Dr. Zhang is currently a Research Engineer at the Department of Biomedical Data Science and the Center for Cancer Systems Biology, Stanford School of Medicine. Dr. Zhang obtained her M.S. and Ph.D. in Electrical Engineering, both from Stanford University. Her Ph.D. studies focused on developing computational algorithms for metabolomics data analysis, in which she received Young Scientist Award from the Metabolomics Society for her algorithm on metabolic network analysis delineating the effects of genetic mutants and drug treatment on the metabolome. Her postdoctoral studies at the Department of Radiology, Stanford School of Medicine, integrated radiomic data and genomic data that identified a prognostic metabolic regulation biomarker for non-small cell lung cancer. Her current research primarily focuses on developing and implementing novel computational methods to integrate and analyze single-cell multi-omics data, such as single-cell RNA sequencing, spatial proteomics and spatial transcriptomics. She has developed algorithms to solve computational challenges of spatial omics data and to identify mediators for cell-cell interactions associated with metastasis that was featured in Stanford Medicine Magazine. Dr. Zhang has authored and co-authored publications including Nature, Cell, Nature Methods etc. Her research aims at bridging multi-omics, imaging, machine learning, artificial intelligence to better understand biology for cancer progression and immunosuppression.
Honors & Awards
University Biomedical Informatics Research Training Award, NLM, National Institutes of Health (2020)
Young Scientist Award, The Metabolomics Society (2013)
First Class Honor, National University of Singapore (2009)
Education & Certifications
BE, National University of Singapore, Electrical Engineering (2009)
MS, Stanford University, Electrical Engineering (2011)
PhD, Stanford University, Electrical Engineering, Bioinformatics (2015)
Service, Volunteer and Community Work
Staff representative, JEDI (Justice, Equity, Diversity, and Inclusion) committee, Department of Biomedical Data Science, Stanford University (2022 - Present)
The colocatome as a spatial -omic reveals shared microenvironment features between tumour-stroma assembloids and human lung cancer.
bioRxiv : the preprint server for biology
Computational frameworks to quantify and compare microenvironment spatial features of in-vitro patient-derived models and clinical specimens are needed. Here, we acquired and analysed multiplexed immunofluorescence images of human lung adenocarcinoma (LUAD) alongside tumour-stroma assembloids constructed with organoids and fibroblasts harvested from the leading edge (Tumour-Adjacent Fibroblasts;TAFs) or core (Tumour Core Fibroblasts;TCFs) of human LUAD. We introduce the concept of the "colocatome" as a spatial -omic dimension to catalogue all proximate and distant colocalisations between malignant and fibroblast subpopulations in both the assembloids and clinical specimens. The colocatome expands upon the colocalisation quotient (CLQ) through a nomalisation strategy that involves permutation analysis and thereby allows comparisons of CLQs under different conditions. Using colocatome analysis, we report that both TAFs and TCFs protected cancer cells from targeted oncogene treatment by uniquely reorganising the tumour-stroma cytoarchitecture, rather than by promoting cellular heterogeneity or selection. Moreover, we show that the assembloids' colocatome recapitulates the tumour-stroma cytoarchitecture defining the tumour microenvironment of LUAD clinical samples and thereby can serve as a functional spatial readout to guide translational discoveries.
View details for DOI 10.1101/2023.09.11.557278
View details for PubMedID 37745466
View details for PubMedCentralID PMC10515823
Galectin-1 mediates chronic STING activation in tumors to promote metastasis through MDSC recruitment.
The immune system plays a crucial role in the regulation of metastasis. Tumor cells systemically change immune functions to facilitate metastatic progression. Through this study, we deciphered how tumoral Galectin-1 (Gal1) expression shapes the systemic immune environment to promote metastasis in head and neck cancer (HNC). In multiple preclinical models of HNC and lung cancer in immunogenic mice, Gal1 fostered the establishment of a pre-metastatic niche through polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs), which altered the local microenvironment to support metastatic spread. RNA sequencing of MDSCs from pre-metastatic lungs in these models demonstrated the role of PMN-MDSCs in collagen and extracellular matrix remodeling in the pre-metastatic compartment. Gal1 promoted MDSC accumulation in the pre-metastatic niche through the NF-κB signaling axis, triggering enhanced CXCL2-mediated MDSC migration. Mechanistically, Gal1 sustained NF-κB activation in tumor cells by enhancing STING protein stability, leading to prolonged inflammation-driven MDSC expansion. These findings suggest an unexpected pro-tumoral role of STING activation in metastatic progression and establish Gal1 as an endogenous positive regulator of STING in advanced-stage cancers.
View details for DOI 10.1158/0008-5472.CAN-23-0046
View details for PubMedID 37409887
Organization of the human intestine at single-cell resolution.
2023; 619 (7970): 572-584
The intestine is a complex organ that promotes digestion, extracts nutrients, participates in immune surveillance, maintains critical symbiotic relationships with microbiota and affects overall health1. The intesting has a length of over nine metres, along which there are differences in structure and function2. The localization of individual cell types, cell type development trajectories and detailed cell transcriptional programs probably drive these differences in function. Here, to better understand these differences, we evaluated the organization of single cells using multiplexed imaging and single-nucleus RNA and open chromatin assays across eight different intestinal sites from nine donors. Through systematic analyses, we find cell compositions that differ substantially across regions of the intestine and demonstrate the complexity of epithelial subtypes, and find that the same cell types are organized into distinct neighbourhoods and communities, highlighting distinct immunological niches that are present in the intestine. We also map gene regulatory differences in these cells that are suggestive of a regulatory differentiation cascade, and associate intestinal disease heritability with specific cell types. These results describe the complexity of the cell composition, regulation and organization for this organ, and serve as an important reference map for understanding human biology and disease.
View details for DOI 10.1038/s41586-023-05915-x
View details for PubMedID 37468586
View details for PubMedCentralID PMC10356619
NFE2L2 mutations enhance radioresistance in head and neck cancer by modulating intratumoral myeloid cells.
Radiotherapy is one of the primary treatments of head and neck squamous cell carcinoma (HNSCC), which has a high risk of locoregional failure (LRF). Presently, there is no reliable predictive biomarker of radioresistance in HNSCC. Here, we found that mutations in NFE2L2, which encodes Nrf2, are associated with a significantly higher rate of LRF in patients with oral cavity cancer treated with surgery and adjuvant (chemo)radiotherapy but not in those treated with surgery alone. Somatic mutation of NFE2L2 led to Nrf2 activation and radioresistance in HNSCC cells. Tumors harboring mutant Nrf2E79Q were substantially more radioresistant than tumors with wild-type Nrf2 in immunocompetent mice, while the difference was diminished in immunocompromised mice. Nrf2E79Q enhanced radioresistance through increased recruitment of intratumoral polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) and reduction of M1-polarized macrophages. Treatment with the glutaminase inhibitor CB-839 overcame the radioresistance induced by Nrf2E79Q or Nrf2E79K. Radiotherapy increased expression of PMN-MDSC-attracting chemokines, including CXCL1, CXLC3 and CSF3, in Nrf2E79Q-expressing tumors via the TLR4, which could be reversed by CB-839. This study provides insights into the impact of NFE2L2 mutations on radioresistance and suggests that CB-839 can increase radiosensitivity by switching intratumoral myeloid cells to an anti-tumor phenotype, supporting clinical testing of CB-839 with radiation in HNSCC with NFE2L2 mutations.
View details for DOI 10.1158/0008-5472.CAN-22-1903
View details for PubMedID 36652552
Identification of cell types in multiplexed in situ images by combining protein expression and spatial information using CELESTA.
Advances in multiplexed in situ imaging are revealing important insights in spatial biology. However, cell type identification remains a major challenge in imaging analysis, with most existing methods involving substantial manual assessment and subjective decisions for thousands of cells. We developed an unsupervised machine learning algorithm, CELESTA, which identifies the cell type of each cell, individually, using the cell's marker expression profile and, when needed, its spatial information. We demonstrate the performance of CELESTA on multiplexed immunofluorescence images of colorectal cancer and head and neck squamous cell carcinoma (HNSCC). Using the cell types identified by CELESTA, we identify tissue architecture associated with lymph node metastasis in HNSCC, and validate our findings in an independent cohort. By coupling our spatial analysis with single-cell RNA-sequencing data on proximal sections of the same specimens, we identify cell-cell crosstalk associated with lymph node metastasis, demonstrating the power of CELESTA to facilitate identification of clinically relevant interactions.
View details for DOI 10.1038/s41592-022-01498-z
View details for PubMedID 35654951
Lymph node colonization induces tumor-immune tolerance to promote distant metastasis.
For many solid malignancies, lymph node (LN) involvement represents a harbinger of distant metastatic disease and, therefore, an important prognostic factor. Beyond its utility as a biomarker, whether and how LN metastasis plays an active role in shaping distant metastasis remains an open question. Here, we develop a syngeneic melanoma mouse model of LN metastasis to investigate how tumors spread to LNs and whether LN colonization influences metastasis to distant tissues. We show that an epigenetically instilled tumor-intrinsic interferon response program confers enhanced LN metastatic potential by enabling the evasion of NK cells and promoting LN colonization. LN metastases resist T cell-mediated cytotoxicity, induce antigen-specific regulatory T cells, and generate tumor-specific immune tolerance that subsequently facilitates distant tumor colonization. These effects extend to human cancers and other murine cancer models, implicating a conserved systemic mechanism by which malignancies spread to distant organs.
View details for DOI 10.1016/j.cell.2022.04.019
View details for PubMedID 35525247
Multi-omics analysis of spatially distinct stromal cells reveals tumor-induced O-glycosylation of the CDK4-pRB axis in fibroblasts at the invasive tumor edge.
The invasive leading edge represents a potential gateway for tumor metastasis. The role of fibroblasts from the tumor edge in promoting cancer invasion and metastasis has not been comprehensively elucidated. We hypothesize that crosstalk between tumor and stromal cells within the tumor microenvironment (TME) results in activation of key biological pathways depending on their position in the tumor (edge vs core). Here we highlight phenotypic differences between tumor-adjacent-fibroblasts (TAF) from the invasive edge and tumor core fibroblasts (TCF) from the tumor core, established from human lung adenocarcinomas. A multi-omics approach that includes genomics, proteomics, and O-glycoproteomics was used to characterize crosstalk between TAFs and cancer cells. These analyses showed that O-glycosylation, an essential post-translational modification resulting from sugar metabolism, alters key biological pathways including the cyclin-dependent kinase 4 and phosphorylated retinoblastoma protein (CDK4-pRB) axis in the stroma and indirectly modulates pro-invasive features of cancer cells. In summary, the O-glycoproteome represents a new consideration for important biological processes involved in tumor-stroma crosstalk and a potential avenue to improve the anti-cancer efficacy of CDK4 inhibitors.
View details for DOI 10.1158/0008-5472.CAN-21-1705
View details for PubMedID 34853070
- Lymph node colonization promotes distant tumor metastasis through the induction of tumor-specific immunosuppression AMER ASSOC CANCER RESEARCH. 2020
Lymph node colonization promotes distant tumor metastasis through the induction of tumor-specific immunosuppression.
AMER ASSOC CANCER RESEARCH. 2020: 25–26
View details for Web of Science ID 000537844900026
- Lymph node colonization promotes distant tumor metastasis through the induction of systemic immune tolerance AMER ASSOC CANCER RESEARCH. 2019
A radiogenomic dataset of non-small cell lung cancer.
2018; 5: 180202
Medical image biomarkers of cancer promise improvements in patient care through advances in precision medicine. Compared to genomic biomarkers, image biomarkers provide the advantages of being non-invasive, and characterizing a heterogeneous tumor in its entirety, as opposed to limited tissue available via biopsy. We developed a unique radiogenomic dataset from a Non-Small Cell Lung Cancer (NSCLC) cohort of 211 subjects. The dataset comprises Computed Tomography (CT), Positron Emission Tomography (PET)/CT images, semantic annotations of the tumors as observed on the medical images using a controlled vocabulary, and segmentation maps of tumors in the CT scans. Imaging data are also paired with results of gene mutation analyses, gene expression microarrays and RNA sequencing data from samples of surgically excised tumor tissue, and clinical data, including survival outcomes. This dataset was created to facilitate the discovery of the underlying relationship between tumor molecular and medical image features, as well as the development and evaluation of prognostic medical image biomarkers.
View details for PubMedID 30325352
- A radiogenomic dataset of non-small cell lung cancer SCIENTIFIC DATA 2018; 5
- Studying tumor metabolic reprogramming through integration of metabolomics and transcriptomics AMER ASSOC CANCER RESEARCH. 2018
- GFPT2-Expressing Cancer-Associated Fibroblasts Mediate Metabolic Reprogramming in Human Lung Adenocarcinoma CANCER RESEARCH 2018; 78 (13): 3445–57
GFPT2-expressing cancer-associated fibroblasts mediate metabolic reprogramming in human lung adenocarcinoma.
Metabolic reprogramming of the tumor microenvironment is recognized as a cancer hallmark. To identify new molecular processes associated with tumor metabolism, we analyzed the transcriptome of bulk and flow-sorted human primary non-small cell lung cancer (NSCLC) together with 18FDG-positron emission tomography scans, which provide a clinical measure of glucose uptake. Tumors with higher glucose uptake were functionally enriched for molecular processes associated with invasion in adenocarcinoma (AD) and cell growth in squamous cell carcinoma (SCC). Next, we identified genes correlated to glucose uptake that were predominately overexpressed in a single cell-type comprising the tumor microenvironment. For SCC, most of these genes were expressed by malignant cells, whereas in AD they were predominately expressed by stromal cells, particularly cancer-associated fibroblasts (CAFs). Among these AD genes correlated to glucose uptake, we focused on Glutamine-Fructose-6-Phosphate Transaminase 2 (GFPT2), which codes for the Glutamine-Fructose-6-Phosphate Aminotransferase 2 (GFAT2), a rate-limiting enzyme of the hexosamine biosynthesis pathway (HBP), which is responsible for glycosylation. GFPT2 was predictive of glucose uptake independent of GLUT1, the primary glucose transporter, and was prognostically significant at both gene and protein level. We confirmed that normal fibroblasts transformed to CAF-like cells, following TGF-beta treatment, upregulated HBP genes, including GFPT2, with less change in genes driving glycolysis, pentose phosphate pathway and TCA cycle. Our work provides new evidence of histology-specific tumor-stromal properties associated with glucose uptake in NSCLC and identifies GFPT2 as a critical regulator of tumor metabolic reprogramming in AD.
View details for PubMedID 29760045
Towards in vivo estimation of reaction kinetics using high-throughput metabolomics data: a maximum likelihood approach
BMC SYSTEMS BIOLOGY
High-throughput assays such as mass spectrometry have opened up the possibility for large-scale in vivo measurements of the metabolome. This data could potentially be used to estimate kinetic parameters for many metabolic reactions. However, high-throughput in vivo measurements have special properties that are not taken into account in existing methods for estimating kinetic parameters, including significant relative errors in measurements of metabolite concentrations and reaction rates, and reactions with multiple substrates and products, which are sometimes reversible. A new method is needed to estimate kinetic parameters taking into account these factors.A new method, InVEst (In Vivo Estimation), is described for estimating reaction kinetic parameters, which addresses the specific challenges of in vivo data. InVEst uses maximum likelihood estimation based on a model where all measurements have relative errors. Simulations show that InVEst produces accurate estimates for a reversible enzymatic reaction with multiple reactants and products, that estimated parameters can be used to predict the effects of genetic variants, and that InVEst is more accurate than general least squares and graphic methods on data with relative errors. InVEst uses the bootstrap method to evaluate the accuracy of its estimates.InVEst addresses several challenges of in vivo data, which are not taken into account by existing methods. When data have relative errors, InVEst produces more accurate and robust estimates. InVEst also provides useful information about estimation accuracy using bootstrapping. It has potential applications of quantifying the effects of genetic variants, inference of the target of a mutation or drug treatment and improving flux estimation.
View details for DOI 10.1186/s12918-015-0214-7
View details for Web of Science ID 000362397100001
View details for PubMedID 26437964
View details for PubMedCentralID PMC4595320
Liquid chromatography/mass spectrometry methods for measuring dipeptide abundance in non-small-cell lung cancer.
Rapid communications in mass spectrometry : RCM
2013; 27 (18): 2091-2098
Metabolomic profiling is a promising methodology of identifying candidate biomarkers for disease detection and monitoring. Although lung cancer is among the leading causes of cancer-related mortality worldwide, the lung tumor metabolome has not been fully characterized.We utilized a targeted metabolomic approach to analyze discrete groups of related metabolites. We adopted a dansyl [5-(dimethylamino)-1-naphthalene sulfonamide] derivatization with liquid chromatography/mass spectrometry (LC/MS) to analyze changes of metabolites from paired tumor and normal lung tissues. Identification of dansylated dipeptides was confirmed with synthetic standards. A systematic analysis of retention times was required to reliably identify isobaric dipeptides. We validated our findings in a separate sample cohort.We produced a database of the LC retention times and MS/MS spectra of 361 dansyl dipeptides. Interpretation of the spectra is presented. Using this standard data, we identified a total of 279 dipeptides in lung tumor tissue. The abundance of 90 dipeptides was selectively increased in lung tumor tissue compared to normal tissue. In a second set of validation tissues, 12 dipeptides were selectively increased.A systematic evaluation of certain metabolite classes in lung tumors may identify promising disease-specific metabolites. Our database of all possible dipeptides will facilitate ongoing translational applications of metabolomic profiling as it relates to lung cancer. Copyright © 2013 John Wiley & Sons, Ltd.
View details for DOI 10.1002/rcm.6656
View details for PubMedID 23943330
Identification of drug targets by chemogenomic and metabolomic profiling in yeast
PHARMACOGENETICS AND GENOMICS
2012; 22 (12): 877-886
To advance our understanding of disease biology, the characterization of the molecular target for clinically proven or new drugs is very important. Because of its simplicity and the availability of strains with individual deletions in all of its genes, chemogenomic profiling in yeast has been used to identify drug targets. As measurement of drug-induced changes in cellular metabolites can yield considerable information about the effects of a drug, we investigated whether combining chemogenomic and metabolomic profiling in yeast could improve the characterization of drug targets.We used chemogenomic and metabolomic profiling in yeast to characterize the target for five drugs acting on two biologically important pathways. A novel computational method that uses a curated metabolic network was also developed, and it was used to identify the genes that are likely to be responsible for the metabolomic differences found.The combination of metabolomic and chemogenomic profiling, along with data analyses carried out using a novel computational method, could robustly identify the enzymes targeted by five drugs. Moreover, this novel computational method has the potential to identify genes that are causative of metabolomic differences or drug targets.
View details for DOI 10.1097/FPC.0b013e32835aa888
View details for Web of Science ID 000311031800006
View details for PubMedID 23076370