In agreement with this observation, genetic and pharmacological ablation of FOXO1 inhibited the long-term proliferation and clonogenicity of AE cells and t(8;21) AML cell lines.
The overall results indicate that CCND1, FOXO1, and JUN may contribute to the induction of resistance to ATO, and that the C-Jun N-terminal kinase (JNK) signaling pathway may have greater significance than the phosphoinositide 3-kinase (PI3K)/Akt pathway in mediating the cytotoxic effects of ATO and the development of resistance to ATO in the HL-60 cell line.
Gata1 mutant cells that overexpress ERG with hyperactive AKT are characterized by diminished FOXO1/3a expression and an increased dependency on the c-Jun pathway similar to that seen in acute megakaryoblastic leukemia (AMKL) cell lines, acute myeloid leukemia (AML) with knockdown of FOXO3a, or AML with expression of myristoylated Akt.
In conclusion, the constitutive phosphorylation of FKHR was observed in the majority of AML, and the detection of phospho-FKHR might provide a new tool for identifying AML patients with an unfavorable outcome.
It is noteworthy that the t(X;11)(q13;q23) in the KARPAS 45 cell line and in one acute nonlymphoblastic leukemia (ANLL) disrupts the forkhead domain of the AFX protein exactly at the same amino acids as does the t(2;13)(q35;q14) in case of the FKHR protein.