Development of water-soluble prodrugs of the bisdioxopiperazine topoisomerase IIβ inhibitor ICRF-193 as potential cardioprotective agents against anthracycline cardiotoxicity

Figures

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  Figure 1. Chemical structures of bisdioxopiperazines, their metabolites and the prodrugs. Chemical structure of (a) dexrazoxane (DEX), its metabolite ADR-925 and (b) ICRF-193 and its proposed metabolite—ICRF-193met. (c) The activation pathway of sobuzoxane to ICRF-154. (d) General chemical structure of prepared prodrugs of ICRF-193.

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  Figure 2. Activation of the prodrugs in cell medium—DMEM. Concentration time profiles of the prodrugs, ICRF-193 and ICRF-193met obtained after incubation of (a) GK-667, (b) GK-678 and (c) GK-691 in DMEM (100 µM, 37 °C). Comparison of areas under the curve (AUC) of ICRF-193 and ICRF-193met assayed at (d) 3 h and (e) 48 h of the prodrugs incubation in DMEM (100 µM, 37 °C). Data are presented as mean +/− SD (n = 4). Statistical significance was evaluated using one-way ANOVA and Holm-Sidak’s post-hoc test (P ≤ 0.05).

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  Figure 3. Cytoprotective effects of ICRF-193 and the prodrugs against anthracycline induced toxicity in neonatal ventricular cardiomyocytes. Neonatal ventricular cardiomyocytes were pre-incubated with (a) ICRF-193, (b) GK-667, (c) GK-678 or (d) GK-691 for 3 h, then DAU was added for another 3 h incubation followed by a 45 h period in medium without DAU or prodrug. The cytotoxicity was determined spectrophotometrically as lactate dehydrogenase (LDH) release in culture medium. Data are presented as the mean +/− SD of four independent experiments. Statistical significance was evaluated using one-way ANOVA and Holm-Sidak’s post-hoc test; c—compared to control, d—compared to DAU; P ≤ 0.05.

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  Figure 4. Activation of GK-667 and ICRF-193 in DMEM, the buffer and NVCMs. Concentration time profiles of the compounds after incubation of (a) GK-667 or (b) ICRF-193 (both 100 µM, 37 °C) in DMEM (solid symbols) and the buffer (open symbols). (c) Concentration time profile after incubation of GK-667 (100 µM, 37 °C) in DMEM with (open symbols) and without (solid symbols) neonatal ventricular cardiomyocytes (NVCMs). (d) Intracellular concentrations of the compounds after incubation of GK-667 (100 µM, 37 °C) with NVCMs. Data were collected from four independent experiments and are presented as the mean +/− SD. Statistical analysis was calculated in GraphPad Prism 8.4.3 using t-test correct for multiple comparisons using the Holm-Sidak method; P ≤ 0.005. *-compared to buffer.

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  Figure 5. Activation of GK-667 and ICRF-193 in plasma in vitro. Concentration time profiles of the compounds after incubation of (a,b) GK-667 or (c,d) ICRF-193 in rabbit plasma in vitro (37 °C). The compounds were incubated in either (a,c) 100 or (b,d) 10 µM. Data are expressed as the mean +/− SD of four independent experiments.

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  Figure 6. Plasma concentration profiles of the prodrug, ICRF-193 and ICRF-193met after intravenous administration of GK-667 to rabbits. (a) Concentration time profiles of all compounds in plasma obtained after administration of GK-667 (5 mg/kg, i.v.) to rabbits (n = 6). Goodness-of-fit graphs of the population model of (b) ICRF-193 and (c) ICRF-193met. The solid and dashed lines represent the predicted median plasma concentrations and the 90% prediction intervals.