Shannon White

All Publications

• Single-cell spatial mapping reveals alteration of cell type composition and tissue microenvironment during early colorectal cancer formation. bioRxiv : the preprint server for biology Guha, T. K., Esplin, E. D., Horning, A. M., Chiu, R., Paul, K., Weimer, A. K., Becker, W. R., Laquindanum, R., Mills, M. A., Glen Esplin, D., Shen, J., Monte, E., White, S., Karathanos, T. V., Cotter, D., Bi, J., Ladabaum, U., Longacre, T. A., Curtis, C., Greenleaf, W. J., Ford, J. M., Snyder, M. P. 2024

  Abstract

  Colorectal cancer (CRC) is the third leading cause of cancer mortality in the United States. Familial adenomatous polyposis (FAP) is a hereditary syndrome that raises the risk of developing CRC, with total colectomy as the only effective prevention. Even though FAP is rare (0.5% of all CRC cases), this disease model is well suited for studying the early stages of malignant transformation as patients form many polyps reflective of pre-cancer states. In order to spatially profile and analyze the pre-cancer and tumor microenvironment, we have performed single-cell multiplexed imaging for 52 samples: 12 normal mucosa,16 FAP mucosa,18 FAP polyps, 2 FAP adenocarcinoma, and 4 sporadic colorectal cancer (CRCs) using Co-detection by Indexing (CODEX) imaging platform. The data revealed significant changes in cell type composition occurring in early stage polyps and during the malignant transformation of polyps to CRC. We observe a decrease in CD4+/CD8+ T cell ratio and M1/M2 macrophage ratio along the FAP disease continuum. Advanced dysplastic polyps show a higher population of cancer associated fibroblasts (CAFs), which likely alter the pre-cancer microenvironment. Within polyps and CRCs, we observe strong nuclear expression of beta-catenin and higher number neo-angiogenesis events, unlike FAP mucosa and normal colon counterparts. We identify an increase in cancer stem cells (CSCs) within the glandular crypts of the FAP polyps and also detect Tregs, tumor associated macrophages (TAMs) and vascular endothelial cells supporting CSC survival and proliferation. We detect a potential immunosuppressive microenvironment within the tumor 'nest' of FAP adenocarcinoma samples, where tumor cells tend to segregate and remain distant from the invading immune cells. TAMs were found to infiltrate the tumor area, along with angiogenesis and tumor proliferation. CAFs were found to be enriched near the inflammatory region within polyps and CRCs and may have several roles in supporting tumor growth. Neighborhood analyses between adjacent FAP mucosa and FAP polyps show significant differences in spatial location of cells based on functionality. For example, in FAP mucosa, naive CD4+ T cells alone tend to localize near the fibroblast within the stromal compartment. However, in FAP polyp, CD4+T cells colocalize with the macrophages for T cell activation. Our data are expected to serve as a useful resource for understanding the early stages of neogenesis and the pre-cancer microenvironment, which may benefit early detection, therapeutic intervention and future prevention.

  View details for DOI 10.1101/2024.11.20.622725

  View details for PubMedID 39605357

• Global loss of promoter-enhancer connectivity and rebalancing of gene expression during early colorectal cancer carcinogenesis. Nature cancer Zhu, Y., Lee, H., White, S., Weimer, A. K., Monte, E., Horning, A., Nevins, S. A., Esplin, E. D., Paul, K., Krieger, G., Shipony, Z., Chiu, R., Laquindanum, R., Karathanos, T. V., Chua, M. W., Mills, M., Ladabaum, U., Longacre, T., Shen, J., Jaimovich, A., Lipson, D., Kundaje, A., Greenleaf, W. J., Curtis, C., Ford, J. M., Snyder, M. P. 2024

  Abstract

  Although three-dimensional (3D) genome architecture is crucial for gene regulation, its role in disease remains elusive. We traced the evolution and malignant transformation of colorectal cancer (CRC) by generating high-resolution chromatin conformation maps of 33 colon samples spanning different stages of early neoplastic growth in persons with familial adenomatous polyposis (FAP). Our analysis revealed a substantial progressive loss of genome-wide cis-regulatory connectivity at early malignancy stages, correlating with nonlinear gene regulation effects. Genes with high promoter-enhancer (P-E) connectivity in unaffected mucosa were not linked to elevated baseline expression but tended to be upregulated in advanced stages. Inhibiting highly connected promoters preferentially represses gene expression in CRC cells compared to normal colonic epithelial cells. Our results suggest a two-phase model whereby neoplastic transformation reduces P-E connectivity from a redundant state to a rate-limiting one for transcriptional levels, highlighting the intricate interplay between 3D genome architecture and gene regulation during early CRC progression.

  View details for DOI 10.1038/s43018-024-00823-z

  View details for PubMedID 39478119

  View details for PubMedCentralID 7541718

• Recurrent repeat expansions in human cancer genomes. Nature Erwin, G. S., Gursoy, G., Al-Abri, R., Suriyaprakash, A., Dolzhenko, E., Zhu, K., Hoerner, C. R., White, S. M., Ramirez, L., Vadlakonda, A., Vadlakonda, A., von Kraut, K., Park, J., Brannon, C. M., Sumano, D. A., Kirtikar, R. A., Erwin, A. A., Metzner, T. J., Yuen, R. K., Fan, A. C., Leppert, J. T., Eberle, M. A., Gerstein, M., Snyder, M. P. 2022

  Abstract

  Expansion of a single repetitive DNA sequence, termed a tandem repeat (TR), is known to cause more than 50 diseases1,2. However, repeat expansions are often not explored beyond neurological and neurodegenerative disorders. In some cancers, mutations accumulate in short tracts of TRs, a phenomenon termed microsatellite instability; however, larger repeat expansions have not been systematically analysed in cancer3-8. Here we identified TR expansions in 2,622 cancer genomes spanning 29 cancer types. In seven cancer types, we found 160 recurrent repeat expansions (rREs), most of which (155/160) were subtype specific. We found that rREs were non-uniformly distributed in the genome with enrichment near candidate cis-regulatory elements, suggesting a potential role in gene regulation. One rRE, a GAAA-repeat expansion, located near a regulatory element in the first intron of UGT2B7 was detected in 34% of renal cell carcinoma samples and was validated by long-read DNA sequencing. Moreover, in preliminary experiments, treating cells that harbour this rRE with a GAAA-targeting molecule led to a dose-dependent decrease in cell proliferation. Overall, our results suggest that rREs may be an important but unexplored source of genetic variation in human cancer, and we provide a comprehensive catalogue for further study.

  View details for DOI 10.1038/s41586-022-05515-1

  View details for PubMedID 36517591

• MITI minimum information guidelines for highly multiplexed tissue images. Nature methods Schapiro, D., Yapp, C., Sokolov, A., Reynolds, S. M., Chen, Y., Sudar, D., Xie, Y., Muhlich, J., Arias-Camison, R., Arena, S., Taylor, A. J., Nikolov, M., Tyler, M., Lin, J., Burlingame, E. A., Human Tumor Atlas Network, Chang, Y. H., Farhi, S. L., Thorsson, V., Venkatamohan, N., Drewes, J. L., Pe'er, D., Gutman, D. A., Herrmann, M. D., Gehlenborg, N., Bankhead, P., Roland, J. T., Herndon, J. M., Snyder, M. P., Angelo, M., Nolan, G., Swedlow, J. R., Schultz, N., Merrick, D. T., Mazzili, S. A., Cerami, E., Rodig, S. J., Santagata, S., Sorger, P. K., Abravanel, D. L., Achilefu, S., Ademuyiwa, F. O., Adey, A. C., Aft, R., Ahn, K. J., Alikarami, F., Alon, S., Ashenberg, O., Baker, E., Baker, G. J., Bandyopadhyay, S., Bayguinov, P., Beane, J., Becker, W., Bernt, K., Betts, C. B., Bletz, J., Blosser, T., Boire, A., Boland, G. M., Boyden, E. S., Bucher, E., Bueno, R., Cai, Q., Cambuli, F., Campbell, J., Cao, S., Caravan, W., Chaligne, R., Chan, J. M., Chasnoff, S., Chatterjee, D., Chen, A. A., Chen, C., Chen, C., Chen, B., Chen, F., Chen, S., Chheda, M. G., Chin, K., Cho, H., Chun, J., Cisneros, L., Coffey, R. J., Cohen, O., Colditz, G. A., Cole, K. A., Collins, N., Cotter, D., Coussens, L. M., Coy, S., Creason, A. L., Cui, Y., Zhou, D. C., Curtis, C., Davies, S. R., Bruijn, I., Delorey, T. M., Demir, E., Denardo, D., Diep, D., Ding, L., DiPersio, J., Dubinett, S. M., Eberlein, T. J., Eddy, J. A., Esplin, E. D., Factor, R. E., Fatahalian, K., Feiler, H. S., Fernandez, J., Fields, A., Fields, R. C., Fitzpatrick, J. A., Ford, J. M., Franklin, J., Fulton, B., Gaglia, G., Galdieri, L., Ganesh, K., Gao, J., Gaudio, B. L., Getz, G., Gibbs, D. L., Gillanders, W. E., Goecks, J., Goodwin, D., Gray, J. W., Greenleaf, W., Grimm, L. J., Gu, Q., Guerriero, J. L., Guha, T., Guimaraes, A. R., Gutierrez, B., Hacohen, N., Hanson, C. R., Harris, C. R., Hawkins, W. G., Heiser, C. N., Hoffer, J., Hollmann, T. J., Hsieh, J. J., Huang, J., Hunger, S. P., Hwang, E., Iacobuzio-Donahue, C., Iglesia, M. D., Islam, M., Izar, B., Jacobson, C. A., Janes, S., Jayasinghe, R. G., Jeudi, T., Johnson, B. E., Johnson, B. E., Ju, T., Kadara, H., Karnoub, E., Karpova, A., Khan, A., Kibbe, W., Kim, A. H., King, L. M., Kozlowski, E., Krishnamoorthy, P., Krueger, R., Kundaje, A., Ladabaum, U., Laquindanum, R., Lau, C., Lau, K. S., LeBoeuf, N. R., Lee, H., Lenburg, M., Leshchiner, I., Levy, R., Li, Y., Lian, C. G., Liang, W., Lim, K., Lin, Y., Liu, D., Liu, Q., Liu, R., Lo, J., Lo, P., Longabaugh, W. J., Longacre, T., Luckett, K., Ma, C., Maher, C., Maier, A., Makowski, D., Maley, C., Maliga, Z., Manoj, P., Maris, J. M., Markham, N., Marks, J. R., Martinez, D., Mashl, J., Masilionis, I., Massague, J., Mazurowski, M. A., McKinley, E. T., McMichael, J., Meyerson, M., Mills, G. B., Mitri, Z. I., Moorman, A., Mudd, J., Murphy, G. F., Deen, N. N., Navin, N. E., Nawy, T., Ness, R. M., Nevins, S., Nirmal, A. J., Novikov, E., Oh, S. T., Oldridge, D. A., Owzar, K., Pant, S. M., Park, W., Patti, G. J., Paul, K., Pelletier, R., Persson, D., Petty, C., Pfister, H., Polyak, K., Puram, S. V., Qiu, Q., Villalonga, A. Q., Ramirez, M. A., Rashid, R., Reeb, A. N., Reid, M. E., Remsik, J., Riesterer, J. L., Risom, T., Ritch, C. C., Rolong, A., Rudin, C. M., Ryser, M. D., Sato, K., Sears, C. L., Semenov, Y. R., Shen, J., Shoghi, K. I., Shrubsole, M. J., Shyr, Y., Sibley, A. B., Simmons, A. J., Sinha, A., Sivagnanam, S., Song, S., Southar-Smith, A., Spira, A. E., Cyr, J. S., Stefankiewicz, S., Storrs, E. P., Stover, E. H., Strand, S. H., Straub, C., Street, C., Su, T., Surrey, L. F., Suver, C., Tan, K., Terekhanova, N. V., Ternes, L., Thadi, A., Thomas, G., Tibshirani, R., Umeda, S., Uzun, Y., Vallius, T., Van Allen, E. R., Vandekar, S., Vega, P. N., Veis, D. J., Vennam, S., Verma, A., Vigneau, S., Wagle, N., Wahl, R., Walle, T., Wang, L., Warchol, S., Washington, M. K., Watson, C., Weimer, A. K., Wendl, M. C., West, R. B., White, S., Windon, A. L., Wu, H., Wu, C., Wu, Y., Wyczalkowski, M. A., Xu, J., Yao, L., Yu, W., Zhang, K., Zhu, X. 2022; 19 (3): 262-267

  View details for DOI 10.1038/s41592-022-01415-4

  View details for PubMedID 35277708

• Master lineage transcription factors anchor trans mega transcriptional complexes at highly accessible enhancer sites to promote long-range chromatin clustering and transcription of distal target genes. Nucleic acids research White, S. M., Snyder, M. P., Yi, C. 2021

  Abstract

  The term 'super enhancers' (SE) has been widely used to describe stretches of closely localized enhancers that are occupied collectively by large numbers of transcription factors (TFs) and co-factors, and control the transcription of highly-expressed genes. Through integrated analysis of >600 DNase-seq, ChIP-seq, GRO-seq, STARR-seq, RNA-seq, Hi-C and ChIA-PET data in five human cancer cell lines, we identified a new class of autonomous SEs (aSEs) that are excluded from classic SE calls by the widely used Rank Ordering of Super-Enhancers (ROSE) method. TF footprint analysis revealed that compared to classic SEs and regular enhancers, aSEs are tightly bound by a dense array of master lineage TFs, which serve as anchors to recruit additional TFs and co-factors in trans. In addition, aSEs are preferentially enriched for Cohesins, which likely involve in stabilizing long-distance interactions between aSEs and their distal target genes. Finally, we showed that aSEs can be reliably predicted using a single DNase-seq data or combined with Mediator and/or P300 ChIP-seq. Overall, our study demonstrates that aSEs represent a unique class of functionally important enhancer elements that distally regulate the transcription of highly expressed genes.

  View details for DOI 10.1093/nar/gkab1105

  View details for PubMedID 34850122

• A Yap-Myc-Sox2-p53 Regulatory Network Dictates Metabolic Homeostasis and Differentiation in Kras-Driven Pancreatic Ductal Adenocarcinomas DEVELOPMENTAL CELL Murakami, S., Nemazanyy, I., White, S. M., Chen, H., Nguyen, C. K., Graham, G. T., Saur, D., Pende, M., Yi, C. 2019; 51 (1): 113-+

  Abstract

  Employing inducible genetically engineered and orthotopic mouse models, we demonstrate a key role for transcriptional regulator Yap in maintenance of Kras-mutant pancreatic tumors. Integrated transcriptional and metabolomics analysis reveals that Yap transcribes Myc and cooperates with Myc to maintain global transcription of metabolic genes. Yap loss triggers acute metabolic stress, which causes tumor regression while inducing epigenetic reprogramming and Sox2 upregulation in a subset of pancreatic neoplastic cells. Sox2 restores Myc expression and metabolic homeostasis in Yap-deficient neoplastic ductal cells, which gradually re-differentiate into acinar-like cells, partially restoring pancreatic parenchyma in vivo. Both the short-term and long-term effects of Yap loss in inducing cell death and re-differentiation, respectively, are blunted in advanced, poorly differentiated p53-mutant pancreatic tumors. Collectively, these findings reveal a highly dynamic and interdependent metabolic, transcriptional, and epigenetic regulatory network governed by Yap, Myc, Sox2, and p53 that dictates pancreatic tumor metabolism, growth, survival, and differentiation.

  View details for DOI 10.1016/j.devcel.2019.07.022

  View details for Web of Science ID 000489167900012

  View details for PubMedID 31447265

  View details for PubMedCentralID PMC6783361

• YAP/TAZ Inhibition Induces Metabolic and Signaling Rewiring Resulting in Targetable Vulnerabilities in NF2-Deficient Tumor Cells DEVELOPMENTAL CELL White, S. M., Avantaggiati, M., Nemazanyy, I., Di Poto, C., Yang, Y., Pende, M., Gibney, G. T., Ressom, H. W., Field, J., Atkins, M. B., Yi, C. 2019; 49 (3): 425-+

  Abstract

  Merlin/NF2 is a bona fide tumor suppressor whose mutations underlie inherited tumor syndrome neurofibromatosis type 2 (NF2), as well as various sporadic cancers including kidney cancer. Multiple Merlin/NF2 effector pathways including the Hippo-YAP/TAZ pathway have been identified. However, the molecular mechanisms underpinning the growth and survival of NF2-mutant tumors remain poorly understood. Using an inducible orthotopic kidney tumor model, we demonstrate that YAP/TAZ silencing is sufficient to induce regression of pre-established NF2-deficient tumors. Mechanistically, YAP/TAZ depletion diminishes glycolysis-dependent growth and increases mitochondrial respiration and reactive oxygen species (ROS) buildup, resulting in oxidative-stress-induced cell death when challenged by nutrient stress. Furthermore, we identify lysosome-mediated cAMP-PKA/EPAC-dependent activation of RAF-MEK-ERK signaling as a resistance mechanism to YAP/TAZ inhibition. Finally, unbiased analysis of TCGA primary kidney tumor transcriptomes confirms a positive correlation of a YAP/TAZ signature with glycolysis and inverse correlations with oxidative phosphorylation and lysosomal gene expression, supporting the clinical relevance of our findings.

  View details for DOI 10.1016/j.devcel.2019.04.014

  View details for Web of Science ID 000466934100016

  View details for PubMedID 31063758

  View details for PubMedCentralID PMC6524954

• The complex entanglement of Hippo-Yap/Taz signaling in tumor immunity ONCOGENE White, S. M., Murakami, S., Yi, C. 2019; 38 (16): 2899-2909

  Abstract

  The Hippo-Yap/Taz pathway, originally identified as a central developmental regulator of organ size, has been found perturbed in many types of human tumors, and linked to tumor growth, survival, evasion, metastasis, stemness, and drug resistance. Beside these tumor-cell-intrinsic functions, Hippo signaling also plays important immune-regulatory roles. In this review, we will summarize and discuss recent breakthroughs in our understanding of how various components of the Hippo-Yap/Taz pathway influence the tumor immune microenvironment, including their effects on the tumor secretome and immune infiltrates, their roles in regulating crosstalk between tumor cells and T cells, and finally their intrinsic functions in various types of innate and adaptive immune cells. While further research is needed to integrate and reconcile existing findings and to discern the overall effects of Hippo signaling on tumor immunity, it is clear that Hippo signaling functions as a key bridge connecting tumor cells with both the adaptive and innate immune systems. Thus, all future therapeutic development against the Hippo-Yap/Taz pathway should take into account their multi-faceted roles in regulating tumor immunity in addition to their growth-regulatory functions. Given that immune therapies have become the mainstay of cancer treatment, it is also important to pursue how to manipulate Hippo signaling to boost response or overcome resistance to existing immune therapies.

  View details for DOI 10.1038/s41388-018-0649-6

  View details for Web of Science ID 000465167600002

  View details for PubMedID 30617303

  View details for PubMedCentralID PMC7567008

• Rac1-Mediated DNA Damage and Inflammation Promote Nf2 Tumorigenesis but Also Limit Cell-Cycle Progression DEVELOPMENTAL CELL Shi, Y., Bollam, S. R., White, S. M., Laughlin, S. Z., Graham, G. T., Wadhwa, M., Chen, H., Nguyen, C., Vitte, J., Giovannini, M., Toretsky, J., Yi, C. 2016; 39 (4): 452-465

  Abstract

  Merlin encoded by the Nf2 gene is a bona fide tumor suppressor that has been implicated in regulation of both the Hippo-Yap and Rac1-Pak1 pathways. Using genetically engineered murine liver models, we show that co-deletion of Rac1 with Nf2 blocks tumor initiation but paradoxically exacerbates hepatomegaly induced by Nf2 loss, which can be suppressed either by treatment with pro-oxidants or by co-deletion of Yap. Our results suggest that while Yap acts as the central driver of proliferation during Nf2 tumorigenesis, Rac1 primarily functions as an inflammation switch by inducing reactive oxygen species that, on one hand, induce nuclear factor κB signaling and expression of inflammatory cytokines, and on the other activate p53 checkpoint and senescence programs dampening the cyclin D1-pRb-E2F1 pathway. Interestingly, senescence markers are associated with benign NF2 tumors but not with malignant NF2 mutant mesotheliomas, suggesting that senescence may underlie the benign nature of most NF2 tumors.

  View details for DOI 10.1016/j.devcel.2016.09.027

  View details for Web of Science ID 000389162800010

  View details for PubMedID 27818180

  View details for PubMedCentralID PMC5519326

• An ensemble model of QSAR tools for regulatory risk assessment JOURNAL OF CHEMINFORMATICS Pradeep, P., Povinelli, R. J., White, S., Merrill, S. J. 2016; 8: 48

  Abstract

  Quantitative structure activity relationships (QSARs) are theoretical models that relate a quantitative measure of chemical structure to a physical property or a biological effect. QSAR predictions can be used for chemical risk assessment for protection of human and environmental health, which makes them interesting to regulators, especially in the absence of experimental data. For compatibility with regulatory use, QSAR models should be transparent, reproducible and optimized to minimize the number of false negatives. In silico QSAR tools are gaining wide acceptance as a faster alternative to otherwise time-consuming clinical and animal testing methods. However, different QSAR tools often make conflicting predictions for a given chemical and may also vary in their predictive performance across different chemical datasets. In a regulatory context, conflicting predictions raise interpretation, validation and adequacy concerns. To address these concerns, ensemble learning techniques in the machine learning paradigm can be used to integrate predictions from multiple tools. By leveraging various underlying QSAR algorithms and training datasets, the resulting consensus prediction should yield better overall predictive ability. We present a novel ensemble QSAR model using Bayesian classification. The model allows for varying a cut-off parameter that allows for a selection in the desirable trade-off between model sensitivity and specificity. The predictive performance of the ensemble model is compared with four in silico tools (Toxtree, Lazar, OECD Toolbox, and Danish QSAR) to predict carcinogenicity for a dataset of air toxins (332 chemicals) and a subset of the gold carcinogenic potency database (480 chemicals). Leave-one-out cross validation results show that the ensemble model achieves the best trade-off between sensitivity and specificity (accuracy: 83.8 % and 80.4 %, and balanced accuracy: 80.6 % and 80.8 %) and highest inter-rater agreement [kappa (κ): 0.63 and 0.62] for both the datasets. The ROC curves demonstrate the utility of the cut-off feature in the predictive ability of the ensemble model. This feature provides an additional control to the regulators in grading a chemical based on the severity of the toxic endpoint under study.

  View details for DOI 10.1186/s13321-016-0164-0

  View details for Web of Science ID 000383831100001

  View details for PubMedID 28316646

  View details for PubMedCentralID PMC5034616