Glioma Dual-Targeting Nanohybrid Protein Toxin Constructed by Intein-Mediated Site-Specific Ligation for Multistage Booster Delivery

Abstract

Malignant glioma is one of the most untreatable cancers because of the formidable blood-brain barrier (BBB), through which few therapeutics can penetrate and reach the tumors. Biologics have been booming in cancer therapy in the past two decades, but their application in brain tumor has long been ignored due to the impermeable nature of BBB against effective delivery of biologics. Indeed, it is a long unsolved problem for brain delivery of macromolecular drugs, which becomes the Holy Grail in medical and pharmaceutical sciences. Even assisting by targeting ligands, protein brain delivery still remains challenging because of the synthesis difficulties of ligand-modified proteins. Herein, we propose a rocket-like, multistage booster delivery system of a protein toxin, trichosanthin (TCS), for antiglioma treatment. TCS is a ribosome-inactivating protein with the potent activity against various solid tumors but lack of specific action and cell penetration ability. To overcome the challenge of its poor druggability and site-specific modification, intein-mediated ligation was applied, by which a gelatinase-cleavable peptide and cell-penetrating peptide (CPP)-fused recombinant TCS toxin can be site-specifically conjugated to lactoferrin (LF), thus constructing a BBB-penetrating, gelatinase-activatable cell-penetrating nanohybrid TCS toxin. This nanohybrid TCS system is featured by the multistage booster strategy for glioma dual-targeting delivery. First, LF can target to the BBB-overexpressing low-density lipoprotein receptor-related protein-1 (LRP-1), and assist with BBB penetration. Second, once reaching the tumor site, the gelatinase-cleavable peptide acts as a separator responsive to the glioma-associated matrix metalloproteinases (MMPs), thus releasing to the CPP-fused toxin. Third, CPP mediates intratumoral and intracellular penetration of TCS toxin, thereby enhancing its antitumor activity. The BBB penetration and MMP-2-activability of this delivery system were demonstrated. The antiglioma activity was evaluated in the subcutaneous and orthotopic animal models. Our work provides a useful protocol for improving the druggability of such class of protein toxins and promoting their in-vivo application for targeted cancer therapy.

Protease-triggered bioresponsive drug delivery for the targeted theranostics of malignancy

“…In addition, many other chemotherapeutics-derived nanoDDS, for example gemcitabine (GEM) 77 , 78 , coumarin 6 27 , trichosanthin 79 , methotrexate (MTX) 80 , pirfenidone 81 , pirarubicin 82 , cabazitaxel 83 , and SN38 84 , have also made extensive biomedical advances as stand-alone or multidrug combinations.…”

“…DOX-encapsulated gold nanoclusters were presented for computed tomography (CT) imaging-visualized cancer chemotherapy 123 . The above MMP-2-encouraged representative achievements in cancer theranostics are summarized in Table 2 23 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 ...…”

Genetically-engineered “all-in-one” vaccine platform for cancer immunotherapy

“…The primary anticancer mechanism of TCS is its ribosome-inactivating effect. We have demonstrated its anticancer potential in various tumor models including fibrosarcoma, glioma, and drug-resistant lung tumor 4 , 5 , 6 . However, the native TCS is hardly clinically serviceable as an i.v.…”

Hypoxia-responsive lipid-poly-(hypoxic radiosensitized polyprodrug) nanoparticles for glioma chemo- and radiotherapy

“…Nanocarriers, which have been considered to be emerging vehicles in the field of cancer therapy, can overcome these obstacles 23 , 24 . Nanocarriers were designed to overcome hurdles such as the side effects of chemotherapy drugs, to increase the intratumor concentration of the drug and to achieve glioma targeting 25 . Various nanocarriers have been designed to deliver drugs for cancer-targeted therapy, such as liposomes 26 - 28 , micelles 29 and polymersomes 30 , 31 .…”