Combined administration of naringenin and hesperetin with optimal ratio maximizes the anti-cancer effect in human pancreatic cancer via down regulation of FAK and p38 signaling pathway

Background: We have previously reported the functional anti-cancer effects of the products of enzymatic hydrolysis of Citrus unshiu peel (εCUP) and fermented extraction of Citrus unshiu peel (ƒCUP) in human pancreatic cancer. Despite their different characteristics and effects, the underlying mechanism remains elusive.

Purpose: In this study, we further demonstrate the impact of ingredient contents of Citrus unshiu peel on the cancer's natural features.

Methods: Anti-pancreatic cancer activities following combined treatment of naringenin and hesperetin were demonstrated in vitro and in vivo experiments.

Results: Combined treatment with naringenin and hesperetin inhibited the growth of human pancreatic cancer cells (εCUP mimic condition, p < 0.001 for Miapaca-2 cells) through induction of caspase-3 cleavage compared to separate treatment with naringenin or hesperetin. Combined treatment with naringenin and hesperetin also inhibited the migration (εCUP mimic condition, p < 0.001 for Panc-1 cells) of human pancreatic cancer cells. The εCUP mimic condition had the most effective anti-cancer features; in contrast, which had no inhibitory effect on growth and migration of normal cells (HUVECs and Detroit551 cells). In addition, εCUP mimic condition inhibited the phosphorylation of focal adhesion kinase (FAK) and p38 signaling compared with separate treatment with naringenin or hesperetin. Of note, εCUP mimic condition showed a prominent anti-growth effect (p < 0.001) compared with control or ƒCUP mimic condition in vivo xenograft models.

Conclusion: These results suggest that combined treatment with naringenin and hesperetin might be a promising anti-cancer strategy for pancreatic cancers without eliciting toxicity on normal cells.