Comprehensive analysis of peroxisome proliferator-activated receptors to predict the drug resistance, immune microenvironment, and prognosis in stomach adenocarcinomas.

Background: Peroxisome proliferator-activated receptors (PPARs) exert multiple functions in the initiation and progression of stomach adenocarcinomas (STAD). This study analyzed the relationship between PPARs and the immune status, molecular mutations, and drug therapy in STAD. Methods: The expression profiles of three PPAR genes (PPARA, PPARD and PPARG) were downloaded from The Cancer Genome Atlas (TCGA) dataset to analyze their expression patterns across pan-cancer. The associations between PPARs and clinicopathologic features, prognosis, tumor microenvironment, genome mutation and drug sensitivity were also explored. Co-expression between two PPAR genes was calculated using Pearson analysis. Regulatory pathways of PPARs were scored using gene set variation analysis (GSVA) package. Quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, Cell Counting Kit-8 (CCK-8) assay and transwell assay were conducted to analyze the expression and function of the PPAR genes in STAD cell lines (AGS and SGC7901 cells). Results: PPARA, PPARD and PPARG were more abnormally expressed in STAD samples and cell lines when compared to most of 32 type cancers in TCGA. In STAD, the expression of PPARD was higher in Grade 3+4 and male patients, while that of PPARG was higher in patient with Grade 3+4 and age > 60. Patients in high-PPARA expression group tended to have longer survival time. Co-expression analysis revealed 6 genes significantly correlated with the three PPAR genes in STAD. Single-sample GSEA (ssGSEA) showed that the three PPAR genes were enriched in 23 pathways, including MITOTIC_SPINDLE, MYC_TARGETS_V1, E2F_TARGETS and were closely correlated with immune cells, including NK_cells_resting, T_cells_CD4_memory_resting, and macrophages_M0. Immune checkpoint genes (CD274, SIGLEC15) were abnormally expressed between high-PPAR expression and low-PPAR expression groups. TTN, MUC16, FAT2 and ANK3 genes had a high mutation frequency in both high-PPARA/PPARG and low-PPARA/PPARG expression group. Fourteen and two PPARA/PPARD drugs were identified to be able to effectively treat patients in high-PPARA/PPARG and low-PPARA/PPARG expression groups, respectively. We also found that the chemotherapy drug Vinorelbine was positively correlated with the three PPAR genes, showing the potential of Vinorelbine to serve as a treatment drug for STAD. Furthermore, cell experiments demonstrated that PPARG had higher expression in AGS and SGC7901 cells, and that inhibiting PPARG suppressed the viability, migration and invasion of AGS and SGC7901 cells. Conclusions: The current results confirmed that the three PPAR genes (PPARA, PPARD and PPARG) affected STAD development through mediating immune microenvironment and genome mutation.

MiR-30c-5p suppresses migration, invasion and epithelial to mesenchymal transition of gastric cancer via targeting MTA1.

BACKGROUND: In China, gastric cancer (GC) is an ordinary malignant tumor. Recent literatures have shown that microRNA is critical during tumorigenesis. This study focuses on the influence of miR-30c-5p on the metastasis of GC and further explores its underlying mechanism. METHODS: Before the study, expression level of miR-30c-5p and targeted protein was detected in 40 GC tissue samples and 5 GC cells by RT-qPCR. Meanwhile, correlation analysis was conducted between miR-30c-5p expression level and clinicopathological features. In addition, wound healing assay and cell invasion assay were utilized to identify whether miR-30c-5p could affect the migrated and invaded ability of GC cells. Western blotting assay and luciferase assay were used to explore the potential mechanism. RESULTS: In GC tissues, miR-30c-5p expression level was significantly lower and was remarkably related with clinical features such as tumor node metastasis(TNM) stage and lymphatic metastasis. Moreover, the migrated and invaded ability of GC cells was enhanced through knockdown of miR-30c-5p, while overexpression of miR-30c-5p presented with reversed effect. Further study showed that miR-30c-5p inhibited the expression of its target spot, metastasis-associated protein 1(MTA1), and then suppressed the process of epithelial to mesenchymal transition(EMT) which was important in the metastasis of GC. CONCLUSION: The results indicate that miR-30c-5p, a novel suppressor in tumorigenesis, could inhibit the metastasis and EMT via MTA1, which may offer a possible therapeutic target in GC.

miRNA-148b regulates radioresistance in non-small lung cancer cells via regulation of MutL homologue 1.

Radioresistance represents a major obstacle in cancer treatment, the underlying mechanism of which is complex and not well understood. miR-148b has been reported to be implicated regulating radioresistance in lymphoma cells. However, this function has not been investigated in lung cancer cells. Microarray analysis was performed in A549 cells 48 h after exposure to 8 Gy of γ-irradiation or sham irradiation to identify differentially expressed miRNAs. miR-148b mimic and inhibitor were transfected, followed by clonogenic survival assay to examine response to irradiation in A549 cells. Western Blot and luciferase assay were performed to investigate the direct target of miR-148b Xenograft mouse models were used to examine in vivo function of miR-148b Our data showed that expression of miR-148b was significantly down-regulated in both serum and cancerous tissues of radioresistant lung cancer patients compared with radiosensitive patients. Overexpression of miR-148b reversed radioresistance in A549 cells. MutL homologue 1 (MLH1) is the direct target of miR-148b which is required for the regulatory role of miR-148b in radioresistance. miR-148b mimic sensitized A549 xenografts to irradiation in vivo Our study demonstrated that miR-148b regulates radioresistance of lung cancer cells by modulating MLH1 expression level. miR-148b may represent a new therapeutic target for the intervention of lung cancer.

Clinicopathological significance of E-cadherin, VEGF, and MMPs in gastric cancer.

E-cadherin, vascular endothelial growth factor (VEGF), and matrix metalloproteinases (MMPs) are important molecules involved in tumor metastasis. In this study, we examined the expressions of E-cadherin, VEGF, MMP-1, MMP-2, and microvessel density (MVD), as well as microlymphatic vessel density (MLVD) in 200 cases of gastric cancer tissues, and determined the relationship between these parameters and the clinicopathological features and patient survival. Protein expressions, MVD, and MLVD were detected by immunohistochemistry. The correlation between the expression levels of these molecules and the clinicopathological features was analyzed. Patient survival was estimated by Kaplan and Meier analysis. Compared to normal gastric mucosa, expression of E-cadherin was reduced in 78% of gastric cancer tissues and 44.6% of adjacent non-cancerous gastric tissues. VEGF was positive in 81.5% of gastric cancer tissues, 35.7% of adjacent non-cancerous gastric tissues, and 10% of normal gastric mucosa. MMP-1 was positive in 80.5% of gastric cancer tissues, 69.6% of adjacent non-cancerous gastric tissues, and 20% of normal gastric mucosa. Reduced expression of E-cadherin was closely correlated with poor tumor differentiation and a deeper tumor invasion. Increased expressions of VEGF and MMP-1 were closely linked with poor differentiation and Lauren classification. Increased expression of MMP-2 was closely correlated with more lymph node metastasis, a deeper invasion, and a larger tumor size. More MVD was observed in VEGF-positive tissues than in VEGF negative tissues. Therefore, abnormal expressions of E-cadherin, VEGF, MMP-1, and MMP-2 are widely present in gastric cancer tissues. Abnormal expressions of E-cadherin, VEGF, and MMP-2 may represent the early molecular changes in the development of gastric cancer. Positive expression of E-cadherin and negative expression of VEGF and MMP-2 are correlated with a better patient survival.

[Epidemiological study on status of Helicobacter pylori in children and teenagers in Wuwei city, Gansu province].

OBJECTIVE: To investigate the prevalence of Helicobacter pylori (Hp) infection among children aged 3 to 18 years old of Wuwei city, Gansu province. METHODS: The study was based upon a personal questionnaire and a determination of Hp antigen using the Hp stool antigen test (HpSA) method. A total of 938 subjects and 96 families were selected in Wuwei city. Eighty children and teenagers with a definite positive Hp stool antigen test were examined by serum Western blotting method. RESULTS: The prevalence of Hp was 72.3% (678/938) with no age difference. Prevalence of Hp infection was correlated with type of dwelling, occupation of parents, drinking water source, kindergarten attendance, consumption of raw vegetables, a poor oral hygiene and breast feeding etc. According to the multivariate analysis, drinking water source, kindergarten attendance and consumption of raw vegetables were most strongly associated with prevalence of Hp in children and adolescents. The infection rate of parents whose children were infected with Hp was higher than that of those whose children were not infected [82.3% (121/147) vs 47.4% (18/38), chi(2) = 19.736, P < 0.05]. The antibody responses of 57 samples (71.3%) from 80 children were of type I Hp and 23 samples (28.7%) type II. CONCLUSIONS: Hp infective rate is high in Wuwei city. The data support maternal-child and sibling-sibling transmission as the primary transmission routes of Hp. The results of serological analysis confirm that the majority of Wuwei Hp infection is of type I.

[Expression of cyclooxygenase-2 and urokinase plasminogen activator in gastric carcinoma and the clinical significance thereof].

OBJECTIVE: To investigate expression of cyclooxygenase-2 (COX-2) and urokinase plasminogen activator (uPA) in gastric carcinoma and the clinical significance thereof. METHODS: Strepavidin-peroxidase method was used to detect the expression of COX-2 and uPA in 192 specimens of gastric carcinoma, 56 specimens of paracancer tissues obtained during operation. Immunohistochemical double staining was used to detect the microvessel density (MVD) and microlymphatic density (MLD). Thirty specimens of normal gastric mucosa obtained during gastroscopy were used as controls. RESULTS: The positive rates of COX-2 in the gastric carcinoma and paracancer tissues were 67.7% and 62.5% respectively, both significantly higher than that of the control group (40.0%, both P < 0.05). The positive expression of COX-2 in gastric carcinoma was significantly related with the depth of invasion and MVD (both P < 0.05). The positive rates of uPA in the gastric carcinoma, paracancer tissue were 78.1% and 44.6% respectively, both significantly higher than that of the control tissues (6.7%, both P < 0.01) and there was a significant difference in the positive rates of uPA between the first 2 groups too (P < 0.01). The positive expression of uPA in gastric carcinoma was significantly related with lymph node metastasis, depth of invasion, Lauren typing, differentiation, MVD, and MLD (P < 0.05, P < 0.01). COX-2 expression was positively linked with uPA expression (r = 0.167, P = 0.021). The survival time of the uPA positive group was (38 +/- 4) months, significantly shorter than that of the negative group [(54 +/- 6) months, P < 0.05]. The survival time of the group positive in both COX-2 and uPA was (27 +/- 3) months, significantly shorter than that of the single positive or double negative groups [both (58 +/- 4) months, both P < 0.01). CONCLUSION: COX-2 and uPA are highly expressed in gastric carcinoma. COX-2 expression is positively linked with uPA expression. COX-2 and uPA in the gastric carcinoma participate in the development of gastric cancer in the early process. uPA is significantly related with the survival time.