Ultrasound microbubble contrast agent enhances TRAIL gene transfection into hepatocellular carcino-ma cells

Abstract

Objective To evaluate the impact of the recombined plasmid vector with enhanced green fluorescent protein (EGFP) encoding soluble tumor necrosis factor related apoptesis inducing ligand (pIRES-EGFP-sTRAIL) on proliferation and apoptosis of human hepatocellular carcinoma cell line HepG2, and investi-gate the feasibility and efficiency of the transfection of pIRES- EGFP- sTRAIL into HepG2 by ultrasound micro-bubble contrast agent. Methods pIRES-EGFP-sTRAIL was constructed and transfected into HepG2 cells by using different types of mediated methods: microbubble echocontrast agent combining appropriate dose of ultra-sound irradiation, liposome method, microbubble echocontrast agent only or blank medium treatment. Transfec-tion efficiency was evaluated by EGFP-expressed cell count; proliferation-lnhibiting rate and the apoptosis rate of HepG2 cells were determined by MTT method and flow cytometry analysis; changes of cell morphology were examined by microscopy with Hoechst33258 dyeing; expression of caspase-8 and caspase-3 was detected by Western blot. Results Ultrasound microbubbh enhanced pIKES-EGFP-sTRAIL uptake by HepG2 cells, and the transfection efficiency was significantly higher in ultrasound microlmbble group than that in other groups( P<0.05 ) ; pIRES- EGFP- sTBAIL effectively inhibited HepG2 cell proliferation and induced cell apoptosis by triggering caspase cascade. Both the inhibiting rate and apoptosis rate were significantly higher in ultrasound microbubble group than those in other groups(P<0.05). Conclusion pIRES-EGFP-sTRAIL expresses ef-fectively in HepG2 cells, sTRAIL has a potential role on the inhibiting proliferation and inducing apoptosis of HepG2 cells by triggering caspase cascade, and this role can be enhanced by the administration of low-intensity ultrasound and microbubble echecontrast agent. Key words: Liver neoplasmas; Sonication; Microbubbles; Contrast media; Tumor necrosis factors