N-7-Guanine Adduct of the Active Monoepoxide of Prodrug Treosulfan: First Synthesis, Characterization, and Decomposition Profile Under Physiological Conditions

Romański, Michał; Girreser, Ulrich; Tężyk, Artur; Główka, Franciszek

doi:10.1016/j.xphs.2018.06.019

Cited by 5 publications

(17 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…30 Both in animal models and in vitro experiments, the half-lives of the THBG monoadduct and bis-N7G-BD cross-link in the DNA ranged from 2 to 6 days. 11,12,14,16,29 Recently, we have found that free HMSBG converted in the pH 7.2 phosphate buffer of 37 °C exclusively to EHBG at the half-life of 5.0 h. 20 Our present work revealed that HMSBG decomposed in the DNA according to first order kinetics at a rate constant of 0.0216 h −1 (half-life of 32 h), irrespective of the treosulfan concentration in the solution. We could not experimentally determine the contribution of spontaneous depurination (k B1 ) and epoxidation (k 3 ) to the total HMSBG decay.…”

Section: Discussionsupporting

confidence: 55%

“…On the basis of our previous works, we hypothesized that EBDM is capable of producing bis-N7G-BD and THBG independently of DEB, at the path involving HMSBG and EHBG. 20,26 Our studies provide evidence that HMSBG is an EBDMspecific DNA adduct, as it was present in calf thymus DNA exposed to treosulfan, the prodrug of EBDM and DEB, but not in the DNA exposed to DEB. Apart from HMSBG, the DNA exposed to treosulfan contained a significant portion of bis-N7G-BD and THBG that could not be attributed to DEB (Figure 1, Table 1).…”

Section: Discussionmentioning

confidence: 63%

“…Recently, we have reported that EBDM alkylates calf thymus DNA in vitro at the N-7 atom of guanine forming (2′ S ,3′ S )- N -7-(2′,3′-dihydroxy-4′-methylsulfonyloxybut-1′-yl)guanine adduct (HMSBG). We also found that at pH 7.2 and 37 °C, free HMSBG decomposes at a half-life of 5.0 h exclusively to EHBG, the precursor of the bis-N7G-BD cross-link . These results suggested that EBDM may participate in DNA cross-linking beyond the path involving DEB (Scheme ).…”

Section: Introductionmentioning

confidence: 63%

“…THBG, bis-N7G-BD, HMSBG, and the isotope-labeled internal standards, 15 N 5 -THBG and 15 N 10 -bis-N7G-BD, used to prepare calibration standards for a liquid chromatography−tandem mass spectrometry method (LC−MS/MS), were synthesized in our laboratory as described elsewhere. 20 Calf thymus DNA sodium salt (type I, fibers), primarily containing double stranded nucleic acid, was purchased from Sigma-Aldrich (Steinheim, Germany). Acetonitrile for HPLC, gradient grade, and formic acid, HPLC grade, were supplied by Merck KGaA (Darmstadt, Germany).…”

Section: Methodsmentioning

confidence: 99%

“…We also found that at pH 7.2 and 37 °C, free HMSBG decomposes at a half-life of 5.0 h exclusively to EHBG, the precursor of the bis-N7G-BD cross-link. 20 These results suggested that EBDM may participate in DNA cross-linking beyond the path involving DEB (Scheme 1). Then, after in vivo administration of treosulfan, the quantitative contribution of DEB and EBDM to this process would depend on the actual levels of these epoxides in the body and the rates of DNA alkylation.…”

Section: Introductionmentioning

confidence: 95%

See 4 more Smart Citations

Kinetics of in Vitro Guanine-N7-Alkylation in Calf Thymus DNA by (2S,3S)-1,2-Epoxybutane-3,4-diol 4-methanesulfonate and (2S,3S)-1,2:3,4-Diepoxybutane: Revision of the Mechanism of DNA Cross-Linking by the Prodrug Treosulfan

2019

Self Cite

View full text Add to dashboard Cite

Prodrug treosulfan, originally registered for treatment of ovarian cancer, has gained a use in conditioning prior to hematopoietic stem cell transplantation. Treosulfan converts nonenzymatically to the monoepoxide intermediate (EBDM), and then to (2S,3S)-1,2:3,4-diepoxybutane (DEB). The latter alkylates DNA forming mainly (2′S,3′S)-N-7-(2′,3′,4′-trihydroxybut-1′-yl)guanine (THBG) and (2S,3S)-1,4-bis(guan-7′-yl)butane-2,3-diol cross-link (bis-N7G-BD) via the intermediate epoxide adduct (EHBG). It is believed that DNA cross-linking by DEB is a primary mechanism for the anticancer and myeloablative properties of treosulfan, but clear evidence is lacking. Recently, we have proved that EBDM alkylates DNA producing (2′S,3′S)-N-7-(2′,3′-dihydroxy-4′-methylsulfonyloxybut-1′-yl)-guanine (HMSBG) and that free HMSBG converts to EHBG. In this paper, we investigated the kinetics of HMSBG, bis-N7G-BD, and THBG in DNA in vitro to elucidate the contribution of EBDM and DEB to treosulfan-dependent DNA–DNA cross-linking. Calf thymus DNA was exposed to (A) 100 μM treosulfan, (B) 200 μM treosulfan, and (C) DEB at a concentration 100 μM, exceeding that produced by 200 μM treosulfan. Following mild acid thermal hydrolysis of DNA, ultrafiltration, and off-line HPLC purification, the guanine adducts were quantified by LC–MS/MS. Both bis-N7G-BD and THBG reached highest concentrations in the DNA in experiment B. Ratios of the maximal concentration of bis-N7G-BD and THBG to DEB (adduct C max/DEB C max) in experiments A and B were 1.7–3.0-times greater than in experiment C. EHBG converted to the bis-N7G-BD cross-link at a much higher rate constant (0.20 h–1) than EBDM and DEB initially alkylated the DNA (1.8–3.4 × 10–5 h–1), giving rise to HMSBG and EHBG, respectively. HMSBG decayed unexpectedly slowly (0.022 h–1) compared with the previously reported behavior of the free adduct (0.14 h–1), which revealed the inhibitory effect of the DNA environment on the adduct epoxidation to EHBG. A kinetic simulation based on the obtained results and the literature pharmacokinetic parameters of treosulfan, EBDM, and DEB suggested that in patients treated with the prodrug, EBDM could produce the vast majority of EHBG and bis-N7G-BD via HMSBG. In conclusion, EBDM can produce DNA–DNA lesions independently of DEB, and likely plays a greater role in DNA cross-linking after in vivo administration of treosulfan than DEB. These findings compel revision of the previously proposed mechanism of the pharmacological action of treosulfan and contribute to better understanding of the importance of EBDM for biological effects.

show abstract

Section: Discussionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 63%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

See 3 more Smart Citations

Kinetics of in Vitro Guanine-N7-Alkylation in Calf Thymus DNA by (2S,3S)-1,2-Epoxybutane-3,4-diol 4-methanesulfonate and (2S,3S)-1,2:3,4-Diepoxybutane: Revision of the Mechanism of DNA Cross-Linking by the Prodrug Treosulfan

2019

Self Cite

View full text Add to dashboard Cite

show abstract

Nonenzymatic hydrolysis of 1,2:3,4‐diepoxybutane: A kinetic study including pH, temperature, and ion effects

Romański,

Mikołajewski,

Główka

2023

Int J of Chemical Kinetics

Self Cite

View full text Add to dashboard Cite

Abstract1,3‐Butadiene is a carcinogenic and mutagenic air pollutant metabolized to butane epoxides, among which 1,2:3,4‐diepoxybutane (DEB) exhibits the highest genotoxicity. DEB is also formed by 1,3‐butadiene oxidation in the air, producing a direct environmental and occupational exposure. In this paper, we studied the kinetics of the nonenzymatic hydrolysis of DEB at a wide range of pH and temperature, including the catalytic effect of ionic species. The compound degradation involved a general and specific acid‐base catalysis of the epoxide ring hydrolysis. DEB had the greatest stability at pH 5–9, when the rates of acid‐catalyzed and base‐catalyzed hydrolysis are negligible and the neutral hydrolysis predominates. The capability of the buffer anions to accelerate the DEB decay increased in the order H2PO4− < HCO3− < CH3COO− < HPO42− < and CO32−. The Arrhenius equation well described the influence of temperature on the acid‐catalyzed, base‐catalyzed, and neutral hydrolysis rate constants. According to the obtained hydrolysis model coupled with the found thermodynamic parameters, the half‐life of DEB in natural fresh waters spans from 2 days at 30°C to 31 days at 0°C, but in the laboratory waste adjusted to pH 1or 13, the half‐life shortens to 2–3 h at 20°C. Therefore, the results of the paper help to assess the risk of exposure to the genotoxic action of DEB.

show abstract

Population pharmacokinetic approach for evaluation of treosulfan and its active monoepoxide disposition in plasma and brain on the basis of a rat model

et al. 2020

Self Cite

View full text Add to dashboard Cite

Purpose Efficacy of treosulfan, used in the treatment of marrow disorders, depends on the activity of its monoepoxy—(EBDM) and diepoxy compounds. The study aimed to describe the pharmacokinetics of treosulfan and EBDM in the rat plasma and brain by means of mixed-effects modelling. Methods The study had a one-animal-per-sample design and included ninty-six 10-week-old Wistar rats of both sexes. Treosulfan and EBDM concentrations in the brain and plasma were measured by an HPLC–MS/MS method. The population pharmacokinetic model was established in NONMEM software with a first-order estimation method with interaction. Results One-compartment pharmacokinetic model best described changes in the concentrations of treosulfan in plasma, and EBDM concentrations in plasma and in the brain. Treosulfan concentrations in the brain followed a two-compartment model. Both treosulfan and EBDM poorly penetrated the blood–brain barrier (ratio of influx and efflux clearances through the blood–brain barrier was 0.120 and 0.317 for treosulfan and EBDM, respectively). Treosulfan plasma clearance was significantly lower in male rats than in females (0.273 L/h/kg vs 0.419 L/h/kg). Conclusions The developed population pharmacokinetic model is the first that allows the prediction of treosulfan and EBDM concentrations in rat plasma and brain. These results provide directions for future studies on treosulfan regarding the contribution of transport proteins or the development of a physiological-based model.

show abstract

N-7-Guanine Adduct of the Active Monoepoxide of Prodrug Treosulfan: First Synthesis, Characterization, and Decomposition Profile Under Physiological Conditions

Cited by 5 publications

References 24 publications

Kinetics of in Vitro Guanine-N7-Alkylation in Calf Thymus DNA by (2S,3S)-1,2-Epoxybutane-3,4-diol 4-methanesulfonate and (2S,3S)-1,2:3,4-Diepoxybutane: Revision of the Mechanism of DNA Cross-Linking by the Prodrug Treosulfan

Kinetics of in Vitro Guanine-N7-Alkylation in Calf Thymus DNA by (2S,3S)-1,2-Epoxybutane-3,4-diol 4-methanesulfonate and (2S,3S)-1,2:3,4-Diepoxybutane: Revision of the Mechanism of DNA Cross-Linking by the Prodrug Treosulfan

Nonenzymatic hydrolysis of 1,2:3,4‐diepoxybutane: A kinetic study including pH, temperature, and ion effects

Population pharmacokinetic approach for evaluation of treosulfan and its active monoepoxide disposition in plasma and brain on the basis of a rat model

Contact Info

Product

Resources

About