An anti-mesothelin targeting antibody drug conjugate induces pyroptosis and ignites antitumor immunity in mouse models of cancer

Nicole L Wittwer; Alexander H Staudacher; Vasilios Liapis; Pina Cardarelli; Harriet Warren; Michael P Brown

doi:10.1136/jitc-2022-006274

An anti-mesothelin targeting antibody drug conjugate induces pyroptosis and ignites antitumor immunity in mouse models of cancer

J Immunother Cancer. 2023 Mar;11(3):e006274. doi: 10.1136/jitc-2022-006274.

Authors

Nicole L Wittwer^{1

2}, Alexander H Staudacher^{3

2}, Vasilios Liapis^{3

2}, Pina Cardarelli⁴, Harriet Warren³, Michael P Brown^{3

5}

Affiliations

¹ Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, South Australia, Australia Nicole.Wittwer@sa.gov.au.
² Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.
³ Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, South Australia, Australia.
⁴ GPCR Therapeutics USA, Redwood City, California, USA.
⁵ Cancer Clinical Trials Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia.

Abstract

Background: Emerging evidence suggests that the mechanism of chemotherapy-induced cell death may influence the antitumor immune response in patients with cancer. Unlike immunologically silent apoptosis, pyroptosis is a lytic and inflammatory form of programmed cell death characterized by pore formation in the cell membrane and release of proinflammatory factors. Gasdermin E (GSDME) has recently gained attention after cleavage of GSDME by certain chemotherapeutics has been shown to elicit pyroptosis. This study investigated the immunomodulatory effects of a mesothelin-targeting antibody drug conjugate (ADC) in mouse models of breast and colon cancer.

Methods: The antitumor effects of the ADC were studied in EMT6 breast cancer and CT26 colon cancer syngeneic mouse models. The immunomodulatory effects of the ADC were assessed by analysis of tumor-infiltrating immune cells using flow cytometry. ADC mechanism of action was evaluated by morphology, biological assays, ADC-mediated cleavage of key effector proteins, and CRISPR/Cas9-mediated knockout (KO). Finally, the antitumor effect of ADC and Fms-like tyrosine kinase-3 ligand (Flt3L) combination therapy was evaluated in tumors expressing GSDME as well as in GSDME-silenced tumors.

Results: The data demonstrated that the ADC controlled tumor growth and stimulated anticancer immune responses. Investigation of the mechanism of action revealed that tubulysin, the cytotoxic payload of the ADC, induced cleavage of GSDME and elicited pyroptotic cell death in GSDME-expressing cells. Using GSDME KO, we showed that GSDME expression is critical for the effectiveness of the ADC as a monotherapy. Combining the ADC with Flt3L, a cytokine that expands dendritic cells in both lymphoid and non-lymphoid tissues, restored control of GSDME KO tumors.

Conclusions: Together, these results show for the first time that tubulysin and a tubulysin containing ADC can elicit pyroptosis, and that this fiery cell death is critical for antitumor immunity and therapeutic response.

Keywords: dendritic cells; drug therapy, combination; immunity; therapies, investigational; tumor microenvironment.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Antibodies
Apoptosis
Colonic Neoplasms* / drug therapy
Disease Models, Animal
Immunoconjugates* / pharmacology
Immunoconjugates* / therapeutic use
Mice
Pyroptosis

Substances

Antibodies
Immunoconjugates