Targeted drug delivery system for cancer therapy using sonoporation

Objective: Ultrasound and microbubble, known as sonoporation, have been investigated with a view to improving the transfection efficiency of non-viral gene delivery systems. We have investigated the growth inhibitory effect in human gingival squamous cell carcinoma cell line, Ca9-22, by sonoporation. In this study, we examined the effect of the combination of sonoporation and anti-EGFR antibody.

Methods: The evaluation of gene transfer rate was performed using pVIVO1-GFP/LacZ. We used 528 cells to prepare anti-EGFR antibody. After the cells were cultured without fetal calf serum, the culture supernatant was collected to purify anti-EGFR antibody. We also prepared Fab fragment of anti-EGFR antibody. Ultrasound exposed to the mixture of Ca9-22 cells, anti-EGFR antibody, plasmid and microbubble (SonoVue). After the cells were incubated for 24 hours, X-Gal staining was performed. In anther experiment, the cytotoxity of bleomycin (BLM) delivered by sonoporation with anti-EGFR antibody was investigated using flowcytometric analysis and Hoechst staining in vitro assay system.

Results: Western blot analysis and flow-cytometric analyses revealed that anti-EGFR antibody actually bound to EGF receptor of Ca9-22 cells. We found that the addition of anti-EGFR antibody improved gene transfer rate and that an administration of BLM by sonoporation together with anti-EGFR antibody induced marked growth inhibition and apoptotic cell death of Ca9-22 cells, compared with control groups. Interestingly, the population of apoptotic cells remarkably increased when BLM was delivered by using sonoporation with Fab fragment of anti-EGFR antibody.

Conclusion: These findings indicate that the sonoporation with anti-EGFR antibody makes it possible that drugs are administrated into the cells more efficiently and specifically, suggesting the effective application for chemotherapy and gene therapy as treatment for oral squamous cell carcinoma.