Search

As a new alternative to antibody-drug conjugates, we developed "ligand-targeting" peptide-drug conjugates (PDCs), in which conformationally constrained helix-loop-helix (HLH) peptide M49 targeting human vascular endothelial growth factor-A (VEGF) was used as a drug carrier. The biochemical study showed that HLH peptide M49 made a complex with VEGF in the extracellular environment, and then the M49/VEGF complex interacts with the receptor on the cell surface to induce cellular internalization via the endocytic pathway. Here, we present an X-ray crystal structure of the M49/VEGF complex at 1.5 Å resolution using a protein crystal grown in microgravity. The structure illustrated the "ligand-targeting" cellular uptake mechanism for intracellular drug delivery and the molecular basis on the peptide-VEGF binding mode with tight binding and high target specificity. In addition, mutational studies and thermodynamic analysis provided information on the driving forces of the complex formation. This work would contribute to the design of mid-size molecular-targeting peptides as well as HLH peptides, advancing the research in drug discovery and chemical biology., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Co-authors Masayuki Kamo and Koji Inaka are MARUWA Foods and Biosciences, Inc. Employees., (Copyright © 2024. Published by Elsevier Inc.)

At present, mid-sized binding peptides have emerged as a new class of drug modalities. We have de novo designed a helix-loop-helix (HLH) peptide (MW: ∼4,500), constructed phage-displayed libraries, and screened the libraries against a variety of disease-related proteins to successfully obtain molecular-targeting HLH peptides. The next essential step in developing HLH peptides into therapeutics involves affinity engineering to optimize binding affinity and specificity. Here, we demonstrate deep mutational scanning to improve binding affinity over 1000-fold for an HLH peptide (P8-2KA; K D = 380 nM) targeting granulocyte colony-stimulation factor receptor (G-CSFR). Site-saturation mutagenesis on the two helices was performed to produce a phage-displayed library that was screened against G-CSFR. The DNA sequences of mutants from the unselected and selected phage libraries were analyzed with next-generation sequencing. The enrichment ratio of each mutant was calculated from the sequencing data to identify beneficial mutations for G-CSFR binding. Grafting of the five beneficial mutations on P8-2KA dramatically increased the binding affinity (K D = 16 nM), while cyclization of the HLH peptide with an intramolecular disulfide bond further increased binding affinity for G-CSFR (K D = 0.18 nM). The combined strategy of phage-displayed library selection and deep mutational scanning-guided design generated high-affinity HLH peptides, emphasizing the potential of molecular-targeting HLH peptides as a new drug modality that serves as an alternative to antibodies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Mid-sized binding peptides have recently emerged as a new therapeutic modality. A helix-loop-helix (HLH) peptide was designed as a scaffold for combinatorial peptide libraries. We screened the HLH peptide libraries against human vascular endothelial growth factor-A (VEGF) to generate a peptide, VS42-LR3, which inhibited VEGF/receptor interaction and suppressed tumor growth in a murine xenograft model of human colorectal cancer. Here, we report the first crystal structure of the HLH peptide in a complex with VEGF at high resolution using space-grown protein crystals. The X-ray structural analysis revealed that the monomeric VS42-LR3 adopted an HLH structure and bound to VEGF at the VEGF receptor-binding site. Interestingly, from the site-directed mutagenesis, thermodynamic analysis, and molecular dynamic simulations, it turned out that the loop region in the non-interacting surface to VEGF affected the structural rigidity of the whole HLH to increase the binding affinity. These findings provide valuable insights for the design of more structurally stable and higher affinity mid-sized binding peptides as well as HLH peptides, that could play a crucial role in advancing molecular-targeting therapies., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Co-authors MK and KI are employees of MARUWA Foods and Biosciences, Inc., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background/objectives: Elastography increased the diagnostic accuracy of liver fibrosis. However, several challenges persist, including the widespread utilization of equipment, difficulties in measuring certain cases, and the influence of viscosity factors. A rough surface and a blunted hepatic margin have long been acknowledged as valuable characteristics indicative of hepatic fibrosis. The objective of this study was to conduct an image analysis and quantitative assessment of the contour of the sagittal section of the left lobe of the liver., Methods: Between February and October 2020, 486 consecutive outpatients underwent ultrasound examinations at our hospital. A total of 214 images were manually annotated by delineating the liver contour to create annotation images. U-Net was employed for liver segmentation, with the dataset divided into training ( n = 128), testing ( n = 42), and validation ( n = 44) subsets. Additionally, 43 Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) cases with pathology data from between 2015 and 2020 were included. Segmentation was performed using the program developed in the first step. Subsequently, shape analysis was conducted using ImageJ., Results: Liver segmentation exhibited high accuracy, as indicated by Dice loss of 0.044, Intersection over Union of 0.935, and an F score of 0.966. The accuracy of the classification of the liver surface as smooth or rough via ResNet 50 was 84.6%. Image analysis showed MinFeret and Minor correlated with liver fibrosis stage ( p = 0.046, 0.036, respectively). Sensitivity, specificity, and AUROC of Minor for ≥F3 were 0.571, 0.862, and 0.722, respectively, and F4 were 1, 0.600, and 0.825, respectively., Conclusion: Deep learning segmentation of the sagittal cross-sectional contour of the left lobe of the liver demonstrated commendable accuracy. The roughness of the liver surface was correctly judged by artificial intelligence. Image analysis showed the thickness of the left lobe inversely correlated with liver fibrosis stage.

Although the fecal immunochemical test for hemoglobin (FIT) is a widely used screening test for colorectal cancer, it is not sensitive enough to detect advanced colorectal adenoma. To address this issue, we performed this study to investigate whether combining the FIT and fecal DNA testing of methylated somatostatin (SST) could improve diagnostic performance for advanced colorectal adenoma. We collected feces from 79 healthy subjects with negative results on colonoscopy, 43 patients with non-advanced colorectal adenoma, 117 patients with advanced colorectal adenoma, and 126 patients with colorectal cancer. After fecal DNA was incubated with methylation-sensitive restriction enzymes, SST methylation levels were measured by droplet digital PCR. Using logistic multivariate analysis, we established a prediction formula for detecting colorectal neoplasia and named it the FAMS (FIT, age, methylated SST) index. The diagnostic performance of a single use of FIT for advanced colorectal adenoma showed a sensitivity of 29.1% (34/117) and specificity of 89.3% (109/122). In contrast, the FAMS index showed a sensitivity of 56.4% (66/117) at a similar specificity point of 91.0% (111/122). Furthermore, even at the higher specificity point of 94.3% (115/122), the sensitivity was still higher than that of FIT, reaching 42.7% (50/117). As the FAMS index showed better diagnostic performance for advanced colorectal adenoma than a single use of FIT, the FAMS index could be a promising tool for detecting advanced colorectal adenoma., (© 2024 The Author(s). Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Introduction: As the incidence of gastric cancer (GC) is increasing in East Asia including Japan, a simple blood test for early GC is needed as an alternative to upper gastrointestinal (UGI) endoscopy. We performed this study to address this issue., Methods: We collected serum samples from 319 participants comprising 225 healthy subjects without GC (control group) and 94 patients with early GC (early GC group). After evaluating copy numbers of serum hTERT and methylated RUNX3 (m-RUNX3) using the Combined Restriction Digital PCR (CORD) assay, which we developed, we assessed the diagnostic performance of hTERT and m-RUNX3 for early GC., Results: Serum levels of hTERT and m-RUNX3 were significantly higher in the early GC group than in the control group. The area under the curve (AUC) was 0.89 for hTERT and 0.78 for m-RUNX3. Multivariate logistic regression analysis revealed age, sex, hTERT copy number, and m-RUNX3 copy number to be independent factors for early GC. We then established a prediction formula and named it the ASTEm-R3 (age, sex, hTERT, and m-RUNX3) index. The AUC of the ASTEm-R3 index was 0.93 with a sensitivity of 79.7% and specificity of 91.1%., Conclusion: We demonstrated excellent performance of the ASTEm-R3 index using the CORD assay to detect early GC. This index might be a promising alternative to UGI endoscopy., (© 2024 The Author(s). Published by S. Karger AG, Basel.)

Ciguatera poisoning (CP), caused by ciguatoxins (CTXs), is one of the most common food-borne diseases, affecting more than 50,000 people each year. In most cases, CP are managed with symptomatic and supportive remedies, and no specific treatment has been devised. In this study, toward the development of therapeutic antibodies for CP, we examined to humanize mouse anti-CTX3C antibody 10C9 (m10C9), which exhibited neutralizing activity against ciguatoxin in vitro and in vivo. The complementarity determining regions were grafted onto a human germline sequence with high sequence identity to m10C9, and the backmutations were examined to maintain the binding affinity. The optimized humanized antibody, Opt.h10C9Fab, showed a strong binding affinity to CTX3C with a high affinity (K D  = 19.0 nM), and only two backmutations of Arg L46 and Cys H94 in the framework regions were involved in determining the antigen binding affinity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)