Activating caspase-8/Bid/ROS signaling to promote apoptosis of breast cancer cells by folate-modified albumin baicalin-loaded nanoparticles

Abnormal apoptosis can lead to uncontrolled cell growth, aberrant homeostasis or the accumulation of mutations. Therapeutic agents that re-establish the normal functions of apoptotic signaling pathways offer an attractive strategy for the treatment of breast cancer. Baicalin (BA) is one of the natural compounds with anti-proliferation and pro-apoptosis activities against numerous tumor cells. However, low bioavailability restricts the clinical application of BA. In order to improve its therapeutic efficacy and study the mechanism of actions, active targeting delivery systems were developed for targeting tumor environment and selective cell killing effects. It emphasized on the construction of folate-conjugated albumin nanoparticles loaded with baicalin (FA-BSANPs/BA) and mechanisms of which on the promotion of breast cancer apoptosis. The physicochemical properties and structural characteristics of FA-BSANPs/BA were investigated. Cell experiments were carried out to study the targeted anti-breast cancer effects of FA-BSANPs/BA and its mechanism. The results showed that FA-BSANPs/BA was successfully constructed with stable structural characteristics and sustained release effects. Cellular uptake and MTT showed that it increased targeted uptake efficiency and cytotoxicity. Flow cytometry and western blot confirmed that it promoted apoptosis by increasing the expression of caspase-8 and ROS, and decreasing the level of Bid. It is suggested that the pro-apoptotic mechanism of FA-BSANPs/BA is related to regulation of key proteins in extrinsic apoptotic pathway. In conclusion, FA-BSANPs/BA is a good delivery carrier and significantly inhibits the breast cancer growth compared with free BA. The mechanism of FA-BSANPs/BA promoting apoptosis of breast cancer may be due to its action on the caspase-8/Bid/ROS pathway.