Combination of PI3K/mTOR inhibition demonstrates efficacy in human chordoma

Background: Chordomas are rare tumors of the axial skeleton for which surgical resection remains the most reliable means of cure. PI-103 is a inhibitor of PI3K/AKT and mTOR activation. This study aims to determine whether the PI3K/mTOR pathway was active in chordomas and whether their inhibition could lead to decreased proliferation and increased apoptosis. Materials and Methods: Thirteen human chordoma were tested for activation of the PI3K/mTOR pathway. The human chordoma cell line UCH-1 was treated with increasing doses of PI-103. Inhibition of AKT and mTOR was examined and assays assessing proliferation and apoptosis were performed. Results: The chordoma specimen demonstrated activation of the PI3K/mTOR pathway. PI-103 inhibited the AKT and mTOR activation in the UCH-1 cell line. PI-103 inhibited proliferation and induced apoptosis in UCH-1. Conclusion: The PI3K/AKT and mTOR signaling pathway is constitutively activated in chordoma. PI-103 decreases proliferation and induces apoptosis in the UCH-1 via inhibition of the PI3K/mTOR pathway.