Glycooligomer-Functionalized Catalytic Nanocompartments Co-Loaded with Enzymes Support Parallel Reactions and Promote Cell Internalization.

A major shortcoming associated with the application of enzymes in drug synergism originates from the lack of site-specific, multifunctional nanomedicine. This study introduces catalytic nanocompartments (CNCs) made of a mixture of PDMS-b-PMOXA diblock copolymers, decorated with glycooligomer tethers comprising eight mannose-containing repeating units and coencapsulating two enzymes, providing multifunctionality by their in situ parallel reactions. Beta-glucuronidase (GUS) serves for local reactivation of the drug hymecromone, while glucose oxidase (GOx) induces cell starvation through glucose depletion and generation of the cytotoxic H2O2. The insertion of the pore-forming peptide, melittin, facilitates diffusion of substrates and products through the membranes. Increased cell-specific internalization of the CNCs results in a substantial decrease in HepG2 cell viability after 24 h, attributed to simultaneous production of hymecromone and H2O2. Such parallel enzymatic reactions taking place in nanocompartments pave the way to achieve efficient combinatorial cancer therapy by enabling localized drug production along with reactive oxygen species (ROS) elevation.

Nanoassemblies designed for efficient nuclear targeting.

One of the key aspects of coping efficiently with complex pathological conditions is delivering the desired therapeutic compounds with precision in both space and time. Therefore, the focus on nuclear-targeted delivery systems has emerged as a promising strategy with high potential, particularly in gene therapy and cancer treatment. Here, we explore the design of supramolecular nanoassemblies as vehicles to deliver specific compounds to the nucleus, with the special focus on polymer and peptide-based carriers that expose nuclear localization signals. Such nanoassemblies aim at maximizing the concentration of genetic and therapeutic agents within the nucleus, thereby optimizing treatment outcomes while minimizing off-target effects. A complex scenario of conditions, including cellular uptake, endosomal escape, and nuclear translocation, requires fine tuning of the nanocarriers' properties. First, we introduce the principles of nuclear import and the role of nuclear pore complexes that reveal strategies for targeting nanosystems to the nucleus. Then, we provide an overview of cargoes that rely on nuclear localization for optimal activity as their integrity and accumulation are crucial parameters to consider when designing a suitable delivery system. Considering that they are in their early stages of research, we present various cargo-loaded peptide- and polymer nanoassemblies that promote nuclear targeting, emphasizing their potential to enhance therapeutic response. Finally, we briefly discuss further advancements for more precise and effective nuclear delivery.

Peptide nanocarriers co-delivering an antisense oligonucleotide and photosensitizer elicit synergistic cytotoxicity.

Combination therapies demand co-delivery platforms with efficient entrapment of distinct payloads and specific delivery to cells and possibly organelles. Herein, we introduce the combination of two therapeutic modalities, gene and photodynamic therapy, in a purely peptidic platform. The simultaneous formation and cargo loading of the multi-micellar platform is governed by self-assembly at the nanoscale. The multi-micellar architecture of the nanocarrier and the positive charge of its constituent micelles offer controlled dual loading capacity with distinct locations for a hydrophobic photosensitizer (PS) and negatively charged antisense oligonucleotides (ASOs). Moreover, the nuclear localization signal (NLS) sequence built-in the peptide targets PS + ASO-loaded nanocarriers to the nucleus. Breast cancer cells treated with nanocarriers demonstrated photo-triggered enhancement of radical oxygen species (ROS) associated with increased cell death. Besides, delivery of ASO payloads resulted in up to 90 % knockdown of Bcl-2, an inhibitor of apoptosis that is overexpressed in more than half of all human cancers. Simultaneous delivery of PS and ASO elicited synergistic apoptosis to an extent that could not be reached by singly loaded nanocarriers or the free form of the drugs. Both, the distinct location of loaded compounds that prevents them from interfering with each other, and the highly efficient cellular delivery support the great potential of this versatile peptide platform in combination therapy.

FAP Targeting of Photosensitizer-Loaded Polymersomes for Increased Light-Activated Cell Killing.

As current chemo- and photodynamic cancer therapies are associated with severe side effects due to a lack of specificity and to systemic toxicity, innovative solutions in terms of targeting and controlled functionality are in high demand. Here, we present the development of a polymersome nanocarrier equipped with targeting molecules and loaded with photosensitizers for efficient uptake and light-activated cell killing. Polymersomes were self-assembled in the presence of photosensitizers from a mixture of nonfunctionalized and functionalized PDMS-b-PMOXA diblock copolymers, the latter designed for coupling with targeting ligands. By encapsulation inside the polymersomes, the photosensitizer Rose Bengal was protected, and its uptake into cells was mediated by the nanocarrier. Inhibitor of fibroblast activation protein α (FAPi), a ligand for FAP, was attached to the polymersomes' surface and improved their uptake in MCF-7 breast cancer cells expressing relatively high levels of FAP on their surface. Once internalized by MCF-7, irradiation of Rose Bengal-loaded FAPi-polymersomes generated reactive oxygen species at levels high enough to induce cell death. By combining photosensitizer encapsulation and specific targeting, polymersomes represent ideal candidates as therapeutic nanocarriers in cancer treatment.

A self-assembling peptidic platform to boost the cellular uptake and nuclear delivery of oligonucleotides.

The design of non-viral vectors that efficiently deliver genetic materials into cells, in particular to the nucleus, remains a major challenge in gene therapy and vaccine development. To tackle the problems associated with cellular uptake and nuclear targeting, here we introduce a delivery platform based on the self-assembly of an amphiphilic peptide carrying an N-terminal KRKR sequence that functions as a nuclear localization signal (NLS). By means of a single-step self-assembly process, the amphiphilic peptides afford the generation of NLS-functionalized multicompartment micellar nanostructures that can embed various oligonucleotides between their individual compartments. Detailed physicochemical, cellular and ultrastructural analyses demonstrated that integrating an NLS in the hydrophilic domain of the peptide along with tuning its hydrophobic domain led to self-assembled DNA-loaded multicompartment micelles (MCMs) with enhanced cellular uptake and nuclear translocation. We showed that the nuclear targeting ensued via the NLS interaction with the nuclear transport receptors of the karyopherin family. Importantly, we observed that the treatment of MCF-7 cells with NLS-MCMs loaded with anti-BCL2 antisense oligonucleotides resulted in up to 86% knockdown of BCL2, an inhibitor of apoptosis that is overexpressed in more than half of all human cancers. We envision that this platform can be used to efficiently entrap and deliver diverse genetic payloads to the nucleus and find applications in basic research and biomedicine.

Peptide-Assisted Nucleic Acid Delivery Systems on the Rise.

Concerns associated with nanocarriers' therapeutic efficacy and side effects have led to the development of strategies to advance them into targeted and responsive delivery systems. Owing to their bioactivity and biocompatibility, peptides play a key role in these strategies and, thus, have been extensively studied in nanomedicine. Peptide-based nanocarriers, in particular, have burgeoned with advances in purely peptidic structures and in combinations of peptides, both native and modified, with polymers, lipids, and inorganic nanoparticles. In this review, we summarize advances on peptides promoting gene delivery systems. The efficacy of nucleic acid therapies largely depends on cell internalization and the delivery to subcellular organelles. Hence, the review focuses on nanocarriers where peptides are pivotal in ferrying nucleic acids to their site of action, with a special emphasis on peptides that assist anionic, water-soluble nucleic acids in crossing the membrane barriers they encounter on their way to efficient function. In a second part, we address how peptides advance nanoassembly delivery tools, such that they navigate delivery barriers and release their nucleic acid cargo at specific sites in a controlled fashion.

Intercalation of curcumin into liposomal chemotherapeutic agent augments apoptosis in breast cancer cells.

Resistance to common chemotherapeutic agents is a frequent phenomenon in late-stage breast cancers. An ideal system capable of the co-delivery of hydrophobic and hydrophilic chemotherapeutic agents can regulate the dosage and co-localization of pharmaceutical compounds and thereby improve the anticancer efficacy. Here, for the first time, we have intercalated curcumin (Cur) into a double-layered membrane of cisplatin (Cis) liposomes to obtain a dosage controlled co-delivery formulation, capable of inducing apoptosis in breast cancer cells. The concentrations of Cur and Cis in nanoliposome (Cur-Cis@NLP) were optimized by response surface methodology (RSM); RSM optimization showed 99.81 and 23.86% entrapment efficiency for Cur and Cis, respectively. TEM analysis demonstrated the fabrication of nanoparticles with average diameter of 100 nm. The anticancer and apoptotic effects of Cur-Cis@NLPs were also evaluated using MTT assay, fluorescent staining and flow cytometry assays. Cytotoxicity assessments of various Cur-Cis@NLPs concentrations demonstrated a concentration-dependent manner. In comparison to free and liposomal Cis, Cur-Cis@NLP reduced breast cancer cells' viability (82.5%) in a significant manner at a final concentration of 32 µg.mL-1 and 20 µg.mL-1 of Cur and Cis, respectively. Combination index values calculation of Cur-Cis@NLP showed an overall CI value <1, indicating synergetic effect of the designed co-delivery system. Additionally, flow cytometry assay demonstrated Cur-Cis@NLPs triggered apoptosis about 10-folds higher than liposomal Cis. This co-drug delivery system has a potential for the encapsulation and release of both hydrophobic and hydrophilic drugs, while taking the advantages of the reduced cytotoxic effect along with achieving high potency.

Peptide-Based Nanoassemblies in Gene Therapy and Diagnosis: Paving the Way for Clinical Application.

Nanotechnology approaches play an important role in developing novel and efficient carriers for biomedical applications. Peptides are particularly appealing to generate such nanocarriers because they can be rationally designed to serve as building blocks for self-assembling nanoscale structures with great potential as therapeutic or diagnostic delivery vehicles. In this review, we describe peptide-based nanoassemblies and highlight features that make them particularly attractive for the delivery of nucleic acids to host cells or improve the specificity and sensitivity of probes in diagnostic imaging. We outline the current state in the design of peptides and peptide-conjugates and the paradigms of their self-assembly into well-defined nanostructures, as well as the co-assembly of nucleic acids to form less structured nanoparticles. Various recent examples of engineered peptides and peptide-conjugates promoting self-assembly and providing the structures with wanted functionalities are presented. The advantages of peptides are not only their biocompatibility and biodegradability, but the possibility of sheer limitless combinations and modifications of amino acid residues to induce the assembly of modular, multiplexed delivery systems. Moreover, functions that nature encoded in peptides, such as their ability to target molecular recognition sites, can be emulated repeatedly in nanoassemblies. Finally, we present recent examples where self-assembled peptide-based assemblies with "smart" activity are used in vivo. Gene delivery and diagnostic imaging in mouse tumor models exemplify the great potential of peptide nanoassemblies for future clinical applications.

A self-assembling amphiphilic peptide nanoparticle for the efficient entrapment of DNA cargoes up to 100 nucleotides in length.

To overcome the low efficiency and cytotoxicity associated with most non-viral DNA delivery systems we developed a purely peptidic self-assembling system that is able to entrap single- and double-stranded DNA of up to 100 nucleotides in length. (HR)3gT peptide design consists of a hydrophilic domain prone to undergo electrostatic interactions with DNA cargo, and a hydrophobic domain at a ratio that promotes the self-assembly into multi-compartment micellar nanoparticles (MCM-NPs). Self-assembled (HR)3gT MCM-NPs range between 100 to 180 nm which is conducive to a rapid and efficient uptake by cells. (HR)3gT MCM-NPs had no adverse effects on HeLa cell viability. In addition, they exhibit long-term structural stability at 4 °C but at 37 °C, the multi-micellar organization disassembles overtime which demonstrates their thermo-responsiveness. The comparison of (HR)3gT to a shorter, less charged H3gT peptide indicates that the additional arginine residues result in the incorporation of longer DNA segments, an improved DNA entrapment efficiency and an increase cellular uptake. Our unique non-viral system for DNA delivery sets the stage for developing amphiphilic peptide nanoparticles as candidates for future systemic gene delivery.

Liposome-targeted delivery for highly potent drugs.

Considerable adverse side effects and cytotoxicity of highly potent drugs for healthy tissue require the development of novel drug delivery systems to improve pharmacokinetics and result in selective distribution of the loaded agent. The introduction of targeted liposomal formulations has provided potential solutions for improved drug delivery to cancer cells, penetrating delivery through blood-brain barrier and gene therapy. A large number of investigations have been developed over the past few decades to overcome pharmacokinetics and unfavorable side effects limitations. These improvements have enabled targeted liposome to meet criteria for successful and improved potent drug targeting. Promising in vitro and in vivo results for liposomal-directed delivery systems appear to be effective for vast variety of highly potent therapeutics. This review will focus on the past decade's potential use and study of highly potent drugs using targeted liposomes.

Functionalized magnetic dextran-spermine nanocarriers for targeted delivery of doxorubicin to breast cancer cells.

In recent decades, targeted drug delivery systems for breast cancer treatment emerged as an ideal alternative and promising solution to reduce systemic side effects of chemotherapeutic agents. In this study, the preparation and characterization of cationic doxorubicin (DOX) loaded magnetic dextran-spermine (DEX-SP) nanocarriers (DEX-SP-DOX) by ionic gelation were fully investigated. Then, anti-HER2 as a monoclonal antibody (mAb) and targeting ligand was conjugated via EDC/NHS reagents. The binding was confirmed by Bradford assay and further assessments were carried out by size and zeta potential measurements. Cytotoxicity effect and internalization of magnetic nanocarriers were assessed by MTT and Prussian blue assays and transmission electron microscopy (TEM), respectively. DLS measurements indicated that the size of nanocarriers increased from 62 to 84 nm by conjugation of anti-HER2 to them. The in vitro release of DOX from mAb conjugated magnetic nanocarriers at pHs 5 and 7.4 was found to be 85 and 55.5%, respectively. The MTT and Prussian blue assays demonstrated enhanced and selective uptake of DEX-SP-DOX-mAb by SKBR cell (HER2 overexpressed cells) in comparison with unconjugated nanocarriers due to higher cellular binding. The TEM result also confirmed cellular internalization of DEX-SP-DOX-mAb magnetic nanocarriers. These results are very promising for targeted delivery of DOX to HER2 positive breast cancer cells.