MicroRNA-520b inhibits pancreatic cancer cell invasion and promotes apoptosis by targeting phosphofructokinase liver type

Objective To investigate the mechanism of microRNA (miRNA, miR)-520b targeting the regulation of hepatic phosphofructokinase liver type (PFKL) in pancreatic cancer cell invasion and apoptosis. Methods Cells were divided into blank group, negative control group, miR-520b positive group, miR-520b inhibition group and siRNA-PFKL group, and repeat 3 times per group. Real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) was used to detect the relative expression of miR-520b and PFKL genes. Western blotting was used to detect the levels of PFKL and epithelial-mesenchymal transition-related molecular proteins. Cell in vitro invasion assay (Transwell) and flow cytometry were used to detect cell invasion and apoptosis, respectively. Results The luciferase reporter gene assay showed that the luciferase activity of the miR-520b positive group (0.25±0.04) was significantly lower than that of the negative control group (0.92±0.09) in wild-type PFKL (P 0.05). Compared with the blank group [PFKL: 1.72±0.13, N-cadherin: 1.36±0.10, E-cadherin: 1.27±0.09, β-catenin: 0.36±0.04, Snail: 1.35±0.12, invasion: (23.27±3.18)/HF, apoptosis: (9.89±0.72)%] and the negative control group [PFKL: 1.61±0.12, N-cadherin: 1.40±0.11, E-cadherin: 1.26±0.08, β-catenin: 0.38±0.05, Snail: 1.30±0.10, invasion: (21.92±3.65)/HF, apoptosis: (10.67±0.69)%], the levels of E-cadherin protein and apoptosis were significantly increased in the miR-520b positive group [PFKL: 0.12±0.01, N-cadherin: 0.30±0.03, E-cadherin: 2.42±0.21, β-catenin: 0.19±0.02, Snail: 0.40±0.07, invasion: (12.13±1.39)/HF, apoptosis: (25.83±2.15)%] and the siRNA-PFKL group [PFKL: 0.11±0.01, N-cadherin: 0.25±0.02, E-cadherin: 2.53±0.24, β-catenin: 0.26±0.05, Snail: 0.22±0.04, invasion: (13.91±1.10)/HF, apoptosis: (23.91±1.99)%], and the levels of PFKL, N-cadherin, β-catenin, Snail protein and cell invasion were significantly reduced (P<0.05). However, the level of E-cadherin protein and apoptosis in the miR-520b inhibition group [PFKL: 3.47±0.25, N-cadherin: 3.39±0.20, E-cadherin: 0.49±0.03, β-catenin: 2.11±0.15, Snail: 2.05±0.22、invasion: (43.22±7.85)/HF, apoptosis: (2.41±0.18)%] was significantly decreased, and the levels of PFKL, N-cadherin, β-catenin, Snail protein and cell invasion were significantly increased (P<0.05). Conclusion MiR-520b can inhibit the invasion of pancreatic cancer cells and promote its apoptosis, and its mechanism is closely related to the regulation of target gene PFKL. Key words: Pancreatic cancer; MicroRNA; Invasion; Apoptosis; Phosphofructokinase liver type