Phenylethanoid Glycosides from Cistanche tubulosa Inhibits the Growth of B16-F10 Cells both in Vitro and in Vivo by Induction of Apoptosis via Mitochondria-dependent Pathway

Cistanche tubulosa phenylethanoid glycosides (CTPG) have been shown various biological activities including anti-allergy, hepatoprotective activity and bone regeneration. However, the anti-tumor activity of CTPG needs to be investigated. CTPG was used to treat B16-F10 cells both in vitro and in vivo. We found that CTPG dramatically changed the morphology of B16-F10 cells, and significantly reduced the viability of B16-F10 cells in a dose-dependent and time-dependent manner, which might be mediated by CTPG-induced apoptosis and cell cycle arrest. After CTPG treatment, the expressions of BAX and BCL-2 were up-regulated and down-regulated, respectively. Moreover, mitochondrial membrane potential was reduced and ROS generation was increased. Consequently, the levels of cytochrome c and cleaved-caspase-3 and -9 were up-regulated by CTPG treatment but not for cleaved-caspase-8. We further observed that CTPG significantly inhibited the tumor growth in vivo and improved the survival rate of tumor mice. We also observed that CTPG promoted the proliferation of splenocytes and increased the proportions of CD4+ and CD8+ T cells in spleens of tumor mice. The results showed that CTPG induced the apoptosis of B16-F10 cells through mitochondria-dependent pathway, suggesting that CTPG could be a potential candidate for treatment of cancer.