RESUMO
miR-340 can promote the proliferation and invasion of cancer cells, but how miR-340 regulates the occurrence and development of cancer in colon cancer is rarely reported. This study aims to explore the biological function and target gene regulation mechanism of miR-340 in colorectal cancer cells. Firstly, RT-qPCR was used to detect the expression level of miR-340 in different colorectal cancer cell lines, and then miR-340 was overexpressed or inhibited in COLO-205 cells. CCK-8, Transwell migration and invasion assay, and flow cytometry were performed to analyze the cell ability of proliferation, migration and invasion, as well as cell apoptosis and cell cycle. Finally, after bioinformatics prediction of miR-340 target genes, luciferase reporter gene and Western blot experiment were applied to verify those target genes. The results showed that miR-340 was downregulated in COLO-205 cells. Compared with the control group, cell proliferation, migration and invasion were significantly inhibited in the miR-340 overexpression group, but were promoted in the miR-340 suppression group (P<0. 01). The results of flow cytometry showed that the percentage of apoptosis in the miR-340 overexpression group was significantly increased, while the percentage of apoptosis in the miR-340 inhibition group was decreased (P<0. 01). The bioinformatics analysis of the overexpression miR-340 transfection group showed that the 3′UTR of glucose regulated protein 78 kD (GRP78) had a miR-340-5p binding site, and the luciferase activity was significantly reduced in the overexpression miR-340 group (P<0. 01); Western blot results also showed that overexpression of miR-340 can inhibit the expression of GRP78, while inhibiting miR-340 expression, the expression of GRP78 is relieved. In summary, miR-340 can directly target GRP78 to promote the apoptosis of COLO-205 cells and inhibit their proliferation, migration and invasion.
RESUMO
<p><b>BACKGROUND</b>Hydrothorax, as one of the common complications of malignant tumors, still cannot be sensitively detected in clinical practice, thus requiring a sensitive, specific method for diagnosis. The aim of this study was to analyze the correlation between levels of vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) in patients with benign and malignant hydrothorax.</p><p><b>METHODS</b>The contents of VEGF in the pleural effusion and serum of the patients with malignant pleural effusion (n = 35) and benign pleural effusion (n = 30) were detected by double antibody sandwich enzyme linked immunosorbent assay. The gene copy number level of EGFR in pleural effusion was detected by fluorescence in situ hybridization (FISH). The points with the highest sensitivity and specificity were selected as the critical values to calculate the diagnostic value of the VEGF in pleural effusion and serum, and EGFR gene copy number in pleural effusion.</p><p><b>RESULTS</b>The contents of VEGF in pleural effusion and serum of patients with malignant hydrothorax were (384.91 ± 120.18), and (129.62 ± 46.35) ng/L, respectively, which were significantly higher than those of the patients with benign hydrothorax (207.97 ± 64.04), (63.49 ± 24.58) ng/L (P < 0.01). The sensitivity and specificity of detecting VEGF in pleural effusion were 80.0% and 96.7% (the boundary value was 297.06 ng/L), respectively for diagnosing benign and malignant hydrothorax. The sensitivity and specificity of serum were 74.3% and 96.7%, respectively (the boundary value was 99.21 ng/L) for diagnosing benign and malignant hydrothorax. The diagnostic efficiencies of EGFR and VEGF in hydrothorax were similar. There was a significant correlation between EGFR and VEGF in hydrothorax (P < 0.01).</p><p><b>CONCLUSIONS</b>VEGF and EGFR play important roles in the formation of pleural effusion. VEGF differed significantly in benign and malignant pleural effusions, which contributed to differential diagnosis results of benign and malignant pleural effusions. It is feasible to detect the gene copy number of the pleural effusion cell mass EGFR by FISH technique. Joint detection can improve the diagnostic sensitivity.</p>