Design, synthesis, and mechanism of anti-cancer activity of novel spiro tetramic acids

Targeted therapies have pioneered a more effective new pathway in cancer treatment by leveraging their precision-targeting advantages. Spiro tetramic acids are a kind of unique pyrrolidine-2,4-dione core structure containing a spiro ring structure, primarily employed as agro-chemicals with limited application in the field of anti-cancer. In this paper, fourteen novel 3-acetyl and 3-phenyl spiro tetramic acids were designed, synthesized, and evaluated for anti-proliferation in cancer cells. 3-Acetyl and 3-phenyl spirotetramic acids exhibited toxic effects against tested cancer cell lines. Among the 14 compounds, compound 8d was the most effective against RKO and H1299 with Half Maximal Inhibitory Concentration (IC₅₀) 3 ± 1 and 19 ± 2 μM. Further molecular structural prediction, bioinformatics analysis, and molecular docking revealed that compound 8d may target MMP1, MMP7 and PLK1. Additionally, 8d induced cell cycle arrest in G1 phase by increasing the expression of p21 protein and decreasing the expression of CCND1 and CCNB1 proteins. 8d also induced cell apoptosis through the mitochondrial pathways, as evidenced by alterations in the expressions of pertinent proteins, including Bcl-2 and Bax. These results indicated that the novel spirotetramine derivative 8d is a potential anti-cancer candidate drug and provides a new structural basis for the development of anti-cancer drugs.