Background and purpose:
Gambogic acid (GA) is a natural compound that exhibited a promising multi-target antitumor activity against several types of
cancer. However, the clinical application of this
drug is limited due to its poor solubility and low
tumor cell-specific delivery. In this study, the monomeric and dimeric
Cyclo (Arg-Gly-Asp) c(RGD)
tumor targeting
peptides (c(RGDfK) and E-[c(RGDfK)2]) were used to modify GA loaded nanostructured
lipid carriers (NLC) to reduce the limitations associated with GA and improve its antitumor activity. Methods: GA-NLC was prepared by emulsification and
solvent evaporation methods and the surface of the NLC was conjugated with the c(RGD)
peptides via an
amide bond. The formulations were characterized for particle size, morphology and zeta potential, encapsulation efficiency and
drug loading. The in-vitro cytotoxicity and cell uptake studies were conducted using 4T1 cell. Furthermore, the in-vivo antitumor activity and bio-distribution study were performed on female BALB/c nude mice. Results: The c(RGD)
peptides modified GA-NLC was successfully prepared with the particles size about 20 nm. The HPLC analysis, FT-IR and 1H-NMR spectra confirmed the successful conjugation of the
peptides with the NLC. The in-vitro cytotoxicity study on 4T1 cells revealed that c(RGD)
peptides modified GA-NLCs showed significantly higher cytotoxicity at 0.25 and 0.5 µg/mL as compared to unmodified GA-NLC. Furthermore, the cell uptake study demonstrated that better accumulation of E-[c(RGDfK)2]
peptides modified NLC in 4T1 cell after 12 h incubation. Moreover, the in-vivo study showed that c(RGD)s functionalized GA-NLC exhibited better accumulation in
tumor tissue and
tumor growth inhibition. In contrast to the monomeric c(
RGD) peptide, the dimeric c(
RGD) peptide (E-[c(RGDfK)2]) conjugated GA-NLC showed the improved antitumor activity and
tumor targeting ability of GA-NLC. Conclusion: These data provide further support for the potential clinical applications of E-[c(RGDfK)2]-GA-NLC in
breast cancer therapy.