Molecular Pharmaceutics最新文献

Renal fibrosis, a central pathological feature in chronic kidney disease progression, is marked by aberrant myofibroblast activation and excessive extracellular matrix deposition. Currently, no effective therapies are available to reverse this condition. Although celastrol (CEL) exhibits potent antifibrotic activity, its clinical application is hindered by poor solubility and significant systemic toxicity. To overcome these limitations, we developed a CD44-targeted and reactive oxygen species (ROS)-responsive nanoparticle (CEL@CB) for targeted renal delivery. The nanoparticle was constructed by conjugating bilirubin (BR) to chondroitin sulfate (CS), creating an amphiphilic CS-BR conjugate that self-assembles into nanoparticles capable of encapsulating CEL. The CS shell enables active targeting of CD44 receptors, which are highly overexpressed on activated renal myofibroblasts, while the BR core responds to elevated ROS levels in fibrotic kidneys, triggering drug release and simultaneously scavenging ROS to alleviate inflammation. Both in vitro and in vivo studies demonstrated that CEL@CB nanoparticles facilitate targeted CEL delivery to activated myofibroblasts, achieving a drug accumulation in fibrotic kidneys more than 2-fold higher than in healthy controls. Treatment with CEL@CB reduced the expression of key fibrotic markers (α-SMA and Col1a1) by approximately 30−70% at both mRNA and protein levels and decreased serum creatinine and blood urea nitrogen (BUN) levels by about 50%, thereby significantly attenuating folic acid-induced renal fibrosis, restoring renal function, and mitigating histological damage. Importantly, this targeted strategy markedly minimized the toxicity to the heart, testis, and hematological systems associated with free CEL. This dual-functional nanoparticle combines CD44-mediated renal targeted delivery with ROS-responsive drug release, offering a novel approach for antifibrotic therapy.

To enhance the therapeutic efficacy of breast cancer, multimodal therapy with the aid of a pH-responsive controlled release platform is proposed in this work. Indocyanine green (ICG) is loaded in honeycomb MnO₂ (hMnO₂) synthesized by a template method, which is coencapsulated with 5-fluorouracil (5-FU) in the hydrogels cross-linked between carboxymethyl chitosan (CMCS) and oxidized hyaluronic acid (OHA). The imine linkage (−HC═N−) between CMCS and OHA is hydrolyzed under weakly acidic conditions, leading to the release of 5-FU for chemotherapy and ICG/hMnO₂. The hMnO₂ can convert the optical energy of near-infrared (NIR) light into heat for photothermal therapy (PTT). Additionally, the hMnO₂ can be reduced to Mn²⁺ at low pH and high glutathione (GSH) level, and the produced Mn²⁺ can further react with H₂O₂ to generate hydroxyl radicals (·OH) through a Fenton-like reaction for chemodynamic therapy (CDT). ICG can be simultaneously released during the reduction of hMnO₂, which can catalyze the conversion of oxygen to singlet oxygen (¹O₂) upon exposure to NIR light for photodynamic therapy (PDT). Due to the synergistic effects of chemotherapy, PTT, CDT, and PDT, the developed ICG/hMnO₂/5-FU/CMCS/OHA hydrogels can significantly inhibit the growth of the 4T1 mouse breast cancer cell line.

Gastrin-releasing peptide receptor (GRPR) is a G-protein-coupled receptor that is overexpressed in several malignancies, rendering it an ideal target for cancer imaging and therapy. In this report, we conducted structure–activity relationship studies by optimizing the substitution of Pro¹⁴ based on an agonist sequence, [d-Phe⁶,Pro¹⁴]Bombesin(6–14), and optimizing the substitution of the C-terminal Leu¹³-NH² based on an antagonist sequence, [d-Phe⁶,des-Met¹⁴]Bombesin(6–14). PEP-1–PEP-5 derived from the agonist sequence and PEP-6–PEP-14 derived from the antagonist sequence were synthesized by a solid-phase approach and were obtained in 10–60% yield. In vitro competition binding assays showed that the K_i values of PEP-1–PEP-14 were in the range of 1.16 nM to 266 nM. PEP-3, PEP-4, PEP-8, PEP-9, and PEP-10 with K_i < 6 nM were selected for elongation with Ga-DOTA complex and Pip linker at their N-terminus. Calcium release assays confirmed the agonist-antagonist nature of Ga-DOTA-Pip-conjugated peptides. Ga-DOTA-Pip-PEP-4, Ga-DOTA-Pip-PEP-9, and Ga-DOTA-Pip-PEP-10 retaining high GRPR binding affinity (K_i < 10 nM) were selected for ⁶⁸Ga labeling for further evaluation. [⁶⁸Ga]Ga-DOTA-Pip-PEP-4, [⁶⁸Ga]Ga-DOTA-Pip-PEP-9, and [⁶⁸Ga]Ga-DOTA-Pip-PEP-10 were obtained in 16–44% decay-corrected radiochemical yields with ≥64 GBq/μmol molar activity and ≥ 97% radiochemical purity. PET imaging and ex vivo biodistribution studies were conducted in PC-3 tumor-bearing mice at 1 h postinjection. All [⁶⁸Ga]Ga-DOTA-Pip-PEP-4, [⁶⁸Ga]Ga-DOTA-Pip-PEP-9, and [⁶⁸Ga]Ga-DOTA-Pip-PEP-10 were excreted mainly via the renal pathway and enabled clear visualization of tumor xenografts in PET images with good tumor-to-background contrast. The pancreas uptake of the agonist tracer, [⁶⁸Ga]Ga-DOTA-Pip-PEP-4, was much lower than that of the clinically evaluated agonist tracer, [⁶⁸Ga]Ga-AMBA. Similarly, the pancreas uptake of the antagonist tracers, [⁶⁸Ga]Ga-DOTA-Pip-PEP-9, and [⁶⁸Ga]Ga-DOTA-Pip-PEP-10, was also much lower than that of the clinically evaluated antagonist tracers, [⁶⁸Ga]Ga-RM2, [⁶⁸Ga]Ga-SB3, and [⁶⁸Ga]Ga-NeoB. Our data demonstrate that the sequences of Ga-DOTA-Pip-PEP-4, Ga-DOTA-Pip-PEP-9, and Ga-DOTA-Pip-PEP-10 are promising templates for the development of radiopharmaceuticals targeting GRPR-expressing cancer.

In vivo pretargeting offers a strategy to improve nuclear imaging and radiopharmaceutical therapy by increasing tumor-to-background activity concentration ratios and decreasing radiation burden to healthy tissues. One particularly promising approach to in vivo pretargeting is predicated on the inverse electron-demand Diels–Alder (IEDDA) ligation between tetrazine (Tz)-based radioligands and trans-cyclooctene (TCO)-bearing immunoconjugates. Not surprisingly, the performance of such systems is highly dependent upon the pharmacokinetic profiles of the small molecule radioligands. Herein, we report the synthesis and characterization of a trio of sarcophagine-bearing tetrazines─SarAr-Tz, SarAr-PEG₅-Tz, and SarAr-PEG₁₀-Tz─as well as their radiolabeling with copper-64 (⁶⁴Cu, t_1/2 ∼ 12.7 h), a positron-emitting radioisotope of copper. These radioligands were paired with a TCO-bearing variant of the A33 antigen-targeting antibody huA33 (i.e., huA33-TCO) for pretargeted immunoPET in a murine model of colorectal cancer, revealing that all three produced images with excellent tumor-to-background contrast, but [⁶⁴Cu]Cu-SarAr-PEG₁₀-Tz yielded the best tumor-to-tissue activity concentration ratios. In light of its superior performance, SarAr-PEG₁₀-Tz was subsequently radiolabeled with copper-67 (⁶⁷Cu, t_1/2 ∼ 61.8 h), a β^–-emitting radioisotope of copper, to produce [⁶⁷Cu]Cu-SarAr-PEG₁₀-Tz. This radioligand was then paired with huA33-TCO for in vivo biodistribution and longitudinal therapy studies, ultimately revealing that pretargeted radioimmunotherapy with [⁶⁷Cu]Cu-SarAr-PEG₁₀-Tz exhibits promising efficacy and safety in a murine model of colorectal cancer.

Molecular imaging is a useful tool for the in vivo validation of antibody therapeutics. It shows the accumulation properties of antibodies in tumors and organs that cannot be predicted by using in vitro assays. Two issues with characterizing antibodies using in vivo imaging are: (i) the fluorescent signal from the antibody is sensitive to its depth in the tissue, and (ii) there are large biological variabilities observed in in vivo imaging studies. Paired agent imaging measures the fluorescence of a test antibody and a control antibody in the same animal, allowing the fluorescence of the test antibody to be normalized to that of the control antibody. We used paired agent imaging to compare the in vivo imaging properties of two affinity-matured variants of the anti-EGFR antibody nimotuzumab (K4 and K5) to the parental antibody. To perform paired agent imaging, we labeled the test antibodies (K4 and K5) with IRDye800CW and the control antibody (nimotuzumab) labeled with IRDye680RD, and coinjected them into mice bearing EGFR-positive xenografts. Near-infrared fluorescent imaging was used to quantitate the relative amount of each antibody present in tumors and organs. Paired agent imaging allowed us to detect differences in in vivo fluorescence between K4, K5, and nimotuzumab, where K5 had the highest accumulation in the tumor, followed by K4 and nimotuzumab.

Porphyrin-based nanovesicles have emerged as promising platforms for pharmaceutical applications due to their inherent biocompatibility and unique photosensitive properties. Their vesicular architecture facilitates both photodynamic and photothermal therapies while enabling targeted drug delivery through photoactivation. Incorporation of porphyrins into nanovesicle bilayers enhances therapeutic efficacy, stability, and cellular uptake. Moreover, porphyrins’ ability to chelate metal ions extends their use to diagnostic imaging and theranostics. Specifically, cobalt-chelated porphyrin vesicles have demonstrated potential for the targeted delivery of macromolecules, including peptides and vaccines. This review highlights recent advances in the design, modification, and biomedical application of porphyrin-based nanovesicles, with a focus on their chemical versatility and multifunctionality.

Antigen-specific tolerance induction is a promising therapeutic strategy for autoimmune and chronic inflammatory diseases. This can be achieved by targeted activation of regulatory T and B cells via antigen-presenting cells (APCs) in a tolerogenic context. Anionic antigen-carrying liposomes have shown potential; however, their efficacy is highly dependent on the administration route and liposomal composition. Here, we investigate the biodistribution and splenic APC subset-specific uptake of tolerogenic (DSPC:DSPG:CHOL) liposomes compared to inert (DOPC:DOPG:CHOL) liposomes using high-parameter flow cytometry. We developed a panel enabling identification of rare splenic APC subsets involved in immune tolerance, including CD169⁺ and MARCO⁺ marginal zone macrophages, red pulp macrophages, and conventional/plasmacytoid dendritic cells. Our findings confirm that liposomes composed of saturated phospholipids predominantly accumulate in the liver and spleen following an intravenous (IV) injection, with negligible uptake in lymph nodes or lungs. Importantly, systemic distribution is significantly inhibited by subcutaneous (SC) administration, which is essential for tolerance induction. Among splenic APCs, macrophage subsets are major contributors to liposome uptake, though the liver remains the primary site of accumulation and may play a more dominant role in tolerance induction. This study underscores the importance of both liposomal design and delivery route in optimizing nanoparticle-based immune modulation strategies.

Multiple myeloma (MM), the second most common hematologic malignancy, often presents with a gradual onset and minimal symptoms in its early stages, leading to frequent misdiagnosis and delays in treatment. In recent years, radionuclide-based molecular imaging has emerged as a pivotal tool in the noninvasive evaluation and clinical management of MM, particularly in assessing the expression of CD38─a transmembrane glycoprotein that is robustly expressed on approximately 80–100% of malignant plasma cells. Notably, clinical studies have revealed a negative correlation between CD38 expression levels and treatment outcomes, underscoring the importance of accurate and dynamic measurement of CD38 for diagnostic precision and individualized treatment stratification. Radiolabeled molecular imaging targeting CD38 enables repeated, in vivo assessments of its expression status, allowing clinicians to monitor molecular heterogeneity and temporal changes throughout disease progression or therapeutic intervention. To this end, a variety of CD38-targeted imaging agents have been developed, including monoclonal antibodies, antibody fragments, nanobodies and peptide. Many of these probes are currently undergoing preclinical evaluation or have entered early phase clinical trials. This review summarizes recent advances in the development and application of CD38-targeted molecular imaging probes in MM, highlighting their potential to improve disease characterization, therapeutic monitoring, and personalized management strategies.

Antibody-based zirconium-89 (⁸⁹Zr)-containing immunological positron emission tomography (immuno-PET) agents have applications in high-precision cancer imaging. These agents require a bifunctional chelator to bind the positron-emitting ⁸⁹Zr isotope and facilitate the covalent attachment to a cancer-targeting monoclonal antibody (mAb). The hexadentate hydroxamic acid chelator desferrioxamine B (DFO) is commonly used in the development of ⁸⁹Zr-immunoPET agents. While DFO is efficiently radiolabeled with ⁸⁹Zr, vacancies in the unsaturated ⁸⁹Zr-DFO coordination sphere can reduce the ⁸⁹Zr-DFO complex stability and increase the risk of ⁸⁹Zr dissociating and accumulating in nontarget tissues, particularly bone. This potential shortcoming of ⁸⁹Zr-DFO can be addressed by using an octadentate chelator to fully saturate the ⁸⁹Zr coordination sphere. The octadentate chain-extended DFO analogue DFO* was the first exemplar of this class and showed ⁸⁹Zr-DFO* was more stable than ⁸⁹Zr-DFO. The current work designed, synthesized, and evaluated the properties of a new octadentate DFO analogue, named D8W, where “W” designates “water-soluble”. This property has been built into D8W by including water-solubilizing ether oxygen atoms in the hydroxamic acid extension unit appended to DFO and a PEG₄ unit. Comparison of the two most water-soluble chelators from the set of DFO, DFO* and D8W, showed that compared to [⁸⁹Zr]Zr-DFO-mAb (mAb = Girentuximab), [⁸⁹Zr]Zr-D8W-mAb had improved ⁸⁹Zr radiolabeling kinetics and in vitro stability. Key to its utility, bone deposition of ⁸⁹Zr was lower for [⁸⁹Zr]Zr-D8W-mAb than [⁸⁹Zr]Zr-DFO-mAb, as assessed by PET imaging in a CAIX-expressing HT-29 tumor-bearing Balb/C nude mouse model. The performance of D8W coupled with its water solubility supports its merit in its use in ⁸⁹Zr-immunoPET agents.

High neurotensin receptor 1 (NTSR1) expression is strongly associated with progression and poor prognosis across multiple malignancies. We designed an NTSR1-targeted peptide-based PET probe conjugated with the albumin-binding moiety ibuprofen, designated [⁶⁸Ga]Ga-DOTA-NT-20.3-Ibu, which was synthesized with high radiochemical yield and purity, exhibited sufficient in vitro stability, and demonstrated favorable serum albumin-binding capacity. Cell binding/uptake assays, animal-based PET imaging, and biodistribution studies confirmed the radiotracer’s high affinity and specificity for NTSR1. In human participants, [⁶⁸Ga]Ga-DOTA-NT-20.3-Ibu was safe and primarily excreted via the urinary system. Bone marrow uptake was detectable with SUVmean of 4.11 ± 1.59 and 4.99 ± 1.82 at 60 and 120 min postinjection, respectively. Mild uptake was observed in the blood pool, liver, spleen, pancreas, stomach, and bowel, while other tissues showed minimal uptake. Importantly, lung tumor uptake of [⁶⁸Ga]Ga-DOTA-NT-20.3-Ibu correlated with NTSR1 expression levels. Collectively, [⁶⁸Ga]Ga-DOTA-NT-20.3-Ibu PET enables accurate, noninvasive assessment of tumor NTSR1 expression, facilitating NTSR1-targeted cancer treatment and prognosis monitoring.