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, Leukemi

Evaluating the effect of lycopene on telomerase activity in the human leukemia cell line K562

Background: Telomerase has been proposed as a novel and potentially selective target in cancer therapy. Many plant-derived products can induce apoptosis via telomerase inhibition. Lycopene (a carotenoid pigment) has been found to exhibit the various biological effects on different types of cancer cells, but its effect on telomerase activity has not been investigated. Therefore, this study aimed to examine the apoptosis-inducing effect of lycopene on human leukemia cell line K562, with particular emphasis on its effect on telomerase inhibition. Materials and Methods: Anti-proliferative effect of lycopene at different doses (0-20µm) and time intervals (24-72 h) on K562 cells was evaluated using the 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. To measure apoptosis, the Hoechst 33342 staining method and flow cytometry were used. The telomerase activity was determined using the telomeric repeat amplification protocol (TRAP) and ELISA assay.Results: The treatment of the K562 cells with lycopene dose-dependently resulted in a significant inhibition of cell growth and telomerase activity compared to the untreated cells. Furthermore, a positive correlation was found between telomerase inhibition and the induction of apoptosis in lycopene-treated K562 cells. Conclusion: The results of this study suggest a novel mechanism in the anti-cancer activity of lycopene in human leukemia K562 cells and may provide a basis for the future development of anti-telomerase agents