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Objective:To explore the expression of long-chain noncoding RNA (lncRNA) and myocardial infarction-associated transcription (MIAT) in Leukocyte differentiation antigen (CD)4+T cells in peripheral blood of gastric cancer patients and its value of clinical application.Methods:Peripheral blood CD4+T cells were collected from 124 patients with gastric cancer, 90 benign gastric diseases patients and 80 healthy controls enrolled in Taizhou People′s Hospital from January 2019 to April 2021. The expression levels of MIAT and N6-methyladenosine(m6A) binding to MIAT promoter in CD4+T cells were detected by real-time fluorescent quantitative polymerase chain reaction (qPCR) and Chromatin immunoprecipitation (ChIP)-qPCR, respectively. Spearman test was used to analyze the correlation between MIAT and clinicopathological features, as well as between MIAT and regulatory T cell levels. The receivor operating characteristic curve (ROC) of the subjects was used to evaluate the MIAT expression level in the auxiliary diagnostic value of gastric cancer.Results:The relative expression levels of MIAT in the gastric cancer patients, the benign gastric diseases patients, and the healthy controls were 2.849 (2.131, 4.062), 1.511 (0.916, 1.855) and 0.963 (0.729, 1.432), respectively. The difference among the three groups was statistically significant ( H=158.25, P<0.001). The relative expression level of MIAT in the gastric cancer patients was significantly higher than the levels in the benign gastric diseases patients and healthy controls. The difference was statistically significant ( Z=100.63, 145.14, P<0.001). The binding activity of m6A to MIAT promoter in patients with early stage (stage Ⅰ and Ⅱ) and end stage (stage Ⅲ and Ⅳ) gastric cancer was 8.590±1.483 and 4.274±0.425, respectively. The difference was statistically significant ( t=6.255, P=0.002). Furthermore, the binding activity of m6A to MIAT promoter in the gastric cancer patients was significantly lower than that in patients with benign gastric diseases (17.267±3.106) and healthy controls (27.637±3.945) ( t=-7.331,-12.832, P<0.001). The relative expression of MIAT in CD4+T cells in peripheral blood of the gastric cancer patients had no significant difference in age(χ2=0.000, P=1.000), gender(χ2=0.000, P=1.000), CEA (χ2=0.648, P=0.421) and CA199(χ2=1.554, P=0.213), but had significant difference with tumor size expression(χ2=9.443, P<0.01), TNM stage(χ2=23.571, P=0.002) and lymph node metastasis (χ2=45.248, P<0.01). In addition, there was a significant positive correlation between the relative expression of MIAT in CD4+T cells and Treg level ( r2=0.76, P<0.001). The diagnostic efficacies of MIAT in CD4+T cells, CEA and CA199 in the gastric cancer patients were analyzed by ROC curve. When compared with patients with benign gastric diseases, the areas under the curve were 0.879, 0.635 and 0.611, respectively. When compared with healthy patients, the areas under the curve were 0.953, 0.784 and 0.598, respectively. Conclusions:The level of MIAT in CD4+T cells in peripheral blood of patients with gastric cancer is significantly higher than the levels in patients with benign gastric diseases and the healthy controls, which may be related with the decreased activity of m6A binding to the promoter of MIAT. The level of MIAT in CD4+T cells may be a relevant biomarker for the diagnosis and prognosis of gastric cancer.
RESUMO
Non-small-cell lung cancer (NSCLC) is a complex disease which is influenced by multiple factors. Recentstudies demonstrated that long non-coding RNA (lncRNA) MIAT was involved in tumor metastasis. However,the underlying mechanism of MIAT in NSCLC remains largely unknown. In this study, MIAT, miR-139-5pand MMP2 expression were measured by quantitative reverse transcriptase PCR (QRT-PCR) or Westernblotting, respectively, and we found the expression of MIAT and MMP2 were elevated, while miR-139-5p wasdecreased in NSCLC tissues and cell lines. Transwell assay showed MIAT and MMP2 functioned as anoncogene to induce cell migration and invasion in NSCLC, but miR-139-5p served as a tumor suppressor inNSCLC to inhibit cell migration and invasion. Besides that, in vivo experiments also indicated MIAT deletioninhibited tumor growth. The relationship between miR-139-5p and MIAT or MMP2 was then confirmed byLuciferase reporter assay, and the results showed that MIAT directly interacted with miR-139-5p and miR-139-5p targetedly suppressed MMP2 in NSCLC cells. Furthermore, expression analysis showed that MIAT indirectly regulated MMP2 by sponging miR-139-5p. Finally, rescue assay suggested that miR-139-5p restorationreversed MIAT-overexpression-induced promotion on the migration and invasion of NSCLC cells. In conclusion, our results demonstrated that lncRNA MIAT modulated the migration and invasion of NSCLC byregulating miR-139-5p and MMP2.