The BCL-2 inhibitor APG-2575 resets tumor-associated macrophages toward the M1 phenotype, promoting a favorable response to anti-PD-1 therapy via NLRP3 activation

Cell Mol Immunol. 2024 Jan;21(1):60-79. doi: 10.1038/s41423-023-01112-y. Epub 2023 Dec 7.


The main challenges in the use of immune checkpoint inhibitors (ICIs) are ascribed to the immunosuppressive tumor microenvironment and the lack of sufficient infiltration of activated CD8+ T cells. Transforming the tumor microenvironment (TME) from "cold" to "hot" and thus more likely to potentiate the effects of ICIs is a promising strategy for cancer treatment. We found that the selective BCL-2 inhibitor APG-2575 can enhance the antitumor efficacy of anti-PD-1 therapy in syngeneic and humanized CD34+ mouse models. Using single-cell RNA sequencing, we found that APG-2575 polarized M2-like immunosuppressive macrophages toward the M1-like immunostimulatory phenotype with increased CCL5 and CXCL10 secretion, restoring T-cell function and promoting a favorable immunotherapy response. Mechanistically, we demonstrated that APG-2575 directly binds to NF-κB p65 to activate NLRP3 signaling, thereby mediating macrophage repolarization and the activation of proinflammatory caspases and subsequently increasing CCL5 and CXCL10 chemokine production. As a result, APG-2575-induced macrophage repolarization could remodel the tumor immune microenvironment, thus improving tumor immunosuppression and further enhancing antitumor T-cell immunity. Multiplex immunohistochemistry confirmed that patients with better immunotherapeutic efficacy had higher CD86, p-NF-κB p65 and NLRP3 levels, accompanied by lower CD206 expression on macrophages. Collectively, these data provide evidence that further study on APG-2575 in combination with immunotherapy for tumor treatment is required.

Keywords: APG-2575; BCL-2; ICIs; Macrophages; NLRP3.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Cell Polarity / drug effects
  • Chemokine CCL5 / metabolism
  • Chemokine CXCL10 / metabolism
  • Dioxanes* / pharmacology
  • Dioxanes* / therapeutic use
  • Humans
  • Immune Checkpoint Inhibitors* / therapeutic use
  • Immunosuppression Therapy* / methods
  • Lung Neoplasms* / drug therapy
  • Mice
  • Mice, Inbred C57BL
  • NLR Family, Pyrin Domain-Containing 3 Protein* / agonists
  • Nitrobenzenes* / pharmacology
  • Nitrobenzenes* / therapeutic use
  • Proto-Oncogene Proteins c-bcl-2* / antagonists & inhibitors
  • Pyrroles* / pharmacology
  • Pyrroles* / therapeutic use
  • Transcription Factor RelA / metabolism
  • Tumor Microenvironment / drug effects
  • Tumor-Associated Macrophages* / drug effects
  • Tumor-Associated Macrophages* / metabolism
  • Xenograft Model Antitumor Assays


  • Dioxanes
  • Immune Checkpoint Inhibitors
  • Lisaftoclax
  • Nitrobenzenes
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Proto-Oncogene Proteins c-bcl-2
  • Pyrroles
  • Transcription Factor RelA
  • Chemokine CCL5
  • Chemokine CXCL10