Novel Spiropyrazolone Analogues Induce Apoptosis Via Eliciting Oxidative Stress In Lung Cancer Cells

Chemotherapy drugs developed based on the characteristics of abnormal redox balance of cancer cells have been widely used in clinical practice.The exuberant cellular metabolism and proliferation of cancer cells require high levels of reactive oxygen species（ROS）to maintain.Therefore,compared with normal cells,cancer cells have higher levels of ROS and are more susceptible to exogenous ROS regulator to increase ROS levels in cancer cells above the toxicity threshold,and ROS levels above the toxicity threshold will cause irreparable damage to the cells.Based on this theory,the strategy of disrupting the function of the antioxidant system by inducing excessive ROS production,resulting in irreparable cellular damage,is widely used in the development of chemotherapy drugs.In recent years,it is reported that spiropyrazolone analogues have anti-cancer activities,which can induce cycle arrest and apoptosis.Based on the above theoretical basis,this thesis evaluated the ability of inhibiting cancer cell proliferation to obtain spiropyrazolone analogue with outstanding biological activity,and investigated its anticancer mechanism of action.The main contents are as follows:1.This thesis first described the generation and regulation of intracellular ROS,and then introduces the effects of ROS on cancer cells,as well as anti-cancer strategies based on ROS.The progress of research on the biological activities related to spiropyrazolone analogues was outlined.2.In this thesis,8 spiropyrazolone analogues（Xu-1 to Xu-8）were evaluated for their ability to inhibit cell proliferation in several lung cancer cell lines,and the compound Xu-6 was obtained to show higher anticancer activity in NCI-H226 cells with IC₅₀=1.90μM.Activation of apoptosis signature proteins Caspase-3 and PARP and upregulation of m RNA levels of the G2/M phase checkpoint CDC2 and Cyclin B1genes suggested that Xu-6 induces apoptosis and G2/M phase arrest.Xu-6 induced a large accumulation of ROS as well as inhibited the activity of intracellular antioxidant Trx R,indicating that Xu-6 interferes with the redox homeostasis of NCI-H226 cells.Meanwhile,the addition of the antioxidant NAC was able to partially reduce the cytotoxicity of Xu-6 and rescue NCI-H226 cells from apoptosis,demonstrating that Xu-6 interferes with cellular redox system homeostasis by inducing the accumulation of intracellular ROS,which caused DNA damage and eventually led to apoptosis.In conclusion,this thesis proposed reasonable an explanation for the anticancer mechanism of spiropyrazolone analogues and laid the foundation to develop of spiropyrazolone analogues as antitumor drugs.