Paired Gastric Cancer Tissues Research Articles

Circular RNA CircSLC22A23 Promotes Gastric Cancer Progression by Activating HNRNPU Expression.

Circular RNAs (CircRNAs) play essential roles in cancer occurrence as regulatory RNAs. However, circRNA-mediated regulation of gastric cancer (GC) remains poorly understood. Thepurposeofthisstudywastoinvestigatethe molecular mechanism of circSLC22A23 (hsa_circ_0075504) underlying GC occurrence. CircSLC22A23 levels were first quantified by quantitative real-time reverse transcription-polymerase chain reaction in GC cell lines, 80 paired GC tissues and adjacent normal tissues, and 27 pairs of plasma samples from preoperative and postoperative patients with GC. Then circSLC22A23 was knocked-down with short hairpin RNA to analyze its oncogenic effects on the proliferation, migration, and invasion of GC cells. Finally, circRNA-binding proteins and their downstream target genes were identified by RNA pulldown, mass spectrometry, RNA immunoprecipitation, quantitative real-time reverse transcription-polymerase chain reaction, and Western blot assays. CircSLC22A23 was found to be highly expressed in GC cells, GC tissues, and plasma from GC patients. Knockdown of circSLC22A23 inhibited GC cell proliferation, migration and invasion. RNA pulldown and RNA immunoprecipitation assays verified the interaction between circSLC22A23 and heterogeneous nuclear ribonucleoprotein U (HNRNPU). Knockdown of circSLC22A23 decreased HNRNPU protein levels. Moreover, rescue assays showed that the tumor suppressive effect of circSLC22A23 knockdown was reversed by HNRNPU overexpression. Finally, epidermal growth factor receptor (EGFR) was found to be one of the downstream target genes of HNRNPU that was up regulated by circSLC22A23. CircSLC22A23 regulated the transcription of EGFR through activation of HNRNPU in GC cells, suggesting that circSLC22A23 may serve as a potential therapeutic target for the treatment of GC.

Targeting Ubiquitin-specific Protease 5 Overcomes Chemoresistance via Negatively Regulating p53 in Gastric Cancer.

Resistance to chemotherapy is a major obstacle in the clinical management of gastric cancer, and the mechanisms underlying chemoresistance remain largely unknown. This study aimed to investigate the involvement of ubiquitin-specific protease 5 (USP5), a deubiquitinating enzyme, in gastric cancer chemoresistance Methods: USP5 expression was analyzed in fifty paired gastric cancer and adjacent normal tissues, chemo-sensitive and chemo-resistant gastric cancer lines using quantitative ELISA. The role of USP5 was determined using loss-of-function and gainof- function methods. USP5-mediated downstream effectors were analyzed using biochemical methods focusing on p53. USP5 expression was comparable in tumors and normal in the majority of the cohort. Following chemotherapy treatment, USP5 expression significantly increased in gastric cancer cells, while p53 levels remained unaltered. Overexpression of USP5 amplified growth and migration while decreasing apoptosis induced by serum withdrawal across multiple gastric cancer cell lines. Conversely, USP5 knockdown effectively heightened gastric cancer sensitivity to paclitaxel and 5-FU treatments, particularly targeting chemo-resistant gastric cancer cells by inhibiting proliferation and migration and inducing apoptosis. Additionally, USP5 knockdown increased levels of p53 but not MDM2, increased p53 activity and increased transcription of p53 target genes. In contrast, USP5 overexpression decreased the level and activity of p53 and inhibited transcription of p53 target genes. The anti-proliferative, anti-migratory, and pro-apoptotic effects of USP5 were significantly diminished upon p53 depletion, highlighting the interplay between p53 and USP5 in regulating gastric cancer cell activities. Additionally, USP5 inhibition suppressed chemo-resistant gastric cancer cell migration via suppressing epithelial-mesenchymal transition (EMT) and RhoA activity. Targeting USP5 inhibition has emerged as a promising alternative therapeutic approach to overcoming chemoresistance in gastric cancer. Additionally, our study sheds light on the novel role of USP5 as a regulator of p53 in gastric cancer.

Tumor-derived Prevotella intermedia aggravates gastric cancer by enhancing Perilipin 3 expression.

The indigenous microbial milieu within tumorous tissues exerts a pivotal influence on the genesis and advancement of gastric cancer (GC). This investigation scrutinizes the functions and molecular mechanisms attributed to Prevotella intermedia in the malignant evolution of GC. Isolation of P. intermedia from paired GC tissues was undertaken. Quantification of P. intermedia abundance in 102 tissues was accomplished using quantitative real-time PCR (qRT-PCR). Assessment of the biological effects of P. intermedia on GC cells was observed using culture medium supernatant. Furthermore, the protein profile of GC cells treated with tumor-derived P. intermedia was examined through label-free protein analysis. The functionality of perilipin 3 (PLIN3) was subsequently confirmed using shRNA. Our investigation revealed that the relative abundance of P. intermedia in tumor tissues significantly surpassed that of corresponding healthy tissues. The abundance of P. intermedia exhibited correlations with tumor differentiation (p = 0.006), perineural invasion (p = 0.004), omentum majus invasion (p = 0.040), and the survival duration of GC patients (p = 0.042). The supernatant derived from tumor-associated P. intermedia bolstered the proliferation, clone formation, migration, and invasion of GC cells. After indirect co-cultivation with tumor-derived P. intermedia, dysregulation of 34 proteins, including PLIN3, was discerned in GC cells. Knockdown of PLIN3 mitigated the malignancy instigated by P. intermedia in GC cells. Our findings posit that P. intermedia from the tumor microenvironment plays a substantial role in the malignant progression of GC via the modulation of PLIN3 expression. Moreover, the relative abundance of P. intermedia might serve as a potential biomarker for the diagnosis and prognosis of GC.

Circular RNA circWNK1 inhibits the progression of gastric cancer via regulating the miR-21-3p/SMAD7 axis.

Gastric cancer (GC) is a highly aggressive malignancy with limited treatment options for advanced-stage patients. Recent studies have highlighted the role of circular RNA (circRNA) as a novel regulator of cancer progression in various malignancies. However, the underlying mechanisms by which circRNA contributes to the development and progression of GC remain poorly understood. In this study, we utilized microarrays and real-time quantitative polymerase chain reaction (qRT-PCR) to identify and validate a downregulated circRNA, hsa_circ_0003251 (referred to as circWNK1), in paired GC and normal tissues. Through a series of invitro and invivo gain-of-function and loss-of-function assays, we demonstrated that circWNK1 exerts inhibitory effects on the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of GC cells. Additionally, we discovered that circWNK1 acts as a competitive endogenous RNA (ceRNA) for SMAD7 by sequestering miR-21-3p. Our findings were supported by comprehensive biological information analysis, as well as RNA pull-down, luciferase reporter gene, and western blot assays. Notably, the downregulation of circWNK1 in GC cells resulted in reduced SMAD7 expression, subsequently activating the TGF-β signaling pathway. Collectively, our study reveals that circWNK1 functions as a tumor suppressor in GC by regulating the miR-21-3p/SMAD7-mediated TGF-β signaling pathway. Furthermore, circWNK1 holds promise as a potential biomarker for the diagnosis and treatment of GC.

UBE2R2-AS1, as a prognostic marker of gastric cancer, promotes the malignant phenotype of gastric cancer cells.

This study aimed to unveil the potential of UBE2R2-AS1 dysregulation in gastric cancer. In addition, its biological function was assessed. UBE2R2-AS1 expression was predicted in the ENCORI database. Paired gastric cancer and noncancerous tissues were collected. UBE2R2-AS1 expression was confirmed using RT-qPCR in our patient set. The association of UBE2R2-AS1 with the clinical data of patients was analyzed. Evaluation of the prognostic value of UBE2R2-AS1 was via Kaplan-Meier and Univariate/Multivariate Cox analyses. The effect of UBE2R2-AS1 on the cancer cell malignant phenotype was investigated. Gastric cancer tissues and cells significantly overexpressed UBE2R2-AS1. UBE2R2-AS1 was significantly more abundant in unfavorable clinical pathology, including advanced TNM stage and lymph node metastasis. High expression of UBE2R2-AS1 predicted a poor prognosis with a hazard ratio (HR) of 3.041 and 2.805 after Univariate and Multivariate Cox analysis, respectively. UBE2R2-AS1 can act as a sponge for miR-302b-5p to promote cell proliferation, migration, and invasion of gastric cancer. The expression of UBE2R2-AS1 allowed the prognostic stratification of gastric cancer patients. UBE2R2-AS1 may accelerate the progression of gastric cancer via miR-302b-5p.

Long noncoding RNA PSMA3-AS1 functions as a competing endogenous RNA to promote gastric cancer progression by regulating the miR-329-3p/ALDOA axis

LncRNA PSMA3-AS1 functions as an oncogene in several cancers, including ovarian cancer, lung cancer, and colorectal cancer. However, its role in gastric cancer (GC) progression remains unclear. In this study, the levels of PSMA3-AS1, miR-329-3p, and aldolase A (ALDOA) in 20 paired human GC tissues and adjacent nontumorous tissues were measured by real-time PCR. GC cells were transfected with recombinant plasmid carrying full-length PSMA3-AS1 or shRNA targeting PSMA3-AS1. The stable transfectants were selected by G418. Then, the effects of PSMA3-AS1 knockdown or overexpression on GC progression in vitro and in vivo were evaluated. The results showed that PSMA3-AS1 was highly expressed in human GC tissues. Stable knockdown of PSMA3-AS1 significantly restrained proliferation/migration/invasion, enhanced cell apoptosis, and induced oxidative stress in vitro. Tumor growth and matrix metalloproteinase expression in tumor tissues were markedly inhibited, while oxidative stress was enhanced in nude mice after stable PSMA3-AS1 knockdown. Additionally, PSMA3-AS1 negatively regulated miR-329-3p while positively regulated ALDOA expression. MiR-329-3p directly targeted ALDOA-3′UTR. Interestingly, miR-329-3p knockdown or ALDOA overexpression partially attenuated the tumor-suppressive effects of PSMA3-AS1 knockdown. Conversely, PSMA3-AS1 overexpression exhibited the opposite effects. PSMA3-AS1 promoted GC progression by regulating the miR-329-3p/ALDOA axis. PSMA3-AS1 might serve as a promising and effective target for GC treatment.

MIR-147B Regulated Proliferation and Apoptosis of Gastric Cancer Cells by Targeting CPEB2 Via the PTEN Pathway.

The present study has been performed to illustrate the role and mechanism of microRNA-147b (miR-147b) in the cellular viability and apoptosis of gastric cancer (GC) cells. The GC tissues of 50 patients with complete data and the adjacent tissues were selected from Shanxi Cancer Hospital, and 3 pairs of tissues were randomly selected for microarray detection of high-expressing microRNAs. The expressions of miR-147b were quantified in numerous GC cell lines, i.e., BGC-823, SGC-7901, AGS, MGC-803 and MKN-45, normal tissue cell lines and 50 pairs of gastric cancer tissues. Moreover, two cell lines of miR-147b high-expressing used PCR quantitative analysis were selected for transfection experiments. The differentially expressed miR-147b was screened from 3 pairs of samples by miRNA chip. The expression ofmiR-147b was found highly expressed in gastric cancer tissues of 50 pairs of gastric cancer and adjacent tissues. The miR-147b found in diverse range in each of GC cell line. Therefore, two cell lines, BGC-823 and MGC-803, with relatively high expression levels of miR-147b were selected for further analysis and research. Scratch analysis results showed that compared with miR-147b NC, the miR-147b inhibitor group inhibited GC cell growth and reduced cell migration. The early apoptosis of MGC-803, and BGC-823 cells was enhanced by miR-147b inhibitor. miR-147b inhibitor significantly repressed the proliferation of BGC-823 and MGC-803 cells. Our study showed that the high expression of miR-147b is positively correlated with the occurrence and development of gastric cancer.

Serum tRF-27-FDXXE6XRK45 as a Promising Biomarker for the Clinical Diagnosis in Gastric Cancer.

Objective: Gastric cancer (GC) has high morbidity and mortality due to inefficient early screening. Therefore, we are searching for more sensitive and specific diagnostic markers for GC. tRNA-derived small RNAs are novel non-coding small RNAs with good abundance and stable presence in body fluids, which may play multiple biological regulatory roles. In this study, we aimed to find a potential biomarker with high accuracy in tRNA-derived small RNAs that can help diagnose GC. Methods: tRF-27-FDXXE6XRK45 was screened as a target molecule by high-throughput sequencing in three pairs of GC tissues. RNA quantitative reverse transcription PCR was conducted to detect the expression levels of tRF-27-FDXXE6XRK45. Agarose gel electrophoresis, Sanger sequencing, cytoplasmic and nuclear RNA isolation assays, gradient dilution experiments, and room temperature and repeated freeze-thaw experiments were used to assess the detection performance of tRF-27-FDXXE6XRK45. Using the chi-square test to analyze the correlation between tRF-27-FDXXE6XRK45 expression levels and clinicopathological parameters. In addition, receiver operating characteristic curves were used to evaluate the diagnostic value of tRF-27-FDXXE6XRK45 in GC. Results: tRF-27-FDXXE6XRK45 expression levels, significantly upregulated in tissues and sera of GC patients and decreased after radical GC surgery, were correlated with the degree of differentiation, depth of tumor infiltration, TNM stage, lymph node metastasis, and nerve/vascular invasion. In comparison with current GC diagnostic markers, tRF-27-FDXXE6XRK45 displayed better efficacy. Conclusions: tRF-27-FDXXE6XRK45, with high diagnostic efficacy, can distinguish GC patients from gastritis patients and healthy donors, suggesting that tRF-27-FDXXE6XRK45 may be a promising candidate as a diagnostic marker for GC.

Identification of Potential Diagnostic and Prognostic Biomarkers for Gastric Cancer Based on Bioinformatic Analysis.

Gastric cancer (GC) ranks third for cancer-related fatalities worldwide. It is still unclear what causes GC to progress. Using integrated bioinformatics analysis, COL5A2 has been proved to be related to GC development, which may identify the likely pathogenic mechanism. Data from GC patients were gathered using The Cancer Gene Atlas (TCGA) and the gene expression omnibus (GEO). The level of COL5A2 expression was compared between paired GC and normal tissues. The differentially expressed genes (DEGs) in GC patients with high and low COL5A2 expression were identified using functional enrichment analysis to identify the signature pathways linked to the DEGs. The clinical pathologic traits connected to overall survival (OS) of GC patients were examined utilizing Cox regression and the Kaplan-Meier method. To assess the prognostic significance of COL5A2, receiver operating characteristic (ROC) curves was drawn. How the immune system infiltrate both normal gastric and GC tumor tissues was investigated. Using the human protein atlas (HPA) database, regression, and the Kaplan-Meier method, immunohistochemical analysis of DEG COL5A2 expression in GC tissues was carried out. The correlation between COL5A2 expression and the GC grouping was found to be highly significant. Functional annotations revealed that COL5A2 participates in extracellular matrix structure, collagen metabolism, and other biological processes (BPs). High COL5A2 expression was associated with poor prognostic and clinical features, such as clinical T, N, and M stages. ROC curves exhibited that COL5A2 might predict the occurrence of gastric cancer. The infiltration degree of 21 immune cell subsets, including activated dendritic cells (aDCs), CD8+ T cells, and cytotoxic cells, was found to be dramatically relevant to COL5A2. Immunohistochemical analysis indicated that the expression of COL5A2 in tumor tissues is higher than that in normal tissues. The COL5A2 gene may offer fresh perspectives on the pathogenic mechanism underlying GC, as well as potential biomarkers for estimating GC patient prognosis. As a result, COL5A2 may be a useful biomarker for predicting patient survival.

MST4 as a novel therapeutic target for autophagy and radiosensitivity in gastric cancer.

Mammalian ste20-like kinase 4 (MST4) and autophagy have been implicated in ailments such as inflammatory and cancers. In this study, the expression of MST4 data was extracted from TCGA, GTEx, and GEPIA. The infiltration of immune cells and methylation level of MST4 in tumor and normal tissues were extracted from GEPIA 2021, TISIDB, UALCAN, EWAS, MethSurv, and MEXPRESS database. We also predict the efficacy of outcome prediction with receiver operating characteristic curve (ROC). All proteins expressions of MST4, P62, and LC3 were detected by immunohistochemistry (IHC) in paired Gastric cancer (GC) and para-cancerous normal tissue samples. We verify the effects of MST4 on irradiation-induced gastric death, and also investigate effects of MST4 activating autophagy in GC cell lines with various in vitro assays using western blotting. We have confirmed the high transcription level of MST4 from TCGA, USLCAN, HPA, and other portals, but a rapid decrease in protein level. More, MST4 can be considered as an independent prognostic molecule, which has significant prognostic significance in tumor grade, anti-tumor treatment, histological type, and time-dependent ROC curve. The methylation degree of MST4 promoter region in tumor is much lower than that in normal tissue, which may be the main reason for the remarkably high transcription level of MST4. In addition, MST4 transcription level was significantly inversely proportional to the infiltration level of most immune cells. The MST4 up-regulation and the positive association of MST4 with autophagy expression were cross-validated in open-access datasets. MST4, as an autophagy-associated protein, plays a potential role in inducing cell death by increasing protein content in radiotherapy.

Upregulation of lncRNA HITT promotes cell apoptosis by suppressing the maturation of miR-602 in gastric cancer.

It has been reported that HITT can inhibit colon cancer. However, the role of HITT in gastric cancer (GC) is unknown. Our preliminary sequencing data revealed the altered expression of HITT in GC and its close correlation with miR-602, suggesting the involvement of HITT and its potential interaction with miR-602 in GC. This study explored the role of HITT and its crosstalk with miR-602 in GC. In this study, the expression of HITT, premature and mature miR-602 in paired GC and normal tissues (62 patients) was detected by RT-qPCR. RNA pull-down assay was performed to evaluate the direct interaction between HITT and mature miR-602. The subcellular location of HITT was assessed by nuclear fractionation assay. The role of HITT in regulating miR-602 maturation was explored by overexpression assay. Cell apoptosis was analyzed by flow cytometry. Our data illustrated that HITT was highly upregulated and mature miR-602 was downregulated in GC. No alteration in premature miR-602 in GC was observed. HITT was located in both nucleus and cytoplasm, and it can directly interact with miR-602. In addition, overexpression of HITT in GC cells increased the expression levels of mature miR-602 but not premature miR-602. Overexpression of HITT further increased GC cell apoptosis and suppressed the role of miR-602 in inhibiting GC cell apoptosis. In conclusion, HITT may promote GC cell apoptosis by suppressing the maturation of miR-602.

MiR-378a-3p acts as a tumor suppressor in gastric cancer via directly targeting RAB31 and inhibiting the Hedgehog pathway proteins GLI1/2.

To improve the prognosis of patients with gastric cancer (GC), more effective therapeutic targets are urgently needed. Increasing evidence indicates that miRNAs are involved in the progression of various tumors, and RAS-associated protein in the brain 31 (RAB31) is upregulated and promotes the progression of multiple malignant tumors. Here, we focused on identifying RAB31-targeted miRNAs and elucidating their potential mechanism in the progression of GC. RAB31 and miR-378a-3p expression levels were detected in paired fresh GC tissues and GC cell lines. Bioinformatics analysis was used to predict the miRNAs targeting RAB31 and the relationships between RAB31 and other genes. Dual-luciferase reporter assays were applied to verify the targeted interaction relationship. CCK-8, colony formation, flow cytometry, wound healing, and Transwell assays were performed to assess the proliferation, apoptosis, migration, and invasion of GC cells. Tumorsphere formation assays were performed to assess the stemness of gastric cancer stem cells. Related proteins were detected by Western blot. Xenograft assays in nude mice were performed to explore the effect of miR-378a-3p in vivo. We report the first evidence that miR-378a-3p is downregulated in GC, whereas its overexpression inhibits proliferation, invasion, and migration as well as promotes apoptosis in GC cells. Mechanistically, miR-378a-3p inhibits the progression of GC by directly targeting RAB31. Restoring RAB31 expression partially offsets the inhibitory effect of miR-378a-3p. Further research revealed that miR-378a-3p inhibits GLI1/2 in the Hedgehog signaling pathway and attenuates the stemness of gastric cancer stem cells. Finally, xenograft assays showed that miR-378a-3p inhibits GC tumorigenesis in vivo. MiR-378a-3p inhibits GC progression by directly targeting RAB31 and inhibiting the Hedgehog signaling pathway proteins GLI1/2.

Interleukin-34 promotes the proliferation and epithelial-mesenchymal transition of gastric cancer cells.

BACKGROUNDInterleukin (IL)-34 is a pro-inflammatory cytokine involved in tumor development. The role of IL-34 in the proliferation and epithelial-mesenchymal transition (EMT) of gastric cancer (GC) remains to be investigated.AIMTo investigate whether and how IL-34 affects the proliferation of GC cells and EMT.METHODSUsing immunohistochemical staining, the expression of IL-34 protein was detected in 60 paired GC and normal paracancerous tissues and the relationship between IL-34 and clinicopathological factors was analyzed. The expression of IL-34 mRNA and protein in normal gastric epithelial cell lines and GC was detected using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting, respectively. Stable IL-34 knockdown and overexpression in AGS cell lines were established by lentiviral infection and validated by qRT-PCR and western blotting. The cholecystokinin-8 assay, clone formation assay, cell scratch assay, and transwell system were used to detect GC cell proliferation, clone formation, migration, and invasion capacity, respectively. The effects of IL-34 on the growth of GC transplant tumors were assessed using a subcutaneous transplant tumor assay in nude mice. The effects of IL-34 on the expression level of EMT-associated proteins in AGS cells were examined by western blotting.RESULTSExpression of IL-34 protein and mRNA was higher in GC cell lines than in GES-1 cells. Compared to matched normal paraneoplastic tissues, the expression of IL-34 protein was higher in 60 GC tissues, which was correlated with tumor size, T-stage, N-stage, tumor, node and metastasis stage, and degree of differentiation. Knockdown of IL-34 expression inhibited the proliferation, clone formation, migration, and invasion of AGS cells, while overexpression of IL-34 promoted cell proliferation, clone formation, migration, and invasion. Furthermore, the reduction of IL-34 promoted the expression of E-cadherin in AGS cells but inhibited the expression of vimentin and N-cadherin. Overexpression of IL-34 inhibited E-cadherin expression but promoted expression of vimentin and N-cadherin in AGS cells. Overexpression of IL-34 promoted the growth of subcutaneous transplanted tumors in nude mice.CONCLUSIONIL-34 expression is increased in GC tissues and cell lines compared to normal gastric tissues or cell lines. In GC cells, IL-34 promoted proliferation, clone formation, migration, and invasion by regulating EMT-related protein expression cells. Interference with IL-34 may represent a novel strategy for diagnosis and targeted therapy of GC.

Phosphoglycerate mutase 1 that is essential for glycolysis may act as a novel metabolic target for predicating poor prognosis for patients with gastric cancer.

To identify a novel marker for gastric cancer, we examined the usefulness of phosphoglycerate mutase 1 (PGAM1) as a potential diagnostic marker using isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics and evaluated its clinical significance. Proteins from a discovery group of four paired gastric cancer tissues and adjacent gastric tissues were labeled with iTRAQ reagents and then identified and quantified using LC-MS/MS. The expression of PGAM1 was further validated in 139 gastric cancer patients using immunohistochemistry. Furthermore, the correlation of PGAM1 expression with clinical parameters was analyzed. Gene set enrichment analysis (GSEA) was performed to identify gene sets that were activated in PGAM1-overexpressing patients with gastric cancer. PGAM1 was significantly overexpressed in most cancers but particularly so in gastric cancer, with a sensitivity of 82.01% (95% confidence interval [CI]: 75.5%-88.5%) and specificity of 79.13% (95% CI: 72.3%-86%). Its expression was significantly associated with histological grade II and III tumors (p=0.033), lymph node metastasis (p=0.031), and TNM III-IV staging (p=0.025). The area under the receiver operating characteristic (ROC) curve for the detection of PGAM1 overexpression in gastric cancer was 0.718 (p < 0.01). Furthermore, GSEA revealed that several important pathways such as glycolysis pathway and immune pathways were significantly enriched in patients with gastric cancer with PGAM1 overexpression. This study provided a sensitive method for detecting PGAM1, which may serve as a novel indicator for poor prognosis of gastric cancer, as well as a potent drug target for gastric cancer.

The role of circular RNA hsa_circ_0001789 as a diagnostic biomarker in gastric carcinoma

Background Circular RNA (circRNA) is a kind of endogenous non-coding RNAs and has shown diagnostic values in various cancers. This study aimed to explore whether hsa_circ_0001789 could be a novel biomarker for gastric cancer (GC). Methods Quantitative reverse transcriptase PCR was used to detect the expression of hsa_circ_0001789 in 108 paired GC and paracancerous tissues as well as in 24 paired plasma specimens. Possible associations between hsa_circ_0001789 expression and clinicopathologic factors of GC patients were examined using one-way ANOVA. A receiver operating characteristic (ROC) curve was established to investigate the diagnostic value of hsa_circ_0001789 in GC. Results GC tissues and plasma samples showed down-regulated hsa_circ_0001789 levels than their counterparts, which were closely correlated with the malignant characteristics of GC. The area under the ROC curve (AUC) of hsa_circ_0001789 in GC tissues was 0.82, while the cut-off value was 9.5, indicating a favorable diagnostic value. Compared with the traditional tumor biomarkers, hsa_circ_0001789 had preferred AUCs that reached 0.786 for predicting the stage of invasion, 0.603 for predicting the stage of lymphatic metastasis, 0.722 for predicting the stage of distant metastasis, and 0.786 for predicting TNM stage. Conclusions Hsa_circ_0001789 may be a novel biomarker for the diagnosis of gastric carcinoma.

Ornithine aminotransferase and carbamoyl phosphate synthetase 1 involved in ammonia metabolism serve as novel targets for early stages of gastric cancer.

ObjectiveThe sensitivity and specificity of current biomarkers for gastric cancer were insufficient. The aim of the present study was to screen novel biomarkers and determine the diagnostic values of ornithine aminotransferase (OAT) and carbamoyl phosphate synthetase 1 (CPS1) for detecting gastric cancer.MethodsWith stable isotope tags, we labelled an initial discovery group of four paired gastric cancer tissue samples and identified with LC‐ESI‐MS/MS. A validation group of 159 gastric cancer samples and 30 healthy controls were used to validate the candidate targets. GSEA was used to explore the pathways activated in gastric cancer.ResultsFour hundred and thirty one proteins were found differentially expressed in gastric cancer tissues. Of these proteins, OAT and CPS1 were found over‐expressed in gastric cancer patients, with sensitivity of 70.4% (95% CI: 63.3%–77.6%) and specificity of 80.5% (95% CI: 74.3%–86.7%) for ornithine aminotransferase, and with sensitivity of 68.6% (95% CI: 61.3%–75.8%) and specificity of 73% (95% CI: 66%–79.9%) for carbamoyl phosphate synthetase 1. The co‐expression of OAT and CPS1 in gastric cancer tissues has a sensitivity of 81% (95% CI: 73.2%–88.8%) and specificity of 89% (95% CI: 83%–95%). Furthermore, both OAT and CPS1 were overexpressed in patients with local invasion T3 and T4 stages than those in patients with T1 and T2 stages. The co‐expression of OAT and CPS1 was strongly correlated with histological grade I 68% (95% CI: 58.7%–77.3%) and TNM stage I/II 52% (95% CI: 42%–62%). The areas under ROC curves were up to 0.758 for the co‐expression of OAT and CPS1 in gastric cancer. GSEA results showed that two gene sets and 30 gene sets were activated in OAT high‐ and CPS1 high‐expression patients with gastric cancer, respectively.ConclusionsThe present findings indicated a tight correlation between the co‐expression of OAT and CPS1 and the histological grade, local invasion, and TNM stages of gastric cancer. Therefore, OAT and CPS1 might be predictors for gastric cancer invasion and potential targets for anticancer drug design for gastric cancer.

Overexpression of lncRNA TCLlnc1 in gastric cancer predicts postoperative distant recurrence and poor survival.

TCLlnc1 was characterized as a lncRNA with oncogenic roles in T cell lymphoma, whereas its role in other diseases is unknown. We then explored the involvement of TCLlnc1 in gastric cancer. Paired gastric cancer and nontumor tissues from 66 gastric cancer patients were used to extract total RNA samples, which were used to perform RT-qPCRs to determine the expression of TCLlnc1. Plasma samples from these 66 gastric cancer patients and 66 healthy controls were also used to detect circulating TCLlnc1. Correlations of TCLlnc1 in both plasma and tissue samples with patients’ clinical data were analyzed by chi-square t-test. The diagnostic value of TCLlnc1 for early-stage gastric cancer was analyzed with the receiver operating characteristic curve. A 5-year follow-up study was performed to explore the prognostic value of TCLlnc1 for the survival of gastric cancer patients. TCLlnc1 expression in tissue was increased in gastric cancer. Plasma TCLlnc1 was also increased in gastric cancer. Plasma TCLlnc1 was closely correlated with TCLlnc1 in gastric cancer tissues, but not TCLlnc1 in nontumor tissues. TCLlnc1 in plasma was only correlated with tumor distant metastasis, but not other clinical data. TCLlnc1 in plasma showed promising diagnostic value for stage I and II gastric cancer. Increased accumulation of TCLlnc1 was closely correlated with distant recurrence and poor survival during a 5-year follow-up. Therefore, TCLlnc1 is overexpressed in gastric cancer predicts postoperative distant recurrence and poor survival.

MiR-548 predicts clinical prognosis and functions as a tumor promoter in gastric cancer.

Numerous pieces of evidence have demonstrated the functional role of miR-548 in various cancers. The expression and function of miR-548 in gastric cancer were investigated in the present study. A total of 123 gastric cancer patients were included and provided paired gastric cancer tissues and matched normal tissues. RT-qPCR was used to detect the expression of miR-548. CCK8 assay was used to evaluate cell proliferation, and Transwell assay was applied to assess cell migration and invasion. The clinical significance of miR-548 was estimated by a series of statistical analyses. miR-548 was found to be upregulated in gastric cancer, which was associated with the lymph node metastasis and TNM stage of patients. Patients with relatively high miR-548 expression possessed bad survival. miR-548 was identified as a prognostic indicator of gastric cancer. miR-548 was also found to promote the proliferation, migration, and invasion of gastric cancer. Upregulated miR-548 was involved in the progression of gastric cancer and predicted the prognosis of patients. Inhibition of miR-548 might be a novel therapeutic strategy for gastric cancer.

A 5`-tRNA Derived Fragment NamedtiRNA-Val-CAC-001 Works as a Suppressor in Gastric Cancer.

BackgroundGastric cancer (GC) is a common type of gastrointestinal tumor in the world. Transfer RNA (tRNA) derived fragments (tsRNAs) implicate various cancers, but their roles in GC remain unclear. Our study aimed to investigate the potential biological functions and molecular mechanisms of tsRNAs in GC.MethodsDifferentially expressed tsRNAs were identified using high-throughput sequencing. The expression levels of tsRNAs were validated in 62 paired GC tissues and adjacent normal tissues using RT-qPCR. In vitro functional assays were used to evaluate the influences of tsRNAs on GC cells. The potential mechanisms underlying tsRNAs were explored using bioinformatics analysis,RT-qPCR, RNA immunoprecipitation assays and Western blot.ResultsWe found that tiRNA-Val-CAC-001 was downregulated in GC tissues and cells, and demonstrated that tiRNA-Val-CAC-001 was a tsRNA sheared from mature tRNA-Val and mainly localized in the cytoplasm. tiRNA-Val-CAC-001 overexpression inhibited metastasis and proliferation but promoted apoptosis of GC cells; nevertheless, tiRNA-Val-CAC-001 knockdown increased metastasis and proliferation and reduced apoptosis (P<0.05). GO and KEGG analyses indicated tiRNA-Val-CAC-001 may exert its effects via Wnt/β-catenin signaling pathway by targeting LRP6. Following experiments showed that tiRNA-Val-CAC-001 could downregulated the protein levels of LRP6 and β-catenin, but up-regulated p-β-catenin, which confirmed the findings in bioinformatics analysis.ConclusionIn conclusion, tiRNA-Val-CAC-001 works as a cancer suppressor in GC by targeting LRP6 via Wnt/β-catenin signaling pathway. tiRNA-Val-CAC-001 may serve as a therapy target and a biomarker of GC in the future.Key PointstiRNA-Val-CAC-001 is downregulated in gastric cancer tissues and cell lines, tiRNA-Val-CAC-001 has potential to become a novel diagnostic biomarker in gastric cancer, and tiRNA-Val-CAC-001 regulates gastric cancer cells by targeting LRP6.

Interplay of Helicobacter pylori, fibroblasts, and cancer cells induces fibroblast activation and serpin E1 expression by cancer cells to promote gastric tumorigenesis

BackgroundHelicobacter pylori (H. pylori) can disrupt the tight junctions between gastric epithelial cells and penetrate the intercellular spaces acting on epithelial cells, normal fibroblasts (NFs), and cancer-associated fibroblasts (CAFs), but their interaction in gastric cancer tumorigenesis and progression remains unclear.MethodsPrimary CAFs and NFs were isolated from paired gastric cancer tissues and adjacent normal tissues and identified by immunofluorescence staining and western blot analysis for FSP-1, α-SMA, FAP, and vimentin expression. RNA-sequencing was used to compare the transcriptomes between CAFs and NFs. The expressions of FAP, lumican, and α-SMA, human cytokine array, and Transwell assay were used to assess the transformation of NFs to CAFs. CCK-8 assay, colony formation, flow cytometry, Transwell assay, and nude mouse xenograft model were used to determine the effects of Serpin E1 on cell proliferation and metastasis in vitro and in vivo. Finally, Serpin E1 and/or FAP expression was measured in H. pylori-infected gerbil gastric mucosa and human gastric cancer tissues.ResultsGastric CAFs are inflammatory CAFs with α-SMAlowFAPhighlumicanhigh. The interplay of H. pylori, fibroblasts, and cancer cells promotes the transition of NFs to CAFs by inducing cytokine release, especially Serpin E1. Long-term H. pylori infection and CAFs induce Serpin E1 expression in gerbil gastric tissues and human gastric cancer cells. Serpin E1 overexpression enhances the growth, migration, invasion of gastric cancer cells in vitro, and xenograft tumor growth in nude mice via inducing angiogenesis. Serpin E1 and FAP were highly expressed in cancer cells and CAFs of gastric cancer tissues, respectively, and a good correlation was observed between their expression. Higher Serpin E1 expression is negatively associated with the overall survival of patients with gastric cancer.ConclusionsThe interplay of H. pylori, fibroblasts, and cancer cells induced Serpin E1 expression to promote the activation of NFs to CAFs and gastric carcinogenesis. Targeting Serpin E1 will provide a promising therapeutic strategy for gastric cancer by disrupting the interaction between H. pylori, CAFs, and gastric cancer cells.