Screening Of TSP50Expression Inhibitor From Chinese Medicine Compounds And Analysis Of Its Antitumor Activity And Mechanisms

Testes-specific protease50(TSP50) is aberrantly expressed in many cancerbiopsies and plays a crucial role in tumorigenesis, which make it a potentialcancer therapeutic target for drug discovery.Here, we constructed a firefly luciferase reporter driven by the TSP50genepromoter to screen natural compounds capable of inhibiting the expression ofTSP50. Then we identified alantolactone and cardamonin could efficiently inhibitthe promoter activity of TSP50gene, further results revealed that they alsoefficiently inhibited the expression of TSP50in both mRNA and protein levels.Moreover, we found them could increase the ratio of Bax/Bcl-2, and activatecaspase-9and caspase-3in the cancer cells with high expression of TSP50, andcardamonin could induce G2/M phase arrest with downregulated cyclin E andupregulated p21and CDK2. Surprisingly, the same effects can also be observedin the same cells just by knockdown of TSP50gene expression. Furthermore, ourresults suggested that overexpression of TSP50decreased the cell sensitivity toalantolactone and cardamonin-induced apoptosis in those cancer cells.Taken together, these results suggest that alantolactone and cardamonininduce mitochondrial-dependent apoptosis and cardamonin induce G2/M phasearrest at least partially via down-regulation of TSP50expression. This work laida solid foundation for development of anticancer drugs targeting TSP50.