Publications by authors named "Dan Landau"

Acute myeloid leukemia (AML) is a complex cancer, yet advances in recent years from integrated genomics methods have helped improve diagnosis, treatment, and means of patient stratification. A recent example of a powerful, multimodal method is DOGMA-seq, which can measure chromatin accessibility, gene expression, and cell-surface protein levels from the same individual cell simultaneously. Previous bimodal single-cell techniques, such as CITE-seq (Cellular indexing of transcriptomes and epitopes), have only permitted the transcriptome and cell-surface protein expression measurement.

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The presence of circulating tumor DNA (ctDNA) in patients with colorectal adenomas remains uncertain. Studies using tumor-agnostic approaches report ctDNA in 10-15% of patients, though with uncertainty as to whether the signal originates from the adenoma. To obtain an accurate estimate of the proportion of patients with ctDNA, a sensitive tumor-informed strategy is preferred, as it ensures the detected signal originates from the adenoma.

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Gene expression is coordinated by a multitude of transcription factors (TFs), whose binding to the genome is directed through multiple interconnected epigenetic signals, including chromatin accessibility and histone modifications. These complex networks have been shown to be disrupted during aging, disease, and cancer. However, profiling these networks across diverse cell types and states has been limited due to the technical constraints of existing methods for mapping DNA:Protein interactions in single cells.

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  • * The study reveals that RAS mutations transform specific blood cell progenitors (granulocyte-monocyte progenitors) that have already acquired other mutations, suggesting advanced leukemia can arise from different cell types than initial clones.
  • * RAS-mutant leukemia stem cells show resistance to the treatment drug venetoclax due to changes in gene expression, leading to worse treatment responses and relapses characterized by monocytic features, highlighting the impact of genetic drivers on therapy effectiveness.
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  • CRISPRmap is a new method for optical pooled genetic screening that allows researchers to study spatial phenotypes without destroying cells, focusing on how cells respond to CRISPR modifications.
  • This method integrates guide-identifying barcodes with advanced imaging techniques like immunofluorescence and RNA detection to improve the efficiency of reading the genetic information.
  • In a study using breast cancer cells, CRISPRmap helped identify potentially harmful gene mutations associated with DNA damage repair, providing insights into their impact on treatment responses.
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Single-cell sequencing has characterized cell state heterogeneity across diverse healthy and malignant tissues. However, the plasticity or heritability of these cell states remains largely unknown. To address this, we introduce PATH (phylogenetic analysis of trait heritability), a framework to quantify cell state heritability versus plasticity and infer cell state transition and proliferation dynamics from single-cell lineage tracing data.

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In solid tumor oncology, circulating tumor DNA (ctDNA) is poised to transform care through accurate assessment of minimal residual disease (MRD) and therapeutic response monitoring. To overcome the sparsity of ctDNA fragments in low tumor fraction (TF) settings and increase MRD sensitivity, we previously leveraged genome-wide mutational integration through plasma whole-genome sequencing (WGS). Here we now introduce MRD-EDGE, a machine-learning-guided WGS ctDNA single-nucleotide variant (SNV) and copy-number variant (CNV) detection platform designed to increase signal enrichment.

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Somatic mosaicism is a hallmark of malignancy that is also pervasively observed in human physiological aging, with clonal expansions of cells harboring mutations in recurrently mutated driver genes. Bulk sequencing of tissue microdissection captures mutation frequencies, but cannot distinguish which mutations co-occur in the same clones to reconstruct clonal architectures, nor phenotypically profile clonal populations to delineate how driver mutations impact cellular behavior. To address these challenges, we developed single-cell Genotype-to-Phenotype sequencing (scG2P) for high-throughput, highly-multiplexed, single-cell joint capture of recurrently mutated genomic regions and mRNA phenotypic markers in cells or nuclei isolated from solid tissues.

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  • Somatic mutations can change chromatin accessibility, impacting how cells differentiate and causing abnormal growth, but studying this in human samples is complicated due to mixed cell types.* -
  • The researchers created a technique called GoT-ChA, which connects specific genotypes to chromatin accessibility at a single-cell level, allowing for analysis of thousands of cells simultaneously.* -
  • Their study on JAK2-mutant CD34 cells revealed that mutations lead to specific epigenetic changes that affect inflammation and differentiation, demonstrating the potential of GoT-ChA for exploring the relationship between somatic mutations and epigenetic changes in various cellular contexts.*
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  • * Researchers used advanced RNA-sequencing techniques on tumor samples taken from patients after four weeks of IDHi treatment to examine cellular changes.
  • * Findings reveal that IDHi promotes differentiation of tumor cells toward a specific brain cell type (astrocytes), reduces stem-like cells, and highlights a mutation (NOTCH1) that may hinder this differentiation and affect treatment response.
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Studying RNA splicing factor mutations is challenging due to difficulties in distinguishing wild-type and mutant cells within complex human tissues and inaccuracies associated with reconstructing splicing signals from short-read sequencing data. Here, we present Genotyping of Transcriptomes (GoT)-Splice, a protocol that overcomes these limitations by combining GoT with enhanced long-read single-cell transcriptome and cell-surface proteomics profiling. We describe steps for long-read library preparation and analysis, followed by cDNA re-amplification, enrichment of mutation of interest, sample indexing, and GoT library preparation.

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Pooled genetic screens are powerful tools to study gene function in a high-throughput manner. Typically, sequencing-based screens require cell lysis, which limits the examination of critical phenotypes such as cell morphology, protein subcellular localization, and cell-cell/tissue interactions. In contrast, emerging optical pooled screening methods enable the investigation of these spatial phenotypes in response to targeted CRISPR perturbations.

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Unlabelled: Gain-of-function mutations activating JAK/STAT signaling are seen in the majority of patients with myeloproliferative neoplasms (MPN), most commonly JAK2V617F. Although clinically approved JAK inhibitors improve symptoms and outcomes in MPNs, remissions are rare, and mutant allele burden does not substantively change with chronic therapy. We hypothesized this is due to limitations of current JAK inhibitors to potently and specifically abrogate mutant JAK2 signaling.

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Stem cells regulate their self-renewal and differentiation fate outcomes through both symmetric and asymmetric divisions. mA RNA methylation controls symmetric commitment and inflammation of hematopoietic stem cells (HSCs) through unknown mechanisms. Here, we demonstrate that the nuclear speckle protein SON is an essential mA target required for murine HSC self-renewal, symmetric commitment, and inflammation control.

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Unlabelled: Cancer cells adapt and survive through the acquisition and selection of molecular modifications. This process defines cancer evolution. Building on a theoretical framework based on heritable genetic changes has provided insights into the mechanisms supporting cancer evolution.

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Tumor-infiltrating macrophages support critical steps in tumor progression, and their accumulation in the tumor microenvironment (TME) is associated with adverse outcomes and therapeutic resistance across human cancers. In the TME, macrophages adopt diverse phenotypic alterations, giving rise to heterogeneous immune activation states and induction of cell cycle. While the transcriptional profiles of these activation states are well-annotated across human cancers, the underlying signals that regulate macrophage heterogeneity and accumulation remain incompletely understood.

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Article Synopsis
  • RNA splicing factors often mutate in blood disorders like myelodysplastic syndrome (MDS), affecting how blood cells develop, but the role of these mutations in blood formation is still not fully understood.
  • Researchers used a new method, GoT-Splice, which combines gene profiling and advanced single-cell analysis to study how mutations in a specific splicing factor (SF3B1) influence blood progenitor cells.
  • Their findings showed that SF3B1 mutations lead to abnormal splicing patterns and an increase in specific blood cell types before MDS is clinically evident, highlighting the importance of understanding these mutations in early disease progression.
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Chromosomal instability (CIN) and epigenetic alterations are characteristics of advanced and metastatic cancers, but whether they are mechanistically linked is unknown. Here we show that missegregation of mitotic chromosomes, their sequestration in micronuclei and subsequent rupture of the micronuclear envelope profoundly disrupt normal histone post-translational modifications (PTMs), a phenomenon conserved across humans and mice, as well as in cancer and non-transformed cells. Some of the changes in histone PTMs occur because of the rupture of the micronuclear envelope, whereas others are inherited from mitotic abnormalities before the micronucleus is formed.

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Spatial transcriptomics and proteomics provide complementary information that independently transformed our understanding of complex biological processes. However, experimental integration of these modalities is limited. To overcome this, we developed Spatial PrOtein and Transcriptome Sequencing (SPOTS) for high-throughput simultaneous spatial transcriptomics and protein profiling.

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Chromatin states are functionally defined by a complex combination of histone modifications, transcription factor binding, DNA accessibility and other factors. Current methods for defining chromatin states cannot measure more than one aspect in a single experiment at single-cell resolution. Here we introduce nanobody-tethered transposition followed by sequencing (NTT-seq), an assay capable of measuring the genome-wide presence of up to three histone modifications and protein-DNA binding sites at single-cell resolution.

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Somatic mutations in cancer genes have been detected in clonal expansions across healthy human tissue, including in clonal hematopoiesis. However, because mutated and wild-type cells are admixed, we have limited ability to link genotypes with phenotypes. To overcome this limitation, we leveraged multi-modality single-cell sequencing, capturing genotype, transcriptomes and methylomes in progenitors from individuals with DNMT3A R882 mutated clonal hematopoiesis.

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Liquid biopsy detection of residual cancer after therapy offers to transform oncology care. Nonetheless, in the residual cancer context, signals are sparse and are hindered by technical sequencing noise. Kurtz et al.

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The liver vascular network is patterned by sinusoidal and hepatocyte co-zonation. How intra-liver vessels acquire their hierarchical specialized functions is unknown. We study heterogeneity of hepatic vascular cells during mouse development through functional and single-cell RNA-sequencing.

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