External effect of honokiol on U937 cell

AIM: To investigate the anti-proliferative and apoptosis-inducing effect of honokiol on U937 cell line in vitro. METHODS: Proliferation of U937 cells and PBMCs were analyzed by MTT assay. Flow Cytometry and cell morphological observation were performed to find out whether honokiol could affect cell cycle and induce apoptosis of U937 as well as PBMCs in vitro. RT-PCR and Western blotting techniques were used to detect the changes in mRNA expression and protein production of bcl-2 and bax in U937 cells after treated with honokiol. RESULTS: Honokiol could significantly inhibit the proliferation of U937 cells at IC_ 50 concentration of 11.8 μg/mL, but slightly inhibit the proliferation of PBMCs, at IC_ 50 concentration of 40.3 μg/mL, respectively. Most honokiol-treated cells were arrested at G_0/G_1 phase. CONCLUSION: Honokiol could inhibit the proliferation and induce apoptosis of U937 cells, while has little effect on the proliferation and survival of PBMCs. Bax might be involved in the gene regulation related to honokiol-induced apoptosis.