Macrophage-Derived CXCL9 and CXCL10 Are Required for Antitumor Immune Responses Following Immune Checkpoint Blockade

  • Clin Cancer Res. 2020 Jan 15;26(2):487-504. doi: 10.1158/1078-0432.CCR-19-1868.
Imran G House  #  1  2 ,  Peter Savas  #  2  3 ,  Junyun Lai  1  2 ,  Amanda X Y Chen  1  2 ,  Amanda J Oliver  1  2 ,  Zhi L Teo  2  3 ,  Kirsten L Todd  1  2 ,  Melissa A Henderson  1  2 ,  Lauren Giuffrida  1  2 ,  Emma V Petley  1  2 ,  Kevin Sek  1  2 ,  Sherly Mardiana  1  2 ,  Tuba N Gide  4 ,  Camelia Quek  4 ,  Richard A Scolyer  4  5 ,  Georgina V Long  4  6  7 ,  James S Wilmott  4 ,  Sherene Loi  2  3 ,  Phillip K Darcy  #  8  2  9  10 ,  Paul A Beavis  #  8  2
Affiliations
  • 1. Cancer Immunology Program, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
  • 2. Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Australia.
  • 3. Division of Research, Peter MacCallum Cancer Centre, University of Melbourne, Melbourne, Victoria, Australia.
  • 4. The University of Sydney, Melanoma Institute Australia, Sydney, New South Wales, Australia.
  • 5. Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.
  • 6. Royal North Shore Hospital, Sydney, New South Wales, Australia.
  • 7. Mater Hospital, North Sydney, New South Wales, Australia.
  • 8. Cancer Immunology Program, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia. [email protected] [email protected].
  • 9. Department of Pathology, University of Melbourne, Parkville, Victoria, Australia.
  • 10. Department of Immunology, Monash University, Clayton, Victoria, Australia.
  • # Contributed equally.
PMID: 31636098 DOI: 10.1158/1078-0432.CCR-19-1868
Abstract

Purpose: Response rates to immune checkpoint blockade (ICB; anti-PD-1/anti-CTLA-4) correlate with the extent of tumor immune infiltrate, but the mechanisms underlying the recruitment of T cells following therapy are poorly characterized. A greater understanding of these processes may see the development of therapeutic interventions that enhance T-cell recruitment and, consequently, improved patient outcomes. We therefore investigated the chemokines essential for immune cell recruitment and subsequent therapeutic efficacy of these immunotherapies.

Experimental design: The chemokines upregulated by dual PD-1/CTLA-4 blockade were assessed using NanoString-based analysis with results confirmed at the protein level by flow cytometry and cytometric bead array. Blocking/neutralizing antibodies confirmed the requirement for key chemokines/cytokines and immune effector cells. Results were confirmed in patients treated with immune checkpoint inhibitors using single-cell RNA-sequencing (RNA-seq) and paired survival analyses.

Results: The CXCR3 ligands, CXCL9 and CXCL10, were significantly upregulated following dual PD-1/CTLA-4 blockade and both CD8+ T-cell infiltration and therapeutic efficacy were CXCR3 dependent. In both murine models and patients undergoing immunotherapy, Macrophages were the predominant source of CXCL9 and their depletion abrogated CD8+ T-cell infiltration and the therapeutic efficacy of dual ICB. Single-cell RNA-seq analysis of patient tumor-infiltrating lymphocytes (TIL) revealed that CXCL9/10/11 was predominantly expressed by Macrophages following ICB and we identified a distinct macrophage signature that was associated with positive responses to ICB.

Conclusions: These data underline the fundamental importance of macrophage-derived CXCR3 ligands for the therapeutic efficacy of ICB and highlight the potential of manipulating this axis to enhance patient responses.