Structure-specific nucleases: role in Okazaki fragment maturation.

Proper function of structure-specific nucleases is key for faithful Okazaki fragment maturation (OFM) process completion. Deregulation of such nucleases leads to aberrant OFM and causes a spectrum of mutations, some of which may confer survival outcomes under specific stresses and serve as attractive targets for therapeutic intervention in human cancers.

Symmetric control of sister chromatid cohesion establishment.

Besides entrapping sister chromatids, cohesin drives other high-order chromosomal structural dynamics like looping, compartmentalization and condensation. ESCO2 acetylates a subset of cohesin so that cohesion must be established and only be established between nascent sister chromatids. How this process is precisely achieved remains unknown. Here, we report that GSK3 family kinases provide higher hierarchical control through an ESCO2 regulator, CRL4MMS22L. GSK3s phosphorylate Thr105 in MMS22L, resulting in homo-dimerization of CRL4MMS22L and ESCO2 during S phase as evidenced by single-molecule spectroscopy and several biochemical approaches. A single phospho-mimicking mutation on MMS22L (T105D) is sufficient to mediate their dimerization and rescue the cohesion defects caused by GSK3 or MMS22L depletion, whereas non-phosphorylable T105A exerts dominant-negative effects even in wildtype cells. Through cell fractionation and time-course measurements, we show that GSK3s facilitate the timely chromatin association of MMS22L and ESCO2 and subsequently SMC3 acetylation. The necessity of ESCO2 dimerization implicates symmetric control of cohesion establishment in eukaryotes.

Integrated metagenomic and metabolomic analysis reveals distinctive stage-specific gut-microbiome-derived metabolites in intracranial aneurysms.

OBJECTIVE: Our study aimed to explore the influence of gut microbiota and their metabolites on intracranial aneurysms (IA) progression and pinpoint-related metabolic biomarkers derived from the gut microbiome. DESIGN: We recruited 358 patients with unruptured IA (UIA) and 161 with ruptured IA (RIA) from two distinct geographical regions for conducting an integrated analysis of plasma metabolomics and faecal metagenomics. Machine learning algorithms were employed to develop a classifier model, subsequently validated in an independent cohort. Mouse models of IA were established to verify the potential role of the specific metabolite identified. RESULTS: Distinct shifts in taxonomic and functional profiles of gut microbiota and their related metabolites were observed in different IA stages. Notably, tryptophan metabolites, particularly indoxyl sulfate (IS), were significantly higher in plasma of RIA. Meanwhile, upregulated tryptophanase expression and indole-producing microbiota were observed in gut microbiome of RIA. A model harnessing gut-microbiome-derived tryptophan metabolites demonstrated remarkable efficacy in distinguishing RIA from UIA patients in the validation cohort (AUC=0.97). Gut microbiota depletion by antibiotics decreased plasma IS concentration, reduced IA formation and rupture in mice, and downregulated matrix metalloproteinase-9 expression in aneurysmal walls with elastin degradation reduction. Supplement of IS reversed the effect of gut microbiota depletion. CONCLUSION: Our investigation highlights the potential of gut-microbiome-derived tryptophan metabolites as biomarkers for distinguishing RIA from UIA patients. The findings suggest a novel pathogenic role for gut-microbiome-derived IS in elastin degradation in the IA wall leading to the rupture of IA.

The Association Between Tumor Radiomic Analysis and Peritumor Habitat-Derived Radiomic Analysis on Gadoxetate Disodium-Enhanced MRI With Microvascular Invasion in Hepatocellular Carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) has a poor prognosis, often characterized by microvascular invasion (MVI). Radiomics and habitat imaging offer potential for preoperative MVI assessment. PURPOSE: To identify MVI in HCC by habitat imaging, tumor radiomic analysis, and peritumor habitat-derived radiomic analysis. STUDY TYPE: Retrospective. SUBJECTS: Three hundred eighteen patients (53 ± 11.42 years old; male = 276) with pathologically confirmed HCC (training:testing = 224:94). FIELD STRENGTH/SEQUENCE: 1.5 T, T2WI (spin echo), and precontrast and dynamic T1WI using three-dimensional gradient echo sequence. ASSESSMENT: Clinical model, habitat model, single sequence radiomic models, the peritumor habitat-derived radiomic model, and the combined models were constructed for evaluating MVI. Follow-up clinical data were obtained by a review of medical records or telephone interviews. STATISTICAL TESTS: Univariable and multivariable logistic regression, receiver operating characteristic (ROC) curve, calibration, decision curve, Delong test, K-M curves, log rank test. A P-value less than 0.05 (two sides) was considered to indicate statistical significance. RESULTS: Habitat imaging revealed a positive correlation between the number of subregions and MVI probability. The Radiomic-Pre model demonstrated AUCs of 0.815 (95% CI: 0.752-0.878) and 0.708 (95% CI: 0.599-0.817) for detecting MVI in the training and testing cohorts, respectively. Similarly, the AUCs for MVI detection using Radiomic-HBP were 0.790 (95% CI: 0.724-0.855) for the training cohort and 0.712 (95% CI: 0.604-0.820) for the test cohort. Combination models exhibited improved performance, with the Radiomics + Habitat + Dilation + Habitat 2 + Clinical Model (Model 7) achieving the higher AUC than Model 1-4 and 6 (0.825 vs. 0.688, 0.726, 0.785, 0.757, 0.804, P = 0.013, 0.048, 0.035, 0.041, 0.039, respectively) in the testing cohort. High-risk patients (cutoff value >0.11) identified by this model showed shorter recurrence-free survival. DATA CONCLUSION: The combined model including tumor size, habitat imaging, radiomic analysis exhibited the best performance in predicting MVI, while also assessing prognostic risk. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

Cerebrospinal fluid metabolomic and proteomic characterization of neurologic post-acute sequelae of SARS-CoV-2 infection.

The mechanism by which SARS-CoV-2 causes neurological post-acute sequelae of SARS-CoV-2 (neuro-PASC) remains unclear. Herein, we conducted proteomic and metabolomic analyses of cerebrospinal fluid (CSF) samples from 21 neuro-PASC patients, 45 healthy volunteers, and 26 inflammatory neurological diseases patients. Our data showed 69 differentially expressed metabolites and six differentially expressed proteins between neuro-PASC patients and healthy individuals. Elevated sphinganine and ST1A1, sphingolipid metabolism disorder, and attenuated inflammatory responses may contribute to the occurrence of neuro-PASC, whereas decreased levels of 7,8-dihydropterin and activation of steroid hormone biosynthesis may play a role in the repair process. Additionally, a biomarker cohort consisting of sphinganine, 7,8-dihydroneopterin, and ST1A1 was preliminarily demonstrated to have high value in diagnosing neuro-PASC. In summary, our study represents the first attempt to integrate the diagnostic benefits of CSF with the methodological advantages of multi-omics, thereby offering valuable insights into the pathogenesis of neuro-PASC and facilitating the work of neuroscientists in disclosing different neurological dimensions associated with COVID-19.

Strong Substance Exchange at Paddy Soil-Water Interface Promotes Nonphotochemical Formation of Reactive Oxygen Species in Overlying Water.

Photochemically generated reactive oxygen species (ROS) are widespread on the earth's surface under sunlight irradiation. However, the nonphotochemical ROS generation in surface water (e.g., paddy overlying water) has been largely neglected. This work elucidated the drivers of nonphotochemical ROS generation and its spatial distribution in undisturbed paddy overlying water, by combining ROS imaging technology with in situ ROS monitoring. It was found that H2O2 concentrations formed in three paddy overlying waters could reach 0.03-16.9 µM, and the ROS profiles exhibited spatial heterogeneity. The O2 planar-optode indicated that redox interfaces were not always generated at the soil-water interface but also possibly in the water layer, depending on the soil properties. The formed redox interface facilitated a rapid turnover of reducing and oxidizing substances, creating an ideal environment for the generation of ROS. Additionally, the electron-donating capacities of water at soil-water interfaces increased by 4.5-8.4 times compared to that of the top water layers. Importantly, field investigation results confirmed that sustainable •OH generation through nonphotochemical pathways constituted of a significant proportion of total daily production (>50%), suggesting a comparable or even greater role than photochemical ROS generation. In summary, the nonphotochemical ROS generation process reported in this study greatly enhances the understanding of natural ROS production processes in paddy soils.

lncTIMP3 promotes osteogenic differentiation of bone marrow mesenchymal stem cells via miR-214/Smad4 axis to relieve postmenopausal osteoporosis.

BACKGROUND: Promoting the balance between bone formation and bone resorption is the main therapeutic goal for postmenopausal osteoporosis (PMOP), and bone marrow mesenchymal stem cells (BMSCs) osteogenic differentiation plays an important regulatory role in this process. Recently, several long non-coding RNAs (lncRNAs) have been reported to play an important regulatory role in the occurrence and development of OP and participates in a variety of physiological and pathological processes. However, the role of lncRNA tissue inhibitor of metalloproteinases 3 (lncTIMP3) remains to be investigated. METHODS: The characteristics of BMSCs isolated from the PMOP rat model were verified by flow cytometry assay, alkaline phosphatase (ALP), alizarin red and Oil Red O staining assays. Micro-CT and HE staining assays were performed to examine histological changes of the vertebral trabeculae of the rats. RT-qPCR and western blotting assays were carried out to measure the RNA and protein expression levels. The subcellular location of lncTIMP3 was analyzed by FISH assay. The targeting relationships were verified by luciferase reporter assay and RNA pull-down assay. RESULTS: The trabecular spacing was increased in the PMOP rats, while ALP activity and the expression levels of Runx2, Col1a1 and Ocn were all markedly decreased. Among the RNA sequencing results of the clinical samples, lncTIMP3 was the most downregulated differentially expressed lncRNA, also its level was significantly reduced in the OVX rats. Knockdown of lncTIMP3 inhibited osteogenesis of BMSCs, whereas overexpression of lncTIMP3 exhibited the reverse results. Subsequently, lncTIMP3 was confirmed to be located in the cytoplasm of BMSCs, implying its potential as a competing endogenous RNA for miRNAs. Finally, the negative targeting correlations of miR-214 between lncTIMP3 and Smad4 were elucidated in vitro. CONCLUSION: lncTIMP3 may delay the progress of PMOP by promoting the activity of BMSC, the level of osteogenic differentiation marker gene and the formation of calcium nodules by acting on the miR-214/Smad4 axis. This finding may offer valuable insights into the possible management of PMOP.

Photoelectron Spectroscopy and Computational Study on Microsolvated [B10H10]2- Clusters and Comparisons to Their [B12H12]2- Analogues.

Microhydrated closo-boranes have attracted great interest due to their superchaotropic activity related to the well-known Hofmeister effect and important applications in biomedical and battery fields. In this work, we report a combined negative ion photoelectron spectroscopy and quantum chemical investigation on hydrated closo-decaborate clusters [B10H10]2-·nH2O (n = 1-7) with a direct comparison to their analogues [B12H12]2-·nH2O and free water clusters. A single H2O molecule is found to be sufficient to stabilize the intrinsically unstable [B10H10]2- dianion. The first two water molecules strongly interact with the solute forming B-H···H-O dihydrogen bonds while additional water molecules show substantially reduced binding energies. Unlike [B12H12]2-·nH2O possessing a highly structured water network with the attached H2O molecules arranged in a unified pattern by maximizing B-H···H-O dihydrogen bonding, distinct structural arrangements of the water clusters within [B10H10]2-·nH2O are achieved with the water cluster networks from trimer to heptamer resembling free water clusters. Such a distinct difference arises from the variations in size, symmetry, and charge distributions between these two dianions. The present finding again confirms the structural diversity of hydrogen-bonding networks in microhydrated closo-boranes and enriches our understanding of aqueous borate chemistry.

Cryogenic Photoelectron Spectroscopic and Theoretical Study of the Electronic and Geometric Structures of Undercoordinated Osmium Chloride Anions OsCln- (n = 3-5).

A series of anionic transition metal halides, OsCln- (n = 3-5), have been investigated using a newly developed, home-constructed, cryogenic anion cluster photoelectron spectroscopy. The target anionic species are generated through collision-induced dissociation in a two-stage ion funnel. The measured vertical detachment energies (VDEs) are 3.48, 4.54, and 4.81 eV for n = 3, 4, and 5, respectively. Density functional theory calculations at the B3LYP-D3(BJ)//aug-cc-pVTZ(-pp) level predict the lowest energy structures of the atomic form of OsCln- (n = 3-5) to be a quintet triangle, quartet square, and quintet square-based pyramid, respectively. The CCSD(T)-calculated VDEs and corresponding adiabatic detachment energies agree well with our experimental measurements. Analysis of the corresponding frontier molecular orbitals and charge density differences suggests that the d-orbitals of the transition metal Os play a primary role in the single-photon detachment processes, and the detached electrons originating from different molecular orbitals are distinguishable.

CircMYO1C silencing alleviates chondrocytes inflammation and apoptosis through m6A/HMGB1 axis in osteoarthritis.

Circular RNAs (circRNAs) are involved in osteoarthritis (OA) progression. This study aimed to investigate the role and molecular mechanisms of circMYO1C in OA. CircMYO1C was upregulated in OA- and interleukin-1ß (IL-1ß)-exposed chondrocytes. The results indicated that circMYO1C knockdown repressed the inflammatory factors (tumor necrosis factor alpha [TNF-α], interleukin-6 [IL-6], interleukin-8 [IL-8], etc.) and apoptosis of chondrocytes following IL-1ß exposure. CircMYO1C was an N6-methyladenosine (m6A)-modified circRNA with m6A characteristics. High mobility group box 1 (HMGB1) was a target of circMYO1C. IL-1ß exposure increased the stability and half-life (t1/2) of HMGB1 mRNA, while silencing circMYO1C reduced HMGB1 mRNA stability. Taken together, circMYO1C targets the m6A/HMGB1 axis to promote chondrocyte apoptosis and inflammation. The present study demonstrates that the circMYO1C/m6A/HMGB1 axis is essential for OA progression, highlighting a novel potential therapeutic target for clinical OA.

Deprotonated sulfamic acid and its homodimers: Does sulfamic acid adopt zwitterion during cluster growth?

We present a joint experimental and computational study on the geometric and electronic structures of deprotonated sulfamic acid (SA) clusters [(SA)n-H]- (n = 1, 2) employing negative ion photoelectron spectroscopy and high-level ab initio calculations. The photoelectron spectra provide the vertical/adiabatic detachment energy (VDE/ADE) of the sulfamate anion (SM-) H2N●SO3- at 4.85 ± 0.05 and 4.58 ± 0.08 eV, respectively, and the VDE and ADE of the SM-●SA dimer at 6.41 ± 0.05 and 5.87 ± 0.08 eV, respectively. The significantly increased electron binding energies of the dimer confirm the enhanced electronic stability upon the addition of one SA molecule. The CCSD(T)-predicted VDEs/ADEs agree excellently with the experimental data, confirming the identified structures as the most stable ones. Two types of dimer isomers possessing different hydrogen bonding (HB) motifs are identified, corresponding to SM- binding to a zwitterionic SA (SM-●SAz) and a canonical SA (SM-●SAc), respectively. Two N-H⋯O HBs and one superior O-H⋯O HB are formed in the lowest-lying SM-●SAc, while SM-●SAz has three moderate N-H⋯O HBs, with the former being 4.71 kcal/mol more stable. Further theoretical analyses reveal that the binding strength advantage of SM-●SAc over SM-●SAz arises from its significant contributions of orbital interactions between fragments, illustrating that sulfamate strongly interacts with its parent SA acid and preferably chooses the canonical SA in the subsequent cluster formations. Given the prominent presence of SA, this study provides the first evidence that the canonical dimer model of sulfamic acid should exist as a superior configuration during cluster growth.

Observation of a super-tetrahedral cluster of acetonitrile-solvated dodecaborate dianion via dihydrogen bonding.

We launched a combined negative ion photoelectron spectroscopy and multiscale theoretical investigation on the geometric and electronic structures of a series of acetonitrile-solvated dodecaborate clusters, i.e., B12H122-·nCH3CN (n = 1-4). The electron binding energies of B12H122-·nCH3CN are observed to increase with cluster size, suggesting their enhanced electronic stability. B3LYP-D3(BJ)/ma-def2-TZVP geometry optimizations indicate each acetonitrile molecule binds to B12H122- via a threefold dihydrogen bond (DHB) B3-H3 ⁝⁝⁝ H3C-CN unit, in which three adjacent nucleophilic H atoms in B12H122- interact with the three methyl hydrogens of acetonitrile. The structural evolution from n = 1 to 4 can be rationalized by the surface charge redistributions through the restrained electrostatic potential analysis. Notably, a super-tetrahedral cluster of B12H122- solvated by four acetonitrile molecules with 12 DHBs is observed. The post-Hartree-Fock domain-based local pair natural orbital- coupled cluster singles, doubles, and perturbative triples [DLPNO-CCSD(T)] calculated vertical detachment energies agree well with the experimental measurements, confirming the identified isomers as the most stable ones. Furthermore, the nature and strength of the intermolecular interactions between B12H122- and CH3CN are revealed by the quantum theory of atoms-in-molecules and the energy decomposition analysis. Ab initio molecular dynamics simulations are conducted at various temperatures to reveal the great kinetic and thermodynamic stabilities of the selected B12H122-·CH3CN cluster. The binding motif in B12H122-·CH3CN is largely retained for the whole halogenated series B12X122-·CH3CN (X = F-I). This study provides a molecular-level understanding of structural evolution for acetonitrile-solvated dodecaborate clusters and a fresh view by examining acetonitrile as a real hydrogen bond (HB) donor to form strong HB interactions.

Light-Responsive Supramolecular Liquid-Crystalline Metallacycle for Orthogonal Multimode Photopatterning.

The development of multimode photopatterning systems based on supramolecular coordination complexes (SCCs) is considerably attractive in supramolecular chemistry and materials science, because SCCs can serve as promising platforms for the incorporation of multiple functional building blocks. Herein, we report a light-responsive liquid-crystalline metallacycle that is constructed by coordination-driven self-assembly. By exploiting its fascinating liquid crystal features, bright emission properties, and facile photocyclization capability, a unique system with spatially-controlled fluorescence-resonance energy transfer (FRET) is built through the introduction of a photochromic spiropyran derivative, which led to the realization of the first example of a liquid-crystalline metallacycle for orthogonal photopatterning in three-modes, namely holography, fluorescence, and photochromism.

Unlocking the NIR-II AIEgen for High Brightness through Intramolecular Electrostatic Locking.

Fluorescent imaging and biosensing in the near-infrared-II (NIR-II) window holds great promise for non-invasive, radiation-free, and rapid-response clinical diagnosis. However, it's still challenging to develop bright NIR-II fluorophores. In this study, we report a new strategy to enhance the brightness of NIR-II aggregation-induced emission (AIE) fluorophores through intramolecular electrostatic locking. By introducing sulfur atoms into the side chains of the thiophene bridge in TSEH molecule, the molecular motion of the conjugated backbone can be locked through intramolecular interactions between the sulfur and nitrogen atoms. This leads to enhanced NIR-II fluorescent emission of TSEH in both solution and aggregation states. Notably, the encapsulated nanoparticles (NPs) of TSEH show enhanced brightness, which is 2.6-fold higher than TEH NPs with alkyl side chains. The in vivo experiments reveal the feasibility of TSEH NPs in vascular and tumor imaging with a high signal-to-background ratio and precise resection for tiny tumors. In addition, polystyrene nanospheres encapsulated with TSEH are utilized for antigen detection in lateral flow assays, showing a signal-to-noise ratio 1.9-fold higher than the TEH counterpart in detecting low-concentration antigens. This work highlights the potential for developing bright NIR-II fluorophores through intramolecular electrostatic locking and their potential applications in clinical diagnosis and biomedical research.

Rigid and Photostable Shortwave Infrared Dye Absorbing/Emitting beyond 1200 nm for High-Contrast Multiplexed Imaging.

The shortwave infrared (SWIR) spectral region beyond 1200 nm offers optimal tissue penetration depth and has broad potential in diagnosis, therapy, and surgery. Here, we devised a novel class of fluorochromic scaffold, i.e., a tetra-benzannulated xanthenoid (EC7). EC7 absorbs/emits maximally at 1204/1290 nm in CH2Cl2 and exhibits an unparalleled molar absorptivity of 3.91 × 105 cm-1 M-1 and high transparency to light at 400-900 nm. It also exhibited high resistance toward both photobleaching and symmetry breaking due to its unique structural rigidity. It is feasible for in vivo bioimaging and particularly suitable to couple with the shorter-wavelength analogues for high-contrast multiplexing. High-contrast dual-channel intraoperative imaging of the hepatobiliary system and three-channel in vivo imaging of the intestine, the stomach, and the vasculature were showcased. EC7 is a benchmark fluorochrome for facile biomedical exploitation of the SWIR region beyond 1200 nm.

STM2457 Inhibits the Invasion and Metastasis of Pancreatic Cancer by Down-Regulating BRAF-Activated Noncoding RNA N6-Methyladenosine Modification.

Pancreatic cancer is a malignant tumor of the digestive system that is highly malignant, difficult to treat, and confers a poor prognosis for patients. BRAF-activated noncoding RNA (BANCR) has been proven to play an important role in the invasion and metastasis of pancreatic cancer. In this study, we focused on BANCR as a potential therapeutic target for human pancreatic cancer. The BANCR level in pancreatic cancer tissues and cells is affected by m6A methylation. Based on this, the aim of our study was to investigate the effect of a highly potent and selective first-in-class catalytic inhibitor of METTL3 (STM2457) on BANCR m6A methylation and its malignant biological behaviors in pancreatic cancer. The relationship between BANCR expression and BANCR m6A modification was detected with RT-qPCR and MeRIP-PCR. The expression of methyltransferase-like 3 (METTL3), the key enzyme involved in m6A methylation, in pancreatic cancer tissues was detected using a Western blot. STM2457 was used in vitro to investigate its resistance to the proliferation, invasion, and metastasis of pancreatic cancer cells. BANCR was overexpressed in pancreatic cancer tissues and cells, which was associated with poor clinical outcomes and validated in pancreatic cancer cell lines. m6A modification was highly enriched within BANCR and enhanced its expression. Remarkably, STM2457 inhibited the proliferation, invasion, and metastasis of pancreatic cancer cells by down-regulating BANCR m6A modifications. This study demonstrates the promise of BANCR as a new diagnostic and therapeutic target for pancreatic cancer and reveals the therapeutic effect that STM2457 exerts on pancreatic cancer by down-regulating BANCR m6A modifications.

An MRI-Based Prognostic Stratification System for Medical Decision-Making of Multinodular Hepatocellular Carcinoma Patients Beyond the Milan Criteria.

BACKGROUND: The suitability of hepatectomy among patients with multinodular hepatocellular carcinoma (MHCC) beyond the Milan criteria remains controversial. There is a need for a reliable risk stratification tool among these patients for the selection of ideal candidates of curative resection. PURPOSE: To determine the clinicoradiological prognostic factors for patients with MHCC beyond the Milan criteria to further develop a stratification system. STUDY TYPE: Retrospective. SUBJECTS: 176 patients with pathologically confirmed MHCC beyond the Milan criteria. FIELD STRENGTH/SEQUENCE: The 1.5 T scanner, including T1-, T2-, diffusion-weighted imaging, in/out-phase imaging, and dynamic contrast-enhanced imaging. ASSESSMENT: Conventional MRI features and preoperative laboratory data including aspartate aminotransferase (AST) and α-fetoprotein (AFP) were collected and analyzed. Two nomograms incorporating clinicoradiological variables were independently constructed to predict recurrence-free survival (RFS) and overall survival (OS) with Cox regression analyses and verified with 5-fold cross validation. Based on the nomograms, two prognostic stratification systems for RFS and OS were further developed. STATISTICAL TESTS: The Cohen's kappa/intraclass correlation coefficient, C-index, calibration curve, Kaplan-Meier curve, log-rank test. A P value <0.05 was considered statistically significant. RESULTS: AST > 40 U/L, increased tumor burden score, radiological liver cirrhosis and nonsmooth tumor margin were independent predictors for poor RFS, while AST > 40 U/L, AFP > 400 ng/mL and radiological liver cirrhosis were independent predictors for poor OS. The two nomograms demonstrated good discrimination performance with C-index of 0.653 (95% confidence interval [CI], 0.602-0.794) and 0.685 (95% CI, 0.623-0.747) for RFS and OS, respectively. The 5-fold cross validation further validated the discrimination capability of the nomograms. Based on the nomogram models, MHCC patients beyond the Milan criteria were stratified into low-/medium-/high-risk groups with significantly different RFS and OS. DATA CONCLUSION: The proposed MRI-based prognostic stratification system facilitates the refinement and further subclassification of patients with MHCC beyond the Milan criteria. EVIDENCE LEVEL: 4. TECHNICAL EFFICACY: 2.

Untangling determinants of gut microbiota and tumor immunologic status through a multi-omics approach in colorectal cancer.

The changes in gut microbiota have been implicated in colorectal cancer (CRC). The interplays between the host and gut microbiota remain largely unclear, and few studies have investigated these interplays using integrative multi-omics data. In this study, large-scale multi-comic datasets, including microbiome, metabolome, bulk transcriptomics and single cell RNA sequencing of CRC patients, were analyzed individually and integrated through advanced bioinformatics methods. We further examined the clinical relevance of these findings in the mice recolonized with microbiota from human. We found that CRC patients had distinct microbiota compositions compared to healthy controls. A machine-learning model was developed with 28 biomarkers for detection of CRC, which had high accuracy and clinical applicability. We identified multiple significant correlations between genera and well-characterized genes, suggesting the potential role of gut microbiota in tumor immunity. Further analysis showed that specific metabolites worked as profound communicators between these genera and tumor immunity. Integrating microbiota and metabolome perspectives, we cataloged gut taxonomic and metabolomic features that represented the key multi-omics signature of CRC. Furthermore, gut microbiota transplanted from CRC patients compromised the response of CRC to immunotherapy. These phenotypes were strongly associated with the alterations in gut microbiota, immune cell infiltration as well as multiple metabolic pathways. The comprehensive interplays across multi-comic data of CRC might explain how gut microbiota influenced tumor immunity. Hence, we proposed that modifying the CRC microbiota using healthy donors might serve as a promising strategy to improve response to immunotherapy.

Engineered Salmonella inhibits GPX4 expression and induces ferroptosis to suppress glioma growth in vitro and in vivo.

PURPOSE: Glioma is a life-threatening malignancy where conventional therapies are ineffective. Bacterial cancer therapy has shown potential for glioma treatment, in particular, the facultative anaerobe Salmonella has been extensively studied. Meanwhile, ferroptosis is a newly characterized form of cell death. Nevertheless, the role of ferroptosis in Salmonella-induced tumour cell death remains unclear. Therefore, we aim to elucidate whether Salmonella YB1 exerts therapeutic effects via inducing ferroptosis in glioma. METHODS: Following Salmonella YB1 infection, mRNA sequencing was applied to detect ferroptosis-related gene expression and the levels of reactive oxygen species, malondialdehyde, and glutathione were quantified. Transmission electron microscopy (TEM) was then used to observe the changes in the mitochondrial morphology of glioma cells. The role of ferroptosis in the anti-tumor effect of YB1 was assessed in vivo in mouse tumor xenograft models. RESULTS: Whole-transcriptome analysis revealed that Salmonella YB1 infection alters ferroptosis-related gene expression in the U87 glioma cell line. Moreover, we found that Salmonella-induced ferroptosis is correlated with reduced levels of glutathione and glutathione peroxidase-4 (GPX4) and increased levels of reactive oxygen species and malondialdehyde in vitro. Meanwhile, TEM revealed that mitochondria are shrunken and mitochondrial membrane density increases in infected glioma cells. Experiments in vivo further showed that tumor growth in the Salmonella-treated group was significantly slower compared to the control and Fer-1 groups. However, Salmonella-induced tumor suppression can be reversed in vivo by Fer-1 treatment. CONCLUSION: Salmonella YB1 inhibits GPX4 expression and induces ferroptosis to suppress glioma growth. Hence, ferroptosis regulation might represent a promising strategy to improve the efficacy of bacterial cancer therapy.

Prognostic factors for long-term outcome in bifocal hepatocellular carcinoma after resection.

OBJECTIVES: This study aimed to evaluate whether the radiological similarity and clinicopathological factors determine the prognosis in bifocal hepatocellular carcinoma (bHCC) stratified by the Milan criteria. METHODS: Consecutive patients with pathologically confirmed bHCC examined between January 2016 and December 2018 were retrospectively enrolled and grouped based on the Milan criteria. Two radiologists independently evaluated whether the imaging features of both tumors were consistent or not, which was defined as the radiological similarity. The clinicopathological data were also collected. The multivariable Cox regression was applied to separately identify the independent factors for recurrence-free survival (RFS) and overall survival (OS) in bHCC within and beyond the Milan criteria. RESULTS: A total of 193 patients were evaluated and divided into the within the Milan criteria group (n = 72) and the beyond the Milan criteria group (n = 121). bHCC within the Milan criteria showed a significantly better prognosis than those beyond the criteria. In the within the Milan criteria group, HBV-DNA load >104 IU/mL, microvascular invasion (MVI), and different enhancement patterns were independently associated with poor RFS. MVI was an independent prognostic factor for poor OS. In the beyond the Milan criteria group, HBV infection, MVI, increased ratio of the larger to the smaller tumor diameter (RLSD) value, and low comprehensive similarity were associated with shorter RFS, whereas MVI and increased RLSD value were independent predictors for poor OS. CONCLUSIONS: Our study revealed that in addition to MVI- and HBV-related factors, similarity in imaging features between lesions of bHCC is associated with the long-term prognosis. KEY POINTS: • The prognosis of bifocal HCC patients within the Milan criteria is significantly better than those beyond the criteria. • The similarity in imaging features between lesions of bHCC was an independent prognostic factor. • The more similar the bifocal lesions are in imaging features, the better the prognosis is.