Aqueous Extracts of Toona sinensis Leaves Inhibit Renal Carcinoma Cell Growth and Migration Through JAK2/stat3, Akt, MEK/ERK, and mTOR/HIF-2α Pathways

Toona sinensis (TS) is a type of deciduous tree, which is distributed widely in Asia and used as a traditional herb medicine. Previously, we demonstrated that aqueous extracts of TS leaves (TSL-1) induce apoptosis in two clear types of human renal carcinoma cells (ccRCC) via mitochondria-dependent pathway. In this study, we further investigated the more detailed mechanism of TSL-1-induced antitumor effects on ccRCCs. TSL-1 treatment arrested ccRCC cells in G0/G1 phase through the decrease of cyclin D1, cyclin-dependent kinase (CDK)2, and CDK4 as well as induction of p53 and FOXO3a protein expressions. On the other hand, the inhibitory effects of TSL-1 on migration were also observed in 786-O and A-498 cells. Mechanically, we presented that TSL-1 could suppress cell cycle progression and motility via inhibiting the phosphorylation of JAK2/stat3, Akt, MEK/ERK, and mTOR in a concentration- and time-dependent manner. Moreover, we found that TSL-1 inhibited p21, HIF-2α, c-Myc, VEGF, and MMP9 protein expressions in both cell lines. In conclusion, these findings suggested that TS-induced apoptosis and its antimigration activity in ccRCC cells were accompanied by inactivation of several oncogenic pathways.