Targeted regulation of microRNA-222 on PTEN expression and its effect on invasion and migration of pan-creatic cancer cells

ZHANG Hongwei; WANG Cairu

doi:10.3969/j.issn.1009-0460.2019.11.007

Abstract：Objective To investigate the effect of microRNA-222 ( miR-222) on the targeted regulation of phosphatase and tensin homologue deleted from chromosome 10 (PTEN) and the invasion and migration of pancreatic cancer SW1990 cells. Methods SW1990 cells were cultured routinely in vitro and divided into experimental group, negative control group and blank control group. Cells in the experimental group were transfected with miR-222 inhibitor. The negative control group was transfected with negative control se-quence, and no transfection was performed in the blank control group. The miR-222 level, proliferative activity, wound healing rate and number of transmembrane cells were measured by real-time quantitative PCR ( QPCR), cell counting kit ( CCK)-8, scratch test and Transwell test. The levels of PTEN, matrix metalloproteinase (MMP)-2 and MMP-9 were measured by QPCR and Western blotting. The 3’ untranslated region (3’UTR) wild-type and mutant-type plasmids of PTEN gene were constructed and the targeting relationship between miR-222 and PTEN was verified by double luciferase reporter gene system. Results The miR-222 level in the experimental group was 0. 316±0. 046, lower than 1. 129±0. 213 in negative control group and 1. 147± 0. 274 in blank control group ( P＜0. 05). Compared with blank control group and negative control group, the proliferative activity of SW1990 cells in the experimental group de-creased at 48 and 72 h after transfection (P＜0. 05). The healing rate and the number of transmembrane cells in the experimental group were (21. 36±2. 79)% and 182. 62 ± 14. 85, lower than (65. 82 ± 5. 71)% and 379. 84 ± 20. 52 in the negative control group and (67. 19±6. 03)% and 384. 01±19. 20 in the blank control group (P＜0. 05). Compared with blank control group and negative control group, the MMP-9 and MMP-2 levels in the experimental group decreased, while PTEN levels increased ( P＜0. 05). Compared with cells transfected with mutant PTEN 3’UTR plasmid, miR-222 can reduce the luciferase activity of wild type 3’UTR ( P＜0. 05), but has no effect on the mutant 3’UTR (P＞0. 05). Conclusion Down-regulating miR-222 level in SW1990 cells can inhibit the prolifera- tion, migration and invasion of SW1990 cells and reduce the expression of MMP-2 and MMP-9. It may play a role in promoting cancer by targeting PTEN, which has a certain value in the targeted treatment of pancreatic cancer.