Discovery of the novel celastrol-based PROTACs for the treatment of non-small cell lung cancer.

Lung cancer is the world's top ranked cancer, with non-small cell lung cancer accounting for over 80% of lung cancer, so it is an urgent need to find new treatment strategies for non-small cell lung cancer. Celastrol is one of the effective active ingredients in the plant Tripterygium wilfordii Hook. f., and research has found that celastrol has an inhibitory effect on non-small cell lung cancer. However, the significant toxic side effect of celastrol limits its clinical application. In this study, 9 novel celastrol derivatives were developed using PROTAC technology. Cell viability testing displayed that some compounds exhibited higher antiproliferative activity in cancer cells, and had lower toxicity to normal cells. Among them, compound MX-108 (11c) showed a high inhibitory activity with an IC value of 0.66 ± 0.07 μM against human non-small cell lung cancer NCI-H358 cells. The DIA-based quantitative proteomics and western blot analyses had confirmed that compound MX-108 could effectively degrade RAB9A protein in NCI-H358 cells. Compound MX-108 could downregulate the phosphorylation level of Akt and upregulate the expression of cleaved caspase 3. Molecular docking predicted that celastrol had a high binding ability with RAB9A protein. Furthermore, compound MX-108 could effectively inhibit tumor growth in xenografts model of NCI-H358 cells. This study provides new ideas for the development of novel celastrol derivatives to treat cancer.