Engineered type 1 regulatory T cells designed for clinical use kill primary pediatric acute myeloid leukemia cells

Haematologica. 2021 Oct 1;106(10):2588-2597. doi: 10.3324/haematol.2020.263129.

Abstract

Type 1 regulatory (Tr1) T cells induced by enforced expression of IL-10 (LV-10) are being developed as a novel treatment for chemotherapy-resistant myeloid leukemias. In vivo, LV-10 cells do not cause graft vs host disease while mediating graft vs leukemia (GvL) effect against adult acute myeloid leukemia (AML). Since pediatric AML (pAML) and adult AML are different on a genetic and epigenetic level, we investigate herein whether LV-10 cells also efficiently kill pAML cells. We show that the majority of primary pAML are killed by LV-10 cells, with different levels of sensitivity to killing. Transcriptionally, pAML sensitive to LV-10 killing expressed a myeloid maturation signature. Overlaying the signatures of sensitive and resistant pAML onto the public NCI TARGET pAML dataset revealed that sensitive pAML clustered with M5 monocytic pAML and pAML with MLL rearrangement. Resistant pAML clustered with myelomonocytic leukemias and those bearing the core binding factor translocations inv(16) or t(8;21)(RUNX1-RUNX1T1). Furthermore, resistant pAML upregulated the membrane glycoprotein CD200, which binds to the inhibitory receptor CD200R1 on LV-10 cells. To examine if CD200 expression on target cells can impair LV-10 cell function, we overexpressed CD200 in myeloid leukemia cell lines ordinarily sensitive to LV-10 killing. Indeed, LV-10 cells degranulated less and killed fewer CD200-overexpressing cells compared to controls, indicating that pAML can utilize CD200 expression for immune evasion. Altogether, the majority of pAML are killed by LV-10 cells in vitro, supporting further LV-10 cell development as an innovative cell therapy for pAML.

MeSH terms

  • Adult
  • CD4-Positive T-Lymphocytes
  • Child
  • Graft vs Leukemia Effect
  • Humans
  • Leukemia, Myeloid, Acute* / genetics
  • Leukemia, Myeloid, Acute* / therapy
  • T-Lymphocytes, Regulatory*
  • Translocation, Genetic

Grants and funding

Funding: This work was supported by a Rising Tide Foundation for Clinical Cancer Research, Curesearch for Children’s Cancer Acceleration Initiative grant, Emerson Collective Cancer Research Fund, Alex’s Lemonade Stand Reach Grant, Children’s Leukemia Research Association, the CURE Childhood Cancer Foundation, and the Virginia and D.K. Ludwig Fund for Cancer Research. BC was supported by the Maternal and Child Health Research Institute Postdoctoral Fellowship. MJU was supported by an NSF DGE (1147470) and Blavatnik Family Fellowship.