Single-trigger dual-responsive nanoparticles for controllable and sequential prodrug activation

Abstract

Here we have developed a novel approach where two synergistically acting drugs were completely inactivated upon chemical immobilization on a nanoparticle template and activated in response to a chemical stimulus. The activation rate of each drug payload is controlled using a biologically inert bioorthogonal chemistry approach. By exploiting the subtle differences in the 'click-to-release' bioorthogonal reaction, we engineered a single delivery platform capable of releasing the payloads in a time-staggered manner in response to a single dose of a highly specific, yet reactive, small molecule. Incorporation of both di-axial, 'fast release', and di-equatorial, 'slow release', TCO linkers into our nanodrug assembly inhibited the activity of the drug molecules and enabled us to control the timing and activation of each payload. This single-trigger dual-responsive nanoparticle construct and its release kinetics were characterized using two molecular fluorescent probes and tested in vitro for efficient delivery of molecular payloads. In this manuscript we show that this approach was also successful in the treatment of triple negative BT-20 breast cancer cells. Our nanodrug loaded with the slow-releasing doxorubicin and fast-releasing PAC-1 prodrugs displayed a greater therapeutic response than the nanodrug which released both payloads simultaneously.

Click activated protodrugs against cancer increase the therapeutic potential of chemotherapy through local capture and activation

“…Structural elements of TCO were explored to introduce additional hydrophilic groups, as illustrated in Scheme 1. At the core of the protodrug structures is a heterobifunctional TCO [36][37] bearing a carboxylic acid at a tertiary carbon, which was regioselectively modified with cytotoxic compounds on one end and functionalized with hydrophilic groups, such as glycine or aspartic acid on the other. Importantly, the TCO carboxylate used is 99% enantiomeric excess (ee) at that tertiary chiral carbon, so that only single diastereomers of the protodrugs are formed.…”

Switchable Fluorescence of Doxorubicin for Label‐Free Imaging of Bioorthogonal Drug Release

“…Dox‐TCO‐NHS is a small molecule prodrug which is synthesized for the assembly of a Dox nanodrug formulation (Scheme and Scheme S1 in the Supporting Information). The attached Dox can be released from nanodrug assembly through bond‐cleaving bioorthogonal chemistry in response to tetrazine . We have previously demonstrated that toxicity of Dox‐TCO (IC 50 =98 nM for Dox‐TCO) increases fivefold after its reaction with tetrazine uncaging unmodified doxorubicin (IC 50 =480 nM for Dox) .…”

“…The Dox is first derivatized with NHS‐TCO‐NHS which is necessary for its subsequent attachment to NP surface for click‐to‐release studies. This derivatization offers several useful features; that is, 1) cytotoxicity is decreased with TCO modification, 2) resistance to release in response to endogenous factors and, 3) Dox release specific to its nontoxic chemical partner …”

“…CH 2 Cl 2 (3×100 mL) was used to extract the product which was dried with Na 2 SO 4 . The final product was obtained by chromatography using 1 % Et 2 O in pentane (1.2 g, 72 %) . 1 H NMR (CDCl 3 , 400 MHz) δ: 3.62 (sep, J =6.8 Hz , 2H), 1.51 (d, J =6.9 Hz , 12H); 13 C NMR (CDCl 3 , 100 MHz) δ: 173.69, 34.14, 21.22; HRMS (DART) m/z : calcd.…”

Activation and Delivery of Tetrazine-Responsive Bioorthogonal Prodrugs

“…In addition, the drug can be administered more selectively under imaging guidance. Several studies have substantiated the crucial role of nanomaterials for diagnosis and imaging based on tetrazine-responsive bioorthogonal cleavage [108][109][110][111]. For example, a vinyl ether-caged camptothecin prodrug and tetrazine-quenched near-infrared fluorophore were separately encapsulated into liposomes, which localized to tumors due to the EPR effect [112].…”