Relationship between miR-21 and miR-182 levels in peripheral blood and gastric cancer tissue

Abstract

The relationship between miR-21 and miR-182 gene expression in peripheral blood and gastric cancer tissue was investigated, exploring the relationship between the levels of miR-21 and miR-182 and prognosis of gastric cancer patients, and determining the effects of these two genes on the growth and migration of gastric cancer cells. Fifty gastric cancer patients who were treated in the 254th Hospital of PLA, from July 2012 to July 2014 were selected. Peripheral blood samples were drawn from patients, and 50 healthy subjects were studied as controls. The levels of the miR-21 and miR-182 genes were detected by semi-quantitative PCR, and the correlation between miR-21 and miR-182 expression and clinicopathological features was explored. Moreover, the effects of miR-21 and miR-182 expression on the survival time and prognosis of patients were investigated. siRNA was used to downregulate miR-21 and miR-182 gene expression in MGC-803 gastric cancer cells, and MTT and Transwell assays were conducted. As a result, the relative expression levels of miR-21 and miR-182 in peripheral blood of gastric cancer patients were significantly higher than in healthy subjects (p<0.01) and the relative expression of miR-182 was closely related to the clinicopathological features of gastric cancer patients (p<0.05); high expression of miR-21 and miR-182 was associated with reduced survival time of patients (p<0.05); MGC-803 cells with low expression of miR-21 and miR-182 were analyzed, showing that miR-182 promoted cell proliferation and migration (p<0.01). In conclusion, the relative levels of miR-21 and miR-182 in peripheral blood of patients with gastric cancer are significantly increased; low expression of miR-182 can significantly reduce the proliferation and migration of gastric cancer cells. Moreover, miR-182 expression, which is closely related to the clinicopathological features of gastric cancer, can serve as a target for the clinical treatment of gastric cancer.

Keywords: gastric cancer; miR-182; miR-21; peripheral blood.

Figure 1.

The levels of miR-21 and miR-182 in gastric cancer patients and healthy subjects as detected by semi-quantitative PCR. (A) Agarose gel electrophoretogram. (B and C) Statistical analysis of the relative levels of miR-21 and miR-182, respectively; the relative expression of miR-21 and miR-182 was significantly higher in peripheral blood of gastric cancer patients than in healthy subjects (**p<0.01).

Figure 2.

Relationship between miR-21 expression and survival time of patients; the survival time of patients in the miR-21 high expression group was significantly shorter than that of patients in the miR-21 normal expression or low expression group (p<0.01).

Figure 3.

Relationship between miR-182 expression and survival time of patients; the survival time of patients in the miR-182 high expression group was significantly lower than that of patients in the miR-182 normal or low expression group (p<0.01).

Figure 4.

(A) The establishment of MGC-803 cells with low expression of miR-21; the expression of miR-21 in cells of the miR21-siRNA group was significantly lower than that of the siRNA-control group; (B) the establishment of MGC-803 cells with low expression of miR-182; the expression of miR-182 in cells of the miR182-siRNA group was significantly lower than that of the siRNA-control group.

Figure 5.

Analysis of cell proliferation by MTT assay; (A) the effect of low expression of miR-21 on cell proliferation; compared with the siRNA-control group, there was no obvious change in the quantity of cells in the miR21-siRNA group (p>0.05); (B) the effect of low expression of miR-182 on cell proliferation; compared with the siRNA-control group, the quantity of cells in the miR182-siRNA group was significantly decreased (**p<0.01).

Figure 6.

Analysis of migration ability of cells by Transwell assay; (A) successfully transfected MGC-803 cells with low expression of miR-21 under microscopy (bar, 50 µm); (B) column statistical graph; compared with the siRNA-control group, there was no evident change in migration ability of cells in the miR21-siRNA group (p>0.05); (C) the successfully transfected MGC-803 cells with low expression of miR-182 under microscopy (bar, 50 µm); (D) column statistical graph; compared with the siRNA-control group, the migration ability of cells in the miR182-siRNA group was significantly decreased (**p<0.01).