Construction and effects of functionalized graphene oxide nonparticles-mediated RNA interference of hypoxia-inducible factor-1α gene

Objective To explore the effects of graphene oxide (GO)-polyethylene glycol (PEG)-folic acid (FA)-pyrenemethylamine hydrochloride (PyNH2)-mediated RNA interference (RNAi) of hypoxia-inducible factor-1α (HIF-1α) on the biological behaviors of human pancreatic cancer Patu8988 cells. Methods GO-PEG-FA-PyNH2 and RNAi targeting HIF-1α gene (GO-PEG-FA-PyNH2-HIF-1α-RNAi) was constructed. The expressions of HIF-1α and glucose transporter 1 (Glut-1) in Patu8988 cells were determined after knockdown of HIF-1α by RNAi. The invasive ability, the proliferation and the cell cycle of Patu8988 cells were investigated. The effect of HIF-1α knockdown on the uptake of 18F-fluorodeoxyglucose (FDG) in Patu8988 cells was also detected. Comparison of data was conducted by one-way analysis of variance and least significant difference t test. Results The GO-PEG-FA-PyNH2 was successfully constructed, and no cytotoxicity was found. Under the hypoxia or normoxia state, the mRNA and protein levels of HIF-1α and mRNA level of Glut-1 in cells transfected with GO-PEG-FA-PyNH2-HIF-1α-RNAi (study group) were lower than those in cells transfected with GO-PEG-FA-PyNH2(negative group) and cells transfected with Opti-minimal essential medium (Opti-MEM, control group; F=30.25-32.58, t=3.66-5.81, all P<0.05); the numbers of migrated cells in the study group were much lower than those in the negative group and the control group (F=38.63 and 41.35, t=20.51-35.25, all P<0.01); the cell proliferation in the study group was significantly lower than that in the negative group and the control group (F=35.19 and 38.11, t=15.11-22.19, all P<0.05). The proportions of G0/G1 cells in the study group were higher than those in the negative group and the control group (F=34.60 and 34.83, t=11.55-34.56, all P<0.05); the 18F-FDG uptake in the study group was lower than that in the negative group and control group (F=29.85 and 31.69, t=3.35-4.35, all P<0.05). Conclusion GO-PEG-FA-PyNH2-mediated HIF-1α RNAi inhibits the expression of HIF-1α in pancreatic cancer cells, leading to changes in related biological behaviors. Key words: Pancreatic neoplasms; Tumor cells, cultured; RNA, small interfering; Hypoxia-inducible factor 1, alpha subunit; Graphene oxide; Polyethylene glycols; Folic acid; 1-Pyrenemethylamine