Aryloxy Diester Phosphonamidate Prodrugs of Phosphoantigens (ProPAgens) as Potent Activators of Vγ9/Vδ2 T-Cell Immune Responses.

Hachemi Kadri,Qin Xu,Benjamin E Willcox,Richard T Bryan,Maria Sharif,Elizabeth Ashby,Taher E Taher,Youcef Mehellou

doi:10.1021/acs.jmedchem.0c01232

Hachemi Kadri, Qin Xu + Show 6 more

Open Access

https://doi.org/10.1021/acs.jmedchem.0c01232

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Abstract

Vγ9/Vδ2 T-cells are activated by pyrophosphate-containing small molecules known as phosphoantigens (PAgs). The presence of the pyrophosphate group in these PAgs has limited their drug-like properties because of its instability and polar nature. In this work, we report a novel and short Grubbs olefin metathesis-mediated synthesis of methylene and difluoromethylene monophosphonate derivatives of the PAg (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBP) as well as their aryloxy diester phosphonamidate prodrugs, termed ProPAgens. These prodrugs showed excellent stability in human serum (t1/2 > 12 h) and potent activation of Vγ9/Vδ2 T-cells (EC50 ranging from 5 fM to 73 nM), which translated into sub-nanomolar γδ T-cell-mediated eradication of bladder cancer cells in vitro. Additionally, a combination of in silico and in vitro enzymatic assays demonstrated the metabolism of these phosphonamidates to release the unmasked PAg monophosphonate species. Collectively, this work establishes HMBP monophosphonate ProPAgens as ideal candidates for further investigation as novel cancer immunotherapeutic agents.

Highlights

Vγ9/Vδ2 T-cells are the dominant subtype of human γδ Tcells in adult peripheral blood.[1]
Given the high potency of HMBPP ProPAgen presented in this work, we subsequently studied their specificity toward the activation of Vγ9/Vδ2 T-cells
ProPAgen derivatives, and which we have previously reported.[20]. These prodrugs were specific and potent activators of Vγ9/Vδ2 T-cells in peripheral blood mononuclear cells (PBMCs) assays and this translated into potent sensitization of the urinary bladder carcinoma cell line T24 to Vγ9/Vδ2 T-cellmediated lysis

Summary

Introduction

Vγ9/Vδ2 T-cells are the dominant subtype of human γδ Tcells in adult peripheral blood.[1]. These observations have made the Vγ9/Vδ2 subset a major focus of investigation for the therapeutic exploitation of γδ T-cells.[3]

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