Doping effect on a two-electron silver nanocluster.

This study investigates the effects of metal addition and doping of a 2-electron silver superatom, [Ag10{S2P(OiPr)2}8] (Ag10). When Ag+ is added to Ag10 in THF solution, [Ag11{S2P(OiPr)2}8(OTf)] (Ag11) is rapidly formed almost quantitatively. When the same method is used with Cu+, a mixture of alloys, [CuxAg11-x{S2P(OiPr)2}8]+ (x = 1-3, CuxAg11-x), is obtained. In contrast, introducing Au+ to Ag10 leads to decomposition. The structural and compositional analysis of Ag11 was characterized by single-crystal X-ray diffraction (SCXRD), ESI-MS, NMR spectroscopy, and DFT calculations. While no crystal structure was obtained for CuxAg11-x, DFT calculations provide insights into potential sites for copper location. The absorption spectrum exhibits a notable blue shift in the low-energy band after copper doping, contrasting with that of the slight shift observed in 8-electron Cu-doped Ag nanoclusters. Ag11 and CuxAg11-x are strongly emissive at room temperature, and solvatochromism across different organic solvents is highlighted. This study underscores the profound influence of metal addition and doping on the structural and optical properties of silver nanoclusters, providing important contributions to understanding the nanoclusters and their photophysical behaviors.

Understanding the AIE phenomenon of nonconjugated rhodamine derivatives via aggregation-induced molecular conformation change.

The bottom-up molecular science research paradigm has greatly propelled the advancement of materials science. However, some organic molecules can exhibit markedly different properties upon aggregation. Understanding the emergence of these properties and structure-property relationship has become a new research hotspot. In this work, by taking the unique closed-form rhodamines-based aggregation-induced emission (AIE) system as model compounds, we investigated their luminescent properties and the underlying mechanism deeply from a top-down viewpoint. Interestingly, the closed-form rhodamine-based AIE system did not display the expected emission behavior under high-viscosity or low-temperature conditions. Alternatively, we finally found that the molecular conformation change upon aggregation induced intramolecular charge transfer emission and played a significant role for the AIE phenomenon of these closed-form rhodamine derivatives. The application of these closed-form rhodamine-based AIE probe in food spoilage detection was also explored.

Highly Selective and Rapid "Turn-On" Fluorogenic Chemosensor for Detection of Salicylic Acid in Plants and Food Samples.

Salicylic acid (SA) is one of the chemical molecules, involved in plant growth and immunity, thereby contributing to the control of pests and pathogens, and even applied in fruit and vegetable preservation. However, only a few tools have ever been designed or executed to understand the physiological processes induced by SA or its function in plant immunity and residue detection in food. Hence, three Rh6G-based fluorogenic chemosensors were synthesized to detect phytohormone SA based on the "OFF-ON" mechanism. The probes showed high selectivity, ultrafast response time (<60 s), and nanomolar detection limit for SA. Moreover, the probe possessed outstanding profiling that can be successfully used for SA imaging of callus and plants. Furthermore, the fluorescence pattern indicated that SA could occur in the distal transport in plants. These remarkable results contribute to improving our understanding of the multiple physiological and pathological processes involved in SA for plant disease diagnosis and for the development of immune activators. In addition, SA detection in some agricultural products used probes to extend the practical application because its use is prohibited in some countries and is harmful to SA-sensitized persons. Interestingly, the as-obtained test paper displayed that SA could be imaged by ultraviolet (UV) and was directly visible to the naked eye. Given the above outcomes, these probes could be used to monitor SA in vitro and in vivo, including, but not limited to, plant biology, food residue detection, and sewage detection.

The PrLGlu→avBNSTGABA circuit rapidly modulates depression-like behaviors in male mice.

Depression is a global disease with a high prevalence. Here, we examine the role of the circuit from prelimbic mPFC (PrL) to the anterior ventral bed nucleus of the stria terminalis (avBNST) in depression-like mice through behavioral tests, immunofluorescence, chemogenetics, optogenetics, pharmacology, and fiber photometry. Mice exposed to chronic restraint stress with individual housing displayed depression-like behaviors. Optogenetic or chemogenetic activation of the avBNST-projecting glutamatergic neurons in the PrL had an antidepressant effect. Moreover, we found that α-amino-3-hydroxy-5-methyl-4-isoxazole-propionicacid receptors (AMPARs) play a dominant role in this circuit. Systemic administration of ketamine profoundly alleviated depression-like behaviors in the mice and rapidly rescued the decreased activity in the PrLGlu→avBNSTGABA circuit. Furthermore, the fast-acting effect of ketamine on depressive behaviors was diminished when the circuit was inhibited. To summarize, activating the PrLGlu→avBNSTGABA circuit quickly ameliorated depression-like behaviors. Thus, we propose the PrLGlu→avBNSTGABA circuit as a target for fast regulation of depression.

Rhodamine-based fluorescent sensors for the rapid and selective off-on detection of salicylic acid and their use in plant cell imaging.

Salicylic acid (SA) is a key hormone that regulates plant growth and immunity, and understanding the physiologic processes induced by SA enables the development of highly pathogen-resistant crops. Here, we report the synthesis of three new SA-sensors (R1-R3) from hydroxyphenol derivatives of a rhodamine-acylhydrazone scaffold and their characterization by NMR and HRMS. Spectroscopic analyses revealed that structural variations in R1-R3 resulted in sensors with different sensitivities for SA. Sensor R2 (with the 3-hydroxyphenyl modification) outperformed R1 (2-hydroxyphenyl) and R3 (4-hydroxyphenyl). The SA-detection limit of R2 is 0.9 µM with an ultra-fast response time (<60 s). In addition, their plant imaging indicated that designed sensor R2 is useful for the further study of SA biology and the discovery and development of new inducers of plant immunity.

Hydride Doping Effects on the Structure and Properties of Eight-Electron Rh/Ag Superatoms: The [RhHx@Ag21-x{S2P(OnPr)2}12] (x = 0-2) Series.

Three hitherto unknown eight-electron rhodium/silver alloy nanoclusters, [RhAg21{S2P(OnPr)2}12] (1), [RhHAg20{S2P(OnPr)2}12] (2), and [RhH2Ag19{S2P(OnPr)2}12] (3), have been isolated and fully characterized. Cluster 1 contains a regular Rh@Ag12 icosahedral core, whereas 2 and 3 exhibit distorted RhH@Ag12 and RhH2@Ag12 icosahedral cores. The single-crystal neutron structure of 2 located the encapsulated hydride at the center of an enlarged RhAg3 tetrahedron. A similar position was found by neutron diffraction for one of the hydrides in 3, whereas the other hydride is trigonally coordinated to Rh and an elongated Ag-Ag edge. The solid-state structures of 1-3 possess C1 symmetry due to the asymmetric arrangement of the surrounding capping Ag atoms. Our investigation shows that the insertion of one hydride dopant provokes the elimination of one capping silver atom on the cluster surface, resulting in the general formula [RhHx@Ag21-x{S2P(OnPr)2}12] (x = 0-2), which maintains the same number of cluster electrons as well as neutral charge. Clusters 1-3 exhibit an intense emission band in the NIR region. Contrarily to their PdAg21 and PdHAg20 relatives, the 4d orbitals of the encapsulated heterometal are somewhat involved in the optical processes.

Fructose Metabolism in Tumor Endothelial Cells Promotes Angiogenesis by Activating AMPK Signaling and Mitochondrial Respiration.

Angiogenesis is vital for tumor growth and metastasis. Emerging evidence suggests that metabolic reprogramming in endothelial cells (EC) may affect angiogenesis. Here, we showed that multiple regulators in the fructose metabolism pathway, especially fructose transporter SLC2A5 and fructose-metabolizing enzyme ketohexokinase (KHK), were upregulated in tumor endothelial cells from hepatocellular carcinoma (HCC). In mouse models with hepatoma xenografts or with Myc/sgp53-induced liver cancer, dietary fructose enhanced tumor angiogenesis, tumor growth, and metastasis, which could be attenuated by treatment with an inhibitor of SLC2A5. Furthermore, vessel growth was substantially increased in fructose-containing Matrigel compared with PBS-Matrigel. Inhibiting fructose metabolism in EC cells in vivo using EC-targeted nanoparticles loaded with siRNA against KHK significantly abolished fructose-induced tumor angiogenesis. Fructose treatment promoted the proliferation, migration, and tube formation of ECs and stimulated mitochondrial respiration and ATP production. Elevated fructose metabolism activated AMPK to fuel mitochondrial respiration, resulting in enhanced EC migration. Fructose metabolism was increased under hypoxic conditions as a result of HIF1α-mediated upregulation of multiple genes in the fructose metabolism pathway. These findings highlight the significance of fructose metabolism in ECs for promoting tumor angiogenesis. Restricting fructose intake or targeting fructose metabolism is a potential strategy to reduce angiogenesis and suppress tumor growth. SIGNIFICANCE: Fructose metabolism in endothelial cells fuels mitochondrial respiration to stimulate tumor angiogenesis, revealing fructose metabolism as a therapeutic target and fructose restriction as a dietary intervention for treating cancer.

Promoting effect of Fe3+ on gentamicin resistance in Escherichia coli.

Kinds of antibiotics are used to prevent and control bacteria infections, unfortunately, the overuse and misuse of antibiotic have promoted the emergence and spread of antibiotic-resistant bacteria. Therefore, understanding the mechanism of antibiotic resistance is very important. This study explores the combined effection of metal ions and antibiotic to the drug resistance of Escherichia coli. Our results found that the minimum inhibitory concentration (MIC) increased as the ammonium ferric citrate concentration increased, especially for gentamicin antibiotic. When the Fe3+ concentration reached 300 µM, the survival of E. coli was stably restored with the increased gentamicin concentration. Exogenous Fe3+ could decrease intracellular gentamicin concentration. On the other hand, Fe3+ treatment together with gentamicin could reduce reactive oxygen species (ROS) production, characterized by decreased levels of NADH and ATP. Furthermore, ROS-scavenging enzymes of superoxide dismutase (SOD) and catalase (CAT) were up-regulated and H2O2 plus gentamicin-mediated killing was restored by Fe3+. These results may have significant implications in understanding bacterial antibiotic-resistant mechanisms based on the external Fe3+ concentration.

Dual and opposing roles of the androgen receptor in VETC-dependent and invasion-dependent metastasis of hepatocellular carcinoma.

BACKGROUND & AIMS: Contradictory roles of the androgen receptor (AR) in hepatocellular carcinoma (HCC) metastasis have been reported. We have shown that VETC (vessels encapsulating tumor clusters) mediates invasion-independent metastasis, whereas VETC- HCCs metastasize in an invasion-dependent manner. Herein, we aimed to reveal the roles of AR in HCC metastasis. METHODS: Mouse xenograft models, clinical samples, and cell models were used. RESULTS: AR expression was significantly lower in HCCs with a VETC pattern, portal vein tumor thrombus, endothelium-coated microemboli or high recurrence rates. Overexpressing AR in VETC+ hepatoma cells suppressed VETC formation and intrahepatic metastasis but promoted pulmonary metastasis of mouse xenografts. AR decreased the transcription of Angiopoietin-2 (Angpt2), a factor essential for VETC formation, by binding to the Angpt2 promoter. The roles of AR in inhibiting VETC formation and intrahepatic metastasis were attenuated by restoring Angpt2 expression, suggesting that AR may repress VETC-dependent intrahepatic metastasis by inhibiting Angpt2 expression and VETC formation. On the other hand, AR upregulated Rac1 expression, promoted lamellipodia formation and increased cell migration/invasion. A Rac1 inhibitor abrogated the AR-mediated promotion of migration/invasion and pulmonary metastasis of VETC+ hepatoma cells, but did not affect the AR-mediated inhibition of intrahepatic metastasis. Furthermore, an AR inhibitor decreased Rac1 expression and attenuated both intrahepatic and pulmonary metastasis of VETC- xenografts, an effect which was abrogated by restoring Rac1 expression. These data indicate that AR may facilitate the lung metastasis of VETC+ HCCs and both the liver/lung metastases of VETC- HCCs by upregulating Rac1 expression and then promoting migration/invasion. CONCLUSION: AR plays dual and opposing roles in VETC-dependent and invasion-dependent metastasis, which highlights the complex functions of AR and the importance of individualized cancer therapy. LAY SUMMARY: In this study, we uncovered the dual and opposing roles of the androgen receptor in VETC (vessels encapsulating tumor clusters)-dependent and invasion-dependent metastasis of hepatocellular carcinoma (HCC). We elucidated the underlying mechanisms of these processes, which provided novel insights into the complex regulatory network of the androgen receptor in HCC metastasis and may have important implications for precision medicine.

Predictive value of K-ras and PIK3CA in non-small cell lung cancer patients treated with EGFR-TKIs: a systemic review and meta-analysis.

OBJECTIVE: A meta-analysis was performed to augment the insufficient data on the impact of mutative EGFR downstream phosphatidylinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways on the clinical efficiency of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) treatment of non-small cell lung cancer (NSCLC) patients. METHODS: Network databases were explored in April, 2015. Papers that investigated the clinical outcomes of NSCLC patients treated with EGFR-TKIs according to the status of K-ras and/or PIK3CA gene mutation were included. A quantitative meta-analysis was conducted using standard statistical methods. Odds ratios (ORs) for objective response rate (ORR) and hazard ratios (HRs) for progression-free survival (PFS) and overall survival (OS) were calculated. RESULTS: Mutation in K-ras significantly predicted poor ORR [OR =0.22; 95% confidence interval (CI), 0.13-0.35], shorter PFS (HR =1.56; 95% CI, 1.27-1.92), and shorter OS (HR =1.59; 95% CI, 1.33-1.91) in NSCLC patients treated with EGFR-TKIs. Mutant PIK3CA significantly predicted shorter OS (HR =1.83; 95% CI, 1.05-3.20), showed poor ORR (OR =0.70; 95% CI, 0.22-2.18), and shorter PFS (HR =1.79; 95% CI, 0.91-3.53) in NSCLC patients treated with EGFR-TKIs. CONCLUSION: K-ras mutation adversely affected the clinical response and survival of NSCLC patients treated with EGFR-TKIs. PIK3CA mutation showed similar trends. In addition to EGFR, adding K-ras and PIK3CA as routine gene biomarkers in clinical genetic analysis is valuable to optimize the effectiveness of EGFR-TKI regimens and identify optimal patients who will benefit from EGFR-TKI treatment.