Poor Prognosis In Gastric Cancer Patients Research Articles

Impact of Androgen Receptor Gene Expression in Gastric Cancer: a Meta-Analysis Based on the GEO Database, TCGA Database, and Literature

To evaluate androgen receptor and AR gene expression impact of gastric cancer (GC). Meta-analysis of microarray data obtained from the Gene Expression Omnibus (GEO) database, TCGA (The Cancer Genome Atlas) database, and data by systematic search of PubMed, China National Knowledge Internet and Web of Science. This meta-analysis included 30 studies involving 4487 patients. From our results, we can know that the positive rate of AR expression in gastric cancer is 40%. The expression of AR was significantly higher in men (SWD = 1.00, 95% CI 0.03 ~ 1.96, P = 0.042). The higher AR expression was linked with poor over survival (OS) (HR = 1.30, 95% CI 1.13 ~ 1.49, P < 0.0001). AR gene may be an important factor affecting the poor prognosis of GC patients of different genders.

Circular RNA MCTP2 inhibits cisplatin resistance in gastric cancer by miR-99a-5p-mediated induction of MTMR3 expression

BackgroundCisplatin (CDDP) is the first-line chemotherapy for gastric cancer (GC). The poor prognosis of GC patients is partially due to the development of CDDP resistance. Circular RNAs (circRNAs) are a subclass of noncoding RNAs that function as microRNA (miRNA) sponges. The role of circRNAs in CDDP resistance in GC has not been evaluated.MethodsRNA sequencing was used to identify the differentially expressed circRNAs between CDDP-resistant and CDDP-sensitive GC cells. qRT-PCR was used to detect the expression of circMCTP2 in GC tissues. The effects of circMCTP2 on CDDP resistance were investigated in vitro and in vivo. Pull-down assays and luciferase reporter assays were performed to confirm the interactions among circMCTP2, miR-99a-5p, and myotubularin-related protein 3 (MTMR3). The protein expression levels of MTMR3 were detected by western blotting. Autophagy was evaluated by confocal microscopy and transmission electron microscopy (TEM).ResultsCircMCTP2 was downregulated in CDDP-resistant GC cells and tissues compared to CDDP-sensitive GC cells and tissues. A high level of circMCTP2 was found to be a favorable factor for the prognosis of patients with GC. CircMCTP2 inhibited proliferation while promoting apoptosis of CDDP-resistant GC cells in response to CDDP treatment. CircMCTP2 was also found to reduce autophagy in CDDP-resistant GC cells. MiR-99a-5p was verified to be sponged by circMCTP2. Inhibition of miR-99a-5p could sensitize GC cells to CDDP. MTMR3 was confirmed to be a direct target of miR-99a-5p. Knockdown of MTMR3 reversed the effects of circMCTP2 on the proliferation, apoptosis and autophagy of CDDP-resistant GC cells. CircMCTP2 was also confirmed to inhibit CDDP resistance in vivo in a nude mouse xenograft model.ConclusionsCircMCTP2 sensitizes GC to CDDP through the upregulation of MTMR3 by sponging miR-99a-5p. Overexpression of CircMCTP2 could be a new therapeutic strategy for counteracting CDDP resistance in GC.

Circular RNA TMEM87A promotes cell proliferation and metastasis of gastric cancer by elevating ULK1 via sponging miR-142-5p.

Circular RNAs (circRNAs) act as vital regulators of gene expression in a variety of cancers. However, the role of circRNAs in gastric cancer (GC) remains largely unexplored. Herein, we identified that circTMEM87A sponges miR-142-5p to promote GC progression through up-regulating ULK1 expression. The expression of circTMEM87A in GC was determined by RNA sequencing and quantitative real-time PCR (qRT-PCR). The effects of knockdown or exogenous expression of circTMEM87A on GC cell phenotypes were evaluated both in vitro and in vivo. The interacting miRNA of circTMEM87A was predicted by bioinformatics and confirmed by RNA pull-down, dual-luciferase reporter assay and fluorescence in situ hybridization (FISH). The mechanism by which circTMEM87A/miR-142-5p/ULK1 axis promotes GC was determined by western blot, GFP/mRFP-LC3 puncta analysis, transmission electron microscope (TEM). CircTMEM87A was dramatically elevated in GC tissues and cell lines, and high circTMEM87A expression was closely correlated with poor prognosis of GC patients. Knockdown of circTMEM87A suppressed cell growth, migration, invasion and induced apoptosis in vitro, as well as inhibited GC tumorigenicity and lung metastasis potential in vivo. Meanwhile, circTMEM87A overexpression had the opposite effects. Furthermore, we demonstrated that circTMEM87A could act as a sponge of miR-142-5p to regulate ULK1 expression and GC progression. Our findings suggest that circTMEM87A functions as an oncogene through the miR-142-5p/ULK1 axis in GC. CircTMEM87A might be a prognostic biomarker as well as a promising therapeutic target for GC.

TNFAIP6 promotes invasion and metastasis of gastric cancer and indicates poor prognosis of patients

TNFα-stimulated gene-6 (TNFAIP6) plays an important role in the prognosis of many tumors. Our objective was to investigate the clinical and prognostic value of TNFAIP6 expression in gastric cancer (GC) patients. Here, we investigated the expression of TNFAIP6 in GC tissues using western blotting and immunohistochemistry and the association between TNFAIP6 expression and the prognosis and clinicopathological parameters of GC patients. Our results revealed that the expression of TNFAIP6 was higher in GC tissue than in normal gastric tissue, and the levels were positively correlated with the depth of tumor invasion (P = 0.010), tumors with lymph node metastasis (P = 0.000) and TNM stage (P = 0.003) of GC patients. Moreover, the results revealed that patients with high TNFAIP6 expression exhibited poorer overall survival than those with low TNFAIP6 expression (P = 0.037). Additionally, knockdown of TNFAIP6 inhibited the proliferation, invasion and metastasis of GC cells in vitro. High TNFAIP6 expression was associated with the depth of tumor invasion, lymph node metastasis, TNM stage and poor prognosis of GC patients, suggesting that TNFAIP6 may serve as a novel indicator of the prognosis and as a treatment target of GC.

LncRNA RPPH1 predicts poor prognosis and regulates cell proliferation and migration by repressing P21 expression in gastric cancer.

The purpose of this study was to explore the expression and biological functions of long non-coding ribonucleic acid (lncRNA) ribonuclease P RNA component H1 (RPPH1) in gastric cancer (GC), and to analyze the correlations of lncRNA expression with the clinical features and prognosis of GC patients. The relative expression of RPPH1 in tissue specimens from 60 GC patients was measured via quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR), and the correlations of RPPH1 expression with tumor-node-metastasis (TNM) stage, lymph node metastasis, etc. in GC patients were analyzed. Then, qRT-PCR was performed to detect the relative expression level of RPPH1 in GC cells. Moreover, colony formation assay, 5-Ethynyl-2'-deoxyuridine (EdU) staining, wound-healing assay, and transwell assay were employed to investigate the influence of RPPH1 on GC cell functions. After interfering in the expression of RPPH1, the changes in p21 (CDKN1A, cyclin dependent kinase inhibitor 1A) expression were determined through qRT-PCR and Western blotting. It was shown in qRT-PCR assay results that the expression of RPPH1 was upregulated in 60 cases of GC tissues. Statistical analysis revealed that RPPH1 expression was positively correlated with the TNM stage, lymph node metastasis, and infiltration depth in GC patients. Besides, highly expressed lncRNA RPPH1 suggested poor prognosis of GC patients. Based on the results of qRT-PCR assay, the expression of RPPH1 in GC cells was upregulated. After interfering in RPPH1 expression, both colony formation assay and EdU staining indicated that the proliferative capacity of GC cells was repressed. Furthermore, it was manifested in the results of wound-healing and transwell assays that the migratory and invasive abilities of GC cells were weakened. Finally, the qRT-PCR and Western blotting assay results demonstrated that p21 expression was upregulated after interfering in the expression of RPPH1 in GC cells. The expression of lncRNA RPPH1 is upregulated in GC, suggesting that the prognosis of the patients is poor. Highly expressed RPPH1 promotes the proliferation and metastasis of GC cells by regulating p21 expression.

GALNT10 promotes the proliferation and metastatic ability of gastric cancer and reduces 5-fluorouracil sensitivity by activating HOXD13.

To investigate the expression and potential mechanism of GALNT10 in gastric cancer (GC). A total of 60 cases of GC tissues, as well as normal tissues were collected. The total RNA of GC specimens and cells were extracted by TRIzol method and the level of GALNT10 was examined by quantitative real-time polymerase chain reaction (qRT-PCR). In addition, the relationship between GALNT10 and clinical parameters and prognosis of GC patients was analyzed. Subsequently, Lentivirus was used to construct GALNT10 knockdown GC cell lines, and cell counting kit-8 (CCK-8) and transwell assays were applied to analyze the influence of GALNT10 on GC cell function. Bioinformatics and Luciferase assay was used to evaluate the relationship between GALNT10 and HOXD13. Furthermore, 5-fluorouracil (5-Fu)-resistant cells were used to detect the relationship between GALNT10 and 5-Fu sensitivity of GC cells. qRT-PCR results revealed that GALNT10 level was markedly increased in tissues, as well as cell lines of GC. Statistical analysis suggested that GALNT10 expression was in close relation with the incidence of lymph node and distant metastasis along with poor prognosis in GC patients, but not with other indicators. CCK-8 and transwell migration experiment results indicated that GALNT10 silencing can inhibit the proliferative and migration ability of GC cells. Western blot results displayed that the HOXD13 level was remarkably decreased after GALNT10 knocking down. In addition, Luciferase gene assay indicated that GALNT10 could bind to HOXD13. Further rescue experiments showed that HOXD13overexpression can synergistically reverse the inhibitory effect of GALNT10 knockdown on GC cell proliferative and migration ability, which further demonstrated that GALNT10 could promote GC cell metastasis ability and reduce the sensitivity to 5-Fu by regulating HOXD13. GALNT10 could regulate the proliferative and migration ability of GC cells and reduce the sensitivity to 5-Fu by enhancing the expression of HOXD13. Therefore, GALNT10 was expected to be a new therapeutic target for diagnosis of 5-fluorouracil resistance in GC.

Clinical significance of peripheral blood-derived inflammation markers in advanced gastric cancer after radical resection

BackgroundThe prognostic significance of peripheral blood-derived inflammation markers in patients with gastric cancer (GC) has not been elucidated. This study aimed to investigate the relationship between systemic inflammatory markers and GC prognosis.MethodsA prospective observational cohort study involving 598 patients was conducted to analyze the prognosis of GC based on systemic inflammatory markers. The following peripheral blood-derived inflammation markers were evaluated: the neutrophil-lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), systemic immune-inflammation index (SII), C-reactive protein/albumin (CRP/Alb) ratio, Glasgow Prognostic Score (GPS), modified Glasgow Prognostic Score (mGPS), prognostic nutrition index (PNI), and prognostic index (PI). The receiver operating characteristics (ROC) curve and the Youden index were used to determine the optimal cutoff values. Univariate and multivariate analysis of prognostic factors was conducted accordingly.ResultsThe optimal cutoff values of the PNI, fibrinogen, NLR, PLR, SII, and CRP/Alb were 49.5, 397 ng/dl, 2.5, 154, 556, and 0.05, respectively. Multivariate analysis showed that age, PLR, TNM stage, and chemotherapy were the independent prognostic factors for advanced gastric cancer (AGC). Adjuvant chemotherapy improved the long-term prognosis of patients with PLR ≥154, but chemotherapy had no significant effect on the survival of patients with PLR < 154.ConclusionsOur findings show that higher PLR (≥154) is an independent risk factor for poor prognosis in GC patients. Besides, PLR can predict adjuvant chemotherapy (oxaliplatin/5-fluorouracil combination) response in patients with GC after surgery.

The role of TRPV1 ion channels in the suppression of gastric cancer development

BackgroundAlthough the aberrant expression and function of most Ca2+-permeable channels are known to promote gastrointestinal tumors, the association between transient receptor potential vanilloid receptor 1 (TRPV1) channels and gastric cancer (GC) has not yet been explored. Herein, we sought to determine the role of TRPV1 channels in the development of GC and to elucidate the underlying molecular mechanisms involved therein.MethodsImmunohistochemistry, qPCR, Western blot, immunofluorescence assays were used to detect the mRNA and protein expression of TRPV1 in GC cells and tissues, and the clinical significance of TRPV1 in GC was also studied by clinicopathologic analysis. CCK8, colony formation, flow cytometry assays were used to detect the proliferation and survival of GC cells, while transwell assay was used to detect migration and invasion of GC cells in vitro. Tumor xenograft and peritoneal dissemination assays in nude mice were used to examine the role of TRPV1 in GC development in vivo.ResultsTRPV1 expression was significantly downregulated in human primary GC tissues compared to their adjacent tissues. The decreased expression of TRPV1 proteins in GC tissues was positively correlated with tumor size, histological grade, lymphatic metastasis, clinical stage, and was strongly correlated with poor prognosis of GC patients. Moreover, the expression of TRPV1 was closely correlated with Ki67, VEGFR, and E-cadherin, all of which are the well-known cancer markers for proliferation and metastasis. TRPV1 proteins were predominately expressed on the plasma membrane in several GC cell lines. TRPV1 overexpression blocked cell cycle at G1 phase to inhibit GC cell proliferation and attenuated migration and invasion of GC cells in vitro, but TRPV1 knockdown increased these parameters. TRPV1 significantly reduced gastric tumor size, number and peritoneal dissemination in vivo. Mechanistically, TRPV1 overexpression in GC cells increased [Ca2+]i, activated CaMKKβ and AMPK phosphorylation, and decreased expression of cyclin D1 and MMP2, while TRPV1 knockdown induced the opposite effects.ConclusionsTRPV1 uniquely suppresses GC development through a novel Ca2+/CaMKKβ/AMPK pathway and its downregulation is correlated with poor survival of human GC patients. Thus, TRPV1 upregulation and its downstream signaling may represent a promising target for GC prevention and therapy.

Enolase 1 regulates stem cell-like properties in gastric cancer cells by stimulating glycolysis

Recent studies have demonstrated that gastric cancer stem cells (CSCs) are a rare sub-group of gastric cancer (GC) cells and have an important role in promoting the tumor growth and progression of GC. In the present study, we demonstrated that the glycolytic enzyme Enolase 1 (ENO1) was involved in the regulation of the stem cell-like characteristics of GC cells, as compared to the parental cell lines PAMC-82 and SNU16, the expression of ENO1 in spheroids markedly increased. We then observed that ENO1 could enhance stem cell-like characteristics, including self-renewal capacity, cell invasion and migration, chemoresistance, and even the tumorigenicity of GC cells. ENO1 is known as an enzyme that is involved in glycolysis, but our results showed that ENO1 could markedly promote the glycolytic activity of cells. Furthermore, inhibiting glycolysis activity using 2-deoxy-d-glucose treatment significantly reduced the stemness of GC cells. Therefore, ENO1 could improve the stemness of CSCs by enhancing the cells’ glycolysis. Subsequently, to further confirm our results, we found that the inhibition of ENO1 using AP-III-a4 (ENOblock) could reduce the stemness of GC cells to a similar extent as the knockdown of ENO1 by shRNA. Finally, increased expression of ENO1 was related to poor prognosis in GC patients. Taken together, our results demonstrated that ENO1 is a significant biomarker associated with the stemness of GC cells.

The miRNA, miR-125b, Inhibited Invasion and Metastasis of Gastric-Cancer Cells by Triggering the STAT3 Signaling Pathway.

ObjectiveTo investigate the function and the mechanism of miR-125b in the invasion and metastasis of gastric cancer and provide experimental basis for finding and developing new therapeutic strategies for gastric cancer.MethodsThe difference of miR-125b expression in gastric cancer tissues and adjacent tissues was detected by qRT-PCR. The same test was performed in different gastric cancer cell lines. The effect of miR-125b on SGC-7901 and BGC-823 gastric cancer cell viability was examined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Transwell assay was used to detect the effect of miR-125b on invasion and metastasis of gastric cancer cells. The target gene STAT3 of miR-125b was identified and validated by dual luciferase reporter assay. Western blot assay and immunofluorescence staining were used to detect the effect of miR-125b on the expression and distribution of STAT3 protein. The inhibitor and activator of STAT3 were used to confirm the effect of STAT3 on invasion and metastasis of gastric cancer cells. Peritoneal metastasis experiment and IHC were used to study the inhibitory effect of miR-125b on the metastasis of gastric cancer in vivo.ResultsThe results of qRT-PCR showed that 125b expression was significantly lower in gastric cancer than in adjacent tissues, which indicated poor prognosis for gastric-cancer patients. Furthermore, two gastric-cancer cell lines, SGC-7901 and BGC-823, exhibited lower miR-125b levels than the normal cell line HEK293. After treatment with miR-125b mimics, cell proliferation was markedly inhibited. Meanwhile, the invasion and metastasis of gastric cancer cells were also inhibited after treated with miR-125b mimics. We also identified the signal transducer and activator of transcription 3 (STAT3) as a potential target of miR-125b based on patient data from The Cancer Genome Atlas (TCGA). Dual luciferase assays revealed that miR-125b directly inhibited STAT3 by binding to its 3′-untranslated region (UTR). Immunofluorescence assay showed that miR-125b could affect the subcellular distribution of STAT3. Moreover, treatment with miR-125b mimics or stattic inhibited invasion and migration in the gastric cancer cell lines, and IL-6 could reverse the inhibitory effect. Finally, nude mice xenografted with gastric-cancer cells expressing miR-125b mimics exhibited smaller tumors and lower transfer rates than mice engrafted with control group cells.ConclusionThese data suggested that miR-125b inhibited invasion and metastasis in gastric cancer by inhibiting STAT3; therefore, miR-125b and STAT3 could be potential therapeutic targets in the treatment of gastric cancer.

The calcium pump PMCA4 prevents epithelial-mesenchymal transition by inhibiting NFATc1-ZEB1 pathway in gastric cancer

Epithelial-mesenchymal transition (EMT) is considered as the key mechanism involved in cancer metastasis. Several studies showed that various cell membrane calcium channels play different roles in cancer metastasis. In the present study, the potential role of ATPase plasma membrane Ca2+ transporting 4 (PMCA4) in regulating EMT in gastric cancer (GC) was investigated. GC patients who underwent radical surgery were enrolled in this study. In vitro human GC cell lines MKN45 and NCI-N87 were used, and MKN45 cells were injected in nude mice to evaluate tumor development. Our results showed that low PMCA4 expression was associated with advanced TNM stage and poor prognosis in GC patients. Knockdown of PMCA4 suppressed E-cadherin, grainyhead like 2 (GRHL2) and ovo-like 1 (OVOL1) expression, up-regulated vimentin expression, increased migration and invasion ability, and promoted the resistance to cytotoxic drug. Furthermore, GC cells displayed an elongated fibroblastoid morphology when PMCA4 was knockdown. PMCA4 overexpression resulted in an up-regulated E-cadherin expression and decreased migration and invasion ability. In vivo metastasis assay showed that PMCA4 overexpression resulted in a decreased incidence of lung metastasis. PMCA4 inhibition increased ZEB1 expression and nuclear accumulation of nuclear factor of activated T-cell isoform c1 (NFATc1). EMT induced by PMCA4 inhibition could be prevented by the knockdown of NFATc1 or ZEB1. In addition, cyclosporine A prevented EMT induced by PMCA4 inhibition by suppressing the NFATc1-ZEB1 pathway. Our data identified a novel mechanism in the regulation of EMT in GC, and provided a novel target in the treatment of EMT subtype in GC.

Mining TCGA database for genes of prognostic value in gastric cancer microenvironment.

Gastric cancer (GC) is the sixth most common malignancy and the third leading cause of cancer‐related death worldwide. Emerging evidence suggests that tumour microenvironment cells play a vital role in the development and prognosis of GC. To investigate the possible effect of stromal scores and immune scores on the overall survival (OS) on the GC patients, we divided GC patients into ‘high’ and ‘low’ groups based on their stromal and immune scores, and found differentially expressed genes related to prognosis of GC patients. Functional enrichment analysis and GSVA further revealed that focal adhesion and ECM‐receptor interaction are associated with GC patients' survival. Finally, we analysed the effects of genes commonly involved in focal adhesion and ECM‐receptor interaction on GC patients' survival and validated our results in another GC cohort from GEO data sets. In conclusion, we obtained a list of tumour microenvironment‐related genes that predict poor prognosis in GC patients.

Circular RNA circFGD4 suppresses gastric cancer progression via modulating miR-532-3p/APC/β-catenin signalling pathway.

Mounting evidence has displayed critical roles of circular RNAs (circRNAs) in multiple cancers. The underlying mechanisms by which circFGD4 contributed to gastric cancer (GC) are still unclear. The levels and clinical values of circFGD4 in GC patients were detected and analysed by quantitative real-time PCR. The biological roles of circFGD4 in GC were assessed in vitro and in vivo experiments. Dual-luciferase reporter, fluorescence in situ hybridization, RNA immunoprecipitation, biotin-coupled RNA pull-down, and TOP/Flash and FOP/Flash reporter gene assays were employed to evaluate the effects of circFGD4 on miR-532-3p-mediated adenomatous polyposis coli (APC)/β-catenin signalling in GC cells. circFGD4 expression was down-regulated the most in human GC tissues and cell lines. Low expression of circFGD4 was correlated with poor tumour differentiation, lymphatic metastasis, and poor prognosis of GC patients. circFGD4 suppressed GC cell viability, colony formation, migration, induced epithelial-mesenchymal transition (EMT), and tumorigenesis and metastasis in vivo. Next, we validated that circFGD4 acted as a sponge of miR-532-3p to relieve the tumour-promoting effects of miR-532-3p on its target APC. The mechanistic analysis demonstrated that the circFGD4 suppressed GC cell viability, migration, and EMT by modulating the miR-532-3p/APC axis to inactivate the β-catenin signalling. circFGD4 suppressed GC progression through sponging miR-532-3p and enhancing APC expression to inactivate the β-catenin signalling. Thus circFGD4 provides a novel potential biomarker and valuable therapeutic strategy for GC.

Cancer-associated fibroblasts promote the migration and invasion of gastric cancer cells via activating IL-17a/JAK2/STAT3 signaling.

Cancer-associated fibroblasts (CAFs), as the activated stroma cells, contribute to tumor progression via the release of cytokines, growth factors, and hormones. However, neither the factors produced by CAFs nor the molecular mechanisms were illuminated very well in gastric cancer (GC). Immunohistochemical staining of alpha-smooth muscle actin (α-SMA) was applied to examine the number of CAFs in GC samples from 227 patients. ELISA and qRT-PCR were performed to detect the expression of interleukin 17a (IL-17a). The migration and invasion of GC cells were determined by the Transwell assay. The expressions of JAK2, STAT3, MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured by western blotting. IL-17a was blocked with a polyclonal antibody, and JAK2/STAT3 signaling pathway was blocked by a specific inhibitor AG490. High CAFs in GC tissues were positively correlated with advanced TNM stage and perineural invasion. Furthermore, GC patients with high CAFs in tumor tissues had an obvious worse disease-free survival (DFS) and disease-special survival (DSS). Multivariate analysis showed that high CAFs in GC tissues were an independent risk factor for DFS and DSS. CAFs expressed IL-17a significantly after GC cell co-culture. CAFs markedly enhanced the migration and invasion abilities of AGS and SGC-7901 cells. Moreover, CAFs co-culture resulted in increased levels of MMP2/9, reduced expressions of TIMP1/2, and activation of the JAK2/STAT3 signaling pathway in the GC cells. IL-17a neutralizing antibody or JAK2 inhibitor AG490 can significantly inhibit the effects of CAFs on the migration, invasion, MMP2/9, TIMP1/2, and JAK2/STAT3 pathways of GC cells. CAFs correlated with unfavorable clinical features and poor prognosis of GC patients. CAFs secreted IL-17a, which promoted the migration and invasion of GC cells through activating JAK2/STAT3 signaling. These results may identify IL-17a as a promising prognostic marker and therapeutic target of GC.

Circular RNA hsa_circ_103809 promotes cell migration and invasion of gastric cancer cells by binding to microRNA-101-3p.

Studies have found that hsa_circ_103809, a newly discovered circRNA in recent years, can serve as an oncogene involved in the progression of hepatocellular carcinoma. However, its role in gastric cancer (GCa) remains elusive. The aim of this study was to reveal the molecular mechanism of hsa_circ_103809 affecting the process of GCa, thus providing new ideas for its treatment. Hsa_circ_103809 expression in GCa and adjacent tissues specimens were studied by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) analysis, and its effect on the prognosis of GCa patients was analyzed. In GCa cells lines, hsa_circ_103809 was knocked down by small interfering RNA, and GCa cell metastasis ability was detected by cell wound healing test and transwell assay. Finally, the potential target gene of hsa_circ_103809 was predicted through bioinformatics website and verified by Luciferase assay. Hsa_circ_103809 showed an increased expression both in GCa tissues and cell lines, predicting a poor prognosis of GCa patients. Meanwhile, the invasive and migration capacities of GCa cells were remarkably reduced after the knockdown of hsa_circ_103809. Bioinformatics website predicted that there existed binding sites of hsa_circ_103809 on microRNA-101-3p, and Luciferase assay verified that hsa_circ_103809 can adsorb microRNA-101-3p. In GCa tissues, qPCR detected a significantly reduced expression of microRNA-101-3p, which was negatively correlated with that of hsa_circ_103809. In addition, the knockdown of hsa_circ_103809 enhanced microRNA-101-3p expression in GCa cell lines. Subsequent in vitro experiments further detected that the overexpression of hsa_circ_103809 partially reversed the inhibitory effect of microRNA-101-3p overexpression on GCa cell migration ability and invasiveness. Hsa_circ_103809, highly expressed in GCa, may promote the migration capacity of GCa cells by adsorbing microRNA-101-3p and thus become a new therapeutic target for GCa.

Overexpressed circ-RPL15 predicts poor survival and promotes the progression of gastric cancer via regulating miR-502-3p/OLFM4/STAT3 pathway

BackgroundIncreasing studies have revealed that circular RNAs (circRNAs) contribute to gastric cancer (GC) progression. The circular RNA ribosomal protein L15 (circ-RPL15) is involved in chronic lymphocytic leukemia. However, its expression and functions in GC remain elusive. MethodsThe expression of circ-RPL15 in human GC tissues and adjacent normal tissues, human gastric cancer cell lines (MGC-803, BGC-823, MGN-28, SGC-7901, AGS) and normal gastric mucosal epithelial cell line (GES-1) were detected by RT-PCR. The relationship between circ-RPL15 level and clinical-pathological indicators were also analyzed. Gain- of function experiments of circ-RPL15 and miR-502-3p were conducted to verify their roles in mediating GC cell proliferation, apoptosis and metastasis. Also, the downstream mechanisms of circ-RPL15 were predicted by bioinformatics analysis, and the interactions between circ-RPL15 and miR-502-3p, miR-502-3p and OLFM4 were verified by dual luciferase reporter gene assay and RNA FISH. Resultscirc-RPL15 was upregulated in GC tissues and cell lines, and the overexpressed circ-RPL15 was correlated with poorer survival of GC patients. Functionally, circ-RPL15 upregulation distinctly promoted the proliferation, migration and invasion of GC cells and inhibited apoptosis. Mechanistically, circ-RPL15 functioned as a competitive endogenous RNA via sponging miR-502-3p and activated OLFM4/STAT3 pathway. Conclusioncirc-RPL15 promotes GC progression and predicts poor prognosis of GC patients, and regulates the malignant phenotypes of GC cells by mediating the miR-502-3p/OLFM4/STAT3 axis.

CircCYFIP2 Acts as a Sponge of miR-1205 and Affects the Expression of Its Target Gene E2F1 to Regulate Gastric Cancer Metastasis

Accumulating evidence suggested that circular RNAs (circRNAs) play critical roles in the initiation and progression of malignant cancers. However, the roles of circRNAs in gastric cancer (GC) remain largely unknown. In the present study, we investigated the expression of circRNAs in 5 GC tissues with metastasis and 5 GC tissues without metastasis by microarray analysis. We focused on hsa_circ_0003506, which was spliced from CYFIP2 gene located at chr5:156786012–156788606 and finally formed a sense-overlapping circular transcript of 366 nt, and thus we named it circCYFIP2. circCYFIP2 was found to be significantly upregulated in GC tissues and cell lines. High expression of circCYFIP2 was associated with metastasis and poor prognosis of GC patients. Function assays revealed that overexpression or knockdown of circCYFIP2 significantly enhanced or reduced GC cell proliferation and invasion abilities. In mechanism, we found that circCYFIP2 might serve as a competing endogenous RNA (ceRNA) of microRNA-1205 (miR-1205) in GC progression. Besides, E2F1 was found to be a target of miR-1205. Collectively, our findings suggested that circCYFIP2 might serve as an oncogenic circRNA to promote GC progression via the miR-1205/E2F1 axis, which provided a potential therapeutic target for the treatment of GC.

Prognostic Significance of PD-1, PD-L1 and CD8 Gene Expression Levels in Gastric Cancer

Introduction: Anti-programmed cell death 1 (PD-1) therapies have shown promising clinical activity against gastric cancer (GC). We evaluated the clinical significance of immune-related gene expression in GC tissues to better understand the tumor immune microenvironment. Methods: PD-1, PD-1 ligand 1 (PD-L1) and CD8 mRNA levels and clinicopathological factors, including survival, were examined by quantitative RT-PCR in 155 GC patients who underwent surgery. PD-1 and PD-L1 expression in tumor tissue from 24 GC patients was investigated by immunohistochemical analysis. Results: PD-1, PD-L1 and CD8 mRNA levels were significantly lower in tumor tissue than in normal tissue (p < 0.0001, p < 0.05, and p < 0.0001). GC patients with low PD-1, PD-L1 and CD8 mRNA levels had significantly poorer overall survival (OS) than those with high PD-1, PD-L1 and CD8 mRNA levels, respectively (p < 0.001, p < 0.01 and p < 0.05). Low PD-1, PD-L1 and CD8 mRNA levels were more significantly associated with poor prognosis in undifferentiated-type GC patients than in differentiated-type GC patients (PD-1: differentiated p = 0.0071 vs. undifferentiated p = 0.0024; PD-L1: p = 0.6527 vs. p < 0.0001; CD8: p = 0.4465 vs. p < 0.05). Multivariate analysis showed that lymph node metastasis, peritoneal dissemination, distant metastasis, low PD-1 mRNA levels and low CD8 mRNA levels were independent prognostic factors for worse OS (low PD-1 mRNA level: OR 2.16, 95% CI 1.10–4.58, p < 0.05; low CD8 mRNA level: OR 2.55, 95% CI 1.12–6.90, p < 0.05). PD-1 and PD-L1 mRNA levels in immune cells were significantly associated with PD-1 and PD-L1 protein levels (both p < 0.05), respectively. Conclusions: PD-1, PD-L1 and CD8 mRNA levels may reflect antitumor immunity in GC, and low PD-1 and CD8 mRNA levels are potential predictive biomarkers for poor prognosis in GC patients who underwent surgery.

MiRNA-339-5p suppresses the malignant development of gastric cancer via targeting ALKBH1

ObjectiveTo uncover the role of microRNA-339-5p (miRNA-339-5p) in the development of gastric cancer (GC) and its possible molecular mechanism. MethodsDifferential expressions of miRNA-339-5p in GC and adjacent normal tissues were detected. The relationship between miRNA-339-5p level and clinical features in GC patients was analyzed. Proliferative and migratory changes in BGC-823 and SGC-7901 cells overexpressing miRNA-339-5p were examined. Finally, luciferase assay and rescue experiments were conducted to explore the regulatory mechanism of miRNA-339-5p in its downstream gene ALKBH1, and their interaction in the development of GC. ResultsMiRNA-339-5p was downregulated in GC tissues. Lowly expressed miRNA-339-5p was unfavorable to prognosis in GC because of high rates of lymphatic metastasis and distant metastasis. Overexpression of miRNA-339-5p markedly reduced proliferative and migratory abilities in GC cells. ALKBH1 was identified to be the downstream gene of miRNA-339-5p. In GC tissues, ALKBH1 was upregulated and negatively correlated to miRNA-339-5p level. Overexpression of ALKBH1 was able to reverse the inhibitory effects of overexpressed miRNA-339-5p on proliferative and migratory abilities in GC. ConclusionsLowly expressed miRNA-339-5p is closely related to metastasis and poor prognosis in GC patients. MiRNA-339-5p suppresses the malignant development of GC by negatively regulating ALKBH1.

MicroRNA-216a-5p inhibits the development of gastric cancer through target combination with TCTN1.

We aimed at investigating microRNA-216a-5p expression in gastric cancer (GC) tissues and further exploring whether microRNA-216a-5p suppresses GC progression through interacting with TCTN1. microRNA-216a-5p expression in 60 pairs of GC tissues and adjacent ones was studied by quantitative real-time polymerase chain reaction (qRT-PCR) analysis, and the relationship between microRNA-216a-5p and clinical indicators as wells as prognosis of GC patients was also analyzed. At the same time, qRT-PCR was conducted to further verify microRNA-216a-5p level in GC cells. The impacts of microRNA-216a-5p on GC cell functions were evaluated using cell counting kit-8, plate cloning and Transwell experiments. Meanwhile, we studied the specific regulatory relationship between microRNA-216a-5p and TCTN1 in depth. Our data showed that microRNA-216a-5p level in GC tumor specimens was remarkably lower than that in adjacent ones. In comparison to patients in group of high microRNA-216a-5p expression, patients in group of low expression showed an increased metastasis incidence and a lower survival rate. Cell functional experiments suggested that microRNA-216a-5p mimics markedly attenuated the proliferative and migratory capacities of GC cells. Bioinformatics analysis suggest that microRNA-216a-5p can bind to its target gene TCTN1, which was confirmed by luciferase assay. Further, qPCR results revealed a negative correlation between the expression of TCTN1 and microRNA-216a-5p in GC tumor tissues. Finally, in vitro cell experiments suggested that overexpression of TCTN1 could reverse the inhibitory impact of upregulation of microRNA-216a-5p on GC cell functions. microRNA-216a-5p, abnormally lowly expressed in GC tissues, is markedly relevant to the high metastasis incidence and the poor prognosis of GC patients; in addition, microRNA-216a-5p inhibited GC's migration and proliferation capabilities through regulating TCTN1.