Identifying and validating angiogenesis-related genes remodeling tumor microenvironment and suppressing immunotherapy response in gastric cancer.

Angiogenesis significantly correlates with tumor microenvironment remodeling and immunotherapy response. Our study aimed to construct a prognostic angiogenesis-related model for gastric cancer. Using public database, a angiogenetic related five-gene (FGF1, GRB14, PAK3, PDGFRA, and PRKD1) model was identified. The top 25 % of patients were defined as high-risk, and the remaining as low-risk. The area under the curve for 1-, 3-, and 5-year overall survival (OS) were 0.646, 0.711, and 0.793, respectively. Survival analysis showed a better 10-year OS in low-risk patients in the construction (HR = 0.57, p = 0.002) and validation cohorts. GO and GSEA revealed that DEGs were enriched in extracellular matrix receptor interactions, dendritic cell antigen processing/presentation regulation, and angiogenesis pathways. CIBERSORT analysis revealed abundant naïve B cells, resting mast cells, resting CD4+ memory T cells, M2 macrophages, and monocytes in high-risk subgroups. The TIMER database showed strong positive correlations between PAK3, FGF1, PRKD1, and PDGFRA expression levels and the infiltration of CD4+ T cells and macrophages. The IOBR analysis revealed an immunosuppressive environment in the high-risk subgroup. Low-risk patients show a higher response rate to anti-PD1 treatment. TMA showed that FGF1 overexpression was associated with poor prognosis and CD4+ T cells and macrophage infiltration. In vivo study based on the 615 mice indicated that inhibiting FGF1 function could suppress tumor growth and enhance anti-PD1 therapeutic efficacy. In summary, we established a five-angiogenesis-related gene model to predict survival outcomes and immunotherapy responses in patients with gastric cancer and identified FGF1 as a prognostic gene and potential target for improving immune treatment.

Diverse associations between pancreatic intra-, inter-lobular fat and the development of type 2 diabetes in overweight or obese patients.

Pancreatic fat is associated with obesity and type 2 diabetes mellitus (T2DM); however, the relationship between different types of pancreatic fat and diabetes status remains unclear. Therefore, we aimed to determine the potential of different types of pancreatic fat accumulation as a risk factor for T2DM in overweight or obese patients. In total, 104 overweight or obese patients were recruited from January 2020 to December 2022. The patients were divided into three groups: normal glucose tolerance (NGT), impaired fasting glucose or glucose tolerance (IFG/IGT), and T2DM. mDixon magnetic resonance imaging (MRI) was used to detect pancreatic fat in all three groups of patients. The pancreatic head fat (PHF), body fat (PBF), and tail fat (PTF) in the IFG/IGT group were 21, 20, and 31% more than those in the NGT group, respectively. PHF, PBF, and PTF were positively associated with glucose metabolic dysfunction markers in the NGT group, and inter-lobular fat volume (IFV) was positively associated with these markers in the IFG/IGT group. The areas under the receiver operating characteristic curves for PHF, PBF, and PTF (used to evaluate their diagnostic potential for glucose metabolic dysfunction) were 0.73, 0.73, and 0.78, respectively, while those for total pancreatic volume (TPV), pancreatic parenchymal volume, IFV, and IFV/TPV were 0.67, 0.67, 0.66, and 0.66, respectively. These results indicate that intra-lobular pancreatic fat, including PHF, PTF, and PBF, may be a potential independent risk factor for the development of T2DM. Additionally, IFV exacerbates glucose metabolic dysfunction. Intra-lobular pancreatic fat indices were better than IFV for the diagnosis of glucose metabolic dysfunction.

Reactions of Cisplatin with Thioredoxin-1 Regulate Intracellular Redox Homeostasis.

Cisplatin is a widely used anticancer drug. In addition to inducing DNA damage, increased levels of reactive oxygen species (ROS) play a significant role in cisplatin-induced cell death. Thioredoxin-1 (Trx1), a redox regulatory protein that can scavenge ROS, has been found to eliminate cisplatin-induced ROS, while elevated Trx1 levels are associated with cisplatin resistance. However, it is unknown whether the effect of Trx1 on the cellular response to cisplatin is due to its direct reaction and how this reaction influences the activity of Trx1. In this work, we performed detailed studies of the reaction between Trx1 and cisplatin. Trx1 is highly reactive to cisplatin, and the catalytic motif of Trx1 (CGPC) is the primary binding site of cisplatin. Trx1 can bind up to 6 platinum moieties, resulting in the structural alteration and oligomerization of Trx1 depending on the degree of platination. Platination of Trx1 inhibits its interaction with ASK1, a Trx1-binding protein that regulates cell apoptosis. Furthermore, the reaction with cisplatin suppresses drug-induced ROS generation, which could be associated with drug resistance. This study provides more insight into the mechanism of action of cisplatin.

Enhancing Tumor Immunotherapy by Multivalent Anti-PD-L1 Nanobody Assembled via Ferritin Nanocage.

Increasing immunotherapy response rate and durability can lead to significant improvements in cancer care. To address this challenge, a novel multivalent immune checkpoint therapeutic platform is constructed through site-specific ligation of anti-PD-L1 nanobody (Nb) on ferritin (Ftn) nanocage. Nb-Ftn blocks PD-1/PD-L1 interaction and downregulates PD-L1 levels via endocytosis-induced degradation. In addition, the cage structure of Ftn allows encapsulation of indocyanine green (ICG), an FDA-approved dye. Photothermal treatment with Nb-Ftn@ICG induces immunogenic death of tumor cells, which improves systemic immune response via maturation of dendritic cells and enhanced infiltration of T cells. Moreover, Nb-Ftn encapsulation significantly enhances cellular uptake, tumor accumulation and retention of ICG. In vivo assays showed that this nanoplatform ablates the primary tumor, suppresses abscopal tumors and inhibits tumor metastasis, leading to a prolonged survival rate. This work presents a novel strategy for improving cancer immunotherapy using multivalent nanobody-ferritin conjugates as immunological targeting and enhancing carriers.

Mutual promotion of co-condensation of KRAS G-quadruplex and a well-folded protein HMGB1.

Liquid-liquid phase separation (LLPS) of G-quadruplex (GQ) is involved in many crucial cellular processes, while the quadruplex-folding and their functions are typically modulated by specific DNA-binding proteins. However, the regulatory mechanism of binding proteins, particularly the well-folded proteins, on the LLPS of GQs is largely unknown. Here, we investigated the effect of HMGB1 on the condensation of a G-quadruplex of KRAS promoter (GQKRAS). The results show that these two rigid macro-biomolecules undergo co-condensation through a mutual promotion manner, while neither of them can form LLPS alone. Fluidity measurements confirm that the liquid-like droplets are highly dynamic. HMGB1 facilitates and stabilizes the quadruplex folding of GQKRAS, and this process enhances their co-condensation. The KRAS promoter DNA retains quadruplex folding in the droplets; interference with the GQ-folding disrupts the co-condensation of GQKRAS/HMGB1. Mechanistic studies reveal that electrostatic interaction is a key driving force of the interaction and co-condensation of GQKRAS/HMGB1; meanwhile, the recognition of two macro-biomolecules plays a crucial role in this process. This result indicates that the phase separation of GQs can be modulated by DNA binding proteins, and this process could also be an efficient way to recruit specific DNA binding proteins.

Peroxide-Simulating and GSH-Depleting Nanozyme for Enhanced Chemodynamic/Photodynamic Therapy via Induction of Multisource ROS.

Reactive oxygen species (ROS) generation, using photodynamic therapy (PDT) and chemodynamic therapy (CDT), is a promising strategy for cancer treatment. However, the production of ROS in tumor cells is often limited by hypoxia, insufficient substrates, and high level of ROS scavengers in a tumor microenvironment, which seriously affects the efficacy of ROS-related tumor therapies. Herein, we report a lipid-supported manganese oxide nanozyme, MLP@DHA&Ce6, by decorating a MnO2 nano-shell on the liposome loaded with dihydroartemisinin (DHA) and photosensitizer Ce6 for generating multisource ROS to enhance cancer therapy. MLP@DHA&Ce6 can be accumulated in tumors and can release active components, Mn2+ ions, and O2. The conjugate generates ROS via nanozyme-catalyzed CDT using DHA as a substrate, PDT through Ce6, and the Fenton reaction catalyzed by Mn2+ ions. The production of O2 from MnO2 enhanced Ce6-mediated PDT under near-infrared light irradiation. Meanwhile, MLP@DHA&Ce6 showed prominent glutathione depletion, which allowed ROS to retain high activity in tumor cells. In addition, the release of Mn2+ ions and DHA in tumor cells induced ferroptosis. This multisource ROS generation and ferroptosis effect of MLP@DHA&Ce6 led to enhanced therapeutic effects in vivo.

Cellular uptake of nickel by NikR is regulated by phase separation.

Bacterial cells were long thought to be "bags of enzymes" with minimal internal structures. In recent years, membrane-less organelles formed by liquid-liquid phase separation (LLPS) of proteins or nucleic acids have been found to be involved in many important biological processes, although most of them were studied on eukaryotic cells. Here, we report that NikR, a bacterial nickel-responsive regulatory protein, exhibits LLPS both in solution and inside cells. Analyses of cellular nickel uptake and cell growth of E. coli confirm that LLPS enhances the regulatory function of NikR, while disruption of LLPS in cells promotes the expression of nickel transporter (nik) genes, which are negatively regulated by NikR. Mechanistic study shows that Ni(II) ions induces the accumulation of nik promoter DNA into the condensates formed by NikR. This result suggests that the formation of membrane-less compartments can be a regulatory mechanism of metal transporter proteins in bacterial cells.

Cisplatin reacts with the RING finger domain of RNF11 and interferes with the protein functions.

Protein reactions play important roles in the mechanism of action of cisplatin. In this work, we found that cisplatin is highly reactive to the RING finger domain of RNF11, a key protein involved in tumorigenesis and metastasis. The results show that cisplatin binds to RNF11 at the zinc coordination site and leads to zinc ejection from the protein. The formation of S-Pt(II) coordination and Zn(II) ions release have been confirmed by UV-vis spectrometry using zinc dye and thiol agent, showing reducing the contents of thiol groups while forming S-Pt bonds and releasing zinc ions. Electrospray ionization-mass spectrometry measurement indicates that each RNF11 can bind up to three platinum atoms. Kinetical analysis shows a reasonable platination rate of RNF11 with t1/2 ∼ 3 h. CD, nuclear magnetic resonance, and gel electrophoresis measurements indicate that the cisplatin reaction causes protein unfolding and oligomerization of RNF11. Pull-down assay confirms that the platination of RNF11 interferes with the protein interaction of RNF11 with UBE2N, a key step of the functionalization of RNF11. Furthermore, Cu(I) was found to promote the platination of RNF11, which could lead to increased protein reactivity to cisplatin in tumor cells with high copper levels. These results indicate that the platination-induced zinc release of RNF11 disrupts the protein structure and interferes with its functions.

Metabolite profiling and identification in living cells by coupling stable isotope tracing and induced electrospray mass spectrometry.

Direct observation of metabolites in living cells by mass spectrometry offers a bright future for biological studies but also suffers a severe challenge to untargeted peak assignment to tentative metabolite candidates. In this study, we developed a method combining stable isotope tracing and induced electrospray mass spectrometry for living-cells metabolite measurement and identification. By using 13C6-glucose and ammonium chloride-15N as the sole carbon and nitrogen sources for cell culture, Escherichia coli synthesized metabolites with 15N and 13C elements. Tracing the number of carbon and nitrogen atoms could offer a complementary dimension for candidate peak searching. As a result, the identification confidence of metabolites achieved a universal improvement based on carbon/nitrogen labelling and filtration.

α-Synuclein as a Target for Metallo-Anti-Neurodegenerative Agents.

The unique thermodynamic and kinetic coordination chemistry of ruthenium allows it to modulate key adverse aggregation and membrane interactions of α-synuclein (α-syn) associated with Parkinson's disease. We show that the low-toxic RuIII complex trans-[ImH][RuCl4 (Me2 SO)(Im)] (NAMI-A) has dual inhibitory effects on both aggregation and membrane interactions of α-syn with submicromolar affinity, and disassembles pre-formed fibrils. NAMI-A abolishes the cytotoxicity of α-syn towards neuronal cells and mitigates neurodegeneration and motor impairments in a rat model of Parkinson's. Multinuclear NMR and MS analyses show that NAMI-A binds to residues involved in protein aggregation and membrane binding. NMR studies reveal the key steps in pro-drug activation and the effect of activated NAMI-A species on protein folding. Our findings provide a new basis for designing ruthenium complexes which could mitigate α-syn-induced Parkinson's pathology differently from organic agents.