Aberrant Activation of the PI3K/mTOR Pathway Promotes Resistance to Sorafenib in AML

Abstract Therapy directed against oncogenic FLT3 has been shown to induce response in patients with AML, but these responses are almost always transient. To address the mechanism of FLT3 inhibitor resistance, we generated two resistant MV4-11 and MOLM-13 cell lines by sustained treatment with the FLT3 inhibitor sorafenib. MV4-11 cells express only FLT3-ITD, while MOLM-13 cells express wild-type FLT3 and FLT3-ITD. Both cell lines are dependent on FLT3 activation as sorafenib, PKC-412, and AC220, but not imatinib, dasatinib, nilotinib or bosutinib, inhibit cell survival in both cell lines. After treatment with sorafenib for 90 days, we observed that both cell lines displayed resistance to sorafenib as well as to AC220 suggesting that sustained treatment with an FLT3 inhibitor results in…