Search

With increasing interest in applying recombinant monoclonal antibodies (mAbs) in human medicine, engineered mAb fragments with reduced size and improved stability are in demand to overcome current limitations in clinical use. Herein, a novel Fab‐like antibody fragment generated via an in silico‐based engineering approach where the CH1 and CL domains of Fab are replaced by the IgG1 CH3 domains is described. This construct, designated as FabCH3, maintains the natural N‐terminus and C‐terminus of IgG antibody, can be expressed at a high level in bacterial cells and, importantly, exhibits much higher stability and affinity than the parental Fab when tested in a mesothelin‐specific Fab m912, as well as a vascular endothelial growth factor A (VEGFA)‐specific Fab Ranibizumab (in vivo). The high‐resolution crystal structures of m912 FabCH3 and m912 Fab are determined, and the comparative analysis reveals more rigid structures in both constant domains and complementarity‐determining regions of FabCH3, explaining its enhanced stability and affinity. Overall, the stabilized FabCH3 described in this report provides a versatile platform for engineering Fab‐like antibody fragments with higher stability and antigen‐binding affinity that can be used as a distinct class of antibody therapeutics. [ABSTRACT FROM AUTHOR]

Nanotechnology-based photothermal therapy has attracted great attention in the past decade. Nevertheless, photothermal therapy has some inherent drawbacks, such as the uneven heat production and limited laser penetration, often leading to insufficient treatment outcomes. Here, we developed a combination strategy to improve cancer therapy. The biomimetic albumin-modified gold nanorods (AuNRs) were prepared with incorporation of paclitaxel (PTX). This therapeutic system was characterized by several features. First, the albumin modification enhanced the biocompatibility and colloidal stability. Second, the surface-coated albumin promoted cellular uptake via the albumin-binding protein pathway. Third, PTX was incorporated via hydrophobic interaction between PTX and the albumin lipophilic domain. Fourth, the system can be used for combined photothermo-chemotherapy for yielding synergistic effects. The antitumor activity of the system was evaluated both in vitro and in vivo using the HCT116 colon cancer cell and tumor model. The combination therapy was found with an enhanced treatment efficiency and no obvious side effect. Most importantly, the thermal effect was also discovered with the ability to modulate the tumor microenvironments and suppress the macrophages polarization towards the M2 pro-tumor phenotype. It could be a mechanism for photothermal immunotherapy. The combination strategy and the system provide a potential method for cancer therapy. [ABSTRACT FROM AUTHOR]

Multidrug resistance (MDR) is an issue that is not only related to cancer cells but also associated with the tumor microenvironments. MDR involves the complicated cancer cellular events and the crosstalk between cancer cells and their surroundings. Ideally, an effective system against MDR cancer should take dual action on both cancer cells and tumor microenvironments. The authors find that both the drug-resistant colon cancer cells and the protumor M2 macrophages highly express two nutrient transporters, i.e., secreted protein acidic and rich in cysteine (SPARC) and mannose receptors (MR). By targeting SPARC and MR, a system can act on both cancer cells and M2 macrophages. Herein the authors develop a mannosylated albumin nanoparticles with coencapsulation of different drugs, i.e., disulfiram/copper complex (DSF/Cu) and regorafenib (Rego). The results show that combination therapy of DSF/Cu and Rego efficiently inhibits the growth of drug-resistant colon tumor, and the combination has not been reported yet for use in anticancer treatment. The system significantly improves the treatment outcomes in the animal model bearing drug-resistant tumors. The therapeutic mechanisms involve enhanced apoptosis, upregulation of intracellular ROS, anti-angiogenesis, and tumor-associated macrophage 're-education.' This strategy is characterized by dual targeting to and the simultaneous action on cancer cells and M2 macrophages, with biomimetic codelivery of a novel drug combination. [ABSTRACT FROM AUTHOR]

Dual-Targeting to Cancer Cells and M2 Macrophages via Biomimetic Delivery of Mannosylated Albumin Nanoparticles for Drug-Resistant Cancer Therapy GLO:OKZ/20apr20:adfm201910144-fig-0001.jpg PHOTO (COLOR): 8 In vivo imaging of NPs biodistribution in mice bearing HCT8/ADR subcutaneous xenograft tumors. D) Imaging of tumors dissected from the mice. [Extracted from the article]

A complicated mechanistic interaction exists between cancer cells and tumor microenvironments. In article number 1700403, Yongzhuo Huang and co‐workers describe a “one‐stone‐two‐birds” strategy, which uses a mannosylated albumin nanoparticulate co‐delivery system to dual‐target cancer cells and M2 macrophages via the pathways of both mannose receptors and the albumin‐binding protein SPARC. This results in M2 macrophage modulation and enhanced cytotoxicity. [ABSTRACT FROM AUTHOR]

Background: Various tumors are insensitive to immune checkpoint blockade (ICB) therapy. Toll-like receptors (TLRs) establish the link between innate and adaptive immunity, which can assist T-cell activation and serve as promising targets for combination to enhance ICB therapy. Here, we aimed to improve efficacy for anti-programmed death ligand 1 (PD-L1) therapy by developing a PD-L1/TLR7 dual-targeting nanobody-drug conjugate (NDC), based on the PD-L1 nanobodies and TLR7 agonist we developed., Methods: PD-L1 nanobodies were obtained by phage display screening and identified through T-cell activation bioassay, in vivo imaging and quantitative biodistribution study. Immune activation and PD-L1-inducing of TLR7 agonists were evaluated in diverse innate cell models. We constructed PD-L1/TLR7 dual-targeting NDCs by chemically coupling PD-L1 nanobodies and TLR7 agonists. The antitumor effect was evaluated via several murine or humanized solid tumor models. Immunophenotyping, immune cell depletion, tumor rechallenge, RNA sequencing and PD-L1-deficient models were combined to determine the mechanism for NDCs function. The dynamics of the in vivo behaviors of NDCs were assessed based on multiorgan changes in PD-L1 levels., Results: The screened PD-L1 nanobodies were characterized as tumor-targeting and alleviated T-cell immunosuppression. The TLR7 agonists induced broad innate immune responses and intratumoral PD-L1 expression on antigen-presenting cells (APCs), and its antitumor effect was dependent on intratumoral delivery. The combination of TLR7 agonists and PD-L1 nanobodies activated both innate and adaptive immunity and upregulated PD-L1-related signaling pathways. After coupling to form dual-targeting NDCs, TLR7 agonists and PD-L1 nanobodies exerted synergistic antitumor effects and safety in either 'hot' or 'cold' tumor and early or advanced tumor models, reshaped the tumor immune microenvironment and induced antitumor immune memory. CD8 + T cells and natural killer cells were the main effector cells for NDCs to function. NDCs can promote PD-L1 expression on intratumoral APCs and tumor cells, and subsequently achieve targeted enrichment in tumors. Moreover, the efficacy of NDCs is biased toward dependence on host expression of PD-L1., Conclusions: The novel PD-L1/TLR7 dual-targeting NDC exhibited potent efficacy against heterogeneous tumors through orchestrating innate and adaptive immunity, which could act as a promising strategy to improve ICB therapy and shows prospects for clinical development., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Hepatitis B virus (HBV) infection is a serious global health issue with more than 250 million chronic carriers. It causes liver diseases such as chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). Persistent suppression of the HBV surface antigen (HBsAg) is necessary for a functional cure of chronic hepatitis B (CHB) virus infection. However, this can hardly be achieved with currently approved drugs. Antibody treatment against HBsAg has shown promise in restoring HBV-specific immune responses and promoting HBV cure. To achieve long-lasting HBsAg suppression, we used an advanced mRNA drug to encode the genes of three anti-HBsAg antibodies, G12-scFv, G12-scFv-Fc, and G12-IgG. Antibody-encoding mRNA-lipid nanoparticles (LNPs), mL (G12-scFv-Fc) and mL (G12-IgG), substantially reduced serum HBsAg levels in treated mice within 30 days after a single dose. In contrast, exogenous antibodies lost effect on reducing HBsAg or HBV DNA levels 9 days postadministration. The high affinity of anti-HBsAg antibodies and the adjuvant activity of mRNA-LNPs resulted in long-term HBsAg seroclearance, which could contribute to the reestablishment of the immune system in HBV carriers. These findings highlight the great potential of antibody-encoding mRNA molecules against CHB infection. IMPORTANCE It is the first time that mRNA-LNPs have been used to express anti-HBsAg antibodies (G12-scFv, G12-scFv-Fc, and G12-IgG). G12-scFv-Fc- and G12-IgG-encoding mRNA-LNPs exerted a sustained effect on HBsAg serum clearance in the adeno-associated virus (AAV)/HBV mouse model with persistent HBsAg expression. These findings may provide a new design of combination therapy for functional cure of HBV. For example, this strategy could provide an alternative for antibodies in "sandwich" therapy and further enhance the immunization properties of the therapy. Overall, mRNA therapeutics are promising for treatment of infectious diseases because of their rapid development, economic value, and simplicity.

Gefitinib is a first-line therapy in the EGFR-mutated nonsmall cell lung cancer (NSCLC). However, the development of drug resistance is almost unavoidable, thus leading to an unsustainable regimen. EGFR T790M mutation is the major cause responsible for the molecular-targeting therapy failure in NSCLC. Although the recently approved osimertinib is effective for the EGFR T790M -positive NSCLC, the osimertinib-resistant EGFR mutation is rapidly developed, too. In this study, we proposed a tumor-associated macrophage (TAM) reprogramming strategy for overcoming the EGFR T790M -associated drug resistance via a dual-targeting codelivery system of gefitinib/vorinostat that acted on both TAM with overexpression of mannose receptors and the HER-2 positive NSCLC cells. The trastuzumab-modified, mannosylated liposomal system was able to repolarize the protumor M2 phenotype to the antitumor M1 and cause the elevating ROS in the cancer cells, consequently modulating the intracellular redox balance via ROS/NOX3/MsrA axis. The suppressed MsrA facilitated the EGFR T790M degradation through 790M oxidation by ROS, thus resensitizing the EGFR T790M -positive cells to gefitinib. The dual-targeting codelivery and TAM-reprogramming strategies provided a potential method for rescuing the EGFR T790M -caused resistance to tyrosine kinase inhibitor treatment.