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Biology subjects

Sun, D.

Publications and source records attributed to Sun, D..

At least 37 records · Page 2Linked to original sources

How different AI models understand cells differently

AI single-cell foundation models (scFMs) are believed to be able to learn essential relations in cell transcriptomics with the attention modules in Transformer, but there is no method to reveal what they actually learned. We observed that different models may grasp different aspects of relations. To unravel the mystery, we propose scGeneLens, a framework for dissecting how scFMs perceive cells. We employed a sparse block attention to replace the original attention mechanism to concentrate attentions into a few dominant gene-gene relations, used attention propagation to trace how the relations propagate across Transformer layers, and used integrated gradients to disentangle the relative contributions of gene identity and expression in cell representations. We applied it to scFoundation and scGPT and show that they exhibit pluralistic perceptions of cells: scFoundation emphasizes relations among cell-type marker genes, resulting in stronger cell-type separability, whereas scGPT focuses more on genes involved in shared cellular pathways and core biological activities, leading to representations that generalize across conditions. The framework provides a unified lens for probing what scFMs learn about cells and offers actionable insights for the design of future cellular foundation models. Our code can be seen in https://anonymous.4open.science/r/scGeneLens-B771/.

bioinformatics↗

TMC5 promotes lung adenocarcinoma cell proliferation, migration and invasion by regulating epithelial-mesenchymal transition

Background/purposeIn recent years, evidence has indicated that transmembrane channel-like 5 (TMC5) plays an important role in various cancers. Previously, one study showed that TMC5 was highly expressed in lung adenocarcinoma (LUAD), but its mechanism in LUAD remained unclear. In this study, we aimed to investigate the effects of TMC5 and its underlying mechanisms in LUAD progression. MethodsThe expression level of TMC5 in LUAD tissues was detected by real-time quantitative PCR. TMC5 was knocked down in A549 and H1437 cell lines using lentiviral transfection. The oncogenic effect of TMC5 on LUAD cell proliferation was evaluated by CCK-8 assay and colony formation assay. Transwell assay was employed to assess migration and invasion. ResultsTMC5 was overexpressed in LUAD tissues compared with normal tissues. Suppression of TMC5 expression reduced proliferation, migration, and invasion, while also decreasing the expression of mesenchymal markers and increasing epithelial markers in A549 and H1437 cells. Conversely, higher TMC5 expression significantly increased the expression of mesenchymal markers and decreased epithelial markers. ConclusionTMC5 facilitates the malignant behaviors of LUAD cells by regulating epithelial-mesenchymal transition, suggesting its potential as a promising diagnostic and therapeutic target.

molecular biology↗

Unlocking karst biodiversity with eDNA: a validated qPCR toolkit for discovery and monitoring the worlds largest cavefish radiation (Cyprinidae: Sinocyclocheilus)

Environmental DNA (eDNA) enables non-invasive detection of aquatic species through trace genetic material, but uncertainties regarding DNA persistence, detection accuracy, and the limited taxonomic resolution of stygian fauna have constrained its use in subterranean aquatic environments. The species-rich cavefish genus Sinocyclocheilus, endemic to the karst landscapes of southwestern China, offers an excellent model for understanding these issues. With over eighty species, many of which are endemics, and many still being described, this lineage is taxonomically rich, poorly understood, and highly threatened. However, access to these deep habitats remains challenging, making eDNA detection one of the most practical methods for documenting and monitoring them. We developed and validated a qPCR assay targeting a hypervariable region of the mitochondrial 16S rRNA gene, allowing for genus-specific detection and species-level identification. Laboratory and field evaluations involving 47 representative species confirmed high specificity and a detection limit of around 20 DNA copies per reaction (R{superscript 2} = 0.995). Controlled degradation studies indicated that temperature and pH strongly affect DNA persistence. Field surveys across 47 karst sites (37 caves and 10 surface sites) detected Sinocyclocheilus eDNA in only 33 caves. Dideoxy sequencing of qPCR amplicons provided species-level identification and phylogenetic validation, including detection of a new species. At three cave sites yielding multiple qPCR detections, 16S metabarcoding enabled species discrimination. By integrating qPCR assay validation, eDNA degradation modelling, hierarchical genetic identification via dideoxy sequencing, and selective NGS metabarcoding, this study presents a strategic framework for applying eDNA methods in subterranean environments.

evolutionary biology↗

Effect of Perinatal Ampicillin or Amoxicillin/Clavulanate Exposure on Maternal and Infant Gut Microbiome, Metabolome, and Infant Responses to the 20-valent Pneumococcal Conjugate Vaccine

Emerging studies suggest that antibiotics can disrupt the gut microbiome and alter vaccine-induced immune responses, but the specific consequences of early-life exposure on neonatal immune development remains poorly understood. Here, we examined how two antibiotics frequently used in perinatal care, broad-spectrum ampicillin (AMP) and the extended-spectrum combination amoxicillin/clavulanate (AMOX/CLAV), administered during gestation and lactation, influence neonatal gut microbiome composition, fecal metabolome profiles, and responses to the 20-valent pneumococcal conjugate vaccine (PCV20). Maternal treatment with AMOX/CLAV, but not AMP, significantly reduced PCV-specific IgG titers at 4-and 6-weeks post-prime immunization compared to untreated controls. Exclusive exposure to AMOX/CLAV also impaired neutrophil-mediated opsonophagocytic killing, indicating diminished antibody functionality. These effects were transient, with immune parameters normalizing by week 8 post-prime immunization. Metabolomic and microbiome profiling revealed that maternal AMP and AMOX/CLAV differentially perturbed specific metabolite classes including bile acids, N-acyl lipids, and indole-derivatives, as well as key commensal taxa including Bacteroidales and Coriobacteriales within the gut microbiota. Together, these findings reveal a previously underappreciated maternal-offspring route of antibiotic influence that transiently disrupts neonatal vaccine responsiveness through microbiome and metabolome alterations. These results highlight maternal antibiotic exposure as a modifiable factor shaping early-life immunity.

microbiology↗

LARIS enables accurate and efficient ligand and receptor interaction analysis in spatial transcriptomics

Advances in spatially resolved transcriptomics provide unprecedented opportunities to characterise intercellular communication pathways. However, robust and computationally efficient incorporation of spatial information into intercellular communication inference remains challenging. Here, we present LARIS (Ligand And Receptor Interaction analysis in Spatial transcriptomics), an accurate and scalable method that identifies cell type-specific and spatially restricted ligand-receptor (LR) interactions at single-cell or bead resolution. LARIS is compatible with all spatial transcriptomic technologies and quantifies specificity, infers sender-receiver directionality, and detects how differential interactions vary across time and space. To compare LARIS with existing methods, we established a simulation framework to generate ground truth of LR interactions with defined tissue architecture and gene expression patterns. LARIS demonstrates superior performances over other methods in accuracy and scalability. We further applied LARIS to human tonsil and developing mouse cortex spatial transcriptomics datasets collected from various spatial techniques. This uncovered the signalling mechanisms shaping tissue organisation and their changes over time. LARIS reveals cell type-, niche-, and condition-specific signalling and scales to hundreds of thousands of cells in minutes. This provides an efficient and direct method for discovering the molecular interplay between apposed cells across development.

bioinformatics↗

Localized control of protein phase separation via membrane binding

Phase separation of protein-rich condensates is key for the spatial organization of cells. Multivalent proteins can phase separate in the bulk cytoplasm to form 3D condensates or at the membrane surface to form 2D condensates. How cells control 2D versus 3D phase transitions is not well understood. Here, we combine an in vitro model system of membrane surface phase separation with thermodynamic modelling to explore the relation of 2D and 3D phase transitions. We engineered the phase-separating protein FUS to bind to membranes and quantified 2D and 3D phase separation as a function of total FUS concentration and salt concentration. We find that membrane binding induces the formation of 2D surface condensates far below the bulk saturation concentration. In addition to direct FUS-membrane binding, surface condensates sequester more FUS molecules from the bulk via protein-protein interactions, resulting in a substantial deviation from the classical binding isotherm. By changing the protein-protein interaction strength via salt titration, we find that the saturation concentrations for 2D and 3D phase separation are coupled. By extending the classical theory of condensate wetting via membrane binding, we recapitulate the experimental results and show that tuning the membrane-binding strength of a phase-separating protein provides a robust way to control 2D condensation at the membrane over a wide concentration range without entering the 3D condensation regime. Taken together, our results provide a simple framework to understand how cells tune protein interactions and membrane binding to control 2D and 3D phase transitions.

biophysics↗

Simple Methods to Acutely Measure Multiple Timing Metrics among Sexual Repertoire of Male Drosophila

Male Drosophila courtship behavior is a key model for studying temporal decision-making. While courtship index (CI) is widely used to quantify mating activity, other timing metrics like courtship latency, copulation latency (CL), and mating duration (MD) remain understudied. Traditional methods for quantifying these behaviors are often labor-intensive and prone to human error. In this study, we present a protocol combining a modular chamber system and automated software (DrosoMating) to quantify 6 key timing metrics during male courtship. Our image-based video analysis enables precise identification of courtship and copulation events, as well as quantification of their timing and duration under controlled conditions. Validation shows <0.05% error rates and 98-99% agreement with manual scoring for CL, CI, and MD. The protocol supports genetic and neural circuit manipulations, detecting subtle genetic, social, and environmental behavioral variations. By minimizing manual effort and standardizing data collection, this approach facilitates scalable, reproducible studies on adaptive trade-offs, learning, and neural mechanisms in mating behavior. This method streamlines timing analysis in male courtship, offering reproducible metrics for behavioral genetics. HighlightA high-throughput software pipeline for automated temporal profiling of Drosophila melanogaster mating behavior after brief user-guided calibration. An accompanying, open-hardware platform that can be assembled at minimal cost while maintaining experimental rigor. The system attains near-manual accuracy and outputs Temporal Measurement Parameters data that are readily adaptable to--and quantifiable within--diverse behavioral paradigms.

developmental biology↗

Missense Mutation ADNP p.C687R Disrupts Chromatin Regulation and GABAergic Differentiation in HVDAS

Activity-dependent neuroprotective protein (ADNP) is a key regulator of neurodevelopment and a high-risk gene for autism spectrum disorder (ASD). Most pathogenic variants cause loss-of-function in Helsmoortel-Van der Aa syndrome (HVDAS), yet the impact of missense mutations remains unclear. Here, we characterized a ADNP missense mutation (p.C687R) identified from a HVDAS patient, predicted to disrupt its ninth zinc finger domain. Overexpression of p.C687R altered subnuclear localization and affected wild-type ADNP distribution. In utero electroporation revealed impaired neuronal migration and cortical branching. CUT&Tag profiling showed mutant- specific chromatin binding, preferentially targeting histone modification genes through both direct and distal interactions. Patient-derived iPSCs carrying p.C687R exhibited upregulated bivalent histone marks (H3K4me3 and H3K27me3) on neurodevelopmental genes, including regulators of GABAergic differentiation, which became transcriptionally activated in neural progenitors. These findings reveal a gain-of-function mechanism by which ADNP p.C687R perturbs chromatin regulation and disrupts GABAergic lineage specification, expanding the molecular framework of ADNP pathogenesis. The Paper Explained ProblemMutations in the gene ADNP cause Helsmoortel-Van der Aa syndrome (HVDAS), a severe neurodevelopmental disorder, and also increase the risk for autism spectrum disorder (ASD). While most known ADNP mutations lead to loss of protein function, many missense mutations that alter a single amino acid remain poorly understood regarding their effects on brain development and disease contribution. ResultsWe characterized a specific missense mutation, ADNP p.C687R, from a patient diagnosed with HVDAS, and found that it does not simply inactivate the protein but instead confers a disruptive new function. Across multiple models, from cells to mice, the p.C687R mutant exhibits abnormal chromatin binding, altered subnuclear localization, and impaired neuronal migration and differentiation. Importantly, in patient-derived iPSCs, it marks distinct neurodevelopmental genes with bivalent histone modifications, which become aberrantly activated during differentiation into GABAergic neural progenitor cells. ImpactThese findings confirm the pathogenicity of the missense mutation ADNP p.C687R in HVDAS, reveal a gain-of-function mechanism whereby the mutant disrupts chromatin regulation and GABAergic lineage specification, and advance our understanding of ADNP-related neurodevelopmental disorders.

neuroscience↗

Structural and functional insights into QueC-family protein in QatABCD anti-phage system

QatABCD is a widespread prokaryotic anti-phage defense system comprising four protein components, out of which QatC, a QueC-family protein is the signature component. QueC family proteins are nucleoside biosynthesis enzymes involved in the biosynthesis of queuosine, a 7-deazaguanine derivative. Recently, QueC-family proteins were shown to catalyze a deazaguanylation protein-nucleobase conjugation reaction in type IV CBASS antiphage defense. However, the mechanism of QatABCD, even the function of QatC in this system, remains unknown. Here, we demonstrate that QatBCD forms a complex in which QatD is highly flexible. Crystal structures of the QatBC complex in apo and ATP-bound form support a shared role for QueC-family proteins in targeting protein substrates for N-terminal modification as in type IV CBASS. We show that the QatB N-terminal loop, its binding with QatC and QatC catalytic site are essential for QatABCD defense in vivo, suggesting a modification might occur analogous to CBASS. These findings provide structural and functional insights into QueC-family protein in QatABCD system, suggesting the conserved mechanisms and critical roles of QueC-family in prokaryotic immunity.

biochemistry↗

Genome-wide CRISPR screen reveals Wnt signaling defects regulate lipid accumulation in APOE4 oligodendrocytes

APOE4 is the largest genetic risk factor for late-onset Alzheimers disease, but the cellular mechanisms by which APOE variants influence risk of disease remain incompletely understood. We have previously found that APOE4 expression led to the intracellular accumulation of lipid droplets in oligodendrocytes, causing decreased myelination. However, the mechanisms by which APOE4 alters lipid metabolism are not fully understood. Here, we leveraged a genome-wide CRISPR screen and ATAC-sequencing in human induced pluripotent stem cell (iPSC)-derived oligodendrocytes to dissect APOE4s lipid-associated mechanisms of action. Using these approaches, we identified decreased Wnt signaling, and overactive GSK3b activity, as regulators of lipid droplet accumulation in oligodendrocytes. Genetic and pharmacological inhibition of GSK3b reduced lipid droplets in APOE4 oligodendrocytes, and increased myelination in three-dimensional iPSC-derived brain organoids. Finally, we show that pharmacological inhibition of GSK3b reduces lipid droplets and improves myelination in APOE4;PS19 Tau transgenic mice. Together, our results provide a framework for understanding the mediation of APOE4-related changes to oligodendrocyte lipid metabolism and myelination.

neuroscience↗

Programming Microbe-Computer Interaction for Customized Life-Nonlife and Cross-Life Communication

This extension of human-computer interaction (HCI) paradigm to the non-intelligent microbe-computer interaction (MCI) is attractive for building generalized life-nonlife communication. Main challenges lie in how to construct biohybrid interface within individual MCI unit and thereafter program cross-life communication based on these MCI units. Here, we propose the design and construction of opto-interfaced MCI unit composed of engineered microbes and computer terminals, for enabling quantifiable transduction between microbial signals and digital signals. These units were able to serve as biohybrid sensors, actuators and transceivers, supporting biomonitoring, bio-actuation and microbe-centric bidirectional operations. Based on these functional units, we established programmable cross-life communication architectures capable of unicast, multicast, and logic-gate-driven communication with temporal dynamic control. The architectures were validated in biomedical scenarios including tumor hypoxia biomarking, epidermal heavy metal detoxification, and colitis intervention, demonstrating robust performance in closed-loop diagnostic-therapeutic applications. Additionally, we integrated MCI with an unmanned surface vessel for environmental monitoring, highlighting its cross-domain potential. Collectively, we provide a scalable strategy for building customized life-nonlife and cross-life communication, which is expected as an important complement to internet of things (IoT).

synthetic biology↗

Total variation of quantitative phase map reveals cellular Young's modulus

Collective cell migration is a fundamental physiological process involved in wound healing, development, and tissue regeneration. Though the role of the environmental stiffness in collective cell migration has been extensively investigated, the effects of cellular stiffness have been less studied due to the lack of high-throughput in situ methods for characterizing cellular stiffness. Here, we characterize the cellular Youngs modulus in situ with a large field of view and in real time using use quantitative phase microscopy. We found that standard deviation and total variation of the phase are inversely related to the cellular Youngs modulus, while the total variation of phase has finer mechanical resolution. Integrating the total variation of phase with cell segmentation algorithms, we efficiently analyzed the cellular Youngs modulus for cells in a monolayer. Using this system, we found the cells at the wound frontier are much softer than that of the cells in the inner region of monolayer in in vitro wound healing assay. At single cellular level, the Youngs modulus of leader cells, boundary cells, and inner cells are significantly distinct from each other. To conclude, our method would help elucidate the essential role of cellular stiffness in collective cell migration and has the potential to further benefit the progress of mechanobiology.

biophysics↗

Albumin-STING Nanocomplex Reprograms HSPCs to Antitumor Neutrophils with Enhanced MHC I Antigen Presentation for Cancer Immunotherapy

Tumor-associated immunosuppressive neutrophils, termed myeloid-derived suppressor cells (MDSCs), compromise cancer immunotherapy. They can be pathologically programmed as early the hematopoietic stem and progenitor cell (HSPC) stage by suppressing interferon signaling. Reprogramming HSPCs toward antitumor neutrophils through the stimulator of interferon genes (STING) activation offers a promising therapeutic strategy. Here, we demonstrate that an albumin-STING nanoagonist (Nano ZSA-51D) reprograms HSPCs to generate antitumor neutrophils, enhancing MHC I-mediated CD8 T cell immunity. Nano ZSA-51D activates STING-interferon signaling in HSPCs, promoting their expansion and differentiation toward granulocyte-monocyte progenitors via STING-NF-{kappa}B-IL-6 signaling. It further reprograms neutrophils into CD14ICAM-1+ subset through STING-NF-{kappa}B-TNF- signaling, enhancing tumor infiltration. These neutrophils upregulate interferon signaling and MHC I antigen presentation, boosting tumor-specific CD8 T cell responses. Adoptive transfer of Nano ZSA-51D-reprogrammed neutrophils with -PD1 therapy achieves complete colon tumor remission. Our findings provide a novel strategy to reprogram HSPCs toward antitumor neutrophils and highlight the potential of early interventions at HSPC stage to rewire neutrophil fate for cancer immunotherapy.

immunology↗

Resource: A Compendium of HLA-Type and Expression in Pediatric Cancer Models

Cancer immunotherapy has transformed cancer treatment by harnessing the immune systems natural ability to recognize and eliminate tumor cells, offering an effective and less toxic alternative particularly suitable for pediatric patients. Advances such as immune checkpoint inhibitors targeting PD-1 and CTLA-4, successful adoptive cell therapies like CAR T-cell treatments, and innovative cancer vaccines have notably improved outcomes across various cancer types. Central to immunotherapy is antigen presentation, where tumor-derived peptides loaded onto the Major Histocompatibility Complex molecules facilitate immune recognition. Precise HLA typing is crucial, especially in pediatric cancer research, where cell lines serve as essential preclinical models. The Childhood Cancer Model Atlas (CCMA) initiative provides comprehensive profiling, including HLA typing and neoantigen predictions for 287 cancer cell lines. This publicly accessible resource enables researchers to better understand immune-cancer interactions, advance personalized immunotherapies, and develop targeted, less toxic treatments specifically beneficial for children with cancer.

cancer biology↗

Volumetric Differences of Thalamic Nuclei are Associated with Post-Trauma Psychopathology

Previous investigations of whole thalamus and thalamic nuclei volumes in post-trauma psychopathology have been sparse, limited in scope, and yielded inconsistent results. To address this, volumetric estimates of whole thalamus and thalamic nuclei were obtained from structural brain MRI scans from 2,058 participants across 20 worldwide sites in the ENIGMA PTSD working group. Thalamic volumes were compared between trauma-exposed participants with posttraumatic stress disorder (PTSD) (n=238), major depressive disorder (MDD) (n=184), comorbid PTSD+MDD (n=618), and trauma-exposed control participants (n=1,018). PTSD and MDD symptom severity, PTSD symptom clusters, and childhood trauma were similarly examined for associations with thalamic volume. Participants with PTSD only compared to controls had smaller thalamic nuclei volumes in sensorimotor nuclei, including the parafascicular (Pf), ventral anterior magnocellular (VAmc), medial pulvinar (PuM), and anterior pulvinar (PuA) nuclei of the thalamus. MDD only and comorbid PTSD+MDD participants exhibited smaller mediodorsal thalamus volumes compared to controls. Overall PTSD and MDD symptom severity negatively correlated with the volume of the mediodorsal thalamus. A significant interaction between PTSD and MDD severity was found, such that MDD severity was positively associated with thalamic volume only among individuals with high PTSD severity. Avoidance and hyperarousal symptoms of PTSD were positively associated with thalamic volume, while re- experiencing and negative mood/cognition symptoms were negatively associated with thalamic volume. Childhood physical and emotional abuse were positively and negatively associated with thalamic volume, respectively. Whole thalamus volume and volumes of the sensorimotor and limbic thalamus may play an important role in the development of PTSD and MDD in the aftermath of trauma exposure. The interaction between PTSD and MDD symptoms and contrasting effects across PTSD symptom clusters and types of childhood adversity suggests multiple neurobiological mechanisms are involved in shaping thalamic volume post-trauma.

neuroscience↗

Endogenous gene editing of alveolar organoids reveals that expression of pathogenic variant SFTPC-I73T disrupts endosomal function, epithelial polarity and wound healing

BackgroundIdiopathic pulmonary fibrosis is a fatal lung disease of progressive lung parenchymal scarring caused by the aberrant response of an alveolar epithelium repeatedly exposed to injury. Understanding epithelial dysfunction has been hampered by the lack of physiological alveolar type 2 (AT2) cell models and defined disease triggers. Monogenic forms of familial pulmonary fibrosis (FPF) caused by toxic gain-of-function variants provide an opportunity to investigate early pathogenic events. One such variant, surfactant protein C (SFTPC)-I73T, abnormally localises within AT2 cells and causes their dysfunction. MethodsWe used base editing of fetal lung-derived AT2 (fdAT2) organoids to create a heterozygous disease model of endogenous SFTPC-I73T expression. We also created an inducible overexpression system to interrogate temporal changes associated with SFTPC-I73T expression. We cultured fdAT2 both in 3D culture and at air-liquid interface to understand the importance of polarity cues and air exposure on disease phenotypes. ResultsIn our heterozygous endogenous expression system, we found that fdAT2 expressing SFTPC-I73T grew without a lumen and were unable to correctly polarise. SFTPC-I73T accumulated with time and caused gross enlargement of early endosomes, preventing correct apico-basal trafficking of multiple endosomally trafficked cargoes including polarity markers and cell adhesion proteins. This phenotype was exacerbated by air exposure and led to loss of epithelial monolayer integrity and abnormal wound healing after injury. ConclusionUsing endogenous gene editing for the first time in differentiated alveolar organoids, we have demonstrated that the pathogenic effects of SFTPC-I73T are mediated through endosomal dysfunction and abnormal epithelial organisation. This has important implications for AT2 function in vivo.

cell biology↗

Macropinocytosis inhibition attenuates pro-fibrotic responses in lung fibroblasts and pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a devastating chronic lung disorder with limited treatment options. Macropinocytosis is one of the key cellular processes involved in nutrient consumption from the extracellular environment under stress conditions. Here, we studied the role of macropinocytosis in lung fibroblast activation and experimental pulmonary fibrosis. We found that macropinocytosis is increased in human lung fibroblasts (HLFs) derived from IPF patients. The inhibition of macropinocytosis with 5-(n-ethyl-n-isopropyl)-amiloride (EIPA) significantly inhibited profibrotic responses in IPF-derived and TGF-{beta}1-stimulated HLFs. EIPA exerted antifibrotic effects by regulating amino acid (AA) uptake, mammalian target of rapamycin complex 1 (mTORC1) activation and mesenchyme homeobox1 (MEOX1) expression in activated HLFs. Both genetic and pharmacological inhibition of macropinocytosis significantly ameliorated pulmonary fibrosis in bleomycin (Bleo)-injured mice. Using IPF-derived precision cut lung slices (PCLS), we observed robust repression of profibrotic gene expression programs in EIPA-treated PCLS across different fibroblast subpopulations. Finally, we found that imipramine (Imi), a tricyclic antidepressant approved by the Food and Drug Administration (FDA), effectively inhibited macropinocytosis and ameliorated profibrotic responses in lung fibroblasts, Bleo-injured mice and IPF-derived PCLS. Taken together, our results suggest macropinocytosis inhibition as a potential therapeutic strategy to treat pulmonary fibrosis.

molecular biology↗

CRISPR-Based Gene Dependency Screens reveal Mechanism of BRAF Inhibitor Resistance in Anaplastic Thyroid Cancer

Anaplastic thyroid cancer (ATC) is the most aggressive form of thyroid cancer. Despite recent advances in treating BRAFV600E-driven ATC, therapy resistance remains a significant challenge, often resulting in disease progression and death. Leveraging a focused CRISPR/KO screen in parallel with a CRISPR/activation screen, both tailored on response to BRAFV600E inhibitor treatment, we identified TAZ (encoded by the WWTR1 gene) deficiency as synthetically lethal with BRAF inhibitor in ATC. TAZ is overexpressed in ATC compared to well-differentiated thyroid tumors. We demonstrate that TAZ-deficient ATC cells display heightened sensitivity to BRAF inhibitors both in vitro and in vivo. Using gene essentiality score across a large panel of cancer cell lines, we found that BRAFV600E-driven cancers are highly sensitive to TAZ loss, unlike their counterparts with wild-type BRAF and non-BRAFV600E. Mechanistically, we demonstrate that dabrafenib triggers the Unfolded Protein Response (UPR) under ER stress and suppresses protein synthesis. TAZ loss represses the UPR, reverses the inhibition of protein synthesis, and triggers increased cell death by ferroptosis in dabrafenib-treated ATC. Collectively, our findings unveil TAZ as a new target to overcome resistance to BRAF inhibitors in undifferentiated thyroid cancer.

cancer biology↗