investigate the potential molecular mechanisms.

RESULTS

TMEM45A was significantly overexpressed in patients with ccRCC and correlated with poor overall survival and disease-free survival. In addition, the expression of TMEM45A was closely associated with various clinicopathological parameters such as histological grade and TNM stage. Knockdown of TMEM45A inhibited the proliferation and migration and promoted the apoptosis of ccRCC cells in vitro. The results of the GSEA suggested that TMEM45A was potentially involved in the promotion of epithelial-mesenchymal transition (EMT) and inflammatory response in ccRCC.

CONCLUSION

TMEM45A was overexpressed and associated with poor survival and acted as a tumour promoter in ccRCC; therefore, might be a potential prognostic marker and therapeutic target.

TMEM206 is a potential prognostic marker of hepatocellular carcinoma

Transmembrane proteins are involved in the transportation of materials into and out of cells. The transmembrane protein (TMEM) family is a collection of poorly described transmembrane proteins that serve important roles in tumor development and progression. A number of TMEM proteins have been discovered. A newly discovered TMEM protein, TMEM206, transports ions across the membrane under physiological and pathological conditions, generating an acidic environment, which serves an important role in the microenvironment. However, the prognostic value and regulatory mechanisms of action of TMEM206 in tumors is unclear. The aim of the present study was to evaluate the prognostic value and regulation mechanisms of TMEM206 in tumors. Firstly, the expression of TMEM206 in tumors and normal tissues was assessed using the GEPIA and Oncomine databases and the results revealed that TMEM206 expression increased or decreased depending on the type of tumor. Subsequently, using the Human Protein Atlas and the Kaplan-Meier plotter, the findings of the present study revealed that TMEM206 is related to the prognosis of hepatocellular carcinoma. In order to explore the mechanism of TMEM206 in promoting tumor progression, GEO and cBioPortal were used to determine genes that may be co-expressed with TMEM206. MetaScape was used to identify the signaling pathways that TMEM206 may participate in. Finally, miRWalk, miRDB and TargetScan were used to identify miRNAs that may regulate the expression of TMEM206 and the findings revealed that 2 miRNA (hsa-miR-325 and hsa-miR-510-5p) were involved. In conclusion, upregulation of TMEM206 is associated with poor prognosis in patients with hepatocellular carcinoma.

Effect of preoperative chemoradiotherapy on the immunological status of rectal cancer patients

The aim of the study was to investigate the effect of chemo-radiation on the genetic and immunological status of rectal cancer patients who were treated with preoperative chemoradiotherapy (CRT). The expression of immune response-associated genes was compared between rectal cancer patients treated (n = 9) and not-treated (n = 10) with preoperative CRT using volcano plot analysis. Apoptosis and epithelial-to-mesenchymal transition (EMT) marker genes were analysed by quantitative PCR (qPCR). Other markers associated with the tumor microenvironment (TME), such as tumor-infiltrating lymphocytes (TIL) and immune checkpoint molecules, were investigated using immunohistochemistry (IHC). The clinical responses of preoperative CRT for 9 rectal cancer patients were all rated as stable disease, while the pathological tumor regression score (TRG) revealed 6 cases of grade2 and 3 cases of grade1. According to the genetic signature of colon cancers, treated tumors belonged to consensus molecular subtype (CMS)4, while not-treated tumors had signatures of CMS2 or 3. CRT-treated tumors showed significant upregulation of EMT-associated genes, such as CDH2, TGF-beta and FGF, and cancer stem cell-associated genes. Additionally, qPCR and IHC demonstrated a suppressive immunological status derived from the upregulation of inflammatory cytokines (IL-6, IL-10 and TGF-beta) and immune checkpoint genes (B7-H3 and B7-H5) and from M2-type macrophage accumulation in the tumor. The induction of EMT and immune-suppressive status in the tumor after strong CRT treatment urges the development of a novel combined therapy that restores immune-suppression and inhibits EMT, ultimately leading to distant metastasis control.

The lncRNA SLNCR Recruits the Androgen Receptor to EGR1-Bound Genes in Melanoma and Inhibits Expression of Tumor Suppressor p21

Melanoma is the deadliest form of skin cancer, affecting men more frequently and severely than women. Although recent studies suggest that differences in activity of the androgen receptor (AR) underlie the observed sex bias, little is known about AR activity in melanoma. Here we show that AR and EGR1 bind to the long non-coding RNA SLNCR and increase melanoma proliferation through coordinated transcriptional regulation of several growth-regulatory genes. ChIP-seq reveals that ligand-free AR is enriched on SLNCR-regulated melanoma genes and that AR genomic occupancy significantly overlaps with EGR1 at consensus EGR1 binding sites. We present a model in which SLNCR recruits AR to EGR1-bound genomic loci and switches EGR1-mediated transcriptional activation to repression of the tumor suppressor p21^Waf1/Cip1. Our data implicate the regulatory triad of SLNCR, AR, and EGR1 in promoting oncogenesis and may help explain why men have a higher incidence of and more rapidly progressive melanomas compared with women.

Master and servant: LINC00152 - a STAT3-induced long noncoding RNA regulates STAT3 in a positive feedback in human multiple myeloma

Background

The survival of INA-6 human multiple myeloma cells is strictly dependent upon the Interleukin-6-activated transcription factor STAT3. Although transcriptional analyses have revealed many genes regulated by STAT3, to date no protein-coding STAT3 target gene is known to mediate survival in INA-6 cells. Therefore, the aim here was to identify and analyze non-protein-coding STAT3 target genes. In addition to the oncogenic microRNA-21, we previously described five long noncoding RNAs (lncRNAs) induced by STAT3, named STAiRs. Here, we focus on STAT3-induced RNA 18 (STAiR18), an mRNA-like, long ncRNA that is duplicated in the human lineage. One STAiR18 locus is annotated as the already well described LINC00152/CYTOR, however, the other harbors the MIR4435-2HG gene and is, up to now, barely described.

Methods

CAPTURE-RNA-sequencing was used to analyze STAiR18 transcript architecture. To identify the STAiR18 and STAT3 phenotype, siRNA-based knockdowns were performed and microarrays were applied to identify their target genes. RNA-binding partners of STAiR18 were determined by Chromatin-Isolation-by-RNA-Purification (ChIRP) and subsequent sequencing. STAT3 expression in dependence of STAiR18 was investigated by immunoblots, chromatin- and RNA-immunoprecipitations.

Results

As identified by CAPTURE-RNA sequencing, a complex splice pattern originates from both STAiR18 loci, generating different transcripts. Knockdown of the most abundant STAiR18 isoforms dramatically decreased INA-6 cell vitality, suggesting a functional role in myeloma cells. Additionally, STAiR18 and STAT3 knockdowns yielded overlapping changes of transcription patterns in INA-6 cells, suggesting a close functional interplay between the two factors. Moreover, Chromatin isolation by RNA purification (ChIRP), followed by genome-wide RNA sequencing showed that STAiR18 associates specifically with the STAT3 primary transcript. Furthermore, the knockdown of STAiR18 reduced STAT3 levels on both the RNA and protein levels, suggesting a positive feedback between both molecules. Furthermore, STAiR18 knockdown changes the histone methylation status of the STAT3 locus, which explains the positive feedback and indicates that STAiR18 is an epigenetic modulator.

Conclusion

Hence, STAiR18 is an important regulator of myeloma cell survival and is strongly associated with the oncogenic function of STAT3. The close functional interplay between STAT3 and STAiR18 suggests a novel principle of regulatory interactions between long ncRNAs and signaling pathways.

Knockdown of TMEM45A overcomes multidrug resistance and epithelial-mesenchymal transition in human colorectal cancer cells through inhibition of TGF-β signalling pathway

Colorectal cancer (CRC), a leading cause of cancer death, has recently been known as the most prevalent malignancy worldwide. Although chemotherapy is an important therapeutic option for CRC patients, multidrug resistance (MDR) still remains a major cause of chemotherapy failure. Transmembrane protein 45A (TMEM45A) has been found highly expressed in various cancers, and is also proposed as an interesting biomarker for chemoresistance. However, the association between TMEM45A and MDR in CRC remains unclear. This study aimed to investigate the key role of TMEM45A in CRC by knockdown of its expression in 5-FU-resistant CRC cells (HCT-8/5-FU and SW480/5-FU) and their parental cells (HCT-8 and SW480). Data showed that TMEM45A was significantly up-regulated in HCT-8/5-FU and SW480/5-FU cells in comparison with their parental HCT-8 and SW480 cells. Knockdown of TMEM45A enhanced 5-FU sensitivity and 5-FU-induced apoptosis in HCT-8/5-FU and SW480/5-FU cells. It was also found that inhibition of TMEM45A increased the intracellular accumulation of Rhodamine-123 and down-regulated the expression of MDR1 in HCT-8/5-FU and SW480/5-FU cells. In addition, knockdown of TMEM45A suppressed migration and invasion of HCT-8/5-FU and SW480/5-FU cells. Furthermore, knockdown of TMEM45A not only attenuated MDR-enhanced epithelial-mesenchymal transition (EMT), but also suppressed MDR-enhanced activation of the TGF-β signalling pathway in HCT-8/5-FU and SW480/5-FU cells. Taken together, our study suggests that knockdown of TMEM45A can effectively overcome MDR and inhibit EMT via suppression of the TGF-β signalling pathway in human CRC cells, and that targeting TMEM45A will be a potential strategy in the treatment of MDR in CRC.

Characterization of the role of TMEM45A in cancer cell sensitivity to cisplatin

TMEM45A is a transmembrane protein involved in tumor progression and cancer resistance to chemotherapeutic agents in hypoxic condition. It is correlated to a low breast cancer patient overall survival. However, little is known about this protein, in particular the mechanisms by which TMEM45A modulates cancer cell chemosensitivity. In this work, the messenger RNA expression of TMEM45A was assessed in head and neck squamous cell carcinoma (HNSCC) and renal cell carcinoma (RCC) biopsies. TMEM45A was upregulated in patients diagnosed for head and neck or renal cancer. Then, the implication of this protein in cisplatin sensitivity was explored in SQD9 and RCC4 + pVHL cells. TMEM45A inactivation decreased cell proliferation and modulated cell responses to cisplatin. Indeed, TMEM45A inactivation increased the sensitivity of SQD9 cells to cisplatin, whereas it rendered RCC4 + pVHL cells resistant to this anticancer agent. Through RNA-sequencing analysis, we identified several deregulated pathways that indicated that the impact on cisplatin sensitivity may be associated to the inhibition of DNA damage repair and to UPR pathway activation. This study demonstrated, for the first time, an anti or a pro-apoptotic role of this protein depending on the cancer type and highlighted the role of TMEM45A in modulating patient responses to treatment.

Transmembrane Protein 39A Promotes the Replication of Encephalomyocarditis Virus via Autophagy Pathway

Encephalomyocarditis virus (EMCV) causes encephalitis, myocarditis, neuropathy, reproductive disorders, and diabetes in animals. EMCV is known to induce cell autophagy; however, the molecular mechanisms underlying this remain unclear. Here, we show that the type III-transmembrane protein, transmembrane protein 39A (TMEM39A), plays a critical role in EMCV replication. We showed that EMCV GS01 strain infection upregulated TMEM39A expression. Importantly, EMCV induced autophagy in a range of host cells. The autophagy chemical inhibitor, 3-MA, inhibited EMCV replication and reduced TMEM39A expression. This is the first study demonstrating TMEM39A promoting the replication of EMCV via autophagy. Overall, we show that TMEM39A plays a positive regulatory role in EMCV proliferation and that TMEM39A expression is dependent on the autophagy pathway.

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.

TMEM213 as a novel prognostic and predictive biomarker for patients with lung adenocarcinoma after curative resection: a study based on bioinformatics analysis

Background

Lung cancer is the leading cause of cancer-related death worldwide. Few effective biomarkers for lung adenocarcinoma have been adapted for clinical practice to assist in prognosis evaluation and treatment plan implementation. Our study's goal was to find a new biological marker associated with the prognosis of lung adenocarcinoma after curative resection and the benefit of adjuvant chemotherapy (ACT).

Methods

Using the clinical information and RNA-Seq expression from The Cancer Genome Atlas (TCGA) database, prognostic genes were screened out and analyzed by Subpopulation Treatment Effect Pattern Plot (STEPP) in GSE42127 to filter out the drug-related gene. The relationship between the gene expression and clinicopathological parameters was assessed in the TCGA database. The prognostic significance was evaluated by Cox proportional hazards (PHs) regression analysis with 1,000 bootstrap replications. Gene set enrichment analysis (GSEA) was performed using high-throughput RNA sequencing data in TCGA and functional gene sets derived from the Molecular Signatures Database (MSigDB).

Results

A total of 297 prognostic genes were analyzed by STEPP in GSE42127. The results indicated a beneficial effect of adjuvant paclitaxel-carboplatin in patients with high TMEM213 expression. Its expression correlated with gender (P=0.013), and Kaplan-Meier analysis showed that patients with high TMEM213 expression had significantly longer overall survival (OS) (P=0.014, 0.027, and 0.000). Multivariate analysis showed TMEM213 to be an independent predictor for improved OS of patients (P=0.020), and the result was verified with the bootstrapping methodology and online "Kaplan-Meier Plotter" database analysis. Moreover, enriched pathway analysis indicated that TMEM213 expression was associated with the two gene sets of KEGG_DRUG_METABOLISM_CYTOCHROME_P450 and KEGG_ABC_TRANSPORTERS.

Conclusions

Based on bioinformatics analysis, we found that TMEM213 expression independently predicted better OS for lung adenocarcinoma. Patients in the high TMEM213 group appear to benefit more from adjuvant paclitaxel-carboplatin, but this needs further validation.

CFP suppresses breast cancer cell growth by TES-mediated upregulation of the transcription factor DDIT3

Breast cancer is a heterogeneous genetic disease driven by the accumulation of individual mutations per tumor. Whole-genome sequencing approaches have identified numerous genes with recurrent mutations in primary tumors. Although mutations in well characterized tumor suppressors and oncogenes are overrepresented in these sets, the majority of the genetically altered genes have so far unknown roles in breast cancer progression. To improve the basic understanding of the complex disease breast cancer and to potentially identify novel drug targets or regulators of known cancer-driving pathways, we analyzed 86 wild-type genes and 94 mutated variants for their effect on cell growth using a serially constructed panel of MCF7 cell lines. We demonstrate in subsequent experiments that the metal cation transporter CNNM4 regulates growth by induction of apoptosis and identified a tumor suppressive role of complement factor properdin (CFP) in vitro and in vivo. CFP appears to induce the intracellular upregulation of the pro-apoptotic transcription factor DDIT3 which is associated with endoplasmic reticulum-stress response.

Retracted Article: TMEM88 inhibits fibrosis in renal proximal tubular epithelial cells by suppressing the transforming growth factor-β1/Smad signaling pathway

Transmembrane protein 88 (TMEM88) belongs to a member of the TMEM family, and was reported to be involved in fibrogenesis.

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.

TMEM119 promotes gastric cancer cell migration and invasion through STAT3 signaling pathway

Objective

TMEM119 is a member of transmembrane proteins family, which is abnormally expressed in human cancers and associated with tumorigenesis. In this study, we focused on the expression of TMEM119 and its role in cell invasion and migration in gastric cancer.

Methods

Real-time polymerase chain reaction, Western blotting, and immunohistochemistry were performed to examine the expression of TMEM119 in gastric cancer tissues and cell lines. After transfection with TMEM119 siRNA or recombined TMEM119-expressing vector, the invasion and migration ability of MKN45 and SGC-7901 cells was measured by transwell assay. The expression of TMEM119, p-STAT3, STAT3, VEGF, MMP2, and MMP9 proteins in SGC-7901 and MKN45 cells treated with TMEM119 siRNA, TMEM119-expressing vector, or AG490 was measured by Western blotting.

Results

We found that higher TMEM119 expression was found in gastric cancer tissues and cell lines and was associated with lower survival rate. TMEM119 knockdown inhibited SGC-7901 cell invasion and migration, along with the expression of p-STAT3, VEGF, MMP2, and MMP9. TMEM119 overexpression promoted MKN45 cell invasion and migration, along with the expression of p-STAT3, VEGF, MMP2, and MMP9. Additionally, AG490 treatment significantly corrected TMEM119-induced MKN45 cell migration and invasion and expression of p-STAT3, VEGF, MMP9, and MMP2 proteins.

Conclusion

The results indicated that TMEM119 promotes gastric cancer cell migration and invasion through activation of STAT3 signaling pathway, and TMEM119 may therefore act as a novel therapeutic target for gastric cancer.

TMEM17 promotes malignant progression of breast cancer via AKT/GSK3β signaling

Purpose

Current knowledge of TMEM17, a recently identified protein of the transmembrane (TMEM) family, is limited, especially with respect to its expression and biological functions in malignant tumors. This study analyzed TMEM17 expression in invasive breast cancer tissue and breast cell lines and its relevance to clinicopathological factors, and investigated the mechanisms underlying the biological effects of TMEM17 on breast cancer cells.

Patients and methods

TMEM17 protein expression was determined in 20 freshly harvested specimens (tumor and paired normal tissues) by Western blotting. Immunohistochemical analysis was performed to determine the expression and subcellular localization of TMEM17 in samples from 167 patients (mean age, 49 years) diagnosed with invasive ductal carcinoma (38 with triple-negative breast cancer; 129 with non-triple-negative breast cancer) who underwent complete resection in the First Affiliated Hospital of China Medical University between 2011 and 2013. Furthermore, TMEM17 was knocked down by small interfering RNAs in breast cancer cell lines.

Results

TMEM17 was found to be significantly upregulated in breast cancer tissues compared to the corresponding normal breast tissues by Western blotting (p=0.015). Immunohistochemical analysis revealed that TMEM was significantly upregulated in invasive breast cancer cells compared to adjacent normal breast duct glandular epithelial cells (10.78% vs 76.05%, p<0.001), and its expression was closely related to the patient’s T-stage (p=0.022), advanced TNM stages (p=0.007), and lymph node metastasis (p=0.012). After TMEM17 knockdown or overexpression in breast cancer cell lines, TMEM17 upregulated p-AKT, p-GSK3β, active β-catenin, and Snail, and downstream target proteins c-myc and cyclin D1, and downregulated E-cadherin, resulting in increased cancer cell proliferation, invasion, and migration. These effects were reversed by the AKT inhibitor LY294002.

Conclusion

Our results indicate that TMEM17 is upregulated in breast cancer tissues and can promote malignant progression of breast cancer cells by activating the AKT/GSK3β signaling pathway.

MicroRNA-139-5p Inhibits Cell Proliferation and Invasion by Targeting RHO-Associated Coiled-Coil-Containing Protein Kinase 2 in Ovarian Cancer

Increasing evidence indicates that the dysregulation of microRNAs is associated with the development and progression of various cancers. MicroRNA-139-5p (miR-139-5p) has been reported to have a tumor suppressive role in many types of cancers. The role of miR-139-5p in ovarian cancer (OC) is poorly understood. The purpose of the present study was to explore the expression of miR-139-5p and its function in OC. The results showed that miR-139-5p expression was markedly downregulated in OC tissues and cell lines. In addition, underexpression of miR-139-5p was significantly associated with FIGO stage, lymph mode metastasis, and poor overall survival of OC patients. Functional analyses indicated that overexpression of miR-139-5p significantly inhibited proliferation, colony formation, migration, and invasion of OC cells. Rho-associated coiled-coil-containing protein kinase 2 (ROCK2) was identified as a direct target of miR-139-5p using luciferase reporter assays, qualitative real-time reverse transcriptase PCR (qRT-PCR), and Western blot. In addition, ROCK2 expression was upregulated and was inversely correlated with miR-139-5p levels in OC tissues. Rescue experiments showed that overexpression of ROCK2 effectively reversed the inhibitory effect of OC cells induced by miR-139-5p. Most interestingly, in vivo studies indicated that miR-139-5p markedly suppressed the growth of tumors by repressing ROCK2 expression in nude mice. Taken together, these findings demonstrated that miR-139-5p plays an important tumor suppressor role in OC by directly binding to ROCK2, providing a novel target for the molecular treatment of OC.

Effect of polyphenols from coffee and grape on gene expression in myoblasts

Coffee and grape contain various bioactive compounds like polyphenols that may exert beneficial effects, especially antioxidant activity, on human health upon consumption. However, the molecular mechanisms through which these effects are achieved are not fully elucidated. Thus, in the present study in order to investigate these mechanisms, a whole genome expression DNA microarray analysis was carried out in myoblasts treated with polyphenols of coffee and grape pomace at concentrations that improved the redox status. Grape was composed of catechin, epicatechin, cyanidin, malvidin, delphinidin, petunidin, myrtillin, kuromanin, oenin, peonidin, quercetin, gallic acid and caftaric acid as LC-MS revealed, with a total polyphenolic content (TPC) of 648 mg of gallic acid equivalents/g of dry matter. Coffee had a TPC of 42.61 mg GAE/g coffee and was composed of 3-chlorogenic acid (16.61 mg/g), 4- and 5-chlorogenic acids (13.62 mg/g), as UHPLC-HRMS revealed. According to the results, grape polyphenols altered mainly the expression of cytoskeleton and differentiation-associated genes, while coffee compounds had a more profound effect, on the expression levels of many metabolic and antioxidant genes possibly through the nuclear factor (erythroid-derived 2) like-2 (Nrf2) pathway.

TMEM45B promotes proliferation, invasion and migration and inhibits apoptosis in pancreatic cancer cells

In the present study, we focused on the expression and biological functions of TMEM45B in pancreatic cancer tissues and cell lines. Real-time PCR and Western blotting were used to examine the expression levels of TMEM45B in pancreatic cancer tissues and cell lines. The functions of TMEM45B were evaluated using CCK-8, flow cytometry and transwell analysis. Our results showed that TMEM45B exhibited high expression in pancreatic cancer tissues and cell lines compared with the normal pancreatic tissues and cells. Using gene set enrichment analysis (GSEA), we found that TMEM45B may regulate multiple genes involved in the cell cycle and metastasis pathways. Downregulation of TMEM45B by RNA interference significantly reduced proliferation, invasion and migration of SW1990 and PANC-1 cells, accompanied by the induction of cell cycle arrest and apoptosis, whereas overexpression of TMEM45B promoted proliferation, invasion and migration of CFPAC-1 cells as well as apoptosis inhibition. Taken together, our study provides evidence that TMEM45B is an oncogene involved in the tumorigenesis of pancreatic cancer and may represent a new molecular target for pancreatic cancer treatment.

TMEM39A and Human Diseases: A Brief Review

Transmembrane Protein 39A (TMEM39A) is a member of TMEM family. The understanding about this protein is still limited. The earlier studies indicated that TMEM39A was a key mediator of autoimmune disease. TMEM39A seems to be involved in systemic lupus erythematosus and multiple sclerosis in numerous of populations. All of these works stop at insufficient information by using gene functioning methods such as: Genome-wide association studies (GWASs) and/or follow-up study. It is the fact that the less understood of TMEM39A actually is the attraction to the scientist in near future. In this review the current knowledge about TMEM39A and its possible roles in cell biology, physiology and pathology will be described.

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.

Genome-Wide Overexpression Screen Identifies Genes Able to Bypass p16-Mediated Senescence in Melanoma

Malignant melanomas often arise from nevi, which result from initial oncogene-induced hyperproliferation of melanocytes that are maintained in a CDKN2A/p16-mediated senescent state. Thus, genes that can bypass this senescence barrier are likely to contribute to melanoma development. We have performed a gain-of-function screen of 17,030 lentivirally expressed human open reading frames (ORFs) in a melanoma cell line containing an inducible p16 construct to identify such genes. Genes known to bypass p16-induced senescence arrest, including the human papilloma virus 18 E7 gene ( HPV18E7), and genes such as the p16-binding CDK6 with expected functions, as well as panel of novel genes, were identified, including high-mobility group box (HMGB) proteins. A number of these were further validated in two other models of p16-induced senescence. Tissue immunohistochemistry demonstrated higher levels of CDK6 in primary melanomas compared with normal skin and nevi. Reduction of CDK6 levels drove melanoma cells expressing functional p16 into senescence, demonstrating its contribution to bypass senescence.

Overexpression and Biological Function of Ubiquitin-Specific Protease 42 in Gastric Cancer

Ubiquitin-specific protease 42 (USP42) is a member of deubiquitinating enzymes (DUBs). The alterations of DUBs are implicated in the pathogenesis of a wide variety of tumors. However, there are few studies on the expression and biological function of USP42 in gastric cancer (GC). Here, the expression levels of USP42 were significantly higher in GC tissues than in non-tumorous tissues. USP42 expression was significantly correlated with tumor size, TNM stage, lymph node metastasis and overall survival of patients with GC. Moreover, USP42 silencing in two GC cell lines, AGS and MKN-45, notably inhibited cell proliferation, but stimulated G1 phase arrest. The proteins promoting cell cycle progression (Cyclin D1, Cyclin E1 and PCNA) were down-regulated in USP42-suppressed cells. Moreover, inhibition of USP42 in GC cells impaired cell invasion via affecting the expression of matrix metalloproteinases (MMPs) and epithelial-mesenchymal transition (EMT) regulators. In conclusion, USP42 overexpression could be a potential prognostic marker for GC, regulate the survival and invasive properties of GC, and may represent a novel therapeutic molecular target for this tumor.

Knockdown of TMEM14A expression by RNAi inhibits the proliferation and invasion of human ovarian cancer cells

Transmembrane protein 14A (TMEM14A) is a member of TMEMs. Alterations in TMEMs expression have been identified in several types of cancer, but the expression and function of TMEM14A in ovarian cancer is still unclear. Here, analysis on the expression data of the Cancer Genome Atlas (TCGA) ovarian serous cystadenocarcinoma (OV) dataset demonstrated the overexpression of TMEM14A in ovarian cancer tissues compared with normal tissues, which was consistent with our real-time PCR analysis on ovarian cancer and normal tissues collected from 30 patients. In addition, TMEM14A knockdown in two ovarian cancer cell lines, A2780 and HO-8910, reduced cell proliferation, causes cell cycle arrest and suppressed cell invasion. Moreover, silencing of TMEM14A notably repressed G1/S cell cycle transition and cell invasion via down-regulating the expression of cell cycle related proteins (Cyclin D1, Cyclin E and PCNA) and metastasis-related proteins (MMP-2 and MMP-9), respectively. TMEM14A knockdown significantly reduced the phosphorylation status of Smad2 and Smad3, downstream effectors of TGF-β signalling. In summary, these results indicate that TMEM14A has a pro-tumorigenic effect in ovarian cancer cells, suggesting an important role of this protein in ovarian cancer oncogenesis and metastasis.

Overexpression of TMEM158 contributes to ovarian carcinogenesis

Background

Transmembrane protein 158 (TMEM158) is a recently identified upregulated gene during Ras-induced senescence. Its association with various cancers has been recently reported. However, the expression and biological function of TMEM158 in ovarian cancer is still unclear. This study was aimed to elucidate the roles of TMEM158 in cell proliferation, adhesion and cell invasion of ovarian cancer cells.

Methods

We analyzed TMEM158 mRNA level in ovarian cancer tissues and adjacent no-tumorous tissues by real-time PCR. We then suppressed TMEM158 expression of ovarian cancer cells by RNA interference and examined the effects of TMEM158 knockdown on cancerous transformation of ovarian cancer cells.

Results

The RNA-sequencing data of the ovarian cancer cohort from The Cancer Genome Atlas project (TCGA) and our real-time PCR data showed that TMEM158 was overexpressed in ovarian cancer. Knockdown of TMEM158 by RNA interference in ovarian cancer cells significantly inhibited cell proliferation, which may be due to the increase of G1-phase arrest. Silencing of TMEM158 also inhibited cell adhesion, cell invasion as well as tumorigenicity in nude mice. Moreover, knockdown of TMEM158 notably repressed cell adhesion via down-regulating the expression intercellular adhesion molecule1 (ICAM1) and vascular cell adhesion molecule1 (VCAM1). Transforming Growth Factor-β (TGF-β) signaling pathway was also remarkably impaired by TMEM158 silencing.

Conclusions

Our data suggests that TMEM158 may work as an oncogene for ovarian cancer and that inhibition of TMEM158 may be a therapeutic strategy for ovarian cancer.