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Results for “Cancer Biology”

Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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Novel Strategy against AML by Rescuing Loss of Phase Separation of Pathogenic NPM1c

Nucleophosmin (NPM1) is a nucleolar protein that participates in many biological processes through phase separation. In acute myeloid leukemia (AML), nearly one-third of cases harbor NPM1c mutations. Previous studies mainly focused on the contribution of the additional NES in NPM1c mislocalization and AML development; however, the mechanisms underlying the relationship between aberrant localization and phase separation of NPM1c remain poorly understood. In this study, we demonstrate that loss of phase separation (LoPS) with RNA is associated with NPM1c mislocalization, which uncovers a new strategy for therapeutic targeting of NPM1c. Leveraging high-throughput screening, we identify a potent small molecule capable of rescuing NPM1c LoPS in vitro and effectively restoring the nucleolar localization of NPM1c within cells. Remarkably, this compound demonstrates anti-leukemia activity in both AML cell lines and patient-derived blasts. Overall, these findings indicate a promising avenue for developing new AML therapies against NPM1c by reinstating its phase separation capabilities. One-Sentence SummaryRescuing the lost phase separation capacity of NPM1c unveils a promising AML therapy.

cancer biology↗

Targeted Degradation of CDK9 Potently Disrupts the MYC Transcriptional Network

Cyclin-dependent kinase 9 (CDK9) coordinates signaling events that regulate RNA polymerase II (Pol II) pause-release states. It is an important co-factor for transcription factors, such as MYC, that drive aberrant cell proliferation when their expression is deregulated. CDK9 modulation offers an approach for attenuating dysregulation in such transcriptional programs. As a result, numerous drug development campaigns to inhibit CDK9 kinase activity have been pursued. More recently, targeted degradation has emerged as an attractive approach. However, comprehensive evaluation of degradation versus inhibition is still critically needed to assess the biological contexts in which degradation might offer superior therapeutic benefits. We validated that CDK9 inhibition triggers a compensatory mechanism that dampens its effect on MYC expression and found that this feedback mechanism was absent when the kinase is degraded. Importantly, CDK9 degradation is more effective than its inhibition for disrupting MYC transcriptional regulatory circuitry likely through the abrogation of both enzymatic and scaffolding functions of CDK9. Highlights- KI-CDK9d-32 is a highly potent and selective CDK9 degrader. - KI-CDK9d-32 leads to rapid downregulation of MYC protein and mRNA transcripts levels. - KI-CDK9d-32 represses canonical MYC pathways and leads to a destabilization of nucleolar homeostasis. - Multidrug resistance ABCB1 gene emerged as the strongest resistance marker for the CDK9 PROTAC degrader.

cancer biology↗

A Self-Assembling Immune-Featured Osteosarcoma Patient/PDX Derived Organoid Model and Biobank for Personalized Immune Therapy

Osteosarcoma (OS) exhibit intra- and inter-heterogeneity, complicating the exploration of effective therapeutic strategies. Traditional in vitro and in vivo models are limited in inheriting biological and genomic heterogeneities of OS patients, even in inheriting the features on tumor microenvironment. The prolonged generation time of current models makes the drug development of OS slow and is not suitable to clinically rapid timing. Here, we introduce methods for generating and biobanking patient/PDX-derived osteosarcoma organoids (OS PD(X)Os) that recapitulate the histological, biological and genomic features of their paired OS patients. OS PD(X)Os can be generated quickly with high reliability in vitro or transplanted to immunodeficient mice. We further demonstrate an immune-featured OS PD(X)O (named iOS) model and its method for testing personalized chemotherapy response, personalized immune therapeutic strategy and target drug development, such as a novel PRMT5MTA inhibitor ARPN2169 on MTAP-deleted OS. Our studies show that iOS models maintain many typical features of OS and could be rapidly employed to investigate patient-specific therapeutic strategies. Additionally, our biobank establishes a rich resource for basic, translational and even clinical OS researches.

cancer biology↗

Heat Shock Factor 1 (HSF1) specifically potentiates c-MYC-mediated transcription independently of the canonical heat-shock response

Despite its pivotal roles in biology, how the transcriptional activity of c-MYC is attuned quantitatively remain poorly defined. Here, we show that heat shock factor 1 (HSF1), the master transcriptional regulator of the heat-shock, or proteotoxic stress, response, acts as a key modifier of the c-MYC-mediated transcription. HSF1 deficiency diminishes c-MYC DNA binding and dampens its transcriptional activity genome-widely. Mechanistically, c-MYC, MAX, and HSF1 assemble into a transcription factor complex on genomic DNAs and, surprisingly, the DNA binding of HSF1 is dispensable. Instead, HSF1 physically recruits the histone acetyltransferase GCN5, thereby promoting histone acetylation and augmenting c-MYC transcriptional activity. Thus, our studies reveal that HSF1 specifically potentiates the c-MYC-mediated transcription, distinct from its role in the canonical heat-shock response. Importantly, this mechanism of action engenders two distinct c-MYC activation states, primary and advanced, which may be important to accommodate diverse physiological and pathological conditions.

cancer biology↗

Modeling of Aryl Hydrocarbon Receptor Pathway Intrinsic Immunometabolic Role using Glioblastoma Stem Cells and Patient-Derived Organoids

The intrinsic genetic program of glioblastoma (GBM) stem cells is critical for tumor evolution and recurrence. We recently identified intrinsic phenotypes and immune-like genetic programs of GBM organoids (GBMO)1 from patient derived glioblastoma stem cells (GSCs), replicating genomic, metabolic, and cellular aspects of GBM in vivo. Aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, is a key regulator of infiltrating immune cells in gliomas2, 3 and associated with poor prognosis, but its role in GSC biology is unknown2. Here, we show that AHR is a patient-specific regulator of the glioma intrinsic gene program in GSCs and GSC-derived GBMO that are enriched for AHR. We find that AHR is required for GSC self-renewal, GBMO expansion, radial glia-like cell proliferation, and expression of immune mediators seen in the mesenchymal subtype. CRISPR-Cas9 genetic ablation and pharmacological inhibition revealed that AHR regulates genes linked to intrinsic immunity, proliferation, and migration in GBMO. Genomic analysis of GBMO treated with AHR inhibitors identified expression signatures and candidate markers associated with survival of gliomas. Our work defines the glioma intrinsic function of AHR in a model of early GBM formation, offering a rationale for clinical exploration of a potential two-hit target of both GBM cells and infiltrating immune cells in patients with GBM expressing high levels of AHR.

cancer biology↗

Engineered model of t(7;12)(q36;p13) AML recapitulates patient-specific features and gene expression profiles

Acute myeloid leukaemia carrying the translocation t(7;12)(q36;p13) is an adverse-risk leukaemia uniquely observed in infants. Despite constituting up to 30% of cases in under 2-year-olds, it remains poorly understood. Known molecular features are ectopic overexpression of the MNX1 gene and generation of a fusion transcript in 50% of patients. Lack of research models has hindered understanding of t(7;12) biology, which has historically focused on MNX1 overexpression rather than the cytogenetic entity itself. Here, we employed CRISPR/Cas9 to generate t(7;12) in the human K562 cell line, and in healthy CD34+ haematopoietic progenitors where the translocation was not sustained in long-term cultures or through serial replating. In contrast, in K562 cells, t(7;12) was propagated in self-renewing clonogenic assays, with sustained myeloid bias in colony formation and baseline depletion of erythroid signatures. Nuclear localisation analysis revealed repositioning of the translocated MNX1 locus to the interior of t(7;12)-harbouring K562 nuclei - a known phenomenon in t(7;12) patients which associates with ectopic overexpression of MNX1. Crucially, the K562-t(7;12) model successfully recapitulated the transcriptional landscape of t(7;12) patient leukaemia. In summary, we engineered a clinically-relevant model of t(7;12) acute myeloid leukaemia with the potential to unravel targetable molecular mechanisms of disease.

cancer biology↗

Spatial organization of the mouse chromosomes influences the landscape of intrachromosomal exchange aberration breakpoints

How 3D chromosome organization affects chromosomal aberrations is an important unresolved question in cell and radiation biology. In interphase the chromosomes form territories where chromatin folds into quite heterogeneous states. The mechanisms determining the spectrum of chromosome conformations remain poorly understood. We introduced the polymer model of mouse chromosome and generated the ensemble of 3D conformations. The chromosome model was validated against independent Hi-C (high-throughput chromosome conformation capture) data. The model described well Hi-C contact heatmap for chromosome 18 in pro-B mouse cells, both ATM-deficient and wild-type. We used the chromosome model to assess the role of chromosome structure in breakpoint distribution for intrachromosomal exchange aberrations. We investigated the effect of elevated frequency of breakpoints outside of the region of enzymatic breaksite. Chromosome aberration model explained breakpoint distribution under recurrent and ionizing radiation-induced DNA double-strand breaks in mouse chromosome 18 on the basis of contact-first mechanism. Overall, our results provide a framework for assessment of role of chromosome 3D organization on chromosome aberrations following DNA damage of different origin.

cancer biology↗

Selective loss of Y chromosomes in lung adenocarcinoma modulates the tumor immune environment through cancer/testis antigens

There is increasing recognition that the allosomes, X and Y, play an important role in health and disease beyond the determination of biological sex. A loss of the Y chromosome (LOY) occurs in most solid tumors in males and is often associated with worse survival, suggesting that LOY may give tumor cells a growth or survival advantage. We here use an expression-based continuous measure of LOY that allows us to investigate LOY in lung adenocarcinoma (LUAD) using both bulk and single-cell expression data. We find evidence suggesting that LOY affects the tumor immune environment by altering cancer/testis antigen expression and consequently facilitating tumor immune evasion, also reflected in inferred gene regulatory networks. In immunotherapy data, we further show that LOY and changes in expression of particular cancer/testis antigens are associated with response to pembrolizumab treatment and outcome. This computational study provides new insights into the mechanisms behind LOY in LUAD and a powerful biomarker for predicting immunotherapy response in LUAD tumors in males.

cancer biology↗

Beyond Conventional Models: Recreating the Initiation, Evolution, and Genome of GBM

BackgroundImagining ways to prevent or treat glioblastoma (GBM) have been hindered by a lack of understanding of its pathogenesis. Although PDGF-AA overexpression may be an early event, critical details of the core biology are lacking. Existing PDGF-driven models replicate its microscopic appearance but not the genomic architecture characteristic of the human disease. Here we report a new model of GBM that overcomes this barrier to authenticity. MethodsUsing a method developed to study neural stem cells, we investigated the effects of PDGF-AA on subventricular zone (SVZ) cells, the putative cell of origin of GBM. We micro-dissected SVZ tissue from p53-null and wild-type adult mice, established primary cultures in media supplemented with PDGF-AA, and assessed cell viability, proliferation, genome stability, and tumour forming potential. ResultsCounterintuitive to its canonical role as a growth factor, we observed immediate and massive death of SVZ cells in PDGF-AA. Wild-type cells did not survive in PDGF-AA. However, a small fraction of null cells evaded apoptosis, displayed attenuated proliferation, gradually accumulated whole chromosome gains and losses, and, signalled by sudden rapid proliferation and growth factor independence, became tumorigenic in immune-competent syngeneic mice. Transformed cells had an OPC-like profile, were resistant to PDGFR- inhibition, and harboured highly abnormal karyotypes similar to those seen in human GBMs. ConclusionThis model associates genome instability in SVZ cells with chronic exposure to PDGF-AA; it is the first model to replicate the genomic landscape of GBM and first in which the earliest phases of GBM can be directly observed. IMPORTANCE OF STUDYWe have developed a mouse model in which the initiation, evolution and genomic landscape of GBM can be thoroughly studied thus paving the way for ideas about how this deadly brain cancer might be prevented, interrupted at an occult stage, or treated with very different therapies.

cancer biology↗

Single Nuclei-Derived Molecular Subtypes of Gastrointestinal Stromal Tumors Correlate with Clinicopathologic Features and Predict Clinical Outcomes

Historically, gastrointestinal stromal tumor (GIST) has been subtyped by oncogenic driver mutations. However, tumors with the same mutational profile can have variable biology. To further explore the impact of molecular diversity on GIST biology, we performed single nucleus RNA sequencing on 16 primary GIST and utilized an integrated single cell atlas of the normal GI tract composed from multiple publicly available datasets to identify six distinct GIST cell states. We then statistically estimated the relative abundances of these profiles in bulk transcriptomic data. These were used to define six common GIST molecular subtypes based upon one or two predominant tumor cell states. We found that these molecular subtypes correlate with tumor locations, mutational profiles, and patient outcomes, and validated these subtypes in an independent international cohort. These molecular subtypes have the potential to be used for clinical prognostication for patients with GIST, identifying new therapeutic targets, and studying the cell of transformation of GIST.

cancer biology↗

IOBR2: Multidimensional Decoding Tumor Microenvironment for Immuno-Oncology Research

The use of large transcriptome datasets has greatly improved our understanding of the tumor microenvironment (TME) and helped develop precise immunotherapies. The increasing popularity of multi-omics sequencing, single-cell transcriptome sequencing (scRNA), and spatial transcriptome sequencing has led to numerous new discoveries. However, these findings require clinical phenotypic validation with a large sample size. To enhance the integration of multi-omics in advancing research on the tumor microenvironment, we have developed a systematic and comprehensive analytical tool (Immuno-Oncology Biological Research 2, IOBR2) based on our prior work. IOBR2 offers six modules for TME analysis based on multi-omics data. These modules cover data preprocessing, TME estimation, TME infiltrating patterns, cellular interactions, genome and TME interaction, and visualization for TME relevant features, as well as modelling based on key features. IOBR2 integrates multiple vital microenvironmental analysis algorithms and signature estimation methods, simplifying the analysis and downstream visualization of the TME. In addition to providing a quick and easy way to construct gene signatures from single-cell data, IOBR2 also provides a way to construct a reference matrix for TME deconvolution from single-cell RNAseq. The analysis pipeline and feature visualization are user-friendly and provide a comprehensive description of the complex TME, offering insights into tumor-immune interactions. A comprehensive gitbook (https://iobr.github.io/book/) is available with a user-friendly manual and complete analysis workflow for each module.

cancer biology↗

ASS1 deficiency defines a therapeutic vulnerability in Philadelphia chromosome-positive acute lymphoblastic leukaemia

Amino acid deprivation with L-asparaginase is a cornerstone of treatment in acute lymphoblastic leukaemia (ALL), but clinical challenges limit its use in adults. Deficiency in the enzyme argininosuccinate synthase (ASS1-low) confers arginine auxotrophy, defining a dependence on extracellular arginine, and represents an analogue metabolic vulnerability that is targetable through arginine deprivation. We analysed transcriptomic data across >550 adult B-ALL cases to establish clinico-biologic characteristics of low ASS1 expression identifying the Philadelphia chromosome-positive (Ph+) ALL subgroup as a stereotypical arginine auxotroph within molecularly diverse B-ALL. Functionally, arginine deprivation with pegargiminase induced robust apoptosis in both Ph+ ALL cell lines and primary samples in an ASS1-dependant manner and was highly effective as a monotherapy treatment in independent Ph+ ALL patient derived xenografts. Mechanistically, arginine deprivation induces endoplasmic reticulum stress mediated apoptosis which was orthogonal to tyrosine kinase inhibition (TKI) mediated outcomes. Using in vitro and in vivo models of non-genetically mediated TKI-resistance, we demonstrate pegargiminase and TKI combinations robustly eradicates TKI-resistant leukaemia. Thus, we establish ASS1 deficiency (ASS1-low) as a therapeutically actionable vulnerability in Ph+ ALL and a strategy to bypass TKI-resistance, supporting clinical evaluation of arginine deprivation as a novel adjunct to chemotherapy-free treatment.

cancer biology↗

DNFE: Directed-network flow entropy for detecting the tipping points during biological processes

There generally exists a critical state or tipping point from a stable state to another in dynamic biological processes, beyond which a significant qualitative transition occurs. Identifying this tipping point and its driving network is essential to prevent or delay catastrophic consequences. However, most traditional approaches based on undirected networks still suffer from the problem of the robustness and effectiveness when applied to high-dimensional small sample data, especially for single-cell data. To address this challenge, we developed a directed-network flow entropy (DNFE) method which can transform measured omics data into a directed network. This method is applicable to both single-cell RNA-sequencing (scRNA-seq) and bulk data. By applying this method to five real datasets, including three single-cell datasets and two bulk tumor datasets, the method can not only successfully detect the critical states as well as their dynamic network biomarkers, but also help explore regulatory relationships between genes. Numerical simulation indicates that the DNFE method is robust and superior to existing methods. Furthermore, DNFE has predicted active transcription factors (TFs), and further identified dark genes, which are usually overlooked by traditional methods.

cancer biology↗

The Association between Alcohol Consumption and Telomere Length: A Meta-Analysis Focusing on Observational Studies

BackgroundBoth telomere length and alcohol consumption play important roles in carcinogenesis and biological age. Many efforts have been made to investigate the association between alcohol consumption and telomere length. However, no consensus has been reached yet.\n\nMethodsIn this article, we performed a meta-analysis to integrate the investigation results in the literature about the association between alcohol consumption and telomere length. After searching articles published between 2000 and 2016, 21 articles (including 27 analyses, total sample size 35,891) met our eligibility criteria.\n\nResultsWe found a significant association between alcohol consumption and telomere length (Fishers combined p-value = 3.52E-8 and Liptaks weighted p-value = 8.24E-3). We also found that the significance of the association between alcohol consumption and telomere length varies with study type (cohort, case-control, or cross-sectional) and study population (Europe, Asia, American, or Australia).\n\nConclusionsCombined evidence showed that alcohol consumption is associated with telomere length. The consistent quantifications of alcohol consumption and telomere length would benefit the future aggregation of the evidence from different studies.

cancer biology↗

Disrupting the leukemia niche in the central nervous system attenuates leukemia chemoresistance

Protection from acute lymphoblastic leukemia (ALL) relapse in the central nervous system (CNS) is crucial to survival and quality of life for ALL patients. Current CNS-directed therapies cause significant toxicities and are only partially effective. Moreover, the impact of the CNS microenvironment on leukemia biology is poorly understood. Herein, we showed that leukemia cells associated with the meninges of xenotransplanted mice, or co-cultured with meningeal cells, exhibit enhanced chemoresistance due to effects on both apoptosis balance and quiescence. From a mechanistic standpoint, we identified that leukemia chemoresistance is primarily mediated by direct leukemia-meningeal cell interactions and overcome by detaching the leukemia cells from the meninges. Next, we used a co-culture adhesion assay to identify drugs that disrupted leukemia-meningeal adhesion. In addition to identifying several drugs that inhibit canonical cell adhesion targets we found that Me6TREN, a novel hematopoietic stem cell (HSC) mobilizing compound, also disrupts leukemia-meningeal adhesion in vitro and in vivo. Finally, Me6TREN enhanced the efficacy of cytarabine in treating CNS leukemia in xenotransplanted mice. This work demonstrates that the meninges exert a critical influence on leukemia chemoresistance, elucidates mechanisms of CNS relapse beyond the well-described role of the blood-brain barrier, and identifies novel therapeutic approaches for overcoming chemoresistance.

cancer biology↗

Glioblastoma cell fate is differentially regulated by the microenvironments of the tumour bulk and infiltrative margin

Glioblastoma recurrence originates from invasive cells at the tumour margin that escape surgical debulking, but their biology remains poorly understood. Here we generated three somatic mouse models recapitulating the main glioblastoma driver mutations to characterise margin cells. We find that, regardless of genetics, tumours converge on a common set of neural- like cellular states. However, bulk and margin display distinct neurogenic patterns and immune microenvironments. The margin is immune-cold and preferentially follows developmental-like trajectories to produce astrocyte-like cells. In contrast, injury-like programmes dominate in the bulk, are associated with immune infiltration and generate lowly-proliferative injured neural progenitor-like (iNPCs) cells. In vivo label-retention approaches further demonstrate that iNPCs account for a significant proportion of dormant glioblastoma cells and are induced by interferon signalling within T-cell niches. These findings indicate that tumour region is a major determinant of glioblastoma cell fate and therapeutic vulnerabilities identified in bulk may not extend to the margin residuum.

cancer biology↗

Mutant IDH impairs chromatin binding by PDGFB to promote chromosome instability

Non-canonical roles for growth factors in the nucleus have been previously described, but their mechanism of action and biological roles remain enigmatic. Platelet-derived growth factor B (PDGFB) can drive formation of low-grade glioma and here we show that it localizes to the nucleus of human glioma cells where it binds chromatin to preserve genome stability and cell lineage. Failure of PDGFB to localize to the nucleus leads to chromosomal abnormalities, aberrant heterochromatin architecture and accelerated tumorigenesis. Furthermore, nuclear localization of PDGFB is reliant upon the expression levels and mutation status of isocitrate dehydrogenase (IDH). Unexpectedly, we identified macrophages as the predominant source of PDGFB in human, finding that immune-derived PDGFB can localize to the nucleus of glioma cells. Collectively, these studies show that immune derived PDGFB enters the nucleus of glioma cells to maintain genomic stability, while identifying a new mechanism by which IDH mutations promote gliomagenesis.

cancer biology↗

Functionally distinct ALK and ROS1 fusions detected in infant-type hemispheric gliomas converge on STAT3 and SHP2 activation

ALK and ROS1 fusions are emerging as key drivers of infant-type hemispheric gliomas (IHG). With diverse gene partners, the impact of ALK and ROS1 oncoprotein heterogeneity on glioma biology remains unknown. We developed an integrative phospho-proteomic and transcriptomic approach to discover biological functions regulated by five IHG-associated fusions: CCDC88A::ALK, PPP1CB::ALK, GOPC::ROS1, CLIP1::ROS1 and KIF21A::ROS1. Here, we report fusion-specific oncogenic functions conferred by the 5 gene partner, including increased cell motility driven by microtubule-interacting fusions CCDC88A::ALK and CLIP1::ROS1. All studied fusions converged on a non-canonical STAT3 activation. Using affinity purification mass spectrometry, we identify SHP2 in direct interaction with all three ROS1 oncoproteins, but with none of the ALK oncoproteins, which in turn interact with SHC1/SHC3. ROS1 fusions phosphorylated SHP2 to a larger extent than ALK fusions, and analyses of downstream pathways suggested MAPK-independent, non-canonical SHP2-driven functions. Our findings reveal both common and fusion-specific dependencies, offering opportunities to optimize therapeutic strategies for pediatric gliomas.

cancer biology↗