Hypoxia-inducible factor 1α affects the migration and invasion of hypoxia-inducible pancreatic cancer cells through regulating miRNA-296-5p / 肿瘤研究与临床

ABSTRACT

Objective:To investigate the effect of miRNA-296-5p (miR-296-5p) on the migration and invasion of hypoxia-induced pancreatic cancer cells and its related mechanisms.Methods:Human pancreatic cancer cell line PANC-1 was selected. Pancreatic cancer tissues from 55 pancreatic cancer patients who underwent the resection and adjacent carcinoma normal pancreatic tissues from 10 patients at Shanghai Fengxian District Central Hospital and Bengbu Medical College First Affiliated Hospital between January 2010 and December 2014 were collected. The expression levels of hypoxia-inducible factor 1α (HIF-1α) and miR-296-5p in tissue microarray of pancreatic cancer and adjacent carcinoma normal pancreatic tissues were detected by using immunohistochemistry and in situ hybridization. The relationship between miR-296-5p and HIF-1α as well as their correlation with clinicopathological characteristics of patients were analyzed. PANC-1 cells were divided into hypoxic group and normoxic group. Transwell assay was used to detect the cell migration and invasion ability of both groups. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to examine the expressions of HIF-1α and miR-296-5p under hypoxic environment of both groups. The expression of HIF-1α was interfered by transfecting small interfering RNA (siRNA). PANC-1 cells were divided into PANC-1 group (the empty control), PANC-1-NC group (the negative control) and PANC-1-siRNA group. The expression of miR-296-5p was measured. After co-transfecting miR-296-5p agonist and miR-296-5p inhibitor, the cells were divided into Agomir-miR-296-5p group (agonist group), Agomir-miR-296-5p-NC group (agonist negative control group), Antagomir-miR-296-5p group (inhibitor group) and Antagomir-miR-296-5p-NC group (inhibitor negative control group). Transwell assay was used to detect the cell migration and invasion ability of all groups. Luciferase reporter gene system was used to verify whether miR-296-5p promoter region had binding site of HIF-1α.Results:The high expression rate of HIF-1α in pancreatic cancer tissues was higher than that of adjacent carcinoma normal pancreatic tissues [81.8% (45/55) vs. 0 (0/10), P<0.01], and the high expression rate of miR-296-5p in pancreatic cancer tissues was lower than that of adjacent carcinoma normal pancreatic tissues [12.7% (7/55) vs. 90.0% (9/10), χ2 = 27.23, P<0.01]. The expression of HIF-1α was negatively correlated with that of miR-296-5p ( r = -0.53, P<0.01). The low expression of miR-296-5p was closely related with the tumor diameter, TNM staging, lymph node metastasis (all P<0.05). The number of PANC-1 invasion cell was 15.3±2.1 in normoxic group and 24.7±1.5 in hypoxic group, and the difference was statistically significant ( t = 0.26, P = 0.003). The number of PANC-1 migration cell was 20.7±3.8 in hypoxic group and 32.7±1.2 in normoxic group, and the difference was statistically significant ( t = 5.25, P = 0.006). The relative expression level of HIF-1α mRNA in PANC-1 cell of hypoxic group was higher than that of normoxic group [(1.00±0.01) vs. (0.30±0.02)], and the difference was statistically significant ( t = 56.45, P<0.01); the relative expression level of miR-296-5p in PANC-1 cell of hypoxic group was lower than that of normoxic group [(1.14±0.04) vs. (3.05±0.20)], and the difference was statistically significant ( t = 16.05, P<0.01). The number of invasion cells in PANC-1 group, PANC-1-NC group and PANC-1-siRNA group was 24.7±1.5, 25.7±1.5, 12.0±1.7, respectively, and the difference was statistically significant ( F = 68.13, P<0.01).The cell invasion ability in PANC-1-siRNA group was decreased compared with that in PANC-1 group ( t = 9.50, P = 0.001). The number of cell migration was 32.7±1.2, 37±1.0, 17.3±1.2, respectively in PANC-1 group, PANC-1-NC group and PANC-1-siRNA group, and the difference was statistically significant ( F = 262.09, P<0.01). The cell migration ability in PANC-1-siRNA group was decreased compared with that in PANC-1 group ( t = 16.26, P<0.01). The cell invasion and migration ability in Antagomir-miR-296-5p group was increased compared with that in PANC-1 group (all P<0.05); the cell invasion and migration ability in Agomir-miR-296-5p group was decreased compared with that in PANC-1 group (all P<0.05). The results of luciferase activity detected by luciferase reporter gene system showed that miR-296-5p had the target binding to HIF-1α. Conclusions:HIF-1α plays a key role in the invasion and migration of hypoxia-induced pancreatic cancer cells through negatively reducing miR-296-5p.