Ionic Liquid-Mediated Dynamic Polymerization for Facile Aqueous-Phase Synthesis of Enzyme-Covalent Organic Framework Biocatalysts.

Utilizing covalent organic framework (COF) as a hypotoxic and porous scaffold to encapsulate enzyme (enzyme@COF) has inspired numerous interests at the intersection of chemistry, materials, and biological science. In this study, we report a convenient scheme for one-step, aqueous-phase synthesis of highly crystalline enzyme@COF biocatalysts. This facile approach relies on an ionic liquid (2 µL of imidazolium ionic liquid)-mediated dynamic polymerization mechanism, which can facilitate the in situ assembly of enzyme@COF under mild conditions. This green strategy is adaptive to synthesize different biocatalysts with highly crystalline COF "exoskeleton", as well evidenced by the low-dose cryo-EM and other characterizations. Attributing to the rigorous sieving effect of crystalline COF pore, the hosted lipase shows non-native selectivity for aliphatic acid hydrolysis. In addition, the highly crystalline linkage affords COF "exoskeleton" with higher photocatalytic activity for in situ production of H2 O2 , enabling us to construct a self-cascading photo-enzyme coupled reactor for pollutants degradation, with a 2.63-fold degradation rate as the poorly crystalline photo-enzyme reactor. This work showcases the great potentials of employing green and trace amounts of ionic liquid for one-step synthesis of crystalline enzyme@COF biocatalysts, and emphasizes the feasibility of diversifying enzyme functions by integrating the reticular chemistry of a COF.

Protocol for mechanochemistry-guided assembly strategy for enzyme encapsulation using covalent organic frameworks.

Enzyme immobilization into porous frameworks is an emerging strategy for enhancing the stability of dynamic conformation and prolonging the lifespan of enzymes. Here, we present a protocol for a de novo mechanochemistry-guided assembly strategy for enzyme encapsulation using covalent organic frameworks. We describe steps for mechanochemical synthesis, enzyme loading measurements, and material characterizations. We then detail evaluations of biocatalytic activity and recyclability. For complete details on the use and execution of this protocol, please refer to Gao et al. (2022).1.

Encapsulating and stabilizing enzymes using hydrogen-bonded organic frameworks.

Enzymes are outstanding natural catalysts with exquisite 3D structures, initiating countless life-sustaining biotransformations in living systems. The flexible structure of an enzyme, however, is highly susceptible to non-physiological environments, which greatly limits its large-scale industrial applications. Seeking suitable supports to immobilize fragile enzymes is one of the most efficient routes to ameliorate the stability problem. This protocol imparts a new bottom-up strategy for enzyme encapsulation using a hydrogen-bonded organic framework (HOF-101). In short, the surface residues of the enzyme can trigger the nucleation of HOF-101 around its surface through the hydrogen-bonded biointerface. As a result, a series of enzymes with different surface chemistries are able to be encapsulated within a highly crystalline HOF-101 scaffold, which has long-range ordered mesochannels. The details of experimental procedures are described in this protocol, which involve the encapsulating method, characterizations of materials and biocatalytic performance tests. Compared with other immobilization methods, this enzyme-triggering HOF-101 encapsulation is easy to operate and affords higher loading efficiency. The formed HOF-101 scaffold has an unambiguous structure and well-arranged mesochannels, favoring mass transfer and understanding of the biocatalytic process. It takes ~13.5 h for successful synthesis of enzyme-encapsulated HOF-101, 3-4 d for characterizations of materials and ~4 h for the biocatalytic performance tests. In addition, no specific expertise is necessary for the preparation of this biocomposite, although the high-resolution imaging requires a low-electron-dose microscope technology. This protocol can provide a useful methodology to efficiently encapsulate enzymes and design biocatalytic HOF materials.

Association between potentially functional polymorphisms of chemokine family members and the survival of esophageal cancer patients in a Chinese population.

Background: The chemokine family plays an important role in the growth, invasion, and metastasis of tumors. However, most studies have only focused on a few genes or a few gene loci, and thus could not reveal the associations between functional polymorphisms of chemokine family members and tumor progression. This study aimed to determine the associations between single nucleotide polymorphisms (SNPs) of chemokine family members and the prognosis of esophageal cancer (EC). Methods: The Cox risk proportional model and log-rank test were used to analyze the associations of 16 potentially functional SNPs in 13 genes from the chemokine family with the survival of 729 Chinese patients with EC. Results: Prognostic analysis on the 16 SNPs showed that different genotypes of 5 SNPs were associated with patients' survival and the risk of death. Multivariate Cox regression analysis showed that the risk of death was higher in CCL26rs2302009 genotype A/C carriers than in A/A carriers and it was also higher in CX3CL1rs2239352 genotype T/T carriers than in C/C carriers. Stepwise Cox regression analysis showed that CCL26rs2302009 genotype A/C was an independent prognostic factor of EC, and its association with increased risk of death was stronger in patients who were ≤60 years old, female, with tumors located in the middle part of esophagus, with undifferentiated or poorly differentiated tumors, with early-stage pathologic type disease, with the longest diameter of tumor ≤5cm than in their counterparts. Conclusion: These findings suggest that CCL26rs2302009 may be a candidate biomarker for EC and its effect on death risk are associated with the histological grade, pathologic type, and the longest diameter of tumor.

Gene expression profile analysis of ENO1 knockdown in gastric cancer cell line MGC-803.

Gastric cancer (GC) is the third leading cause of cancer-associated mortality. In a previous study, we identified that α-enolase (ENO1) promoted cell migration in GC, but the underlying molecular mechanisms remain to be fully elucidated. In the present study, small interfering RNAs were identified to interfere with ENO1 expression. The cDNA expression profiling was performed using an Affymetrix mRNA array platform to identify genes that may be associated with ENO1 in human GC cell line MGC-803. The differentially expressed genes (DEGs) were identified using the reverse transcription-quantitative polymerase chain reaction, followed by a series of bioinformatic analyses. As a result, there were 448 DEGs, among which 183 (40.85%) were downregulated. The most significant functional terms for the DEGs were the nuclear lumen for cell components (P=2.83×10-4), transcription for biological processes (P=3.7×10-7) and transcription factor activity for molecular functions (P=1.16×104). In total, six significant pathways were enriched, including the most common cancer-associated forkhead box O signaling pathway (P=0.0077), microRNAs in cancer (P=0.0183) and the cAMP signaling pathway (P=0.0415). Furthermore, a network analysis identified three hub genes (HUWE1, PPP1CB and HSPA4), which were all involved in tumor metastasis. Taken together, the DEGs, significant pathways and hub genes identified in the present study shed some light on the molecular mechanisms of ENO1 involved in the pathogenesis of GC.

Global gene expression analysis of knockdown Triosephosphate isomerase (TPI) gene in human gastric cancer cell line MGC-803.

Our preview studies showed TPI gene which encodes the Triosephosphate isomerase was overexpressed in human gastric cancer (GC) tissues. However, the potential molecular mechanisms how TPI influences the GC development is not clear. Here, we performed global gene expression profiling for TPI knockdown using microarrays in human GC cell line MGC-803 cells. The differentially expressed genes (DEGs) were identified using reverse transcription-quantitative polymerase chain reaction analysis. Then the DEGs were analyzed by an online software WebGestalt to perform the functional analysis, pathway analysis and network analysis. The protein-protein interaction (PPI) networks were visualized by Cytoscape and the module analysis was performed by ClusterONE. As a result, a total of 920 DEGs including 197 up- and 723 down-regulated genes were screened out. The DEGs were found to be significantly associated with the metabolic process, biological regulation, protein binding and ion binding. There were 11 significant pathways were enriched, and one of the most significant pathway was transcriptional misregulation in cancer (P<0.01), which contained common cancer-related genes, such as DUSP6, ETV5, IL6, PLAU, PPARG and HMGA2. Two PPI networks were constructed from BioGRID and TCGA_RNASeq_STAD, respectively. One network presented 25 genes with degree >10, and EGFR was the most "hub gene" with degree of 74. Four significant modules were identified and mainly enriched in protein domain of Histone and G-protein beta WD-40 repeat. Another network had 4 significant modules and they were associated with protein domain of MHC class I-like antigen recognition and Epidermal growth factor receptor ligand. In conclusion, DEGs and hub genes identified in the present study help us understand the molecular mechanisms of TPI in the carcinogenesis and progression of gastric cancer.

Role of triosephosphate isomerase and downstream functional genes on gastric cancer.

Triosephosphate isomerase (TPI) is highly expressed in many types of human tumors and is involved in migration and invasion of cancer cells. However, TPI clinicopathological significance and malignant function in gastric cancer (GC) have not been well defined. The present study aimed to examine TPI expression in GC tissue and its biological functions. Furthermore, we investigated its downstream genes by gene chip technology. Our results showed that TPI expression was higher in gastric cancer tissues than adjacent tissues, although no statistical differences were found between TPI expression and clinicopathological factors. TPI overexpression in human gastric carcinoma cell line BGC-823 enhanced cell proliferation, invasion and migration, but did not change cell cycle distribution, while TPI knockdown suppressed proliferation, invasion and migration, induced apoptosis and increased G2/M arrest of human gastric carcinoma cell line MGC-803. Since the cell division cycle associated 5 (CDCA5) was identified as the one with the most decreased expression after TPI knockdown, we investigated its role in MGC-803 cells. The results showed that CDCA5 knockdown also inhibited proliferation, migration, induced apoptosis and increased G2/M arrest similarly to TPI knockdown. CDCA5 overexpression promoted MGC-803 cell proliferation, clone formation and migration abilities. These results indicated that TPI expression level might affect GC cell behavior, suggesting that both TPI and CDCA5 might be considered as potential tumor markers related with GC development and might be potential new targets in GC treatment.

Clinical significance and prognostic value of Triosephosphate isomerase expression in gastric cancer.

Triosephosphate isomerase (TPI) is highly expressed in many human cancers and is involved in migration and invasion of cancer cells. However, TPI clinicopathological significance and prognostic value in gastric cancer (GC) are not yet well defined. The aim of the present work was to evaluate TPI expression in GC tissue and its prognostic value in GC patients.TPI expression was analyzed in 92 primary GC tissues and 80 adjacent normal mucosa tissues from GC patients undergoing gastrectomy by immunohistochemical analysis of tissue microarrays (TMAs). Univariate and multivariate analyses were performed to investigate TPI prognostic significance in GC patients.Immunohistochemical staining score showed that TPI expression in cancer tissues was significantly higher than in adjacent normal mucosa (P < .001). Univariate analysis revealed that TPI expression, depth of invasion, lympho node metastasis, tumor node metastasis (TNM) stage, and tumor diameter were associated with negative prognostic predictors for overall survival in GC patients (P < .05). High TPI expression represented a significant predictor of shorter survival in GC patients with positive lymphatic metastasis (P = .022) and tumor diameter >5 cm (P = .018). Cox multivariate analysis identified TPI expression, TNM stage, and tumor diameter as independent prognostic factors in GC patients.TPI expression might be considered as a novel prognostic factor to evaluate GC patients' survival.

Unsymmetrical oxovanadium complexes derived from salicylaldehyde and phenanthroline: synthesis, DNA interactions, and antitumor activities.

Two unsymmetrical oxovanadium complexes incorporating salicylaldehyde derivate and phenanthroline [VO(DESAA)(phen)] (1), (DESAA = 4-(diethylamino)salicylaldehyde anthranilic acid, phen = phenanthroline) and [VO(CLSAA)(phen)] (2), (CLSAA = 5-chlorosalicylaldehyde anthranilic acid)] have been synthesized and characterized. The interactions of the complexes with CT-DNA were studied using different techniques. Complexes 1 and 2 interact with CT-DNA by intercalative modes and can efficiently cleave pBR322 DNA after light irradiation. The two complexes showed high cytotoxic activities against myeloma cell (Ag8.653) and gliomas cell (U251) lines. Interestingly, complex 1 exhibited greater antitumor efficiency, larger binding affinity with CT-DNA, and better cleaving ability than those of complex 2. In addition, their antitumor mechanism has been analyzed by using cell cycle analysis, apoptosis, and Annexin V-FITC/PI assay. The results showed that complex 1 can cause G2/M-phase arrest of the cell cycle, exhibit a significantly induced apoptosis in Ag8.653 cells, and display typical morphological apoptotic characteristics. These complexes induced proliferative suppression of Ag8.653 cells via the induction of apoptosis.