GPX3-Mediated Oxidative Stress Affects Pyrimidine Metabolism Levels in Stomach Adenocarcinoma via the AMPK/mTOR Pathway.

Background: Amino acid metabolism, including ATP production, nucleotide synthesis, and redox homeostatic processes, are associated with proliferation and differentiation of tumor cells. This study aimed to identify novel prognostic biomarkers and potential therapeutic targets of amino acid metabolism-related genes for stomach adenocarcinoma (STAD). Methods: RNA sequencing transcriptome data in the TCGA-STAD (training set) and GTEx datasets (validation set) were used. The LIMMA R program enabled the differentially expressed amino acid metabolism-related genes (AAMRGs) to be found. A prognostic risk score model based on clinical phenotypic features was built using LASSO regression and step multi-Cox analyses. Gene set enrichment analysis (GSEA) was used to find potential molecular pathways associated with STAD. Hierarchical cluster analysis was used to evaluate pyrimidine metabolism. Cultured STAD cells assessed the proliferation of STAD and upregulation of GPX3 expression by CCK8 and flow cytometry. Transwell and wound healing assays assessed the impact of GPX3 on invasion and migration of STAD cells. Western blot and qRT-PCR were used to measure changes in pyrimidine metabolism-related markers and active molecules involved in the AMPK/mTOR signaling pathway. Results: Three AAMRGs, DNMT1, F2R, and GPX3, could independently predict the course of STAD. Pyrimidine metabolism appeared to be significantly associated with these by GSEA and clustering analyses. Pyrimidine metabolism was negatively correlated with GPX3. Functional studies using an overexpressed GPX3 plasmid showed an enhanced migration and invasion of STAD cells as well as the expression of genes associated with pyrimidine metabolism and the AMPK/mTOR signaling pathway. By using a CAD siRNA, it was found that that GPX3 affected 5-fluorouracil resistance during de novo synthesis of pyrimidine through the CAD-UMPS signaling axis. Conclusions: GPX3 which regulates the level of pyrimidine metabolism through the AMPK/mTOR pathway was found to be closely associated with STAD. Our findings demonstrate GPX3 is a reliable biomarker for the prognosis of amino acid metabolism and a probable target for STAD therapy.

Clinical significance of DTX2 expression in clear cell renal cell carcinoma tissues and its effect on renal cancer cell proliferation, migration and invasion based on TCGA database / 中国肿瘤生物治疗杂志

@#[摘 要] 目的：基于TCGA数据库分析Deltex E3泛素连接酶2（DTX2）在肾透明细胞癌（ccRCC）组织中的表达水平及临床意义，探讨DTX2对ccRCC细胞增殖、迁移和侵袭的影响。方法：利用TIMER数据库分析DTX2在泛癌组织中的表达水平，通过UALCAN数据库进一步验证ccRCC组织和癌旁组织中DTX2 mRNA和蛋白表达差异。使用UALCAN数据库中的TCGA-ccRCC队列数据集，分析ccRCC中DTX2表达与患者临床病理特征的相关性。通过K-M plot数据库分析DTX2表达与ccRCC患者预后的相关性。利用DAVID数据库对DTX2相关基因进行GO和KEGG通路富集分析。通过qPCR法检测DTX2基因在人胚肾293（HEK293）细胞和ccRCC细胞A498、Caki-1中的表达水平。利用siRNA技术分别将DTX2 siRNA及其阴性对照质粒转入A498、Caki-1细胞，采用CCK-8法、平板克隆实验、划痕实验及Transwell侵袭实验分别检测敲低DTX2对细胞增殖、迁移和侵袭的影响。结果：TCGA数据库分析结果表明，与癌旁组织相比，ccRCC组织中DTX2 mRNA和蛋白均呈高表达（均P<0.01）。DTX2表达水平与ccRCC患者的病理分期、临床分级、不同亚型和淋巴结转移相关联（均P<0.01），DTX2高表达与患者的不良预后具有相关性（均P<0.01）。GO功能和KEGG通路富集分析结果显示，DTX2表达相关基因主要参与蛋白酶体介导的泛素依赖性蛋白质分解代谢等生物学过程，并主要富集到了mTOR信号通路等与肿瘤的相关信号通路中（均P<0.05）。体外细胞实验结果表明，A498和Caki-1细胞中DTX2表达水平高于HEK293细胞；敲低DTX2表达可显著降低A498和Caki-1细胞的增殖、迁移及侵袭能力（均P<0.01）。结论：DTX2在ccRCC组织和细胞中呈高表达，其高表达患者的预后较差。敲低DTX2表达可抑制ccRCC细胞增殖、迁移和侵袭，DTX2有望成为ccRCC新的生物标志物和治疗靶点。

Multiomics Analysis of TMEM200A as a Pan-Cancer Biomarker.

The transmembrane protein, TMEM200A, is known to be associated with human cancers and immune infiltration. Here, we assessed the function of TMEM200A in common cancers by multiomics analysis and used in vitro cell cultures of gastric cells to verify the results. The expression of TMEM200A in several human cancer types was assessed using the RNA-seq data from the UCSC Xena database. Bioinformatic analysis revealed a potential role of TMEM200A as a diagnostic and prognostic biomarker. Cultures of normal gastric and cancer cell lines were grown and TMEM200A was knocked down. The expression levels of TMEM200A were measured by using quantitative real-time polymerase chain reaction and western blotting. In vitro loss-of-function studies were then used to determine the roles of TMEM200A in the malignant behavior and tumor formation of gastric cancer (GC) cells. Western blots were used to assess the effect of the knockdown on epithelial-mesenchymal transition (EMT) and PI3K/AKT signaling pathway in GC. Bioinformatic analysis showed that TMEM200A was expressed at high levels in GC. The proliferation of GC cells was inhibited by TMEM200A knockdown, which also decreased vimentin, N-cadherin, and Snai proteins, and inhibited AKT phosphorylation. The PI3K/AKT signaling pathway also appeared to be involved in TMEM200A-mediated regulation of GC development. The results presented here suggest that TMEM200A regulates the tumor microenvironment by affecting the EMT. TMEM200A may also affect EMT through PI3K/AKT signaling, thus influencing the tumor microenvironment. Therefore, in pan-cancers, especially GC, TMEM200A may be a potential biomarker and oncogene.

Electro-thermal actuation in percolative ferroelectric polymer nanocomposites.

The interconversion between electrical and mechanical energies is pivotal to ferroelectrics to enable their applications in transducers, actuators and sensors. Ferroelectric polymers exhibit a giant electric-field-induced strain (>4.0%), markedly exceeding the actuation strain (≤1.7%) of piezoelectric ceramics and crystals. However, their normalized elastic energy densities remain orders of magnitude smaller than those of piezoelectric ceramics and crystals, severely limiting their practical applications in soft actuators. Here we report the use of electro-thermally induced ferroelectric phase transition in percolative ferroelectric polymer nanocomposites to achieve high strain performance in electric-field-driven actuation materials. We demonstrate a strain of over 8% and an output mechanical energy density of 11.3 J cm-3 at an electric field of 40 MV m-1 in the composite, outperforming the benchmark relaxor single-crystal ferroelectrics. This approach overcomes the trade-off between mechanical modulus and electro-strains in conventional piezoelectric polymer composites and opens up an avenue for high-performance ferroelectric actuators.

Malonylation of Acetyl-CoA carboxylase 1 promotes hepatic steatosis and is attenuated by ketogenic diet in NAFLD.

Protein post-translational modifications (PTMs) participate in important bioactive regulatory processes and therefore can help elucidate the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Here, we investigate the involvement of PTMs in ketogenic diet (KD)-improved fatty liver by multi-omics and reveal a core target of lysine malonylation, acetyl-coenzyme A (CoA) carboxylase 1 (ACC1). ACC1 protein levels and Lys1523 malonylation are significantly decreased by KD. A malonylation-mimic mutant of ACC1 increases its enzyme activity and stability to promote hepatic steatosis, whereas the malonylation-null mutant upregulates the ubiquitination degradation of ACC1. A customized Lys1523ACC1 malonylation antibody confirms the increased malonylation of ACC1 in the NAFLD samples. Overall, the lysine malonylation of ACC1 is attenuated by KD in NAFLD and plays an important role in promoting hepatic steatosis. Malonylation is critical for ACC1 activity and stability, highlighting the anti-malonylation effect of ACC1 as a potential strategy for treating NAFLD.

An Electrochemical Nanosensor for Monitoring the Dynamics of Intracellular H2 O2 Upon NADH Treatment.

Reactive oxygen species (ROS)-based therapeutic strategies play an important role in cancer treatment. However, in situ, real-time and quantitative analysis of intracellular ROS in cancer treatment for drug screening is still a challenge. Herein we report one selective hydrogen peroxide (H2 O2 ) electrochemical nanosensor, which is prepared by electrodeposition of Prussian blue (PB) and polyethylenedioxythiophene (PEDOT) onto carbon fiber nanoelectrode. With the nanosensor, we find that the level of intracellular H2 O2 increases with NADH treatment and that increase is dose-dependent to the concentration of NADH. High-dose of NADH (above 10 mM) can induce cell death and intratumoral injection of NADH is validated for inhibiting tumor growth in mice. This study highlights the potential of electrochemical nanosensor for tracking and understanding the role of H2 O2 in screening new anticancer drug.

Relaxor ferroelectric polymer exhibits ultrahigh electromechanical coupling at low electric field.

Electromechanical (EM) coupling-the conversion of energy between electric and mechanical forms-in ferroelectrics has been used for a broad range of applications. Ferroelectric polymers have weak EM coupling that severely limits their usefulness for applications. We introduced a small amount of fluorinated alkyne (FA) monomers (<2 mol %) in relaxor ferroelectric poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (PVDF-TrFE-CFE) terpolymer that markedly enhances the polarization change with strong EM coupling while suppressing other polarization changes that do not contribute to it. Under a low-dc bias field of 40 megavolts per meter, the relaxor tetrapolymer has an EM coupling factor (k33) of 88% and a piezoelectric coefficient (d33) >1000 picometers per volt. These values make this solution-processed polymer competitive with ceramic oxide piezoelectrics, with the potential for use in distinct applications.

High-entropy polymer produces a giant electrocaloric effect at low fields.

More than a decade of research on the electrocaloric (EC) effect has resulted in EC materials and EC multilayer chips that satisfy a minimum EC temperature change of 5 K required for caloric heat pumps1-3. However, these EC temperature changes are generated through the application of high electric fields4-8 (close to their dielectric breakdown strengths), which result in rapid degradation and fatigue of EC performance. Here we report a class of EC polymer that exhibits an EC entropy change of 37.5 J kg-1 K-1 and a temperature change of 7.5 K under 50 MV m-1, a 275% enhancement over the state-of-the-art EC polymers under the same field strength. We show that converting a small number of the chlorofluoroethylene groups in poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) terpolymer into covalent double bonds markedly increases the number of the polar entities and enhances the polar-nonpolar interfacial areas of the polymer. The polar phases in the polymer adopt a loosely correlated, high-entropy state with a low energy barrier for electric-field-induced switching. The polymer maintains performance for more than one million cycles at the low fields necessary for practical EC cooling applications, suggesting that this strategy may yield materials suitable for use in caloric heat pumps.

Co@C Nanoparticle Embedded Hierarchically Porous N-Doped Hollow Carbon for Efficient Oxygen Reduction.

The rational construction of highly active and stable non-noble metal electrocatalysts for the oxygen reduction reaction (ORR) is an ongoing challenge for practical applications of catalysts. Here, we report a novel nanostructured hollow N-doped carbon hybrid through pyrolysis of silica@CoZn-coordinated zeolitic imidazolate frameworks. The carbon layer encased cobalt nanoparticles were embedded in the hierarchically porous carbon catalyst (Co@C-HN-hC). Profiting from the synergistic effect between highly active Co@C NPs and HN-hC, the Co@C-HN-hC catalyst exhibited remarkable catalytic performances as compared to porous N-doped hollow carbon (N-hC) and N-doped carbon encased Co NPs (Co@N-C). The electrochemical measurements show that the performances of the Co@C-HN-hC catalyst is close to that of the Pt/C catalysts, along with an excellent stability and durability in the ORR process. This study provides a guideline for controllable design of carbon-based ORR catalysts for substituting noble metal catalysts.