Therapeutic Targeting of TIM-4-L With Engineered T Cells for Acute Myeloid Leukemia.

PURPOSE: Disruption of lipid bilayer asymmetry is a common feature observed in cancer cells and offers novel routes for therapeutic targeting. We utilized the natural immune receptor TIM-4 to interrogate for loss of plasma membrane phospholipid polarity in primary acute myelogenous leukemia (AML) samples and evaluated the anti-leukemic activity of TIM-4-L-directed T cell therapy in preclinical AML models.

METHODS: We performed FACs analysis on 33 primary AML bone marrow specimens and correlated TIM-4-L expression frequency and intensity with molecular disease characteristics. Using Kasumi-1 and MV-4-11 AML cell lines, we further tested the anti-leukemic effects of TIM-4-L-directed engineered T cells in vitro and in vivo.

RESULTS: 86% of untreated AML blasts displayed upregulation of cell surface TIM-4-L. These observations were agnostic to AML genetic classification, as samples with mutations in TP53, ASXL1, and RUNX1 displayed TIM-4-L upregulation similar to that seen in favorable and intermediate subtypes. TIM-4-L dysregulation was also stably present in AML cell lines. To evaluate the potential of targeting upregulated TIM-4-L with adoptive T cell therapy (ACT), we constructed TIM-4-L-directed engineered T cells, which demonstrated potent anti-leukemic effects, effectively eliminating AML cell lines with a range of endogenous TIM-4-L expression levels both in vitro and in vivo.

CONCLUSIONS: These results highlight TIM-4-L as a highly prevalent target on AML across a range of genetic classifications and novel target for T cell-based therapy in AML. Further investigations into the role of TIM-4-L in AML pathogenesis and its potential as an anti-leukemic target for clinical development are warranted.