Site-Specific Labeling of Cyanine and Porphyrin Dye-Stabilized Nanoemulsions with Affibodies for Cellular Targeting

Repurposing indocyanine green: exploring the potential of an old drug in modern medicine

The repurposing of existing drugs, referred to as theranostics, has made profound impacts on precision medicine. Indocyanine green (ICG), a well-established and clinical dye, has continued to be a star agent, described as a multifunctional molecule with concurrent photo- or sono-sensitiveness capabilities and co-delivery accessibility, showing remarkable potential in the area of unimodal or multimodal imaging-guided therapy of various diseases, leading to the extensive consideration of immediate clinical translations. In this review, we strive to bring the understanding of repurposing performance assessment for ICG into practice by clarifying the relationships between its features and applicability. Specifically, we address the obstacles encountered in the process of developing an ICG repurposing strategy, as well as the noteworthy advancements made in the field of ICG repurposing. We also go into detail about the structure-function correlations of drugs containing ICG and how different structural groups significantly affect the physicochemical properties.

Dual-targeting nanotheranostics for MRI-guided enhanced chemodynamic therapy of hepatoma via regulating the tumor microenvironment

Chemodynamic therapy (CDT), as a reactive oxygen species (ROS)-based therapeutic modality, has attracted much attention in recent years. However, the insufficient therapeutic effect of CDT is due to the antioxidant system in the tumor microenvironment, such as high levels of glutathione (GSH). In this study, we developed a biological/physical dual-targeting nanotheranostic agent (relaxation rate, r1: 6.3 mM-1 s-1 and r2: 13.11 mM-1 s-1) for enhanced CDT of SMCC-7721 tumors. This nanotheranostic agent is composed of a homologous tumor cell membrane (TCM), magnetic ferric oxide, and manganese oxide and is denoted as FM@TCM nanoparticles (NPs). A favorable effect of in vitro CDT on SMCC-7721 cells (IC50: 20 μg mL-1) is demonstrated, attributed to the Fenton reaction and oxidative stress resulting from the reduction of the GSH level. In vivo T1/T2 magnetic resonance imaging (MRI) confirms that the tumor accumulation of FM@TCM NPs is promoted by concurrent bioactive targeting of the homologous TCM and physico-magnetic targeting of tumor tissues with an external magnetic field. Impressive chemodynamic therapeutic effects on SMCC-7721 tumors are demonstrated through the catalysis of endogenous hydrogen peroxide and depletion of GSH to generate high levels of ROS. Dual-targeting FM@TCM NPs inhibit SMCC-7721 tumor growth (∼90.9%) in vivo without any biotoxicity. This nanotheranostic agent has great potential for use in MRI-guided CDT.

Profiling the Heme-Binding Proteomes of Bacteria Using Chemical Proteomics

Heme is a cofactor with myriad roles and essential to almost all living organisms. Beyond classical gas transport and catalytic functions, heme is increasingly appreciated as a tightly controlled signalling molecule regulating protein expression. However, heme acquisition, biosynthesis and regulation is poorly understood beyond a few model organisms, and the heme-binding proteome has not been fully characterised in bacteria. Yet as heme homeostasis is critical for bacterial survival, heme-binding proteins are promising drug targets. Herein we report a chemical proteomics method for global profiling of heme-binding proteins in live cells for the first time. Employing a panel of heme-based clickable and photoaffinity probes enabled the profiling of 32-54 % of the known heme-binding proteomes in Gram-positive and Gram-negative bacteria. This simple-to-implement profiling strategy could be interchangeably applied to different cell types and systems and fuel future research into heme biology.

Artificial Scaffold Polypeptides As an Efficient Tool for the Targeted Delivery of Nanostructures In Vitro and In Vivo

The use of traditional tools for the targeted delivery of nanostructures, such as antibodies, transferrin, lectins, or aptamers, often leads to an entire range of undesirable effects. The large size of antibodies often does not allow one to reach the required number of molecules on the surface of nanostructures during modification, and the constant domains of heavy chains, due to their effector functions, can induce phagocytosis. In the recent two decades, targeted polypeptide scaffold molecules of a non-immunoglobulin nature, antibody mimetics, have emerged as much more effective targeting tools. They are small in size (3-20 kDa), possess high affinity (from subnano- to femtomolar binding constants), low immunogenicity, and exceptional thermodynamic stability. These molecules can be effectively produced in bacterial cells, and, using genetic engineering manipulations, it is possible to create multispecific fusion proteins for the targeting of nanoparticles to cells with a given molecular portrait, which makes scaffold polypeptides an optimal tool for theranostics.

Comparative Evaluation of Engineered Polypeptide Scaffolds in HER2-Targeting Magnetic Nanocarrier Delivery

Targeted drug delivery is one of the most intriguing and challenging issues in modern biomedicine. For active targeting, full-size IgG molecules (150 kDa) are usually used. Recent studies have revealed that small artificial polypeptide scaffolds such as DARPins (14 kDa) and affibodies (8 kDa) are much more promising tools for drug delivery due to their small size, artificial nature, low immunogenicity, and many other properties. However, there is no comparative information on the targeting abilities of scaffold polypeptides, which should be taken into account when developing drug delivery systems (DDSs). The present work is the first comprehensive study on the comparison of the effectiveness of different HER2-targeting proteins within the architecture of nanoparticles. Namely, we synthesized trimodal nanoparticles: magnetic, fluorescent, and directed toward HER2 oncomarker on cancer cells. The magnetic particles (MPs) were covalently modified with (i) full-size IgG, 150 kDa, (ii) DARPin_G3, 14 kDa, and (iii) affibody Z_HER2:342, 8 kDa. We showed that the number of DARPin_G3 and affibody Z_HER2:342 molecules conjugated to the nanoparticle surface are 10 and 40 times higher, respectively, than the corresponding value for trastuzumab. Using the methods of magnetic particle quantification (MPQ)-cytometry and confocal microscopy, we showed that all types of the obtained magnetic conjugates specifically labeled HER2-overexpressing cells. Namely, we demonstrated that particle binding to HER2-positive cells is 1113 ± 39 fg/cell for MP*trastuzumab, 1431 ± 186 fg/cell for MP*Z_HER2:342, and 625±21 fg/cell for MP*DARPin_G3, which are 2.77, 2.75, and 2.30 times higher than the corresponding values for control HER2-negative cells. Thus, we showed that the smallest HER2-recognizing polypeptide affibody Z_HER2:342 is more effective in terms of specificity and selectivity in nanoparticle-mediated cell labeling.

Combined fluorescence-guided surgery and photodynamic therapy for glioblastoma multiforme using cyanine and chlorin nanocluster

INTRODUCTION

Glioblastoma multiforme (GBM) is the most common primary intracranial malignancy; survival can be improved by maximizing the extent-of-resection.

METHODS

A near-infrared fluorophore (Indocyanine-Green, ICG) was combined with a photosensitizer (Chlorin-e6, Ce6) on the surface of superparamagnetic-iron-oxide-nanoparticles (SPIONs), all FDA-approved for clinical use, yielding a nanocluster (ICS) using a microemulsion. The physical-chemical properties of the ICS were systematically evaluated. Efficacy of photodynamic therapy (PDT) was evaluated in vitro with GL261 cells and in vivo in a subtotal resection trial using a syngeneic flank tumor model. NIR imaging properties of ICS were evaluated in both a flank and an intracranial GBM model.

RESULTS

ICS demonstrated high ICG and Ce6 encapsulation efficiency, high payload capacity, and chemical stability in physiologic conditions. In vitro cell studies demonstrated significant PDT-induced cytotoxicity using ICS. Preclinical animal studies demonstrated that the nanoclusters can be detected through NIR imaging in both flank and intracranial GBM tumors (ex: 745 nm, em: 800 nm; mean signal-to-background 8.5 ± 0.6). In the flank residual tumor PDT trial, subjects treated with PDT demonstrated significantly enhanced local control of recurrent neoplasm starting on postoperative day 8 (23.1 mm3 vs 150.5 mm3, p = 0.045), and the treatment effect amplified to final mean volumes of 220.4 mm3 vs 806.1 mm3 on day 23 (p = 0.0055).

CONCLUSION

A multimodal theragnostic agent comprised solely of FDA-approved components was developed to couple optical imaging and PDT. The findings demonstrated evidence for the potential theragnostic benefit of ICS in surgical oncology that is conducive to clinical integration.

Azides and Porphyrinoids: Synthetic Approaches and Applications. Part 1-Azides, Porphyrins and Corroles

Azides and porphyrinoids (such as porphyrin and corrole macrocycles) can give rise to new derivatives with significant biological properties and as new materials' components. Significant synthetic approaches have been studied. A wide range of products (e.g., microporous organic networks, rotaxane and dendritic motifs, dendrimers as liquid crystals, as blood substitutes for transfusions and many others) can now be available and used for several medicinal and industrial purposes.

Click Chemistry-Based Two-Component System for Efficient Inhibition of Human Immunodeficiency Virus (HIV) Reverse Transcriptase (RT)

We synthesized two dTTP analogues for copper-free "click" chemistry-coupling in the active sites of DNA polymerases. We found that in the presence of both analogues, human immunodeficiency virus (HIV) reverse transcriptase (RT) activity was suppressed by up to 93%. This inhibitory effect was not recovered by an excess amount of primer-template unlike that for a conventional HIV RT inhibitor, azidothymidine. This finding may become the basis for the development of efficient in vivo inhibitors of HIV RT and other DNA polymerases.

Cyanine-Assisted Exfoliation of Covalent Organic Frameworks in Nanocomposites for Highly Efficient Chemo-Photothermal Tumor Therapy

Covalent organic frameworks (COFs) have received considerable interest because of their advanced applications. However, their low dispersibility and aqueous stability are intractable issues limiting their biomedical application. To address the issue, water-dispersible nanocomposites (COF@IR783) produced through the assembly of cyanines and COFs are proposed and prepared. Therefore, a strategy of "killing three birds with one stone" is developed. First, the nanocomposites exhibit superior dispersibility and aqueous stability compared to COFs. The nanocomposites have a nanosized morphology and negative charges, which are in favor of improving the blood circulation and enhanced permeability and retention-mediated tumor-targeting delivery therapy for in vivo application. Second, the nanocomposites have enhanced photothermal therapy (PTT) ability in the near-infrared region compared to cyanines. The nanocomposites also have a photoacoustic imaging ability, which can guide the antitumor therapy in vivo. Lastly, the nanocomposites can be further used as drug-delivery carriers for loading the anticancer cis-aconityl-doxorubicin (CAD) prodrug. In comparison with individual PTT or chemotherapy, the combination of PTT and chemotherapy achieved with COF@IR783@CAD synergistically induced the death of cancer cells in vitro, and an intravenous injection of COF@IR783@CAD in mice resulted in significant tumor ablation. This work indicates that the dispersibility and aqueous stability of COFs can be appropriately overcome through a rational design and can further expand the biomedical applications of COFs.

Chlorin e6-Coated Superparamagnetic Iron Oxide Nanoparticle (SPION) Nanoclusters as a Theranostic Agent for Dual-Mode Imaging and Photodynamic Therapy

Photodynamic therapy (PDT) is an approved modality for the treatment of various types of maligancies and diseased states. However, most of the available photosensitizers (PS) are highly hydrophobic, which limits their solubility and dispersion in biological fluids and can lead to self-quenching and sub-optimal therapeutic efficacy. In this study, chlorin e6 (Ce6)-coated superparamagnetic iron oxide nanoparticle (SPION) nanoclusters (Ce6-SCs) were prepared via an oil-in-water emulsion. The physical-chemical properties of the Ce6-SCs were systematically evaluated. Dual-mode imaging and PDT was subsequently performed in tumor-bearing mice. Chlorin e6 is capable of solubilizing hydrophobic SPION into stable, water-soluble nanoclusters without the use of any additional amphiphiles or carriers. The method is reproducible and the Ce6-SCs are highly stable under physiological conditions. The Ce6-SCs have an average diameter of 92 nm and low polydispersity (average PDI < 0.2). Encapsulation efficiency of both Ce6 and SPION is ≈100%, and the total Ce6 payload can be as high as 56% of the total weight (Ce6 + Fe). The Ce6-SCs localize within tumors via enhanced permeability and retention and are detectable by magnetic resonance (MR) and optical imaging. With PDT, Ce6-SCs demonstrate high singlet oxygen generation and produce a significant delay in tumor growth in mice.