Conjugation of Doxorubicin to siRNA Through Disulfide-based Self-immolative Linkers

Florian Gauthier (1) , Jean-Rémi Bertrand (2) , Jean-Jacques Vasseur (1) , Christelle Dupouy (1) , Francoise Debart (1)

1 IBMM - Institut des Biomolécules Max Mousseron [Pôle Chimie Balard]
2 METSY - Aspects métaboliques et systémiques de l'oncogénèse pour de nouvelles approches thérapeutiques

Co-delivery systems of siRNA and chemotherapeutic drugs have been developed as an attractive strategy to optimize the efficacy of chemotherapy towards cancer cells with multidrug resistance. In these typical systems, siRNAs are usually associated to drugs within a carrier but without covalent interactions with the risk of a premature release and degradation of the drugs inside the cells. To address this issue, we propose a covalent approach to co-deliver a siRNA-drug conjugate with a redox-responsive self-immolative linker prone to intracellular glutathione-mediated disulfide cleavage. Herein, we report the use of two disulfide bonds connected by a pentane spacer or a p-xylene spacer as self-immolative linker between the primary amine of the anticancer drug doxorubicin (Dox) and the 2 ' -position of one or two ribonucleotides in RNA. Five Dox-RNA conjugates were successfully synthesized using two successive thiol-disulfide exchange reactions. The Dox-RNA conjugates were annealed with their complementary strands and the duplexes were shown to form an A-helix sufficiently stable under physiological conditions. The enzymatic stability of Dox-siRNAs in human serum was enhanced compared to the unmodified siRNA, especially when two Dox are attached to siRNA. The release of native Dox and RNA from the bioconjugate was demonstrated under reducing conditions suggesting efficient linker disintegration. These results demonstrate the feasibility of making siRNA-drug conjugates via disulfide-based self-immolative linkers for potential therapeutic applications.

Mots clés: Doxorubicin; siRNA; Conjugation; Disulfide bond; Self-immolative linker; Thiol- disulfide exchange

Domaines: Chimie analytique; Chimie; Chimie organique; Chimie thérapeutique

Florian Gauthier, Jean-Rémi Bertrand, Jean-Jacques Vasseur, Christelle Dupouy, Francoise Debart. Conjugation of Doxorubicin to siRNA Through Disulfide-based Self-immolative Linkers. Molecules, 2020, 25 (11), pp.2714. ⟨10.3390/molecules25112714⟩. ⟨hal-02991729⟩