Synergistic Enhancement of Lung Cancer Therapy Through Nanocarrier‐Mediated Sequential Delivery of Superantigen and Tyrosin Kinase Inhibitor

Gefitinib (GFT) and other tyrosine kinase inhibitors (TKIs) have been widely used for the treatment of advanced or metastatic lung cancer due to their reduced side effects when compared to classic cytotoxic chemotherapeutic agents. However, both intrinsic and acquired resistance often hinders the effectiveness of TKIs. Based on recent findings that the outcome of chemotherapy can be influenced by the host immune system at multiple levels, an exploration of whether activating antitumor immunity improves the efficacy of the targeted cancer therapy of TKIs is undertaken. To this end, a cationic carrier is used to deliver superantigen and GFT in a simultaneous or sequential manner. The sequential delivery of superantigen and GFT can significantly enhance T cell immunity, promote cytokine production, inhibit tumor growth, and prolong survival time in tumor models with lung carcinoma xenografts. Most importantly, dual sequential treatment reveals a synergistic effect on tumor inhibition, which is much more effective than the monotherapy of either GFT or pTSA, as well as the combined treatment through simultaneous codelivery of pTSA and GFT together. This study demonstrates the important contribution of immunotherapy to targeted molecular therapy and opens up new possibilities for treating a wide spectrum of cancers.     

Cell-Based Delivery Systems: Emerging Carriers for Immunotherapy

Immunotherapy is leading a paradigm shift in the treatment of various diseases, including tumors, auto-immune diseases, and infectious diseases. However, the limited response rate and systemic side effects significantly impede the clinical applications of immunotherapy. As natural carriers for proteins and molecules, cells with low immunogenicity and toxicity have attracted considerable attention for biomedical applications and have achieved encouraging progress especially in immunotherapy. The convergence of multiple disciplines has equipped cell-based delivery systems with control over their spatiotemporal distribution to enhance treatment efficacy and reduce side effects. Here, an overview of the fundamentals and design principles of cell-based delivery systems followed by a perspective that includes the most recent advances of various cells as delivery carriers, with a special focus on the implications of cell-based delivery systems for immunotherapy is offered.     

Optimizing the Size of Micellar Nanoparticles for Efficient siRNA Delivery

Delivery of small interfering RNA (siRNA) by nanocarriers has shown promising therapeutic potential in cancer therapy. However, poor understanding of the correlation between the physicochemical properties of nanocarriers and their interactions with biological systems has significantly hindered its anticancer efficacy. Herein, in order to identify the optimal size of nanocarriers for siRNA delivery, different sized cationic micellar nanoparticles (MNPs) (40, 90, 130, and 180 nm) are developed that exhibit similar siRNA binding efficacies, shapes, surface charges, and surface chemistries (PEGylation) to ensure size is the only variable. Size‐dependent biological effects are carefully and comprehensively evaluated through both in vitro and in vivo experiments. Among these nanocarriers, the 90 nm MNPs show the optimal balance of prolonged circulation and cellular uptake by tumor cells, which result in the highest retention in tumor cells. In contrast, larger MNPs are rapidly cleared from the circulation and smaller MNPs are inefficiently taken up by tumor cells. Accordingly, 90 nm MNPs carrying polo‐like kinase 1 (Plk1)‐specific siRNA (siPlk1) show superior antitumor efficacy, indicating that 90 nm could either be the optimal size for systemic delivery of siRNA or close to it. Our findings provide valuable information for rationally designing nanocarriers for siRNA‐based cancer therapy in the future.     

Remote‐Loaded Platelet Vesicles for Disease‐Targeted Delivery of Therapeutics

The recent emergence of biomimetic nanotechnology has facilitated the development of next‐generation nanodelivery systems capable of enhanced biointerfacing. In particular, the direct use of natural cell membranes can enable multivalent targeting functionalities. Herein, this study reports on the remote loading of small molecule therapeutics into cholesterol‐enriched platelet membrane‐derived vesicles for disease‐targeted delivery. Using this approach, high loading yields for two model drugs, doxorubicin and vancomycin, are achieved. Leveraging the surface markers found on platelet membranes, the resultant nanoformulations demonstrate natural affinity toward both breast cancer cells and methicillin‐resistant Staphylococcus aureus. In vivo, this translates to improved disease targeting, increasing the potency of the encapsulated drug payloads compared with free drugs and the corresponding nontargeted nanoformulations. Overall, this work demonstrates that the remote loading of drugs into functional platelet membrane‐derived vesicles is a facile means of fabricating targeted nanoformulations, an approach that can be easily generalized to other cell types in the future.     

Electrospun Fibrous Architectures for Drug Delivery,Tissue Engineering and Cancer Therapy

The versatile electrospinning technique is recognized as an efficient strategy to deliver active pharmaceutical ingredients and has gained tremendous progress in drug delivery, tissue engineering, cancer therapy, and disease diagnosis. Numerous drug delivery systems fabricated through electrospinning regarding the carrier compositions, drug incorporation techniques, release kinetics, and the subsequent therapeutic efficacy are presented herein. Targeting for distinct applications, the composition of drug carriers vary from natural/synthetic polymers/blends, inorganic materials, and even hybrids. Various drug incorporation approaches through electrospinning are thoroughly discussed with respect to the principles, benefits, and limitations. To meet the various requirements in actual sophisticated in vivo environments and to overcome the limitations of a single carrier system, feasible combinations of multiple drug‐inclusion processes via electrospinning could be employed to achieve programmed, multi‐staged, or stimuli‐triggered release of multiple drugs. The therapeutic efficacy of the designed electrospun drug‐eluting systems is further verified in multiple biomedical applications and is comprehensively overviewed, demonstrating promising potential to address a variety of clinical challenges.     

A Versatile Platform for the Tumor-Targeted Intracellular Delivery of Peptides,Proteins, and siRNA

The efficient delivery of biologics into cells provide unique opportunities to modulate intracellular targets not druggable by conventional small molecules. The supercharged polypeptide (SCP) has become a novel intracellular delivery system due to their special advantages, including enhanced delivery efficiency and serum tolerance. However, owing to their cationic charge and non-specificity characteristics, the in vivo application of SCP is limited. Here, an activatable SCP (ASCP) with a pH-sensitive charge shielding sequence (CSS), a protease cleavage site, and SCP are engineered. This system shows the potential to reduce the non-specific binding and effectively deliver various cargo (peptide, protein, small molecule, and siRNA) into the cytosol not only in vitro but also in vivo. Furthermore, an ASCP fusion protein is designed to co-delivery of peptide (KLA)/siRNA (IKBKE) with different tumorigenesis pathways to triple negative breast cancer (TNBC) for optimal therapeutic outcomes. It is believed that ASCP delivery system will facilitate the development of bioactive molecules for use against intracellular targets. This simple yet versatile delivery system can also pave the way for the co-delivery of multiple therapeutic cargos to address the emerging needs of combination cancer therapy.     

Inorganic Drug‐Delivery Nanovehicle Conjugated with Cancer‐Cell‐Specific Ligand

The surface of layered double hydroxide nanoparticles, a potential drug‐delivery nanovehicle, is modified with the cancer‐cell‐specific ligand, folic acid. The surface modification is successfully accomplished through step‐by‐step coupling reactions with aminopropyltriethoxysilane and 1‐ethyl‐3‐(3‐dimethyl aminopropyl)‐carbodiimide. In order to evaluate the cancer‐cell targeting effect of folic‐acid‐grafted layered double hydroxide utilizing fluorescence‐related assay, both layered double hydroxide with and without folic acid moiety are labeled with fluorescein 5′‐isothiocyanate. The uptake of layered double hydroxide and folic acid conjugated into KB and A549 cells is visualized using fluorescence microscopy and measured by flow cytometry. Both chemical and biological assay results demonstrate that the folic acid molecules are indeed conjugated to the surface of layered double hydroxide and thus the selectivity of nanovehicles to cancer cells overexpressing folate receptors increases. In this study, it is suggested that layered double hydroxide nanoparticles can be used as drug‐delivery carriers with a targeting function due to the chemical conjugation with specific ligand.     

Nanocarrier‐Mediated Cytosolic Delivery of Biopharmaceuticals

Biopharmaceuticals have emerged to play a vital role in disease treatment and have shown promise in the rapidly expanding pharmaceutical market due to their high specificity and potency. However, the delivery of these biologics is hindered by various physiological barriers, owing primarily to the poor cell membrane permeability, low stability, and increased size of biologic agents. Since many biological drugs are intended to function by interacting with intracellular targets, their delivery to intracellular targets is of high relevance. In this review, the authors summarize and discuss the use of nanocarriers for intracellular delivery of biopharmaceuticals via endosomal escape and, especially, the routes of direct cytosolic delivery by means including the caveolae‐mediated pathway, contact release, intermembrane transfer, membrane fusion, direct translocation, and membrane disruption. Strategies with high potential for translation are highlighted. Finally, the authors conclude with the clinical translation of promising carriers and future perspectives.     

Enzyme-Inspired Nanoreactor Containing Light-Controlled “Trojan Horse” for Redox-Hypersensitive Drug Delivery

The applications of bioresponsive materials are limited by the low levels of physiological triggers and spatiotemporal barriers in vivo. To address these issues, a light-controlled “Trojan horse” strategy is proposed by encapsulating a photo-caged reducing agent within reduction-responsive polymer vesicles. The polymersomes act as an enzyme-inspired nanoreactor for efficient photo-synthesis of dithiothreitol in situ, which attacks the disulfide bonds in polymer backbones and disintegrates the vehicles from the inside in a nanoconfined space. The assembly-catalyzed photoreduction reaction overcomes the temporal and spatial barriers for hyper-responsivity and enables ultrafast drug release even at 0.014 mm of dithiothreitol residues, a concentration 715 times lower than that required to cleave disulfide bonds. In addition, in both vitro and vivo, the equipment of upconverting nanoparticles and photothermal agents creates a near-infrared light-activated and self-heating nanoreactor, which allows for efficient intracellular drug delivery and excellent photo-chemo-immunotherapy of tumors. This work presents a new approach to designing smart materials and a promising platform for on-demand drug delivery applications.     

Dynamically Deformable Protein Delivery Strategy Disassembles Neutrophil Extracellular Traps to Prevent Liver Metastasis

Neutrophil extracellular traps (NETs), consisting of chromatin DNA filaments coated with granule proteins, promote metastasis by enhancing tumor cell migration to distant organs. Recent studies indicate that NETs adhere to cancer cell membranes and enhance cell motility significantly to induce liver metastasis in patients with breast and colon cancers. Herein, a dynamically deformable protein delivery strategy is developed to prevent liver metastasis by disassembling NETs. Specifically, poly amino acid conjugating with polyethylene glycol (PAAP) is explored and synthesized for DNase-1 delivery. Notably, PAAP/DNase-1 degrades chromatin to induce apoptosis, followed by cell membrane rupture and remaining DNase-1 releases to the extracellular. More importantly, the released DNase-1 disassembles NET-DNA to prevent liver metastasis induced by NET. In all, PAAP/DNase-1 treatment not only suppresses tumor growth by degrading intracellular chromatin, but also prevents the liver metastasis by disassembling the NET-NDA. This strategy may provide brand-new inspiration to prevent the liver metastasis fundamentally in patients with metastatic colon and breast cancer.     

A Facile Magnetic Extrusion Method for Preparing Endosome-Derived Vesicles for Cancer Drug Delivery

To date, the scaled-up manufacturing and efficient drug loading of exosomes are two existing challenges limiting the clinical translation of exosome-based drug delivery. Herein, a facile magnetic extrusion method is developed for preparing endosome-derived vesicles, also known as exosome mimetics (EMs), which share the same biological origin and similar morphology, composition, and biofunctions with native exosomes. The high yield and consistency of this magnetic extrusion method help to overcome the manufacturing bottleneck in exosome research. Moreover, the proposed standardized multi-step method readily facilitates the ammonium sulfate gradient approach to actively load chemodrugs such as doxorubicin into EMs. The engineered EMs developed and tested here exhibit comparable drug delivery properties as do native exosomes, and potently inhibit tumor growth by delivering doxorubicin in an orthotopic breast tumor model. These findings demonstrate that EMs can be prepared in a facile and scaled-up manner as a promising biological nanomedicine for cancer drug delivery.     

Gel–Liposome‐Mediated Co‐Delivery of Anticancer Membrane‐Associated Proteins and Small‐Molecule Drugs for Enhanced Therapeutic Efficacy

A programmed drug‐delivery system that can transport different anticancer therapeutics to their distinct targets holds vast promise for cancer treatment. Herein, a core–shell‐based “nanodepot” consisting of a liposomal core and a crosslinked‐gel shell (designated Gelipo) is developed for the sequential and site‐specific delivery (SSSD) of tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) and doxorubicin (Dox). As a small‐molecule drug intercalating the nuclear DNA, Dox is loaded in the aqueous core of the liposome, while TRAIL, acting on the death receptor (DR) on the plasma membrane, is encapsulated in the outer shell made of crosslinked hyaluronic acid (HA). The degradation of the HA shell by HAase that is concentrated in the tumor environment results in the rapid extracellular release of TRAIL and subsequent internalization of the liposomes. The parallel activity of TRAIL and Dox show synergistic anticancer efficacy. The half‐maximal inhibitory concentration (IC₅₀) of TRAIL and Dox co‐loaded Gelipo (TRAIL/Dox‐Gelipo) toward human breast cancer (MDA‐MB‐231) cells is 83 ng mL^–1 (Dox concentration), which presents a 5.9‐fold increase in the cytotoxicity compared to 569 ng mL^–1 of Dox‐loaded Gelipo (Dox‐Gelipo). Moreover, with the programmed choreography, Gelipo significantly improves the inhibition of the tumor growth in the MDA‐MB‐231 xenograft tumor animal model.