Tumorigenesis Of Gastric Carcinoma Research Articles

Plasma metabolomics combined with mass spectrometry imaging reveals crosstalk between tumor and plasma in gastric cancer genesis and metastasis

Gastric Carcinoma (GC) is a highly fatal malignant tumor with a poor prognosis. Its elevated mortality rates are primarily due to its proclivity for late-stage metastasis. Exploring the metabolic interactions between tumor microenvironment and the systemic bloodstream could help to clearly understand the mechanisms and identify precise biomarkers of tumor growth, proliferation, and metastasis. In this study, an integrative approach that combines plasma metabolomics with mass spectrometry imaging of tumor tissue was developed to investigate the global metabolic landscape of GC tumorigenesis and metastasis. The results showed that the oxidized glutathione to glutathione ratio (GSSH/GSH) became increased in non-distal metastatic GC (M0), which means an accumulation of oxidative stress in tumor tissues. Furthermore, it was found that the peroxidation of polyunsaturated fatty acids, such as 9,10-EpOMe, 9-HOTrE, etc., were accelerated in both plasma and tumor tissues of distal metastatic GC (M1). These changes were further confirmed the potential effect of CYP2E1 and GGT1 in metastatic potential of GC by mass spectrometry imaging (MSI) and immunohistochemistry (IHC). Collectively, our findings reveal the integrated multidimensional metabolomics approach is a clinical useful method to unravel the blood-tumor metabolic crosstalk, illuminate reprogrammed metabolic networks, and provide reliable circulating biomarkers.

N6-methylation in the development, diagnosis, and treatment of gastric cancer.

Gastric cancer (GC) ranks third among cancers in terms of mortality rate worldwide. A clear understanding of the mechanisms underlying the genesis and progression of GC will contribute to clinical decision making. N6-methyladenosine (m6A) is the most abundant among diverse mRNA modification types and regulates multiple facets of RNA metabolism. In recent years, emerging studies have shown that m6A modifications are involved in gastric carcinoma tumorigenesis and progression and can potentially be valuable new prospects for diagnosis and prognosis. This article reviews the recent progress regarding m6A in GC.

Hsa_circ_0014606 Derived from Exosomes Promotes Gastric Carcinoma Tumorigenesis and Proliferation by Sponging miR-514b-3p to Upregulate HNRNPC.

Gastric cancer is a common malignant tumor, and due to its insidious onset and limited screening methods, most patients are diagnosed with advanced disease and have a poor prognosis. The circRNA in exosomes has an essential role in cancer diagnosis and treatment. However, the part of hsa_circ_0014606 within exosomes in gastric cancer progression is unclear. Firstly, we extracted exosomes from the serum of gastric cancer patients and healthy individuals by ultracentrifugation and analyzed the expression of hsa_circ_0014606 in both exosomes; then knocked down hsa_circ_0014606 in vivo and in vitro, respectively, to observe its effect on the physiological function of gastric cancer cells; finally, we used bioinformatics to screen hsa_circ_0014606 targeting miRNAs and mRNAs, and experiments were performed to verify the interrelationship between the three. The results showed that the level of hsa_circ_0014606 in the serum exosomes of gastric cancer patients was significantly higher than that of the healthy population. The knockdown of hsa_circ_0014606 slowed the proliferation of gastric cancer cells, significantly reduced migration and invasion ability, accelerated apoptosis, and reduced tumor size in mice. In addition, the expression of hsa_circ_0014606 was negatively correlated with the expression of miR-514b-3p and positively correlated with the expression of heterogeneous nuclear ribonucleoprotein C (HNRNPC). In conclusion, hsa_circ_0014606 exerted a pro-cancer effect indirectly through miR-514b-3p targeting gene HNRNPC, and this study provides a new potential target for treating gastric cancer.

Vimentin binds to a novel tumor suppressor protein, GSPT1-238aa, encoded by circGSPT1 with a selective encoding priority to halt autophagy in gastric carcinoma

Circular RNAs (circRNAs) are covalently closed, endogenous molecules that are widespread in eukaryotes. Recent evidence indicates that circRNAs play important roles in carcinogenesis. Several circRNAs have been reported to comprise translatable RNA; however, whether circRNAs encode functional proteins remains unknown. In our study, circRNA sequencing was carried out using five pathologically diagnosed gastric carcinoma (GC) samples and their paired adjacent normal tissues, we characterized the circRNA GSPT1 (circGSPT1), which is expressed at low levels in GC. Antibody detections, and mass spectrometry were used to validate active circRNA translation. The spanning junction open reading frame in circGSPT1, driven by an internal ribosome entry site (IRES), encodes a functional peptide, termed GSPT1-238aa. Interestingly, GSPT1-238aa tends to select the start codon used to initiate translation. This is the first finding of selective translation driven by IRES. CircGSPT1 and GSPT1-238aa halted the proliferation, migration, and invasion in GC cells in vitro. We also confirmed that the vimentin/Beclin1/14-3-3 complex interacts with GSPT1-238aa and modulates autophagy via the PI3K/AKT/mTOR signaling pathway in GC cells. Our study reveals that GSPT1-238aa, a novel protein encoded by circGSPT1, halts GC tumorigenesis. We also provide insights into the function and underlying molecular mechanisms of GSPT1-238aa in GC and suggest that this protein represents a novel target for GC treatment.

Aberrant expression of SFRP1, SFRP3, DVL2 and DVL3 Wnt signaling pathway components in diffuse gastric carcinoma.

Diffuse gastric carcinoma (DGC) is characterized by poorly cohesive cells, highly invasive growth patterns, poor prognosis and resistance to the majority of available systemic therapeutic strategies. It has been previously reported that the Wnt/β-catenin signaling pathway serves a prominent role in the tumorigenesis of gastric carcinoma. However, the mechanism underlying the dysregulation of this pathway in DGC has not been fully elucidated. Therefore, the present study aimed to investigate the expression profiles of Wnt antagonists, secreted frizzled-related protein 1 (SFRP1) and secreted frizzled-related protein 3 (SFRP3), and dishevelled protein family members, dishevelled segment polarity protein 2 (DVL2) and dishevelled segment polarity protein 3 (DVL3), in DGC tissues. The association between the expression levels of these factors and the clinicopathological parameters of the patients was determined. Protein and mRNA expression levels in 62 DGC tumor tissues and 62 normal gastric mucosal tissues obtained from patients with non-malignant disease were measured using immunohistochemical and reverse transcription-quantitative PCR (RT-qPCR) analysis. Significantly lower protein expression levels of SFRP1 (P<0.001) and SFRP3 (P<0.001), but significantly higher protein expression levels of DVL2 (P<0.001) and DVL3 (P<0.001) were observed in DGC tissues compared with in control tissues by immunohistochemistry. In addition, significantly lower expression levels of SFRP1 (P<0.05) and higher expression levels of DVL3 (P<0.05) were found in in DGC tissues compared with those in normal gastric mucosal tissues using RT-qPCR. According to correlation analysis between the SFRP1, SFRP3, DVL2 and DVL3 protein expression levels and the clinicopathological characteristics of patients with DGC, a statistically significant correlation was found between the SFRP3 volume density and T stage (r=0.304; P=0.017) and between the SFRP3 volume density and clinical stage (r=0.336; P=0.008). In conclusion, the findings of the present study suggested that the Wnt signaling pathway components SFRP1, SFRP3, DVL2 and DVL3 may be aberrantly expressed in DGC tissues, implicating their possible role in the development of this malignant disease. The present data also revealed a positive relationship between SFRP3 protein expression and the clinical and T stage of DGC.

Exosomal circ_0088300 Derived From Cancer-Associated Fibroblasts Acts as a miR-1305 Sponge and Promotes Gastric Carcinoma Cell Tumorigenesis.

Cancer-associated fibroblast (CAF)-derived exosomes play a major role in gastric carcinoma (GC) tumorigenesis. However, the mechanism behind the activity of circular RNAs in CAF-derived exosomes in GC remains unclear. In the present study, we identified differentially expressed circ_0088300 in GC tissues and plasma exosomes. We found that CAFs delivered functional circ_0088300 to GC tumor cells via exosomes and promoted the proliferation, migration and invasion abilities of GC cells. Furthermore, we demonstrated that circ_0088300 packaging into exosomes was driven by KHDRBS3. In addition, we verified that circ_0088300 served as a sponge that directly targeted miR-1305 and promoted GC cell proliferation, migration and invasion. Finally, the JAK/STAT signaling pathway was found to be involved in the circ_0088300/miR-1305 axis, which accelerates GC tumorigenesis. In conclusion, our results indicated a previously unknown regulatory pathway in which exosomal circ_0088300 derived from CAFs acts as a sponge of miR-1305 and promotes GC cell proliferation, migration and invasion; these data identify a potential biomarker and novel therapeutic target for GC in the future.

Circular RNA MTO1 suppresses tumorigenesis of gastric carcinoma by sponging miR‐3200-5p and targeting PEBP1

Gastric carcinoma (GC) is one of the most common cancers with the fifth highest incidence of malignant tumors and the second highest death rate in the world. Ever-increasing investigations have shown that circular RNAs (circRNAs) are involved in the development of numerous cancers. But so far, the recognization for circMTO1 that is realized and studied as a cancer-suppressing gene is a small part and the regulatory mechanism of circMTO1 in GC has yet to be further explored. In this study, our experimental results delineated that circMTO1 exhibited much lower expression level in GC tissues and cells. CircMTO1 overexpression slowed down GC progression via inhibiting cell proliferation, migration, invasion and epithelial‐mesenchymal transition (EMT) process. Besides, circMTO1 acted as a sponge for miR‐3200-5p as well as it could negatively regulate the expression of miR‐3200-5p. Moreover, circMTO1 was verified to compete with PEBP1 to bind to miR‐3200-5p, thus decelerating the development of GC. In a word, this study was the first to indagate the underlying mechanism of circMTO1 in GC and confirmed circMTO1 exerted its anti-cancer effects by miR‐3200-5p/PEBP1 axis, implying that circMTO1 may become a new promising therapeutic target for GC patients.

Epstein-Barr virus miR-BART1-3p suppresses apoptosis and promotes migration of gastric carcinoma cells by targeting DAB2.

Although Epstein-Barr virus (EBV) is known to encode over 40 different miRNAs of its own, the roles of most EBV miRNAs remain unknown. Disabled homolog 2 (DAB2) is a putative tumor suppressor, but its role in gastric carcinoma (GC), especially in EBV-associated GC, needs to be clarified. Our qRT-PCR and mRNA microarray results showed that DAB2 expression was down-regulated in EBV-positive GC cells compared to EBV-negative cells. Four BART miRNAs that might target DAB2 were predicted, and we found, using a luciferase reporter assay, that miR-BART1-3p directly targeted the 3'-UTR of DAB2. The miR-BART1-3p transfection decreased DAB2 expression at both mRNA and protein levels, while transfection of an inhibitor of miR-BART1-3p, miR-BART1-3p(i), increased DAB2 expression. In addition, miR-BART1-3p as well as siDAB2 increased migration and decreased apoptosis. Meanwhile, miR-BART1-3p(i) or pcDNA3.1-DAB2 transfection decreased migration and increased apoptosis in EBV-infected GC cells. Furthermore, decreased migration by miR-BART1-3p(i) was abrogated by co-transfected siDAB2, while decreased migration by miR-BART1-3p(i) was further suppressed by a co-transfected DAB2 over-expression vector. Our data suggest that miR-BART1-3p plays an important role in the tumorigenesis of EBV-associated GC by directly targeting DAB2.

Dihydroartemisinin inhibits the growth and invasion of gastric cancer cells by regulating cyclin D1-CDK4-Rb signaling

BackgroundDihydroartemisinin (DHA), a semisynthetic derivative of artemisinin, has a broad range of biological properties, including antitumor activity. However, the mechanisms by which DHA affects the tumorigenesis of gastric carcinoma (GC) are poorly understood. Material and methodsThe targets of DHA were identified by network pharmacology, and the association of CDK4 with clinicopathological characteristics and prognosis in patients with GC was analyzed by using TCGA data. CCK8, Transwell and flow cytometric analyses, as well as a tumor xenograft model, were used to assess the effects of DHA on the growth and migration of GC cells. qRT-PCR and Western blot analyses were used to determine the effects of DHA on the cyclin D1-CDK4-Rb signaling pathway. ResultsWe identified 13 DHA targets and measured their expression of whichCDK4 expression levels were substantially higher in GC tissues than those in adjacent normal tissues, and high CDK4 expression acted as an independent prognostic factor of poor survival in patients with GC. DHA suppressed cell proliferation, migration and invasion in vitro and in vivo and induced G1 phase cell cycle arrest in a dose-dependent manner by regulating cyclin D1-CDK4-Rb signaling. ConclusionsDHA inhibits the tumorigenesis and invasion of GC by regulating cyclin D1-CDK4-Rb signaling and may provide therapeutic strategies for the treatment of GC.

LncRNA ZEB2-AS1 contributes to the tumorigenesis of gastric cancer via activating the Wnt/β-catenin pathway.

Studies have shown that long noncoding RNA Zinc finger E-box-binding homeobox 2 antisense RNA 1 (ZEB2-AS1) is involved in the progression of lung cancer, bladder cancer, and hepatocellular carcinoma. However, its role in the pathogenesis of gastric cancer remains unknown. The Wnt/β-catenin pathway contributes to the development of gastric cancer. ZEB2-AS1 expression was firstly detected in the gastric carcinoma tissue samples as well as in gastric cancer cells. Knockdown of ZEB2-AS1 was performed by ZEB2-AS1-shRNA, and the viability, migration, invasion, and apoptosis of gastric cancer cells were determined by CCK-8, scratch assay, transwell, and flow cytometry, respectively. Furthermore, levels of Ki-67, PCNA, VEGF, MMP9, epithelial-mesenchymal transition (EMT) markers (E-cadherin, Vimentin and ZEB2), cleaved caspase 3/8/9 and PARP, active β-catenin, c-Myc, cyclinD1, and AXIN2 were assayed by Western blot or real-time PCR. Additionally, the role and mechanism of ZEB2-AS1 were confirmed in a xenograft nude mouse model. We found ZEB2-AS1 expression was increased in gastric carcinoma samples, and it was correlated with tumor progression. Also, its expression was elevated in gastric cancer cells. Knockdown of ZEB2-AS1 reduced the proliferation, migration, invasion, and EMT, but increased the apoptosis of gastric carcinoma cells. Furthermore, ZEB2-AS1 downregulation remarkably suppressed the expression of Ki-67, PCNA, VEGF and MMP9, and the activation of Wnt/β-catenin signaling, whereas elevated the levels of cleaved caspase 3/8/9 and PARP in gastric cancer cells. And ZEB2 overexpression reversed the effects of ZEB2-AS1 downregulation on the proliferation, EMT and inactivation of Wnt/β-catenin signaling. Additionally, ZEB2-AS1 knockdown inhibited tumor growth, Ki-67 staining, and the expression of VEGF, MMP9, active β-catenin, c-Myc, cyclinD1, and AXIN2 in mice. In conclusion, ZEB2-AS1 promotes the tumorigenesis of gastric carcinoma that is related to the upregulation of ZEB2 and the activation of the Wnt/β-catenin pathway.

Mixed lineage kinase-4 promotes gastric carcinoma tumorigenesis through suppression of the c-Jun N-terminal kinase signaling pathway.

Mixed lineage kinase-4 (MLK-4) is an important member of the mixed-lineage family of kinases that regulates the extracellular signal-regulated kinases and c-Jun N-terminal kinase (JNK) signaling pathways. The functions and mechanisms of MLK-4 in cancer initiation and progression have not been well understood. The present study investigated the expression, function and regulatory mechanism of MLK-4 in gastric carcinoma cells. Biochemical data indicated that normal MLK-4 was downregulated, which exerted dominant negative effects on gastric carcinoma cell viability, migration and invasion. The experimental data demonstrated that MLK-4 supplement abrogated activity of these mutants and induced inhibitory effects on gastric carcinoma cell viabilty, migration and invasion in vitro and in vivo. In addition, to determine the regulatory mechanism of MLK-4, its signaling pathway was assessed in gastric carcinoma cancer cells by regulating MLK-4. The present observations indicated that restoring MLK-4 activity by supplemental MLK-4 reduced gastric carcinoma cell colony formation in vitro and suppressed tumor viability, migration and invasion in vivo. The results of the present study indicated that MLK-4 may be a potential protein for targeting gastric carcinoma by suppressing kinases, which may lead to reduction of JNK signaling and enhance therapeutic efficacy in gastric carcinoma.

Expression of Syndecan-2 in gastric adenocarcinoma and its effect on tumorigenesis in vitro

Background: Syndecan-2 (Sdc2) can affect the behavior of some cancer cells. However it is poorly understood in terms of its role in tumorigenesis of gastric carcinoma. The present study was undertaken to explore the expression and prognostic role of Sdc2 in patients with gastric adenocarcinoma tissue, and its effect on tumorigenesis in vitro. Methods: Sdc2 expression in 46 tissue samples of gastric adenocarcinoma was analyzed by immunohistochemistry. We evaluated the clinical characteristics and survival time. The expression of Sdc2 in gastric carcinoma cell lines was confirmed by real time polymerase chain reaction (RT-PCR) and western blot. Cell migration and invasion assays were carried out to investigate whether the decreased Sdc2 by siRNA transfection affected the tumorigenesis of gastric carcinoma cells. Results: The results showed that Sdc2 was expressed in tumor tissues and its expression intensity was significantly correlated with invasive and metastatic tendency (P 0.05). Through in vitro experiments, we proved that down-regulation of Sdc2 with siRNA diminished Sdc2-induced cell migration and invasion in SGC-7901 gastric carcinoma cells. Conclusions: These results suggested regulatory effects on migration and invasion by Sdc2 in gastric carcinoma cell. The up-regulation of Sdc2 expression in cancer tissue might play an important role in cancer progression of gastric adenocarcinoma.

Expression of Syndecan-2 in gastric adenocarcinoma and its effect on tumorigenesis in vitro

Background: Syndecan-2 (Sdc2) can affect the behavior of some cancer cells. However it is poorly understood in terms of its role in tumorigenesis of gastric carcinoma. The present study was undertaken to explore the expression and prognostic role of Sdc2 in patients with gastric adenocarcinoma tissue, and its effect on tumorigenesis in vitro.

Abstract LB-216: Stroma-induced up-regulation of discoidin domain receptor 1 enhances peritoneal metastasis of gastric carcinomas

Abstract Introduction: Discoidin domain receptor-1 (DDR1), a receptor tyrosine kinase, is expressed by about 50% of gastric tumor cells in previous our study and is activated by fibrillar collagens, which are major components of tumor stroma. Further, it has been proposed that peritoneal metastasis is associated with high stroma content in gastric carcinomas (GCs). In this study we investigated the contribution of DDR1 activity to peritoneal metastasis of GCs. Methods: We performed the immunohistochemistry for DDR1 and Masson’s trichrome staining for accumulation of collagen bundles in 202 human GC tissues. The human GC cell lines (MKN-28 and KATO-III) were co-cultured with GCs-associated fibroblasts (CAFs), and the expression of DDR1 and signal transduction pathways were investigated by Western blot. We evaluated CAF-induced tumorigenesis of GCs cell lines and the effects of DDR1 specific inhibitor in 3D co-culture system and peritoneal seeding in xenograft animal models. Results: High stromal collagen correlated with peritoneal recurrence (P=0.004) and was positively associated with expression of DDR1 in GC tissues (P&amp;lt;0.001). We confirmed that co-culture with CAFs elevated the expression of DDR1 in GC cell lines. CAFs also enhanced GC cell line spheroid formation in vitro in a tumor cell DDR1-dependent manner. Co-implantation of CAFs with GC cells enhanced peritoneal tumor formation in vivo, an effect that was sensitive to pharmacologic inhibition of DDR1. Conclusion: Our findings suggest that CAF-induced elevation of tumor cells DDR1 enhances peritoneal tumorigenesis of GCs and the inhibition of DDR1 signaling is an attractive strategy for the treatment of GC peritoneal metastasis. Citation Format: Hyejin Jin, In-Hye Ham, Hye Jung Oh, Dakeun Lee, Sang-Uk Han, Rolf A. Brekken, Hoon Hur. Stroma-induced up-regulation of discoidin domain receptor 1 enhances peritoneal metastasis of gastric carcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-216. doi:10.1158/1538-7445.AM2017-LB-216

MiR-376c promotes carcinogenesis and serves as a plasma marker for gastric carcinoma.

Gastric carcinoma is highly prevalent throughout the world. Understanding the pathogenesis of this disease will benefit diagnosis and resolution. Studies show that miRNAs are involved in the tumorigenesis of gastric carcinoma. An initial screening followed by subsequent validation identified that miR-376c is up-regulated in gastric carcinoma tissue and the plasma of patients with the disease. In addition, the urinary level of miR-376c is also significantly increased in gastric carcinoma patients. The plasma miR-376c level was validated as a biomarker for gastric carcinoma, including early stage tumors. The induction of miR-376c was found to enrich the proliferation, migration and anchorage-independent growth of carcinoma cells and, furthermore, the repression of the expression of endogenous miR-376c was able to reduce such oncogenic phenotypes. ARID4A gene is a direct target of miR-376c. Knockdown of endogenous ARID4A increased the oncogenicity of carcinoma cells, while ARID4A was found to be drastically down-regulated in tumor tissue. Thus, expression levels of miR-376c and ARID4A mRNA tended to be opposing in tumor tissue. Our results demonstrate that miR-376c functions by suppressing ARID4A expression, which in turn enhances the oncogenicity of gastric carcinoma cells. It seems likely that the level of miR-376c in plasma and urine could act as invaluable markers for the detection of gastric carcinoma.

A hydrophobic residue in the TALE homeodomain of PBX1 promotes epithelial-to-mesenchymal transition of gastric carcinoma.

Pre-B-cell leukemia homeobox 1 (PBX1) was originally identified as a proto-oncogene in human leukemia. Although this protein has been shown to contribute to cellular development and tumorigenesis, the role of PBX1 in gastric carcinoma (GC) remains unclear. In this study, we observed increased expression of PBX1 in GC tissues compared with adjacent normal tissues. This increase in PBX1 expression levels negatively correlated with HOXB9 mRNA expression and was also associated with malignancy and metastasis. PBX1 promoted proliferation and metastasis of GC cells both in vitro and in vivo. These phenomena were also accompanied by epithelial-to-mesenchymal transition (EMT). Additionally, we observed that PBX1 promotes the expression of tumor growth and angiogenic factors. A structural model of the PBX1-HOX complex revealed that hydrophobic binding between PBX1 and the hexapeptide motif might be required for EMT induction. This analysis also demonstrated that the Phe252 residue in the first helix of the TALE homeodomain is involved in the latter hydrophobic binding reaction. In vitro data from PBX1 mutants suggest that PBX1 cannot promote tumorigenesis of GC cells via EMT induction when Phe252 residues lose hydrophobicity. It is likely that the presence of this residue is essential in facilitating hydrophobic binding with the hexapeptide motif. These findings suggest that PBX1 may be a potential target for GC treatment and this study provides a platform to elucidate the molecular mechanisms that underpin the role of PBX1 in GC tumorigenesis.

MicroRNA-221-3p Plays an Oncogenic Role in Gastric Carcinoma by Inhibiting PTEN Expression.

Gastric carcinoma is one of the most common malignancies in men, and microRNA plays a critical role in regulating the signaling networks of gastric carcinoma tumorigenesis and metastasis. We first report the functional characteristics of miR-221-3p in gastric carcinoma. Quantification in gastric carcinoma cell lines and tumor samples reveals significantly increasing miR-221-3p expression. Moreover, a high level of miR-221-3p is correlated with a poor prognosis for gastric carcinoma patients. Ectopic miR-221-3p expression significantly promotes gastric carcinoma cell proliferation, invasion, and sphere formation, while silencing miR-221-3p significantly inhibits these abilities in gastric carcinoma cells. Tests in vivo showed that miR-221-3p significantly promotes tumor growth in xenograft mouse models. In this study, we reveal that miR-221-3p targets PTEN mRNA and downregulates PTEN, which is the possible mechanism of miR-221-3p-induced oncogenic properties. Collectively, we reveal a critical role for miR-221-3p in gastric carcinoma development and progression.

Effect of MiR-32 on gastric carcinoma tumorigenesis by targeting Kruppel-like factor 4.

76 Background: Gastric cancer (GC) is a prevalent malignant cancer worldwide and is highly lethal because of its fast growth. Currently, the comprehensive treatment is the combination of surgery, chemotherapy and radiotherapy, which has made progress in the treatment of advanced GC. However, the accuracy of current diagnostic methods is not very satisfactory. To address these limitations and improve the survival rate and reduce mortality it is necessary to identify sensitive early diagnostic markers. MiR-32 has been reported as an oncogenic microRNA in many cancers, but its role in GC is unclear. Methods: We detected miR-32 expression in clinical gastric carcinoma tissue samples and adjacent normal tissue samples from the same patient. The expression of miR-32 was also detected in 40 gastric carcinoma patients’ plasma, as compared with the plasma of 40 healthy individuals. The proliferation ability of cells was monitored by the xCELLigence Real-Time Cell Analyzer (RTCA)-MP system. Transwell insert chambers with an 8 μm diameter porous membrane (Neuro Probe, MD, USA) were used for the migration/invasion assays. Also, the plasmid construction and luciferase reporter assay, western blotting analysis and immunofluorescence cell staining were performed. Data were analyzed with SPSS v.17.0 software. Results: We detected the expression level of miR-32 in two normal gastric tissue, the GES-1 cell line, and eight gastric carcinoma cell lines. The expression of miR-32 was significantly higher in tumor tissues as compared with normal tissues, p = 0.0016. The expression of miR-32 was significantly higher in 40 gastric carcinoma patients’ plasma, as compared with the plasma of 40 healthy individuals, p = 0.004.MiR-32 promotes the proliferation, migration and invasion of GC cells. The expression of KLF4 is negatively regulated by miR-32. Knockdown of KLF4 promotes cell proliferation, migration and invasion in GC cell-lines. Conclusions: In addition to identifying upregulated miR-32 as a diagnosis biomarker in clinical GC tissue and plasma, we have defined the biological functions of miR-32 as an oncogene in GC cells and explored the molecular mechanism of miR-32 in GC cells’ aggressive phenotype.

Expression and clinical implication of S100A12 in gastric carcinoma.

S100 protein family has been implicated in multiple stages of tumorigenesis and progression in which S100A12 is one of the subtypes. However, the role of S100A12 in gastric carcinoma (GC) has not been elucidated yet. This study was aimed to investigate the expression of S100A12 in GC tissues and evaluate the clinical significance of S100A12 in GC patients. S100A12 protein was detected in 207 GC and 52 paired non-cancerous mucosal tissues by immunohistochemistry, while messenger RNA (mRNA) was investigated by Oncomine database analysis. Moreover, survival analysis was performed and the correlation between S100A12 and ubiquitin-specific protease 10 (USP10) and p53 was determined. As for tumor cells, the expression of S100A12 protein and mRNA in GC was proved to be lower than that in non-cancerous mucosa tissues (p < 0.05). Clinicopathological analysis showed that S100A12 protein was negatively associated with tumor size (p = 0.004), depth of invasion (p = 0.022), tumor node metastasis (TNM) stage (p = 0.018), Lauren classification (p < 0.000), and cell differentiation (p < 0.000). In contrast, a positive correlation was found between S100A12 and USP10 protein (p < 0.000). However, no relationship was detected between S100A12 and p53. Moreover, the survival analysis indicated that S100A12 protein was a favorable factor of prognosis of GC (p < 0.05). Although the expression of S100A12 in the stromal cells was detected higher than that in the tumor cells, no relationship between S100A12 protein in stromal cells and the clinicopathological features described above was found (p > 0.05). Our findings suggested that low expression of S100A12 might be served as a new marker in the tumorigenesis and progression of GC.

MiR-32 promotes gastric carcinoma tumorigenesis by targeting Kruppel-like factor 4

Gastric cancer (GC) is a prevalent malignant cancer worldwide and is highly lethal because of its fast growth. Currently, the clinical therapy options for GC remain limited. MiR-32 has been reported as an oncogenic microRNA in many cancers, but its role in GC is unclear. Here, we found that miR-32 was overexpressed in GC tissues compared with adjacent normal tissue, and miR-32 was higher in GC patients' plasma compared with healthy individuals. Furthermore, we have identified miR-32 to be oncogenic, by promoting gastric cell proliferation, migration and invasion. We also identified Kruppel-like factor 4 (KLF4) as a direct target of miR-32. Knockdown of KLF4 promoted proliferation, migration and invasion of GC cells. We conclude that miR-32 promotes GC cell proliferation, migration and invasion by targeting KLF4, suggesting that the miR-32-KLF4 pathway may be useful in clinical diagnosis and therapeutics.