The programmed site-specific delivery of LY3200882 and PD-L1 siRNA boosts immunotherapy for triple-negative breast cancer by remodeling tumor microenvironment.

Despite the remarkable success of immunotherapies over the past decade, their effectiveness against triple-negative breast cancer (TNBC) is limited to a small subset of patients, mainly due to the low immunogenicity and unfavorable tumor microenvironment. In this study, we successfully constructed a programmed site-specific delivery nanosystem for the combined delivery of transforming growth factor beta (TGF-ß) receptor inhibitor LY3200882 (LY) and PD-L1 siRNA (siPD-L1) to boost anti-tumor immunotherapy. As expected, LY in the outer layer of the nanosystem was released by stimulation of MMP2, and dramatically down-regulated the expression of extracellular matrix (ECM) in the tumor-associated fibroblasts (TAFs), and thus promoted the infiltration of effector T cells and penetration of nanomedicines. Simultaneously, the blockade of TGF-ß by LY also triggered immunogenic cell death (ICD) of tumor cells and induced the maturation of dendritic cells. Moreover, the programmed design provided the siPD-L1/protamine cationic inner core with easier access to tumor cells and TAFs after MMP2-stimulated breakup of the outer layer, down-regulating the expression of PD-L1 in both types of cells. Notably, the synergistic effect of LY and siPD-L1 remarkably enhanced the tumor antigen presentation and immunosuppressive microenvironment remodeling, thus efficiently inhibiting the TNBC growth, metastasis, and recurrence. Therefore, the programmed site-specific delivery nanosystem is a promising drug delivery platform for boosting anti-tumor immunotherapy efficacy for TNBC.

Hypoxia-Sensitive Zwitterionic Vehicle for Tumor-Specific Drug Delivery through Antifouling-Based Stable Biotransport Alongside PDT-Sensitized Controlled Release.

A hypoxia-sensitive zwitterionic vehicle, DHigh-PEI-(A+P), with the ability for antifouling-mediated, stable biotransport and a photodynamic therapy (PDT)-sensitized hypoxic response for spatiotemporal controlled drug release, was developed for the tumor-specific delivery of chemotherapeutics and biomacromolecules. The amphiphilic DHigh-PEI-(A+P) was constructed from a betaine monomer (DMAAPS), a photosensitizer (PpIX), and an azobenzene-4,4'-dicarboxylic acid-modified polyethylenimine. Herein paclitaxel (PTX) was selected as a common model drug to verify the functions of the designed polymer. First, DHigh-PEI-(A+P) was demonstrated to spontaneously coassemble with PTX in aqueous solution with high drug loading (>35%). The desirable antifouling ability of DHigh-PEI-(A+P) was independently verified by efficient 4T1 endocytosis in serum alongside systemic tumor targeting. Furthermore, PpIX-mediated PDT was verified to aggravate and homogenize a hypoxic microenvironment at the cell and tissue levels for a sharp responsive disassembly of DHigh-PEI-(A+P) and thus a robust drug release in a well-controlled manner. As a result, DHigh-PEI-(A+P) amplified the therapeutic outcome of PTX on orthotopic 4T1 mouse models with minimal collateral damage. We proposed that DHigh-PEI-(A+P) may serve as a tailor-designed universal vehicle for the tumor-specific delivery of drugs with distinct physicochemical properties.

Biomineralization-inspired dasatinib nanodrug with sequential infiltration for effective solid tumor treatment.

The complex blood environment, heterogenic enhanced permeability and retention (EPR) effect, and dense matrix comprise the primary "leakage obstacles" impeding specific accumulation and penetration of nanodrugs against solid tumors, thus forming a key bottleneck for their clinical application. Herein, we present a biomineralization-inspired dasatinib (DAS) nanodrug (CIPHD/DAS) that sequentially permeates all of the abovementioned hindrances for efficient treatment of solid tumors. CIPHD/DAS exhibited a robust hybrid structure constructed from an iRGD-modified hyaluronic acid-deoxycholic acid organic core and a calcium phosphate mineral shell. In vitro and in vivo data demonstrated the mechanism of sequential tumoral infiltration was based on mineral-stiffened blood circulation with decreased premature drug leakage, iRGD-endowed tumor-specific transendothelial transport for "first-order promotion of accumulation" and DAS-mediated restoration of fibrotic stromal homeostasis for "second-order promotion of penetration". Resultantly, CIPHD/DAS showed remarkable distal drug availability in desmoplastic 4T1/CAFs orthotropic mouse models and significantly suppressed tumor growth and metastasis. This optimized strategy with sequential permeabilization of the capital "leakage obstacles" validates a promising paradigm to conquer the "impaired delivery and penetration" associated bottleneck of nanodrugs in the clinical treatment of solid tumors.

Free Adriamycin-Loaded pH/Reduction Dual-Responsive Hyaluronic Acid-Adriamycin Prodrug Micelles for Efficient Cancer Therapy.

Currently, tumor-targeted nanocarriers self-assembled from amphiphilic polymer-drug conjugates are of great demand. The appeal of these carriers arises mainly through their excellent loading efficiency of homologous drug molecules with microenvironment-triggered drug release. Herein, doxorubicin (DOX) was constructed to a hyaluronic acid (HA) backbone through hydrazone and disulfide linkages to construct pH and reduction coresponsive prodrug conjugates (HA-ss-DOX). During formulation, the amphipathic HA-ss-DOX spontaneously assembled into distinct core/shell micelles in aqueous media and showed conspicuous physical DOX loading capabilities (29.1%, DOX/HA-ss-DOX) based on homologous compatibility. DOX/HA-ss-DOX micelles were shown to be stable in normal physiological environments, while accomplishing selective, rapid DOX release at acidic pH and/or highly reducing conditions. The efficacy of DOX/HA-ss-DOX micelles was tested on A549 human lung cancer cells, wherein flow cytometry and confocal microscopy analysis revealed their HA receptor-mediated endocytosis mechanism. In comparison, DOX-loaded redox-insensitive micelles (DOX/HA-DOX) still demonstrated pH-dependent drug release. However, a more rapid intracellular DOX release profile was achieved in DOX/HA-ss-DOX micelles because of their sensitivity to both acidic and reducing environments. Resultantly, DOX/HA-ss-DOX exhibited the strongest cytotoxicity and apoptosis-inducing ability among all tested groups when tested on an A549 cell line and xenograft model.