Clinical landscape of macrophage-reprogramming cancer immunotherapies

In triple negative breast cancer (TNBC), pro-tumoral macrophages promote metastasis and suppress the immune response. To target these cells, we engineered a previously identified CD206 (mannose receptor)-binding peptide, mUNO, to enhance its affinity and proteolytic stability. The new rationally designed peptide, MACTIDE, includes a trypsin inhibitor loop, from the Sunflower Trypsin Inhibitor-I. Binding studies to recombinant CD206 revealed a 15-fold lower KD for MACTIDE compared to parental mUNO. Additionally, mass spectrometry showed a 5-fold increase in half-life in tumor lysate for MACTIDE compared to mUNO. Homing studies in TNBC-bearing mice showed that fluorescein (FAM)-MACTIDE precisely targeted CD206+ tumor-associated macrophages (TAMs) upon intravenous, intraperitoneal and even oral administration, with no significant accumulation in liver. We coupled MACTIDE to the FDA-approved drug Verteporfin, an established photosensitizer for photodynamic therapy and inhibitor of the YAP/TAZ pathway, to generate a conjugate here referred to as MACTIDE-V. In the orthotopic 4T1 TNBC mouse model, non-irradiated MACTIDE-V-treated mice unexpectedly showed a similar anti-tumoral effect and fewer signs of toxicity as irradiated MACTIDE-V-treated mice, leading to subsequent studies on the laser-independent activity of this conjugate. In vitro studies using bone-marrow derived mouse macrophages showed that MACTIDE-V excluded YAP from the nucleus, increased the phagocytic activity and upregulated several genes associated with cytotoxic anti-tumoral macrophages. In mouse models of TNBC, MACTIDE-V slowed primary tumor growth, suppressed lung metastases, increased markers of phagocytosis and antigen presentation in TAMs and monocytes, increasing the tumor infiltration of several lymphocyte subsets. We therefore propose MACTIDE-V as a useful peptide-drug conjugate to modulate macrophage function in the context of breast tumor immunotherapy.

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Macrophages expressing chimeric cytokine receptors have an inflammatory phenotype and anti-tumoral activity upon IL-10 or TGFβ stimulation

Traxel,

Schmidt,

Beerli

et al. 2024

Preprint

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Background Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer that lacks hormone receptors and HER2 amplification, making it unresponsive to standard hormone or HER2-targeted therapies. Although immune checkpoint inhibitors (ICIs) have shown promise in tumors with high lymphocyte infiltration, their efficacy remains limited in tumors with minimal lymphocyte infiltration. To overcome this challenge, we developed a novel approach to reprogram tumor-associated macrophages (TAMs) from an immunosuppressive to an inflammatory phenotype within the tumor microenvironment (TME), aiming to enhance therapeutic outcomes in TNBC. Methods We designed a chimeric cytokine receptor (ChCR) that triggers STAT1 signaling upon stimulation with IL-10 or TGFβ, cytokines prevalent in the TME that typically drive immunosuppression. Human primary macrophages were transduced with a lentiviral vector expressing the ChCR, and changes in their phenotype, secretome, and transcriptome were analyzed following stimulation. The anti-tumoral activity of these reprogrammed macrophages was assessed using co-culture assays with 3D TNBC spheroids. Results ChCR expressing macrophages showed robust STAT1 activation in response to IL-10 or TGFβ stimulation, resulting in an inflammatory phenotype similar to IFNγ activation, as confirmed by phenotypic markers, and transcriptomic profiling. These ChCR-stimulated macrophages demonstrated significant anti-tumoral effects in 3D TNBC spheroids. Moreover, ChCR stimulation led to the upregulation of genes associated with good response to ICIs, among others CXCL9 and CXCL10, chemokines essential for lymphocyte recruitment. Secretion of CXCL10 was also confirmed by ELISA. Conclusion We successfully engineered a ChCR that reprograms TAMs within an IL-10- and TGFβ-rich environment, inducing an inflammatory phenotype and anti-tumoral activity. The expression of CXCL9 and CXCL10 further supports lymphocyte recruitment, potentially facilitating greater lymphocyte infiltration and disrupting the immunosuppressive TME. This approach offers a promising strategy to improve immunotherapy outcomes in TNBC patients, particularly those with low immune cell infiltration, thereby addressing a critical unmet clinical need.

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Clinical landscape of macrophage-reprogramming cancer immunotherapies

Cited by 4 publications

References 214 publications

Enhancing the anti-tumor activity and reprogramming M2 macrophages by delivering siRNAs against SIRPα and STAT6 via M1 exosomes and combining with anti-PD-L1

Enhancing the anti-tumor activity and reprogramming M2 macrophages by delivering siRNAs against SIRPα and STAT6 via M1 exosomes and combining with anti-PD-L1

Therapeutic Tumor Macrophage Reprogramming in Breast Cancer Through a Peptide-Drug Conjugate

Macrophages expressing chimeric cytokine receptors have an inflammatory phenotype and anti-tumoral activity upon IL-10 or TGFβ stimulation

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