Defective Biphenylene as High-Efficiency Hydrogen Evolution Catalysts.

Electrocatalysts play a pivotal role in advancing the application of water splitting for hydrogen production. This research unveils the potential of defective biphenylenes as high-efficiency catalysts for the hydrogen evolution reaction. Using first-principles simulations, we systematically investigated the structure, stability, and catalytic performance of defective biphenylenes. Our findings unveil that defect engineering significantly enhances the electrocatalytic activity for hydrogen evolution. Specifically, biphenylene with a double-vacancy defect exhibits an outstanding Gibbs free energy of -0.08 eV, surpassing that of Pt, accompanied by a remarkable exchange current density of -3.08 A cm-2, also surpassing that of Pt. Furthermore, we find the preference for the Volmer-Heyrovsky mechanism in the hydrogen evolution reaction, with a low energy barrier of 0.80 eV. This research provides a promising avenue for developing novel metal-free electrocatalysts for water splitting with earth-abundant carbon elements, making a significant step toward sustainable hydrogen production.

Corrigendum: Self-assembling and pH-Responsive protein nanoparticle as potential platform for targeted tumor therapy.

[This corrects the article DOI: 10.3389/fmolb.2023.1172100.].

Densification of SiCp/Al-Fe-V-Si Composites by the Wedge Rolling Method.

The densification of a SiCp/Al-Fe-V-Si billet was achieved by reducing the pores and oxide film between the particles by rolling. The wedge pressing method was used to improve the formability of the composite after jet deposition. The key parameters, mechanisms, and laws of wedge compaction were studied. The results showed that the pass rate was reduced by 10 to 15 percent when using steel molds during the wedge pressing process if the distance between the two ends of the billet was about 10 mm, which was beneficial to improve the compactness and formability of the billet. The density and stress of the surface of the material were higher than those of the interior, where the distribution of density and stress tended to be uniform as the overall volume of the material shrank. During the wedge extrusion process, the material in the preforming area was thinned along the thickness direction, while the material in the main deformation area was lengthened along the length direction. Under plane strain conditions, the wedge formation of spray-deposited composites follows the plastic deformation mechanism of porous metals. The true relative density of the sheet was higher than the calculated value during the initial stamping phase, but was lower than the calculated value when the true strain exceeded 0.55. This was due to the accumulation and fragmentation of SiC particles, which made the pores difficult to remove.

Self-assembling and pH-responsive protein nanoparticle as potential platform for targeted tumor therapy.

Frequent injections at high concentrations are often required for many therapeutic proteins due to their short in vivo half-life, which usually leads to unsatisfactory therapeutic outcomes, adverse side effects, high cost, and poor patient compliance. Herein we report a supramolecular strategy, self-assembling and pH regulated fusion protein to extend the in vivo half-life and tumor targeting ability of a therapeutically important protein trichosanthin (TCS). TCS was genetically fused to the N-terminus of a self-assembling protein, Sup35p prion domain (Sup35), to form a fusion protein of TCS-Sup35 that self-assembled into uniform spherical TCS-Sup35 nanoparticles (TCS-Sup35 NP) rather than classic nanofibrils. Importantly, due to the pH response ability, TCS-Sup35 NP well retained the bioactivity of TCS and possessed a 21.5-fold longer in vivo half-life than native TCS in a mouse model. As a result, in a tumor-bearing mouse model, TCS-Sup35 NP exhibited significantly improved tumor accumulation and antitumor activity without detectable systemic toxicity as compared with native TCS. These findings suggest that self-assembling and pH responding protein fusion may provide a new, simple, general, and effective solution to remarkably improve the pharmacological performance of therapeutic proteins with short circulation half-lives.

Ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry-based plasma metabolomics study of hepatoprotective effect of cuscutae semen on CCl4 -induced liver injury model of rats.

Hepatic disorders are a serious health problem threatening human beings. Cuscutae semen (CS), a widely used Chinese medicine, is a tonic to nourish the liver and kidney. Our research aimed to assess the hepatoprotective effect of CS on CCl4 -induced liver injury rats using plasma metabolomics. Liver injury in rats was induced by 40% CCl4 in olive oil twice a week for 21 days. The CS group received 2 g/kg of CS every day for 21 days. The liver tissues were used for histological studies. The serum was used for the analysis of biochemical parameters. Plasma metabolomic analysis was performed using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. CS could relieve hepatocyte necrosis and decrease the levels of serum biochemical parameters in comparison the with CCl4 group. Principal component analysis and orthogonal partial least squares-discriminant analysis on plasma metabolomes showed an obvious separation among the control, model, and CS groups. Heatmap showed that CS-administered mice had similar metabolite profiles as the control group. Seven influential pathways in plasma of the hepatoprotective effect impacted by CS were identified. This study confirmed the hepatoprotective effect of CS, and the related metabolic pathways were discussed.

Efficacy and Safety of Epirubicin Combined with Temozolomide for Treatment of Advanced Leiomyosarcoma.

BACKGROUND: Leiomyosarcoma (LMS) accounts for 24% of all soft tissue sarcomas (STSs) and this STS subtype has high metastatic potential. Previous studies indicated the best median progression-free survival (mPFS) time was 9.2 months and the best overall response rate (ORR) was 30.9%. We evaluated the efficacy and safety of epirubicin combined with temozolomide (EPI-TMZ) for treatment of advanced LMS. METHODS: This was a retrospective review of the records of patients with advanced LMS at the National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College. All patients initiated EPI-TMZ treatment between January 2018 and December 2020. RESULTS: We examined 15 patients who received EPI-TMZ for LMS. This was a first-line treatment in 6 patients, a second- or third-line treatment in 7 patients, and a fourth-line treatment in 2 patients. At the time of data cutoff (April 25, 2021), the median PFS was 10 months, 1 patient had clinical complete response (cCR), 7 had partial response (PR), and 7 had stable disease (SD). The overall response rate (ORR) was 53.3% (8/15) and the disease control rate (DCR) was 100.0% (15/15). The most common treatment-related adverse effects were leukopenia, neutropenia, thrombocytopenia, anemia, nausea, vomiting, fatigue, and oral mucositis. One patient had severe adverse effect (febrile neutropenia), but there were no treatment-related deaths. CONCLUSION: EPI-TMZ is potentially effective for treatment of advanced LMS, and the adverse effects appear tolerable. EPI-TMZ provided better outcomes than reported in previous studies of other treatments for advanced LMS.

The Cytochrome P450 Catalyzing C-S Bond Formation in S-Heterocyclization of Chuangxinmycin Biosynthesis.

Microbial sulfur-containing secondary metabolites show various biological activities, but the C-S bond-forming in their biosynthetic metabolism has not been thoroughly understood. Here, we present genetic, biochemical and structural characterization of a cytochrome P450 monooxygenase CxnD exhibiting C-S bond forming activity in S-heterocyclization of chuangxinmycin biosynthesis. In vivo and in vitro analyses demonstrated that CxnD generated an indole-fused dihydrothiopyran skeleton from a L-Trp-derived thiol intermediate. Furthermore, X-ray crystal structure of CxnD in complex with a substrate analogue and structure-based mutagenesis revealed intimate details of the substrate binding mode. A radical mechanism initiated by abstraction of the imino hydrogen atom or an electron from indole group of the substrate was proposed for CxnD, which provided valuable insights into the molecular basis for the intra-molecular C(sp2 )-H thiolation by the P450 in chuangxinmycin biosynthesis.

Tracking longitudinal genetic changes of circulating tumor DNA (ctDNA) in advanced Lung adenocarcinoma treated with chemotherapy.

INTRODUCTION: Pemetrexed combined with platinum complexes can be used as first-line treatment for advanced non-squamous non-small cell lung cancer (NSCLC), however, the efficacy and safety is varying from individuals. There is a need to better understand the genetic variations associated with platinum response. MATERIALS AND METHODS: We performed next-generation sequencing (NGS) based on BGI Oseq-ctDNA panel to analyze 98 longitudinal plasma samples from 32 lung adenocarcinoma patients during platinum-based chemotherapy, and a bioinformatic pipeline was developed to detect point mutations. RESULTS: We found that mutation burden was decreased after chemotherapy, which reflected chemotherapy sensitivity, especially the frequency of C>G and C>A substitutions. Moreover, neoplastic cells carrying a specific set of somatic mutations, such as EGFR(L858R), KRAS (p.G12C) were obviously correlated with platinum treatment. In addition, the MAPK pathway was found to have a pivotal role in NSCLC and platinum based response. Finally, we found that smokers benefit less from platinum-based chemotherapy. CONCLUSIONS: Collectively, this work described the dynamic changes of ctDNA mutation status during platinum-based treatment, which may contribute to advanced lung adenocarcinoma patients stratification and precision treatment.

Efficacy and safety of rh-endostatin (Endostar) combined with pemetrexed/cisplatin followed by rh-endostatin plus pemetrexed maintenance in non-small cell lung cancer: A retrospective comparison with standard chemotherapy.

BACKGROUND: Recombinant human endostatin (rh-endostatin) plus standard chemotherapy in advanced non-small cell lung cancer (NSCLC) patients has shown improved efficacy; however, it is unclear whether it is effective and safe when added to pemetrexed/cisplatin and used as maintenance therapy. METHODS: We retrospectively evaluated the data of untreated NSCLC patients administered rh-endostatin plus pemetrexed/cisplatin or pemetrexed/cisplatin. The primary endpoint was progression-free survival (PFS). RESULTS: Fifty-six and 39 patients received rh-endostatin plus pemetrexed/cisplatin and pemetrexed/cisplatin, and 34 and 29 underwent maintenance treatment, respectively. The median PFS was 10 months (95% confidence interval [CI] 5.85-14.15) in the rh-endostatin and 8.2 months (4.04-12.36) in the chemotherapy group, but the difference was not statistically significant (P = 0.13). In patients administered maintenance treatment, rh-endostatin plus pemetrexed was associated with prolonged PFS compared to single-agent pemetrexed when PFS was calculated from first dosing (13.7 [9.41-17.99] vs. 8.2 [4.16-12.24]; P = 0.032); however, PFS did not differ between the groups (hazard ratio 0.618; 95% CI 0.368-1.038; P = 0.069) after adjusting for clinical factors. No difference was observed in the objective response rate between the groups (48.2% vs. 38.5%; P = 0.346), with the exception of men (62.1% vs. 33.3%; P = 0.032) or in the incidence of drug-related or grade 3-4 adverse events. CONCLUSION: In previously untreated, advanced-stage NSCLC patients, first-line treatment with pemetrexed/cisplatin plus rh-endostatin did not prolong PFS or overall survival when compared to pemetrexed/cisplatin, but a trend of improved PFS was observed in patients administered maintenance rh-endostatin plus pemetrexed.

Biosynthesis of antibiotic chuangxinmycin from Actinoplanes tsinanensis.

Chuangxinmycin is an antibiotic isolated from Actinoplanes tsinanensis CPCC 200056 in the 1970s with a novel indole-dihydrothiopyran heterocyclic skeleton. Chuangxinmycin showed in vitro antibacterial activity and in vivo efficacy in mouse infection models as well as preliminary clinical trials. But the biosynthetic pathway of chuangxinmycin has been obscure since its discovery. Herein, we report the identification of a stretch of DNA from the genome of A. tsinanensis CPCC 200056 that encodes genes for biosynthesis of chuangxinmycin by bioinformatics analysis. The designated cxn cluster was then confirmed to be responsible for chuangxinmycin biosynthesis by direct cloning and heterologous expressing in Streptomyces coelicolor M1146. The cytochrome P450 CxnD was verified to be involved in the dihydrothiopyran ring closure reaction by the identification of seco-chuangxinmycin in S. coelicolor M1146 harboring the cxn gene cluster with an inactivated cxnD. Based on these results, a plausible biosynthetic pathway for chuangxinmycin biosynthesis was proposed, by hijacking the primary sulfur transfer system for sulfur incorporation. The identification of the biosynthetic gene cluster of chuangxinmycin paves the way for elucidating the detail biochemical machinery for chuangxinmycin biosynthesis, and provides the basis for the generation of novel chuangxinmycin derivatives by means of combinatorial biosynthesis and synthetic biology.

[Identification of 3-demethylchuangxinmycin from Actinoplanes tsinanensis CPCC 200056].

Chuangxinmycin (CM) from Actinoplanes tsinanensis was an antibiotic discovered by Chinese scientists about 40 years ago. It contains a new heterocyclic system of indole fused with dihydrothiopyran, whose biosynthetic mechanism remains unclear. CM is used as an oral medicine in the treatment of bacterial infections in China. The simple structure makes CM as an attractive candidate of structure modification for improvement of antibacterial activity. Recently, we analyzed the secondary metabolites of Actinoplanes tsinanensis CPCC 200056, a CM producing strain, as a natural CM analogue. We discovered the first natural CM analogue 3-demethylchuangxinmycin (DCM) as a new natural product. Compared to CM, DCM exhibited a much weaker activity in the inhibition of the bacterial strains tested. The finding provides valuable information for the structure-activity relationship in the biosynthesis of CM.

6-Deoxy-13-hydroxy-8,11-dione-dihydrogranaticin B, an intermediate in granaticin biosynthesis, from Streptomyces sp. CPCC 200532.

A new granaticin analogue and its hydrolysis product were isolated from Streptomyces sp. CPCC 200532. Their structures were determined to be 6-deoxy-13-hydroxy-8,11-dione-dihydrogranaticins B (1) and A (2), respectively, by detailed analysis of spectroscopic data. Compound 1 was regarded as an intermediate in granaticin biosynthesis, as it was bioconvertable to granaticin B. Compared to granaticin B, 1 showed similar cytotoxicity against cancer cell line HCT116, but decreased cytotoxicity against cancer cell lines A549, HeLa, and HepG2. Compound 2 displayed lower cytotoxicity than 1 against all four cancer cell lines tested.