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Heterogeneity is a hallmark of cancer. The advent of single-cell technologies has helped uncover heterogeneity in a high-throughput manner in different cancers across varied contexts. Here we apply single-cell sequencing technologies to reveal inherent heterogeneity in assumptively monoclonal pancreatic cancer (PDAC) cell lines and patient-derived organoids (PDOs). Our findings reveal a high degree of both genomic and transcriptomic polyclonality in monolayer PDAC cell lines, custodial variation induced by growing apparently identical cell lines in different laboratories, and transcriptomic shifts in transitioning from 2D to 3D spheroid growth models. Our findings also call into question the validity of widely available immortalized, non-transformed pancreatic lines as contemporaneous “control” lines in experiments. We confirm these findings using a variety of independent assays, including but not limited to whole exome sequencing, single-cell copy number variation sequencing (scCNVseq), single-nuclei assay for transposase-accessible chromatin with sequencing, fluorescence in-situ hybridization, and single-cell RNA sequencing (scRNAseq). We map scRNA expression data to unique genomic clones identified by orthogonally-gathered scCNVseq data of these same PDAC cell lines. Further, while PDOs are known to reflect the cognate in vivo biology of the parental tumor, we identify transcriptomic shifts during ex vivo passage that might hamper their predictive abilities over time. The impact of these findings on rigor and reproducibility of experimental data generated using established preclinical PDAC models between and across laboratories is uncertain, but a matter of concern. It is unclear if the molecular profiles of pancreatic ductal adenocarcinoma (PDAC) preclinical models remain stable during propagation. Here, the authors characterise clonal evolution throughout propagation in PDAC cell lines and a patient-derived organoid using single-cell genomics, transcriptomics and epigenomics.

Background Limited accessibility of the tumour precludes longitudinal characterisation for therapy guidance in pancreatic ductal adenocarcinoma (PDAC). Methods We utilised dielectrophoresis-field flow fractionation (DEP-FFF) to isolate circulating tumour cells (CTCs) in 272 blood draws from 74 PDAC patients (41 localised, 33 metastatic) to non-invasively monitor disease progression. Results Analysis using multiplex imaging flow cytometry revealed four distinct sub-populations of CTCs: epithelial (E-CTC), mesenchymal (M-CTC), partial epithelial-mesenchymal transition (pEMT-CTC) and stem cell-like (SC-CTC). Overall, CTC detection rate was 76.8% (209/272 draws) and total CTC counts did not correlate with any clinicopathological variables. However, the proportion of pEMT-CTCs (prop-pEMT) was correlated with advanced disease, worse progression-free and overall survival in all patients, and earlier recurrence after resection. Conclusion Our results underscore the importance of immunophenotyping and quantifying specific CTC sub-populations in PDAC.

Liquid biopsies enable noninvasive tumor profiling and longitudinal disease monitoring. Their analytical performance is strongly influenced by pre‐analytical factors, yet direct comparisons between cell‐free DNA (cfDNA) and extracellular vesicle‐derived DNA (evDNA) remain scarce. We prospectively evaluated four pre‐analytical variables: processing delay, storage temperature, tube type, and plasma input volume, on cfDNA and evDNA from cancer patient plasma ( n = 244) using ddPCR, Qubit, and TapeStation. Key findings were validated in archived plasma samples ( n = 723). In the prospective cohort, cfDNA concentrations increased after 24 h and evDNA after 48 h at room temperature, while retrospective analysis revealed earlier changes (cfDNA: 6 h; evDNA: 24 h). Storage conditions influenced both analytes, as short‐term refrigeration (4 °C) better preserved DNA quality than −80 °C freezing, while extracted DNA remained stable at −80 °C. Acid citrate dextrose (ACD) and K 2 EDTA tubes performed similarly under prompt processing. Higher plasma volumes improved evDNA, but not cfDNA, for mutation detection. evDNA demonstrates greater resilience than cfDNA under suboptimal conditions. Standardized workflows and prompt processing are essential to ensure reliable mutation detection in clinical liquid biopsy applications.

Purpose Cancer of unknown primary (CUP) accounts for 2–5% of all cancer diagnoses, wherein standard investigations fail to reveal the original tumor site. Basket trials allocate targeted therapeutics based on actionable somatic mutations, independent of tumor entity. These trials, however, mostly rely on variants identified in tissue biopsies. Since liquid biopsies (LB) represent the overall tumor genomic landscape, they may provide an ideal diagnostic source in CUP patients. To identify the most informative liquid biopsy compartment, we compared the utility of genomic variant analysis for therapy stratification in two LB compartments (circulating cell-free (cf) and extracellular vesicle (ev) DNA). Methods CfDNA and evDNA from 23 CUP patients were analyzed using a targeted gene panel covering 151 genes. Identified genetic variants were interpreted regarding diagnostic and therapeutic relevance using the MetaKB knowledgebase. Results LB revealed a total of 22 somatic mutations in evDNA and/or cfDNA in 11/23 patients. Out of the 22 identified somatic variants, 14 are classified as Tier I druggable somatic variants. Comparison of variants identified in evDNA and cfDNA revealed an overlap of 58% of somatic variants in both LB compartments, whereas over 40% of variants were only found in one or the other compartment. Conclusion We observed substantial overlap between somatic variants identified in evDNA and cfDNA of CUP patients. Nonetheless, interrogation of both LB compartments can potentially increase the rate of druggable alterations, stressing the significance of liquid biopsies for possible primary-independent basket and umbrella trial inclusion.

Israel has always felt the tension between the claims of identity and freedom. It lies at the heart of controversies such as the 2018 nation-state law, the egalitarian prayer space at the Western Wall, marriage laws, and the exemption of Israeli Arabs from military service. Yet Israel’s commitment to democratic and liberal values for its citizens has been resilient and profound. Why? Part of the explanation is rooted in Jewish history and text. In Genesis, the usual hierarchical expectations of patriarchal authority passing from father to firstborn are repeatedly overturned—in the story of Ishmael and Isaac, and then of

Tubulin is a very important target for cancer-fighting therapies; therefore, the cancer research community continues to adopt new ways of developing the therapeutic potential of tubulin and tubulin-associated proteins. Two families of tubulin-associated kinases, Aurora and Polo-like, have received significant attention regarding how they contribute to tumorigenesis and can be targeted with selective small molecule inhibitors. Aurora and Polo-like kinases play essential roles in centrosome separation, chromosome alignment and segregation, and cytokinesis. Inhibition of any of these kinases results in abnormal mitotic events (which vary depending on the particular family member) and eventually leads to apoptosis. Because of the biological consequences of inhibiting these kinases, several Aurora or Polo-like selective inhibitors have advanced to various stages of preclinical and clinical development; the most advanced are currently in phase 2 clinical trials.

Ewing sarcoma provides an important model for transcription-factor-mediated oncogenic transformation because of its reliance on the ETS-type fusion oncoprotein EWS/FLI. EWS/FLI functions as a transcriptional activator and transcriptional activation is required for its oncogenic activity. Here, we demonstrate that a previously less-well characterized transcriptional repressive function of the EWS/FLI fusion is also required for the transformed phenotype of Ewing sarcoma. Through comparison of EWS/FLI transcriptional profiling and genome-wide localization data, we define the complement of EWS/FLI direct downregulated target genes. We demonstrate that LOX is a previously undescribed EWS/FLI-repressed target that inhibits the transformed phenotype of Ewing sarcoma cells. Mechanistic studies demonstrate that the NuRD co-repressor complex interacts with EWS/FLI, and that its associated histone deacetylase and LSD1 activities contribute to the repressive function. Taken together, these data reveal a previously unknown molecular function for EWS/FLI, demonstrate a more highly coordinated oncogenic transcriptional hierarchy mediated by EWS/FLI than previously suspected, and implicate a new paradigm for therapeutic intervention aimed at controlling NuRD activity in Ewing sarcoma tumors.

A method to identify genomic elements that promote cap-independent translation is described and is used to identify such elements in the human genome. We report an in vitro selection strategy to identify RNA sequences that mediate cap-independent initiation of translation. This method entails mRNA display of trillions of genomic fragments, selection for initiation of translation and high-throughput deep sequencing. We identified >12,000 translation-enhancing elements (TEEs) in the human genome, generated a high-resolution map of human TEE-bearing regions (TBRs), and validated the function of a subset of sequences in vitro and in cultured cells.