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

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

PRRX1 promotes lymph node metastasis of gastric cancer by regulating epithelial-mesenchymal transition.

BACKGROUND: Gastric cancer has multiple metastasis pathways, of which lymph node metastasis plays a dominant role. However, the specific mechanism of lymph node metastasis is still not unclear. METHODS: The bioinformatics technology was utilized to mine gene chip data related to gastric cancer and Epithelial-Mesenchymal Transition (EMT) in a high-throughput gene expression database (Gene Expression Omnibus, GEO), we screened out all genes that have differential expression levels in gastric cancer tissues and in adjacent normal gastric mucosa tissues. The corresponding function package of R language software were performed for gene annotation and cluster analysis, then enrichment analysis of genes with differential expression and protein interaction network diagram for correlation analysis were performed, we finally screened out the paired related homeobox 1 gene (PRRX1) related to EMT. Next, we collected 65 metastatic lymph node samples and 93 gastric cancer tissue samples. The expression levels of PRRX1 and EMT-related protein E-cadherin (E-ca) and vimentin (Vim) in gastric cancer tissues and metastatic lymph node tissues were determined by immunohistochemistry (IHC) staining of streptavidin-peroxidase (SP). The expression differences of PRRX1, E-ca and Vim in gastric cancer tissues and metastatic lymph node tissues as well as the correlation were analyzed by the experimental data, and the clinical significance was analyzed in combination with the clinicopathological data. RESULTS: The PRRX1 expression levels in gastric cancer tissues are significantly higher than that in adjacent normal gastric mucosa tissues. The positive expression rates of PRRX1, Vim and E-ca in gastric cancer and in metastatic lymph node tissues were significantly different. Comparing with that in gastric cancer, expression of PRRX1 and Vim was significantly down-regulated, and E-ca expression was significantly up-regulated in metastatic lymph nodes. CONCLUSION: PRRX1 may promote lymph node metastasis of gastric cancer by regulating EMT, and then affect the prognosis of patients. PRRX1 may be used as a new biological indicator to predict or prevent lymph node metastasis in gastric cancer.

Expression and clinical significance of paired- related homeobox 1 and Smad2 in gastric cancer.

BACKGROUND: China has a high incidence rate and low survival rate of gastric cancer. Therefore, there is a great need to further identify novel oncogenes and clinically applicable molecular targets for the diagnosis and treatment of this disease. METHODS: Expressions of PRRX1, Smad2, epithelial phenotype marker E-cadherin, and interstitial phenotype vimentin protein in a sample of 64 gastric carcinoma and adjacent nontumorous tissues were detected by immunohistochemistry. Their relationship and correlations with clinicopathological features were analyzed. RESULTS: The positive rates of PRRX1, Smad2, E-cadherin, and vimentin protein in primary tumors were 60.94% (39/64), 59.38% (38/64), 34.38%(22/64), and 64.06% (41/64), respectively. A significant correlation was found among the expression of PRRX1, Smad2, E-cadherin, and vimentin (P < 0.05). Expression of the PRRX1, Smad2, and vimentin protein in gastric cancer tissue was correlated with Borrmann classification, lymph node-positive number, the degree of differentiation, depth of tumor invasion, and serum pepsinogen I (PGI) level (P < 0.05), but not with age, sex, serum carcinoembryonic antigen, serum CA199, or PGI/PGII (P > 0.05). CONCLUSION: The positive rate of PRRX1 protein expression was positively correlated with the protein expression of Smad2 and vimentin, but negatively correlated with E-cadherin protein. PRRX1, Smad2, and vimentin proteins are associated with Borrmann type, lymph node positives, histologic grade, depth of tumor invasion, and serum PGI levels, all of which contribute to a poor prognosis for patients with gastric cancer.

Relationship between PRRX1, circulating tumor cells, and clinicopathological parameter in patients with gastric cancer.

PURPOSE: Paired related homoeobox 1 (PRRX1) has been identified as a new epithelial-mesenchymal transition (EMT) inducer in gastric cancer and that PRRX1 upregulation is closely correlated with gastric cancer metastasis. In addition, circulating tumor cells (CTCs) play an important role in the process of gastric cancer's distant metastasis. Our study aimed to correlate Prrx1, CTCs and the clinicopathological parameters in primary gastric cancer patients. METHODS: Expressions of PRRX1 in a sample of 95 gastric carcinoma and adjacent nontumorous tissues were detected by immunohistochemistry. Then the integrated subtraction enrichment and immunostaining fluorescence in situ hybridization (SET-imFISH) platform were applied to detect and characterize CTCs in patients with gastric cancer. Finally, their correlations with clinicopathological parameters could be analyzed. RESULTS: The positive rate of PRRX1in gastric cancer was 56.84% and the rate was 36.84% in adjacent normal gastric mucosa, which was confirmed to be statistically significant. In the meantime, both the expression of PRRX1 and the positive rate of CTCs did not significantly correlate with age, gender or histologic type (p>0.05) but significantly related to tumor size, grade of differentiation, lymph node invasion, vascular invasion, metastasis status, depth of tumor invasion, lymph node metastasis and TNM stage (p<0.05). Besides, there was a close relationship between the PRRX1 of gastric cancer and the CTCs of peripheral blood specimens of cancer patients with the correlation coefficient 0.322. CONCLUSION: Gastric cancer tissues showed that the level of PRRX1 expression was higher compared to the adjacent normal gastric mucosa. Both the expression of PRRX1 and the positive rate of CTCs significantly correlated with clinicopathological parameters. In addition, there was a positive correlation relationship between the PRRX1 of gastric cancer and the CTCs of peripheral blood specimens of cancer patients. These findings demonstrate that higher-level expression of PRRX1 in gastric cancer tissues increased the amount of CTCs in peripheral blood and facilitated the invasion and metastasis in patients with gastric cancer. Meanwhile, it gave some clues to clinical treatment. CTCs may contribute to promotion in diagnosis, therapy monitoring and prognosis of gastric cancer.

High expression level of long non-coding RNA HOTAIR is associated with poor overall survival in gastric cancer patients: evidence from meta-analysis.

PURPOSE: Although several studies have investigated the association between the development of gastric cancer (GC) and the expression level of long non-coding (lnc) RNA HOTAIR, no clear evidence about whether its expression is associated with the overall survival (OS) of GC patients exists. In this study we tried to explore the association between lncRNA HOTAIR expression levels with OS and other clinical features in GC patients. METHODS: Databases including PubMed, EMBASE and the Cochrane Library were used to search eligible studies. The quality of included studies was assessed according to reporting recommendations for tumor marker prognostic studies (REMARK). The association between the expression level of lncRNA HOTAIR and OS was evaluated by calculating the pooled hazard ratio (HR) and 95% confidence interval (95% CI) using the STATA software, version 12.0. RESULTS: A total of 9 studies involving 740 GC and 768 normal gastric tissues were included in this meta-analysis. The average score of quality assessment was 18.89±1.08, (range 16.5-20). The results indicated that high expression levels of lncRNA HOTAIR were associated with poor OS in GC patients (pooled HR: 1.43, 95% CI:1.17-1.76, p=0.000). Subgroup analyses showed that elevated expression of lncRNA HOTAIR was significantly associated with poor OS in Chinese GC patients (HR=1.414, 95%CI: 1.120-1.785, p=0.000), and not treated GC patients (HR=1.464, 95%CI: 1.179-1.817, p=0.001). Subgroup analyses also revealed that some GC patients features (e.g. T3-T4, III/IV stage, differentiation) were associated with an unfavorable outcome. CONCLUSIONS: High expression level of lncRNA HOTAIR is associated with a poor OS in GC patients. Thus, lncRNA HOTAIR might be a potentially useful independent prognostic biomarker for GC.

Synchronous double primary gastric and endometrial cancer: a case report and literature review.

Multiple primary malignant neoplasms (MPMN) are two or more malignancies in an individual without any relationship between the tumors. In recent years, increasing number of cases were reported. However, Synchronous double primary gastric and endometrial cancer are relatively rare to be reported. Here we present a rare case of synchronous double cancer involving the stomach and endometrium, which is resected simultaneously and received six times chemo. After reviewing lots of literatures at home and abroad, we discuss the risk factors, the diagnostic criteria, the treatment modalities and the prognosis of these rare MPMN. Although a number of risk factors have been proposed in a mass of literatures, but the mechanism of MPMN is still unclear. We didn't discover a detailed explanation for the mechanism of MPMN from our patient. Therefore, further research should focus on the etiology and mechanism of MPMN.

[S-Adenosylmethionine Inhibits Expression of Vascular Endothelial Growth Factor-C Protein and Cellular Proliferation in Gastric Cancer].

OBJECTIVE: To explore inhibitory effects of S-adenosylmethionine on vascular endothelial growth factor-C (VEGF-C) protein and cellular proliferation in gastric cancer by regulating methylation status of VEGF-C promoter. METHODS: MTT analyses and nude mice model were employed to examine the effects of S- adenosylmethionine on inhibiting gastric cancer growth in vitro and in vivo. The protein expression of VEGF-C in gastric cancer cells was assessed by Western blot. The methylation status of VEGF-C promoter was assessed by bisulfite genomic DNA sequencing analysis. RESULTS: VEGF-C promoter was hypomethylated in MGC803 and SGC7901. The treatment of S-adenosylmethionine resulted in a heavy hypermethylation of VEGF-C promoter, which consequently down regulated protein level of VEGF-C. S-adenosylmethionine effectively inhibited the growth of gastric cancer cells in vitro and in vivo (P<0. 05). CONCLUSION: S-adenosylmethionine can effectively reverse DNA hypomethylation on VEGF-C promoter which down-regulates VEGF-C protein expression and inhibit gastric cancer growth.

Alterations in vitamin D signaling pathway in gastric cancer progression: a study of vitamin D receptor expression in human normal, premalignant, and malignant gastric tissue.

Amount of studies in cells and animal models have proved vitamin D has multifarious antitumor effects. However, epidemiological studies showed inconsistent result on gastric cancer. The antitumor role is mainly mediated by the vitamin D receptor (VDR). Our hypothesis is that VDR may be abnormally (poorly) expressed in gastric cancer tissue. Present study is aimed at discovering and analyzing VDR expression in a series of human gastric tissues, including normal, premalignant, and malignant gastric tissue, and correlated VDR to the clinicopathological parameters of gastric cancer patients. VDR expression was detected by immunohistochemistry. The χ(2) test was used to analyze the VDR expression as well as the relationship between VDR and the clinicopathological factors of gastric cancer patients. Compared with normal (82.61%) and premalignant tissues (73.64%), VDR was lower expressed in cancer tissues (57.61%), with a statistically significant difference (P = 0.001). Among cancer tissues, VDR was higher expressed in well and moderate differentiated tissues contrasted with tissues with poor differentiation, and higher expressed in small tumors (< 5 cm) compared with large tumors (≥ 5 cm), with a statistically significant difference respectively (P = 0.016, P = 0.009). A decline linear trend appeared when analyzing the statistical difference of VDR expression among normal, premalignant, and malignant gastric tissues. VDR expression has been on the decline from the premalignant stage, finally low expressed in gastric cancer tissues, especial in poorly differentiated tissues. VDR could be a potential prognostic factor for patients with gastric cancer.

Expression of MACC1 and c-Met in human gastric cancer and its clinical significance.

BACKGROUND: Recent studies have suggested that the metastasis-associated colon cancer1 (MACC1) gene can promote tumor proliferation, invasion and metastasis through an upregulation of c-Met expression. However, its role in gastric cancer is controversial. Our study investigated expression of MACC1 and c-Met in gastric cancer, as well as correlated this with clinicopathological parameters. METHODS: Expressions of MACC1 and c-Met protein in a sample of 98 gastric carcinoma and adjacent nontumorous tissues were detected by immunohistochemistry. Their relationships and correlations with clinicopathological features were analyzed. RESULTS: The positive rates of MACC1 and c-Met protein in primary tumors were 61.22% and 59.18%, respectively. A significant correlation was found between expression of MACC1 and c-Met (P<0.05). Expression of the MACC1 protein in gastric cancer tissue was correlated with lymph node metastasis (χ2 = 10.555,P = 0.001), peritoneal metastasis (χ2 = 5.694, P = 0.017), and hepatic metastasis (χ2 = 4.540,P = 0.033), but not with age, gender, tumor size, location, clinical stage or the distant metastases (P>0.05). CONCLUSION: The positive rate of MACC1 protein expression was related to the protein expression of c-Met. Both had a correlation with the presence of peritoneal metastasis, lymph node metastasis and hepatic metastasis, all of which contribute to a poor prognosis for gastric cancer patients.

RNAi-mediated gene silencing of vascular endothelial growth factor-C inhibits tumor lymphangiogenesis and growth of gastric cancer in vivo in mice.

Overexpression of vascular endothelial growth factor-C (VEGF-C) has been implicated as a critical molecular signal in tumor development by promoting intratumoral lymphangiogenesis. The aim of this study was to explore whether small hairpin RNA (shRNA) targeting VEGF-C could inhibit gastric cancer lymphangiogenesis and tumor growth. Plasmid-mediated expression of VEGF-C-shRNA was employed to silence VEGF-C gene expression in human SGC-7901 cell lines. The inhibition of the target gene expression was quantified by real-time quantitative polymerase chain reaction, Western blotting, and enzyme-linked immunosorbent assay. In vitro, the cell viability was determined by MTT assay, flow cytometry analysis, and migration assay. After VEGF-C knockdown was confirmed, the stable cells were inoculated into nude mice. Tumor growth, lymph vessel density (LVD), and microvascular density were compared for mice administered either VEGF-C-shRNA or control. VEGF-C-shRNA causes effective and specific downregulation of VEGF-C expression (P<0.05). The migration activity of SGC-7901 cells was attenuated in vitro (P<0.05). Tumor growth rate and LVD was suppressed in vivo (P<0.05). VEGF-C-shRNA effectively suppressed gastric cancer cell migration in vivo, retards tumorigenicity, and lymphangiogenesis in nude mice.