Improving in vivo delivery of antisense MORF using a Herceptin/streptavidin nanoparticle

Abstract

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Objectives: We have improved cellular delivery in culture of an antisense MORF streptavidin nanoparticle using tat as a transfecting carrier. We have in vitro evidence that the internalizing Herceptin antibody may be a more effective carrier. In this study we provide evidence that Herceptin may also be effective in vivo for this purpose.

Methods: The antiRhoC mRNA MORF with a 3’ lissamine group was biotinylated via its 5’ primary amine and added with biotinylated Herceptin to streptavidin to prepare the 1:1 MORF/Herceptin nanoparticle. Stability of these nanoparticles in vitro and in vivo was previously established. Nude mice with study SUM190 (Her2+, RhoC+) or control SUM149 (Her2-, RhoC+) breast cancer xenografts each received 1.8 µg of antisense MORF as the MORF/Herceptin nanoparticle. After sacrificed at 6 to 24 h, tumor slices were viewed under fluorescence microscopy using tumors from mice receiving the identical nanoparticle but without the lissamine to control for background fluorescence.

Results: The fluorescence intensity of SUM190 samples under fluorescence microscopy was much stronger than that of SUM149 samples as evidence of unimpaired Herceptin targeting. Microscopy of the SUM190 tumor cells showed fluorescence mainly distributed in the cytoplasm and nucleus as evidence of internalization. Subcellular distribution of fluorescence in SUM149 tumor cells was too low for evaluation.

Conclusions: Internalizing antitumor antibody Herceptin can be used as an efficient carrier in vitro of antisense MORF and we now show similar properties following in vivo delivery.