Engineering the Propeptide of Microbial Transglutaminase Zymogen: Enabling Substrate-Dependent Activation for Bioconjugation Applications.

Microbial transglutaminase (MTG) from Streptomyces mobaraensis is a powerful biocatalytic glue for site-specific cross-linking of a range of biomolecules and synthetic molecules that have an MTG-reactive moiety. The preparation of active recombinant MTG requires post-translational proteolytic digestion of a propeptide that functions as an intramolecular chaperone to assist the correct folding of the MTG zymogen (MTGz) in the biosynthesis. Herein, we report engineered active zymogen of MTG (EzMTG) that is expressed in soluble form in the host Escherichia coli cytosol and exhibits cross-linking activity without limited proteolysis of the propeptide. We found that the saturation mutagenesis of residues K10 or Y12 in the propeptide domain generated several active MTGz mutants. In particular, the K10D/Y12G mutant exhibited catalytic activity comparable to that of mature MTG. However, the expression level was low, possibly because of decreased chaperone activity and/or the promiscuous substrate specificity of MTG, which is potentially harmful to the host cells. The K10R/Y12A mutant exhibited specific substrate-dependent reactivity toward peptidyl substrates. Quantitative analysis of the binding affinity of the mutated propeptides to the active site of MTG suggested an inverse relationship between the binding affinity and the catalytic activity of EzMTG. Our proof-of-concept study provides insights into the design of a new biocatalyst using the MTGz as a scaffold and a potential route to high-throughput screening of EzMTG mutants for bioconjugation applications.

Short-term outcomes of preoperative chemotherapy with docetaxel, oxaliplatin, and S-1 for gastric cancer with extensive lymph node metastasis (JCOG1704).

BACKGROUND: The prognosis for marginally resectable gastric cancer with extensive lymph node metastasis (ELM) remains unfavorable, even after R0 resection. To assess the safety and efficacy of preoperative docetaxel, oxaliplatin, and S-1 (DOS), we conducted a multicenter phase II trial. METHODS: Eligibility criteria included histologically proven HER2-negative gastric adenocarcinoma with bulky nodal (bulky N) involvement around major branched arteries or para-aortic node (PAN) metastases. Patients received three cycles of docetaxel (40 mg/m2, day 1), oxaliplatin (100 mg/m2, day 1), and S-1 (80-120 mg/body, days 1-14), followed by gastrectomy with D2 plus PAN dissection. Subsequently, patients underwent postoperative chemotherapy with S-1 for 1 year. The primary endpoint was major (grade ≥ 2a) pathological response rate (pRR) according to the Japanese Classification of Gastric Carcinoma criteria. RESULTS: Between October 2018 and March 2022, 47 patients (bulky N, 20; PAN, 17; both, 10) were enrolled in the trial. One patient was ineligible. Another declined any protocol treatments before initiation. Among the 45 eligible patients who initiated DOS chemotherapy, 44 (98%) completed 3 cycles and 42 (93%) underwent R0 resection. Major pRR and pathological complete response rates among the 46 eligible patients, including the patient who declined treatment, were 57% (26/46) and 24% (11/46), respectively. Common grade 3 or 4 toxicities were neutropenia (24%), anorexia (16%), febrile neutropenia (9%), and diarrhea (9%). No treatment-related deaths occurred. CONCLUSIONS: Preoperative chemotherapy with DOS yielded favorable pathological responses with an acceptable toxicity profile. This multimodal approach is highly promising for treating gastric cancer with ELM.

Risk factors for early recurrence after radical gastrectomy followed by adjuvant chemotherapy for stage II or III gastric cancer: a multicenter, retrospective study.

BACKGROUND: Radical gastrectomy followed by adjuvant chemotherapy is the standard treatment for stage II or III gastric cancer in Asian countries. Early recurrence during or after adjuvant chemotherapy is associated with poor prognosis; however, risk factors for early recurrence remain unclear. METHODS: In this multicenter, retrospective cohort study including six institutions, we evaluated the clinicopathological factors of 553 patients with gastric cancer undergoing gastrectomy followed by adjuvant chemotherapy between 2012 and 2016. Patients were divided into the following groups: early recurrence (recurrence during adjuvant chemotherapy or within 6 months after adjuvant chemotherapy completion) and non-early recurrence, which was further divided into late recurrence and no recurrence. Early-recurrence risk factors were investigated using multivariate Cox proportional hazard model. The chronological changes in the recurrence hazard were also examined for each factor. RESULTS: Early recurrence and late recurrence occurred in 83 (15.0%) and 73 (13.2%) patients, respectively. Based on the Cox proportional hazards model, a postoperative serum carcinoembryonic antigen level of ≥5 ng/mL (hazard ratio: 2.220, 95% confidence interval: 1.089-4.526) and a neutrophil-to-lymphocyte ratio of >1.8 (hazard ratio: 2.408, 95% confidence interval: 1.479-3.92) were identified as independent risk factors of early recurrence, but not late recurrence. The recurrence hazard ratios for neutrophil-to-lymphocyte ratio significantly decreased over time (P < 0.001) and carcinoembryonic antigen also had the same tendency (P = 0.08). CONCLUSIONS: A carcinoembryonic antigen level of ≥5 ng/mL and a neutrophil-to-lymphocyte ratio of >1.8 are predictors of early recurrence after radical gastrectomy and adjuvant chemotherapy for stage II or III gastric cancer.

Exploratory analysis of serum HER2 extracellular domain for HER2 positive gastric cancer treated with SOX plus trastuzumab.

BACKGROUND: The aim of this study was to explore the clinical utility of serum HER2 extracellular domain (sHER2 ECD) using data from a clinical trial evaluating trastuzumab combined S-1 plus oxaliplatin (SOX) in HER2 positive gastric cancer. METHODS: sHER2 ECD were prospectively measured at baseline and subsequent treatment courses. Based on each quantile point of baseline sHER2 ECD levels and its early changes, patients were divided into two groups and compared clinical outcomes. RESULTS: 43 patients were enrolled, and 17 patients (39.5%) were positive for baseline sHER2 ECD. Higher baseline sHER2 ECD levels tended to have lower hazard ratios (HRs). When divided into two groups by baseline sHER2 ECD of 19.1 ng/ml, median progression-free survival (PFS) and overall survival (OS) was longer in the higher group (mPFS: 16.8 vs 8.7 months, p = 0.359. mOS: 35.5 vs 20.6 months, p = 0.270), respectively. After initiation of treatment, sHER2 ECD significantly decreased up until the third cycle. Higher reduction rates of sHER2 ECD within 3 cycles also tended to have lower HRs. When divided into two groups by reduction rate of 42.5%, mPFS and mOS was longer in the higher reduced group (mPFS: 17.2 vs 8.7 months, p = 0.095. mOS: 65.0 vs 17.8 months, p = 0.047), respectively. Furthermore, higher reduction rates could surrogate higher objective response rates (ORR) (ORR: 90% vs 63.2% for 29.5%, p = 0.065. 100% vs 70% for 42.5%, p = 0.085), respectively. CONCLUSIONS: Baseline sHER2 ECD levels and its early decline may be useful biomarkers for SOX plus trastuzumab efficacy in HER2 positive gastric cancer.

Design of Protease-Responsive Antifungal Liposomal Formulation Decorated with a Lipid-Modified Chitin-Binding Domain.

Candida albicans is a prevalent fungal pathogen that displays antibiotic resistance. The polyene antifungal amphotericin B (AmB) has been the gold standard because of its broad antifungal spectra, and its liposomal formulation, AmBisome, has been used widely and clinically in treating fungal infections. Herein, we explored enhancing the antifungal activity of AmBisome by integrating a small chitin-binding domain (LysM) of chitinase A derived from Pteris ryukyuensis. LysM conjugated with a lipid (LysM-lipid) was initially prepared through microbial transglutaminase (MTG)-mediated peptide tag-specific conjugation of LysM with a lipid-peptide substrate. The AmBisome formulation modified with LysM-lipid conjugates had a size distribution that was comparable to the native liposomes but an increased zeta potential, indicating that LysM-lipid conjugates were anchored to AmBisome. LysM-lipid-modified AmBisome exhibited long-term stability at 4 °C while retaining the capacity to bind chitin. Nevertheless, the antifungal efficacy of LysM-lipid-modified AmBisome against C. albicans was modest. We then redesigned a new LysM-lipid conjugate by introducing a peptide linker containing a thrombin digestion (TD) site at the C-terminus of LysM (LysM-TD linker-lipid), thereby facilitating the liberation of the LysM domain from AmBisome upon the addition of thrombin. This new AmBisome formulation anchored with LysM-TD linker-lipid exhibited superior performance in suppressing C. albicans growth in the presence of thrombin compared with the LysM-lipid formulation. These results provide a platform to design stimuli-responsive AmBisome formulations that respond to external environments and thus advance the treatment of pathogenic fungi infections.

Ionic Liquid-Based Immunization Patch for the Transdermal Delivery of Antigens.

Herein, we report a transdermal patch prepared using an ionic liquid-based solid in oil (IL-S/O) nanodispersion and a pressure-sensitive adhesive (PSA) to deliver the macromolecular antigenic protein, ovalbumin (OVA). The IL-S/O nanodispersion and a PSA were first mixed at an equal weight ratio, then coated onto a release liner, and covered with a support film. To evaluate the effect of the PSA, three types of PSAs, DURO-TAK 87-4098, DURO-TAK 87-4287, and DURO-TAK 87-235A, were used to obtain the corresponding IL-S/O patches SP-4098, SP-4287, and SP-235A, respectively. The prepared IL-S/O patches were characterized for surface morphology, viscoelasticity, and moisture content. In vitro skin penetration and in vivo immunization studies of the IL-S/O patches were performed using Yucatan micropig skin and the C57BL/6NJc1 mice model, respectively. The SP-4098 and SP-4287 delivered 5.49-fold and 5.47-fold higher amounts of drug compared with the aqueous formulation. Although both patches delivered a similar amount of drug, SP-4287 was not detached fully from the release liner after 30 days, indicating low stability. Mice immunized with the OVA-containing SP-4098 produced a 10-fold increase in anti-OVA IgG compared with those treated with an aqueous formulation. These findings suggested that the IL-S/O patch may be a good platform for the transdermal delivery of antigen molecules.

First-line pembrolizumab plus chemotherapy for advanced/metastatic esophageal cancer: 1-year extended follow-up in the Japanese subgroup of the phase 3 KEYNOTE-590 study.

BACKGROUND: First-line pembrolizumab plus chemotherapy (pembrolizumab-chemotherapy) demonstrated improved efficacy and a manageable safety profile versus placebo plus chemotherapy (placebo-chemotherapy) in the subgroup analysis of Japanese patients with advanced/metastatic esophageal cancer in KEYNOTE-590 at a median follow-up of 24.4 months. Longer-term data from the Japanese subgroup analysis of KEYNOTE-590 are reported. METHODS: Patients were randomly assigned 1:1 to pembrolizumab 200 mg or placebo every 3 weeks for ≤ 35 cycles plus chemotherapy (cisplatin 80 mg/m2 and 5-fluorouracil 800 mg/m2/day). Endpoints included overall survival (OS) and progression-free survival (PFS; investigator-assessed per RECIST v1.1; dual primary) and safety (secondary). Early tumor shrinkage (ETS) and depth of response (DpR) were assessed post hoc. RESULTS: Overall, 141 patients were enrolled in Japan. As of July 9, 2021, median follow-up was 36.6 months (range, 29.8-45.7). Pembrolizumab-chemotherapy showed a trend toward favorable OS (hazard ratio [HR], 0.70; 95% confidence interval [CI] 0.47-1.03) and PFS (0.57; 0.39-0.83) versus placebo-chemotherapy. In the pembrolizumab-chemotherapy group, patients with ETS ≥ 20% (55/74; 74.3%) versus < 20% (19/74; 25.7%) had favorable OS (HR, 0.23; 95% CI 0.12-0.42) and PFS (0.24; 0.13-0.43). Patients with DpR ≥ 60% (31/74; 41.9%) versus < 60% (43/74; 58.1%) had favorable OS (HR, 0.37; 95% CI 0.20-0.68) and PFS (0.24; 0.13-0.43). Grade 3-5 treatment-related adverse events occurred in 55/74 patients (74.3%) with pembrolizumab-chemotherapy and 41/67 patients (61.2%) with placebo-chemotherapy. CONCLUSIONS: With longer-term follow-up of Japanese patients with advanced/metastatic esophageal cancer, efficacy continued to favor pembrolizumab-chemotherapy compared with placebo-chemotherapy, with no new safety signals observed. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT03189719.

Estimating the phase diagrams of deep eutectic solvents within an extensive chemical space.

Assessing the formation of a deep eutectic solvent (DES) necessitates a solid-liquid equilibrium phase diagram. Yet, many studies focusing on DES applications do not include this diagram because of challenges in measurement, leading to misidentified eutectic points. The present study provides a practical approach for estimating the phase diagram of any binary mixture from the structural information, utilizing machine learning and quantum chemical techniques. The selected machine learning model provides reasonably high accuracy in predicting melting point (R2 = 0.84; RMSE = 40.53 K) and fusion enthalpy (R2 = 0.84; RMSE = 4.96 kJ mol-1) of pure compounds upon evaluation by test data. By pinpointing the eutectic point coordinates within an extensive chemical space, we highlighted the impact of the mole fractions and melting properties on the eutectic temperatures. Molecular dynamics simulations of selected mixtures at the eutectic points emphasized the pivotal role of hydrogen bonds in dictating mixture behavior.

Ionic liquid-mediated ethosome for transdermal delivery of insulin.

Herein, we report ethosome (ET) formulations composed of a safe amount of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC)-based ionic liquid with various concentrations of ethanol as a carrier for the transdermal delivery of a high molecular weight drug, insulin. The Insulin-loaded ET vesicles exhibited long-term stability compared to conventional DMPC ETs, showing significantly higher drug encapsulation efficiency and increased skin permeation ability.

Design and validation of functionalized redox-responsive hydrogel beads for high-throughput screening of antibody-secreting mammalian cells.

Antibody drugs play a vital role in diagnostics and therapy. However, producing antibodies from mammalian cells is challenging owing to cellular heterogeneity, which can be addressed by applying droplet-based microfluidic platforms for high-throughput screening (HTS). Here, we designed an integrated system based on disulfide-bonded redox-responsive hydrogel beads (redox-HBs), which were prepared through enzymatic hydrogelation, to compartmentalize, screen, select, retrieve, and recover selected Chinese hamster ovary (CHO) cells secreting high levels of antibodies. Moreover, redox-HBs were functionalized with protein G as an antibody-binding module to capture antibodies secreted from encapsulated cells. As proof-of-concept, cells co-producing immunoglobulin G (IgG) as the antibody and green fluorescent protein (GFP) as the reporter molecule, denoted as CHO(IgG/GFP), were encapsulated into functionalized redox-HBs. Additionally, antibody-secreting cells were labeled with protein L-conjugated horseradish peroxidase using a tyramide amplification system, enabling fluorescence staining of the antibody captured inside the beads. Redox-HBs were then applied to fluorescence-activated droplet sorting, and selected redox-HBs were degraded by reducing the disulfide bonds to recover the target cells. The results indicated the potential of the developed HTS platform for selecting a single cell viable for biopharmaceutical production.

Risk factors for bleeding complications in patients undergoing extracorporeal cardiopulmonary resuscitation following out-of-hospital cardiac arrest: a secondary analysis of the SAVE-J II study.

BACKGROUND: Bleeding is the most common complication in out-of-hospital cardiac arrest (OHCA) patients receiving extracorporeal cardiopulmonary resuscitation (ECPR). No studies comprehensively described the incidence rate, timing of onset, risk factors, and treatment of bleeding complications in OHCA patients receiving ECPR in a multicenter setting with a large database. This study aimed to analyze the risk factors of bleeding during the first day of admission and to comprehensively describe details of bleeding during hospitalization in patients with OHCA receiving ECPR in the SAVE-J II study database. METHODS: This study was a secondary analysis of the SAVE-J II study, which is a multicenter retrospective registry study from 36 participating institutions in Japan in 2013-2018. Adult OHCA patients who received ECPR were included. The primary outcome was the risk factor of bleeding complications during the first day of admission. The secondary outcomes were the details of bleeding complications and clinical outcomes. RESULTS: A total of 1,632 patients were included. Among these, 361 patients (22.1%) had bleeding complications during hospital stay, which most commonly occurred in cannulation sites (14.3%), followed by bleeding in the retroperitoneum (2.8%), gastrointestinal tract (2.2%), upper airway (1.2%), and mediastinum (1.1%). These bleeding complications developed within two days of admission, and 21.9% of patients required interventional radiology (IVR) or/and surgical interventions for hemostasis. The survival rate at discharge of the bleeding group was 27.4%, and the rate of favorable neurological outcome at discharge was 14.1%. Multivariable logistic regression analysis showed that the platelet count (< 10 × 104/µL vs > 10 × 104/µL) was significantly associated with bleeding complications during the first day of admission (adjusted odds ratio [OR]: 1.865 [1.252-2.777], p = 0.002). CONCLUSIONS: In a large ECPR registry database in Japan, up to 22.1% of patients experienced bleeding complications requiring blood transfusion, IVR, or surgical intervention for hemostasis. The initial platelet count was a significant risk factor of early bleeding complications. It is necessary to lower the occurrence of bleeding complications from ECPR, and this study provided an additional standard value for future studies to improve its safety.

Colorectal Cancer Recurrence Prediction Using a Tissue-Free Epigenomic Minimal Residual Disease Assay.

PURPOSE: Post-treatment detection of circulating tumor DNA (ctDNA) is strongly predictive of recurrence. Most molecular residual disease (MRD) assays require prior tissue testing to guide ctDNA analysis, resulting in lengthy time to initial results and unevaluable patients. PATIENTS AND METHODS: We assessed a tissue-free assay (Guardant Reveal) that bioinformatically evaluates >20,000 epigenomic regions for ctDNA detection in 1,977 longitudinally collected post-operative plasma samples from 342 patients with resected colorectal cancer (CRC). RESULTS: We observed sensitive and specific detection of MRD associated with clinically meaningful differences in recurrence-free interval at each timepoint evaluated with a median lead time of 5.3 months. Longitudinal sensitivity in stage II or higher colon cancer was 81%. Sensitivity increased with serial measurement and varied by recurrence site: higher for liver (100%) versus lung (53%) and peritoneal (40%). Sensitivity among rectal cancer patients was 60% owing to a high proportion of lung metastases. Specificity was 98.2% among 1,461 post-treatment samples (99.1% among those with follow-up longer than the upper interquartile range of the lead time observed in this study). CONCLUSIONS: Our data demonstrate the potential clinical utility of ctDNA as a tool to improve management of stage II and higher CRC with a methodology that is non-invasive, accessible, and allows for rapid evaluation to inform clinical decisions.

Trial Protocol of a Phase II Study of mFOLFOXIRI after Metastasectomy in Patients with Oligometastatic Colorectal Cancer (FANTASTIC Study).

Background: The survival benefit of adjuvant chemotherapy after surgical resection of oligometastases from colorectal cancer (CRC) remains unclear. The prognostic role of circulating-tumor DNA (ctDNA) was reported recently and a risk stratification strategy based on monitoring minimal/molecular residual disease (MRD) has been proposed, however, which drug regimen is most effective for ctDNA-positive patients is unknown. Methods/Design: Oligometastatic CRC patients planning to undergo surgery were registered in this study. After metastasectomy, the registered patients were enrolled in the treatment arm, in which 8 courses of modified-FOLFOXIRI (mFOLFOXIRI; irinotecan 150 mg/m2, oxaliplatin 85 mg/m2, l-leucovorin (l-LV) 200 mg/m2, and 46-h continuous infusion of 5-fluorouracil (5-FU) 2400 mg/m2 every 2 weeks) followed by 4 courses of 5-FU/l-LV are administered. The patients who did not meet the eligibility criteria for the treatment arm or did not consent to mFOLFOXIRI enrolled in the observation arm in which standard of care treatment is provided. Prospective blood collections for retrospective ctDNA analysis are scheduled pre-surgery, and at 28 days, 4 and 7 months after surgery. The primary endpoint is treatment compliance at 8 courses of mFOLFOXIRI and the key secondary endpoints are the ctDNA-positivity rate and survival outcomes in ctDNA-positive and -negative groups. A total of 85 patients will be enrolled from 11 institutions. First patient-in was on July 2020. Accrual completed in February 2024. Discussion: This study will potentially identify a better treatment strategy for patients with resectable oligometastatic CRC having postsurgical ctDNA positivity, compared to the current standard of care approaches.

Clinical features associated with NeoRAS wild-type metastatic colorectal cancer A SCRUM-Japan GOZILA substudy.

"NeoRAS WT" refers to the loss of RAS mutations (MTs) following first-line treatment in metastatic colorectal cancer (mCRC). We evaluate the incidence and clinicopathological characteristics of NeoRAS WT mCRC using next-generation sequencing of plasma circulating tumor DNA. Patients with mCRC enrolled in the GOZILA study initially diagnosed with tissue RAS MT mCRC and received subsequent systemic therapy are eligible. NeoRAS WT is defined as the absence of detectable RAS MT in plasma and assessed in all eligible patients (Group A) and in a subgroup with at least one somatic alteration detected in plasma (Group B). Overall, 478 patients are included. NeoRAS WT prevalence is 19.0% (91/478) in Group A and 9.8% (42/429) in Group B. Absence of liver or lymph node metastasis and tissue RAS MTs other than KRAS exon 2 MTs are significantly associated with NeoRAS WT emergence. Overall, 1/6 and 2/6 patients with NeoRAS WT treated with anti-EGFR monoclonal antibodies (mAbs) show partial response and stable disease for ≥6 months, respectively. NeoRAS WT mCRC is observed at a meaningful prevalence, and anti-EGFR mAb-based therapy may be effective.

Plasma Angiogenic Factors as Predictors of the Efficacy of Second-line Chemotherapy Combined with Angiogenesis Inhibitors in Metastatic Colorectal Cancer: Results From the GI-SCREEN CRC-Ukit Study.

BACKGROUND: The significance of angiogenic factors as predictors of second-line (2L) chemotherapy efficacy when combined with angiogenesis inhibitors for metastatic colorectal cancer (mCRC) remains unestablished. PATIENTS AND METHODS: In this multicenter prospective observational study, 17 angiogenic factors were analyzed in plasma samples collected at pretreatment and progression stages using a Luminex multiplex assay. Patients who received chemotherapy plus bevacizumab (BEV group), FOLFIRI plus ramucirumab (RAM group), or FOLFIRI plus aflibercept (AFL group) as the 2L treatment were included. Interactions between pretreatment and treatment groups for progression-free survival (PFS), overall survival (OS), and response rate (RR) were assessed using the propensity-score weighted Cox proportional hazards model. RESULTS: From February 2018 to September 2020, 283 patients were analyzed in the 2L cohort. A strong interaction was observed for PFS between BEV and RAM with HGF, sNeuropilin-1, sVEGFR-1, and sVEGFR-3. Interactions for RR between the BEV and RAM groups were observed for sNeuropilin-1 and sVEGFR-1. Contrarily, OS, PlGF, sVEGFR-1, and sVEGFR-3 differentiated the treatment effect between BEV and AFL. Plasma samples were evaluable for dynamic analysis in 203 patients. At progression, VEGF-A levels significantly decreased in the BEV group and increased in the RAM and AFL groups. CONCLUSION: The pretreatment plasma sVEGFR-1 and sVEGFR-3 levels could be predictive biomarkers for distinguishing BEV and RAM when combined with chemotherapy in 2L mCRC treatment. Based on the VEGF-A dynamics at progression, selecting RAM or AFL for patients with significantly elevated VEGF-A levels may be a 2L treatment strategy, with BEV considered for the third-line treatment. CLINICAL TRIAL NUMBER: UMIN000028616.