Effect of placental growth factor gene silencing on migration and invasion of human pancreatic carcinoma cell line PANC1

Objective To explore the effect of inhibiting placental growth factor (PIGF) by small interfering RNA (siRNA) on migration, invasion and chemoresistance of human pancreatic cancer cell line PANC1. Methods Three specific siRNAs targeting PIGF (siRNA-PIGF) were designed. PANC1 cells were transfected with siRNA-PIGF by liposome transfection using untransfected cells as blank controls and nonspecific siRNA(siRNA-NC) transfected cells as negative controls. The PIGF mRNA and protein expression was examined by real-time RT-PCR and ELISA. MTT method was used to assess the inhibition rate of chemotherapeutic reagents on cell proliferation. The abilities of migration and invasion were evaluated by Transwell assay. Results The inhibition rate of PIGF mRNA in PANC1 cells transfected by 3 siRNA-PIGF were (64.38±8.92)%, (70.48±7.72)% and(81.25±6.02)%, which was lowest in siRNA-PIGF-3 transfected cells. The expression of PIGF mRNA in PANC1 cells were decreased by (63.72±8.20)% at 24 h after siRNA-PIGF transfection compared with siRNA-NC transfected cells; and the level of PIGF protein in the supernatant of cultured PANC1 cells was lowered by (42.92±1.34)% compared with siRNA-NC transfected cells and by (46.25±3.64)% compared with untransfected cells at 48h after transfection, which all had significant difference. There was no statistical difference between untransfected and siRNA-NC transfected cells. After 3 ng/L gemicitabine treatment, the inhibition rate of cell proliferation in siRNA-PIGF group was even higher than that in siRNA-NC and untransfected group[(44.35±5.05)% vs(34.29±3.60)% and(31.01±1.08)%; both P<0.05], and no significant difference was not observed after 5-FU and adriamycin treatment. In migration and invasion assay, the number of transmembrane cells from siRNA-PIGF group was 38.1% and 28.2% of that from siRNA-NC group and 40.8% and 36.2% of that from untransfected group, which had statistical difference(all P<0.05). Conclusions PIGF silencing could significantly suppress the migration and invasion of PANC1 cells and improve the sensitivity to gemicitabine. Key words: Pancreatic neoplasms; RNA, small interfering; Placental growth factor; Neoplasm invasiveness