Coexpression profile of leukemic stem cell markers for combinatorial targeted therapy in AML

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• Targeted immunotherapy for acute myeloid leukemia (AML) faces challenges due to a lack of AML-specific antigens and clonal heterogeneity.
• These challenges can lead to on-target off-leukemia toxicity and disease relapse from minor AML clones.
• Combinatorial targeting strategies are hypothesized to enhance therapeutic efficacy without increasing toxicity.

Purpose of the Study:

• To identify target antigen combinations specific for AML and leukemic stem cells.
• To evaluate the potential of combinatorial targeting to improve AML immunotherapy outcomes.

Main Methods:

• Generated a protein expression profile using flow cytometry on primary AML (n=356) and normal bone marrow samples (n=34).
• Analyzed expression of CD33, CD123, CLL1, TIM3, CD244, and CD7 on AML bulk and leukemic stem cells at diagnosis and relapse.
• Evaluated coexpression of target antigens in dual combinations, comparing AML cells with normal hematopoiesis and non-hematopoietic tissues.

Main Results:

• CD33, CD123, CLL1, TIM3, and CD244 were ubiquitously expressed on AML cells at diagnosis and relapse, regardless of genetic features.
• All analyzed targets showed some expression in normal hematopoiesis.
• Combinations of CD33/TIM3 and CLL1/TIM3 demonstrated significantly higher expression on AML cells compared to normal tissues.

Conclusions:

• Combinatorial targeting of CD33/TIM3 or CLL1/TIM3 presents a promising strategy for AML immunotherapy.
• This approach may enhance therapeutic efficacy while mitigating toxicity.
• Further investigation into these combinations could lead to improved AML treatment protocols.