Panax notoginseng saponins improves the malignancy of chronic myeloid leukemia by inducing cell apoptosis and autophagy

In recent years, the anti-tumor effect of panax notoginseng saponins (PNS) has been widely acknowledged by multiple in vivo and in vitro experiments. However, few studies have focused on the effect of PNS on chronic myeloid leukemia cells. In this study, we mainly explored the effect of PNS on K562 cell apoptosis and autophagy, thereby exploring its potential application in the treatment of chronic myeloid leukemia (CML) in clinic. Firstly, we found that PNS suppressed K562 cell viability in a timeand dose-dependent manner. Then, Hoechst staining and Annexin V-PI stainning showed that PNS significantly induced K562 cells apoptosis. Meanwhile, western blot analysis indicated enhanced expression of cleaved-caspase-3 and Bax after PNS treatment. Further study showed that PNS treatment increased K562 cell autophagy. We also found the reduced levels of p210, and phosphorylated PI3K, Akt, mTOR, p70S6K, 4E-BP1 as well as enhanced Beclin1 and LC3II expression after PNS treatment. More importantly, our data showed that overexpression of p210 could significantly abolish PNS-induced suppression of PI3K/Akt/mTOR signaling. In summary, PNS induced K562 cell apoptosis and autophagy mainly by suppressing p210/PI3K/Akt/mTOR signaling, which may shed light on the treatment of CML.