Lipid-Based Intelligent Vehicle Capabilitized with Physical and Physiological Activation

Reliable high-PAP-1-loaded polymeric micelles for cancer therapy: preparation, characterization, and evaluation of anti-tumor efficacy

The mitochondrial potassium channel Kv1.3 is a critical therapeutic target, as its blockade induces cancer cell apoptosis, highlighting its therapeutic potential. PAP-1, a potent and selective membrane-permeant Kv1.3 inhibitor, faces solubility challenges affecting its bioavailability and antitumor efficacy. To circumvent these challenges, we developed a tumor-targeting drug delivery system by encapsulating PAP-1 within pH-responsive mPEG-PAE polymeric micelles. These self-assembled micelles exhibited high entrapment efficiency (91.35%) and drug loading level (8.30%). As pH decreased, the micelles exhibited a significant increase in particle size and zeta potential, accompanied by a surge in PAP-1 release. Molecular simulations revealed that PAE's tertiary amine protonation affected the self-assembly process, modifying hydrophobicity and resulting in larger, loosely packed particles. Furthermore, compared to free PAP-1 or PAP-1 combined with MDR inhibitors, PAP-1-loaded micelles significantly enhanced cytotoxicity and apoptosis induction in Jurkat and B16F10 cells, through mechanisms involving decreased mitochondrial membrane potential and elevated caspase-3 activity. In vivo, while free PAP-1 failed to reduce tumor size in a B16F10 melanoma mouse model, PAP-1-loaded micelles substantially suppressed tumors, reducing volume by up to 94.26%. Fluorescent-marked micelles effectively accumulated in mouse tumors, confirming their targeting efficiency. This strategy holds promise for significantly improving PAP-1's antitumor efficacy in tumor therapy.

Oral delivery of therapeutic proteins by engineered bacterial type zero secretion system

Genetically engineered commensal bacteria are promising living drugs, however, their therapeutic molecules are frequently confined to their colonization sites. Herein, we report an oral protein delivery technology utilizing an engineered bacterial type zero secretion system (T0SS) via outer membrane vesicles (OMVs). We find that OMVs produced in situ by Escherichia coli Nissle 1917 (EcN) can penetrate the intact gut epithelial barrier to enter the circulation and that epithelial transcytosis involves pinocytosis and dynamin-dependent pathways. EcN is engineered to endogenously load various enzymes into OMVs, and the secreted enzyme-loaded OMVs are able to stably catalyze diverse detoxification reactions against digestive fluid and even enter the circulation. Using hyperuricemic mice and uricase delivery as a demonstration, we demonstrate that the therapeutic efficacy of our engineered EcN with a modified T0SS outperforms that with a direct protein secretion apparatus. The enzyme-loaded OMVs also effectively detoxify human serum samples, highlighting the potential for the clinical treatment of metabolic disorders.

Capturing the dynamic integrity of carbocyanine fluorophore-based lipid nanoparticles using the FRET technique

Nanoparticles capable of dynamically reporting their structural integrity in real-time are a powerful tool to guide the design of drug delivery technologies. Lipid nanoparticles (LNPs) offer multiple important advantages for drug delivery, including stability, protection of active substances, and sustained release capabilities. However, tracking their structural integrity and dynamic behaviour in complex biological environments remains challenging. Here, we report the development of a Förster resonance energy transfer (FRET)-enabled LNP platform that achieves unprecedented sensitivity and precision in monitoring nanoparticle disintegration. The FRET-based LNPs were prepared using nanoprecipitation, encapsulating high levels of 3,3'-dioctadecyloxacarbocyanine perchlorate (DiO) and 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) fluorophores as the donor and acceptors, respectively. The resulting LNPs had a mean diameter of 114 ± 19 nm with a distinct FRET signal. An optimal energy transfer efficiency of 0.98 and an emission quantum yield of 0.13 were achieved at 11.1% fluorophore loading in the LNPs, balancing efficient energy transfer and minimal aggregation-induced quenching. Using the FRET reporting, three dissociation stages of FRET LNPs were observed: solvation, indicated by an increased emission intensity; swelling and partial dissolution, evidenced by changes in emission maxima and mean size; and complete dissociation, confirmed by emission solely from DiO and the absence of particles. Testing the nanoparticles in live cells (telomerase-immortalised human corneal epithelial cells, hTCEpi cells) revealed a direct link to the disappearance of the FRET signal with the dissociation of FRET NPs. The nanoparticles initially exhibited a strong extracellular FRET signal, which diminished after cellular internalisation. This suggests that the LNPs disintegrate after entering the cells. These findings establish FRET-based LNPs as a robust tool for real-time nanoparticle tracking, offering insights into their integrity and release mechanisms, with potential applications in advanced drug delivery and diagnostics.

Thermal and Magnetic Dual-Responsive Catheter-Assisted Shape Memory Microrobots for Multistage Vascular Embolization

Catheters navigating through complex vessels, such as sharp turns or multiple U-turns, remain challenging for vascular embolization. Here, we propose a novel multistage vascular embolization strategy for hard-to-reach vessels that releases untethered swimming shape-memory magnetic microrobots (SMMs) from the prior catheter to the vessel bifurcation. SMMs, made of organo-gel with magnetic particles, ensure biocompatibility, radiopacity, thrombosis, and fast thermal and magnetic responses. An SMM is initially a linear shape with a 0.5-mm diameter at 20 °C inserted in a catheter. It transforms into a predetermined helix within 2 s at 38 °C blood temperature after being pushed out of the catheter into the blood. SMMs enable agile swimming in confined and tortuous vessels and can swim upstream using helical propulsion with rotating magnetic fields. Moreover, we validated this multistage vascular embolization in living rabbits, completing 100-cm travel and renal artery embolization in 2 min. After 4 weeks, the SMMs maintained the embolic position, and the kidney volume decreased by 36%.

Progesterone receptor potentiates macropinocytosis through CDC42 in pancreatic ductal adenocarcinoma

Endocrine receptors play an essential role in tumor metabolic reprogramming and represent a promising therapeutic avenue in pancreatic ductal adenocarcinoma (PDAC). PDAC is characterized by a nutrient-deprived microenvironment. To meet their ascendant energy demands, cancer cells can internalize extracellular proteins via macropinocytosis. However, the roles of endocrine receptors in macropinocytosis are not clear. In this study, we found that progesterone receptor (PGR), a steroid-responsive nuclear receptor, is highly expressed in PDAC tissues obtained from both patients and transgenic LSL-KrasG12D/+; LSL-Trp53R172H/+; PDX1-cre (KPC) mice. Moreover, PGR knockdown restrained PDAC cell survival and tumor growth both in vitro and in vivo. Genetic and pharmacological PGR inhibition resulted in a marked attenuation of macropinocytosis in PDAC cells and subcutaneous tumor models, indicating the involvement of this receptor in macropinocytosis regulation. Mechanistically, PGR upregulated CDC42, a critical regulator in macropinocytosis, through PGR-mediated transcriptional activation. These data deepen the understanding of how the endocrine system influences tumor progression via a non-classical pathway and provide a novel therapeutic option for patients with PDAC.