Ribosome Profiling Sequencing Reveals LPIN1 As a Potential Therapeutic Target for Acute Myeloid Leukemia with FLT3 -ITD Mutation

Internal tandem duplication mutations of FLT3 (FLT3-ITD) are the most frequent genetic alteration in adult acute myeloid leukemia (AML) and confer poor prognosis. The use of FLT3 inhibitors has improved outcome among FLT3-ITD mutant patients, but clinical efficacy is transient and limited, largely due to the emergence of drug resistance which can occur through activation of alternative signaling pathways or metabolic degradation of the inhibitors within the tumor microenvironment. Therefore, it is urgent to explore new intervention targets and develop novel therapeutic strategies for FLT3-ITD mutant AML.

In this study, we use ribosome profiling sequencing from 13 healthy donors and 35 AML patients (including 17 FLT3-ITD mutant AML cases and 18 non-FLT3-ITD mutant AML cases) to identify differentially expressed genes. In FLT3-ITD mutant AML patients, 143 up-regulated genes were obtained, which are mainly involved in cell adhesion, embryonic skeletal cell formation, coping with hypoxia, and T-cell activation etc. 538 down-regulated genes are mainly associated with signal transduction, cell differentiation etc. Among these up-regulated genes, we validated the abnormally elevated expression of LPIN1 in FLT3-ITD mutant AML patients using RT-PCR. LPIN1 has been previously reported to be a divalent magnesium ion-dependent phosphatidic acid phosphatase and play a key role in lipid metabolism. Analysis of clinical data from public databases indicated that high LPIN1 expression is positively correlated with poor prognosis in FLT3-ITD mutant AML patients.

In FLT3-ITD mutant AML cell lines, both shRNA-mediated knockdown of LPIN1 expression and pharmacological inhibition of LPIN1 activity suppressed cell proliferation and increased apoptosis, indicating that LPIN1 plays an important role in the growth and survival of FLT3-ITD mutant AML cells. The combination of the LPIN1 inhibitor Propranolol with the FLT3 inhibitor Quizartinib significantly reduced the cell proliferation of both FLT3-ITD AML cell lines and primary FLT3-ITD mutant AML patient samples. Furthermore, the combination of Propranolol with Quizartinib eradicated leukemic cells and prolonged survival in a xenograft FLT3-ITD mutant AML model.

In summary, our study demonstrates that LPIN1 plays a pivotal role in FLT3-ITD mutant AML pathogenesis and chemotherapy resistance. LPIN1 inhibition synergizes with FLT3 inhibitor to eliminate FLT3-ITD AML cells in vitro and in vivo, providing a new therapeutic target for FLT3-ITD mutant AML.