Bioconjugate Chemistry最新文献

Poly(amidoamine) (PAMAM) dendrimers have gained significant attention in various research fields, particularly in medicinal compound delivery. Their versatility lies in their ability to conjugate with functional molecules on their surfaces and encapsulate small molecules, making them suitable for diverse applications. Gallic acid is a potent antioxidant compound that has garnered considerable interest in recent years. Our research aims to investigate if the gallic acid-encapsulated PAMAM dendrimer generations 4 (G4(OH)-Ga) and 5 (G5(OH)-Ga) could enhance radical scavenging, which could potentially slow down the progression of age-related macular degeneration (AMD). Encapsulation of gallic acid in PAMAM dendrimers is a feasible alternative to prevent its degradation and toxicity. In vitro investigation of antioxidant activity was carried out using the DPPH and ABTS radical scavenging assays, as well as the FRAP assay. The IC₅₀ values for DPPH and ABTS assays were determined through nonlinear dose-response curves, correlating the inhibition percentage with the concentration (μg/mL) of the sample and the concentration (μM) of gallic acid within each sample. G4(OH)-Ga and G5(OH)-Ga possess significant antioxidant activities as determined by the DPPH, ABTS, and FRAP assays. Moreover, gallic acid-encapsulated PAMAM dendrimers inhibit H₂O₂-induced reactive oxygen species (ROS) production in the human retinal pigment epithelium ARPE-19 cells, thereby improving antioxidant characteristics and potentially retarding AMD progression caused by ROS. In an evaluation of cell viability of ARPE-19 cells using the MTT assay, G4(OH)-Ga was found to reduce cytotoxic effects on ARPE-19 cells.

Histones react with various aldehyde-containing DNA modifications to form reversible but long-lived DNA-histone cross-links. The investigation of their biochemical effects and repair mechanisms has been impeded due to their reversibility and the lack of methods for synthesizing stable and structure-defined DNA-histone cross-links. Herein, we present a visible-light-driven strategy to install an aminooxyhomolysine on a histone at a defined position. Using this method, we synthesized a hydrolytically stable and site-specific 3'-DNA-histone cross-link derived from an abasic DNA lesion. Such an adduct can be efficiently repaired by proteolysis coupled with nuclease excision. This work provides a strategy that can be readily expanded to synthesize DNA-histone cross-links derived from other aldehyde-containing DNA modifications.

Multiple myeloma (MM) is an incurable disease characterized by its clinical and prognostic heterogeneity. Despite conventional chemotherapy and autologous hematopoietic stem cell transplantation, the management of relapsed and refractory MM disease poses significant challenges, both medically and socioeconomically. CD38, highly expressed on the surface of MM cells, serves as a distinct tumor biological target in MM. Peptides offer advantages over antibodies, enabling precise tumor imaging and facilitating early tumor diagnosis and dynamic immunotherapy monitoring. In this study, we developed PF381, a CD38-targeted peptide, and investigated its role in diagnosis, biodistribution, and dosimetry through ⁶⁸Ga-labeling for preclinical evaluation in tumor-bearing models. We screened a microchip-based combinatorial chemistry peptide library to obtain the amino acid sequence of PF381. Affinity for human CD38 was evaluated by SPRi. PF381 was conjugated with DOTA for radiolabeling with ⁶⁸Ga, and the complex was characterized by HPLC. PET imaging was performed in murine tumor models after the administration of [⁶⁸Ga]Ga-DOTA-PF381. Biodistribution analysis compared CD38-positive H929 and CD38-negative U266 tumors, and human radiation dosimetry was estimated. Tumor sections were stained for CD38 expression. SPRi showed that PF381 had a high affinity for CD38 with a KD of 2.49 × 10^-8 M. HPLC measured a radiolabeling efficiency of 78.45 ± 7.91% for [⁶⁸Ga]Ga-DOTA-PF381, with >98% radiochemical purity. PET imaging revealed rapid and persistent accumulation of radioactivity in CD38-positive H929 tumors, contrasting with negligible uptake in CD38-negative U266 tumors. Biodistribution confirmed higher uptake in H929 tumors (0.75 ± 0.03%ID/g) vs U266 (0.26 ± 0.08%ID/g, P < 0.001). The kidney received the highest radiation dose (3.57 × 10^-02 mSv/MBq), with an effective dose of 1.41 × 10^-02 mSv/MBq. Immunofluorescence imaging supported PET and biodistribution findings. We developed a novel peptide targeting CD38 and proved that ⁶⁸Ga-labeled PF381 had rapid targeting and good tumor penetration capabilities. Therefore, ⁶⁸Ga-labeled PF381 could achieve high sensitivity in vivo imaging for CD38-positive hematological malignancies.

Plectin, a scaffolding protein overexpressed in tumor cells, plays a significant role in hepatocellular carcinoma (HCC) proliferation, invasion, and migration. However, the use of L-type peptides for targeting plectin is hindered by their limited stability and retention. We designed a D-type plectin-targeting peptide (^DPTP) and developed a novel single-photon emission computed tomography (SPECT) probe for HCC imaging. The ^DPTP targeting ability was evaluated in vitro using flow cytometry and ex vivo fluorescence imaging. ^99mTc radiolabeling was performed using tricine and ethylenediamine-N,N'-diacetic acid (EDDA) as coligands after modification with 6-hydrazino nicotinamide (HYNIC) at the N termini of ^DPTP. The radiochemical purity (RCP), in vitro stability, and binding affinity of the prepared ^99mTc-HYNIC-^DPTP were analyzed. Tumor uptake, metabolic stability, biodistribution, and pharmacokinetics of ^99mTc-HYNIC-^DPTP were investigated and compared with those of ^99mTc-labeled L-type PTP (^99mTc-HYNIC-PTP) in HCC tumor-bearing mice. ^DPTP could be efficiently radiolabeled with ^99mTc using the HYNIC/tricine/EDDA system with a high RCP and good in vitro stability. Compared with the L-type PTP, ^DPTP exhibited improved targeting ability, and ^99mTc-HYNIC-^DPTP displayed higher tumor uptake, better metabolic stability, longer blood circulation time, and lower kidney retention, resulting in superior imaging performance and biodistribution in vivo. ^99mTc-HYNIC-^DPTP has great potential as a novel SPECT probe for diagnosing HCC.

ATP (adenosine triphosphate) and HMGB1 (high mobility group box 1 protein) are key players in treatments that induce immunogenic cell death (ICD). However, conventional therapies, including radiotherapy, are often insufficient to induce ICD. In this study, we explore a strategy using nanoparticle-loaded macrophages as a source of ATP and HMGB1 to complement radiation-induced intrinsic and adaptive immune responses. To this end, we tested three inorganic particles, namely, iron oxide nanoparticles (ION), aluminum oxide nanoparticles (AON), and zinc oxide nanoparticles (ZON), in vitro with bone marrow-derived dendritic cells (BMDCs) and then in vivo in syngeneic tumor models. Our results showed that ION was the most effective of the three nanoparticles in promoting the secretion of ATP and HMGB1 from macrophages without negatively affecting macrophage survival. Secretions from ION-loaded macrophages can activate BMDCs. Intratumoral injection of ION-loaded macrophages significantly enhanced tumor infiltration and activation of dendritic cells and cytotoxic T cells. Moreover, exogenous ION macrophages can enhance the efficacy of radiotherapy. In addition, direct injection of ION can also enhance the efficacy of radiotherapy, which is attributed to ION uptake by and stimulation of endogenous macrophages. Instead of directly targeting cancer cells, our strategy targets macrophages and uses them as a secretory source of ATP and HMGB1 to enhance radiation-induced ICD. Our research introduces a new nanoparticle-based immunomodulatory approach that may have applications in radiotherapy and beyond.

The Wnt signaling pathway has a significant regulatory part in tissue development and homeostasis. Dysregulation of the Wnt signaling pathway has been associated with many diseases including cancers and various brain diseases, making this signaling pathway a promising therapeutic target for these diseases. In this review, we describe the roles of the Wnt signaling pathway in the blood-brain barrier (BBB) in intracranial tumors and peripheral tumors, from preclinical and clinical perspectives, introduce Wnt-regulated therapeutics including various types of drugs and nanomedicines as BBB modulators for brain-oriented drug delivery and as therapeutic drugs for cancer treatments, and finally discuss limitations and future perspectives for Wnt-regulated therapeutics.

Cancer-associated fibroblasts (CAFs) expressing fibroblast activation protein alpha (FAP) are abundant in tumor microenvironments and represent an emerging target for PET cancer imaging. While different quinolone-based small molecule agents have been developed for whole-body imaging, there is a scarcity of well-validated fluorescent small molecule imaging agents to better study these cells in vivo. Here, we report the synthesis and characterization of a series of fluorescent FAP imaging agents based on the common quinolone azide inhibitor. Our data show excellent performance of some synthesized FAP Targeting Fluorescent probes (FTFs) for both topical application and intravenous delivery to label CAF populations in solid tumors. These results suggest that FTF can be used to study CAF biology and therapeutic targeting in vivo.

Ionizable cationic lipids have been developed to mitigate the toxicity of quaternary ammonium lipids, such as DOTAP. Despite its toxicity, DOTAP can promote localization of lipid nanoparticles (LNPs) in target tissues, serving as one of the ionizable cationic helper lipids. Notably, DOTAP-based nanoadjuvants prepared via microfluidic methods showed a better T-cell response. Previous studies showed that DOTAP-based LNPs prepared by the lipid-film method resulted in obvious adverse events. Therefore, our research focused on evaluating the tissue localization and adverse toxicity of a DOTAP-based delivery system prepared through microfluidic techniques. We assessed the delivery efficacy, biodistribution, inflammatory response, and pathological injury in various tissues. In our study, the plasmid DNA encoding the receptor-binding domain (RBD) of SARS-CoV-2 was encapsulated using a mixture of lipids that included DOTAP, DOPE, cholesterol, and DMG-PEG2000 via microfluidic mixing. The LNP-RBDs were smaller than those prepared via the traditional lipid membrane system. We found that LNP-DNA complexes can be effectively delivered and expressed in muscle tissue, with specific antibodies in serum induced postimmunization. Initial distribution of the liposomes was observed in the muscle and liver. Interestingly, both LNPs and DNA showed sustained presence in the lungs and spleen in the group immunized with DNA-encapsulated DOTAP-based LNPs, whereas lower amounts of DNA were detected in the group immunized with dissociative DNA. We detected obvious inflammatory responses and pathological injuries in the muscle, heart, and liver, and the side effects decreased when the immunization dose decreased. These findings suggest that DOTAP-based LNPs have obvious advantages for targeting the lungs and spleen. Additionally, inflammatory responses and pathological injuries occur in a dose-dependent manner in the muscles, heart, and liver. In conclusion, these findings contribute to the development of an LNP delivery system with DOTAP, highlighting its potential to enhance tissue localization and promote high levels of expression when coordinated with ionizable lipids.

Poly(amidoamine) (PAMAM) dendrimers have gained significant attention in various research fields, particularly in medicinal compound delivery. Their versatility lies in their ability to conjugate with functional molecules on their surfaces and encapsulate small molecules, making them suitable for diverse applications. Gallic acid is a potent antioxidant compound that has garnered considerable interest in recent years. Our research aims to investigate if the gallic acid-encapsulated PAMAM dendrimer generations 4 (G4(OH)-Ga) and 5 (G5(OH)-Ga) could enhance radical scavenging, which could potentially slow down the progression of age-related macular degeneration (AMD). Encapsulation of gallic acid in PAMAM dendrimers is a feasible alternative to prevent its degradation and toxicity. In vitro investigation of antioxidant activity was carried out using the DPPH and ABTS radical scavenging assays, as well as the FRAP assay. The IC₅₀ values for DPPH and ABTS assays were determined through nonlinear dose–response curves, correlating the inhibition percentage with the concentration (μg/mL) of the sample and the concentration (μM) of gallic acid within each sample. G4(OH)-Ga and G5(OH)-Ga possess significant antioxidant activities as determined by the DPPH, ABTS, and FRAP assays. Moreover, gallic acid-encapsulated PAMAM dendrimers inhibit H₂O₂-induced reactive oxygen species (ROS) production in the human retinal pigment epithelium ARPE-19 cells, thereby improving antioxidant characteristics and potentially retarding AMD progression caused by ROS. In an evaluation of cell viability of ARPE-19 cells using the MTT assay, G4(OH)-Ga was found to reduce cytotoxic effects on ARPE-19 cells.