Carotenoids inhibit proliferation and regulate expression of peroxisome proliferators-activated receptor gamma (PPARγ) in K562 cancer cells

► β-Carotene, astaxanthin, capsanthin, and bixin were chosen to treat K562 cells. ► Carotenoids decreased the viability of leukemia K562 cells, induced cell apoptosis, and interfered with cell cycle progression in dose- and time-dependent manners. ► Pretreatment with GW9662, a potent antagonist of PPARγ, partly attenuated the inhibition of K562 cells by carotenoid. ► Carotenoids up-regulated the expression of PPARγ, p21 and Nrf2 but down-regulated the expression of cyclin D1 in a dose-dependent manner. ► PPARγ signaling pathways and Keap1-Nrf2/EpRE/ARE signaling pathway were involved in the inhibition of K562 cell proliferation by carotenoids.