Biology subjects

Shen, J.

Publications and source records attributed to Shen, J..

At least 109 records · Page 6Linked to original sources

bioRxiv2024

Repression of PRMT activities sensitize homologous recombination-proficient ovarian and breast cancer cells to PARP inhibitor treatment

Therapeutic epigenetic modulation is currently being evaluated in the clinic to sensitize homologous recombination (HR)-proficient tumors to PARP inhibitors. To broaden its clinical applicability and identify more effective combination strategies, we conducted a drug screen combining PARP inhibitors with 74 well-characterized epigenetic modulators targeting five major classes of epigenetic enzymes. Notably, both type I PRMT inhibitors and PRMT5 inhibitors scored highly in combination efficacy and clinical prioritization. PRMT inhibition significantly enhanced PARP inhibitor-induced DNA damage in HR-proficient ovarian and breast cancer cells. Mechanistically, PRMT suppression downregulates DNA damage repair genes and BRCAness-associated pathways, while also modulating intrinsic innate immune responses within cancer cells. Integrative analysis of large-scale genomic and functional datasets from TCGA and DepMap further supports PRMT1, PRMT4, and PRMT5 as promising therapeutic targets in oncology. Importantly, dual inhibition of PRMT1 and PRMT5 synergistically sensitizes tumors to PARP inhibitors. Collectively, our findings provide strong rationale for the clinical development of PRMT and PARP inhibitor combinations in HR-proficient ovarian and breast cancers.

cancer biology↗

bioRxiv2024

The under-recognized dominance of magnetosome gene cluster-containing bacteria in oxygen-stratified freshwater ecosystems

Magnetotactic bacteria (MTB) capable of magnetosome organelle biomineralization and magnetotaxis are widespread in chemically stratified aquatic environments. Conventionally, it has long been considered that the overall abundance of MTB in microbiota is not very high and that Magnetococcia is the most frequently identified and predominant MTB members. However, the diversity and distribution of MTB in chemically stratified environments remain elusive due to the lack of large-scale systematic analyses. Here we conduct a comprehensive survey of genomes containing magnetosome gene clusters (MGCs), a group of genes responsible for magnetosome biomineralization and magnetotaxis, in 267 metagenomes from 38 oxygen-stratified freshwater environments. A total of 63 MGC-containing genomes belonging to eight bacterial phyla are reconstructed, including the newly identified Myxococcota. We discover an unexpectedly high relative abundance of putative MTB (up to 15.4% of metagenomic reads) in hypoxic and anoxic water columns, in which Deltaproteobacteria, rather than traditionally considered Magnetococcia, are the most ubiquitous and predominant MGC-containing bacteria. Our analysis reveals a depth-specific taxonomy and function of MGC-containing bacteria in stratified water columns shaped by physicochemical conditions. These findings underscore the unrecognized ecophysiological importance of MTB in freshwater ecosystems.

microbiology↗

bioRxiv2024

Multi-omic Analysis Identifies Glioblastoma Dependency on H3K9me3 Methyltransferase Activity

Histone H3 Lysine 9 dimethylation or trimethylation (H3K9me2 or H3K9me3) marks more than half of the human genome, particularly in heterochromatin regions and specific genes within euchromatic regions. Enzymes catalyzing the methylation of H3K9 have individually been associated with the modulation of gene expression patterns involved in cancer progression, including suppressor of variegation 3-9 homologue 1 (SUV39H1), SUV39H2, SET domain bifurcated 1 (SETDB1), SETDB2, euchromatic histone-lysine N-methyltransferase 1 and 2 (EHMT1/2). However, a comprehensive comparison and understanding of the characteristics and mechanisms of these chromatin-modifying enzymes in cancers remains incompletely understood. In this study, we demonstrated that these six H3K9 methyltransferases differentially expressed in tumors and correlated expression with somatic copy number variations (CNVs) and DNA methylation patterns. Through integrative multi-omics analyses, we identified SUV39H1, SUV39H2, and SETDB1 as the key players among the six H3K9 methyltransferases that exhibited the most significant associations with cancer phenotypes. By incorporating SUV39H1, SUV39H2, and SETDB1, we developed a novel signature termed "H3K9me3 MtSig" (H3K9me3 methyltransferases signature). H3K9me3 MtSig was unique for various tumor types, had prognostic implications and was linked to significant signaling pathways, particularly in glioblastoma (GBM). Furthermore, elevated H3K9me3 MtSig was confirmed in GBM patient-derived cells and tissues. In addition, single-cell expression analysis of H3K9me3 MtSig in GBM tissues demonstrated a pattern related to the G2/M cell cycle and was negatively correlated with immune responses. H3K9me3-mediated repetitive sequence silencing by H3K9me3 MtSig, determined using ChIP-sequencing, contributed to these phenotypes, and inhibiting H3K9me3 MtSig in patient-derived GBM cells suppressed proliferation and increased immune responses. Translationally, H3K9me3 MtSig performed as an independent prognostic factor in a clinical prediction model, and drug susceptibility screening integrating H3K9me3 MtSig identified potential biomarkers and therapeutics for GBM. In summary, H3K9me3 MtSig has the potential to elucidate novel prognostic markers, therapeutic targets, and predictors of treatment response in GBM and other cancer types for clinical intervention. SignificanceDifferential expressions of H3K9 methyltransferases across cancers correlates with clinical outcomes; in GBM, an H3K9me3 methyltransferase signature links to G2/M cell cycle, immune response pathways, and prognosis, aiding biomarker and treatment development.

cancer biology↗

bioRxiv2024

β-glucan induced trained immunity enhances antibody levels in a vaccination model in mice

Trained immunity improves disease resistance by strengthening our first line of defense, the innate immune system. Innate immune cells, predominantly macrophages, are epigenetically and metabolically rewired by {beta}-glucan, a fungal cell wall component, to induce trained immunity. These trained macrophages exhibit increased co-stimulatory marker expression and altered cytokine production. Signaling changes from antigen-presenting cells, including macrophages, polarize T-cell responses. Recent work has shown that trained immunity can generally enhance protection against infection, and some work has shown increased protection with specific vaccines. It has been hypothesized that the trained cells themselves potentially modulate adaptive immunity in the context of vaccines. However, the mechanistic link between trained immunity on subsequent vaccinations to enhance antibody levels has not yet been identified. We report that trained immunity induced by a single dose of {beta}-glucan increased antigen presentation in bone-marrow-derived macrophages (BMDMs) and CD4+ T cell proliferation in-vitro. Mice trained with a single dose of {beta}-glucan a week before vaccination elicited higher antigen-specific antibody levels than untrained mice. Further experiments validate that macrophages mediate this increase. This effect persisted even after vaccinations with 100 times less antigen in trained mice. We report {beta}-glucan training as a novel prophylactic method to enhance the effect of subsequent vaccines.

immunology↗

bioRxiv2024

Machine Learned Classification of Ligand Intrinsic Activities at Human μ-Opioid Receptor

Opioids are small-molecule agonists of {micro}-opioid receptor ({micro}OR), while reversal agents such as naloxone are antagonists of {micro}OR. Here we developed machine learning (ML) models to classify the intrinsic activities of ligands at the human {micro}OR based on the SMILE strings and two-dimensional molecular descriptors. We first manually curated a database of 983 small molecules with measured Emax values at the human {micro}OR. Analysis of the chemical space allowed identification of dominant scaffolds and structurally similar agonists and antagonists. Decision tree models and directed message passing neural networks (MPNNs) were then trained to classify agonistic and antagonistic ligands. The hold-out test AUCs (areas under the receiver operator curves) of the extra-tree (ET) and MPNN models are 91.5 {+/-} 3.9% and 91.8 {+/-} 4.4%, respectively. To overcome the challenge of small dataset, a student-teacher learning method called tri-training with disagreement was tested using an unlabeled dataset comprised of 15,816 ligands of human, mouse, or rat {micro}OR,{kappa} OR, or{delta} OR. We found that the tri-training scheme was able to increase the hold-out AUC of MPNN to as high as 95.7%. Our work demonstrates the feasibility of developing ML models to accurately predict the intrinsic activities of {micro}OR ligands, even with limited data. We envisage potential applications of these models in evaluating uncharacterized substances for public safety risks and discovering new therapeutic agents to counteract opioid overdoses. TOC Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/588485v2_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@1bf13f7org.highwire.dtl.DTLVardef@1b7f04aorg.highwire.dtl.DTLVardef@1009569org.highwire.dtl.DTLVardef@1515139_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2024

HNF&alpha is a target of the Wnt/beta-catenin pathway and regulates colorectal carcinogenesis

Hepatocyte nuclear factor 4alpha (HNF4) is a transcription factor involved in liver function. Dysregulation of HNF4 leads to hepatocarcinogenesis. However, the role and mechanism of HNF4 in colorectal cancer is still unknown. Here we demonstrate that HNF4 is upregulated in colorectal cancers. and HNF4 upregulation promotes colorectal tumorigenesis. Notably, expression levels of HNF4 are positively correlated with the Wnt/{beta}-catenin signaling pathway in colorectal cancer patients. Further, we showed that HNF4 is transcriptionally activated by Wnt/{beta}-catenin/TCF3 and is at least partially responsible for the oncognesis activity of the Wnt signaling in colorectal cancer. Our findings indicate that HNF4 is a direct target of that Wnt/{beta}-catenin pathway and could play an important role in colorectal carcinogenesis. Author SummaryHere we demonstrate that HNF4 is upregulated in colorectal cancers and HNF4 upregulation promotes colorectal tumorigenesis. Notably, expression level of HNF4 are positively correlated with the Wnt/{beta}-catenin pathway in colorectal cancer patients. Further, we showed that HNF4 is transcriptionally activated by Wnt/{beta}-catenin/TCF3 and is at least partially responsible for the oncognesis activity of the Wnt signaling pathway in colorectal cancer.

cancer biology↗

bioRxiv2024

Novel non-immunogenic trained immunity inducing small molecule with improved anti-tumor properties

Trained immunity refers to the non-specific innate immune memory response triggered by the epigenetic and metabolic rewiring of innate immune cells. A strengthened innate immune system significantly improves disease resistance. However, very few trained immunity-inducing molecules have been identified. Almost all molecules for training are primarily immunogenic and then subsequently induce training. Non-immunogenic molecules that induce training could be employed in therapies without the concern of adverse inflammatory reactions. We identified a small molecule, A1155463, that modulates cellular metabolism to induce trained immunity in macrophages in-vitro. We show that nanomolar concentrations of these compounds uniquely alter only cellular metabolism without leading to apoptosis. We further observed that these compounds could induce training in an in-vivo model in mice. A1155463 training improved anti-tumor resistance to B16.F10 melanoma cells. The effect was enhanced upon combination with checkpoint therapy. In summary, we report the discovery of a novel trained immunity-inducing small molecule with enhanced anti-tumor properties.

immunology↗

bioRxiv2024

Single-cell profiling reveals the intratumor heterogeneity and immunosuppressive microenvironment in cervical adenocarcinoma

BackgroundCervical adenocarcinoma (ADC) is more aggressive compared to other types of cervical cancer (CC), such as squamous cell carcinoma (SCC). The tumor immune microenvironment (TIME) and tumor heterogeneity are recognized as pivotal factors in cancer progression and therapy. However, the disparities in TIME and heterogeneity between ADC and SCC are poorly understood. MethodsWe performed single-cell RNA sequencing on 11 samples of ADC tumor tissues, with other 4 SCC samples served as controls. The immunochemistry and multiplexed immunofluorescence were conducted to validate our findings. ResultsCompared to SCC, ADC exhibited unique enrichments in several sub-clusters of epithelial cells with elevated stemness and hyper-malignant features, including the Epi_10_CYSTM1 cluster. ADC displayed a highly immunosuppressive environment characterized by the enrichment of regulatory T cells (Tregs) and tumor-promoting neutrophils. The Epi_10_CYSTM1 cluster recruits Tregs via ALCAM-CD6 signaling, while Tregs reciprocally induce stemness in the Epi_10_CYSTM1 cluster through TGF{beta} signaling. Importantly, our study revealed that the Epi_10_CYSTM1 cluster could serve as a valuable predictor of lymph node metastasis for CC patients. ConclusionsThis study highlights the significance of ADC-specific cell clusters in establishing a highly immunosuppressive microenvironment, ultimately contributing to the heightened aggressiveness and poorer prognosis of ADC compared to SCC.

cancer biology↗

bioRxiv2024

High-fidelity enhanced AsCas12a knock-in mice for efficient multiplexed gene editing, disease modeling and orthogonal immunogenetics

The advancement of CRISPR gene editing technology, especially the development of Cas9 knock-in mice, has significantly boosted the functional discovery of various genetics factors in diverse fields including genetics, genomics, immunology, and the biology of cancer. However, the pleiotropic effects on human disease and the complex nature of gene interaction networks require a knock-in mouse model capable of simultaneous multiplexed gene perturbation. Here, we present the generation and applications of Cre-dependent conditional and constitutive high-fidelity, enhanced AsCas12a (enAsCas12a-HF1) Rosa26-knock-in mice in the C57BL/6 background. With these mouse strains, we demonstrate highly efficient and multiplexed in vivo and ex vivo genome engineering as applied to lipid nanoparticle (LNP)-RNA-based liver protein targeting, AAV-based tumor modeling, and retrovirus-based immune cell engineering. By integrating with a dCas9-SPH CRISPR activation transgenic strain, we establish a simultaneous dual gene activation and knockout (DAKO) system that showcases the modular potential of these enAsCas12a-HF1 mice. Importantly, constitutive expression of enAsCas12a-HF1 does not lead to any discernable pathological differences as compared to the C57BL/6 background strain. These knock-in mice and the accompanying delivery methods would empower the deconvolution of complex gene interaction networks in broad areas of research.

bioengineering↗

bioRxiv2024

Why is the Omicron main protease of SARS-CoV-2 less stable than its wild-type counterpart? A crystallographic, biophysical, and theoretical study of the free enzyme and its complex with inhibitor 13b-K

During the continuing evolution of SARS-CoV-2, the Omicron variant of concern emerged in the second half of 2021 and has been dominant since November that year. Along with its sublineages, it has maintained a prominent role ever since. The Nsp5 main protease (Mpro) of the Omicron virus is characterized by a single dominant mutation, P132H. Here we determined the X-ray crystal structures of the P132H mutant (or O-Mpro) as free enzyme and in complex with the Mpro inhibitor, the alpha-ketoamide 13b-K, and we conducted enzymology, biophysical as well as theoretical studies to characterize the O-Mpro. We found that O-Mpro has a similar overall structure and binding with 13b-K; however, it displays lower enzymatic activity and lower thermal stability compared to the WT-Mpro (with "WT" referring to the original Wuhan-1 strain). Intriguingly, the imidazole ring of His132 and the carboxylate plane of Glu240 are in a stacked configuration in the X-ray structures determined here. The empirical folding free energy calculations suggest that the O-Mpro dimer is destabilized relative to the WT-Mpro due to the less favorable van der Waals interactions and backbone conformation in the individual protomers. The all-atom continuous constant pH molecular dynamics (MD) simulations reveal that His132 and Glu240 display coupled titration. At pH 7, His132 is predominantly neutral and in a stacked configuration with respect to Glu240 which is charged. In order to examine whether the Omicron mutation eases the emergence of further Mpro mutations, we also determined crystal structures of the relatively frequent P132H+T169S double mutant but found little evidence for a correlation between the two sites.

biochemistry↗

bioRxiv2024

Base-Assisted Mechanism of Acrylamide Reactions With Cysteines: QM/MM Simulations of Afatinib Reaction with EGFR

Acrylamides are the most commonly used warheads of targeted covalent inhibitors (TCIs) directed at cysteines; however, the reaction mechanisms of acrylamides in proteins remain controversial, particularly for those involving protonated or unreactive cysteines. Using the combined semiempirical quantum mechanics (QM)/molecular mechanics (MM) free energy simulations, we investigated the reaction between afatinib, the first TCI drug for cancer treatment, and Cys797 in the EGFR kinase. Afatinib contains a {beta}-dimethylaminomethyl ({beta}-DMAM) substitution which has been shown to enhance the intrinsic reactivity and potency against EGFR for related inhibitors. Two hypothesized reaction mechanisms were tested. Our data suggest that Cys797 becomes deprotonated in the presence of afatinib and the reaction proceeds via a classical Michael addition mechanism, with Asp800 stabilizing the ion-pair reactant state {beta}-DMAM+/C797- and the transition state of the nucleophilic attack. Our work elucidates an important structure-activity relationship of acrylamides in proteins.

biophysics↗

bioRxiv2024

YAP promotes chromosomal instability by transcriptionally activating AJUBA through its super enhancer in breast cancer

Chromosomal instability (CIN) has been proven to be a fundamental property of cancer and a key underlying mechanism of tumorigenesis and progression. Still, relatively few studies have revealed the mechanism of this process. In this research, we identified the core Hippo component, YAP, played a crucial role in CIN formation in breast cancer. Using public ChIP-seq data and bioinformatic analysis, we found YAP could transcriptionally induce spindle assembly checkpoint, AJUBA, via TEAD, then activate AJUBA-AURKA signaling. Abolish AJUBA-AURKA axis could reverse YAP-induced CIN formation and aberrant mitosis. Mechanically, YAP/TEAD complex could accumulate to the super enhancer region of AJUBA, thus significantly induced its expression, and subsequently promoted AURKA auto-phosphorylating. These findings revealed a novel cross-talk between Hippo and AJUBA-AURKA signaling, and provided a new insight in CIN formation in breast cancer.

cancer biology↗

bioRxiv2024

Screening for metastasis-related genes in mouse melanoma cells through sequential tail vein injection

Tumor metastasis, responsible for approximately 90% of cancer-associated mortality, remains poorly understood. Here in this study we employed a melanoma lung metastasis model to screen for metastasis-related genes. By sequential tail vein injection of mouse melanoma B16F10 cells and the subsequently derived cells from lung metastasis into BALB/c mice, we successfully obtained highly metastatic B16F15 cells after five rounds of in vivo screening. RNA-sequencing analysis of B16F15 and B16F10 cells revealed a number of differentially expressed genes, some of these genes have previously been associated with tumor metastasis while others are novel discoveries. The identification of these metastasis-related genes not only improve our understanding of the metastasis mechanisms, but also provide potential diagnostic biomarkers and therapeutic targets for metastatic melanoma.

cell biology↗

bioRxiv2024

The EGF/EGFR-YAP1/TEAD2 axis-mediated BRAF inhibitor vemurafenib resistance upregulates STIM1 in melanoma

STIM1 is the endoplasmic reticulum (ER) Ca2+ sensor for store-operated entry (SOCE) and closely correlated to carcinogenesis and tumor progression. Previously we found that STIM1 is upregulated in melanoma cells resistant to the BRAF inhibitor vemurafenib, but the regulation mechanism is unknown. Here, we show that vemurafenib resistance upregulates STIM1 through an EGF/EGFR-YAP1/TEAD2 axis. Vemurafenib resistance can lead to the increase of EGF and EGFR levels to activate the EGFR signaling pathway. Reactivated EGFR signal promotes YAP1 nuclear localization to increase the expression of STIM1. Our finding not only demonstrates the mechanism by which vemurafenib resistance promotes STIM1 expression, but also provides combined targeting EGF/EGFR-YAP1/TEAD2-STIM1 to improve the therapeutic efficiency of BRAF inhibitor in melanoma patients.

cancer biology↗

bioRxiv2023

Image-Based Assessment of Natural Killer Cell Activity against Glioblastoma Stem Cells

Glioblastoma (GBM) poses a significant challenge in oncology and stands as the most aggressive form of brain cancer. A primary contributor to its relentless nature is the stem-like cancer cells, called glioblastoma stem cells (GSCs). GSCs have the capacity for self-renewal and tumorigenesis, leading to frequent GBM recurrences and complicating treatment modalities. While natural killer (NK) cells exhibit potential in targeting and eliminating stem-like cancer cells, their efficacy within the GBM microenvironment is limited due to constrained infiltration and function. To address this limitation, novel investigations focusing on boosting NK cell activity against GSCs are imperative. This study presents two streamlined image-based assays assessing NK cell migration and cytotoxicity towards GSCs. It details protocols and explores the strengths and limitations of these methods. These assays could aid in identifying novel targets to enhance NK cell activity towards GSCs, facilitating the development of NK cell-based immunotherapy for improved GBM treatment.

cancer biology↗

bioRxiv2023

Mechanism of Dimer Selectivity and Binding Cooperativity of BRAF inhibitors

Aberrant signaling of BRAFV600E is a major cancer driver. Current FDA-approved RAF inhibitors selectively inhibit the monomeric BRAFV600E and suffer from tumor resistance. Recently, dimer-selective and equipotent RAF inhibitors have been developed; however, the mechanism of dimer selectivity is poorly understood. Here, we report extensive molecular dynamics (MD) simulations of the monomeric and dimeric BRAFV600E in the apo form or in complex with one or two dimer-selective (PHI1) or equipotent (LY3009120) inhibitor(s). The simulations uncovered the unprecedented details of the remarkable allostery in BRAFV600E dimerization and inhibitor binding. Specifically, dimerization retrains and shifts the C helix inward and increases the flexibility of the DFG motif; dimer compatibility is due to the promotion of the C-in conformation, which is stabilized by a hydrogen bond formation between the inhibitor and the C Glu501. A more stable hydrogen bond further restrains and shifts the C helix inward, which incurs a larger entropic penalty that disfavors monomer binding. This mechanism led us to propose an empirical way based on the co-crystal structure to assess the dimer selectivity of a BRAFV600E inhibitor. Simulations also revealed that the positive cooperativity of PHI1 is due to its ability to preorganize the C and DFG conformation in the opposite protomer, priming it for binding the second inhibitor. The atomically detailed view of the interplay between BRAF dimerization and inhibitor allostery as well as cooperativity has implications for understanding kinase signaling and contributes to the design of protomer selective RAF inhibitors.

biophysics↗

bioRxiv2023

Cdc13 exhibits dynamic DNA strand exchange in the presence of telomeric DNA

Telomerase is the enzyme that lengthens telomeres and is tightly regulated by a variety of means to maintain genome integrity. Several DNA helicases function at telomeres, and we previously found that the Saccharomyces cerevisiae helicases Hrq1 and Pif1 directly regulate telomerase. To extend these findings, we are investigating the interplay between helicases, single-stranded DNA (ssDNA) binding proteins (ssBPs), and telomerase. The yeast ssBPs Cdc13 and RPA differentially affect Hrq1 and Pif1 helicase activity, and experiments to measure helicase disruption of Cdc13/ssDNA complexes instead revealed that Cdc13 can exchange between substrates. Although other ssBPs display dynamic binding, this was unexpected with Cdc13 due to the reported in vitro stability of the Cdc13/telomeric ssDNA complex. We found that the DNA exchange by Cdc13 occurs rapidly at physiological temperatures, requires telomeric repeat sequence DNA, and is affected by ssDNA length. Cdc13 truncations revealed that the low-affinity binding site (OB1), which is distal from the high-affinity binding site (OB3), is required for this intermolecular dynamic DNA exchange (DDE). We hypothesize that DDE by Cdc13 is the basis for how Cdc13 "moves" at telomeres to alternate between modes where it regulates telomerase activity and assists in telomere replication.

biochemistry↗

bioRxiv2023

Senescent cells impair fracture repair through elevating ubiquitin-proteasome system activity in aged mice.

Senescent cells accumulate in multiple tissues with aging. Depletion of senescent cells benefits the aging related disease, such as aging bone fracture. However, the molecular mechanisms by which senescent cells regulate their neighboring bone cells are still not well-known. We reported that proteasome inhibitor enhanced fracture repair in aged mice. Senescent cells are major source of chronic inflammatory cytokines, which in turn induced protein ubiquitination. We reported that PDGFR{beta} was one of the highly ubiquitinated proteins in mesenchymal progenitors (MPCs) and TGF{beta} was the most increased SASP. In the current study, we found TGF{beta} induced PDGFR{beta} ubiquitination and proteasomal degradation through its E3 ligases. TGF{beta} neutralizing antibody blocked the inhibited callus derived MPC growth and increased Ub-PDGFR{beta} by senescent cells, which could be further prevented PDGFR{beta} inhibitor. These findings suggested senescent cells derived TGF{beta} impaired fracture repair in aged mice through elevating ubiquitination of PDGFR{beta}. The discovery of TGF{beta}-PDGFR{beta} pathway triggered by senescent cells opens avenues for optimizing treatment strategies for aging related disease by combination with the ligand of PDGFR{beta}.

cell biology↗