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. 2015 Feb 1;6(2):1212-1218.
doi: 10.1039/c4sc02574a. Epub 2014 Nov 14.

Bioorthogonal prodrug activation driven by a strain-promoted 1,3-dipolar cycloaddition

Siddharth S Matikonda  1 , Douglas L Orsi  1 , Verena Staudacher  1 , Imogen A Jenkins  1 , Franziska Fiedler  1 , Jiayi Chen  1 , Allan B Gamble  1
Affiliations

Bioorthogonal prodrug activation driven by a strain-promoted 1,3-dipolar cycloaddition

Siddharth S Matikonda et al. Chem Sci. .

Abstract

Due to the formation of hydrolysis-susceptible adducts, the 1,3-dipolar cycloaddition between an azide and strained trans-cyclooctene (TCO) has been disregarded in the field of bioorthogonal chemistry. We report a method which uses the instability of the adducts to our advantage in a prodrug activation strategy. The reaction of trans-cyclooctenol (TCO-OH) with a model prodrug resulted in a rapid 1,3-dipolar cycloaddition with second-order rates of 0.017 M-1 s-1 and 0.027 M-1 s-1 for the equatorial and axial isomers, respectively, resulting in release of the active compound. 1H NMR studies showed that activation proceeded via a triazoline and imine, both of which are rapidly hydrolyzed to release the model drug. Cytotoxicity of a doxorubicin prodrug was restored in vitro upon activation with TCO-OH, while with cis-cyclooctenol (CCO-OH) no activation was observed. The data also demonstrates the potential of this reaction in organic synthesis as a mild orthogonal protecting group strategy for amino and hydroxyl groups.

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Figures

Scheme 1
Scheme 1. 1,3-dipolar cycloaddition reported by Shea.
Fig. 1
Fig. 1. Proposed general strategy for prodrug activation via a 1,3-dipolar cycloaddition. The targeting ligand could be an antibody, peptide or small molecule.
Scheme 2
Scheme 2. Conditions: (i) NaNO2, 5 M HCl then NaN3, 0 °C, 73%; (ii) 4-nitrophenyl chloroformate, pyridine, DCM, 25 °C, 57%; (iii) 7-hydroxycoumarin, Et3N, DMF, 25 °C, 38%; (iv) 7-amino-4-methylcoumarin, triphosgene, toluene, reflux, then 4-azidobenzyl alcohol, 25 °C, 30%; (v) doxorubicin·HCl, Et3N, 4 Å molecular sieves, DMF, 25 °C, 69%.
Scheme 3
Scheme 3. Model prodrug activation strategy.
Fig. 2
Fig. 2. Release of 7-hydroxycoumarin 13a from 8a and 7-amino-4-methylcoumarin 13b from 8b in PBS : MeCN (1 : 1), measured by fluorescence (ex 360, em 455). Error represented as ±SD (n = 3).
Fig. 3
Fig. 3. 1H NMR experiments in: (a) CDCl3 (filtered through basic alumina) and (b) CD3CN/D2O (9 : 1); monitoring 1,3-dipolar cycloaddition between TCO 2 and probe 8a. Legend: key structural proton shifts illustrated; #: coumarin probe 8a; *: triazoline 11a; ■: aldimine 12a; : 7-hydroxycoumarin 13a; $: exocyclic aldehyde 14a; !: TCO 2; I.S.: Internal Standard, 4-iodonitrobenzene.
Scheme 4
Scheme 4. In vitro activation of prodrug 9.
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References

    1. Trounce J. R. Br. J. Clin. Pharmacol. 1979;8:205–207. - PMC - PubMed
    1. Collins I., Workman P. Nat. Chem. Biol. 2006;2:689–700. - PubMed
    1. Mahato R., Tai W., Cheng K. Adv. Drug Delivery Rev. 2011;63:659–670. - PMC - PubMed
    1. Rautio J., Kumpulainen H., Heimbach T., Oliyai R., Oh D., Jarvinen T., Savolainen J. Nat. Rev. Drug Discovery. 2008;7:255–270. - PubMed
    1. Warnecke A., Drug Delivery in Oncology: From Basic Research to Cancer Therapy, ed. F. Kratz, P. Senter and H. Steinhagen, Wiley-VCH, Weinheim, Germany, 1st edn, 2011, pp. 553–589.