Cytotoxicity of phosphoramidate, bis-amidate and cycloSal prodrug metabolites against tumour and normal cells.

ABSTRACT

Phosphonate and phosphate prodrugs are integral to enhancing drug permeability, but the potential toxicity of their metabolites requires careful consideration. This study evaluates the impact of widely used phosphoramidate, bis-amidate, and cycloSal phosph(on)ate prodrug metabolites on BxPC3 pancreatic cancer cells, GL261-Luc glioblastoma cells, and primary cultured mouse astrocytes. 1-Naphthol and 2-naphthol demonstrated the greatest toxicity. Notably, 2-naphthol exhibited an ED50 of 21 µM on BxPC3 cells, surpassing 1-naphthol with an ED50 of 82 µM. Real-time xCELLigence experiments revealed notable activity for both metabolites at a low concentration of 16 µM. On primary cultured mouse astrocyte cells, all prodrugs exhibited reduced viability at 128 to 256 µM after only 4 hours of exposure. A cell-type-dependent sensitivity to phosph(on)ate prodrug metabolites was evident, with normal cells showing greater susceptibility than corresponding tumour cells. The results suggest it is essential to consider the potential cytotoxicity of phosph(on)ate prodrugs in the drug design and evaluation process.