OBJECTIVES: Gastric cancer is a common cancer of the digestive system. Long non-coding RNA (lncRNA) plays an important role in the formation and development of gastric cancer. This study aims to investigate the effect of long non-coding lncRNA 114227 on biologic behaviors in gastric cancer cells. METHODS: The experiment was divided into 4 groups: a negative control (NC) group, a lncRNA 114227 small interference (si-lncRNA 114227) group, an empty vector (Vector) group, and an overexpression vector (OE-lncRNA 114227) group. The expressions of lncRNA 114227 in gastric mucosa and gastric cancer tissues, gastric mucosal epithelial cells and different gastric cancer strains were determined by real-time reverse transcription PCR (real-time RT-PCR).The proliferation were detected by CCK-8 assay in gastric cancer cells. The epithelial-mesenchymal transformation (EMT) was utilized by Transwell assay, scratch healing assay, and Western blotting in gastric cancer cells. The effect of lncRNA 114227 on proliferation of gastric cancer cells was detected by tumor bearing experiment in nude mice in vivo. RESULTS: The expression level of lncRNA 114227 in the gastric cancer tissues was significantly lower than that in the gastric mucosa tissues, and in 4 kinds of gastric cancer strains was all significantly lower than that in gastric mucosal epithelial cells (all P<0.01). In vitro, the proliferation and migration abilities of gastric cells were significantly reduced after overexpressing lncRNA 114227, and cell proliferation and migration were enhanced after silencing lncRNA 114227 (all P<0.05). The results of in vivo subcutaneous tumorigenesis in nude mice showed that the tumorigenic volume of the tumor-bearing mice in the OE-lncRNA 114227 group was significantly smaller than that of the Vector group, and the tumorigenic quality was lower than that of the Vector group (P<0.05), indicating that lncRNA 114227 inhibited tumorigenesis. CONCLUSIONS The expression of lncRNA 114227 is downregulated in gastric cancer gastric cancer tissues and cell lines. LncRNA 114227 may inhibit the proliferation and migration of gastric cancer cells through EMT process.
Animals ; Mice ; RNA, Long Noncoding/metabolism* ; Stomach Neoplasms/pathology* ; Mice, Nude ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Carcinogenesis/genetics* ; Cell Movement/genetics* ; Epithelial-Mesenchymal Transition/genetics* ; Gene Expression Regulation, Neoplastic ; Apoptosis/genetics*

As an important part of tumor microenvironment, neutrophils are poorly understood due to their spatiotemporal heterogeneity in tumorigenesis. Here we defined, at single-cell resolution, CD44-CXCR2- neutrophils as tumor-specific neutrophils (tsNeus) in both mouse and human gastric cancer (GC). We uncovered a Hippo regulon in neutrophils with unique YAP signature genes (e.g., ICAM1, CD14, EGR1) distinct from those identified in epithelial and/or cancer cells. Importantly, knockout of YAP/TAZ in neutrophils impaired their differentiation into CD54+ tsNeus and reduced their antitumor activity, leading to accelerated GC progression. Moreover, the relative amounts of CD54+ tsNeus were found to be negatively associated with GC progression and positively associated with patient survival. Interestingly, GC patients receiving neoadjuvant chemotherapy had increased numbers of CD54+ tsNeus. Furthermore, pharmacologically enhancing YAP activity selectively activated neutrophils to suppress refractory GC, with no significant inflammation-related side effects. Thus, our work characterized tumor-specific neutrophils in GC and revealed an essential role of YAP/TAZ-CD54 axis in tsNeus, opening a new possibility to develop neutrophil-based antitumor therapeutics.
Humans ; Animals ; Mice ; Adaptor Proteins, Signal Transducing/metabolism* ; Transcription Factors/metabolism* ; Stomach Neoplasms/pathology* ; Neutrophils/pathology* ; Signal Transduction/genetics* ; YAP-Signaling Proteins ; Tumor Microenvironment ; Hyaluronan Receptors/genetics*

Objective: To analyze the clinicopathological features and gene mutations of primary gastrointestinal stromal tumors (GISTs) of the stomach and intestine and the prognosis of intermediate- and high-risk GISTs. Methods: This was a retrospective cohort study. Data of patients with GISTs admitted to Tianjin Medical University Cancer Institute and Hospital from January 2011 to December 2019 were collected retrospectively. Patients with primary gastric or intestinal disease who had undergone endoscopic or surgical resection of the primary lesion and were confirmed pathologically as GIST were included. Patients treated with targeted therapy preoperatively were excluded. The above criteria were met by 1061 patients with primary GISTs, 794 of whom had gastric GISTs and 267 intestinal GISTs. Genetic testing had been performed in 360 of these patients since implementation of Sanger sequencing in our hospital in October 2014. Gene mutations in KIT exons 9, 11, 13, and 17 and PDGFRA exons 12 and 18 were detected by Sanger sequencing. The factors investigated in this study included: (1) clinicopathological data, such as sex, age, primary tumor location, maximum tumor diameter, histological type, mitotic index (/5 mm²), and risk classification; (2) gene mutation; (3) follow-up, survival, and postoperative treatment; and (4) prognostic factors of progression-free survival (PFS) and overall survival (OS) for intermediate- and high-risk GIST. Results: (1) Clinicopathological features: The median ages of patients with primary gastric and intestinal GIST were 61 (8-85) years and 60 (26-80) years, respectively; The median maximum tumor diameters were 4.0 (0.3-32.0) cm and 6.0 (0.3-35.0) cm, respectively; The median mitotic indexes were 3 (0-113)/5 mm² and 3 (0-50)/5 mm², respectively; The median Ki-67 proliferation indexes were 5% (1%-80%) and 5% (1%-50%), respectively. The rates of positivity for CD117, DOG-1, and CD34 were 99.7% (792/794), 99.9% (731/732), 95.6% (753/788), and 100.0% (267/267), 100.0% (238/238), 61.5% (163/265), respectively. There were higher proportions of male patients (χ²=6.390, P=0.011), tumors of maximum diameter > 5.0 cm (χ²=33.593, P<0.001), high-risk (χ²=94.957, P<0.001), and CD34-negativity (χ²=203.138, P<0.001) among patients with intestinal GISTs than among those with gastric GISTs. (2) Gene mutations: Gene mutations were investigated in 286/360 patients (79.4%) with primary gastric GISTs and 74/360 (20.6%) with primary intestinal GISTs. Among the 286 patients with gastric primary GISTs, 79.4% (227/286), 8.4% (24/286), and 12.2% (35/286), had KIT mutations, PDGFRA mutations, and wild-type, respectively. Among the 74 patients with primary intestinal GISTs, 85.1% (63/74) had KIT mutations and 14.9% (11/74) were wild-type. The PDGFRA mutation rate was lower in patients with intestinal GISTs than in those with gastric GISTs[ 0% vs. 8.4%(24/286), χ²=6.770, P=0.034], whereas KIT exon 9 mutations occurred more often in those with intestinal GISTs [22.2% (14/63) vs. 1.8% (4/227), P<0.001]. There were no significant differences between gastric and intestinal GISTs in the rates of KIT exon 11 mutation type and KIT exon 11 deletion mutation type (both P>0.05). (3) Follow-up, survival, and postoperative treatment: After excluding 228 patients with synchronous and metachronous other malignant tumors, the remaining 833 patients were followed up for 6-124 (median 53) months with a follow-up rate of 88.6% (738/833). None of the patients with very low or low-risk gastric (n=239) or intestinal GISTs (n=56) had received targeted therapy postoperatively. Among 179 patients with moderate-risk GISTs, postoperative targeted therapy had been administered to 88/155 with gastric and 11/24 with intestinal GISTs. Among 264 patients with high-risk GISTs, postoperative targeted therapy had been administered to 106/153 with gastric and 62/111 with intestinal GISTs. The 3-, 5-, and 10-year PFS of patients with gastric or intestinal GISTs were 96.5%, 93.8%, and 87.6% and 85.7%, 80.1% and 63.3%, respectively (P<0.001). The 3-, 5-, and 10-year OS were 99.2%, 98.8%, 97.5% and 94.8%, 92.1%, 85.0%, respectively (P<0.001). (4) Analysis of predictors of intermediate- and high-risk GISTs: The 5-year PFS of patients with gastric and intestinal GISTs were 89.5% and 73.2%, respectively (P<0.001); The 5-year OS were 97.9% and 89.3%, respectively (P<0.001). Multivariate analysis showed that high risk (HR=2.918, 95%CI: 1.076-7.911, P=0.035) and Ki-67 proliferation index > 5% (HR=2.778, 95%CI: 1.389-5.558, P=0.004) were independent risk factors for PFS in patients with intermediate- and high-risk GISTs (both P<0.05). Intestinal GISTs (HR=3.485, 95%CI: 1.407-8.634, P=0.007) and high risk (HR=3.753,95%CI:1.079-13.056, P=0.038) were independent risk factors for OS in patients with intermediate- and high-risk GISTs (both P<0.05). Postoperative targeted therapy was independent protective factor for PFS and OS (HR=0.103, 95%CI: 0.049-0.213, P<0.001; HR=0.210, 95%CI:0.078-0.564,P=0.002). Conclusions: Primary intestinal GIST behaves more aggressively than gastric GISTs and more frequently progress after surgery. Moreover, CD34 negativity and KIT exon 9 mutations occur more frequently in patients with intestinal GISTs than in those with gastric GISTs.
Male ; Humans ; Gastrointestinal Stromal Tumors/surgery* ; Retrospective Studies ; Ki-67 Antigen ; Stomach Neoplasms/pathology* ; Prognosis ; Mutation ; Intestines/pathology* ; Proto-Oncogene Proteins c-kit/genetics* ; Receptor, Platelet-Derived Growth Factor alpha/genetics*

Peritoneal metastasis of gastric cancer serving as the most frequent form of metastasis, is one of the leading causes of death. A portion of surgically treated patients often suffer from small peritoneal residual metastasis, which will lead to recurrence and metastasis of gastric cancer patients after surgery. Given these, the prevention and treatment of peritoneal metastasis of gastric cancer deserves more attention. Molecular residual disease (MRD) refers to the molecular abnormalities of tumor origin that cannot be found by traditional imaging or other laboratory methods after treatment, but can be found by liquid biopsy, representing the possibility of tumor persistence or clinical progress. In recent years, the detection of MRD based on ctDNA has gradually become a research hotspot in the prevention and treatment of peritoneal metastasis. Our team established a new method for MRD molecular diagnosis of gastric cancer, and reviewed the research achievements in this field.
Humans ; Stomach Neoplasms/pathology* ; Peritoneal Neoplasms/secondary* ; Liquid Biopsy ; Neoplasm, Residual/genetics*

OBJECTIVE: To investigate the expression of microRNA miR-431-5p in gastric cancer (GC) tissues and its effects on apoptosis and mitochondrial function in GC cells. METHODS: The expression level of miR-431-5p in 50 clinical samples of GC tissues and paired adjacent tissues was detected using real-time fluorescence quantitative PCR, and its correlation with the clinicopathological features of the patients was analyzed. A cultured human GC cell line (MKN-45 cells) were transfected with a miR-431-5p mimic or a negative control sequence, and the cell proliferation, apoptosis, mitochondrial number, mitochondrial potential, mitochondrial permeability transition pore (mPTP), reactive oxygen species (ROS) production and adenosine triphosphate (ATP) content were detected using CCK-8 assay, flow cytometry, fluorescent probe label, or ATP detection kit. The changes in the expression levels of the apoptotic proteins in the cells were detected with Western blotting. RESULTS: The expression level of miR-431-5p was significantly lower in GC tissues than in the adjacent tissues (P < 0.001) and was significantly correlated with tumor differentiation (P=0.0227), T stage (P=0.0184), N stage (P=0.0005), TNM stage (P=0.0414) and vascular invasion (P=0.0107). In MKN-45 cells, overexpression of miR-431-5p obviously inhibited cell proliferation and induced cell apoptosis, causing also mitochondrial function impairment as shown by reduced mitochondrial number, lowered mitochondrial potential, increased mPTP opening, increased ROS production and reduced ATP content. Overexpression of miR-431-5p significantly downregulated the expression of Bcl-2 and increased the expressions of pro-apoptotic proteins p53, Bcl-2 and cleaved caspase-3 protein. CONCLUSION The expression of miR-431-5p is down-regulated in GC, which results in mitochondrial function impairment and promotes cell apoptosis by activating the Bax/Bcl-2/caspase3 signaling pathway, suggesting the potential role of miR-431-5p in targeted therapy for GC.
Humans ; Apoptosis/genetics* ; bcl-2-Associated X Protein ; Caspase 3 ; Cell Line, Tumor ; Cell Proliferation/genetics* ; MicroRNAs/metabolism* ; Mitochondria/metabolism* ; Mitochondrial Permeability Transition Pore ; Reactive Oxygen Species ; Stomach Neoplasms/pathology*

OBJECTIVE: To investigate the expression of four-jointed box kinase 1 (FJX1) in gastric cancer (GC), its correlation with survival outcomes of the patients, and its role in GC progression. METHODS: The expression level of FJX1 in GC tissues and normal gastric mucosal tissues and its correlation with the survival outcomes of GC patients were analyzed using TCGA and GEO database GC cohort. Immunohistochemistry was used to detect FJX1 expression level in clinical specimens of GC tissue, and its correlations with the patients' clinicopathological parameters and prognosis were analyzed. Bioinformatic analysis was performed to identify the potential pathways of FJX1 in GC. The effects of FJX1 overexpression or FJX1 silencing on GC cell proliferation and expressions of proliferation-related proteins, PI3K, AKT, p-PI3K, and p-AKT were evaluated using CCK-8 assay and Western blotting. The effect of FJX1 overexpression on GC cell tumorigenicity was evaluated in nude mice. RESULTS: GC tissues showed significantly higher expressions of FJX1 mRNA and protein compared with normal gastric mucosa tissues (P < 0.05). The high expression of FJX1 was associated with poor prognosis of GC patients (P < 0.05) and served as an independent risk factor for poor survival outcomes in GC (P < 0.05). FJX1 was expressed mainly in the cytoplasm of GC cells in positive correlation with Ki67 expression (R=0.34, P < 0.05), and was correlated with CA199 levels, depth of tumor infiltration and lymph node metastasis of GC (P < 0.05). In the cell experiment, FJX1 level was shown to regulate the expressions of Ki67 and PCNA and GC cell proliferation (P < 0.05). Gene set enrichment analysis indicated that the PI3K/AKT pathway potentially mediated the effect of FJX1, which regulated the expressions of PI3K and AKT and their phosphorylated proteins. In nude mice, FJX1 overexpression in GC cells significantly promoted the growth of the transplanted tumors (P < 0.05). CONCLUSION FJX1 is highly expressed in GC tissues and is correlated with poor prognosis of GC patients. FJX1 overexpression promotes GC cell proliferation through the PI3K/AKT signaling pathway, and may serve as a potential prognostic biomarker and therapeutic target for GC.
Animals ; Mice ; Cell Proliferation ; Ki-67 Antigen ; Mice, Nude ; Phosphatidylinositol 3-Kinases ; Proto-Oncogene Proteins c-akt ; Signal Transduction ; Stomach Neoplasms/pathology* ; Humans ; Intercellular Signaling Peptides and Proteins/genetics*

Objective To clarify whether Helicobacter pylori (H. pylori) can promote metastasis of gastric cancer cells via the high-expression of induced B cell specific Moloney murine leukemia virus integration site 1 (Bmi-1). Methods The gastric cancer tissue specimens from 82 patients were collected for this study. The protein and gene expression level of Bmi-1 in gastric adenocarcinoma tissue were detected by immunohistochemistry and real time quantitative PCR, respectively. And meanwhile the correlation between Bmi-1 levels and pathological features, and prognosis of gastric cancer were analyzed retrospectively. Then, the GES-1 cells were transfected with pLPCX-Bmi-1 plasmid and infected with H. pylori respectively. After the Bmi-1 overexpression in GES-1 cells, the invasion ability of the GES-1 cells was detected by Transwell assay, and the cell cycle and apoptosis were detected by flow cytometry. Results The mRNA and protein of Bmi-1 expression in gastric cancer tissues were higher than tumor-adjacent tissue, and the high expression of Bmi-1 was positively correlated with tumor invasion, TNM stage, tumor differentiation, lymph node metastasis and H. pylori infection. When expression of Bmi-1 was up-regulated as a result of H.pylori infection or pLPCX-Bmi-1 transfection, the GES-1 cells had higher invasiveness and lower apoptosis rate with the above treatment respectively. Conclusion H. pylori infection can inhibit the apoptosis of gastric cancer cells and promote their invasion via up-regulating expression of Bmi-1.
Humans ; Cell Line, Tumor ; Helicobacter Infections/genetics* ; Helicobacter pylori ; Lymphatic Metastasis ; Retrospective Studies ; Stomach Neoplasms/pathology* ; Polycomb Repressive Complex 1/genetics*

Objective To investigate the effects of microRNA497 (miR-497) on the metastasis of gastric cancer and its possible molecular mechanism. Methods SGC-7901 gastric cancer parent cells were cultured in an ultra-low adhesion environment, and the anoikis resistance model of SGC-7901 cells was created after re-adhesion. Clone formation assay, flow cytometry, Transwell^TM test and scratch healing test were used to detect the differences of biological behavior compared with their parent cells. Fluorescence quantitative PCR was performed to detect the expression of miR-497. Western blot analysis was used to detect the changes of key proteins of Wnt/β-catenin signaling pathway and epithelial mesenchymal transformation (EMT) related proteins such as vimentin and E-cadherin. Parent cells and anoikis resistant SGC-7901 cells were transfected with miR-497 inhibitor or miR-497 mimic, and CCK-8 assay was used to detect the proliferation activity. Transwell^TM invasion assay was performed to detect the invasion ability of cells. Transwell^TM migration test and scratch healing assay was used to determine the migration ability. Western blot analysis was used to detect the expressions of Wnt1, β-catenin, vimentin and E-cadherin. By transfecting miR-497 mimic into the anoikis resistance SGC-7901 cells and inoculating them subcutaneously in nude mice, the changes in the volume and mass of tumor tissues were measured and recorded. Western blot analysis was used to determine the expressions of Wnt1, β-catenin, vimentin and E-cadherin of tumor tissues. Results Compared with the parent cells, the anoikis resistance SGC-7901 gastric cancer cells had faster proliferation rate, stronger colony formation, lower apoptosis rate, stronger invasion and migration ability. The expression of miR-497 was significantly decreased. After down-regulation of miR-497, the proliferation ability, invasion and migration ability were significantly enhanced. The expressions of Wnt1, β-catenin and vimentin increased significantly, while E-cadherin decreased notably. The results of up-regulation miR-497 were the opposite. The tumor growth rate, tumor volume and mass of miR-497 overexpression group were significantly lower than those of control group. The expressions of Wnt1, β-catenin and vimentin decreased significantly, while the expression of E-cadherin increased significantly. Conclusion The expression of miR-497 is low in the anoikis resistance SGC-7901 cells. miR-497 can inhibit the growth and metastasis of gastric cancer cells by blocking Wnt/β-catenin signaling pathway and EMT.
Animals ; Mice ; Humans ; beta Catenin/metabolism* ; MicroRNAs/metabolism* ; Vimentin/metabolism* ; Stomach Neoplasms/pathology* ; Anoikis/genetics* ; Wnt Signaling Pathway/genetics* ; Mice, Nude ; Cell Proliferation/genetics* ; Cadherins/genetics* ; Cell Line, Tumor ; Epithelial-Mesenchymal Transition/genetics* ; Cell Movement/genetics*

Objective: To investigate the role and mechanism of tumor-derived mesenchymal stem cells in regulating the M2 polarization of macrophages within gastric cancer microenvironment. Methods: Gastric cancer tissues and the adjacent non-cancerous tissues were collected from patients underwent gastric cancer resection in the First People's Hospital of Lianyungang during 2018. In our study, THP-1-differentiated macrophages were co-cultured with gastric cancer-derived mesenchymal stem cells (GC-MSCs). Then, the M2 subtype-related gene, the markers expressed on cell surface and the cytokine profile were analyzed by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), flow cytometry and Luminex liquid chip, respectively. The key cytokines mediating the inducing effect of GC-MSCs on macrophage polarization into the M2 subtype were detected and screened by Luminex liquid chip, which were further confirmed by the neutralizing antibody test. The expressions of macrophage proteins involved in M2 polarization-related signaling pathways under the different co-culture conditions of GC-MSCs were detected by western blot. Results: In Mac+ GC-MSC-culture medium (CM) group, the expression levels of Ym-1 and Fizz-1 (1.53±0.32 and 13.22±1.05, respectively), which are markers for M2 subtype, were both significantly higher than those of Mac group (1.00±0.05 and 1.21±0.38, respectively, P<0.05). The level of iNOS in Mac+ GC-MSC-CM group (0.60±0.41) was significantly lower than that of Mac group (1.06±0.38, P=0.023). In Mac+ GC-MSC-Transwell (TW) group, the expression levels of Ym-1 and Fizz-1 (1.47±0.09 and 13.16±2.77, respectively) were both significantly higher than those of Mac group (1.00±0.05 and 1.21±0.38, respectively, P<0.05). The level of iNOS in Mac+ GC-MSC-CM group (0.56±0.03) was significantly lower than that of Mac group (1.06±0.38, P=0.026). The ratios of CD163(+) /CD204(+) cells in Mac+ GC-MSC-CM and Mac+ GC-MSC-TW groups (3.80% and 4.40%, respectively) were both remarkably higher than that of Mac group (0.60%, P<0.05). The expression levels of IL-10, IL-6, MCP-1 and VEGF in Mac+ GC-MSC-CM group were (592.60±87.52), (1 346.80±64.70), (11 256.00±29.03) and (1 463.90±66.67) pg/ml, respectively, which were significantly higher than those of Mac group [(41.03±2.59), (17.35±1.79), (5 213.30±523.71) and (267.12±12.06) pg/ml, respectively, P<0.05]. The levels of TNF-α, IP-10, RANTES and MIP-1α were (95.57±9.34), (410.48±40.68), (6 967.30±1.29) and (1 538.70±283.04) pg/ml, which were significantly lower than those of Mac group [(138.01±24.31, (1 298.60±310.50), (14 631.00±4.21) and (6 633.20±1.47) pg/ml, respectively, P<0.05]. The levels of IL-6 and IL-8 in GC-MSCs [(11 185.02±2.82) and (12 718.03±370.17) pg/ml, respectively] were both strikingly higher than those of MSCs from adjacent non-cancerous gastric cancer tissues [(270.71±59.38) and (106.04±32.84) pg/ml, repectively, P<0.05]. The ratios of CD86(+) cells in Mac+ IL-6-blocked-GC-MSC-CM and Mac+ IL-8-blocked-GC-MSC-CM groups (28.80% and 31.40%, respectively) were both higher than that of Mac+ GC-MSC-CM group (24.70%). Compared to Mac+ GC-MSC-CM group (13.70%), the ratios of CD204(+) cells in Mac+ IL-6-blocked-GC-MSC-CM and Mac+ IL-8-blocked-GC-MSC-CM groups (9.90% and 8.70%, separately) were reduced. The expression levels of p-JAK2 and p-STAT3, which are proteins of macrophage M2 polarization-related signaling pathway, in Mac+ GC-MSC-CM group (0.86±0.01 and 1.08±0.01, respectively) were significantly higher than those of Mac group (0.50±0.01 and 0.82±0.01, respectively, P<0.05). The expression levels of p-JAK2 in Mac+ IL-6-blocked-GC-MSC-CM group (0.47±0.02) were significantly lower those that of Mac+ GC-MSC-CM group (0.86±0.01, P<0.05). The expression levels of p-JAK2 and p-STAT3 in Mac+ IL-8-blocked-GC-MSC-CM group (0.50±0.01 and 0.85±0.01, respectively) were both significantly lower than those of Mac+ GC-MSC-CM group (0.86±0.01 and 1.08±0.01, P<0.05). The expression levels of p-JAK2 and p-STAT3 in Mac+ IL-6/IL-8-blocked-GC-MSC-CM group (0.37±0.01 and 0.65±0.01, respectively) were both significantly lower than those of Mac+ GC-MSC-CM group (0.86±0.01 and 1.08±0.01, P<0.05). Conclusion: GC-MSCs promote the activation of JAK2/STAT3 signaling pathway in macrophages via high secretions of IL-6 and IL-8, which subsequently induce the macrophage polarization into a pro-tumor M2 subtype within gastric cancer microenvironment.
Humans ; Interleukin-6/genetics* ; Interleukin-8/pharmacology* ; Janus Kinase 2/metabolism* ; Macrophages/metabolism* ; Mesenchymal Stem Cells ; STAT3 Transcription Factor/metabolism* ; Signal Transduction ; Stomach Neoplasms/pathology* ; Tumor Microenvironment

Objective: To investigate the relationship between the expression of integrin α 6 (ITGA6), miR-4484 and the pathologic stage of gastric cancer. Methods: Gastric cancer tissues and normal gastric mucosa tissues adjacent to cancer (>5 cm from tumor margin) of 30 patients with primary gastric cancer who underwent direct surgical resection without adjuvant therapy from June to September 2017 in West China Hospital of Sichuan University were selected. Real-time quantitative polymerase chain reaction (PCR) was used to detect the expression levels of miR-4484 and ITGA6, western blot was used to detect the expression level of ITGA6 protein, dual luciferase reporter gene was used to verify the relationship between ITGA6 and miR-4484. Spearman's correlation analysis was used to determine the relationship between miR-4484 and ITGA6 expression levels in gastric cancer tissues. Results: The expression level of ITGΑ6 in gastric cancer (32.30±13.47) was higher than that in matched normal gastric tissues (24.55±10.25, P=0.015), the area under the receiver operating characteristic (ROC) curve was 0.660 and the diagnostic sensitivity and specificity were 43.3% and 96.7%, respectively. The expression level of miR-4484 in gastric cancer (4.11±2.87) was lower than that of matched normal gastric tissues (5.75±2.80, P=0.029), the area under the ROC curve was 0.690 and the diagnostic sensitivity and specificity were 30.0% and 86.7%, respectively. The expression level of miR-4484 was negatively correlated with ITGA6 in gastric cancer tissues (r=-0.621, P<0.001). The expression level of ITGA6 protein in gastric cancer tissues (0.65±0.19) was higher than that in normal adjacent tissues (0.26±0.12, P<0.001). Compared with ITGA6 3'UTR wild-type+ miR-NC group, ITGA6 3'UTR wild-type+ miRNA mimics group had lower luciferase activity (50.69±5.10, 34.00±1.19, P<0.001), while the luciferase activity of ITGA6 3'UTR wild-type+ ASO miR-4484 group was higher than that of ITGA6 3'UTR wild-type+ miR-NC group (82.44±6.37, 50.69±5.10, P<0.001), indicated that ITGA6 was the direct target gene of miR-4484. The expression levels of miR-4484 in T1, T2, T3 and T4 (4a and 4b) gastric cancer tissues were 9.98±2.24, 5.28±2.03, 2.92±2.04 and 4.11±2.87, respectively, with statistical significance (P<0.001). The expression levels of ITGA6 in N0, N1, N2 and N3 gastric cancer tissues were 29.55±8.32, 21.71±3.75, 24.60±8.79 and 40.69±15.83, respectively, with statistical significance (P=0.022). The expression levels of miR-4484 in N0, N1, N2 and N3 gastric cancer tissues were 5.01±3.52, 5.48±2.76, 5.88±1.83 and 2.30±1.56, respectively, with statistical significance (P=0.032). The expression levels of ITGA6 in M0 and M1 gastric cancer tissues were 26.28±7.66 and 52.08±8.12, respectively, with statistical significance (P<0.001). The expression levels of miR-4484 in M0 and M1 gastric cancer tissues were 4.95±2.74 and 1.34±0.80, respectively, with statistical significance (P<0.001). Conclusions: ITGA6 is upregulated in gastric cancer tissues, while miR-4484 is downregulated in the gastric cancer group, and its expression level is related to the clinicopathological features of gastric cancer. ITGA6 is the direct target gene of miR-4484, implicates that miR-4484 may inhibit the invasion and metastasis of gastric cancer by regulating the expression of ITGA6. Both miR-4484 and ITGA6 may be the new prognostic markers and potential therapeutic targets of gastric cancer.
3' Untranslated Regions ; China ; Humans ; Integrin alpha6/genetics* ; MicroRNAs/genetics* ; Stomach Neoplasms/pathology*