Design of lipid-based formulations for oral delivery of a BASP1 peptide targeting MYC-dependent gastrointestinal cancer cells

Abstract

Hypothesis

Oral delivery of the proliferation-inhibiting brain acid-soluble protein 1 effector domain peptide (Myr-NT) towards MYC-dependent gastrointestinal tumors can be achieved by forming hydrophobic ion pairs (HIPs) and incorporating them into lipid-based formulations.

Experiments

Hydrophobic ion pairing of fluorescently-labelled Myr-NT (Myr-NT-TAMRA) was performed, increase in lipophilicity was assessed, and the most promising HIP was subsequently incorporated into a nanoemulsion. Stability of the peptide towards degradation by trypsin was evaluated. Anti-proliferative and anti-invasive measurements were performed upon application of the loaded nanoemulsion on various MYC-dependent human cancer cell lines. Cellular uptake and molecular effect were complementary investigated by confocal laser scanning microscopy (CLSM) and by immunoblot analyses, respectively.

Findings

HIPs of Myr-NT-TAMRA exhibited up to 10,000-fold increase in lipophilicity, thereby enabling incorporation into a nanoemulsion. The formulation significantly boosted stability of incorporated peptide towards enzymatic degradation by trypsin. Furthermore, anti-proliferative measurements on human cancer cell lines revealed superior biological activity of the loaded nanoemulsion compared to the native peptide particularly in lymphoma cells, but also in colorectal cancer cells. Thereby, a correlation with proliferation inhibition as well as differences in MYC protein expression were observed. Finally, CLSM imaging revealed up to 15-fold increased cellular uptake of Myr-NT-TAMRA from the nanoemulsion confirming efficient intracellular delivery of the peptide.

Conclusion

Myr-NT can be efficiently delivered into intestinal tumor cells using orally administered lipid-based formulations.