Bioconjugate Chemistry最新文献

Positron-emission tomography (PET) offers high sensitivity for cancer diagnosis. However, small-molecule-based probes often exhibit insufficient accumulation in tumor sites, while nanoparticle-based agents typically have limited delivery efficiency. To address this challenge, this study proposes a novel PET imaging probe, ⁶⁸Ga-CBT-PSMA, designed for prostate cancer. This probe integrates an intracellular self-assembly strategy to enhance PET imaging signals and significantly improve the signal-to-noise ratio. The glutamate-urea-based prostate-specific membrane antigen (PSMA)-targeting motif enables specific recognition of prostate cancer cells and enhances cellular uptake; then the self-assembly process induced by glutathione reduction effectively accumulates the probe within tumor cells, thereby amplifying PET imaging signals. This approach not only enhances signal intensity and resolution but also facilitates precise cancer localization and diagnosis, offering new avenues for advancing cancer diagnostic techniques.

OncoFAP is an ultrahigh affinity ligand of fibroblast activation protein (FAP), a tumor-associated antigen overexpressed in the stroma of the majority of solid tumors. OncoFAP has been previously implemented as a tumor-homing moiety for the development of small molecule drug conjugates (SMDCs). In the same context, the glycine--proline dipeptide was included with the aim to selectively undergo cleavage only in the presence of the target FAP, triggering the consequent release of the cytotoxic payload in the tumor microenvironment. In this work, we evaluate the use of monomethyl auristatin F (MMAF) as a payload, a close derivative of MMAE bearing a charged carboxylic acid that hampers its cellular permeability, typically employed in the development of internalizing antibody-drug conjugates. The novel OncoFAP-GlyPro-MMAF and the previously described OncoFAP-GlyPro-MMAE were compared in a head-to-head therapeutic experiment in mice bearing FAP-positive tumors. Surprisingly, the MMAF conjugate mediated potent antitumor activity, despite its poor cellular permeability.

The present study reports the preparation of the first multivalent iminosugars built onto a glyco-gold nanoparticle core (glyco-AuNPs) capable of stabilizing or enhancing the activity of the lysosomal enzyme GCase, which is defective in Gaucher disease. An N-nonyltrihydroxypiperidine was selected as the bioactive iminosugar unit and further functionalized, via copper-catalyzed alkyne-azide cycloaddition, with a thiol-ending linker that allowed the conjugation to the gold core. These bioactive ligands were obtained with either a linear monomeric or dendritic trimeric arrangement of the iminosugar. The concentration of the bioactive iminosugar on the gold surface was modulated with different amounts of a glucoside bearing a short thiol-ending spacer as the inner ligand. The new mixed-ligand coated glyco-AuNPs were fully characterized, and those with the highest colloidal stability in aqueous medium were subjected to biological evaluation. Glyco-AuNPs with trimeric iminosugar bioactive units showed the ability to stabilize recombinant GCase in a thermal denaturation assay, while Glyco-AuNPs with monomeric iminosugar bioactive units were able to enhance the activity of mutant GCase in Gaucher patient's fibroblasts by 1.9-fold at 2.2 μM.

Self-propelled micro/nanomotors (MNMs) represent a groundbreaking advancement in precision drug delivery, offering potential solutions to persistent challenges such as systemic toxicity, limited bioavailability, and nonspecific distribution. By transforming various energy sources into mechanical motion, MNMs are able to autonomously navigate through complex physiological environments, facilitating targeted delivery of therapeutic agents to previously inaccessible regions. However, to achieve efficient in vivo drug delivery, biomedical MNMs must demonstrate their ability to overcome crucial physiological barriers encompassing mucosal surfaces, blood flow dynamics, vascular endothelium, and cellular membrane. This review provides a comprehensive overview of the latest strategies developed to address these obstacles while also analyzing the broader challenges and opportunities associated with clinical translation. Our objective is to establish a solid foundation for future research in medical MNMs by focusing on enhancing drug delivery efficiency and advancing precision medicine, ultimately paving the way for practical theragnostic applications and wider clinical adoption.

To enhance the affinity of peptide ligands for their targets, covalent warheads can be engineered to facilitate irreversible binding. This study aimed at exploring the potential of a ⁶⁸Ga-labeled peptidomimetic radioligand, [⁶⁸Ga]Ga-DOTA-RQAR-kbt, for PET imaging through its irreversible binding to the suppression of tumorigenicity 14 (ST14). An Arg-Gln-Ala-Arg (RQAR) tetrapeptide was conjugated with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid for gallium-68 radiolabeling. The covalent warhead ketobenzothiazole was constructed as a serine trap for ST14 protease, resulting in the formation of DOTA-RQAR-kbt. We compared both the in vitro and in vivo properties of [⁶⁸Ga]Ga-DOTA-RQAR-kbt with those of its reversible-binding counterparts, [⁶⁸Ga]Ga-DOTA-RQAR-OH. DOTA-RQAR-kbt exhibits high affinity for ST14 and irreversibly binds to ST14, as evidenced by the lack of ST14 activity recovery following ultrafiltration. In contrast, DOTA-RQAR-OH shows reversible binding and has low affinity for ST14. PET/CT imaging confirmed the superior tumor targeting of [⁶⁸Ga]Ga-DOTA-RQAR-kbt compared to the [⁶⁸Ga]Ga-DOTA-RQAR-OH, with robust signals observed at 0.5, 1, and 2 h postinjection. Blocking studies underscored the probe's specificity, as they revealed a marked reduction in tumor uptake in the presence of excess RQAR-kbt. Biodistribution studies demonstrated significantly higher tumor uptake for [⁶⁸Ga]Ga-DOTA-RQAR-kbt, with 0.89 ± 0.03%ID/g at 1 h postinjection, which was reduced to 0.25 ± 0.03%ID/g (P < 0.01) in the presence of excess RQAR-kbt. In this proof-of-concept study, an irreversibly binding peptidomimetic radioligand targeting ST14 was evaluated, demonstrating improved tumor uptake in vivo compared with its reversibly binding counterparts. This approach holds promise for improving the potency of covalent radiotracers as PET agents.

mRNA lipid nanoparticles (LNPs) are a powerful technology that are actively being investigated for their ability to prevent, treat, and study disease. However, a major limitation remains: achieving extrahepatic mRNA expression. The development of new carriers could enable the expression of mRNA in non-liver targets, thus expanding the utility of mRNA-based medicines. In this study, we use a combination of chemoinformatic-guided material synthesis and design of experiment optimization for the development of a spleen-expressing lipid nanoparticle (SE-LNP). We begin with the synthesis of a novel cholesterol derivative followed by SE-LNP formulation and design of experiment-guided optimization to identify three lead SE-LNPs. We then evaluate their in vitro delivery mechanism, in vivo biodistribution, and protein expression in mice, ultimately achieving spleen-preferential expression. The goal of this paper is thus to create LNPs that preferentially express mRNA in the spleen upon intravenous delivery, demonstrating the potential of LNPs to modulate gene expression in extrahepatic tissues for disease treatment.

This study presents the synthesis, characterization, and application of multifunctional PAMAM G2 and G4 dendrimers decorated with a linear fluorinated guanidino linker designed to improve gene delivery efficiency while minimizing cytotoxicity. For the first time, we were able to fine-tune the degree of grafting (DG) during the functionalization process through efficient "click" Michael addition, achieving the synthesis of a collection of six PAMAM conjugates that showed a significant enhancement in transfection efficiency (TE), surpassing the performance of traditional nonviral vectors. The incorporation of fluorinated moieties not only facilitated better deoxyribonucleic acid (DNA) condensation and TE but also introduced potential applications in ¹⁹F magnetic resonance imaging thanks to the sharp and intense fluorine nuclear magnetic resonance signals and favorable relaxation parameters. The new dendrimer conjugates demonstrated a promising balance between low cytotoxicity and high TE, with the low-generation PAMAM G2 with lower DG being the best-performing conjugate, making them strong candidates for further development in gene therapy. These findings highlight the potential of these multifunctional PAMAM dendrimers as efficient, nontoxic, and trackable gene delivery vectors.

l-Asparaginase (l-ASNase) catalyzes the hydrolysis of l-asparagine, leading to its depletion and subsequent effects on the cellular proliferation and survival. In contrast to normal cells, malignant cells that lack asparagine synthase are extremely susceptible to asparagine deficiency. l-ASNase has been successfully employed in treating pediatric leukemias and non-Hodgkin lymphomas; however, its usage in adult patients and other types of cancer is limited due to significant side effects and drug resistance. Recent research has explored alternative formulations and delivery methods to enhance its efficacy and minimize adverse effects. One promising approach involves the immobilization of l-ASNase onto nanostructured materials, offering improved enzymatic activity and biocompatibility of the support. We harnessed an E. coli l-ASNase type II preparation to develop a novel strategy of enzyme immobilization on graphene oxide (GO)-based support. We compared GO and nanographene oxide (nGO) in terms of their biocompatibility and influence on enzyme parameters. The obtained l-ASNase on the nGO nanobiocatalyst maintains enzymatic activity and increases its stability, selectively acting on K562 leukemia cells without cytotoxic influence on normal endothelial cells. In the case of treated K562 cells, we confirmed enlargement in the cell and nucleus size, disturbance in the cell cycle (interphase and metaphase), and increased apoptosis rate. The potential therapeutic possibilities of immobilized l-ASNase on leukemia cell damage are also discussed, highlighting the importance of further research in this area for advancing cancer therapy.

Herein, a water-soluble, ultrabright, near-infrared (NIR) fluorescent, mechanically interlocked molecules (MIMs)-peptide bioconjugate is designed with dual targeting capabilities. Cancer cell surface overexpressed α_Vβ₃ integrin targeting two RGDS tetrapeptide residues is tethered at the macrocycle of MIMs-peptide bioconjugate via Cu(I)-catalyzed click chemistry on the Wang resin, and mitochondria targeting lipophilic cationic TPP⁺ functionality is conjugated at the axle dye. Living carcinoma cell selective active targeting, subsequently cell penetration, mitochondrial imaging, including the ultrastructure of cristae, and real-time tracking of malignant mitochondria by MIMs-peptide bioconjugate (RGDS)₂-Mito-MIMs-TPP⁺ are established by stimulated emission depletion (STED) super-resolved fluorescence microscopy. Water-soluble NIR (RGDS)₂-Mito-MIMs-TPP⁺ is an effective class of MIMs-peptide bioconjugate with promising photophysics; for instance, remarkable photostability and thermal stability, strong and narrow NIR abs/em bands with high quantum yield, ultrabrightness, decent fluorescence lifetime, reasonable stability against cellular nucleophiles, biocompatibility, noncytotoxicity, and dual-targeted living cancer cell submitochondrial imaging ability are all indispensable criteria for targeted super-resolved STED microscopy.

ENPP-1 is a transmembrane enzyme involved in nucleotide metabolism, and its overexpression is associated with various cancers, making it a potential therapeutic target and biomarker for early tumor diagnosis. Current detection methods for ENPP-1 utilize a colorimetric probe, TMP-pNP, which has significant limitations in sensitivity. Here, we present probe CL-ENPP-1, the first nucleic acid-based chemiluminescent probe designed for rapid and highly sensitive detection of ENPP-1 activity. The design of probe CL-ENPP-1 features a phenoxy-adamantyl-1,2-dioxetane luminophore linked to thymidine via a phosphodiesteric bond. Upon cleavage of the enzymatic substrate by ENPP-1, the probe undergoes an efficient chemiexcitation process to emit a green photon. Probe CL-ENPP-1 demonstrates an exceptional signal-to-noise ratio of 15000 and a limit of detection value approximately 4500-fold lower than the widely used colorimetric probe TMP-pNP. A comparison of TMP-pNP activation by ENPP-1 versus alkaline phosphatase (ALP) reveals a complete lack of selectivity. Removal of the self-immolative spacer from probe CL-ENPP-1 resulted in a new chemiluminescent probe, CL-ENPP-2, with an 18.4-fold increase in selectivity for ENPP-1 over ALP. The ability of probe CL-ENPP-2 to detect ENPP-1 activity in mammalian cells was assessed using the human breast cancer cell line MDA-MB-231. This probe demonstrated a 19.5-fold improvement in the signal-to-noise ratio, highlighting its superior ability to detect ENPP-1 activity in a biological sample. As far as we know, to date, CL-ENPP-1 and CL-ENPP-2 are the most sensitive probes for the detection of ENPP-1 catalytic activity. We anticipate that our new chemiluminescent probes will be valuable for various applications requiring ENPP-1 detection, including enzyme inhibitor-based drug discovery assays. The insights gained from our probe design principles could advance the development of more selective probes for ENPP-1 and contribute to future innovations in chemiluminescence research.