Anti-human CD117 CAR T-cells efficiently eliminate healthy and malignant CD117-expressing hematopoietic cells

Leukemia. 2020 Oct;34(10):2688-2703. doi: 10.1038/s41375-020-0818-9. Epub 2020 May 1.

Abstract

Acute myeloid leukemia (AML) initiating and sustaining cells maintain high cell-surface similarity with their cells-of-origin, i.e., hematopoietic stem and progenitor cells (HSPCs), and identification of truly distinguishing leukemia-private antigens has remained elusive to date. To nonetheless utilize surface antigen-directed immunotherapy in AML, we here propose targeting both, healthy and malignant human HSPC, by chimeric antigen receptor (CAR) T-cells with specificity against CD117, the cognate receptor for stem cell factor. This approach should spare most mature hematopoietic cells and would require CAR T termination followed by subsequent transplantation of healthy HSPCs to rescue hematopoiesis. We successfully generated anti-CD117 CAR T-cells from healthy donors and AML patients. Anti-CD117 CAR T-cells efficiently targeted healthy and leukemic CD117-positive cells in vitro. In mice xenografted with healthy human hematopoiesis, they eliminated CD117-expressing, but not CD117-negative human cells. Importantly, in mice xenografted with primary human CD117-positive AML, they eradicated disease in a therapeutic setting. Administration of ATG in combination with rituximab, which binds to the co-expressed CAR T-cell transduction/selection marker RQR8, led to CAR T-cell depletion. Thus, we here provide the first proof of concept for the generation and preclinical efficacy of CAR T-cells directed against CD117-expressing human hematopoietic cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers
  • Biopsy
  • Bone Marrow / metabolism
  • Bone Marrow / pathology
  • Cell Line, Tumor
  • Disease Models, Animal
  • Gene Expression
  • Hematologic Neoplasms / diagnosis
  • Hematologic Neoplasms / immunology
  • Hematologic Neoplasms / metabolism
  • Hematologic Neoplasms / therapy
  • Hematopoietic Stem Cells / immunology
  • Hematopoietic Stem Cells / metabolism
  • Humans
  • Immunophenotyping
  • Immunotherapy, Adoptive*
  • Leukemia, Myeloid, Acute / genetics
  • Leukemia, Myeloid, Acute / immunology
  • Leukemia, Myeloid, Acute / pathology
  • Leukemia, Myeloid, Acute / therapy
  • Lymphocyte Depletion
  • Mice
  • Proto-Oncogene Proteins c-kit / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-kit / genetics
  • Proto-Oncogene Proteins c-kit / metabolism
  • Receptors, Antigen, T-Cell / genetics
  • Receptors, Antigen, T-Cell / immunology*
  • Receptors, Chimeric Antigen / genetics
  • Receptors, Chimeric Antigen / immunology*
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism*
  • Treatment Outcome
  • Xenograft Model Antitumor Assays

Substances

  • Biomarkers
  • Receptors, Antigen, T-Cell
  • Receptors, Chimeric Antigen
  • KIT protein, human
  • Proto-Oncogene Proteins c-kit