MTORC2/AKT Feedback Activation Restraint CPT-induced Inhibition Of HepG2 Cell Proliferation

Objective: to study the effect of Crytotanshinone on AKT activity and its suppression on growth of Hep G2 cells. Methods: the change of AKT phosphorylation treated by Crytotanshinone and the expression of c-PARP on combination treatment of PP242, an m TOR inhibitor, and Crytotanshinone, also the AKT pathway were measured by the western blot, the growth suppression of Hep G2 cells treated by Crytotanshinone combine MK2206 or PP242 was measured by CCK-8. Results: 1. Crytotanshinone enhance AKT phosphorylation in Hep G2 cells.2. Inhibition of loop back activation of AKT enhance growth suppression of Hep G2 cells treated by Crytotanshinone,we found MK2206 significantly enhance the suppression on growth of Hep G2 cells treated by Crytotanshinone. 3. m TORC2 activity involved in AKT phosphorylation treated by Crytotanshinone. Results show that PP242 reduced the enhancement of AKT phosphorylation by Crytotanshinone, means m TORC2 involved in this phenomenon. 4. The suppression of cells growth by Crytotanshinone was enhanced by m TORC2 inhibition. We found that cells growth was inhibited significantly when treatment combined Crytotanshinone and PP242.5. The inhibition of m TORC2 promoted the induction of apoptosis by Crytotanshinone. Due to the important role of AKT pathways in cancer cells, we proved that inhibition of m TORC2 enhanced the induction of apoptosis by Crytotanshinone.. Conclusion: in our study, m TORC2 phosphorylated AKT at S473, the suppression of Hep G2 cell growth by Crytotanshinone can be enhanced by inhibition of AKT or m TORC2. This provides a theoretical fundament on cancer therapy of Crytotanshinone and its combination usage.