Human Gastric Carcinoma Tissues Research Articles

LARP1 knockdown inhibits cultured gastric carcinoma cell cycle progression and metastatic behavior.

This study aimed to clarify the role of la-related protein 1 (LARP1) in cell cycle progression and metastatic behavior of cultured gastric carcinoma (GC) cells. To do that, LARP1 expression was detected in clinical GC tissues and cell lines using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. The cell viability, apoptosis, cell cycle, migration, invasion, and cell growth were examined using a Cell Counting Kit-8, Annexin V-FITC staining, propidium iodide staining, Transwell migration and invasion assays, and colony formation assays after LARP1 knockdown. Phosphatidyl inositol 3-kinase (PI3K) and AKT1 mRNA and protein expression levels of PI3K, p-AKT1, AKT1, p-BAD, p-mTOR, and p21 in si-LARP1 transfected GC cells were determined using qRT-PCR and western blotting. Here, we've shown that LARP1 expression was upregulated in human GC tissues and KATO III cells. LARP1 knockdown inhibited GC cell proliferation, cell cycle progression, migration, invasion, and colony formation and promoted apoptosis. In si-LARP1-transfected KATO III cells, the mRNA expression levels of PI3K and AKT1, PI3K protein expression, and the p-AKT1/AKT1 ratio were significantly suppressed. p-mTOR and p-BAD were significantly decreased, whereas p21 was significantly increased in si-LARP1-transfected KATO III cells. In conclusion LARP1 knockdown induces apoptosis and inhibits cell cycle progression and metastatic behavior via PI3K/AKT1 signaling in GC cells.

TTC36 inactivation induce malignant properties via Wnt-β-catenin pathway in gastric carcinoma.

Objective: Tetratricopeptide repeat (TRP)-mediated cofactor proteins are involved in a wide range of cancers. TTC36 is little studied member of TRP subfamily. This study aimed to investigate the role of TTC36 in human gastric carcinoma (GC) and explore the potential underlying mechanisms.Methods: The analysis of TTC36 differential expression in GC was conducted using data from TCGA and a human tissue microarray. And effects of TTC36 expression on the prognosis of patients with gastric carcinoma were analyzed using the data from the GEO database. Lentivirus was transfected into the cell lines of AGS and BGC823 to construct overexpression and knocked down TTC36 cell model respectively. The effect of TTC36 expression on the growth, apoptosis and cell cycle of cells was explored in vitro. Downstream molecules were detected by western blotting. GSEA predicted signal pathway and related proteins were then detected.Results: TTC36 expression in human GC tissues was found significantly lower than that in adjacent normal tissues and closely related to clinical prognosis. The overexpression of TTC36 notably inhibited tumor progression, cell cycle G1/S transfer and increased apoptosis in AGS cells. Conversely, the opposite effects were observed when TTC36 was suppressed in BGC823 cells. The expression of cleaved caspase3, Survivin, cyclin D1 and c-Myc were consistent with the phenotype in TTC36 operated GC cell lines. Intriguingly, GSEA analysis predicted Wnt-β-catenin pathway involved in TTC36 induced effects in GC cells, expression of β-catenin and downstream molecules such as TCF4, c-jun and pAKT were found negative related to TTC36 expression in GC cells. Notably, treatment with the Wnt/β-catenin inhibitor XAV939 dramatically attenuated the effects of TTC36 in GC cells.Conclusion: These results signify a critical role for TTC36 as a tumor suppressor in gastric carcinoma via regulating Wnt-β-catenin pathway.

Circular RNA hsa-circ-0007766 modulates the progression of Gastric Carcinoma via miR-1233-3p/GDF15 axis.

Circular RNAs (circRNAs), a new kind of non-coding RNAs, have gradually been proved to be critical regulators of gene expression; however, the underlying mechanisms still need to be elaborated. In the present study, we investigated the role of hsa-circ-0007766 in gastric carcinoma (GC). Quantitative real-time PCR was applied to detect the differential expression levels of circRNA, miRNAs, and mRNAs in human tissues and specific cell lines. GC cell lines were transiently transfected with siRNA. Then the proliferation, migration, and invasion assays were performed to evaluate the effect of hsa-circ-0007766 in GC cell lines. Fluorescence in situ hybridization, RNA pulldown assay was used to confirm the location of hsa-circ-0007766 and its relationship with miR-1233-3p. Luciferase reporter assay was then conducted to verify the interaction between miR-1233-3p and GDF15. Interestingly, we found that hsa-circ-0007766 was highly expressed in human GC tissues and GC cell lines. Knock-down of hsa-circ-0007766 inhibited cell proliferation, migration, invasion, and down-regulated the expression of GDF15. Moreover, hsa-circ-0007766 was identified as a sponge of miR-1233-3p, which could target gene GDF15 to regulate the progression of GC. Finally, hsa-circ-0007766 was evaluated to be a valuable diagnostic marker with a sensitivity of 53.33% and specificity of 83.33% by ROC analysis. This study unveils a mechanism by which hsa-circ-0007766 regulates GDF15 via hsa-circ-0007766/miR-1233-3p/GDF15 axis, which may provide new insight for GC therapeutic strategies.

MiR-135b-5p promotes viability, proliferation, migration and invasion of gastric cancer cells by targeting Krüppel-like factor 4 (KLF4).

IntroductionThe expression of MiR-135b-5p was up-regulated while Krüppel-like factor 4 (KLF4) expression was extremely low in human gastric carcinoma (GC) tissues. This study aimed to explore the role of miR-135b-5p in GC cells and its influence on various cell capacity and viability by targeting KLF4.Material and methodsThe dual-luciferase reporter assay was first performed and the target relationship between miR-135b-5p and KLF4 was confirmed. Then three GC cell lines and the human normal gastric epithelial cell line (GES1) were analyzed for the expression level of miR-135b-5p and KLF4 mRNA by RT-qPCR. The BGC-823 GC cell line was chosen for subsequent assays.ResultsThe expression of miR-135b-5p and KLF4 was manipulated via transfection. The changes of proliferation, invasion, migration, viability, cycle and apoptosis of GC cells were evaluated by MTS, colony formation assay, transwell assay, wound healing assay and flow cytometry assay, respectively. Overexpression of MiR-135b-5p enhanced viability, proliferation, invasion and migration of GC cells, increased cell viability and reduced cell apoptosis. Replenishing of KLF4 functioned oppositely.ConclusionsThe inhibitory effects of ectopic KLF4 could be attenuated by co-transfection of miR-135b-5p. Collective data suggested that miR-135b-5p has a tumor-promoting role in GC cells via downregulating KLF4. Hence, inhibition of miR-135b-5p could be valuable for treatment of gastric cancer.

MiR-324-5p reduces viability and induces apoptosis in gastric cancer cells through modulating TSPAN8.

The purpose of this study was to further clarify the role and underlying mechanism of miR-324-5p in gastric cancer. The expressions of miR-324-5p and TSPAN8 as determined by qRT-PCR or Western blot were compared between the gastric cancer tissues and normal tissues. Human gastric cancer cell line SGC-7901 was cultured and transfected with miR-324-5p mimic/inhibitor or pcDNA-TSPAN8. The cell survival was assessed by the cell viability and apoptosis. Luciferase reporter gene assays were performed to explore the interaction between miR-324-5p and TSPAN8 in SGC-7901 cells. MiR-324-5p was decreased in human gastric carcinoma tissues (n = 33), but TSPAN8 protein expression was increased in the gastric carcinoma tissues (n = 33). Moreover, miR-324-5p inhibited the viability and induced the apoptosis of gastric cancer cells in vitro. TSPAN8 is a functional target of miR-324-5p in gastric cancer. MiR-324-5p was further confirmed to reduce gastric cancer cell viability and induce apoptosis via downregulating TSPAN8 in SGC-7901 cells in vitro. Additionally, miR-324-5p overexpression markedly inhibited the tumorigenesis of gastric cancer cells in vivo, as shown by the smaller tumour volume compared with the control. This study suggested a novel, probable mechanism of miR-324-5p in gastric cancer context and revealed that miR-324-5p inhibited gastric cancer cell survival by targeting TSPAN8.

Long non-coding RNA NEAT1 promotes viability and migration of gastric cancer cell lines through up-regulation of microRNA-17.

Gastric carcinoma (GC) is a common cancer with heavy mortality and poor outcome at advanced stages and metastasis. Long non-coding RNA nuclear-enriched abundant transcript 1 (NEAT1) has been reported to be an oncogene in GC recently. However, the underlying mechanism is far from understood. We aimed to explore the role of NEAT1 in GC as well as the underlying mechanisms. The expression of NEAT1 in clinical human GC tissues and GC cell lines were assessed by quantitative reverse transcription PCR. Then, NEAT1 was non-physiologically expressed in GC cells (SGC-7901 and MKN45 cells), followed by estimation of cell viability, migration, invasion, apoptosis, activation of the phosphatidylinositol-3-kinase (PI3K)/AKT and glycogen synthase kinase 3β (GSK3β) pathways, and microRNA (miR)-17 level. Moreover, the effects of miR-17 inhibition on cell viability, migration, and activation of the PI3K/AKT and GSK3β pathways in GC cells overexpressing NEAT1 were also explored. NEAT1 was up-regulated in GC tissues and cell lines. Then, cell viability and migration of GC cells were markedly increased by NEAT1 overexpression, while the cell invasion and apoptosis were unchanged. The phosphorylated level of PI3K, AKT, and GSK3β were increased by NEAT1 overexpression. Subsequently, we found miR-17 level was positively correlated with NEAT1 expression, and NEAT1 functions through up-regulating miR-17. NEAT1 was up-regulated in GC tissues and cell lines. Its overexpression enhanced cell viability and migration through up-regulating miR-17, along with activation of the PI3K/AKT and GSK3β pathways.

MiR-182-5p improves the viability, mitosis, migration, and invasion ability of human gastric cancer cells by down-regulating RAB27A.

We investigated the effect of miR-182-5p on the viability, proliferation, invasion, and migration ability of human gastric cells by regulating the expression of RAB27A. Real-time PCR assay was used to detect the expression of miR-182-5 and RAB27A in human gastric carcinoma tissues, para-carcinoma tissues, and different cell lines. Western blotting was also used to determine the RAB27A expression in both tissues and cell lines. We chose the HGC-27 cell line as experiment subject as it demonstrated the highest miR-182-5p level. HGC-27 cells were transfected with different vectors and the cell viability, mitosis, invasion, and migration ability were measured through MTT assay, flow cytometry (FCM) analysis, Transwell assay, and wound healing assay. In comparison with the normal tissues, miR-182-5p is expressed at a higher level in gastric cancer (GC) tissues, while RAB27A is expressed at a lower level in cancerous tissues. The down-regulation of miR-182-5p and up-regulation of RAB27A can significantly decrease the viability, migration, invasion, and mitosis of HGC-27 cells. The target relationship between miR-182-5p and RAb27A was confirmed through a dual-luciferase reporter gene assay and Western blot assay. miR-182-5p enhances the viability, mitosis, migration, and invasion of human GC cells by down-regulating RAB27A.

DIMT1 overexpression correlates with progression and prognosis in gastric carcinoma

We investigated the expression of dimethyladenosine transferase 1 homolog (DIMT1) in human gastric carcinoma (GC) tissues, pericarcinoma histologically normal tissues, and normal gastric tissues and explored its clinical significance. Immunohistochemistry staining was used to detect the expression of DIMT1, and the findings were compared with clinicopathological features of patients with GC. The result also was ascertained by Western blotting. The Kaplan-Meier method and log-rank test were used to compare the overall survival rate and time in the DIMT1 low-level and high-level expression groups. Immunohistochemical staining indicated that the expression of DIMT1 in GC tissues (65/75; 86.7%) was significantly more common (P<.001) than that in pericarcinoma histologically normal tissues (14/75; 18.7%) and normal gastric tissues (2/12; 16.7%). High expression of DIMT1 correlated closely with differentiation (P=.023), invasion (P=.042), lymph node metastasis (P=.008), distant metastasis (P=.006), and TNM stage (P=.013). Western blotting showed that DIMT1 expression correlated positively with TNM stage and implied that more advanced TNM stage was accompanied by higher expression of DIMT1 (P<.001). Kaplan-Meier survival analysis showed that high DIMT1 expression correlated significantly (P<.001) with a poor prognosis. Our data suggest that DIMT1 is a useful molecular biomarker to predict tumor progression and prognosis in patients with GC.

Positive feedback loop of IL-1β/Akt/RARα/Akt signaling mediates oncogenic property of RARα in gastric carcinoma.

Abnormal expression and function of retinoic acid receptor α (RARα) have been reported to be associated with various cancers including acute promyelocytic leukemia and hepatocellular carcinoma. However, the role and the mechanism of RARα in gastric carcinoma (GC) were unknown. Here, the expression of RARα was frequently elevated in human GC tissues and cell lines, and its overexpression was closely correlated with tumor size, lymph node metastasis and clinical stages in GC patients. Moreover, RARα overexpression was related with pathological differentiation. Functionally, RARα knockdown inhibited the proliferation and metastasis of GC cells, as well as enhanced drug susceptibility both in vitro and in vivo. Additionally, RARα knockdown suppressed GC progression through regulating the expression of cell proliferation, cell cycle, invasion and drug resistance associated proteins, such as PCNA, CyclinB1, CyclinD2, CyclinE, p21, MMP9 and MDR1. Mechanistically, the above oncogenic properties of RARα in GC were closely associated with Akt signaling activation. Moreover, overexpression of RARα was induced by IL-1β/Akt signaling activation, which suggested a positive feedback loop of IL-1β/Akt/RARα/Akt signaling in GC. Taken together, we demonstrated that RARα was frequently elevated in GC and exerted oncogenic properties. It might be a potential molecular target for GC treatment.

Expression of microtubule-associated protein TPX2 in human gastric carcinoma and its prognostic significance.

BackgroundThe molecular mechanisms underlying the development and progression of gastric carcinoma remain poorly understood. The main objective of this study was to investigate the expression level of targeting protein for Xenopus kinesin-like protein 2 (TPX2) and its clinical significance in human gastric carcinoma.MethodsReal-time quantitative polymerase chain reaction (RT-PCR) and western blotting were used to determine the mRNA and protein levels of TPX2 in 20 paired gastric carcinoma tissues and the adjacent normal tissues, and the expression of TPX2 protein in 106 specimens of a gastric carcinoma tissue microarray was determined by immunohistochemistry. The associations of TPX2 expression with the clinicopathological features were analyzed, and the prognosis of gastric carcinoma patients was evaluated.ResultsThe results showed that the expression of TPX2 mRNA was significantly higher in gastric carcinoma than in the adjacent normal tissues in 20 paired samples. Western blotting analysis revealed that TPX2 protein was differentially increased in 17 of 20 specimens from primary human gastric carcinoma tissues compared with those from adjacent non-tumor tissues. Immunohistochemical staining showed that TPX2 over-expression was significantly associated with advanced age (P = 0.001) and tumor T stage (P = 0.003). In addition, TPX2 was an independent prognostic factor for overall survival (OS) in the multivariate analysis [hazard ratio (HR) 0.001; 95 % confidence interval (CI) 2.626–7.198; P = 0.001].ConclusionsTPX2 is up-regulated in gastric carcinoma and is associated with old age and tumor T stage. TPX2 may serve as a good prognostic indicator in patients with gastric carcinoma.Electronic supplementary materialThe online version of this article (doi:10.1186/s12935-016-0357-7) contains supplementary material, which is available to authorized users.

ISL1, a novel regulator of CCNB1, CCNB2 and c-MYC genes, promotes gastric cancer cell proliferation and tumor growth.

Islet-1 (ISL1) belongs to the LIM homeodomain transcription factor family, which is specifically expressed in certain tissue types only. Previously, we reported that ISL1 is aberrantly overexpressed in gastric cancer (GC). However, its role in GC is not clear. Here, we report that ISL1 is aberrantly upregulated not only in human gastric carcinoma tissues but also in some GC cell lines. Upregulated ISL1 expression enhanced xenografted gastric carcinoma development, while ISL1 knockdown inhibited GC growth in nude mice. ISL1 overexpression promoted GC cell proliferation, colony formation, and cell growth in soft agar, and facilitated cell cycle transition in GC cells, demonstrated an increase in the proportion of cells in the G2/M and S phases and a decrease in the proportion of cells in the G1 phase. Furthermore, we provide evidence that ISL1 is a novel regulator of the cyclin B1 (CCNB1), cyclin B2 (CCNB2) and c-myc (c-MYC) genes. ISL1 activated the expression of these genes in GC cells by binding to the conserved binding sites on their promoters or enhancers. The expression levels of the genes were decreased in response to ISL1 knockdown. Therefore, ISL1 may serve as a potential therapeutic target in GC.

Resistance to the c-Met inhibitor KRC-108 induces the epithelial transition of gastric cancer cells.

Investigation of the mechanisms of resistance to targeted therapies is essential as resistance acquired during treatment may lead to relapse or refractoriness to the therapy. Our previous study identified the small molecule KRC-108 as a result of efforts to find an anticancer agent with c-Met-inhibitory activity. In the present study, the changes accompanying resistance to KRC-108 were investigated in the gastric cancer cell line MKN-45 and its KRC-108-resistant clones by western blot and immunofluorescence analyses. Increased expression of the c-Met protein was observed in KRC-108-resistant cells compared with that of the parental cells, and the phosphorylation of c-Met also increased in cell lines resistant to KRC-108. Resistance to the c-Met inhibitor was associated with cell morphological changes: MKN-45 parental cells, which had a round and poorly differentiated morphology, were altered to exhibit an epithelial cell-like phenotype in KRC-108-resistant clones. Consistent with the transition to an epithelial morphology, the expression of E-cadherin was increased in resistant cells. Using immunoprecipitation, an interaction between E-cadherin and the c-Met protein was observed in the KRC-108-resistant cells. Immunohistochemical analysis of human gastric carcinoma tissues revealed the co-expression of E-cadherin and c-Met. These results suggest that the epithelial transition in KRC-108-resistant cells is mediated by recruiting E-cadherin to c-Met protein. Thus, the present study identified a mechanism used by cancer cells to confer resistance to anticancer agents.

Abstract 2716: Epstein-Barr virus-encoded BARF1 downregulates SMAD4 and increases miR-146a in gastric carcinoma cells

Abstract Recently, molecular analytic data from ‘The Cancer Genome Atlas’ (TCGA) (http://www.cbioportal.org) has re-confirmed that Epstein-Barr virus (EBV)-infected gastric carcinoma is a specialized subset of gastric carcinomas. However, viral oncogene has not yet been established in gastric carcinomas. Several reports have suggested that EBV-encoded BARF1 may be a putative viral oncogene in gastric carcinoma. The aim of this study was to investigate alterations of cellular microRNA and cellular protein by BARF1 in gastric carcinoma cells. We cloned BARF1 from naturally EBV-infected gastric carcinoma cell line, and transfected BARF1 into EBV-negative gastric carcinoma cells, thus produced a stable cell line of BARF1-transfected gastric carcinoma cells. BARF1-transfected gastric carcinoma cells revealed significantly increased cellular proliferation than its original cells. The MicroRNA array (Agilent release 16.0) data and Taqman RT-PCR results showed that cellular miR-146a was highly expressed in BARF1-transfected gastric carcinoma cells, comparing to that in original cells. In BARF1-transfected gastric carcinoma cells, transfection with BARF1-siRNA offset the increment effect of miR-146. Using bioinformatics analyses for miR-146a target (RNA hybrid 2.2 and TargetScan 5.2 sites), we found that miR-146a target seed sequence existed in the 3′ UTR of SMAD4 mRNA. The Western blot assay demonstrated that SMAD4 was remarkably reduced by BARF1 transfection. When immunohistochemistry for SMAD4 was performed on 343 cases of surgically resected, human gastric carcinoma tissues, 32 (9%) EBV-infected gastric carcinoma group disclosed more frequent loss of SMAD4 than EBV-negative group. In conclusion, EBV-encoded BARF1 could promote proliferation of gastric carcinoma cells, thereby contributing to EBV-induced cancer progression, in which SMAD4 downregulation, probably through miR-146a increase, may be entailed. Citation Format: Dong Ha Kim, Chan Jin Yoon, Jin, Kyung Rho, Jaap M. Middeldorp, Jun Hee Woo, Mee Soo Chang. Epstein-Barr virus-encoded BARF1 downregulates SMAD4 and increases miR-146a in gastric carcinoma cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2716. doi:10.1158/1538-7445.AM2015-2716

An abnormally high expression of ISL-1 represents a potential prognostic factor in gastric cancer.

Insulin gene enhancer binding protein-1 (ISL-1) is a transcription factor involved in development of the heart, motor neurons, and pancreas. Our previous study indicated that ISL-1 was overexpressed in gastric cancer but not in other gastrointestinal tumors. However, no immunohistochemical or clinicopathological studies of ISL-1 in gastric carcinoma have been performed. The aim of this study was to determine the expression and prognostic value of ISL-1 in gastric carcinoma. A nude mouse xenograft model was established to study the role of ISL-1 on cancer genesis and development in vivo. Overexpression of ISL-1 significantly enhanced the tumorigenicity of NIH3T3 cells in vivo. ISL-1 expression was evaluated using immunohistochemistry in 456 human gastric carcinoma and normal tissues. ISL-1 was significantly overexpressed in gastric adenocarcinoma compared with normal gastric tissues. ISL-1 expression was significantly associated with depth of invasion, lymph node metastasis, TNM stage, and histological grade (P < .05, χ(2) test). Positive ISL-1 expression was associated with poorer 5-year overall survival in gastric cancer (P = .001, log-rank test). Multivariate Cox regression analysis demonstrated that ISL-1 expression (P = .047) could be an independent prognostic factor for overall survival in gastric carcinoma. This study suggests that ISL-1 may be a useful prognostic biomarker and may represent a novel therapeutic target for gastric adenocarcinoma.

CD40 expression and its prognostic significance in human gastric carcinoma.

This study aimed to detect the relationship between CD40 (protein and mRNA) expression and human gastric cancer and to determine the prognostic significance of CD40 in gastric cancer patients. We collected 128 cases of gastric cancer specimens, and the expression of CD40 (protein and mRNA) was measured by immunohistochemistry and in situ hybridization. Our study indicated that CD40 is constitutively expressed in human gastric carcinoma tissues. Positive expression of CD40 (protein and mRNA) in gastric cancer tissues was closely related to the tumor TNM stage and the presence of distant metastasis, with CD40 mRNA also being correlated with the presence of lymphatic metastasis. Furthermore, the expression of CD40 (protein and mRNA) is closely related to the prognosis of gastric cancer patients. The expression of CD40 protein and mRNA is positively correlated with the presence of distant (for both protein and mRNA) and lymphatic (for mRNA only) metastasis, and an increased tumor TNM stage in gastric carcinoma. Patients who express low levels of CD40 may have a better prognosis than those who have higher levels of CD40.

CXC chemokine receptor 5 expression in gastric cancer and its clinical significance

Objective To investigate the expression of CXC chemokine receptor 5(CXCR5)in human gastric cancer cell lines and gastric carcinoma tissues and its clinical significance. Methods Flow cytometry was performed to analyze the CXCR5 expression in human gastric cancer cell lines, BGC-823, SGC-7901 and HGC-27.Immunohistochemistry and tissue-microarray were used to detect the CXCR5 expression in human gastric cancer tissues and adjacent normal tissues from 90 patients. Results The flow cytometry revealed that the CXCR5 expression was detectable in BGC-823, SGC-7901 and HGC-27 cells.The results of tissue microarray and immunohistochemistry showed that the ratio of higher CXCR5 expression in gastric cancer tissues was 52. 87%.The CXCR5 expression level in patients with tumor size≤2. 8 cm group was significantly lower than that in patients with tumor size> 2. 8 cm(χ2= 3. 995,P 0. 05).Survival analysis showed that the overall survival rate of the patients with high CXCR5 expression was lower than that of the patients with low CXCR5 expression[hazard ratio(HR)= 1. 810,95% confidence interval(CI):0. 980 3-3. 341 0,P> 0. 05]. Conclusion CXCR5 is involved in the oncogenesis and progression of human gastric cancer. Key words: Gastric cancer; CXC chemokine receptor 5

Expression of erythropoietin producing human hepatocellular receptor A2 and CD133 in gastric carcinoma and their correlation with development of gastric cancer

Objective To analyze the expression of erythropoietin producing human hepatocellular receptor A2(EphA2)and CD133 in gastric carcinoma and their relationship with clinicopathological features and the prognosis of gastric carcinoma. Methods Envision immunohistochemical method was used to assess the expression of EphA2 and CD133 in 82 cases of human gastric carcinoma tissues and non-cancerous adjacent gastric tissues. Results The expression rate of EphA2 in gastric carcinoma tissues was higher than that in non-cancerous adjacent gastric tissues(86.59% vs.20.73%,P< 0.01). The expression rate of CD133 in gastric carcinoma tissues was higher than that in non-cancerous adjacent gastric tissues(67.07% vs.10.98%,P< 0.01).The expression of Eph A2 was related to TNM stage and lymph node metastasis of gastric carcinoma(P< 0.05). There was a close correlation between the expression of CD133 and histological grade, TNM stage and lymph node metastasis(P<0.05). Conclusion The overexpression of EphA2 and CD133 may play certain roles in the pathogenesis of gastric carcinoma. Key words: Gastric carcinoma; Eerythropoietin producing human hepatocellular receptor A2; CD133; Immunohistochemical method

Expression of microRNA-433 in gastric carcinoma and the clinical significance

Objective To investigate the expression of micmRNA (miR)-433 in gastric carcinoma and the clinical significance.Methods Eighty pairs of human gastric carcinoma tissue samples were obtained from patients who underwent surgical resection.The level of miR-433 in 80 caes of gastric carcinomas and the paired adjacent normal tissues was quantified by real-time fluorescent quantitative polymerase chain reaction (FQ-PCR),and the relationship between miR-433 and clinicopathological features in gastric carcinoma was analyzed.Results The expression of miR-433 in gastric carcinoma tissue (△Ct:9.73 ±2.96) was significantly decreased as compared with the paired adjacent normal tissues (△Ct:12.25 ±2.07) (P ＜ 0.05).The evaluated level of miR-433 was associated with TNM classification,tumor size,lymph node metastases and local invasion in gastric carcinoma,but not with sex,age,and differentiation.Conclusion These finding suggested miR0433 may play important roles in the development,progression,invasion and metastasis of gastric carcnima. Key words: MicmRNA-433 ; Gastric carcinoma

MiR‐494 acts as an anti‐oncogene in gastric carcinoma by targeting c‐myc

We recently showed that miR-494 was downregulated in gastric carcinoma (GC). The objectives of this study were to determine the role of miR-494 in GC malignancy and to identify its target genes. Real-time polymerase chain reaction was employed to quantify the expression level of miR-494 and c-myc in gastric cancer tissues. Bioinformatics was used to predict the downstream target genes of miR-494, which were confirmed by luciferase and RNA immunoprecipitation assays. Cell functional analyses and a xenograft mouse model were used to evaluate the role of miR-494 in malignancy. miR-494 was downregulated in human GC tissues and in GC cells and was negatively correlated with c-myc expression. High level of c-myc or low level of miR-494 correlated with poor prognosis. The miR-494-binding site in the c-myc 3' untranslated region was predicted using TargetScan and was confirmed by the luciferase assay. Additionally, c-myc and miR-494 were enriched in coimmunoprecipitates with tagged Argonaute2 proteins in cells overexpressing miR-494. Furthermore, a miR-494 mimic significantly downregulated endogenous c-myc expression, which may contribute to the delayed G1/S transition, decreased synthesis phase bromodeoxyuridine incorporation, and impaired cell growth and colony formation; on the other hand, treatment with a miR-494 inhibitor displayed the opposite effects. Reduced tumor burden and decreased cell proliferation were observed following the delivery of miR-494 into xenograft mice. miR-494 is downregulated in human GC and acts as an anti-oncogene by targeting c-myc. miR-494 plays a role in the pathogenesis of gastric cancer in a recessive fashion.

Downregulation of microRNA-155 accelerates cell growth and invasion by targeting c-myc in human gastric carcinoma cells.

MicroRNAs (miRNAs) are a recently discovered class of small non-coding RNAs that regulate gene expression. miRNAs can contribute to cancer development and progression and are differentially expressed in normal tissue and cancer. In the present study, our aim was to investigate the expression of miR-155 in gastric cancer and to explore the mechanisms by which it influences gastric cancer cells. The level of miR-155 in 52 gastric carcinoma and corresponding non-tumor tissues was quantified by real-time reverse transcriptase-polymerase chain reaction. We used the data from EdU, CASY and cell adhesion assays to show how the expression of miR-155 affects viability and proliferation in SGC-7901 cancer cells. We also performed functional assays using the 3'-untranslated region (3'-UTR) of the c-myc gene as a miR-155 target in a luciferase reporter assay system. Our results indicated that miR-155 is downregulated in both human gastric carcinoma tissues and SGC-7901 cells. The high expression level of miR-155 may significantly downregulate cancer cell viability, proliferation and attachment. The level of miR-155 could influence endogenous c-myc expression in SGC-7901 cells, and may decrease its expression by binding to 3'-UTR of c-myc. In conclusion, our results suggest that miR-155 is extensively involved in the cancer pathogenesis of gastric carcinoma and support its function as recessive cancer genes. c-myc is an important miR-155 target gene.