Background: The natural compound n-butylidenephthalide (BP) can pass through the blood-brain barrier to inhibit the growth of glioblastoma multiforme tumors. However, BP has an unstable structure that reduces its antitumor activity and half-life in vivo.
Objective: The aim of this study is to design a drug delivery system to encapsulate BP to enhance its efficacy by improving its protection and delivery.
Methods: To protect its structural stability against protein-rich and peroxide solutions, BP was encapsulated into a lipo-PEG-PEI complex (LPPC). Then, the cytotoxicity of BP/LPPC following preincubation in protein-rich, acid/alkaline, and peroxide solutions was analyzed by MTT. Cell uptake of BP/LPPC was also measured by confocal microscopy. The therapeutic effects of BP/LPPC were analyzed in xenograft mice following intratumoral and intravenous injections.
Results: When BP was encapsulated in LPPC, its cytotoxicity was maintained following preincubation in protein-rich, acid/alkaline, and peroxide solutions. The cytotoxic activity of encapsulated BP was higher than that of free BP (~4.5- to 8.5-fold). This increased cytotoxic activity of BP/LPPC is attributable to its rapid transport across the cell membrane. In an animal study, a subcutaneously xenografted glioblastoma multiforme mouse that was treated with BP by intratumoral and intravenous administration showed inhibited tumor growth. The same dose of BP/LPPC was significantly more effective in terms of tumor inhibition.
Conclusion: LPPC encapsulation technology is able to protect BP's structural stability and enhance its antitumor effects, thus providing a better tool for use in cancer therapy.
Keywords: antitumor; glioblastoma multiforme; lipo-PEG-PEI complex; n-butylidenephthalide.