Cellular distribution studies of the nitric oxide-generating antineoplastic prodrug O2-(2,4-dinitrophenyl)1-((4-ethoxycarbonyl)piperazin-1-yl)diazen-1-ium-1,2-diolate formulated in Pluronic P123 micelles

Objective Nitric oxide (NO) possesses antitumour activity. It induces differentiation and apoptosis in acute myeloid leukaemia (AML) cells. The NO prodrug O-2-(2,4-dinitrophenyl)1-((4-ethoxycarbonyl)piperazin-1-yl)diazen-1-ium-1,2-diolate, or JS-K, has potent antileukaemic activity. JS-K is also active in vitro and in vivo against multiple myeloma, prostate cancer, non-small-cell lung cancer, glioma and liver cancer. Using the Pluronic P123 polymer, we have developed a micelle formulation for JS-K to increase its solubility and stability. The goal of the current study was to investigate the cellular distribution of JS-K in AML cells. Methods We investigated the intracellular distribution of JS-K (free drug) and JS-K formulated in P123 micelles (P123/JS-K) using HL-60 AML cells. We also studied the S-glutathionylating effects of JS-K on proteins in the cytoplasmic and nuclear cellular fractions. Key findings Both free JS-K and P123/JS-K accumulate primarily in the nucleus. Both free JS-K and P123/JS-K induced S-glutathionylation of nuclear proteins, although the effect produced was more pronounced with P123/JS-K. Minimal S-glutathionylation of cytoplasmic proteins was observed. Conclusions We conclude that a micelle formulation of JS-K increases its accumulation in the nucleus. Post-translational protein modification through S-glutathionylation may contribute to JS-K's antileukaemic properties.