Background: Phosphoinositide-Dependent Kinase 1 (PDK1) is now widely studied in malignant
solid tumors. Researchers have previously revealed that targeting PDK1 is thought of as a promising anticancer
treatment strategy. The aim of this study was designed to evaluate the anticancer activity of GSK-470, a novel
and highly specific inhibitor of PDK1, in Pheochromocytoma (PCC) tumor model.
Methods: PC12 cells were xenografted into nude mice to build PCC tumor model. Animals were treated with
GSK-470 vs vehicle. Mean tumor volume was calculated and compared across groups. TUNEL was used to
detect apoptosis. The effects of PDK1 inhibitor GSK-470 on activation of the Akt signaling and its downstream
Akt/mTOR pathway in xenotransplant tumor tissues were examined by western bolt.
Results: The mean tumor volume in GSK-470 group was significantly less than that in control group. TUNEL
results found that cell apoptosis was markedly increased in GSK-470 group compared with the control group.
The western bolt analysis showed that the phosphorylation of Akt at threonine 308 was significantly reduced in
GSK-470 group. Also, GSK-470 strongly inhibited phosphorylation of mTOR on Ser2448, a marker for
mTORC1 activity, as well as phosphorylation of p70S6K, best characterized targets of mTOR.
Conclusion: Our results showed that GSK-470 exhibited potent anticancer activity in PC12 tumor-bearing mice.
Also, we found that this effect appeared to be mediated by the inhibition of the Akt/mTOR pathway. The present
study once again provides new insights into the therapeutic effects of inhibiting PDK1 in the treatment of malignant
PCC. Therefore, we propose that GSK-470 might be an effective therapeutic agent for the treatment of