Liver cancer is one of the most common malignant tumors worldwide. Currently, the available treatment methods cannot fully control its recurrence and mortality rate. Establishing appropriate animal models for liver cancer is crucial for developing new treatment technologies and strategies. The patient-derived xenograft (PDX) model preserves the tumor's microenvironment and heterogeneity, which makes it advantageous for biological research, drug evaluation, personalized medicine, and other purposes. This article reviews the development, preparation techniques, application fields, and challenges of PDX models in liver cancer, providing insights for the research and exploration of PDX models in diagnostic and therapeutic strategies of liver cancer.
Liver Neoplasms/drug therapy* ; Animals ; Humans ; Xenograft Model Antitumor Assays/methods* ; Mice ; Disease Models, Animal

Ulcerative colitis (UC) is a chronic inflammatory disorder with a complex etiology, characterized by intestinal inflammation and barrier dysfunction. Platycodon grandiflorus polysaccharides (PGP), the primary component of Platycodon grandiflorus, and hesperidin (Hesp), a prominent active component in Citrus aurantium L. (CAL), have both demonstrated anti-inflammatory properties. This study aims to elucidate the underlying mechanism of the synergistic effect of PGP combined with Hesp on UC, focusing on the coordinated interaction between the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathways. A mouse model of UC induced by dextran sulfate sodium (DSS) and a cell model using lipopolysaccharide (LPS)-induced RAW264.7/IEC6 cells were employed to investigate the in vitro and in vivo anti-inflammatory effects of PGP combined with Hesp on UC and its potential mechanism of action. The results indicated that compared to the effects of either drug alone, the combination of PGP and Hesp significantly modulated inflammatory factor levels, inhibited oxidative stress, regulated colonic mucosal immunity, suppressed apoptosis, and restored intestinal barrier function in vitro and in vivo. Further in vitro studies revealed that PGP significantly inhibited the PI3K/AKT signaling pathway, while Hesp significantly inhibited the JAK2/STAT3 signaling pathway. The use of inhibitors and activators targeting both pathways validated the synergistic effects of PGP combined with Hesp on the PI3K/AKT and JAK2/STAT3 signaling pathways. These findings suggest that PGP combined with Hesp exhibits a synergistic effect on DSS-induced colitis, potentially mediated through the phosphatase and tensin homolog (PTEN)/PI3K/AKT and interleukin-6 (IL-6)/JAK2/STAT3 signaling pathways.
Animals ; STAT3 Transcription Factor/genetics* ; Janus Kinase 2/genetics* ; Polysaccharides/administration & dosage* ; Colitis, Ulcerative/chemically induced* ; Mice ; Signal Transduction/drug effects* ; Proto-Oncogene Proteins c-akt/genetics* ; Drug Synergism ; Male ; Hesperidin/administration & dosage* ; Platycodon/chemistry* ; Phosphatidylinositol 3-Kinases/genetics* ; Disease Models, Animal ; RAW 264.7 Cells ; Mice, Inbred C57BL

L-citrulline is a nonprotein amino acid that plays an important role in human health and has great market demand. Although microbial cell factories have been widely used for biosynthesis, there are still challenges such as genetic instability and low efficiency in the biosynthesis of L-citrulline. In this study, an efficient, plasmid-free, non-inducible L-citrulline-producing strain of Escherichia coli BL21(DE3) was engineered by combined strategies. Firstly, a chassis strain capable of synthesizing L-citrulline was constructed by block of L-citrulline degradation and removal of feedback inhibition, with the L-citrulline titer of 0.43 g/L. Secondly, a push-pull-restrain strategy was employed to enhance the L-citrulline biosynthesis, which realized the L-citrulline titer of 6.0 g/L. Thirdly, the NADPH synthesis and L-citrulline transport were strengthened to promote the synthesis efficiency, which achieved the L-citrulline titer of 11.6 g/L. Finally, fed-batch fermentation was performed with the engineered strain in a 3 L fermenter, in which the L-citrulline titer reached 44.9 g/L. This study lays the foundation for the industrial production of L-citrulline and provides insights for the modification of other amino acid metabolic networks.
Citrulline/biosynthesis* ; Escherichia coli/genetics* ; Metabolic Engineering/methods* ; Fermentation ; NADP/biosynthesis*

BACKGROUND:Dapagliflozin,an inhibitor of sodium-glucose cotransporter 2,can delay the progression of atherosclerosis by regulating glucose metabolism,inhibiting inflammation and improving endothelial cell function. OBJECTIVE:To study the effect of dapagliflozin on cell pyroptosis and endothelial dysfunction induced by oxidized low-density lipoprotein. METHODS:Human umbilical vein endothelial cells were divided into a control group(no intervention),a model group(treated with oxidized low-density lipoprotein for 24 hours),and a dapagliflozin group(treated with oxidized low-density lipoprotein + dapagliflozin for 24 hours).Endothelial cell proliferation activity was measured by cell counting kit-8 assay.The levels of intercellular adhesion molecule 1,vascular cell adhesion molecule 1,and monocyte chemotactic protein-1 in cell supernatant were detected using ELISA.Nitric oxide level in the cells was detected by nitrate reductase assay.The pyroptosis rate and characteristics of endothelial cells were detected by Hoechst 33342/PI fluorescence co-staining and lactate dehydrogenase release assay.The protein expression levels of NLRP3,caspase-1,GSDMD,interleukin-1β,and interleukin-18 were detected by western blot assay. RESULTS AND CONCLUSION:(1)Oxidized low-density lipoprotein could cause pyroptosis and dysfunction of endothelial cells.(2)Compared with the control group,the level of nitric oxide and cell activity were decreased(P<0.05),while lactate dehydrogenase,intercellular adhesion molecule 1,vascular cell adhesion molecule 1,and monocyte chemotactic protein-1 levels were significantly increased in the model group(P<0.05).Compared with the model group,cell activity and nitric oxide levels significantly increased(P<0.05),but lactate dehydrogenase,intercellular adhesion molecule 1,vascular cell adhesion molecule 1,and monocyte chemotactic protein-1 levels were significantly diminished in the dapagliflozin group(P<0.05).(3)Compared with the model group,cell pyroptosis rate and the protein expression of pyroptosis factor NLRP3,caspase-1,GSDMD,interleukin-18 and interleukin-1β significantly reduced in the dapagliflozin group(P<0.05).(4)The results indicate that dapagliflozin inhibits oxidized low-density lipoprotein-induced endothelial pyroptosis and ameliorates endothelial cell dysfunction.

Objective To construct a recombinant eukaryotic expression vector of human tumor suppressor p53-binding protein 2(TP53BP2)and transfect human embryonic kidney Expi293F cells.High-purity recombinant human full-length TP53BP2 protein was obtained and its biological activity was identified.Methods The TP53BP2 gene sequence was queried on the UniProt website,and the Expi293F expression system was optimized.The TP53BP2 gene was connected to pcDNA3.1(+)-P2A-eGFP vector by homologous recombination,and identified by double enzyme digestion and sequencing.Transect pcDNA3.1(+)-P2A-eGFP-TP53BP2 plasmid into Expi293F cells of Polyethylenimine(PEI),observe the transfection efficiency with a fluorescence microscope,collected cells from the experiment group and control group.The expression level of TP53BP2 recombinant protein was detected by Western blot(WB).Protein was purified by His label purification kit and Superdex 20010/300 GL chromatographic column.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis.The purified recombinant protein was identified by SDS-PAGE.Combining recombinant human full-length TP53BP2 protein with p65 protein was investigated for Co-immunoprecipitation(Co-IP)precipitation.Recombinant human full-length TP53BP2 protein was co-localized with p65 protein by Immunofluorescence(IF).The surface plasmon resonance(SPR)technique was used to detect the interaction between purified recombinant human full-length TP53BP2 protein and TP53BP2 antibody.Results The recombinant plasmid pcDNA3.1(+)-P2A-eGFP-TP53BP2 was successfully constructed by sequencing and double digestion.The fluorescence microscopy results showed that the transfection efficiency was about 60%.WB showed that the TP53BP2 protein was overexpressed in Expi293F cells,which proved that transfection was successful.SDS-PAGE results showed that the purity of the purified recombinant protein was above 90%,which proved that the purification was successful.Co-IP results showed that the TP53BP2 could interact with p65 protein.The results of IF showed that His tag protein,TP53BP2 protein,and p65 protein were co-located,indicating the interaction between the three proteins.SPR results showed that the purified TP53BP2 recombinant protein had good binding activity with the TP53BP2 antibody.These results all prove that the recombinant human full-length TP53BP2 protein has biological activity.Conclusion The eukaryotic expression vector of TP53BP2 gene was successfully constructed and the recombinant full-length human TP53BP2 protein with biological activity was successfully expressed in human embryonic kidney Expi293F cells.It lays a foundation for further study on the structure and function of TP53BP2.

To screen and identify the key host proteins interacting with the non-structural protein 15 (Nsp15) of porcine epidemic diarrhea virus (PEDV). The IP/pull-down assay and mass spectrometry were employed to screen and identify the host proteins interacting with Nsp15. The interaction between the host protein and Nsp15 was studied by co-immunoprecipitation and laser scanning confocal microscopy. Finally, Western blotting and RT-qPCR were employed to examine the interaction between SLC25a3 and PEDV. The recombinant eukaryotic expression vector pcDNA3.1(+)-Flag-Nsp15 was successfully constructed, and the host protein SLC25a3 interacting with PEDV Nsp15 was screened out. An interaction existed between SLC25a3 and Nsp15, and SLC25a3 significantly inhibited PEDV replication in a dose-dependent manner. SLC25a3 inhibits PEDV replication. The results of this study provide a basis for deciphering the role and mechanism of SLC25a3 in the host immune response to PEDV infection.
Porcine epidemic diarrhea virus/genetics* ; Viral Nonstructural Proteins/metabolism* ; Animals ; Swine ; Virus Replication ; Coronavirus Infections/veterinary* ; Swine Diseases/metabolism*

Objective : To investigate the role of dapagliflozin ( DAPA) in ox⁃LDL⁃induced pyroptosis of human myeloid leukemia monocytes (THP⁃1) derived foam cells . Methods : THP⁃1 ⁃derived foam cell pyroptosis model was constructed by ox⁃LDL⁃induced THP⁃1derived macrophages . The experimental groups were set as follows : the blank control group(NC) , the ox⁃LDL group(ox⁃LDL) , and the drug intervention group(ox⁃LDL + DAPA) . Oil Red Ostaining was used to detect the foam cell levels of macrophages . The cell proliferation and toxicity assay kit was used to detect the effect of DAPA on foam cell viability . Hoechst 33342/propidium iodide(PI) double staining was used to detect THP⁃1 derived foam cell pyroptosis . Cell immunofluorescence double staining was used to detect the effect of DAPA on the expression of pyroptosis key factor Caspase⁃1 in foam cells . The activity of lactate dehydrogenase (LDH) in the cell culture medium was detected using a microplate enzyme⁃linked immunosorbent assay. qRT⁃PCR and Western blot were used to detect the mRNA and protein expression levels of Nod⁃like receptor pyrindomain containing 3 (NLRP3) , cystein⁃containing aspartate⁃specific protease⁃1( Caspase⁃1 ) , apoptosis⁃associated⁃speck⁃like protein containing CARD(ASC) ,gasdermin⁃D (GSDMD) , interleukin(IL) Ⅳ18 and IL⁃1β , respectively . Results : The CCK⁃8 assay indicated that the optimal intervention concentration of DAPA was 10 μmol/L. Oil Red O staining confirmed the successful construction of the THP⁃1 ⁃derived foam cell pyroptosis model . Compared with the blank control group , the expression levels of NLRP3 , Caspase⁃1 , ASC , GSDMD , IL⁃18 , IL⁃1β mRNA and protein significantly increased in ox⁃LDL group(P < 0. 05) , as well as the number of PI⁃positive cells and LDH activity(P < 0. 05) , the fluorescence intensity of Caspase⁃1 and the number of redlipid droplets in the cytoplasm of the cells . However , these effects were significantly reversed after DAPA intervention in the ox⁃LDL + DAPA group(P < 0. 05) . Conclusion DAPA inhibits ox⁃LDL⁃induced pyroptosis in THP⁃1 ⁃derived foam cells .

Fermentative production of amino acids is one of the pillars of the fermentation industry in China. Recently, with the fast development of metabolic engineering and synthetic biology technologies, the metabolic engineering for production of amino acids has been flourishing. Conventional forward metabolic engineering, reversed metabolic engineering based on omics data and in silico simulation, and evolutionary metabolic engineering mimicking the natural evolution, have shown increasingly promising applications. A series of highly efficient and robust amino acids-producing strains have been developed and applied in the industrial production of amino acids. The increasingly fierce market competition has put forward new requirements for strain breeding and selection, such as developing high value-added amino acids, dynamic regulation of cellular metabolism, and adapting to the requirements of new process. This review summarizes the advances and prospects in metabolic engineering for the production of amino acids.
Amino Acids ; China ; Corynebacterium glutamicum/genetics* ; Metabolic Engineering ; Synthetic Biology

BACKGROUND: The 2019 novel coronavirus disease (COVID-19) has had a massive impact on public health, resulting in sudden dietary and behavioral habit changes. Frontline epidemic prevention workers play a pivotal role against COVID-19. They must face high-risk infection conditions, insufficient anti-epidemic material supplies, mental pressure, and so on. COVID-19 seriously affects their dietary and behavioral habits, and poor habits make them more susceptible to COVID-19. However, their baseline dietary and behavioral habits before COVID-19 and their willingness to change these habits after the outbreak of COVID-19 remain unclear for these workers in China. This study aimed to explore the baseline dietary and behavioral habits of frontline workers and their willingness to change these habits after the outbreak of the epidemic; in addition, susceptible subgroups were identified by stratified analyses as targets of protective measures to keep them from being infected with COVID-19. METHODS: A cross-sectional study was conducted through an online questionnaire using a sample of 22,459 valid individuals living in China, including 9402 frontline epidemic prevention workers. RESULTS: Before COVID-19, 23.9% of the frontline epidemic prevention workers reported a high-salt diet, 46.9% of them reported a high frequency of fried foods intake, and 50.9% of them smoked cigarettes. After the outbreak of COVID-19, 34.6% of them expressed a willingness to reduce salt intake, and 43.7% of them wanted to reduce the frequency of pickled vegetables intake. A total of 37.9% of them expressed a willingness to decrease or quit smoking, and 44.5% of them wanted to increase sleep duration. Significant differences in the baseline dietary and behavioral habits and the willingness to change their habits were observed between frontline epidemic prevention workers and other participants. Among the frontline epidemic prevention workers with poor dietary and behavioral habits before COVID-19, frontline epidemic prevention experience was a promoting factor for adopting worse dietary and behavioral habits, including those in the high-salt intake subgroup (OR, 2.824; 95% CI, 2.341-3.405) and the 11-20 cigarettes/day subgroup (OR, 2.067; 95% CI, 1.359-3.143). CONCLUSIONS The dietary and behavioral habits of frontline epidemic prevention workers were worse than that those of other participants before COVID-19. They had a greater willingness to adopt healthy dietary and behavioral habits after experiencing the outbreak of COVID-19. However, frontline epidemic prevention workers with poor dietary and behavioral habits before COVID-19 continued in engage in these poor habits. Dietary and behavioral intervention policies should be drafted to protect their health, especially frontline epidemic prevention workers with poor habits at baseline.
Adult ; COVID-19/psychology* ; China/epidemiology* ; Cross-Sectional Studies ; Diet/standards* ; Female ; Health Behavior ; Health Knowledge, Attitudes, Practice ; Health Personnel/psychology* ; Humans ; Male ; Risk Reduction Behavior ; SARS-CoV-2 ; Surveys and Questionnaires

Objective:To observe the relationship between the occurrence of symptomatic hypocalcemia (SH) and various potential influencing factors in patients after thyroidectomy, stratify according to the scope of thyroidectomy, and explore the predictive value of intact parathyroid hormone (iPTH) for postoperative SH.Methods:Among 3 379 patients with thyroidectomy who admitted into the First Affiliated Hospital of Zhengzhou University from January 2020 to February 2021, 122 patients with SH after thyroidectomy were collected retrospectively and set as SH group. 100 patients of the remaining 3 200 patients who did not suffer from SH in the same year were selected by systematic sampling method and set as control group. Pearson correlation analysis was used to analyze the potential influencing factors such as age, preoperative calcium, postoperative calcium, preoperative iPTH, postoperative iPTH, central lymph node number, blood loss, operation duration, gender, lymph node dissection method, thyroidectomy range, postoperative pathological type and other. Among them, the measurement data of normal distribution were expressed by mean±standard deviation( Mean± SD), t-test was used for the comparison between the two groups, and Chi-square test was used for count data. By drawing the receiver operating characteristic curve (ROC), the iPTH levels in patients with and without SH before/after operation (different surgical methods) were studied, and the diagnostic threshold, sensitivity and specificity of iPTH were predicted. Results:Among 3 379 patients, 122 patients suffered from SH after thyroidectomy, with the incidence rate of 3.6%. There were significant differences in gender (8 males and 114 females in SH group; 27 males and 73 females in control group), whether lateral area dissection was performed (58 cases with dissection and 64 cases without dissection in SH group; 7 cases with dissection and 93 cases without dissection in control group), thyroidectomy range (14 cases with one side and 108 cases with both sides in SH group; 73 cases with one side and 27 cases with both sides in control group), age (40.1 years old vs 43.2 years old), dissection number of central lymph nodes (8.6 vs 4.6), dissection number of cervical lymph nodes (12.3 vs 0.7), blood loss (22.8 mL vs 11.0 mL), operation duration (1.7 h vs 0.8 h), postoperative iPTH (16.4 pg/mL vs 41.9 pg/mL), preoperative iPTH (39.4 pg/mL vs 47.8 pg/mL) in SH group; and postoperative calcium level (1.9 mmol/L vs 2.2 mmol/L). There was significant differences between the two groups ( P<0.05). However, there was no significant differences between them with postoperative pathological type (4 cases with toxic goiter, 3 cases with medullary thyroid carcinoma, 1 case with thyroid follicular carcinoma, 114 cases with papillary thyroid carcinoma in SH group; 1 case with medullary thyroid carcinoma, 1 case of thyroid follicular carcinoma, 98 cases with papillary thyroid carcinoma in control group, P=0.25) and preoperative calcium (2.3 mmol/L vs 2.3 mmol/L, P=0.10). For patients with bilateral thyroidectomy, SH was easy to occur when postoperative iPTH < 20.08 pg/mL, and its sensitivity and specificity were 74.07% and 96.30%; however, for patients with unilateral thyroidectomy, SH was easy to occur when iPTH < 24.00 pg/mL after operation. Conclusions:Gender, age, postoperative calcium, preoperative iPTH, postoperative iPTH, central lymph node number, blood loss, operation duration, lymph node dissection method and thyroidectomy range are important factors affecting the occurrence of SH after thyroidectomy. With the expansion of surgical range, the postoperative iPTH level gradually decreases, which predicts the occurrence of symptomatic hypocalcemia. In order to avoid the occurrence of symptomatic hypocalcemia after operation, it is necessary to supplement calcium in time according to the range of operation and postoperative iPTH level.