RESUMO
Cancers harboring homozygous deletion of the glycolytic enzyme enolase 1 (ENO1) are selectively vulnerable to inhibition of the paralogous isoform, enolase 2 (ENO2). A previous work described the sustained tumor regression activities of a substrate-competitive phosphonate inhibitor of ENO2, 1-hydroxy-2-oxopiperidin-3-yl phosphonate (HEX) (5), and its bis-pivaloyoxymethyl prodrug, POMHEX (6), in an ENO1-deleted intracranial orthotopic xenograft model of glioblastoma [Nature Metabolism 2020, 2, 1423-1426]. Due to poor pharmacokinetics of bis-ester prodrugs, this study was undertaken to identify potential non-esterase prodrugs for further development. Whereas phosphonoamidate esters were efficiently bioactivated in ENO1-deleted glioma cells, McGuigan prodrugs were not. Other strategies, including cycloSal and lipid prodrugs of 5, exhibited low micromolar IC50 values in ENO1-deleted glioma cells and improved stability in human serum over 6. The activity of select prodrugs was also probed using the NCI-60 cell line screen, supporting its use to examine the relationship between prodrugs and cell line-dependent bioactivation.
Assuntos
Glioblastoma , Glioma , Organofosfonatos , Pró-Fármacos , Humanos , Pró-Fármacos/uso terapêutico , Pró-Fármacos/farmacocinética , Organofosfonatos/farmacologia , Homozigoto , Deleção de Sequência , Fosfopiruvato Hidratase/genética , Fosfopiruvato Hidratase/metabolismo , Glioblastoma/tratamento farmacológico , Ésteres , Lipídeos , Proteínas de Ligação a DNA , Biomarcadores Tumorais , Proteínas Supressoras de Tumor/genéticaRESUMO
Homozygous deletion of methylthioadenosine phosphorylase (MTAP) in cancers such as glioblastoma represents a potentially targetable vulnerability. Homozygous MTAP-deleted cell lines in culture show elevation of MTAP's substrate metabolite, methylthioadenosine (MTA). High levels of MTA inhibit protein arginine methyltransferase 5 (PRMT5), which sensitizes MTAP-deleted cells to PRMT5 and methionine adenosyltransferase 2A (MAT2A) inhibition. While this concept has been extensively corroborated in vitro, the clinical relevance relies on exhibiting significant MTA accumulation in human glioblastoma. In this work, using comprehensive metabolomic profiling, we show that MTA secreted by MTAP-deleted cells in vitro results in high levels of extracellular MTA. We further demonstrate that homozygous MTAP-deleted primary glioblastoma tumors do not significantly accumulate MTA in vivo due to metabolism of MTA by MTAP-expressing stroma. These findings highlight metabolic discrepancies between in vitro models and primary human tumors that must be considered when developing strategies for precision therapies targeting glioblastoma with homozygous MTAP deletion.
Assuntos
Neoplasias Encefálicas/genética , Encéfalo/patologia , Desoxiadenosinas/metabolismo , Glioblastoma/genética , Purina-Núcleosídeo Fosforilase/deficiência , Tionucleosídeos/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Encéfalo/efeitos dos fármacos , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Meios de Cultivo Condicionados/metabolismo , Desoxiadenosinas/análise , Feminino , Secções Congeladas , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Homozigoto , Humanos , Metabolômica , Metionina Adenosiltransferase/metabolismo , Terapia de Alvo Molecular/métodos , Medicina de Precisão/métodos , Proteína-Arginina N-Metiltransferases/metabolismo , Purina-Núcleosídeo Fosforilase/genética , Deleção de Sequência , Tionucleosídeos/análise , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Glycolysis inhibition remains aspirational in cancer therapy. We recently described a promising phosphonate inhibitor of enolase for cancers harboring homozygous deletions of ENO1. Here, we describe the application of a nitroheterocycle phosphonoamidate pro-drug pair to capitalize on tumor hypoxia. This bioreducible prodrug exhibits greater-than 2-fold potency under hypoxic conditions compared to normoxia and exhibits robust stability in biological fluids. Our work provides strong in vitro proof-of-concept for using bioreduction as a pro-drug delivery strategy in the context of enolase inhibition.