Nanoparticle-Mediated Multiple Modulation of Bone Microenvironment To Tackle Osteoarthritis.

Development of nanomedicines that can collaboratively scavenge reactive oxygen species (ROS) and inhibit inflammatory cytokines, along with osteogenesis promotion, is essential for efficient osteoarthritis (OA) treatment. Herein, we report the design of a ROS-responsive nanomedicine formulation based on fibronectin (FN)-coated polymer nanoparticles (NPs) loaded with azabisdimethylphoaphonate-terminated phosphorus dendrimers (G4-TBP). The constructed G4-TBP NPs-FN with a size of 268 nm are stable under physiological conditions, can be specifically taken up by macrophages through the FN-mediated targeting, and can be dissociated in the oxidative inflammatory microenvironment. The G4-TBP NPs-FN loaded with G4-TBP dendrimer having intrinsic anti-inflammatory property and FN having both anti-inflammatory and antioxidative properties display integrated functions of ROS scavenging, hypoxia attenuation, and macrophage M2 polarization, thus protecting macrophages from apoptosis and creating designed bone immune microenvironment for stem cell osteogenic differentiation. These characteristics of the G4-TBP NPs-FN lead to their effective treatment of an OA model in vivo to reduce pathological changes of joints including synovitis inhibition and cartilage matrix degradation and simultaneously promote osteogenic differentiation for bone repair. The developed nanomedicine formulation combining the advantages of both bioactive phosphorus dendrimers and FN to treat OA may be developed for immunomodulatory therapy of different inflammatory diseases.

Brain Delivery of Biomimetic Phosphorus Dendrimer/Antibody Nanocomplexes for Enhanced Glioma Immunotherapy via Immune Modulation of T Cells and Natural Killer Cells.

Fully mobilizing the activities of multiple immune cells is crucial to achieve the desired tumor immunotherapeutic efficacy yet still remains challenging. Herein, we report a nanomedicine formulation based on phosphorus dendrimer (termed AK128)/programmed cell death protein 1 antibody (aPD1) nanocomplexes (NCs) that are camouflaged with M1-type macrophage cell membranes (M1m) for enhanced immunotherapy of orthotopic glioma. The constructed AK128-aPD1@M1m NCs with a mean particle size of 160.3 nm possess good stability and cytocompatibility. By virtue of the decorated M1m having α4 and ß1 integrins, the NCs are able to penetrate the blood-brain barrier to codeliver both AK128 with intrinsic immunomodulatory activity and aPD1 to the orthotopic glioma with prolonged blood circulation time. We show that the phosphorus dendrimer AK128 can boost natural killer (NK) cell proliferation in peripheral blood mononuclear cells, while the delivered aPD1 enables immune checkpoint blockade (ICB) to restore the cytotoxic T cells and NK cells, thus promoting tumor cell apoptosis and simultaneously decreasing the tumor distribution of regulatory T cells vastly for improved glioma immunotherapy. The developed nanomedicine formulation with a simple composition achieves multiple modulations of immune cells by utilizing the immunomodulatory activity of nanocarrier and antibody-mediated ICB therapy, providing an effective strategy for cancer immunotherapy.

Unsymmetrical Low-Generation Cationic Phosphorus Dendrimers as a Nonviral Vector to Deliver MicroRNA for Breast Cancer Therapy.

The development of nonviral dendritic polymers with a simple molecular backbone and great gene delivery efficiency to effectively tackle cancer remains a great challenge. Phosphorus dendrimers or dendrons are promising vectors due to their structural uniformity, rigid molecular backbones, and tunable surface functionalities. Here, we report the development of a new low-generation unsymmetrical cationic phosphorus dendrimer bearing 5 pyrrolidinium groups and one amino group as a nonviral gene delivery vector. The created AB5-type dendrimers with simple molecular backbone can compress microRNA-30d (miR-30d) to form polyplexes with desired hydrodynamic sizes and surface potentials and can effectively transfect miR-30d to cancer cells to suppress the glycolysis-associated SLC2A1 and HK1 expression, thus significantly inhibiting the migration and invasion of a murine breast cancer cell line in vitro and the corresponding subcutaneous tumor mouse model in vivo. Such unsymmetrical low-generation phosphorus dendrimers may be extended to deliver other genetic materials to tackle other diseases.

Bioactive Phosphorus Dendrimers as a Universal Protein Delivery System for Enhanced Anti-inflammation Therapy.

Nanocarrier-based cytoplasmic protein delivery offers opportunities to develop protein therapeutics; however, many delivery systems are positively charged, causing severe toxic effects. For enhanced therapeutics, it is also of great importance to design nanocarriers with intrinsic bioactivity that can be integrated with protein drugs due to the limited bioactivity of proteins alone for disease treatment. We report here a protein delivery system based on anionic phosphite-terminated phosphorus dendrimers with intrinsic anti-inflammatory activity. A phosphorus dendrimer termed AK-137 with optimized anti-inflammatory activity was selected to complex proteins through various physical interactions. Model proteins such as bovine serum albumin, ribonuclease A, ovalbumin, and fibronectin (FN) can be transfected into cells to exert their respective functions, including cancer cell apoptosis, dendritic cell maturation, or macrophage immunomodulation. Particularly, the constructed AK-137@FN nanocomplexes display powerful therapeutic effects in acute lung injury and acute gout arthritis models by integrating the anti-inflammatory activity of both the carrier and protein. The developed anionic phosphite-terminated phosphorus dendrimers may be employed as a universal carrier for protein delivery and particularly utilized to deliver proteins and fight different inflammatory diseases with enhanced therapeutic efficacy.

Low-Generation Cationic Phosphorus Dendrimers: Novel Approach to Tackle Drug-Resistant S. aureus In Vitro and In Vivo.

The incessant, global increase in antimicrobial resistance (AMR) is a very big challenge for healthcare systems. AMR is predicted to grow at an alarming pace, with a dramatic increase in morbidity, mortality, and a 100 trillion US$ loss to the global economy by 2050. The mortality rate caused by methicillin-resistant S. aureus (MRSA) is much higher as compared to infections caused by drug-susceptible S. aureus. Additionally, there is a big paucity of therapeutics available for treatment of serious infections caused by MRSA. Thus, the discovery and development of novel therapies is an urgent, unmet medical need. In this context, we synthesized AE4G0, a low-generation cationic-phosphorus dendrimer expressing potent antimicrobial activity against S. aureus and Enterococcus sp., and demonstrating a broad selectivity index against eukaryotic cells. AE4G0 exhibits concentration-dependent, bactericidal activity and synergizes with gentamicin, especially against gentamicin-resistant MRSA NRS119. Fluorescence and scanning electron microscopy demonstrate that treatment with AE4G0 led to the utter destruction of S. aureus ATCC 29213 without inducing resistance, despite repeated exposure. When tested in vivo, AE4G0 demonstrates significant efficacy against S. aureus ATCC 29213, alone and in combination with gentamicin against gentamicin-resistant S. aureus NRS119 in the murine skin model of infection. Taken together, AE4G0 demonstrates the potential to be translated as a novel therapeutic option for the treatment of topical, drug-resistant S. aureus infections.

Liquid-Crystalline Order in the Phosphorus-Containing DenDrimers.

The structure of phosphorus-containing dendrimers has been studied by IR spectroscopy and optical polarization microscopy. The repeating units of dendrimer molecules are mesogens. This property arises from the conjugation of the aromatic ring and the hydrazone group. An analysis of the IR spectra showed that, with an increase in the generation number, the width of the stretching vibration bands ν(PN) and ν(PO) increases. Difficulties in packing molecules of higher generations cause conformational diversity. The shape of the dendrimer molecules was determined by analyzing the increments of dipole moments. Additionally, the modeling of the stacking of repeating links was performed. The spherical model of molecules does not satisfy the experimental dipole moments of the dendrimers. The flat disk model is more suitable for explaining step changes in dipole moments. The liquid-crystalline ordering of dendrimers under the action of applied pressure was found. With simultaneous heating and uniaxial compression, optical anisotropy appears in dendrimers. It is associated with the formation of liquid-crystalline order. However, a thermodynamically stable liquid-crystalline phase is not formed in this case. Dendrimers most likely have disk-shaped molecules.

Modulation of Macrophages Using Nanoformulations with Curcumin to Treat Inflammatory Diseases: A Concise Review.

Curcumin (Cur), a traditional Chinese medicine extracted from natural plant rhizomes, has become a candidate drug for the treatment of diseases due to its anti-inflammatory, anticancer, antioxidant, and antibacterial activities. However, the poor water solubility and low bioavailability of Cur limit its therapeutic effects for clinical applications. A variety of nanocarriers have been successfully developed to improve the water solubility, in vivo distribution, and pharmacokinetics of Cur, as well as to enhance the ability of Cur to polarize macrophages and relieve macrophage oxidative stress or anti-apoptosis, thus accelerating the therapeutic effects of Cur on inflammatory diseases. Herein, we review the design and development of diverse Cur nanoformulations in recent years and introduce the biomedical applications and potential therapeutic mechanisms of Cur nanoformulations in common inflammatory diseases, such as arthritis, neurodegenerative diseases, respiratory diseases, and ulcerative colitis, by regulating macrophage behaviors. Finally, the perspectives of the design and preparation of future nanocarriers aimed at efficiently exerting the biological activity of Cur are briefly discussed.

Engineered Stable Bioactive Per Se Amphiphilic Phosphorus Dendron Nanomicelles as a Highly Efficient Drug Delivery System To Take Down Breast Cancer In Vivo.

Conventional small molecular chemical drugs always have challenging limitations in cancer therapy due to their high systemic toxicity and low therapeutic efficacy. Nanotechnology has been applied in drug delivery, bringing new promising potential to realize effective cancer treatment. In this context, we develop here a new nanomicellar drug delivery platform generated by amphiphilic phosphorus dendrons (1-C17G3.HCl), which could form micelles for effective encapsulation of a hydrophobic anticancer drug doxorubicin (DOX) with a high drug loading content (42.4%) and encapsulation efficiency (96.7%). Owing to the unique dendritic rigid structure and surface hydrophilic groups, large steady void space of micelles can be created for drug encapsulation. The created DOX-loaded micelles with a mean diameter of 26.3 nm have good colloidal stability. Strikingly, we show that the drug-free micelles possess good intrinsic anticancer activity and act collectively with DOX to take down breast cancer cells in vitro and the xenografted tumor model in vivo through upregulation of Bax, PTEN, and p53 proteins for enhanced cell apoptosis. Meanwhile, the resulting 1-C17G3.HCl@DOX micelles significantly abolish the toxicity relevant to the free drug. The findings of this study demonstrate a unique nanomicelle-based drug delivery system created with the self-assembling amphiphilic phosphorus dendrons that may be adapted for chemotherapy of different cancer types.

Phosphorus dendron nanomicelles as a platform for combination anti-inflammatory and antioxidative therapy of acute lung injury.

Rationale: Development of novel nanomedicines to inhibit pro-inflammatory cytokine expression and reactive oxygen species (ROS) generation for anti-inflammatory therapy of acute lung injury (ALI) remains challenging. Here, we present a new nanomedicine platform based on tyramine-bearing two dimethylphosphonate sodium salt (TBP)-modified amphiphilic phosphorus dendron (C11G3) nanomicelles encapsulated with antioxidant drug curcumin (Cur). Methods: C11G3-TBP dendrons were synthesized via divergent synthesis and self-assembled to generate nanomicelles in a water environment to load hydrophobic drug Cur. The created C11G3-TBP@Cur nanomicelles were well characterized and systematically examined in their cytotoxicity, cellular uptake, intracellular ROS elimination, pro-inflammatory cytokine inhibition and alveolar macrophages M2 type repolarization in vitro, and evaluated to assay their anti-inflammatory and antioxidative therapy effects of ALI mice model through pro-inflammatory cytokine expression level in bronchoalveolar lavage fluid and lung tissue, histological analysis and micro-CT imaging detection of lung tissue injury in vivo. Results: The nanomicelles with rigid phosphorous dendron structure enable high-capacity and stable Cur loading. Very strikingly, the drug-free C11G3-TBP micelles exhibit excellent cytocompatibility and intrinsic anti-inflammatory activity through inhibition of nuclear transcription factor-kappa B, thus causing repolarization of alveolar macrophages from M1 type to anti-inflammatory M2 type. Taken together with the strong ROS scavenging property of the encapsulated Cur, the developed nanomicelles enable effective therapy of inflammatory alveolar macrophages in vitro and an ALI mouse model in vivo after atomization administration. Conclusion: The created phosphorus dendron nanomicelles can be developed as a general nanomedicine platform for combination anti-inflammatory and antioxidative therapy of inflammatory diseases.

Crown Macromolecular Derivatives: Stepwise Design of New Types of Polyfunctionalized Phosphorus Dendrimers.

Phosphorus dendrimers are used for many applications in different domains including nanomedicine as cargo of drugs or as species active per se but also in a variety of other fields ranging from nanoscience to catalysis. Their properties depend on the nature of their internal structure and mainly of the diversity and versatility of the functional groups located on their outer shell. Therefore, there is a need to diversify their structure in order to use them for new applications and to propose alternative synthetic pathways to be built easily, at each step and in high yield a family of original stable phosphorus dendrimers of different generations. Such a goal is illustrated in this report with the original synthesis of 14 new phosphorus dendrimers of generation 0 to 2 and the possibility to modify at will their internal structure and the nature of their functional end groups.

First-in-Class Phosphorus Dendritic Framework, a Wide Surface Functional Group Palette Bringing Noteworthy Anti-Cancer and Anti-Tuberculosis Activities: What Lessons to Learn?

Based on phenotypic screening, the major advantages of phosphorus dendrimers and dendrons as drugs allowed the discovery of new therapeutic applications, for instance, as anti-cancer and anti-tuberculosis agents. These biological activities depend on the nature of the chemical groups (neutral or cationic) on their surface as well as their generation. As lessons to learn, in the oncology domain, the increase in the generation of metallo-dendrimers is in the same direction as the anti-proliferative activities, in contrast to the development of polycationic dendrimers, where the most potent anti-tuberculosis phosphorus dendrimer was observed to have the lowest generation (G0). The examples presented in this original analysis of phosphorus dendrimers and dendrons provide support for the lessons learned and for the development of new nanoparticles in nanomedicine.

Safe Polycationic Dendrimers as Potent Oral In Vivo Inhibitors of Mycobacterium tuberculosis: A New Therapy to Take Down Tuberculosis.

The long-term treatment of tuberculosis (TB) sometimes leads to nonadherence to treatment, resulting in multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis. Inadequate bioavailability of the drug is the main factor for therapeutic failure, which leads to the development of drug-resistant cases. Therefore, there is an urgent need to design and develop novel antimycobacterial agents minimizing the period of treatment and reducing the propagation of resistance at the same time. Here, we report the development of original and noncytotoxic polycationic phosphorus dendrimers essentially of generations 0 and 1, but also of generations 2-4, with pyrrolidinium, piperidinium, and related cyclic amino groups on the surface, as new antitubercular agents active per se, meaning with intrinsic activity. The strategy is based on the phenotypic screening of a newly designed phosphorus dendrimer library (generations 0-4) against three bacterial strains: attenuated Mycobacterium tuberculosis H37Ra, virulent M. tuberculosis H37Rv, and Mangora bovis BCG. The most potent polycationic phosphorus dendrimers 1G0,HCl and 2G0,HCl are active against all three strains with minimum inhibitory concentrations (MICs) between 3.12 and 25.0 µg/mL. Both are irregularly shaped nanoparticles with highly mobile branches presenting a radius of gyration of 7 Å, a diameter of maximal 25 Å, and a solvent-accessible surface area of dominantly positive potential energy with very localized negative patches arising from the central N3P3 core, which steadily interacts with water molecules. The most interesting is 2G0,HCl, showing relevant efficacy against single-drug-resistant (SDR) M. tuberculosis H37Rv, resistant to rifampicin, isoniaid, ethambutol, or streptomycin. Importantly, 2G0,HCl displayed significant in vivo efficacy based on bacterial counts in lungs of infected Balb/C mice at a dose of 50 mg/kg oral administration once a day for 2 weeks and superior efficacy in comparison to ethambutol and rifampicin. This series of polycationic phosphorus dendrimers represents first-in-class drugs to treat TB infection, could fulfill the clinical candidate pipe of this high burden of infectious disease, and play a part in addressing the continuous demand for new drugs.

Facile Synthesis of Amphiphilic Fluorescent Phosphorus Dendron-Based Micelles as Antiproliferative Agents: First Investigations.

We designed and synthesized several families of novel amphiphilic fluorescent phosphorus dendron-based micelles showing relevant antiproliferative activities for use in the field of theranostic nanomedicine. Based on straightforward synthesis pathways, 12 amphiphilic phosphorus dendrons bearing 10 protonated cyclic amino groups (generation one), or 20 protonated amino groups (generation two), and 1 hydrophobic chain carrying 1 fluorophore moiety were created. The amphiphilic dendron micelles had the capacity to aggregate in solution using hydrophilic/hydrophobic interactions, which promoted the formation of polymeric micelles. These dendron-based micelles showed moderate to high antiproliferative activities against a panel of tumor cell lines. This paper presents for the first time the synthesis and our first investigations of new phosphorus dendron-based micelles for cancer therapy applications.

Multivalent Copper(II)-Conjugated Phosphorus Dendrimers with Noteworthy In Vitro and In Vivo Antitumor Activities: A Concise Overview.

Dendrimers are macromolecules with well-defined, homogeneous, and monodispersed structures that form a branch-like structure. In general, they have a symmetric core, inner shells, and an outer shell. Over the past decade, metallodendritic architectures have developed into a new area in nanomedicine. Due to their versatility and facile customization, phosphorus dendrimers represent interesting platforms for biomedical applications. Metallo-conjugated phosphorus dendrimers have been developed within the dendrimer space, an important part of the chemical space. The first investigation was made using phosphorus dendrimers bearing copper(II) groups on their surface as the original anticancer drug candidates. The aim of this minireview is to present our powerful strategy to find and develop original multivalent copper(II)-conjugated phosphorus dendrimers. The most potent of them is G3 dendrimers with N-(pyridine-2-ylmethylene)ethanamine as the chelating motif complexed with Cu(II) (1G3-Cu), showing very good in vitro and in vivo antiproliferative efficacy. On the basis of these results, 1G3-Cu is a potential clinical candidate having progressed from hit to preclinical candidate status.

From Riluzole to Dexpramipexole via Substituted-Benzothiazole Derivatives for Amyotrophic Lateral Sclerosis Disease Treatment: Case Studies.

The 1,3-benzothiazole (BTZ) ring may offer a valid option for scaffold-hopping from indole derivatives. Several BTZs have clinically relevant roles, mainly as CNS medicines and diagnostic agents, with riluzole being one of the most famous examples. Riluzole is currently the only approved drug to treat amyotrophic lateral sclerosis (ALS) but its efficacy is marginal. Several clinical studies have demonstrated only limited improvements in survival, without benefits to motor function in patients with ALS. Despite significant clinical trial efforts to understand the genetic, epigenetic, and molecular pathways linked to ALS pathophysiology, therapeutic translation has remained disappointingly slow, probably due to the complexity and the heterogeneity of this disease. Many other drugs to tackle ALS have been tested for 20 years without any success. Dexpramipexole is a BTZ structural analog of riluzole and was a great hope for the treatment of ALS. In this review, as an interesting case study in the development of a new medicine to treat ALS, we present the strategy of the development of dexpramipexole, which was one of the most promising drugs against ALS.

In Search of a Phosphorus Dendrimer-Based Carrier of Rose Bengal: Tyramine Linker Limits Fluorescent and Phototoxic Properties of a Photosensitizer.

Photodynamic therapy (PDT) is a skin cancer treatment alternative to chemotherapy and radiotherapy. This method exploits three elements: a phototoxic compound (photosensitizer), light source and oxygen. Upon irradiation by light of a specific wavelength, the photosensitizer generates reactive oxygen species triggering the cascade of reactions leading to cell death. The positive therapeutic effect of PDT may be limited due to low solubility, low tumor specificity and inefficient cellular uptake of photosensitizers. A promising approach to overcome these obstacles involves the use of nanocarrier systems. The aim of this initial study was to determine the potential of the application of phosphorus dendrimers as carriers of a photosensitizer-rose bengal (RB). The primary goal involved the synthesis and in vitro studies of covalent drug-dendrimer conjugates. Our approach allowed us to obtain RB-dendrimer conjugates with the use of tyramine as an aromatic linker between the carrier and the drug. The compounds were characterized by FT-IR, 1H NMR, 13C NMR, 31P NMR, size and zeta potential measurements and spectrofluorimetric analysis. The dialysis to check the drug release from the conjugate, flow cytometry to specify intracellular uptake, and singlet oxygen generation assay were also applied. Finally, we used MTT assay to determine the biological activity of the tested compounds. The results of our experiments indicate that the conjugation of RB to phosphorus dendrimers via the tyramine linker decreases photodynamic activity of RB.

Revisiting Cationic Phosphorus Dendrimers as a Nonviral Vector for Optimized Gene Delivery Toward Cancer Therapy Applications.

Gene delivery, one important cancer-therapy mode, still remains to be challenging because of the shortage of highly efficient and safe nonviral vectors. Here, we revisit the development of cationic phosphorus dendrimers by synthesizing them with different generations (G1-3) and surface ligands (1-(2-aminoethyl) pyrrolidine, 1-(3-aminopropyl) piperidine, or 1-(2-aminoethyl) piperidine) for optimized gene delivery toward cancer-gene-therapy applications. First, the synthesized dendrimer derivatives were employed to condense plasmid DNA (pDNA) encoding enhanced green fluorescent protein (EGFP) to optimize their gene-delivery efficiency by varying the dendrimer generations and surface polycationic ligands. We show that all dendrimer/pDNA polyplexes display good cytocompatibility, and the 1-(2-aminoethyl) pyrrolidine-modified protonated G1 dendrimers (1-G1) display the best gene-delivery efficiency to HeLa cells under the same conditions through flow cytometry and fluorescence microscopic imaging analyses. Hence, 1-G1 dendrimers were then used as a vector to transfect pDNA encoding both EGFP and p53 protein for cancer-gene-therapy applications. Our results reveal that under the optimized conditions, the transfection of pDNA induces the significant p53 protein expression as verified through the resulted cell cycle arrest (regulation of p21 and Cdk4/Cyclin-D1 expression) and Western blotting. The cancer-gene-therapy potential of the polyplexes was finally validated through therapy of a xenografted tumor model after intratumoral injection without systemic toxicity. The developed cationic 1-G1 dendrimers may be adopted as a powerful vector system for gene therapy of cancer, as well as for highly effective gene therapy of other diseases.

Potent Anticancer Efficacy of First-In-Class CuII and AuIII Metaled Phosphorus Dendrons with Distinct Cell Death Pathways.

First-in-class CuII and AuIII metaled phosphorus dendrons were synthesized and showed significant antiproliferative activity against several aggressive breast cancer cell lines. The data suggest that the cytotoxicity increases with reducing length of the alkyl chains, whereas the replacement of CuII with AuIII considerably increases the antiproliferative activity of metaled phosphorus dendrons. Very interestingly, we found that the cell death pathway is related to the nature of the metal complexed by the plain dendrons. CuII metaled dendrons showed a potent caspase-independent cell death pathway, whereas AuIII metaled dendrons displayed a caspase-dependent apoptotic pathway. The complexation of plain dendrons with AuIII increased the cellular lethality versus dendrons with CuII and promoted the translocation of Bax into the mitochondria and the release of Cytochrome C (Cyto C).

Metal-based phosphorus dendrimers as novel nanotherapeutic strategies to tackle cancers: A concise overview.

Several metal-based phosphorus dendrimers were prepared. The first series developed by us was the Cu(II) series. In this series, the most potent is the third generation-Cu(II) showing original mechanism of action with activation of the pro-apoptotic Bax protein. To our knowledge, it is the first example of nanoparticles displaying Bax protein activation and then cell death through apoptosis process. Interestingly, this dendritic-Cu(II) complex showed synergistic effect with doxorubicin. Based on these interesting anti-proliferative activities, we developed Au(III)-conjugated phosphorus dendrimers. The most potent is the third generation-Au(III) dendrimer which represents also a new and promising first-in-class anti-proliferative agent against both solid and liquid tumor cell lines. Then, in order to analyze the influence of the metal moiety distribution of Cu(II) and Au(III) on the surface of dendrimers, mix Cu(II)-Au(III)-conjugated phosphorus dendrimers were also prepared and tested as anti-proliferative agents. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.