MicroRNA-222 Controls Human Pancreatic Cancer Cell Line Capan-2 Proliferation by P57 Targeting

Pancreatic cancer (PC) is one of the most common cancers and has a poor prognosis due to late diagnosis and ineffective therapeutic multimodality. MicroRNAs (miRNAs, miRs) are a group of non-coding, small RNAs with active biological activities. In our investigation, human pancreatic cancer cell line Capan-2 were transfected with miR-222 mimics, inhibitors or their negative controls. Cell proliferation was assessed by Cell Counting Kit-8 (CCK-8), EdU incorporation assay and cell cycle determination by flow cytometry. MiR-222 and putative target gene expression levels including p27, p57 and PTEN were determined using quantitative reverse transcription polymerase chain reactions and Western blotting. Our results showed that miR-222 could lead to increased vitality and proliferative rate of Capan-2 cells, and also higher S-phase and lower G1-phase of cell cycle. Further, we found p57 at protein level, but not p27 nor PTEN, was regulated by miR-222 in Capan-2 cells. Finally, we co-transfected miR-222 inhibitor and p57 si-RNA into Capan-2 cells, and found that proliferation-suppressing effects of miR-222 inhibitor on Capan-2 cells could be partially reversed by silencing p57. Our results indicate that miR-222 controls Capan-2 cell proliferation by targeting p57. This study provides a novel idea for developing effective therapeutic strategy for PC patients through inhibiting miR-222.