Preparation and Characterization of Nanoliposomal Beta- Cryptoxanthin and its Effect on Proliferation and Apoptosis in Human Leukemia Cell Line K562

Purpose: To prepare beta-cryptoxanthin-loaded nanoliposomes and evaluate their anti-proliferative activity in leukemia K562 cell line, compared to free beta-cryptoxanthin.
Methods: Beta-cryptoxanthin-loaded nanoliposomes were prepared by extrusion method. Morphological characterization of the nanoliposomes was performed by cryo-transmission electron microscopy (cryo-TEM). The anti-proliferation effect of beta-cryptoxanthin (BC) in free and liposomal forms on K562 cell line was studied using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay. Apoptotic activity, following treatment with beta-cryptoxanthin in the free and liposomal forms, was detected using flow cytometry.
Results: Entrapment efficiency of beta-cryptoxanthin was 86.3 % ± 1.0. Cryo-TEM analysis revealed that the nanoliposomes have spherical shapes. In all conditions, beta-cryptoxanthin-loaded nanoliposomes exhibited greater anti-proliferative activity than than the free beta-cryptoxanthin (p < 0.001). Furthermore, in the presence of beta-cryptoxanthin-loaded nanoliposomes, the proportion of apoptotic cells was higher for free beta-cryptoxanthin (p < 0.001).
Conclusion: The data obtained indicate that beta-cryptoxanthin, especially in the liposomal form, inhibits the growth of K562 cells and may therefore provide a basis for the development of leukemia therapies.

Keywords
Beta-cryptoxanthin; Nanoliposome; Anti-proliferative; Apoptosis; Flow cytometry; Leukemia