Engineered natural killer cells impede the immunometabolic CD73-adenosine axis in solid tumors

  1. Andrea M Chambers
  2. Kyle B Lupo
  3. Jiao Wang
  4. Jingming Cao
  5. Sagar Utturkar
  6. Nadia Lanman
  7. Victor Bernal-Crespo
  8. Shadia Jalal
  9. Sharon R Pine
  10. Sandra Torregrosa-Allen
  11. Bennett D Elzey
  12. Sandro Matosevic

  • Curated by eLife

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    Evaluation Summary:

    The authors have engineered an anti-CD73 chimeric antigen receptor (CAR) that they express in NK cells to counteract tumors bearing CD73, which contributes to the generation of immunosuppressive adenosine in the tumor microenvironment. This is a promising approach for a new anti-cancer immunotherapy and will be of interest to oncologists and cancer immunologists. The CAR-bearing NK cells show slightly enhanced tumor killing in vitro, but preliminary data show more promising results in mice. This could be due to the CD73 CAR blocking catalytic activity in the tumor microenvironment more effectively than directly promoting cytotoxicity responses.

    (This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #1 agreed to share their name with the authors.)

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Abstract

Immunometabolic reprogramming due to adenosine produced by CD73 (encoded by the 5’-ectonucleotidase gene NT5E ) is a recognized immunosuppressive mechanism contributing to immune evasion in solid tumors. Adenosine is not only known to contribute to tumor progression, but it has specific roles in driving dysfunction of immune cells, including natural killer (NK) cells. Here, we engineered human NK cells to directly target the CD73-adenosine axis by blocking the enzymatic activity of CD73. In doing so, the engineered NK cells not only impaired adenosinergic metabolism driven by the hypoxic uptake of ATP by cancer cells in a model of non-small-cell lung cancer, but also mediated killing of tumor cells due to the specific recognition of overexpressed CD73. This resulted in a ‘single agent’ immunotherapy that combines antibody specificity, blockade of purinergic signaling, and killing of targets mediated by NK cells. We also showed that CD73-targeted NK cells are potent in vivo and result in tumor arrest, while promoting NK cell infiltration into CD73 + tumors and enhancing intratumoral activation.

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  1. Version published to 10.7554/elife.73699 on eLife
  2. eLife

    Evaluation Summary:

    The authors have engineered an anti-CD73 chimeric antigen receptor (CAR) that they express in NK cells to counteract tumors bearing CD73, which contributes to the generation of immunosuppressive adenosine in the tumor microenvironment. This is a promising approach for a new anti-cancer immunotherapy and will be of interest to oncologists and cancer immunologists. The CAR-bearing NK cells show slightly enhanced tumor killing in vitro, but preliminary data show more promising results in mice. This could be due to the CD73 CAR blocking catalytic activity in the tumor microenvironment more effectively than directly promoting cytotoxicity responses.

    (This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #1 agreed to share their name with the authors.)

  3. eLife

    Reviewer #1 (Public Review):

    The authors have successfully engineered human NK cells expressing a chimeric antigen receptor (CAR) targeting CD73. CD73 is important enzyme for generating immunosuppressive adenosine in the tumor microenvironment, so it serves as a potential immunotherapeutic target to prevent production of adenosine and reverse the immunosuppression. Here the authors present data demonstrating the efficacy of their CAR-bearing NK cells in eliminating CD73-expressing tumors in vitro and in vivo.

    Strengths of the manuscript are:
    1. demonstration that the CAR can be efficiently expressed on the NK cell surface through lentiviral transduction
    2. demonstration that the CAR-bearing NK cells can better kill CD73-expressing target cells and suppress their production of adenosine
    3. data showing that the CAR-bearing NK cells can reduce the burden of CD73-expressing tumor cells in mice and that they seem to better infiltrate these tumors in vivo, as compared to NK cells lacking the CAR

    Weaknesses include:
    1. a need to better characterize whether or not the CAR is actually transducing activation signals into the NK cells when it engages with CD73 on tumor cells or if it is primarily functioning by inhibiting adenosine production to enhance natural cytotoxicity responses by the NK cells. This is a fundamental question that needs to be addressed to understand the basic function of the CAR-bearing NK cells.
    2. the in vivo studies of anti-tumor responses by CAR-bearing NK cells should be bolstered by analysis in more mice than currently presented

  4. eLife

    Reviewer #2 (Public Review):

    The manuscript by Chambers et al. seeks to address adenosine production, which is an immunosuppressive mechanism employed by many solid tumors. To do this, the authors chose to target CD73, which plays an important role in adenosine accumulation in the tumor microenvironment. The authors used natural killer (NK) cells genetically engineered with a chimeric antigen receptor (CAR) designed to target CD73, with the aim to increase NK cell anti-tumor activity against CD73+ lung adenocarcinoma. Major strengths of the manuscript are that the authors show successful modification of primary human NK cells using two methods (electroporation and transduction. Also, the CAR NK cells are tested in vivo in a mouse model and show decreased tumor burden in mice treated with their CD73 CAR-NK cells. Some weaknesses of the manuscript are that data are not always displayed in a manner that makes them easy to access for the reader and are, in some cases, incorrectly described. It is also not clear why the differences between unmodified NK cells have almost as strong anti-tumor activities as CAR-NK cells (e.g. figures 3+4). In total, the idea is of interest for the field of cancer immunotherapy.

  5. eLife

    Reviewer #3 (Public Review):

    Although the experiments were well performed, the manuscript could be improved by addressing the points below.
    1. CD73 could be induced on NK cells upon engagement with tumor cells, thereby impairing the antitumor effect of these engineered anti-CD73 CAR-NK cells in the TME. Thus, the authors should examine this possibility in their work.
    2. In Fig. 4C, the authors should add the control group "untransfected NK cells only".
    3. The tumor weight data (Fig. 5E) about the antitumor effect of anti-CD73 CAR-NK cells vs untransduced NK cells seem inconsistent with the survival data (Fig. 5B) as well as the bioluminescence data (Fig. 5C). Are there any significant differences of tumor weights among different groups?

  6. Version published to 10.1101/2021.10.05.463201v1 on bioRxiv