Gastric Cancer Tumor Tissues Research Articles

High long non-coding LIFR-AS1 expression correlates with poor survival in gastric carcinoma.

Abundant evidence has demonstrated that long non-coding RNAs (lncRNAs) play key roles in the development of human neoplasms. A novel cancer-related lncRNA, leukemia inhibitory factor receptor antisense RNA 1 (LIFR-AS1), has been reported to be under-expressed in breast cancer and associated with poor prognosis, but its significance in gastric cancer (GC) remains to be determined. Therefore, we assessed the prognostic and diagnostic value of LIFR-AS1 in GC. Quantitative RT-PCR assay was used to detect the expression levels of LIFR-AS1 in GC tissues and adjacent normal tissues. The correlation between LIFR-AS1 expression and clinicopathological features was analyzed by Pearson's χ2-test. The disease-free survival and overall survival rates of GC patients were calculated by the Kaplan-Meier method. Cox regression analysis was used to assess factors related to survival. In this study, levels of LIFR-AS1 were significantly higher in GC tumor samples relative to adjacent normal tissue samples. A ROC analysis suggested LIFR-AS1 expression could be reliably used to differentiate between normal and GC tumor tissue. In addition, elevated LIFR-AS1 expression was positively correlated with more advanced and aggressive GC features, such as larger tumor size, lymphatic metastasis, and more advanced TNM stage. Survival analyses revealed that elevated LIFR-AS1 expression was correlated with worse overall survival and disease-free survival. Multivariate analysis further confirmed the relevance of LIFR-AS1 as an independent predictor of GC patient outcomes. In summary, these results indicate that the lncRNA LIFR-AS1 is a promising prognostic indicator in GC patients.

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

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

Identification of UAP1L1 as tumor promotor in gastric cancer through regulation of CDK6.

Gastric cancer (GC) is one of the most commonly diagnosed malignancies in digestive tract and its underlying molecular mechanism is still not clear, so we aimed to reveal the relationship between GC and UDP-GlcNAc pyrophosphorylase-1 like 1 (UAP1L1). The detection of UAP1L1 expression in GC tumor and normal tissues was accomplished by immunohistochemistry and demonstrated the upregulation of UAP1L1 in GC, which was statistically associated with tumor grade. GC cell models constructed via transfection of UAP1L1-silencing/overexpressing lentiviruses were employed for evaluating the effects of UAP1L1 knockdown/overexpression on GC in vitro and in vivo. The results indicated that UAP1L1 played important role in development of GC through regulating cell proliferation, colony formation, cell apoptosis and cell migration. Subsequently, CDK6 was identified as a potential target in UAP1L1 induced regulation of GC, downregulation of which exhibited similar inhibition effects on GC with UAP1L1. Moreover, it was demonstrated that the promotion of GC by UAP1L1 overexpression could be significantly attenuated or even reversed by simultaneously silencing CDK6. In conclusion, UAP1L1 was reported to be a tumor promotor in the development and progression of GC which may exert its role through regulating CDK6 and may act as a candidate of therapeutic target in treatment.

Long noncoding RNA LINC00511 promoted cell proliferation and invasion via regulating miR-124-3p/EZH2 pathway in gastric cancer.

Growing evidence has shown that long non-coding RNAs (lncRNAs) can serve as prospective markers for survival in patients with gastric cancer (GC). In this study, we mainly focused on the potential roles of LINC00511 in the development process of GC. RT-PCR was used to detect the expressions of LINC00511 and miR-124-3p in GC tumor tissues, adjacent tissues and GC cell lines. Furthermore, correlations between LINC00511 with miR-124-3p, and miR-124-3p with EZH2, were analyzed by Correlation analysis. Moreover, the overall survival (OS) of patients was analyzed using Kaplan-Meier method. Additionally, proliferation ability was measured by CCK-8 assay and invasion ability of GC cell line was detected by transwell assay. Besides, Western blot was performed to measure protein levels of GC tissues and GC cell lines. Finally, Dual-Luciferase reporter assay was performed to prove the potential binding sites between LINC00511 and miR-124-3p, miR-124-3p and EZH2. We found that LINC00511 was significantly increased in GC tissues and GC cell lines, which was associated with tumor growth, metastasis and predicted poor diagnosis of GC patients. MiR-124-3p was decreased in GC tissues and GC cell lines, which was negatively correlated with LINC00511 and EZH2. Furthermore, EZH2 was increased in GC tissues and GC cell lines, which was positively correlated with LINC00511. Moreover, LINC00511 inhibition repressed cell proliferation and invasion in MKN28 cells, the protein levels of Cyclin D1, ICAM-1, VCAM-1 and N-cadherin were repressed, while E-cadherin was increased. Besides, Luciferase gene reporter assay indicated that LINC00511 could sponge with miR-124-3p, which could directly target at EZH2, an oncogenic gene. We found that miR-124-3p/EZH2 axis regulated cell proliferation and invasion in MKN28 cells. Finally, the inhibited cell proliferation and invasion abilities were eliminated following with miR-124-3p inhibition in MKN28 cells with LINC00511 knockdown. According to the results, we found that LINC00511 was increased in GC tissues, which was associated with the poor OS in patients with GC. We uncovered a previously unappreciated LINC00511/miR-124-3p/EZH2 signaling axis in promoting cell proliferation and invasion in GC patients and GC cell lines, which suggested that it might be a potential target for treating human GC.

PTPN11 hypomethylation is associated with gastric cancer progression.

Protein tyrosine phosphatase non-receptor type 11 (PTPN11) encodes the tyrosine phosphatase SHP-2 that is overexpressed in gastric cancer (GC). In the present study, the association of PTPN11 methylation levels with the incidence of GC and its correlation with SHP-2 overexpression were investigated. The methylation levels of PTPN11 in tumor and adjacent normal tissues of 112 GC patients were assessed by quantitative methylation specific PCR (qMSP). The Cancer Genome Atlas (TCGA) public database was used to analyze the association between PTPN11 methylation and PTPN11 expression. Survival analyses were conducted in order to evaluate the prognostic value of PTPN11 methylation for GC. The results of the qMSP analysis indicated that the methylation levels of PTPN11 in GC tumor tissues were significantly decreased compared with those noted in the normal adjacent tissues (mean with standard deviation: 40.91±26.33 vs. 51.99±37.37, P=0.007). An inverse correlation between PTPN11 methylation levels and PTPN11 mRNA expression levels (P=4×10−6, r=−0.237) was noted. Subgroup analyses indicated that the association of PTPN11 hypomethylation with the incidence of GC was specific to male subjects (P=0.015), heavy drinking patients (P=0.019), patients with poor tumor differentiation (P=0.010) and patients with tumor node and metastasis (TNM) stage III+IV (P=0.008). Kaplan-Meier analyses and log-rank test suggested that PTPN11 hypomethylation was not associated with GC patient overall survival (P=0.605) and recurrence (P=0.485), although it could predict the recurrence of GC patients up to and including 60 years (≤60, P=0.049). The results indicated that PTPN11 levels were hypomethylated in GC patients. TCGA data analysis suggested that PTPN11 hypomethylation could cause an upregulation in the transcription levels of PTPN11. Although, this may explain the pattern of SHP-2 overexpression in GC, additional studies are required to verify this hypothesis. The association of PTPN11 hypomethylation with GC incidence may be specific to male patients, heavy drinking patients, patients with poor tumor differentiation and patients with TNM stage of III+IV. PTPN11 hypomethylation can be considered a biomarker for the recurrence of GC patients with an age of 60 years or lower.

FLAD1 is up-regulated in Gastric Cancer and is a potential prediction of prognosis.

Background: Gastric cancer (GC) is a common malignancy throughout the world. Biomarkers for prognosis and risk evaluation of GC are rapidly discovered. We investigated the prognostic role of FLAD1, an important protein-coding gene that affects cell cycle and survival.Methods: The expression of FLAD1 at mRNA levels in GC tumor tissues and normal tissues was mined and analyzed in Oncomine database and verified in 10 pairs of GS tissues and their adjacent normal tissues in our center by RT qPCR. The FLAD1 protein expression were detected in 106 paraffin-embedded GC tissues by immunohistochemistry (IHC). Statistical analyses were applied to evaluate the clinical significance of FLAD1. The prognostic value of FLAD1 mRNA expression was also analyzed using the Kaplan-Meier plotter (www.kmplot.com).Results: Statistics obtained from online database suggested FLAD1 mRNA was overexpressed in GC tissues. The results were further validated in 10 pairs of GS tissues and adjacent normal tissues in our center (p=0.021). IHC and survival analysis of GC samples from 106 patients showed FLAD1 was overexpressed in 63/106 (59.4%) patients and was associated to higher TNM stage (p=0.026). Multivariate analysis revealed FLAD1 was an independent prognostic factor for GC (p < 0.001). Furthermore, FLAD1 mRNA was associated to unfavorable overall survival (OS), first progression (FP), and post-progression survival (PPS) of GC (p<0.001).Conclusion: FLAD1 in GC is overexpressed at both mRNA and protein level and could be a potential biomarker for GC prognosis.

Metadherin Promotes Malignant Phenotypes And Induces Beta-Catenin Nuclear Translocation And Epithelial-Mesenchymal Transition In Gastric Cancer.

PurposeMetadherin (MTDH), as an oncogene, is associated with metastasis and poor prognosis. This study investigated MTDH expressions and development of gastric cancer (GC) cell phenotypes and the contribution of MTDH to epithelial–mesenchymal transition (EMT).Patients and methodsMTDH expression was assayed in human GC cell lines and tumor tissue from 92 GC patients. Functional experiments were performed to characterize MTDH activity. Expressions of EMT-related proteins (vimentin and E-cadherin), phosphorylated β-catenin and β-catenin were assayed by immunohistochemistry, Western blotting, immunofluorescence, and co-immunoprecipitation, respectively.ResultsMTDH expressions were higher in GC tissue than that in gastric mucosa from the same patient. MTDH overexpression was correlated with metastasis and enhanced malignant GC phenotypes, i.e., proliferation, migration, invasiveness, and chemoresistance. MTDH overexpression was associated with expressions of vimentin, E-cadherin and cancer stem-cell biomarkers including CD44, CD133, and Oct4. MTDH complexed with β-catenin and decreased phosphorylated β-catenin levels to facilitate β-catenin translocation into the nucleus and expressions of downstream genes.ConclusionMTDH overexpression in GC cells is associated with EMT and development of cancer stem cell malignant phenotypes and affects the subcellular translocation of β-catenin. The results warrant investigation of the prognostic value of MTDH in GC and as a therapeutic target.

CLIC4 abrogation promotes epithelial-mesenchymal transition in gastric cancer.

Chloride intracellular channel protein 4 (CLIC4) has been implicated in different types of cancers, but the role of CLIC4 in the development of gastric cancer (GC) remains unknown. We analyzed the expression of CLIC4 in 102 pairs of gastric adenocarcinomas by western blot and real-time PCR. Our data revealed that the expression of CLIC4 is reduced in GC tumor tissues compared with adjacent normal tissues. The expression levels of CLIC4 correlate inversely with the clinical stage of GC. CLIC4 expression is lowest in MKN45 cells, which have the highest tumorigenic potential and express the highest levels of cancer stem cell markers CD44 and OCT4, compared with N87 and AGS cells. Exogenous overexpression of CLIC4 downregulated the expression of CD44 and OCT4, and inhibited migration, invasion and epithelial-mesenchymal transition (EMT). Moreover, anchorage-independent growth of GC cells was decreased and the cells became more sensitive to 5-fluorouracil and etoposide treatment when CLIC4 was overexpressed. The ability of N87 cells to form tumors in nude mice was enhanced when CLIC4 was silenced. We, for the first time, demonstrate that CLIC4 suppresses tumor growth by inhibiting cancer cell stemness and EMT.

BATF2 inhibits chemotherapy resistance by suppressing AP-1 in vincristine-resistant gastric cancer cells.

Chemotherapy remains the primary treatment used to improve overall survival and quality of life for patients with gastric cancer (GC); however, multidrug resistance is a major reason underlying failure of chemotherapy. Drug resistance (DR) can arise because of molecular changes inhibiting drug-target interactions; for example, overexpression of drug efflux pumps, such as P-gp, mediated by the activation of AP-1. BATF2 is a suppressor of AP-1; therefore, this study aimed to determinehow BATF2 interacts with AP-1to inhibit DR in GC cells. Expression of BATF2 in drug-responsive and non-responsive GC tumor tissues was evaluated by quantitative PCR and western blotting. Further, expression levels of BATF2- and AP-1-related genes were confirmed in vincristine-resistant SGC7901/VCR cells treated with cisplatin or 5-fluorouracil. A BATF2 overexpression system was established in SGC7901/VCR cells, and then AP-1 also overexpressed in the cells with upregulated BATF2 levels. Further, an AP-1 knockdown system was generated in SGC7901/VCR cells. MTT and flow cytometry assays were performed in the BATF2/AP-1 overexpression system, to evaluate cell proliferation, cell cycle effects, and apoptosis, and the expression of various proteins was detected by western blotting in AP-1/BATF2 overexpression cells. Finally, the effects of BATF2 overexpression in an in vivo nude mouse GC model were evaluated. We found that BATF2 was overexpressed in tissues from patients with non-responsive GC and the VCR resistance cell line, SGC7901/VCR, while levels of c-Fos and c-Jun were reduced in the SGC7901/VCR cell line. BATF2 overexpression suppressed levels of AP-1 and P-gp. Further, our data demonstrate that cell proliferation is suppressed, and the cell cycle and apoptosis are induced in SGC7901/VCR cells overexpressing both AP-1 and BATF2. Overexpression of AP-1 restored levels of genes downstream of AP-1 in BATF2 overexpressing cells. Compared with controls, tumor growth of SGC7901/VCR cells in nude mice was suppressed in the BATF2 overexpression group. AP-1 down-regulation by BATF2 overexpression or AP-1 knockdown can inhibit DR in GC cells. These findings suggest that BATF2 inhibits DR in SGC7901/VCR GC cells by down-regulating AP-1 expression.

Involvement of NF-κB signaling pathway in the regulation of PRKAA1-mediated tumorigenesis in gastric cancer

AMP-activated alpha 1 catalytic subunit (PRKAA1) is one of the subunits of the mammalian 5′-AMP-activated protein kinase (AMPK) playing an important role in maintaining intracellular energy metabolism and associating with the risk of gastric cancer (GC). This paper aims to uncover the influences of PRKAA1 on the tumorigenesis of GC, as well as the underlying mechanisms. We found that Helicobacter pylori (H. pylori) infection markedly increased p-NF-κBp50 and NF-κBp50 expression, along with the PRKAA1 expression, which was inhibited by NF-κBp50 knockdown. NF-κBp50 and PRKAA1 expression were lower in non-tumor gastric tissues compared with that in GC tumor tissues. Up-regulation of PRKAA1 expression was correlated with poor survival in GC patients. MKN-45 and BGC-823 cells stably knockdown of PRKAA1 were transplanted into nude mice and observed the decreased cell metastasis in the lungs. PRKAA1 knockdown in GC cells showed significant decreases in the cell invasion and migration and inhibited MMP-2 expression and NF-κB activation, whereas PRKAA1 involved in NF-κBp50 mediated GC cell invasion and migration. In conclusion, our findings suggest the involvement of NF-κBp50 in the regulation of PRKAA1 in GC tumorigenesis.

Piperlongumine potentiates the antitumor efficacy of oxaliplatin through ROS induction in gastric cancer cells.

Oxaliplatin is one of the most commonly used chemotherapeutic agents in the treatment of various cancers, including gastric cancer. It has, however, a narrow therapeutic index due to its toxicity and the occurrence of drug resistance. Therefore, there is a pressing need to develop novel therapies to potentiate the efficacy and reduce the toxicity of oxaliplatin. Piperlongumine (PL), an alkaloid isolated from Piper longum L., has recently been identified as a potent agent against cancer cells in vitro and in vivo. In the present study, we investigated whether PL can potentiate the antitumor effect of oxaliplatin in gastric cancer cells. Cellular apoptosis and ROS levels were analyzed by flow cytometry. Thioredoxin reductase 1 (TrxR1) activity in gastric cancer cells or tumor tissues was determined using an endpoint insulin reduction assay. Western blotting was used to analyze the expression levels of the indicated proteins. Nude mice xenograft models were used to test the effects of PL and oxaliplatin combinations on gastric cancer cell growth in vivo. We found that PL significantly enhanced oxaliplatin-induced growth inhibition in both gastric and colon cancer cells. Moreover, we found that PL potentiated the antitumor effect of oxaliplatin by inhibiting TrxR1 activity. PL combined with oxaliplatin markedly suppressed the activity of TrxR1, resulting in the accumulation of ROS and, thereby, DNA damage induction and p38 and JNK signaling pathway activation. Pretreatment with antioxidant N-acetyl-L-cysteine (NAC) significantly abrogated the combined treatment-induced ROS generation, DNA damage and apoptosis. Importantly, we found that activation of the p38 and JNK signaling pathways prompted by PL and oxaliplatin was also reversed by NAC pretreatment. In vivo, we found that PL combined with oxaliplatin significantly suppressed tumor growth in a gastric cancer xenograft model, and effectively reduced the activity of TrxR1 in tumor tissues. Remarkably, we found that PL attenuated body weight loss evoked by oxaliplatin treatment. Our data support a synergistic effect of PL and oxaliplatin and suggest that application of its combination may be more effective for the treatment of gastric cancer than oxaliplatin alone.

PCAT-1 contributes to cisplatin resistance in gastric cancer through epigenetically silencing PTEN via recruiting EZH2.

The aim of this study was to investigate the functional role and the underlying molecular mechanism of long noncoding RNA (lncRNA) prostate cancer-associated transcript 1 (PCAT-1) in cisplatin resistance of gastric cancer (GC). Our results indicated that PCAT-1 was overexpressed in CDDP-resistant GC tumor tissues and cell lines. High expression of PCAT-1 was closely correlated with short overall survival in patients with GC. Downregulation of PCAT-1 resensitized CDDP-resistant GC cells to cisplatin. In addition, PCAT-1 epigenetically silenced PTEN through binding to the histone methyltransferase enhancer of zeste homolog 2 (EZH2), thus increasing H3K27me3. More importantly, PTEN silencing counteracted PCAT-1 knockdown-mediated enhancement in cisplatin sensitivity of CDDP-resistant GC cells. In summary, PCAT-1 led to cisplatin resistance in GC cells through epigenetically suppressing PTEN expression, providing a novel therapeutic strategy for GC patients with chemoresistance.

&lt;p&gt;Upregulation of family with sequence similarity 83 member D expression enhances cell proliferation and motility via activation of Wnt/β-catenin signaling and predicts poor prognosis in gastric cancer&lt;/p&gt;

Background/aimsGastric cancer (GC) is the third most common cause of cancer-related death worldwide. The molecular mechanisms underlying the progression of gastric cancer are still not fully elucidated. In this study, we focused on exploring the role of family with sequence similarity 83, member D (FAM83D) in gastric cancer progression.MethodsThe expression of FAM83D in GC tissues was detected by immunohistochemistry (IHC) staining. FAM83D knockdown or overexpression were constructed in AGS and SGC-7901 cells with two distinct siRNA duplexes and lentivirus infection, respectively, to explore the role of FAM83D in gastric cancer progression. Nude mouse xenograft assay was used to further explore the role of FAM83D in tumorigenesis in vivo.ResultsWe found that FAM83D mRNA and protein levels were higher in human GC tumor tissues and in GC cell lines, compared with the adjacent normal tissues and non-malignant gastric epithelial cell lines, respectively, and that higher FAM83D expression was correlated with worse overall survival (p<0.0001) and disease-free survival (p<0.0001) in GC patients. Additionally, our results showed that FAM83D overexpression significantly enhanced the proliferation, clonogenicity, and motility of GC cells, whereas FAM83D depletion caused a dramatic increase in the number of cells arrested at the G1 phase of the cell cycle. Consistent with these findings from in vitro experiment, our data also indicated that FAM83D knockdown significantly repressed GC tumor growth in vivo. Furthermore, we demonstrated that FAM83D depletion was associated with reduced Wnt/β-catenin signaling.ConclusionsThis study suggested that FAM83D overexpression enhanced the proliferation, clonogenicity, and motility of GC cells by activating Wnt/β-catenin signaling, and FAM83D may be a promising diagnostic and therapeutic target for human GC.

Dysregulated N6-methyladenosinemethylation writer METTL3 contributes to the proliferation and migration of gastric cancer.

Accumulating evidence implies that N6-methyladenosine (m6A) methylation participated in the tumorigenesis of gastric cancer (GC). Here we synthetically analyzing the prognostic value and expression profile of seven m6A methylation-relevant genes through silico analysis of sequencing data downloaded from The Cancer Genome Atlas, Kaplan-Meier plotter, and Gene Expression Omnibus database. We explored the methyltransferase-like 3 (METTL3) expression in GC cell line and tumor tissues by reverse transcription quantitative polymerase chain reaction and western blot analysis. The m6A methylation status of total RNA was measured by m6A RNA methylation quantification kit. Small interfering RNA was used to establish METTL3 knockdown cell lines. We also measure the proliferation and migration capability GC cell. Furthermore, we detect the epithelial cell mesenchymal transition marker and m6A methylation level after METTL3 knock down. Our result revealed that METTL3 was significantly increased in GC tissues compared with control in big crowd data sets. Survival analysis showed that METTL3 serve as a poor prognostic factor for GC patients. The expression level of METTL3 gradually increased with the progress of tumor stage and grade. GFI1 is an important transcription factor associated with METTL3. We verified the up-trend of METTL3 in messenger RNA and protein expression and observed a significant increase in the m6A methylation status of total RNA in the GC cells and tissues. METTL3 knockdown inhibited total RNA m6A methylation level, as well as cell proliferation and migration capacity. Moreover, METTL3 knockdown decreased α-smooth muscle actin. Taken together, our finding revealed that m6A methylation writer METTL3 serve as an oncogene in tumorigenesis of GC.

Upregulation of LSD1 promotes migration and invasion in gastric cancer through facilitating EMT.

BackgroundGastric cancer (GC) is a common malignant tumor of the digestive system. In addition, GC metastasis is an extremely complicated process. A previous study has found that lysine-specific demethylase 1 (LSD1) is abnormal expression in a variety of cancers and its overexpression correlates with aggressive disease and poor outcome.MethodsqRT-PCR and Western blot assays were used to assess the expression of LSD1 in GC tissue samples and cell lines. Colony formation assay, CCK-8 assay, scratch-wound assay and transwell invasion, were performed to determine the effect of LSD1 on cell proliferation and migration as well as invasion in GC.ResultsOur results show that LSD1 was up-regulated in GC tumor tissues and cell lines, and high expression level of LSD1 was found to be positively correlated with tumor size, lymph node metastasis and pathological grade. Moreover, LSD1 promoted cell proliferation, migration and invasion of GC. In addition, LSD1 regulated E-cadherin expression through demethylating H3K4me2, thereby promoting EMT in GC.ConclusionOur work indicated that LSD1 may be used as a potential target of gastric cancer.

Association of High Expression Levels of SOX2, NANOG, and OCT4 in Gastric Cancer Tumor Tissues with Progression and Poor Prognosis.

Expression of the essential regulator genes, SOX2, NANOG, and OCT4, so-called as stemness factors, is prerequisite for the tumorigenic capability of cancer stem cells (CSCs) and their potential role in the formation and progression of various human cancers. In this study, the expression levels of SOX2, NANOG, and OCT4 were quantified by a qRT-PCR method in 100 gastric cancer tumor tissues vs the paired adjacent normal tissues. Then, the relationship between the expression of the three genes in gastric cancer tumor tissues and the clinicopathological characteristics and overall survival of patients was investigated. Higher expression levels of SOX2, NANOG, and OCT4 were found in gastric cancer tumor tissues compared with those in paired adjacent normal tissues (P = 0.0001). Overexpression of the mentioned genes in gastric cancer tumor tissues was resolved to be significantly associated with tumor size (P < 0.05), TNM stage (P = 0.001), tumor grade (P < 0.01), and shortened overall survival time (P = 0.0001). These findings indicted that the stemness factors SOX2, NANOG, and OCT4 are significantly overexpressed in gastric cancer and may serve as potential biomarkers of gastric cancer progression and prognosis.

Exosomal miRNA-139 in cancer-associated fibroblasts inhibits gastric cancer progression by repressing MMP11 expression.

Solid tumors consist of various types of stromal cells in addition to cancer cells. Cancer-associated fibroblasts (CAFs) are a major component of the tumor stroma and play an essential role in tumor progression and metastasis in a variety of malignancies, including gastric cancer. However, the effects of CAFs on gastric cancer cells' progression and metastasis are not well studied. Here we show that matrix metalloproteinase 11 (MMP11) in exosomes secreted from CAFs can be delivered into gastric cancer cells. Gastric CAFs promote gastric cancer cell migration partially through exosomal MMP11. Moreover, MMP11 is overexpressed in exosomes purified from plasma of gastric cancer patients and tumor tissues and associated with overall survival of gastric patients. We also find that MMP11 is negatively regulated by exosomal miR-139 in the CAFs of gastric cancer. Exosomal miR-139 inhibits tumor growth and metastasis of gastric cancer cells by decreasing the expression of MMP11 in vitro and in vivo. Thus, we propose that exosomal miR-139 derived from gastric CAFs could inhibit the progression and metastasis of gastric cancer by decreasing MMP11 in tumor microenvironment.

Immunohistochemical Analysis of LGR5 and TROY Expression in Gastric Carcinogenesis Demonstrates an Inverse Trend

Background:Two of the Wnt signaling pathway target genes, tumor necrosis factor receptor family member (TROY) and leucine-rich G-protein coupled receptor (LGR5), are involved in the generation and maintenance of gastrointestinal epithelium. A negative modulatory role has recently been assigned to TROY, in this pathway. Here, we have examined their simultaneous expression in gastric carcinogenesis. Methods:Tumor and paired adjacent tissues of intestinal-type gastric cancer (GC) patients (n = 30) were evaluated for LGR5 and TROY expression by immunohistochemistry. The combination of the percentage of positively stained cells and the intensity of staining was defined as the composite score and compared between groups. The obtained findings were re-evaluated in a mouse model. Results:TROY expression in the tumor tissue was significantly lower than that of the adjacent tissue (2.5 ± 0.9 vs. 3.3 ± 0.9, p = 0.004), which was coincident with higher LGR5 expression (3.6 ± 1.1 vs. 2.7 ± 0.9, p = 0.001). This observation was prominent at stages II/III of GC, leading to a statistically significant mean difference of expression between these two molecules (p = 0.005). In the H. pylori infected-mouse model, this inverse expression was observed in transition from early (8-16 w) to late (26-50 w) time points, post treatment (p = 0.002). Conclusion:Our data demonstrates an inverse trend between TROY down-regulation and LGR5 up-regulation in GC tumors, as well as in response to H. pylori infection in mice. These findings support a potential negative modulatory role for TROY on LGR5 expression.

MAEL Cancer-Testis Antigen as a Diagnostic Marker in Primary Stages of Gastric Cancer with Helicobacter pylori Infection.

Gastric cancer (GC) is the third leading cause of cancer related deaths in the world. Cancer testis antigens (CTAs) are involved in tumor progression of various cancers. These markers have not any expression or minimally expression in normal tissues, highlighting them as efficient methods for molecular targeted therapy. In the present study, we assessed the role of MAEL as a CTA in biology of GC and risk of Helicobacter Pylori (H pylori) infection. Levels of MAEL mRNA expression in 80 GC tumor tissues were compared to their corresponding normal margins using the real-time polymerase chain reaction. There was a significant correlation between MAEL expression and tumor stage (p = 0.050). There were also significant correlations between MAEL expression and tumor grade (p = 0.015) and depth of invasion (p = 0.030) among the H pylori negative cases. MAEL is probably associated with aggressiveness of primary-stage tumors and can be introduced as an efficient marker for the early detection and also H pylori infected tumors in GC patients.

Tumor suppressor PLZF regulated by lncRNA ANRIL suppresses proliferation and epithelial mesenchymal transformation of gastric cancer cells.

Promyelocytic leukemia zinc finger (PLZF) plays important roles in tumorigenic and developmental processes of various types of cancers. However, the expression of PLZF in gastric cancer (GC) has not been reported. The aim of the present study was to investigate the expression level and potential status of PLZF in GC as well as its possible mechanism. In the present study, we found that PLZF was downregulated in the majority of GC cell lines and tumor tissues and that alteration of PLZF expression was closely correlated with a malignant phenotype, epithelial‑mesenchymal transformation and overall survival. Evaluation of in vitro proliferation, colony information, migration and invasion indicated that PLZF gene transduction induced a less malignant phenotype, which was also confirmed through in vivo studies performed in athymic nude mice. Furthermore, we assessed the expression levels of the lncRNA ANRIL in GC and found that it was negatively associated with the level of PLZF and that ANRIL indirectly methylated PLZF to suppress its expression via binding with polycomb repressive complex 2. When GC cells were treated with the methylation inhibitor 5‑Aza‑2'‑deoxycytidine, the expression of PLZF increased, which further confirmed that PLZF was methylated. These results indicated that constitutive ANRIL activation was a possible cause of the lack of PLZF expression in GC cells. Coupled deregulation of PLZF and ANRIL may account for most of the alterations described in GC, and PLZF may become a potential target of GC therapy.