Horseradish Peroxidase-Functionalized Gold Nanoconjugates for Breast Cancer Treatment Based on Enzyme Prodrug Therapy

Abstract

Introduction Breast cancer has the highest mortality rate among cancers in women. Patients suffering from certain breast cancers, such as triple-negative breast cancer (TNBC), lack effective treatments. This represents a clinical concern due to the associated poor prognosis and high mortality. As an approach to succeed over conventional therapy limitations, we present herein the design and evaluation of a novel nanodevice based on enzyme-functionalized gold nanoparticles to efficiently perform enzyme prodrug therapy (EPT) in breast cancer cells. Results In particular, the enzyme horseradish peroxidase (HRP) – which oxidizes the prodrug indole-3-acetic acid (IAA) to release toxic oxidative species – is incorporated on gold nanoconjugates (HRP-AuNCs), obtaining an efficient nanoplatform for EPT. The nanodevice is biocompatible and effectively internalized by breast cancer cell lines. Remarkably, co-treatment with HRP-AuNCs and IAA (HRP-AuNCs/IAA) reduces the viability of breast cancer cells below 5%. Interestingly, 3D tumor models (multicellular tumor spheroid-like cultures) co-treated with HRP-AuNCs/IAA exhibit a 74% reduction of cell viability, whereas the free formulated components (HRP, IAA) have no effect. Conclusion Altogether, our results demonstrate that the designed HRP-AuNCs nanoformulation shows a remarkable therapeutic performance. These findings might help to bypass the clinical limitations of current tumor enzyme therapies and advance towards the use of nanoformulations for EPT in breast cancer.

Advances of gold nanoclusters for bioimaging

“…Anti-human immunoglobulin E (IgE) is coupled to lipoic acid-modified fluorescent AuNCs to measure IgE in human serum ( Alonso et al., 2016 ). Horseradish peroxidase (HRP)-coupled AuNCs are internalized by breast cancer cells, generating free radicals and inducing apoptosis ( Vivo-Llorca et al., 2022 ).…”

Design of a gold nanoparticles site in an engineered lipase: an artificial metalloenzyme with enantioselective reductase-like activity

“…For this reason, such enzyme-Au bioconjugates are becoming increasingly important due to their wide range of applications in the field of nanomedicine such as diagnostic and sensing methods, photothermal therapy and administration and drug delivery among others. 19,20…”

“…For this reason, such enzyme-Au bioconjugates are becoming increasingly important due to their wide range of applications in the field of nanomedicine such as diagnostic and sensing methods, photothermal therapy and administration and drug delivery among others. 19,20 In fact, only a few works have been reported in the literature on design proteins for the sustainable synthesis of Au nanoclusters. 21,22 However, in all cases, very large nanoparticle sizes are obtained, and the presence of an external reducing agent is necessary for their formation.…”

Dual-Responsive Enzyme–Polysaccharide Conjugate as a Nanocarrier System for Enzyme Prodrug Therapy

“…It can activate non-toxic indole-3-acetic acid (IAA) and other indoles into various cytotoxic free radicals such as indolyl and peroxyl radicals via single-electron oxidation under hypoxia conditions found in most tumor cells. After the initial report by Folkes et al, the effectiveness of this peroxidase-catalyzed strategy has been repeatedly demonstrated in anticancer therapy. − Most reports utilize a gene-directed enzyme prodrug therapy requiring the need for delivery of the HRP gene and a successful expression in cells. ,,,, Only a few examples of the direct delivery of HRP enzymes are known. − For example, chitosan nanoparticles with encapsulated HRP have been shown to activate IAA in solution, which further causes the peroxidation of membrane lipids and DNA damage that eventually triggers cellular apoptosis . Similarly, porous metal–organic frameworks were loaded with HRP to activate IAA and induce cell death …”