The influence of TXNDC5 gene on gastric cancer cell

The role and mechanism of TXNDC5 in cardio-oncology: Killing two birds with one stone?

Cardio-oncology has emerged as a new translational and clinical field owing to the growing repertory of cancer therapy. To date, there is a lack of effective pharmacological therapy to target cardiotoxicity. Cardio-oncology, which began by investigating the negative effects of cancer medicines on cardiovascular system, has since grown to include research into the similarities between cardiovascular disease (CVD) and cancer. Thioredoxin domain-containing protein 5 (TXNDC5) belongs to the protein disulfide isomerase (PDI) family. Many diseases, including CVD and cancer, improperly express TXNDC5. This review provides a comprehensive analysis of the expression patterns of TXNDC5 in diseases. It outlines the processes via which TXNDC5 contributes to the advancement of malignant diseases such as CVD and cancer. Additionally, it summarizes prospective therapeutic approaches that can be used to target TXNDC5 for the treatment of these diseases. This will offer novel perspectives for enhancing anticancer therapy and advancing cardio-oncology research and drug development.

The role and mechanism of TXNDC5 in disease progression

Thioredoxin domain containing protein-5 (TXNDC5), also known as endothelial protein-disulfide isomerase (Endo-PDI), is confined to the endoplasmic reticulum through the structural endoplasmic reticulum retention signal (KDEL), is a member of the PDI protein family and is highly expressed in the hypoxic state. TXNDC5 can regulate the rate of disulfide bond formation, isomerization and degradation of target proteins through its function as a protein disulfide isomerase (PDI), thereby altering protein conformation, activity and improving protein stability. Several studies have shown that there is a significant correlation between TXNDC5 gene polymorphisms and genetic susceptibility to inflammatory diseases such as rheumatoid, fibrosis and tumors. In this paper, we detail the expression characteristics of TXNDC5 in a variety of diseases, summarize the mechanisms by which TXNDC5 promotes malignant disease progression, and summarize potential therapeutic strategies to target TXNDC5 for disease treatment.

Protein Disulfide Isomerases Function as the Missing Link Between Diabetes and Cancer

Significance: Diabetes has long been recognized as an independent risk factor for cancer, but there is insufficient mechanistic understanding of biological mediators that bridge two disorders together. Understanding the pathogenic association between diabetes and cancer has become the focus of many studies, and findings are potentially valuable for the development of effective preventive or therapeutic strategies for both disorders. Recent Advances: A summary of literature reveals a possible connection between diabetes and cancer through the family of protein disulfide isomerase (PDI). Historical as well as the most recent findings on the structure, biochemistry, and biology of the PDI family were summarized in this review. Critical Issues: PDIs in general function as redox enzymes and protein chaperones to control the quality of proteins by correcting or otherwise eliminating misfolded proteins in conditions of oxidative stress and endoplasmic reticulum stress, respectively. However, individual members of the PDI family may contribute uniquely to the pathogenesis of diabetes and cancer. Studies of exemplary members such as protein disulfide isomerase-associated (PDIA) 1, PDIA6, and PDIA15 were reviewed to highlight their contributions in the pathogenesis of diabetes and cancer and how they can be potential links bridging the two disorders through the cross talk of signaling pathways. Future Directions: Apparently ubiquitous presence of the PDIs creates difficulties and challenges for scientific community to develop targeted therapeutics for the treatment of diabetes and cancer simultaneously. Understanding molecular contribution of individual PDI in the context of specific disease may provide some insights into the development of mechanism-based target-directed therapeutics. Antioxid. Redox Signal. 37, 1191-1205.

The role and mechanism of TXNDC5 in diseases

Thioredoxin domain-containing protein 5 (TXNDC5) is a member of the protein disulfide isomerase (PDI) family. It can promote the formation and rearrangement of disulfide bonds, ensuring proper protein folding. TXNDC5 has three Trx-like domains, which can act independently to introduce disulfide bonds rapidly and disorderly. TXNDC5 is abnormally expressed in various diseases, such as cancer, rheumatoid arthritis (RA), etc. It can protect cells from oxidative stress, promote cell proliferation, inhibit apoptosis and promote the progression of disease. Aberrant expression of TXNDC5 in different diseases suggests its role in disease diagnosis. In addition, targeting TXNDC5 in the treatment of diseases has shown promising application prospects. This article reviews the structure and function of TXNDC5 as well as its role and mechanism in cancer, RA and other diseases.

Squalene Loaded Nanoparticles Effectively Protect Hepatic AML12 Cell Lines against Oxidative and Endoplasmic Reticulum Stress in a TXNDC5-Dependent Way

Virgin olive oil, the main source of fat in the Mediterranean diet, contains a substantial amount of squalene which possesses natural antioxidant properties. Due to its highly hydrophobic nature, its bioavailability is reduced. In order to increase its delivery and potentiate its actions, squalene has been loaded into PLGA nanoparticles (NPs). The characterization of the resulting nanoparticles was assessed by electron microscopy, dynamic light scattering, zeta potential and high-performance liquid chromatography. Reactive oxygen species (ROS) generation and cell viability assays were carried out in AML12 (alpha mouse liver cell line) and a TXNDC5-deficient AML12 cell line (KO), which was generated by CRISPR/cas9 technology. According to the results, squalene was successfully encapsulated in PLGA NPs, and had rapid and efficient cellular uptake at 30 µM squalene concentration. Squalene reduced ROS in AML12, whereas ROS levels increased in KO cells and improved cell viability in both when subjected to oxidative stress by significant induction of Gpx4. Squalene enhanced cell viability in ER-induced stress by decreasing Ern1 or Eif2ak3 expressions. In conclusion, TXNDC5 shows a crucial role in regulating ER-induced stress through different signaling pathways, and squalene protects mouse hepatocytes from oxidative and endoplasmic reticulum stresses by several molecular mechanisms depending on TXNDC5.

CRISPR/Cas9‐2D Silicene Gene‐Editing Nanosystem for Remote NIR‐II‐Induced Tumor Microenvironment Reprogramming and Augmented Photonic Tumor Ablation

Photothermal therapy (PTT) is a minimally invasive and highly specific antineoplastic treatment, whereas the significant upregulation of TXNDC5 gene expression following PTT cripples the photothermal ablation efficacy through protein processing in the endoplasmic reticulum signaling pathway, as transcriptome sequencing and bioinformatics analysis revealed in this research. To tackle this crucial issue, a second near‐infrared biowindow (NIR‐II) light‐controlled CRISPR/Cas9 nanosystem (silicene‐Cas9) is constructed based on biosafe and biodegradable 2D silicene nanosheets with desirable photothermal‐conversion capability. The elaborate system enables remote NIR‐II‐induced reprogramming of tumor microenvironment for enhanced photonic tumor ablation. Moreover, this CRISPR/Cas9 delivery system is carried out to precisely and efficiently knock down TXNDC5 for reprogramming the tumor microenvironment and amplifying the photothermal performance of silicene, exhibiting high efficiency and controlled gene‐editing capacity of 47.68% and significantly improving therapeutic effect of tumor ablation without recurrence both in vitro and in vivo. This work not only provides a paradigm of improving the effectiveness of photothermal tumor therapy, but also develops a safe and efficient 2D silicene‐based nonviral vector for harnessing CRISPSR/Cas9 technology‐mediated genome editing, which further broadens the biomedical application of 2D silicene nanosheets.

LncRNA-ENST00000556926 regulates the proliferation, apoptosis and mRNA transcriptome of malignant-transformed BEAS-2B cells induced by coal tar pitch

As a byproduct of coal tar distillation, coal tar pitch (CTP) has been proven to be carcinogenic to human. However, the mechanisms of lung cancer induced by CTP are still unclear. It has been shown that long non-coding RNAs (LncRNAs) play an important role in the development of human cancers. This study aims to investigate the effect of LncRNA-ENST00000556926 on malignant-transformed human bronchial epithelial (BAES-2B) cells induced by coal tar pitch extracts (CTPE). In this study, BEAS-2B cells were treated with 2.4 μg/ml of CTPE for 72 h and then passaged; and the cells were treated 4 times in the same procedure, then passaged until passage 30 (CTPE30). Cell counting kit-8 (CCK-8) assay was used to detect cell viability, then cell cycle and apoptosis were analyzed by flow cytometry, and transcriptome sequencing analysis was used to detect differentially expressed mRNAs after interference of ENST00000556926. The results indicated that the expression of ENST00000556926 in CTPE30 group was significantly higher compared with control group. Furthermore, after interfering the expression of ENST00000556926, cell viability was inhibited, and cell cycle was arrested while apoptosis of malignant-transformed BEAS-2B cells was promoted. Moreover, a total of 159 differentially expressed mRNAs were screened out after interference of ENST00000556926, including 62 up-regulated mRNAs and 97 down-regulated mRNAs. In addition, knockdown of ENST00000556926 decreased the expression of thioredoxin domain containing 5 (TXNDC5) and FOXD1. In conclusion, LncRNA-ENST00000556926 could regulate the proliferation, apoptosis and mRNA transcriptome of malignant-transformed BEAS-2B cells induced by CTP, which may provide a novel treatment strategy for lung cancer.

Development of multi-epitope vaccine constructs for non-small cell lung cancer (NSCLC) against USA human leukocyte antigen background: an immunoinformatic approach toward future vaccine designing

OBJECTIVES

The design of peptide-based vaccines for cancer is a promising immunotherapy that can induce a cancer-specific cytotoxic response in tumor cells.

METHODS

Herein, we used the immunoinformatic approach in designing a multi-epitope vaccine targeting G-protein coupled receptor 87 (GPCR-87), cystine/glutamate transporter (SLC7A11), Immunoglobulin binding protein 1 (IGBP1), and thioredoxin domain-containing protein 5 (TXNDC5), which can potentially contribute to NSCLC. The MHC-I and MHC-II epitopes selected for the fusion construct were evaluated for their antigenic and non-allergenic natures via VaxiJen and AllerTop.

RESULTS

A total of five epitopes, four class-I (FIFYLKNIV, CRYTSVLFY, RYLKVVKPF, and RQAKIQRYK), and one class-II (NQVRGYPTLLWFRDG), having combined USA population coverage of 100%, were used to make ten possible multi-epitope fusion constructs. In these constructs, PADRE, a universal T-helper epitope, and RSO9, a TLR4 agonist, were fused as adjuvants. The molecular docking analysis revealed that two constructs were showing significant binding affinities toward HLA-A*02:01, the most prevalent HLA allele in USA. Moreover, MD simulations marked one construct as a promising therapeutic candidate.

CONCLUSION

The multi-epitope vaccine constructs designed using immunogenic, and non-allergenic peptides of NSCLS tumor-associated proteins are likely to pose significant therapeutic efficacies in cancer immunotherapy due to their high binding affinities toward HLA molecules.

Potential role of chimeric genes in pathway-related gene co-expression modules

Background

Gene fusion has epigenetic modification functions. The novel proteins encoded by gene fusion products play a role in cancer development. Therefore, a better understanding of the novel protein products may provide insights into the pathogenesis of tumors. However, the characteristics of chimeric genes are rarely studied. Here, we used weighted co-expression network analysis to investigate the biological roles and underlying mechanisms of chimeric genes.

Methods

Download the pig transcriptome data, we screened chimeric genes and parental genes from 688 sequences and 153 samples, predict their domains, and analyze their associations. We constructed a co-expression network of chimeric genes in pigs and conducted Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analysis on the generated modules using DAVID to identify key networks and modules related to chimeric genes.

Results

Our findings showed that most of the protein domains of chimeric genes were derived from fused pre-genes. Chimeric genes were enriched in modules involved in the negative regulation of cell proliferation and protein localization to centrosomes. In addition, the chimeric genes were related to the growth factor-β superfamily, which regulates cell growth and differentiation. Furthermore, in helper T cells, chimeric genes regulate the specific recognition of T cell receptors, implying that chimeric genes play a key role in the regulation pathway of T cells. Chimeric genes can produce new domains, and some chimeric genes are a key role involved in pathway-related function.

Conclusions

Most chimeric genes show binding activity. Domains of chimeric genes are derived from several combinations of parent genes. Chimeric genes play a key role in the regulation of several cellular pathways. Our findings may provide new directions to explore the roles of chimeric genes in tumors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02248-9.

Circ_0110805 Knockdown Enhances Cisplatin Sensitivity and Inhibits Gastric Cancer Progression by miR-299-3p/ENDOPDI Axis

Background

Gastric cancer is a prevalent primary stomach tumor. Cisplatin is frequently used to treat gastric cancer. However, the resistance of cisplatin in gastric cancer often occurs, which brings a heavy burden to gastric cancer treatment.

Methods

In this study, we revealed a novel underlying mechanism about cisplatin-resistant effect in gastric cancer. A Cell Counting Kit-8 (CCK-8) cell viability assay and a xenograft model were performed to evaluate the function of circRNA in the cisplatin resistance of gastric cancer.

Results

Compared with control groups, we observed that circ_0110805 was highly expressed, the mRNA and protein expression levels of ENDOPDI were dramatically upregulated, and the expression of miR-299-3p was significantly downregulated in gastric cancer cells, cisplatin-resistant gastric cancer tissues or cells. Functionally, circ_0110805 knockdown improved cisplatin sensitivity, induced cell apoptosis, whereas repressed cell viability, migration and invasion in AGS/DDP and HGC-27/DDP cells, which was reversed by miR-299-3p inhibitor. Additionally, ENDOPDI overexpression hindered the effects of miR-299-3p on cisplatin sensitivity and gastric cancer progression. Circ_0110805 knockdown enhanced cisplatin sensitivity in vivo. Mechanistically, circ_0110805 acted as a sponge of miR-299-3p and its targeted ENDOPDI.

Conclusion

We showed that circ_0110805 knockdown increased the sensitivity of gastric cancer to cisplatin, which also repressed gastric cancer progression by sponging miR-299-3p to downregulate ENDOPDI expression. It might provide a new insight for future studying cisplatin-resistant gastric cancer.

Circ_0000517 Contributes to Hepatocellular Carcinoma Progression by Upregulating TXNDC5 via Sponging miR-1296-5p

Background

Circular RNAs (circRNAs) function as essential regulators in diverse human cancers, including hepatocellular carcinoma (HCC). However, the function of circ_0000517 in HCC was unknown. We aimed to explore the roles and mechanisms of circ_0000517 in HCC.

Materials and Methods

The levels of circ_0000517, RPPH1 mRNA and microRNA-1296-5p (miR-1296-5p) were measured using quantitative real-time polymerase chain reaction (qRT-PCR). The characteristics of circ_0000517 were explored by RNase R digestion and actinomycin D assays. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8) and colony formation assays. Cell cycle process and cell apoptosis were analyzed by flow cytometry analysis. The function of circ_0000517 in vivo was explored by a murine xenograft model. The association between miR-1296-5p and circ_0000517 or thioredoxin domain containing 5 (TXNDC5) was determined by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. The protein level of TXNDC5 was detected by Western blot assay.

Results

Circ_0000517 was upregulated in HCC tissues and cells. Silencing of circ_0000517 suppressed HCC cell viability and colony formation and promoted cell cycle arrest and apoptosis in vitro and hampered tumor growth in vivo. MiR-1296-5p was a target of circ_0000517 and the effects of circ_0000517 silencing on HCC cell viability, cell cycle, colony formation and apoptosis were abolished by miR-1296-5p inhibition. TXNDC5 functioned as a target gene of miR-1296-5p, and the inhibitory effect of miR-1296-5p on HCC cell progression was rescued by TXNDC5 overexpression. Moreover, circ_0000517 promoted TXNDC5 expression via targeting miR-1296-5p.

Conclusion

Circ_0000517 accelerated HCC progression by upregulating TXNDC5 through sponging miR-1296-5p.

Metronomic therapy in pediatric oncology: A snapshot

Metronomic chemotherapy transitioned from the bench to bedside in the early 2000s and since then has carved a niche for itself in pediatric oncology. It has been used solely or in combination with other modalities such as radiotherapy, maximum tolerated dose chemotherapy, and targeted agents in adjuvant, palliative, as well as maintenance settings. No wonder, the resulting medical literature is extremely heterogeneous. In this review, the authors review and synthesize the published literature in pediatric metronomics giving a glimpse of its history, varied applications, and evolution of this genre of chemotherapy in pediatric cancers. Limitations, future prospects, and grey areas are also highlighted.

The redox regulator sulfiredoxin forms a complex with thioredoxin domain-containing 5 protein in response to ER stress in lung cancer cells

Sulfiredoxin (Srx) reduces hyperoxidized 2-cysteine-containing peroxiredoxins (Prxs) and protects cells against oxidative stress. Previous studies have shown that Srx is highly expressed in primary specimens of lung cancer patients and plays a pivotal role in lung tumorigenesis and cancer progression. However, the oncogenic mechanisms of Srx in cancer are incompletely understood. In this study, we found that Srx knockdown sensitizes lung cancer cells to endoplasmic reticulum (ER) stress-induced cell death. Through MS analysis, we determined that Srx forms a complex with the ER-resident protein thioredoxin domain-containing protein 5 (TXNDC5). Using reciprocal co-immunoprecipitation, immunofluorescence imaging, subcellular fractionation, and domain-mapping assays with site-specific mutagenesis and purified recombinant proteins, we further characterized the Srx-TXNDC5 interaction. In response to ER stress but not to oxidative stress, Srx exhibits an increased association with TXNDC5, facilitating the retention of Srx in the ER. Of note, TXNDC5 knockdown in lung cancer cells inhibited cell proliferation and repressed anchorage-independent colony formation and migration, but increased cell invasion and activation of mitogen-activated protein kinases. Using immunohistochemical staining, we demonstrate that TXNDC5 is highly expressed in patient-derived lung cancer specimens. Bioinformatics analysis of publicly available data sets revealed that those with high Srx levels have significantly shorter survival and that those with high TXNDC5 levels have longer survival. We conclude that the cellular levels of Srx and TXNDC5 may be useful as biomarkers to predict the survival of individuals with lung cancer.

TXNDC9 promotes hepatocellular carcinoma progression by positive regulation of MYC-mediated transcriptional network

The thioredoxin domain containing proteins are a group of proteins involved in redox regulation and have been recently reported to be associated with tumor progression. However, the role of thioredoxin proteins in hepatocellular carcinoma (HCC) remains largely unknown. Here in our study, we demonstrated that thioredoxin domain containing protein 9 (TXNDC9) was over-expressed in HCC and promoted HCC progression. We found that TXNDC9 expression was amplified in HCC tissues and associated with an advanced grade of HCC. And, we demonstrated that overexpression of TXNDC9 was correlated with poor prognosis of HCC. Furthermore, by using CRISPR-Cas9 mediated TXNDC9 knockout and RNA-seq analysis, we found that TXNDC9 accelerated HCC proliferation regulation. Moreover, we demonstrated that TXNDC9 directly interacted with MYC and knockout/knockdown of TXNDC9 decreased the protein levels of MYC and inhibited MYC-mediated transcriptional activation of its targets. Besides, we identified that TXNDC9 was trans-activated by FOXA1, JUND, and FOSL2 in HCC. Taken together, our study unveiled an oncogenic role of TXNDC9 in HCC and provided a mechanistic insight into the TXNDC9 mediated gene regulation network during HCC development.

A critical role of the thioredoxin domain containing protein 5 (TXNDC5) in redox homeostasis and cancer development

Correct folding of nascent peptides occurs in the endoplasmic reticulum (ER). It is a complicate process primarily accomplished by the coordination of multiple redox proteins including members of the protein disulfide isomerase (PDI) family. As a critical member of the PDI family, thioredoxin domain containing protein 5 (TXNDC5) assists the folding of newly synthesized peptides to their mature form through series of disulfide bond exchange reactions. Interestingly, TXNDC5 is frequently found overexpressed in specimens of many human diseases including various types of cancer. In this review, we summarized the biochemical function of TXNDC5 in mammalian cells and the recent progress on the understanding of its role and molecular mechanisms in cancer development. Findings of TXNDC5 in the activation of intracellular signaling pathways, stimulation of cell growth & proliferation, facilitation of cell survival and modulation of extracellular matrix to affect cancer cell invasion and metastasis are reviewed. These published studies suggest that strategies of targeting TXNDC5 can be developed as potentially valuable methods for the treatment of certain types of cancer in patients.

Role of TXNDC5 in tumorigenesis of colorectal cancer cells: In vivo and in vitro evidence

Thioredoxin domain‑containing 5 (TXNDC5) is reportedly overexpressed in colorectal cancer (CRC) and is therefore considered an oncogene. However, the role of TXNDC5 in CRC tumorigenesis remains unclear. The present study aimed to explore the role of TXNDC5 in CRC tumorigenesis in vitro and in vivo under hypoxic and normoxic conditions. Analyses of patient tissue samples revealed a positive association between the expression of hypoxia‑inducible factor‑1α (HIF‑1α) or TXNDC5 and the TNM stage of CRC. In addition, a positive correlation between the expression levels of HIF‑1α and TXNDC5 was observed in CRC tissues. Furthermore, culturing RKO and HCT‑116 human CRC cell lines under hypoxic conditions significantly increased the expression levels of HIF‑1α and TXNDC5, whereas knockdown of HIF‑1α abolished the hypoxia‑induced expression of TXNDC5. Knockdown of TXNDC5 significantly decreased cell proliferation and colony formation, and incre-ased apoptosis of both cell lines. Furthermore, knockdown of TXNDC5 markedly increased hypoxia‑induced reactive oxygen species (ROS) generation, and the expression of hypoxia‑induced endoplasmic reticulum stress (ER) markers (CCAAT‑enhancer‑binding protein homologous protein, glucose‑regulated protein 78 and activating transcription factor 4) and apoptotic markers (B‑cell lymphoma 2‑associated X protein and cleaved caspase‑8). In addition, the expression levels of TXNDC5 were significantly increased in tumor tissues compared with in adenoma and normal tissues in a mouse model of CRC tumorigenesis. In conclusion, the in vivo data demonstrated that TXNDC5 is overexpressed in CRC tissues, and this overexpression may be associated with unfavorable clinicopathological features. The in vitro data indicated that hypoxia may induce TXNDC5 expression via upregulating HIF‑1α; this effect promoted CRC cell proliferation and survival under hypoxic conditions, likely via inhibiting hypoxia‑induced ROS/ER stress signaling. These findings suggested that TXNDC5 functions as an important stress survival factor to maintain tumorigenesis of CRC cells under hypoxia by regulating hypoxia‑induced ROS/ER stress signaling. The present study provided novel insights into the role of TXNDC5 in the tumorigenesis of CRC.

Proteomic analysis of chicken embryo fibroblast cells infected with recombinant H5N1 avian influenza viruses with and without NS1 eIF4GI binding domain

Non-structural 1 (NS1) protein is a key virulence factor that regulates replication of influenza virus. A recombinant H5N1 virus lacking the eIF4GI-binding domain of NS1 (rNS1-SD30) exhibits significantly lower pathogenicity than H5N1 virus with an intact eIF4GI-binding domain (rNS1-wt). To further investigate this phenomenon, we performed comparative proteomics analyses to profile host proteins in chicken embryo fibroblasts (CEFs) infected with rNS1-wt and rNS1-SD30 viruses. In total, 81 differentially expressed (DE) proteins were identified at 12, 24, and 36 h post-infection. These proteins are mainly involved in the cytoskeletal, apoptotic and stress responses, transcription regulation, transport and metabolic processes, mRNA processing and splicing, and cellular signal transduction. Overexpression of DE proteins revealed that ANXA7 suppresses propagation of rNS1-SD30, but not rNS1-wt viruses. Moreover, ALDH7A1, ANXA7, and DCTN2 strongly enhanced IFN-β promoter activity induced by chicken MDA5 (chMDA5), and in the case of ANXA7, also by the rNS1-SD30 viral strain. NS1-wt co-transfection suppressed the ANXA7-mediated increase in IFN-β promoter activity induced by chMDA5. These findings highlight the role of NS1 eIF4GI binding domain in H5N1 pathogenicity, and may contribute to the design of antiviral strategies to reduce the high morbidity and mortality associated with this pathogen.

ERp29 inhibits tumorigenicity by suppressing epithelial mesenchymal transition in gastric cancer

ERp29 is a novel endoplasmic reticulum (ER) protein that plays an important role in protein unfolding and secretion. Recently, it has been reported to be widely implicated in control of tumorigenesis in some tumors. However, the potential function of ERp29 in gastric cancer remains poorly understood. In this study, we found that the positive rate of ERp29 in gastric cancer tissues was significantly lower than that in adjacent non-tumor tissues. And tumor with high ERp29 expression had inclinations towards smaller tumor size and earlier TNM stage. The in vitro experiments indicated that over-expression of ERp29 in gastric cancer cells significantly suppressed the proliferation and migration of tumor cells, which is consistent with the result of the in vivo animal experiments. Furthermore, our mechanistic investigations revealed that ERp29 reversed EMT process in gastric carcinoma, and its effect was related to the inactivation of ERK1/2 and AKT phosphorylation. Thus, we conclude that ERp29 acts as a tumor suppressor gene in gastric cancer, and is expected to become a novel target of the treatment of GC.

TXNDC5 is a cervical tumor susceptibility gene that stimulates cell migration, vasculogenic mimicry and angiogenesis by down-regulating SERPINF1 and TRAF1 expression

TXNDC5 (thioredoxin domain-containing protein 5) catalyzes disulfide bond formation, isomerization and reduction. Studies have reported that TXNDC5 expression is increased in some tumor tissues and that its increased expression can predict a poor prognosis. However, the tumorigenic mechanism has not been well characterized. In this study, we detected a significant association between the rs408014 and rs7771314 SNPs at the TXNDC5 locus and cervical carcinoma using the Taqman genotyping method. We also detected a significantly increased expression of TXNDC5 in cervical tumor tissues using immunohistochemistry and Western blot analysis. Additionally, inhibition of TXNDC5 expression using siRNA prevented tube-like structure formation, an experimental indicator of vasculogenic mimicry and metastasis, in HeLa cervical tumor cells. Inhibiting TXNDC5 expression simultaneously led to the increased expression of SERPINF1 (serpin peptidase inhibitor, clade F) and TRAF1 (TNF receptor-associated factor 1), which have been reported to inhibit angiogenesis and metastasis as well as induce apoptosis. This finding was confirmed in Caski and C-33A cervical tumor cell lines. The ability to form tube-like structures was rescued in HeLa cells simultaneously treated with anti-TXNDC5, SERPINF1 and TRAF1 siRNAs. Furthermore, the inhibition of TXNDC5 expression significantly attenuated endothelial tube formation, a marker of angiogenesis, in human umbilical vein endothelial cells. The present study suggests that TXNDC5 is a susceptibility gene in cervical cancer, and high expression of this gene contributes to abnormal angiogenesis, vasculogenic mimicry and metastasis by down-regulating SERPINF1 and TRAF1 expression.

Nobiletin Induces Protective Autophagy Accompanied by ER-Stress Mediated Apoptosis in Human Gastric Cancer SNU-16 Cells

Nobiletin, a major component of citrus fruits, is a polymethoxyflavone derivative that exhibits anticancer activity against several forms of cancer, including SNU-16 human gastric cancer cells. To explore the nobiletin-induced cell death mechanism, we examined the changes in protein expression caused by nobiletin in human gastric cancer SNU-16 cells by means of two-dimensional gel electrophoresis (2-DGE), followed by peptide mass fingerprinting (PMF) analysis. Seventeen of 20 selected protein spots were successfully identified, including nine upregulated and eight downregulated proteins. In nobiletin-treated SNU-16 cells the glucose-regulated protein 78 kDa (GRP78) mRNA level was induced most significantly among six proteins related to cell survival and death. Western blot analysis was used to confirm the expression of GRP78 protein. We detected increases in the levels of the ER-stress related proteins inositol requiring enzyme 1 alpha (IRE1-α), activating transcription factor 4 (ATF-4), and C/EBP homology protein (CHOP), as well as GRP78, in response to nobiletin in SNU-16 cells. Furthermore, the ER stress-mediated apoptotic protein caspase-4 was proteolytically activated by nobiletin. Pretreatment with chloroquine, an autophagy inhibitor, strongly augmented apoptosis in SNU-16 cells, as evidenced by decreased cell viability, an increased number of sub-G1 phase cells and increased levels of cleaved PARP. Our results suggest that nobiletin-induced apoptosis in SNU-16 cells is mediated by pathways involving intracellular ER stress-mediated protective autophagy. Thus, the combination of nobiletin and an autophagy inhibitor could be a promising treatment for gastric cancer patients.

ERp19 contributes to tumorigenicity in human gastric cancer by promoting cell growth, migration and invasion

ERp19, a mammalian thioredoxin-like protein, plays a key role in defense against endoplasmic reticulum stress. It belongs to the protein disulfide isomerize (PDI) family, whose members have been implicated in development of breast, ovarian and gastrointestinal cancers. However, the role of ERp19 in gastric cancer (GC) remains undefined. Therefore, we sought to investigate the expression and prognostic value of ERp19 in GC patients, and to explore the role of ERp19 in tumorigenicity. Expression of ERp19 in gastric tissues was assessed by immunohistochemical staining and real-time PCR in clinical samples of GC patients. Statistical analysis of clinical cases revealed that the expression levels of ERp19 were higher in tumor tissues than non-tumor tissues. And the level of ERp19 expression was correlated with tumor size, lymph node involvement and poor clinical prognosis. Furthermore, ERp19 knockdown dramatically suppressed gastric cancer cell growth, inhibited cellular migration/invasion and down-regulated the phosphorylation of FAK and paxillin, whereas ERp19 over-expression reversed these changes. We conclude that ERp19 contributes to tumorigenicity and metastasis of GC by activating the FAK signaling pathway, and may function as an oncogene in GC. ERp19 may represent a new diagnostic and prognostic marker and a novel target for the treatment of GC.

High TXNDC5 expression predicts poor prognosis in renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common primary kidney cancer in adults, and the identification of biomarkers involved in the pathogenesis and prognosis of ccRCC is crucial for early diagnosis and anticancer treatment. In this study, we demonstrate that thioredoxin domain-containing protein 5 (TXNDC5) expression is markedly upregulated in ccRCC tissues in comparison with adjacent non-cancerous tissues through quantitative RT-PCR, Western blotting, and immunohistochemical analyses. Importantly, TXNDC5 expression is negatively correlated with the overall survival of patients. Knockdown of TXNDC5 by siRNAs inhibits the cell growth, migration, and invasion of ccRCC cells as well as sensitizes ccRCC cells to chemotherapeutic drugs, such as Camptothecin and 5-Fluorouracil. Moreover, we used complementary DNA (cDNA) microarray analyses to explore the underlying molecular mechanisms of TXNDC5 in the pathogenesis of ccRCC. We demonstrate that knockdown of TXNDC5 affects the messenger RNA (mRNA) and protein levels of numerous important genes associated with tumorigenesis. In summary, our findings indicate that TXNDC5 performs an essential function in ccRCC pathogenesis and can serve as a novel prognostic marker of ccRCC.

An immunohistochemical study of thioredoxin domain-containing 5 expression in gastric adenocarcinoma

Thioredoxin domain-containing 5 (TXNDC5) is overexpressed in a number of human carcinomas. However, the involvement of TXNDC5 in gastric adenocarcinoma remains unclear. In the present study, the immunohistochemical expression and clinicopathological significance of TXNDC5 in gastric adenocarcinoma was investigated. The immunohistochemical expression of TXNDC5 was detected in 54 gastric adenocarcinoma specimens, and the correlation between TXNDC5 and the clinicopathological features was investigated. Of the 54 gastric adenocarcinoma specimens, 30 samples (55.6%) exhibited high TXNDC5 expression. In the adenocarcinoma specimens exhibiting high TXNDC5 expression, the proportion of poorly-differentiated adenocarcinomas was significantly higher than that in specimens exhibiting low TXNDC5 expression (P<0.05). Lymph node metastasis and the depth of tumor invasion in the specimens exhibiting high TXNDC5 expression were significantly higher than that in specimens exhibiting low TXNDC5 expression (P<0.05). The results of a survival analysis revealed that the prognosis of patients exhibiting high TXNDC5 expression was significantly poorer than that of patients exhibiting low TXNDC5 expression (P<0.05). Therefore, the expression of TXNDC5 may correlate with the differentiation, invasion and metastasis of gastric adenocarcinoma. Thus, TXNDC5 may be a tumor-enhancing gene that is involved in gastric cancer.

TXNDC5, a newly discovered disulfide isomerase with a key role in cell physiology and pathology

Thioredoxin domain-containing 5 (TXNDC5) is a member of the protein disulfide isomerase family, acting as a chaperone of endoplasmic reticulum under not fully characterized conditions As a result, TXNDC5 interacts with many cell proteins, contributing to their proper folding and correct formation of disulfide bonds through its thioredoxin domains. Moreover, it can also work as an electron transfer reaction, recovering the functional isoform of other protein disulfide isomerases, replacing reduced glutathione in its role. Finally, it also acts as a cellular adapter, interacting with the N-terminal domain of adiponectin receptor. As can be inferred from all these functions, TXNDC5 plays an important role in cell physiology; therefore, dysregulation of its expression is associated with oxidative stress, cell ageing and a large range of pathologies such as arthritis, cancer, diabetes, neurodegenerative diseases, vitiligo and virus infections. Its implication in all these important diseases has made TXNDC5 a susceptible biomarker or even a potential pharmacological target.

Metronomics: towards personalized chemotherapy?

Since its inception in 2000, metronomic chemotherapy has undergone major advances as an antiangiogenic therapy. The discovery of the pro-immune properties of chemotherapy and its direct effects on cancer cells has established the intrinsic multitargeted nature of this therapeutic approach. The past 10 years have seen a marked rise in clinical trials of metronomic chemotherapy, and it is increasingly combined in the clinic with conventional treatments, such as maximum-tolerated dose chemotherapy and radiotherapy, as well as with novel therapeutic strategies, such as drug repositioning, targeted agents and immunotherapy. We review the latest advances in understanding the complex mechanisms of action of metronomic chemotherapy, and the recently identified factors associated with disease resistance. We comprehensively discuss the latest clinical data obtained from studies performed in both adult and paediatric populations, and highlight ongoing clinical trials. In this Review, we foresee the future developments of metronomic chemotherapy and specifically its potential role in the era of personalized medicine.

The orphan nuclear receptor NR4A1 (Nur77) regulates oxidative and endoplasmic reticulum stress in pancreatic cancer cells

NR4A1 (Nur77, TR3) is an orphan nuclear receptor that is overexpressed in pancreatic cancer and exhibits pro-oncogenic activity. RNA interference of NR4A1 expression in Panc-1 cells induced apoptosis and subsequent proteomic analysis revealed the induction of several markers of endoplasmic reticulum stress, including glucose-related protein 78 (GRP78), CCAAT/enhancer-binding protein-homologous protein (CHOP), and activating transcription factor-4 (ATF-4). Treatment of pancreatic cancer cells with the NR4A1 antagonist 1,1-bis(3'-indolyl)-1-(p-hydroxyphenyl)methane (DIM-C-pPhOH) gave similar results. Moreover, both NR4A1 knockdown and DIM-C-pPhOH induced reactive oxygen species (ROS), and induction of ROS and endoplasmic reticulum stress by these agents was attenuated after cotreatment with antioxidants. Manipulation of NR4A1 expression coupled with gene expression profiling identified a number of ROS metabolism transcripts regulated by NR4A1. Knockdown of one of these transcripts, thioredoxin domain containing 5 (TXNDC5), recapitulated the elevated ROS and endoplasmic reticulum stress; thus, demonstrating that NR4A1 regulates levels of endoplasmic reticulum stress and ROS in pancreatic cancer cells to facilitate cell proliferation and survival. Finally, inactivation of NR4A1 by knockdown or DIM-C-pPhOH decreased TXNDC5, resulting in activation of the ROS/endoplasmic reticulum stress and proapoptotic pathways.

IMPLICATIONS

The NR4A1 receptor is pro-oncogenic, regulates the ROS/endoplasmic reticulum stress pathways, and inactivation of the receptor represents a novel pathway for inducing cell death in pancreatic cancer.

Endoplasmic reticulum protein ERp46 in renal cell carcinoma

An established inverse clinical correlation between serum adiponectin levels and renal cell carcinoma (RCC) aggressiveness exists. We have recently demonstrated that adiponectin suppresses clear cell RCC (ccRCC) progression through interaction with its receptor, adiponectin receptor 1 (AdipoR1). ERp46 has been shown to inhibit adiponectin signaling via interaction with AdipoR1 in HeLa cells. However, the expression of ERp46 in RCC has not been described thus far. The objectives of this study were to investigate ERp46 in RCC, its expression, its effects on RCC growth in a mouse model and whether it interacts with AdipoR1. We demonstrated a higher ERp46/AdipoR1 expression ratio in metastatic compared to non-metastatic ccRCC, as determined by immunohistochemistry of tissue microarrays and subsequent image analysis. When ERp46 was stably knocked down using shRNA or overexpressed in murine RCC RAG cells, RCC growth after subcutaneous injection in BALB/c nude mice was inhibited and accelerated, respectively. In vitro analysis to determine the molecular interaction between AdipoR1 and ERp46 included co-immunoprecipitation using human ccRCC 786-O cells and a bacterial adenylate cyclase-based two hybrid system and demonstrated no sustained AdipoR1-ERp46 interaction. This is the first report to suggest a role for ERp46 as a potential therapeutic target in RCC given its expression profile in human RCC samples and its effect on in vivo RCC growth. Since a stable interaction with AdipoR1 could not be established, we suggest that the tumorigenic properties of ERp46 in RCC cells are not related to an inhibitory modulation of AdipoR1.

Investigating a pathogenic role for TXNDC5 in tumors

The expression of TXNDC5, which is induced by hypoxia, stimulates cell proliferation and angiogenesis. The increased cell proliferation, angiogenesis and hypoxia are main features of tumor tissues. The present study aimed to characterize the expression of TXNDC5 in various tumor types and to investigate the role of TXNDC5 in the growth, proliferation and migration of tumor cells. The study also determined susceptibility of TXNDC5 gene on tumor risk. The expression of TXNDC5 in tumor tissues was determined by immunohistochemistry using a tissue array that contained various types of tumor tissues. The expression levels of TXNDC5 in tumor tissues and healthy tissues were quantitatively analyzed using western blotting. Furthermore, HeLa cells and U2OS cells were treated with anti-TXNDC5 siRNA to knockdown the expression levels of TXNDC5 to study its role in cell proliferation and migration. The cell proliferation and migration of the transfected tumor cells were determined by MTT and Transwell migration assays, respectively. Ninety-six tag SNPs across the TXNDC5 locus were genotyped using custom‑designed Illumina 384-SNP VeraCode microarrays. Our immunohistochemical staining revealed significant expression of TXNDC5 in breast invasive ductal carcinomas, cervical squamous cell carcinomas, esophageal squamous cell carcinomas, gastric carcinomas, hepatocellular carcinomas, ovarian papillary serous carcinomas, prostate cancers and undifferentiated cell carcinomas of the lung. Western blot analysis also detected significantly higher TXNDC5 expression in tumor tissues of breast cancers, gastric adenocarcinomas and rectal cancers compared to the adjacent healthy tissues. Decreased growth and invasive potential were observed in cultured HeLa cells and U2OS cells when TXNDC5 gene expression was knocked down. The case-control analysis showed a significant difference in allele frequency and genotype frequency for rs9505298, rs7771314, rs2815128, rs13210097 and rs9392182 between cervical carcinoma, esophageal carcinoma and liver cancer patients and controls. These results suggest that TXNDC5 has increased expression in many tumors that is involved in the proliferation and migration of tumor cells, acting as a tumor-enhancing gene. The study also suggests that TXNDC5 gene is susceptible to cervical carcinoma, esophageal carcinoma and liver cancer risk.

TXNDC9 expression in colorectal cancer cells and its influence on colorectal cancer prognosis

In this study, we analyzed the protein expression of thioredoxin domain containing 9 (TXNDC9) in 116 colorectal cancer (CRC) cases. Among them, 97 were positive in CRC tissues and 60 were positive in normal mucosa. TXNDC9 expression in CRC was correlated with the extent of tumor invasion and the tumor size. TXNDC9-negative patients had longer lifespans. In vitro assays showed the significant suppression of CRC cell proliferation (P < .01) compared with two control groups; the number of invaded cells also decreased (P < .01). These findings suggest that TXNDC9 gene may function in cancer development and may be an effective target for inhibiting the growth and metastasis of CRC cells.

Investigate pathogenic mechanism of TXNDC5 in rheumatoid arthritis

Hypoxia stimulates synovial hypoperfusion in rheumatoid arthritis (RA). TXNDC5 stimulates cellular proliferation in hypoxic conditions. We previously detected increased TXNDC5 expression in synovial tissues and blood from RA patients and demonstrated that the gene encoding TXNDC5 increased RA risk. The present study investigated the pathogenic roles of TXNDC5 in RA. Transgenic mice that over-expressed TXNDC5 (TXNDC5-Tg) were generated using C57BL/6J mice and treated with bovine collagen II to induce arthritis (CIA). Synovial fibroblasts from RA patients (RASFs) were cultured and incubated with TXNDC5-siRNA or CoCl(2), a chemical that induces hypoxia. CIA was observed in 80% of the TXNDC5-Tg, but only 20% of the wild-type mice (WT) developed CIA. The clinical arthritis scores reached 5 in the TXNDC5-Tg, but this index only reached 2 in the control mice. CIA TXNDC5-Tg exhibited clear pannus proliferation and bone erosion in joint tissues. A significant increase in CD4 T cells was observed in the thymus and spleen of TXNDC5-Tg during CIA. Serum levels of anti-collagen II IgG, IgG1 and IgG2a antibodies were significantly elevated in the mice. Increased cell proliferation, cell migration and TXNDC5 expression were observed in RASFs following incubation with 1 µM CoCl(2). However, this effect was diminished when TXNDC5 expression was inhibited with 100 nM siRNA. TNF-alpha, IL-1α, IL-1β and IL-17 levels were significantly increased in the blood of TXNDC5-Tg mice, but the levels of these cytokines declined in the supernatant of RASFs that were treated with TXNDC5 siRNA. The expression of adiponectin, a cytokine-like mediator, decreased significantly in RASFs following TXNDC5 siRNA treatment. These results suggest that TXNDC5-over-expressing mice were susceptible to CIA. This study also suggests that hypoxia induced TXCNDC5 expression, which contributed to adiponectin expression, cytokine production and the cellular proliferation and migration of fibroblasts in RA.