Identification of CDK4/6 Inhibitors as Small Molecule NLRP3 Inflammasome Activators that Facilitate IL-1β Secretion and T Cell Adjuvanticity

J Med Chem. 2024 Sep 12;67(17):14974-14985. doi: 10.1021/acs.jmedchem.4c00516. Epub 2024 Aug 20.

Abstract

Several FDA-approved adjuvants signal through the NLRP3 inflammasome and IL-1β release. Identifying small molecules that induce IL-1β release could allow targeted delivery and structure-function optimization, thereby improving safety and efficacy of next-generation adjuvants. In this work, we leverage our existing high throughput data set to identify small molecules that induce IL-1β release. We find that ribociclib induces IL-1β release when coadministered with a TLR4 agonist in an NLRP3- and caspase-dependent fashion. Ribociclib was formulated with a TLR4 agonist into liposomes, which were used as an adjuvant in an ovalbumin prophylactic vaccine model. The liposomes induced antigen-specific immunity in an IL-1 receptor-dependent fashion. Furthermore, the liposomes were coadministered with a tumor antigen and used in a therapeutic cancer vaccine, where they facilitated rejection of E.G7-OVA tumors. While further chemical optimization of the ribociclib scaffold is needed, this study provides proof-of-concept for its use as an IL-1 producing adjuvant in various immunotherapeutic contexts.

MeSH terms

  • Adjuvants, Immunologic / chemistry
  • Adjuvants, Immunologic / pharmacology
  • Aminopyridines
  • Animals
  • Cancer Vaccines / immunology
  • Cancer Vaccines / pharmacology
  • Cyclin-Dependent Kinase 4* / antagonists & inhibitors
  • Cyclin-Dependent Kinase 4* / metabolism
  • Female
  • Humans
  • Inflammasomes* / drug effects
  • Inflammasomes* / metabolism
  • Interleukin-1beta* / metabolism
  • Liposomes / chemistry
  • Mice
  • Mice, Inbred C57BL
  • NLR Family, Pyrin Domain-Containing 3 Protein* / metabolism
  • Protein Kinase Inhibitors / chemistry
  • Protein Kinase Inhibitors / pharmacology
  • Purines* / chemistry
  • Purines* / pharmacology
  • Small Molecule Libraries / chemistry
  • Small Molecule Libraries / pharmacology
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism

Substances

  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Interleukin-1beta
  • Inflammasomes
  • Purines
  • Cyclin-Dependent Kinase 4
  • Adjuvants, Immunologic
  • ribociclib
  • Protein Kinase Inhibitors
  • Small Molecule Libraries
  • Liposomes
  • Cancer Vaccines
  • CDK4 protein, human
  • Aminopyridines