Bio-Responsive Macromolecular Drug and Small-Molecular Drug Conjugates: Nanoparticulate Prodrugs for Tumor Microenvironment Heterogeneity Management and Therapeutic Response Enhancement

Iterative Design Reveals Molecular Domain Relationships in Supramolecular Peptide-Drug Conjugates

Supramolecular peptide-drug conjugates (sPDCs) are prepared by covalent attachment of a drug moiety to a peptide motif programmed for one-dimensional self-assembly, with subsequent physical entanglement of these fibrillar structures enabling formation of nanofibrous hydrogels. This class of prodrug materials presents an attractive platform for mass-efficient and site-specific delivery of therapeutic agents using a discrete, single-component molecular design. However, a continued challenge in sPDC development is elucidating relationships between supramolecular interactions in their drug and peptide domains and the resultant impacts of these domains on assembly outcomes and material properties. Inclusion of a saturated alkyl segment alongside the prodrug in the hydrophobic domain of sPDCs could relieve some of the necessity for ordered, prodrug-produg interactions. Accordingly, nine sPDCs are prepared here to iterate the design variables of amino acid sequence and hydrophobic prodrug-alkyl block design. All molecules spontaneously formed hydrogels under physiological conditions, indicating a less hindered thermodynamic path to self-assembly relative to previous prodrug-only designs. However, material studies on the supramolecular arrangement, formation, and mechanical properties of the resultant sPDC hydrogels as well as their drug release profiles showed complex relationships between the hydrophobic and peptide domains in the formation and function of the resulting assemblies. Together, these results indicate that sPDC material properties are intrinsically linked to holistic molecular design with coupled contributions from their prodrug and peptide domains in directing properties of the emergent materials.

A Targeted and Responsive Nanoprodrug Delivery System for Synergistic Glioma Chemotherapy

Doxorubicin (DOX) is widely used as a chemotherapeutic agent for both hematologic and solid tumors and is a reasonable candidate for glioma treatment. However, its effectiveness is hindered by significant toxicity and drug resistance. Moreover, the presence of the blood-brain barrier (BBB) brings a crucial challenge to glioma therapy. In response, a GSH-responsive and actively targeted nanoprodrug delivery system (cRGD/PSDOX-Cur@NPs) are developed. In this system, a disulfide bond-bridged DOX prodrug (PEG-SS-DOX) is designed to release specifically in the high glutathione (GSH) tumor environment, markedly reducing the cardiotoxicity associated with DOX. To further address DOX resistance, curcumin, serving as a P-glycoprotein (P-gp) inhibitor, effectively increased cellular DOX concentration. Consequently, cRGD/PSDOX-Cur@NPs exhibited synergistic anti-tumor effects in vitro. Furthermore, in vivo experiments validated the superior BBB penetration and brain-targeting abilities of cRGD/PSDOX-Cur@NPs, showcasing the remarkable potential for treating both subcutaneous and orthotopic gliomas. This research underscores that this nanoprodrug delivery system presents a novel approach to inhibiting glioma while addressing resistance and systemic toxicity.

Systemic Administration with Bacteria-Inspired Nanosystems for Targeted Oncolytic Therapy and Antitumor Immunomodulation

Malignant tumors represent a formidable global health challenge, compelling the pursuit of innovative treatment modalities. Oncolytic therapy has emerged as a promising frontier in antitumor strategies. However, both natural agents (such as oncolytic bacteria or viruses) and synthetic oncolytic peptides confront formidable obstacles in clinical trials, which include the delicate equilibrium between safety and efficacy, the imperative for systemic administration with targeted therapy, and the need to counteract oncolysis-induced immunosuppression. To overcome these dilemmas, we have developed biomimetic nanoengineering to create oncolytic bacteria-inspired nanosystems (OBNs), spanning from hierarchical structural biomimicry to advanced bioactive biomimicry. Our OBNs harbor inherent oncolytic potential, including functionalized oligosaccharides mimicking bacterial cell walls for optimal blood circulation and tumor targeting, tumor acidity-switchable decoration for tumor-specific oncolysis, stereospecific tryptophan-rich peptides for robust oncolytic activity, encapsulated tumor immunomodulators for enhanced immunotherapy, and innate multimodal imaging potential for biological tracing. This work elucidates the efficacy and mechanisms of OBNs, encompassing primary tumor suppression, metastasis prevention, and recurrence inhibition. Systemic administration of d-chiral OBNs has demonstrated superior oncolytic efficacy, surpassing intratumoral injections of clinical-grade oncolytic peptides. This work heralds an era in biomimetic engineering on oncolytic agents, promising the revolutionization of contemporary oncolytic therapy paradigms for clinical translation.