Expression In Human Gastric Cancer Research Articles

UBE2L3 expression in human gastric cancer and its clinical significance

PurposeGastric cancer (GC) is prevalent as one of the most common malignant tumors globally, with a particularly high incidence in China. The role of UBE2L3 in the initiation and progression of various cancers has been well documented, but its specific significance in GC is not yet fully elucidated. The objective of this study is to examine the expression and importance of UBE2L3 in human gastric cancer tissues.MethodsImmunohistochemical staining and survival analysis were conducted on 125 cases of GC. Western blot and quantitative real-time polymerase chain reaction (qRT-PCR) were employed to assess the expression of UBE2L3 in GC cell lines. Cell lines with UBE2L3 knockdown and overexpression were cultured through lentivirus transfection and subsequently assessed using Western blot analysis. The involvement of UBE2L3 in the proliferation, invasion, and apoptosis of GC cells was confirmed through in vitro experiments, and its capacity to facilitate tumor growth was also validated in in vivo studies.ResultsThe up-regulation of UBE2L3 expression was observed in GC, and its high expression was found to be significantly associated with the degree of differentiation (χ2 = 6.153, P = 0.0131), TNM stage (χ2 = 6.216, P = 0.0447), and poor overall survival. In vitro, UBE2L3 has been shown to enhance functions in GC cell lines, such as promoting proliferation and invasion, and inhibiting apoptosis. In vivo experiments have validated the role of UBE2L3 in promoting tumor growth.ConclusionsThe findings of our study demonstrate the significant involvement of UBE2L3 in the pathogenesis and advancement of gastric cancer, suggesting its potential as a therapeutic target.

IL-36G promotes cancer-cell intrinsic hallmarks in human gastric cancer cells.

Interleukin-36 gamma (IL-36G) is a member of the IL-36 subfamily of cytokines and acts as a potent driver of inflammation. IL-36G has been extensively characterized in the pathogenesis of psoriasis and has been recently described to play roles in wound healing particularly in the gastrointestinal tract. However, the effects of IL-36G during cancer development including gastric cancer remain unexplored. Here, we show that IL-36G induced ERK1/2 activation in AGS, MKN1 and MKN45 human gastric cancer cell lines. Moreover, IL-36G induced colony formation, migration and invasion of these gastric cancer cell lines that was inhibited by the natural antagonist, IL-36 receptor antagonist (RA). Interrogation of TCGA stomach adenocarcinoma patient datasets revealed highly elevated IL-36G gene expression in human gastric cancer compared to normal tissue independent of tumor stage, and high IL-36G expression corresponded with poorer patient survival. Collectively, our results indicate for the first time that IL-36G supports a neoplastic phenotype in human gastric cancer cells.

Expression of Concern: Prognostic values of inhibitory κB kinases mRNA expression in human gastric cancer.

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IL-1R2 expression in human gastric cancer and its clinical significance.

Background: Interleukin-1 receptor type II (IL-1R2), also known as CD121b, is a member of the IL-1 receptor family. IL-1R2 acts as negative regulator of the IL-1 system, modulating IL-1 availability for the signaling receptor. IL-1R2 is abnormally expressed in many human inflammatory diseases and cancers, and has important clinical significance. The present study was designed to investigate IL-1R2 expression in human gastric cancer (GC) tissues and the associated clinical implications. Methods: Immunohistochemistry was used to identify the clinical significance and prognostic value of IL-1R2 expression in GC tissues. We investigated IL-1R2 expression in GC tissues, cells, and serum using real-time PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) assays. Results: IL-1R2 was highly expressed in GC tissues, and the overall survival in patients with advanced GC and high IL-1R2 expression was significantly poorer than that in patients with advanced GC and low IL-1R2 expression. Moreover, IL-1R2 mRNA levels in GC tissues and most GC cells were higher than those in para-cancer tissues and GES1 human gastric mucosal epithelial cells. The level of plasma-soluble IL-1R2 in GC patients was higher than that of the healthy control group. Conclusion: Increased IL-1R2 levels are involved in the initiation and progression of human GC, and IL-1R2 might be employed to develop immunotherapeutic approaches targeting GC.

Clinicopathologic significance of TROP2 and phospho-TROP2 in gastric cancer.

Trophoblast cell-surface antigen 2 (TROP2) is a transmembrane glycoprotein expressed in epithelial cells. Increased TROP2 expression has been reported to be associated with malignant progression in most carcinomas; however, TROP2 has a tumor-suppressive function in certain types of cancer. Since the function of TROP2 is controversial, the present study subsequently aimed to clarify the clinicopathologic significance of TROP2 and pTROP2 expression in human gastric cancer (GC). The cases of 704 patients with GC who underwent gastrectomy were retrospectively analyzed. The expression levels of TROP2 and pTROP2 in each tumor were evaluated by immunohistochemistry. The association between the clinicopathologic features of patients with GC and the levels of TROP2 and pTROP2 in their tumors was analyzed. Increased TROP2 and pTROP2 expression was identified in 330 (46.9%) and 306 (43.5%) of the 704 patients with GC, respectively. Increased TROP2 expression was associated with the histological intestinal type, high tumor invasion depth (T3/T4), lymph node metastasis, lymphatic invasion and venous invasion. By contrast, increased pTROP2 expression was associated with intestinal type, low tumor invasion depth (T1/2), no lymph node metastasis and no lymphatic invasion. Increased TROP2 expression was associated with poorer overall survival (OS) (P<0.01; log rank test), whereas increased pTROP2 expression was significantly associated with improved OS (P<0.01; log rank test). In conclusion, increased expression levels of TROP2, but not pTROP2, may be associated with the metastatic ability of GC, resulting in poor prognosis of patients with GC.

Prognostic value of small mother against decapentaplegic expression in human gastric cancer

Gastric cancer is the fifth most common malignancy in the world with alow 5-year survival rate. To date, no study has investigated the prognostic role of the small mother against decapentaplegic (SMAD) in gastric cancer. The association of SMADs with overall survival (OS) of gastric cancer was analyzed on the online Kaplan-Meier (KM) plotter database. Clinical data such as stage, differentiation, gender, treatment, and Her2 mutation status of gastric cancer patients were analyzed. The (E)-SIS3 was used to inhibit SMAD3 expression in gastric cancer cells, and the effects of SMAD3 on gastric cancer cells were analyzed via real-time cellular analysis (RTCA), flow cytometry, colony formation, and immunofluorescence assay. The results showed that the high expression of three members of SMADs (SMAD1, SMAD2, SMAD4) was correlated with afavorable OS of gastric cancer patients. Meanwhile, SMAD3 expression level indicated highly differentiated cancer. We also observed that surgical treatment was associated with high expression level of SMAD1 and SMAD2. Besides, the effect of Her2 on gastric cancer was not noticeable. Moreover, (E)-SIS3 pharmacological assay revealed that inhibition of expression of SMAD3 suppressed the proliferation and migration ability of gastric cancer cells via inducing apoptosis. Collectively, these results demonstrate that the high expression level of three members of SMADs (SMAD1, SMAD2, and SMAD4) is significantly correlated with favorable OS of gastric cancer patients, which is opposite to SMAD3. Thus, SMADs regulate the differentiation of cancer and can be used to guide treatment decisions.

The LPS-Treated Human Gastric Cancer Cells (AGS) Show a Significant Higher Tendency to Proliferation, Inflammation and Cannabinoid Receptor 1 Expression

Background: Cannabinoid receptor 1 (CB1R) that located throughout the central, peripheral, and enteric nervous system can be found all over the gastrointestinal tract. Cannabinoid receptors (CBRs) play important roles in pathophysiological processes and have been identified as a therapeutic target for developing novel anticancer agents. Objectives: The purposes of this study were to evaluate the CB1R expression in human gastric cancer, mRNA and protein expression of CB1R under lipopolysaccharide (LPS)-mediated inflammation condition in human gastric cancer cells (AGS), and the effects of inflammation on cell proliferation in LPS-stimulated AGS cells. Methods: CB1R mRNA expression in human gastric cancer samples and AGS cells were assessed by quantitative real-time polymerase chain reaction (qRT-PCR). The expression level of CB1R, after inflammation induction using LPS, was evaluated by qRT-PCR and western blot techniques. Cell proliferation was evaluated using 5-bromo-2-deoxyuridine (BrdU) labeling assay. Results: CB1R mRNA was significantly higher in human gastric cancer samples compared to adjacent normal tissues. LPS induced CB1R mRNA and protein expression in stimulated cells and promoted the proliferation of AGS cells. Conclusions: Our results show the increased expression of CB1R in gastric cancer samples and reveal that LPS induction increases the expression of CB1R and promotes cell proliferation in AGS cells. Accordingly, CB1R may be suggested as a potential molecular target for diagnostic and therapeutic aims in patients with gastric cancer.

Lentivirus-Mediated VEGF Knockdown Suppresses Gastric Cancer Cell Proliferation and Tumor Growth in vitro and in vivo.

PurposeGastric cancer has a high mortality rate worldwide. Although treatments, such as molecular-targeted therapy, have been introduced, the resulting long-term survival and prognosis remain unsatisfactory. Downregulation of the target genes using lentivirus-mediated short hairpin RNA (shRNA) can be an effective therapeutic strategy for patients with gastric cancer. Overexpressed vascular endothelial growth factor A (VEGF) in human gastric cancer cells can be an effective novel therapeutic target for human gastric cancer. Thus, this study aimed to evaluate the therapeutic effects of lentivirus-mediated knockdown of VEGF gene expression in human gastric cancer growth.Materials and MethodsSpecific shRNA sequences targeting VEGF were designed to construct a lentiviral expression vector. After human gastric carcinoma cells (cell line NCI-N87) were infected with the lentiviral vector, the therapeutic effects of the lentivirus-mediated shRNA targeting VEGF were analyzed both in vitro and in vivo.ResultsStable suppression of VEGF gene expression in NCI-N87 cells using shRNA (ShVEGF) showed significant inhibition of cell proliferation, clonogenicity, and cell motility. ShVEGF also showed increased G0/G1 cell cycle arrest and apoptosis. In addition, in vivo results from nude mice xenografted ShVEGF showed significant inhibition of tumor growth. Assessing the therapeutic effects of intratumoral injection of lentivirus-targeting VEGF (Virus_VEGF) revealed that it significantly inhibited tumor growth compared to that in the Virus_Scramble or saline injection control groups.ConclusionThe constructed ShVEGF showed significant inhibition of NCI-N87 gastric cancer cell growth both in vitro and in vivo. These experimental results suggest a novel therapeutic strategy for patients with gastric cancer using lentivirus-mediated shRNA targeting VEGF.

Abstract 989: The relationship between TP53 gene status and carboxylesterase 2 expression in human gastric cancer

Abstract Carboxylesterases are serine hydrolases that are involved in the metabolisms of various endogenous and exogenous compounds. They are also required for activation of many anti-cancer prodrugs. For example, irinotecan (CPT-11), an anti-cancer prodrug that has been approved for the treatment of many types of solid tumors including gastric cancer, is converted by the carboxylesterase CES2 to its active metabolite 7-ethyl-10-hydroxycamptothesin (SN-38), a very potent topoisomerase I inhibitor. Among carboxylesterase isozymes, CES2 is most highly expressed in the gastrointestinal tract. Thus, the expression of CES2 may play an important role in local (i.e., intratumoral) activation of anti-cancer prodrugs such as irinotecan in the gut. Recent studies with cultured cancer cell lines have shown that CES2 expression is regulated by the tumor suppressor protein p53. However, whether CES2 expression is affected by the presence of p53 mutation in clinical cancer samples still remains unclear. In this study, we focused on the regulatory mechanism of CES2 expression in gastric cancer. First, we examined the relationship between TP53 gene status and CES2 expression using gastric cancer cell lines. Several gastric cancer cell lines expressing wild-type p53 (AGS, NUGC4, MKN74, and HSC58) were treated with nutlin-3a, a drug that inhibits the interaction between p53 and the E3 ubiquitin ligase MDM2 and thereby directly activates p53 signaling without genotoxic side effects. The expression of p21, a downstream target of p53, was increased following nutlin-3a treatment in two p53 wild-type cell lines NUGC4 and HSC58. The expression of CES2 was also upregulated by nutlin-3a in three p53 wild-type cell lines AGS, NUGC4, and HSC58. As expected, the expression levels of p21 and CES2 were not largely affected by nutlin-3a in gastric cancer cell lines with TP53 mutations. These results indicate that CES2 expression is positively regulated by the p53 pathway in most gastric cancer cells. We also investigated the relationship between TP53 gene status and CES2 expression in human gastric cancer samples. Our results may provide useful information for predicting the efficacy of anti-cancer prodrugs that are activated by CES2 in gastric cancer. Note: This abstract was not presented at the meeting. Citation Format: Yoshinori Kohira, Hyeon-Cheol Lee, Momoko Ishimine, Hajime Orita, Toshiyuki Kobayashi, Koichi Sato, Takehiko Yokomizo, Tetsu Fukunaga. The relationship between TP53 gene status and carboxylesterase 2 expression in human gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 989.

ANXA2 Silencing Inhibits Proliferation, Invasion, and Migration in Gastric Cancer Cells.

Annexin A2 (ANXA2) has been well known to associate with the progress of malignant tumor. However, the biological behavior of ANXA2 in gastric cancer (GC) remains unclear. We made a hypothesis in transcriptome level from TCGA datasets. Then, we used immunohistochemical staining to quantify the expression level of ANXA2 protein in GC tissues compared with adjacent tissues. Quantitative real-time PCR and western blot were used for analyzing ANXA2 expression in human GC (SGC-7901, MKN-45, BGC-823, and AGS) cell lines. We investigated the effect of a lentivirus-mediated knock-down of ANXA2 on the proliferation, invasion and migration of gastric cancer AGS cells. Cell proliferation was examined by MTT and colony formation tests. Cell apoptosis and cycle were measured by flow cytometry. Migration and invasion were detected by transwell assay. We found that high expression of ANXA2 can increase the mobility of cancer cells from TCGA datasets. ANXA2 was upregulated in GC tissues compared with adjacent tissues. AGS cell line displayed significantly higher expression of ANXA2 among the four GC cell lines. In addition, ANXA2 silencing led to a weakened ability of proliferation, invasion, and migration in GC cells; targeting of ANXA2 may be a potential therapeutic strategy for GC patients.

Prognostic values of inhibitory κB kinases mRNA expression in human gastric cancer.

Background: Inhibitory κB kinases (IKKs) play a key role in modulating proinflammatory and growth stimulating signals through their regulation of the nuclear factor κB (NF-κB) cascade. Therefore, the level of expression of IKKs represents a viable prognostic predictor with regard to various pathological processes. The prognostic value of IKKs expression in gastric cancer remains unclear. Methods: We used the ‘Kaplan–Meier plotter’ (KM plotter) online database, to explore the predictive prognostic value of individual IKKs members’ mRNA expression to overall survival (OS) in different clinical data including pathological staging, histology, and therapies employed. Results: Our results revealed that a higher mRNA expression of inhibitor of NF-κB kinase subunit α (IKKα) was correlated to better OS, whereas higher mRNA expression of IKKβ, inhibitor of NF-κB kinase subunit γ (IKKγ), inhibitor of NF-κB kinase subunit ε (IKKε), and suppressor of IKKε (SIKE) were generally correlated to unfavorable OS in gastric cancer. Increased mRNA expression of IKKε also showed better outcomes in stage IV gastric cancer. Further a correlation between elevated levels of mRNA expression of both IKKε and SIKE was found to have favorable OS in diffuse type gastric cancer. It was also revealed that high expression of SIKE had favorable OS when treated with other adjuvant therapies, while worse OS when treated only with 5FU therapy. Conclusion: Our results suggest that mRNA expression of individual IKKs and SIKE are associated with unique prognostic significance and may act as valuable prognostic biomarkers and potential targets for future therapeutic interventions in gastric cancer.

Clinical significance of retinoic acid-induced protein I expression in human gastric cancer

Objective To investigate the clinical significance and regulation of retinoic acid-induced protein I (RIG-I) in human gastric cancer. Methods Immunohistochemistry was used to study RIG-I expression in gastric cancer and normal tissues. We used Wilcoxon test to analyze the difference of RIG-I expression levels in cancer and normal tissues. Chi-square and Log-rank tests were used to analyze the RIG-I expression in cancer tissues in relation to patients’ clinical parameters and prognoses respectively. The gastric cancer cell lines SGC-7901 and AGS were used to construct the stable knockdown expression of RIG-I using RNA interference (RNAi) method. The cell counting kit-8 (CCK-8), wound healing, and Transwell assays were used to examine the cellular function after RIG-I knockdown of these cells. Results RIG-I expression level in human gastric cancer tissues was significantly lower than that in adjacent normal tissues (U=1 490, P=0.001). The ratio of higher RIG-I expression in cancer patients with pathological stage (Ⅲ-Ⅳ) was significantly lower than that in normal tissues (χ2=4.668, P=0.031). The overall survival of the patients with higher RIG-I expression was significantly longer than that with lower RIG-I expression (P=0.023). The COX model showed that the age (P=0.047), TNM stage (P=0.039) and the RIG-I expression (P=0.007) could be used as independent prognostic predictors for cancer patients. CCK-8 assay showed that at the time points of 48 h and 72 h after culture, the A450 value in LV-RIG-I-short hairpin RNA (shRNA) group was significantly higher than that in LV-NC group (for SGC7901: P=0.000 and P=0.000 respectively; for AGS: P=0.002 and P=0.016 respectively). The wound healing assay showed that the cell migration abilities in LV-RIG-I-shRNA group was significantly stronger than LV-NC group (for SGC7901: P=0.001; for AGS: P=0.004). The Transwell assay showed that the cell invasion abilities in LV-RIG-I-shRNA group was significantly stronger than that in LV-NC group (for SGC7901: P=0.032; for AGS: P=0.016). Conclusion RIG-I plays important roles in gastric cancer progression, its knockdown could promote proliferation, migration and invasion of cancer cells, and thus could be used as potential therapeutic target for gastric cancer. Key words: Retinoic acid-induced protein I; Gastric cancer; RNA interference; Immunohistochemistry

Significant association of DIRC1 overexpression with tumor progression and poor prognosis in gastric cancer.

DIRC1, Disrupted in Renal Cancer 1, was identified as a breakpoint-spanning gene in a chromosomal translocation, which was associated with the onset and progression of some cancers. However, the expression in human gastric cancer (GC) and the role of DIRC1 in human gastric tumorigenesis are unknown. Thereby, the main purpose of this study was to unearth the association of DIRC1 with GC. By analyzing The Cancer Genome Atlas (TCGA) datasets, the expression of DIRC1 in GC and normal gastric tissues were compared. Besides, its association with clinicopathological significance, overall survival (OS) and independent prognosis were analyzed by Pearson's x2 test, Kaplan-Meier method and Cox proportional hazards model, respectively. Functionally, the knockdown of DIRC1 was performed by siRNA method; moreover, its effects on the proliferation and metastasis of GC cells were examined by CCK-8 and transwell assays. Furthermore, the key markers of protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling were tested by Western blot assay. The results showed that high expression of DIRC1 was found in GC tissues compared with normal gastric tissues. High expression of DIRC1 was associated with more cases of severer tumor malignancy and shorter OS; besides, high-level of DIRC1 was suggested to be an independent prognostic factor for GC. Furthermore, the knockdown of DIRC1 inhibited SGC-7901 GC cells proliferation, migration and invasion. Mechanically, the activity of AKT/mTOR signaling was suppressed by the knockdown of DIRC1. These findings offer clinical associations and an in vitro evidence showing that the knockdown of DIRC1 impeded the GC carcinogenicity possibly via suppression of AKT/mTOR signaling. This work might provide a potential therapeutic target for GC treatment.

CagA increases DNA methylation and decreases PTEN expression in human gastric cancer.

Gastric cancer is one of the leading causes of cancer-associated mortality worldwide. Cytotoxin-associated gene A (CagA) has been reported to be associated with gastric diseases. Phosphatase and tensin homolog (PTEN) and tet methylcytosine dioxygenase 1 (Tet1) are important tumor-suppressor genes. The present study aimed to investigate the underlying functions of CagA in human gastric cancer, and to explore the associations between CagA, PTEN and Tet1 in gastric cancer. For that purpose, CagA overexpression and Tet1 interference recombinant lentiviral plasmids were constructed. Quantitative polymerase chain reaction (qPCR) was utilized to screen gene expression in HGC-27 human gastric cancer cells overexpressing CagA. qPCR and western blotting were used to detect gene and protein expression, respectively. In addition, the methylation status of PTEN was detected by methylation-specific PCR. The expression levels of PTEN, Tet1, apolipoprotein B mRNA editing enzyme catalytic subunit (APOBEC)3A, APOBEC3C and APOBEC3F were significantly decreased in the CagA overexpression group compared with in the negative control group in HGC-27 cells. Compared with in the negative control group, the mRNA and protein expression levels of PTEN were markedly decreased in cells with Tet1 interference. The decreased expression of PTEN was associated with increased methylation levels in the cells. In addition, the protein expression levels of PTEN were significantly decreased in HGC-27 cells when CagA was overexpressed. The expression levels of PTEN and Tet1 were also markedly decreased in CagA+ gastric cancer tissues compared with in non-cancerous tissues. The decreased expression of PTEN in CagA+ gastric cancer tissues was associated with increased methylation levels. In conclusion, overexpression of CagA significantly decreased the expression of PTEN, Tet1, APOBEC3A, APOBEC3C and APOBEC3F in human gastric cancer. In addition, CagA increased DNA methylation and decreased PTEN expression, which was reversed by Tet1 overexpression. The present study may facilitate future therapeutic approaches targeting human gastric cancer.

NLRP6, decreased in gastric cancer, suppresses tumorigenicity of gastric cancer cells.

BackgroundHelicobacter pylori (H. pylori) infection has been regarded as a main risk factor for gastric cancer. Nod-like receptor pyrin domain-containing protein 6 (NLRP6), a component of inflammasome, has been linked to colorectal tumorigenesis. Here, we aimed to evaluate NLRP6 expression profile and functions in gastric cancer.Materials and methodsWe examined NLRP6 expression in gastric cancer and adjacent normal gastric tissues. The biological functions and mechanism of NLRP6 overexpression in gastric cancer cells were investigated.ResultsDownregulated NLRP6 expression in human gastric cancer significantly correlated with H. pylori infection, tumor size, TNM stage, lymph node metastasis, and overall survival. NLRP6 overexpression in gastric cancer cells led to a significant decrease in cell proliferation, migration, and invasion, as well as a notable increase in cell apoptosis, whereas NLRP6 knockdown had opposing effects. In addition, NLRP6 overexpression significantly repressed STAT3 phosphorylation and the transcription of its target genes, Bcl-2 and MMP-2. Moreover, forkhead box O3 (FOXO3), a transcription factor regulated by H. pylori, was demonstrated as an upstream regulator of NLRP6 transcription.ConclusionOur study may provide insight into the understanding of NLRP6 as a tumor suppressor and implicate the potential application of NLRP6 for gastric cancer treatment.

Hypermethylation of miR-338-3p and Impact of its Suppression on Cell Metastasis Through N-Cadherin Accumulation at the Cell -Cell Junction and Degradation of MMP in Gastric Cancer

Background/Aims: MicroRNAs (miRNAs) have been well studied in human carcinogenesis and cancer progression. Our previous study showed the down-regulation of miR-338-3p expression in human gastric cancer (GC). However, the reasons of this dysregulation remain largely unclear. Methods: Bisulfite sequence analysis was performed to explore the methylation status of the promoter region of miR-338-3p. Cell wound-healing and transwell assays were performed to examine the capacity of cell migration and cell interaction. A dual-luciferase reporter was used to validate the bioinformatics-predicted target gene of miR-338-3p. Western blotting, RNA interference, and immunofluorescence (IF) were used to evaluate the expression of MMPs and the location of N-cadherin to determine the mechanism underlying miR-338-3p-induced anti-tumor effects. Results: miR-338-3p was epigenetically silenced, and this loss of expression was significantly correlated with the Borrmann Stage in GC. Restoring miR-338-3p expression in BGC-823 cells inhibited cell migration and invasion. Moreover, Ras-related protein (Rab-14) and Hedgehog acyltransferase (Hhat) were identified as direct targets of miR-338-3p. Both enforced expression of miR-338-3p and small interfering RNA induced Rab14-mediated accumulation of N-cadherin in the cell -cell junctions or Hhat-associated matrix metalloproteinase (MMP) degradation, which may underline the metastasis defects caused by loss of miR-338-3p in GC. Conclusion: These data indicate that miR-338-3p functions as a tumor suppressor in GC, and that the hypermethylation status of its CpG island might be a novel potential strategy for treating GC.

SUMO1 Pseudogene 3 (SUMO1P3) Expression in Human Gastric Cancer and Its Clinical Significance

Introduction/Aim: The aim of this study was to investigate SUMO (small ubiquitin-like modifier) 1 pseudogene 3, SUMO1P3 expression, as one of the pseudogene-expressed long non-coding RNA (lncRNAs) in gastric cancer (GC) patients. Materials and Methods: Fresh gastric cancer and adjacent non-tumor tissues were collected from 182 GC patients, who were admitted to the Alzahra Hospital, Isfahan, Iran on December 2014 to January 2016. Quantitative reverse transcription-polymerase chain reaction was used to investigate the SUMO1P3 levels. Then, the association between the level of SUMO1P3 in gastric cancer tissues and the clinicopathological features of patients with gastric cancer was analyzed. To find the differences of SUMO1P3 levels between gastric cancer tissues and adjacent non-tumor tissues, one-way analysis of variance (ANOVA) was applied. A significance level of 0.05 was considered for the tests. Results: The results showed that SUMO1P3 levels in males were not significantly higher than those in females (p = 0.485). No significant difference of SUMO1P3 expression was observed between patients under 64 years old and above (p = 0.155). The SUMO1P3 levels were not associated with perineural invasion (p = 0.319), lymphatic invasion (p = 0.797), invasion depth (p = 0.790), location of the tumor (p = 0.811), tumor size (p = 0.635), and grading (p = 0.289). Conclusions: These results indicated that in our patient population and according to the used method in this study, pseudogene-expressed lncRNA SUMO1P3 may not be a potential biomarker in the diagnosis of gastric cancer.

Abstract 4146: Overexpression of C5a receptor becomes risk factor in gastric cancer

Abstract Background: C5a is one of the important factors produced on complement pathway and a strong chemokine. There is emerging evidence that C5a is generated in the cancer microenvironment and C5a receptor (C5aR) is expressed in various cancer cells and associated with invasive ability in several cancer cells. However, the role of C5aR in gastric cancer (GC) is still mostly unknown. Aim: To investigate the clinical significance of C5aR expression in human GC. Method: 168 patients underwent gastrectomy after the diagnosis of gastric cancer from January 1st 2001 to December 31th 2009. C5aR-expression of GC cells was investigated in all 168 patients and was analyzed in regard to an association with clinicopathological factors and outcomes in the patients. Additionally, in vitro experiments were used to examine the proliferation and invasion of GC cells by using the GC cell lines that had high-expression of C5aR. Result: High-expression of C5aR was found in 55 patients (32.7%). High-expression of C5aR was significantly related to depth of invasion, stage, lymphatic and vascular invasion. Among the 146 patients with a tumor stage lower than stageIV, the 5-years recurrence-free and overall survival rates of patients in the high-expression of C5aR group were significantly lower than those in the low-expression of C5aR group (91.0% vs 52.4%, p = 0.007 and 87.2% vs 59.1%, p = 0.003, respectively). The high-expression of C5aR group had more frequently distant metastasis than the low-expression of C5aR group during the follow-up time, presenting itself mainly in liver metastasis and peritoneal dissemination (p = 0.020 and p = 0.026). We found that the gastric cancer cell lines MKN1 and MKN7 had the high-expression of C5aR with western blotting in vitro. Moreover, matrigel chamber assay revealed that 10 nM of recombinant C5a enhances cell invasiveness of MKN1 by 2.55-fold and the cell invasiveness of MKN7 by 2.90-fold, but such an enhancement by C5a was not observed in control cells. Conclusions: The gastric cancer patients with a high expression of C5aR were associated with poor prognosis, and the invasive ability of gastric cancer cell lines highly expressing of C5aR were promoted by C5a. Thus, targeting this C5a-C5aR axis might provide a useful therapeutic option for gastric cancer treatment. Citation Format: Takayoshi Kaida, Hidetoshi Nitta, Kota Arima, Hideaki Takeyama, Takaaki Higashi, Katunobu Taki, Hiromitsu Hayashi, Daisuke Hashimoto, Akira Chikamoto, Takatoshi Ishiko, Toru Beppu, Hideo Baba. Overexpression of C5a receptor becomes risk factor in gastric cancer. [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 4146. doi:10.1158/1538-7445.AM2015-4146

Significances of contactin-1 expression in human gastric cancer and knockdown of contactin-1 expression inhibits invasion and metastasis of MKN45 gastric cancer cells.

Purpose Contactin-1 (CNTN-1) has been shown to promote cancer metastasis. Previously, we have reported that the expression of CNTN-1 was upregulated in gastric cancer tissues compared with adjacent normal tissues. Here, we investigated the significance of CNTN-1 expression and its underlying mechanism of metastasis mediated by epithelial–mesenchymal transition (EMT) in gastric cancer.MethodsThe expressions of CNTN-1 and EMT-related proteins were assayed through immunohistochemical staining of pathological specimens from patients with gastric cancer. Other methods including reverse transcriptase polymerase chain reaction, Western blotting, stably transfected against CNTN-1 into MKN45 cells, migration and invasion assays in vitro and nude mouse tumorigenicity in vivo were also utilized.ResultsThe results revealed that CNTN-1 expression was elevated and positively correlated with metastasis, EMT-related markers and poor prognosis in patients with gastric cancer. Moreover, CNTN-1 expression might associate with invasive ability to some extent in gastric cancer cell lines KATO-Ш, SGC7901 and MKN45. Knockdown of CNTN-1 expression in MKN45 cells using short hairpin RNA (shRNA) had notable effects on cell migration and invasion, rather than proliferation in vitro and in vivo. Furthermore, suppression of CNTN-1 expression altered EMT through inhibition of transcription factor Slug, rather than Snail.ConclusionOur study demonstrated that the elevated CNTN-1 expression closely correlated with cancer metastasis and patient survival, and its functions seemed to be important in migration and invasion of gastric cancer cells via EMT alteration probably mediated by inhibition of Slug. CNTN-1 may be a potential therapeutic target for gastric cancer.

Clinicopathological correlation of keratinocyte growth factor and matrix metalloproteinase-9 expression in human gastric cancer.

Keratinocyte growth factor (KGF) is reported to be implicated in the growth of some cancer cells. Matrix metalloproteinase 9 (MMP-9) is thought to enhance the tumor invasion and metastasis ability. This study was aimed at analyzing the relationship between KGF and MMP-9 expression and patients' clinicopathological characteristics to clarify the clinical significance of the expression of KGF and MMP-9 in gastric cancer. Tissue samples from 161 patients with primary gastric cancer were investigated using immunohistochemistry. The relationship between KGF and/or MMP-9 expression and clinicopathological characteristics was analyzed. KGF expression and MMP-9 expression in gastric cancer tissue were observed in 62 cases (38.5%) and 97 cases (60.2%), respectively. MMP-9 was significantly associated with depth of invasion, lymph node metastasis and TNM stage. The prognosis of MMP-9-positive patients was significantly poorer than that of MMP-9-negative patients (p = 0.009). KGF expression was positively correlated with MMP-9 expression in gastric cancer, and the prognosis of patients with both KGF- and MMP-9-positive tumors was significantly worse than that of patients with negative tumors for either factor (p = 0.045). Expression of MMP-9 was revealed to be an independent prognostic factor (p = 0.026). Coexpression of KGF and MMP-9 in gastric cancer could be a useful prognostic factor, and MMP-9 might also serve as a novel target for both prognostic prediction and therapeutics.