All Publications
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Deciphering the impact of genomic variation on function.
Nature
2024; 633 (8028): 47-57
Abstract
Our genomes influence nearly every aspect of human biology-from molecular and cellular functions to phenotypes in health and disease. Studying the differences in DNA sequence between individuals (genomic variation) could reveal previously unknown mechanisms of human biology, uncover the basis of genetic predispositions to diseases, and guide the development of new diagnostic tools and therapeutic agents. Yet, understanding how genomic variation alters genome function to influence phenotype has proved challenging. To unlock these insights, we need a systematic and comprehensive catalogue of genome function and the molecular and cellular effects of genomic variants. Towards this goal, the Impact of Genomic Variation on Function (IGVF) Consortium will combine approaches in single-cell mapping, genomic perturbations and predictive modelling to investigate the relationships among genomic variation, genome function and phenotypes. IGVF will create maps across hundreds of cell types and states describing how coding variants alter protein activity, how noncoding variants change the regulation of gene expression, and how such effects connect through gene-regulatory and protein-interaction networks. These experimental data, computational predictions and accompanying standards and pipelines will be integrated into an open resource that will catalyse community efforts to explore how our genomes influence biology and disease across populations.
View details for DOI 10.1038/s41586-024-07510-0
View details for PubMedID 39232149
View details for PubMedCentralID 7405896
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Deterministic evolution and stringent selection during preneoplasia.
Nature
2023
Abstract
The earliest events during human tumour initiation, although poorly characterized, may hold clues to malignancy detection and prevention1. Here we model occult preneoplasia by biallelic inactivation of TP53, a common early event in gastric cancer, in human gastric organoids. Causal relationships between this initiating genetic lesion and resulting phenotypes were established using experimental evolution in multiple clonally derived cultures over 2 years. TP53 loss elicited progressive aneuploidy, including copy number alterations and structural variants prevalent in gastric cancers, with evident preferred orders. Longitudinal single-cell sequencing of TP53-deficient gastric organoids similarly indicates progression towards malignant transcriptional programmes. Moreover, high-throughput lineage tracing with expressed cellular barcodes demonstrates reproducible dynamics whereby initially rare subclones with shared transcriptional programmes repeatedly attain clonal dominance. This powerful platform for experimental evolution exposes stringent selection, clonal interference and a marked degree of phenotypic convergence in premalignant epithelial organoids. These data imply predictability in the earliest stages of tumorigenesis and show evolutionary constraints and barriers to malignant transformation, with implications for earlier detection and interception of aggressive, genome-instable tumours.
View details for DOI 10.1038/s41586-023-06102-8
View details for PubMedID 37258665
View details for PubMedCentralID 5656752
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APOBEC3G protects the genome of human cultured cells and mice from radiation-induced damage.
The FEBS journal
2022
Abstract
Cytosine deaminases AID/APOBEC proteins act as potent nucleic-acid editors, playing important roles in innate and adaptive immunity. However, the mutagenic effects of some of these proteins compromise genomic integrity and may promote tumorigenesis. Here, we demonstrate that human APOBEC3G (A3G), in addition to its role in innate immunity, promotes repair of double-strand breaks (DSBs) in vitro and in vivo. Transgenic mice expressing A3G successfully survived lethal irradiation, whereas wild-type controls quickly succumbed to radiation syndrome. Mass spectrometric analyses identified the differential up-regulation of a plethora of proteins involved in DSB repair pathways in A3G-expressing cells early following irradiation to facilitate repair. Importantly, we find that A3G not only accelerates DSB repair, but also promotes deamination-dependent error-free rejoining. These findings have two implications: (i) strategies aimed at inhibiting A3G may improve the efficacy of genotoxic therapies used to cure malignant tumors; and (ii) enhancing A3G activity may reduce acute radiation syndrome in individuals exposed to ionizing radiation.
View details for DOI 10.1111/febs.16673
View details for PubMedID 36325681
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Spatial proteomic characterization of HER2-positive breast tumors through neoadjuvant therapy predicts response
NATURE CANCER
2021; 2 (4): 400-+
View details for DOI 10.1038/s43018-021-00190-z
View details for Web of Science ID 000644945500004
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Spatial proteomic characterization of HER2-positive breast tumors through neoadjuvant therapy predicts response.
Nature cancer
2021; 2 (4): 400-413
Abstract
The addition of HER2-targeted agents to neoadjuvant chemotherapy has dramatically improved pathological complete response (pCR) rates in early-stage, HER2-positive breast cancer. Nonetheless, up to 50% of patients have residual disease after treatment, while others are likely overtreated. Here, we performed multiplex spatial proteomic characterization of 122 samples from 57 HER2-positive breast tumors from the neoadjuvant TRIO-US B07 clinical trial sampled pre-treatment, after 14-21 d of HER2-targeted therapy and at surgery. We demonstrated that proteomic changes after a single cycle of HER2-targeted therapy aids the identification of tumors that ultimately undergo pCR, outperforming pre-treatment measures or transcriptomic changes. We further developed and validated a classifier that robustly predicted pCR using a single marker, CD45, measured on treatment, and showed that CD45-positive cell counts measured via conventional immunohistochemistry perform comparably. These results demonstrate robust biomarkers that can be used to enable the stratification of sensitive tumors early during neoadjuvant HER2-targeted therapy, with implications for tailoring subsequent therapy.
View details for DOI 10.1038/s43018-021-00190-z
View details for PubMedID 34966897
View details for PubMedCentralID PMC8713949
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The Human Tumor Atlas Network: Charting Tumor Transitions across Space and Time at Single-Cell Resolution.
Cell
2020; 181 (2): 236–49
Abstract
Crucial transitions in cancer-including tumor initiation, local expansion, metastasis, and therapeutic resistance-involve complex interactions between cells within the dynamic tumor ecosystem. Transformative single-cell genomics technologies and spatial multiplex in situ methods now provide an opportunity to interrogate this complexity at unprecedented resolution. The Human Tumor Atlas Network (HTAN), part of the National Cancer Institute (NCI) Cancer Moonshot Initiative, will establish a clinical, experimental, computational, and organizational framework to generate informative and accessible three-dimensional atlases of cancer transitions for a diverse set of tumor types. This effort complements both ongoing efforts to map healthy organs and previous large-scale cancer genomics approaches focused on bulk sequencing at a single point in time. Generating single-cell, multiparametric, longitudinal atlases and integrating them with clinical outcomes should help identify novel predictive biomarkers and features as well as therapeutically relevant cell types, cell states, and cellular interactions across transitions. The resulting tumor atlases should have a profound impact on our understanding of cancer biology and have the potential to improve cancer detection, prevention, and therapeutic discovery for better precision-medicine treatments of cancer patients and those at risk for cancer.
View details for DOI 10.1016/j.cell.2020.03.053
View details for PubMedID 32302568
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Tumor expression and microenvironment in HER2-positive breast cancer before and on HER2-targeted therapy: Analysis of microarray expression data from the TRIO-US B07 trial
AMER ASSOC CANCER RESEARCH. 2020
View details for DOI 10.1158/1538-7445.SABCS19-P4-07-01
View details for Web of Science ID 000527012502113
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Pathologic and molecular responses to neoadjuvant trastuzumab and/or lapatinib from a phase II randomized trial in HER2-positive breast cancer (TRIO-US B07).
Nature communications
2020; 11 (1): 5824
Abstract
In this multicenter, open-label, randomized phase II investigator-sponsored neoadjuvant trial with funding provided by Sanofi and GlaxoSmithKline (TRIO-US B07, Clinical Trials NCT00769470), participants with early-stage HER2-positive breast cancer (N=128) were recruited from 13 United States oncology centers throughout the Translational Research in Oncology network. Participants were randomized to receive trastuzumab (T; N=34), lapatinib (L; N=36), or both (TL; N=58) as HER2-targeted therapy, with each participant given one cycle of this designated anti-HER2 therapy alone followed by six cycles of standard combination chemotherapy with the same anti-HER2 therapy. The primary objective was to estimate the rate of pathologic complete response (pCR) at the time of surgery in each of the three arms. In the intent-to-treat population, we observed similar pCR rates between T (47%, 95% confidence interval [CI] 30-65%) and TL (52%, 95% CI 38-65%), and a lower pCR rate with L (25%, 95% CI 13-43%). In the T arm, 100% of participants completed all protocol-specified treatment prior to surgery, as compared to 69% in the L arm and 74% in the TL arm. Tumor or tumor bed tissue was collected whenever possible pre-treatment (N=110), after one cycle of HER2-targeted therapy alone (N=89), and at time of surgery (N=59). Higher-level amplification of HER2 and hormone receptor (HR)-negative status were associated with a higher pCR rate. Large shifts in the tumor, immune, and stromal gene expression occurred after one cycle of HER2-targeted therapy. In contrast to pCR rates, the L-containing arms exhibited greater proliferation reduction than T at this timepoint. Immune expression signatures increased in all arms after one cycle of HER2-targeted therapy, decreasing again by the time of surgery. Our results inform approaches to early assessment of sensitivity to anti-HER2 therapy and shed light on the role of the immune microenvironment in response to HER2-targeted agents.
View details for DOI 10.1038/s41467-020-19494-2
View details for PubMedID 33203854
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RNF20 and USP44 Regulate Stem Cell Differentiation by Modulating H2B Monoubiquitylation
MOLECULAR CELL
2012; 46 (5): 662-673
Abstract
Embryonic stem cells (ESCs) maintain high genomic plasticity, which is essential for their capacity to enter diverse differentiation pathways. Posttranscriptional modifications of chromatin histones play a pivotal role in maintaining this plasticity. We now report that one such modification, monoubiquitylation of histone H2B on lysine 120 (H2Bub1), catalyzed by the E3 ligase RNF20, increases during ESC differentiation and is required for efficient execution of this process. This increase is particularly important for the transcriptional induction of relatively long genes during ESC differentiation. Furthermore, we identify the deubiquitinase USP44 as a negative regulator of H2B ubiquitylation, whose downregulation during ESC differentiation contributes to the increase in H2Bub1. Our findings suggest that optimal ESC differentiation requires dynamic changes in H2B ubiquitylation patterns, which must occur in a timely and well-coordinated manner.
View details for DOI 10.1016/j.molcel.2012.05.023
View details for Web of Science ID 000305095400015
View details for PubMedID 22681888
View details for PubMedCentralID PMC3374598