Modulating Tankyrases (TNKS), interactions with USP25 to promote TNKS degradation, rather than inhibiting their enzymatic activities, is emerging as an alternative/specific approach to inhibit the Wnt/β-catenin pathway. Here, we identified UAT-B, a novel neoantimycin analog isolated from Streptomyces conglobatus, as a small-molecule inhibitor of TNKS-USP25 protein-protein interaction (PPI) to overcome multi-drug resistance in colorectal cancer (CRC). The disruption of TNKS-USP25 complex formation by UAT-B led to a significant decrease in TNKS levels, triggering cell apoptosis through modulation of the Wnt/β-catenin pathway. Importantly, UAT-B successfully inhibited the CRC cells growth that harbored high TNKS levels, as demonstrated in various in vitro and in vivo studies utilizing cell line-based and patient-derived xenografts, as well as APC^min/+ spontaneous CRC models. Collectively, these findings suggest that targeting the TNKS-USP25 PPI using a small-molecule inhibitor represents a compelling therapeutic strategy for CRC treatment, and UAT-B emerges as a promising candidate for further preclinical and clinical investigations.

Objective:We genetically modified our non-replicating vaccinia virus NTV to improve its immunogenicity.Methods:We constructed NTV-modified strain NTV-ΔF1L-C7L by homologous recombination of vaccinia virus based on CRISPR-Cas9 technology by inserting the C7L gene while deleting the F1L gene. The recombinant virus NTV-ΔF1L-C7L was then immunized with 10 7 PFU in BALB/c mice, and the levels of humoral and cellular immunity induced by NTV-ΔF1L-C7L were detected by ELISA and ELISpot method, respectively, and the levels of neutralizing antibodies were determined by the phage-reduced neutralization assay. Results:The PCR and western- blot identification proved that the F1L gene of the constructed NTV-modified strain NTV-ΔF1L-C7L was missing, while the C7L gene was inserted back in the region, and the C7L gene could be expressed normally, indicating that the recombinant virus was constructed correctly. After immunization of mice with NTV-ΔF1L-C7L, ELISA result showed that the recombinant virus NTV-ΔF1L-C7L induced a higher level of IgG antibody than NTV; ELISpot result also showed that the recombinant virus was able to induce a higher level of IFN-γ; and the result of plaque reduction neutralization test showed that the recombinant virus was able to induce a higher level of IFN-γ antibody than that of NTV.Conclusions:We correctly constructed the NTV gene-modified strain NTV-ΔF1L-C7L, which induced stronger humoral and cellular immunity compared with NTV, and provided reference data for the research and development of replacement products for smallpox or monkeypox vaccines.

Objective:To accurately ascertain the whole genome sequencing and the composition of open reading frames (ORFs) of non-replicating Tiantan strain of vaccinia virus (NTV) using next-generation long-read sequencing technology.Methods:NTV, obtained from our laboratory stock, was amplified and purified on chicken embryo fibroblast cells(CEFs), and the full-length genomic nucleic acid of NTV was extracted. The PacBio HiFi sequencing platform was utilized for de novo assembly to obtain the complete genomic sequence of NTV. Using a homology annotation strategy, we identified its ORF composition and compared it with known non-replicating vaccinia virus strains. Results:The total length of NTV′s genome was 171 729 bp, with a GC content of 33%. Its unique inverted terminal repeat (ITR) region comprised hairpin structures, two tandem repeat regions, and three non-repeat regions. NTV contained 166 ORFs, with major differences observed in the ITR and its surrounding regions when compared to MVA-BN and NYVAC. These three strains shared a common set of 138 ORFs. NTV encoded six unique ORFs related to virus evasion of host antiviral response.Conclusions:This study accurately determines the whole genome sequencing and ORFs composition of NTV, and reveals its similarities and differences with other replication-deficient vaccinia virus strains, which pave a way for the development and application of the next generation of monkeypox vaccines and novel viral vectors.

Objective:To develop a recombinase-aided amplification (RAA)-clustered regularly interspaced short palindromic repeats(CRISPR)/Cas12a-based nucleic acid assay for monkeypox virus with high specificity and sensitivity.Methods:RAA primers and CRISPR RNA (crRNA) were designed based on the known conserved regions of the monkeypox virus gene and synthesized, and specific crRNAs were screened using fluorescence detection. The sensitivity and specificity of the detection system were evaluated.Results:An RAA-CRISPR/Cas12a-based nucleic acid assay for monkeypox virus was developed with a sensitivity of 2.5 copies/reaction and high specificity without cross-reactivity with ectromelia virus and vaccinia virus.Conclusions:An RAA-CRISPR/Cas12a-based nucleic acid assay for monkeypox virus was established, which would provide a powerful tool for efficient, rapid and specific detection of monkeypox virus.

Objective:Through the study of the cell biological characteristics and virulence in mice in vivo of three non-replicating vaccinia virus modified strains to provide reference for the development of smallpox/monkeypox vaccine replacement products.Methods:Replicating vaccinia virus Tiantan strain VTT and non-replicating Tiantan Vaccinia Strain NTV were studied in BHK-21/CEF and its modified strains NTV-C7L, NTV-△F1L-C7L, NTV-K1L were amplified, purified, and identified by Western blotting. The virulence and diffusivity of each strain in cells were evaluated by immune-plaque assay. The replication dynamics curves were used to compare the replication differences between the strains, and the weight loss was observed by intranasal route in the mouse model to compare the virulence levels of the viruses.Results:In this study, Western blotting result proved that the amplified and purified vaccinia virus strains were correct. Immunophagocytosis and replication kinetics showed that the replication capacity of the three NTV modified strains in CEF was similar to that of NTV. The diffusion ability and replication ability between Vero cells were improved, but the replication multiple was less than 100 times. The replication level of MRC-5 was significantly enhanced compared with that of NTV, and the replication ratio of NTV-C7L was more than 20000 times. The virulence in mice showed that the body weight of the three NTV modified strains had no statistical significance compared with that of NTV.Conclusions:The three NTV modified strains recovered their replication ability in human MRC-5 cells, but their virulence in mice was similar to that of NTV, which provided the preliminary conditions for being candidate strains of smallpox/monkeypox vaccine replacement products.

SIRT6 belongs to the conserved NAD⁺-dependent deacetylase superfamily and mediates multiple biological and pathological processes. Targeting SIRT6 by allosteric modulators represents a novel direction for therapeutics, which can overcome the selectivity problem caused by the structural similarity of orthosteric sites among deacetylases. Here, developing a reversed allosteric strategy AlloReverse, we identified a cryptic allosteric site, Pocket Z, which was only induced by the bi-directional allosteric signal triggered upon orthosteric binding of NAD⁺. Based on Pocket Z, we discovered an SIRT6 allosteric inhibitor named JYQ-42. JYQ-42 selectively targets SIRT6 among other histone deacetylases and effectively inhibits SIRT6 deacetylation, with an IC₅₀ of 2.33 μmol/L. JYQ-42 significantly suppresses SIRT6-mediated cancer cell migration and pro-inflammatory cytokine production. JYQ-42, to our knowledge, is the most potent and selective allosteric SIRT6 inhibitor. This study provides a novel strategy for allosteric drug design and will help in the challenging development of therapeutic agents that can selectively bind SIRT6.

Objective:To study the cell morphological changes and related molecular mechanisms of non-replicating vaccinia virus NTV infection with human cells and to provide a scientific basis for the further optimization, transformation and application of NTV vectors.Methods:HeLa cells were infected with vaccinia virus Tiantan strain VTT and non-replicating vaccinia virus NTV, and the morphological changes of cells were observed. Then cells were harvested, and rRNA break levels were detected by electrophoresis and the molecular signals associated with apoptosis were detected by Western blotting, and the pathways and mechanisms of NTV-induced early apoptosis were preliminarily determined.Results:In this study, in terms of cell morphology, it was observed that cells infected with NTV were able to have cell rounding, wrinkles and other lesions at an earlier time compared with VTT. DAPI staining showed that NTV-infected nuclei exhibited high chromatin aggregation, marginalization, and disintegration over time. The rRNA fracture level test result indicate that rRNA has been broken and degraded after 16 hours of NTV infection. The Western blotting test result showed that the molecular signals of PARP, caspase-3 and caspase-9 that were stronger than in normal cells could be detected in NTV-infected HeLa cells, but there was no significant increase in caspase-8, while the result of VTT were the opposite of those in NTV.Conclusions:NTV can induce apoptosis in the early stage and provide a theoretical basis for the modification of vaccinia vectors.

Objective:Using clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated protein 9 (Cas9) technology to edit Vaccinia virus (VACV) thymidine kinase (TK) Region for targeted recombination to establish an efficient vaccinia virus insertion recombination technology.Methods:We designed and synthesized guide RNAs(gRNA)targeting the TK region and then cloned individual gRNA into the PX458 vector that removes nuclear localization signals, and modified the original TK region recombinant plasmid. The gRNA and Cas9 co-expression plasmids were transfected into 293T cells separately to mediate the homologous recombination of vaccinia virus (VACV) and TK region recombination plasmid, and then the rate of viral recombination was evaluated by the appearance of blue and white spots.Results:The recombination efficiency mediated by the gRNA sequence designed and synthesized in this study is more than 1%, which is more than 10 times higher than the classical homologous recombination method .Conclusions:This study used CRISPR/Cas9 technology to establish a highly efficient recombinant vaccinia virus system, which provides technical support for pre-clinical research in vaccines or multivalent research of emerging infectious diseases, as well as tumor treatment.

Objective To discover the medicinal active molecules from the fermentation extract of sponge-symbiotic Streptomyces sp. LHW2432. Methods Compounds were isolated and purified from the fermentation extract of LHW2432 by silica gel, ODS chromatographic columns, and HPLC. The structures of the compounds were elucidated based on the analyses of modern spectrum technologies and the related literatures research. Through plate coating method and broth microdilution method, the antimicrobial activities were tested by the indicator strains of Bacillus mycoides, methicillin-resistant Staphylococcus aureus (MRSA), Mycobacterium smegmatis, Candida Albicans, and Escherichia coli. Results Five compounds were discovered and their structures were identified as descycloavandulyl-lavanduquinocin (1), N-acetyltyramine (2), phomapyrone C (3), germicidin A (4), and germicidin I (5). Compound 1 showed inhibitory activities against MRSA (MIC, 100 μg/ml) and M. smegmatis (MIC, 64 μg/ml), respectively. Conclusion Five compounds were discovered from LHW2432, among which compound 1 was a new natural product and could be used as a precursor of the tricyclic carbazole alkaloids with neuroprotective activity. Moreover, compound 1 showed weak inhibitory activities against gram-positive pathogenic bacteria.

Objective:To investigate the effect of situational simulation combined with video feedback in cardiopulmonary and abdominal clinical probation of diagnostics.Methods:Two hundred and twenty-four clinical undergraduates from the second affiliated hospital of Guangxi Medical University were randomized into the experimental group ( n=112) and the control group ( n=112). The experimental group applied situational simulation combined with video feedback methods in the cardiopulmonary and abdominal clinical probation. In other words, according to the assignment of diseases, two students played the role of "physician and patient" and conducted corresponding consultation and physical examination, in which the positive and negative video feedback were integrated to standardize students' physical examination skills. The control group adopted conventional teaching method. The teaching effect of the two groups was evaluated through unified and standardized scores of theoretical tests, cases analysis, and clinical skills operation, and the experimental group was conducted anonymous questionnaires to 112 students. SPSS 22.0 was used to perform the t test. Results:The evaluation results show that the average scores of theoretical tests (90.12±0.94), cases analysis (9.30±0.10) and physical examination (93.50±0.72) in the experimental group are higher than those of the control group, (83.20±1.66), (8.10±0.11), (85.00±1.75), respectively, with statistical significance ( P<0.05). All 112 questionnaires were collected, with an effective rate of 100%. The percentage of "yes" respondents is as follows, 91.1% of "Enhancing the mastery and application of knowledge"; 97.3% of "Cultivating clinical thinking"; 87.5% of "Improving doctor-patient communication skills"; however, there are 93.8% students believe that this new teaching approach takes more time to prepare before class, consequently, their initiative and enthusiasm of study and learning interest have slid into decline, with percentage of 80.4% and 83.0%, respectively. Conclusion:The teaching method of situational simulation and video feedback in cardiopulmonary and abdominal clinical probation of diagnostics is beneficial to enhance students' understanding and mastery of theoretical knowledge, standardize physical examinations, cultivate clinical thinking ability and improve the doctor-patient communication skills. However, it takes a lot of time for students to prepare before class. If they fail to make reasonable arrangements, the teaching effect will be half the effort and students' initiative and enthusiasm of learning will be reduced.