Targeting Macrophages Sensitizes Chronic Lymphocytic Leukemia to Apoptosis and Inhibits Disease Progression

Cell Rep. 2016 Feb 23;14(7):1748-1760. doi: 10.1016/j.celrep.2016.01.042. Epub 2016 Feb 11.

Abstract

The role of monocytes/macrophages in the development and progression of chronic lymphocytic leukemia (CLL) is poorly understood. Transcriptomic analyses show that monocytes/macrophages and leukemic cells cross talk during CLL progression. Macrophage depletion impairs CLL engraftment, drastically reduces leukemic growth, and favorably impacts mouse survival. Targeting of macrophages by either CSF1R signaling blockade or clodrolip-mediated cell killing has marked inhibitory effects on established leukemia also. Macrophage killing induces leukemic cell death mainly via the TNF pathway and reprograms the tumor microenvironment toward an antitumoral phenotype. CSF1R inhibition reduces leukemic cell load, especially in the bone marrow, and increases circulating CD20(+) leukemic cells. Accordingly, co-targeting TAMs and CD20-expressing leukemic cells provides a survival benefit in the mice. These results establish the important role of macrophages in CLL and suggest therapeutic strategies based on interfering with leukemia-macrophage interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal / pharmacology
  • Apoptosis / drug effects*
  • Apoptosis / immunology
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / pathology
  • Cell Communication / drug effects
  • Cell Line, Tumor
  • Clodronic Acid / pharmacology
  • Disease Progression
  • Gene Expression Regulation, Leukemic*
  • Humans
  • Leukemia, Lymphocytic, Chronic, B-Cell / drug therapy*
  • Leukemia, Lymphocytic, Chronic, B-Cell / genetics
  • Leukemia, Lymphocytic, Chronic, B-Cell / immunology
  • Leukemia, Lymphocytic, Chronic, B-Cell / mortality
  • Liposomes / pharmacology
  • Macrophages / drug effects*
  • Macrophages / immunology
  • Macrophages / pathology
  • Mice
  • Mice, Transgenic
  • Neoplasm Transplantation
  • Primary Cell Culture
  • Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / antagonists & inhibitors*
  • Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / genetics
  • Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / immunology
  • Signal Transduction
  • Survival Analysis
  • Transplantation, Heterologous
  • Tumor Microenvironment / drug effects

Substances

  • Antibodies, Monoclonal
  • Csf1r protein, mouse
  • Liposomes
  • Receptors, Granulocyte-Macrophage Colony-Stimulating Factor
  • Clodronic Acid