Genetic Inactivation of CD33 in Hematopoietic Stem Cells: A Strategy to Enable CAR-T Cell Immunotherapy in Acute Myeloid Leukemia (AML)

• Grant number: 25/03164-1
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2025
• End date: April 30, 2026
• Field of knowledge: Biological Sciences - Genetics
• Principal Investigator: Eduardo Magalhães Rego
• Grantee: Maria Fernanda Madrid Mendoza
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 13/08135-2 - CTC - Center for Cell-Based Therapy, AP.CEPID

Abstract

Acute myeloid leukemia is an aggressive hematologic malignancy with high incidence in adults and poor prognosis, especially in elderly patients. Standard therapy, based on chemotherapy and bone marrow transplantation, is associated with significant toxicity and high relapse rates. Immunotherapy with CAR-T cells has revolutionized the treatment of hematologic neoplasms, such as acute lymphoblastic leukemia, but its use in AML is limited by the expression of the CD33 antigen on healthy myeloid cells, which causes severe toxicity. This study aims to develop an innovative strategy to overcome the toxicity associated with anti-CD33 CAR-T cell therapy in acute myeloid leukemia. To achieve this, the study proposes the genetic inactivation of CD33 in hematopoietic stem cells (HSCs) using CRISPR/Cas9 technology. The selective elimination of CD33 in HSCs aims to preserve normal hematopoiesis, while anti-CD33 CAR-T cells are directed exclusively to attack leukemic cells, enhancing the efficacy and safety of the treatment. This approach has the potential to improve the effectiveness and safety of therapy by reducing the side effects associated with the depletion of healthy myeloid cells. The strategy includes genetic editing of HL-60 cells and CD34+ HSCs, generation of functional CAR-T cells, and pre-clinical evaluation in in vitro and in vivo models. Expected outcomes include optimized protocols and robust data on safety and efficacy. This approach promises to improve the safety and effectiveness of therapy, positioning Brazil at the forefront of research in immunotherapy and gene editing for AML and other hematologic malignancies.