Research Focus
Stem cells persist throughout life in our tissues by undergoing self-renewing divisions in which stem cells divide to form more stem cells. Research from our laboratory and others suggests that many cancers arise from the inappropriate activation of these self-renewal mechanisms, causing cells to proliferate out of control.
Our goal is to better understand the mechanisms that maintain adult tissues and how cancer cells hijack these mechanisms to enable the formation of tumors. To do this, we compare the processes by which stem cells and cancer cells replicate themselves. A better understanding of these mechanisms offers the potential for new regenerative medicine and cancer therapies. By promoting these mechanisms in the context of tissue injury, we can stimulate regeneration. By inhibiting these mechanisms in the context of cancer, we hope to develop anticancer therapies.
Research Projects
Stem Cell Self-Renewal
Stem Cell Aging
Cancer Progression
Stem Cell Self-Renewal
We study the cell-intrinsic and cell-extrinsic mechanisms that regulate stem cell self-renewal and the roles these mechanisms play in tissue homeostasis and cancer. The maintenance of many adult tissues depends on the persistence of stem cells throughout life. Stem cells are maintained in adult tissues by self-renewal, the process by which stem cells divide to make more stem cells. By better understanding this process, we gain insights into how tissues develop and regenerate, how reduced self-renewal can lead to degenerative disease, and how increased self-renewal can lead to tumorigenesis. We identified a series of mechanisms that distinguish stem cell self-renewal from restricted progenitor proliferation as well as self-renewal mechanisms that are conserved among stem cells in different tissues. We are currently focused on areas of cellular physiology that are understudied in stem cells, including metabolism and proteostasis.
We focus on hematopoietic stem cells (HSCs) and the specialized microenvironments, or niches, in which they reside. We identified the location and cellular composition of the HSC niche in bone marrow, including the Leptin Receptor+ (LepR+) stromal cells that are the major source of factors for HSC maintenance. These LepR+ cells also include the skeletal stem cells that are the main source of new osteoblasts and adipocytes in adult bone marrow. We discovered bone-forming growth factors that are produced by the LepR+ cells and that maintain and repair the adult skeleton. LepR+ cells also give rise to osteogenic and adipogenic progenitors that create niches for hematopoietic stem and progenitor cells. We also identified the HSC niche for extramedullary hematopoiesis in the spleen that is activated when the bone marrow is damaged by chemotherapy, radiation, or cancer. This is an exciting time in niche biology as we now have the possibility of going beyond growth factors to ask what other mechanisms niches use to regulate stem and progenitor cell function. Recent studies from our lab have identified metabolic and mechanical regulation.
Stem Cell Aging
Much of age-related morbidity in mammals may be determined by the influence of aging on stem cell function. We have found that stem cells from the hematopoietic and nervous systems undergo strikingly conserved changes in their properties as they age, including declining self-renewal capacity.
We have identified a network of heterochronic gene products that regulates stem cell maintenance throughout life while also regulating the temporal changes in stem cell properties required to match the changing growth and regeneration demands of fetal and adult tissues. Proto-oncogenic signals dominate during fetal development when tissue growth is rapid but cancer risk is low, and tumor-suppressor mechanisms are amplified during aging when there is little tissue growth but cancer risk is high. The increase in tumor suppressor expression during aging delays the development of cancer but also impairs stem cell function and tissue regenerative capacity.
Cancer Progression
Cancer cells hijack stem cell self-renewal mechanisms by acquiring mutations that over-activate these pathways. By comparing the mechanisms that regulate the self-renewal of normal stem cells and the self-replication of cancer cells, we identify differences that represent potential vulnerabilities that can be targeted to kill cancer cells.
We are particularly interested in the mechanisms that regulate melanoma metastasis. We discovered that the survival of melanoma cells during metastasis is limited by oxidative stress. The rare cells that survive metastasis appear to undergo metabolic changes that enhance oxidative stress resistance. By better understanding these mechanisms, we hope to develop pro-oxidant therapies that inhibit cancer progression by exacerbating the oxidative stress experienced by cancer cells.
Cancer cells, including melanoma, often metastasize regionally through lymphatics before metastasizing systemically through the blood. We found that melanoma cells in lymph experience less oxidative stress and form more metastases than melanoma cells in the blood. This is true in both patient-derived melanomas in immunocompromised mice and mouse melanomas in syngeneic, immunocompetent mice. Cells metastasizing through blood, but not lymph, appear to undergo ferroptosis, a form of cell death marked by lipid oxidation. Multiple differences between lymph and blood may contribute to this difference in oxidative stress, including higher levels of oleic acid in lymph. Oleic acid is a monounsaturated fatty acid that can protect cancer cells from ferroptosis by reducing the abundance of oxidizable polyunsaturated fatty acids in phospholipids. We found it is incorporated by melanoma cells in lymph and promotes their survival in the blood. This offers a potential explanation for a clinical behavior that is the basis for much of cancer staging and treatment—the tendency of melanomas and epithelial cancers to metastasize first through lymphatics and then through the blood.
About Dr. Morrison
Sean J. Morrison is the director of the Children’s Medical Center Research Institute at UT Southwestern (CRI) and a Howard Hughes Medical Institute investigator. He holds the Mary McDermott Cook Chair in Pediatric Genetics and the Kathryne and Gene Bishop Distinguished Chair in Pediatric Research. Dr. Morrison completed a B.Sc. in biology and chemistry at Dalhousie University (1991), a Ph.D. in immunology at Stanford University (1996), and a postdoctoral fellowship in neurobiology at Caltech (1999). From 1999 to 2011, Dr. Morrison was a professor at the University of Michigan, where he directed its Center for Stem Cell Biology.
Among other awards, Dr. Morrison received the Presidential Early Career Award for Scientists and Engineers (2003) and a MERIT Award from the National Institute on Aging (2009). He is a member of the National Academy of Medicine (2018) and the National Academy of Sciences (2020). Dr. Morrison served as the President of the International Society for Stem Cell Research (2015–2016) and has been active in public policy issues surrounding stem cell research, testifying before the U.S. Congress, and serving as a leader in the successful “Proposal 2” campaign to protect and regulate stem cell research in Michigan’s state constitution.
Dozens of graduate students and postdoctoral fellows who trained in the Morrison laboratory have gone on to independent academic faculty positions, while others have taken leadership roles in private research institutes or biotechnology companies. In 2020, Dr. Morrison received the Excellence in Postdoctoral Mentoring Award from the UT Southwestern Postdoctoral Association.
Selected Publications
2021
Shen, B., A. Tasdogan, J.M. Ubellacker, J. Zhang, E.D. Nosyreva, L. Du, M.M. Murphy, S. Hu, Y. Yi, N. Kara, X. Liu, S. Guela, Y. Jia, V. Ramesh, C. Embree, E.C. Mitchell, Y.C. Zhao, L.A. Ju, H. Zhao, G.M. Crane, Z. Zhao, R. Syeda, and S.J. Morrison. (2021). A mechanosensitive peri-arteriolar niche for osteogenesis and lymphopoiesis. Nature 591:438-444. (PubMed)
2020
Ubellacker, J.M., A. Tasdogan, V. Ramesh, B. Shen, E.C. Mitchell, M.S. Martin, M.L. McCormick, A.B. Durham, D.R. Spitz, Z. Zhao, T.P. Mathews, and S.J. Morrison. (2020). Lymph protects metastasizing melanoma cells from ferroptosis. Nature 585:113-118. (PubMed)
Tasdogan, A., Faubert, B., Ramesh, V., Ubellacker, J.M., Shen, B., Solmonson, A., Murphy, M.M., Gu, Z., Gu, W., Martin, M., Kasitinon, S.Y., Vandergriff, T., Mathews, T.P., Zhao, Z., Schadendorf, D., DeBerardinis, R.J., and Morrison, S.J. (2020). Metabolic heterogeneity confers differences in melanoma metastatic potential. Nature 577, 115-120. (PubMed)
2019
Shen, B., Vardy, K., Hughes, P., Tasdogan, A., Zhao, Z., Yue, R., Crane, G.M., and Morrison, S.J. (2019). Integrin alpha11 is an Osteolectin receptor and is required for the maintenance of adult skeletal bone mass. eLife, pii: e42274. (PubMed)
2018
Comazzetto, S., Murphy, M.M., Berto, S., Jeffery, E., Zhao, Z., and Morrison, S.J. (2018). Restricted Hematopoietic Progenitors and Erythropoiesis Require SCF from Leptin Receptor+ Niche Cells in the Bone Marrow. Cell Stem Cell, 24, 477-486. (PubMed)
2017
Agathocleous, M., Meecham, C.E., Burgess, R.J., Piskounova, E., Zhao, Z., Crane, G.M., Cowin, B.L., Bruner, E., Murphy, M.M., Chen, W., Spangrude, G.J., Hu, Z., DeBerardinis, R.J., and Morrison, S.J. (2017). Ascorbate regulates haematopoietic stem cell function and leukaemogenesis. Nature 549, 476-481. (PubMed)
2016
Yue, R., Zhou, B.O., and Morrison, S.J. (2016). Clec11a/osteolectin is an osteogenic growth factor that promotes the maintenance of the adult skeleton. eLife, pii:e18782. (PubMed)
2015
Acar, M., Kocherlakota, K.S., Murphy, M.M., Peyer, J.G., Oguro, H., Inra, C.N., Jaiyeola, C.J., Zhao, Z., Luby-Phelps, K., and Morrison, S.J. (2015). Deep imaging of bone marrow shows non-dividing stem cells are mainly perisinusoidal. Nature 526, 126-130. (PubMed)
Piskounova, E., Agathocleous, M., Murphy, M.M., Hu, Z., Mann, S., Zhao, Z., Leitch, A.M., Johnson, T.M., DeBerardinis, R.J., and Morrison, S.J. (2015). Oxidative stress inhibits distant metastasis by human melanoma cells. Nature 527, 186-191. (PubMed)
Inra, C., Zhou, B.O., Acar, M., Murphy, M.M., Zhao, Z., and Morrison, S.J. (2015). A perisinusoidal niche for extramedullary hematopoiesis in the spleen. Nature 527, 466-471. (PubMed)
2014
Zhou, B.O., Yue, R., Murphy, M.M., Peyer, J.G., and Morrison, S.J. (2014). Leptin-receptor-expressing mesenchymal stromal cells represent the main source of bone formed by adult bone marrow. Cell Stem Cell 15, 154-168. (PubMed)
Signer, R.A.J., Magee, J.A., Salic, A., and Morrison, S.J. (2014). Haematopoietic stem cells require a highly regulate protein synthesis rate. Nature 509, 49-54. (PubMed)
Nakada, D., Oguro, H., Levi, B., Ryan, N., Kitano, A., Saitoh, Y., Takeichi, M., Wendt, G., and Morrison, S.J. (2014). Oestrogen increases haematopoietic stem-cell self-renewal in females and during pregnancy. Nature 505, 555-558. (PubMed)
Morrison, S.J., and Scadden, D.T. (2014). The bone marrow niche for haematopoietic stem cells. Nature 505, 327-334. (PubMed)
2013
Li, Q., Bohin, N., Wen, T., Ng, V., Magee, J., Chen, S.C., Shannon, K., and Morrison, S.J. (2013). Oncogenic Nras has bimodal effects on stem cells that sustainably increase competitiveness. Nature 504, 143-147. (PubMed)
Meacham, C.E., and Morrison, S.J. (2013). Tumor heterogeneity and cancer cell plasticity. Nature 501, 328-337. (PubMed)
Ding, L., and Morrison, S.J. (2013). Haematopoietic stem cells and early lymphoid progenitors occupy distinct bone marrow niches. Nature 495, 231-235. (PubMed)
2012
Ding, L., Saunders, T.L., Enikolopov, G., and Morrison, S.J. (2012). Endothelial and perivascular cells maintain hematopoietic stem cells. Nature 481, 457-462. (PubMed)
2010
Nakada, D., Saunders, T.L., and Morrison, S.J. (2010). Lkb1 regulates cell cycle and energy metabolism in haematopoietic stem cells. Nature 468, 653-658. (PubMed)
Chuikov, S., Levi, B.P., Smith, M.L., and Morrison, S.J. (2010). Prdm16 promotes stem cell maintenance in multiple tissues, partly by regulating oxidative stress. Nat Cell Biol 12, 999-1006. (PubMed)
2009
Shackleton, M., Quintana, E., Fearon, E., and Morrison, S.J. (2009). Heterogeneity in cancer: cancer stem cells versus clonal evolution. Cell 138, 822-829. (PubMed)
2008
Quintana, E., Shackleton, M., Sabel, M., Fullen, D., Johnson, T.M., and Morrison, S.J. (2008). Efficient tumor formation by single human melanoma cells. Nature 456, 593-598. (PubMed)
Nishino, J., Kim, I., Chada, K., and Morrison, S.J. (2008). Hmga2 promotes neural stem cell self-renewal in young, but not old, mice by reducing p16 Ink4a and p19Arf expression. Cell 135, 227-239. (PubMed)
Morrison, S.J., and Spradling, A. (2008). Stem Cells and Niches: Mechanisms that promote stem cell maintenance throughout life. Cell 132, 598-611. (PubMed)
2007
Kiel, M.J., He, S., Ashkenazi, R., Gentry, S.N., Teta, M., Kushner, J.A., Jackson, T.L., and Morrison, S.J. (2007). Hematopoietic stem cells do not asymmetrically segregate chromosomes or retain bromodeoxyuridine. Nature 449, 238-242. (PubMed)
Kim, I., Saunders, T.L., and Morrison, S.J. (2007). Sox17 dependence distinguishes the transcriptional regulation of fetal from adult hematopoietic stem cells. Cell 130, 470-483. (PubMed)
2006
Molofsky, A.V., Slutsky, S.G., Joseph, N.M., He, S., Pardal, R., Krishnamurthy, J., Sharpless, N., and Morrison, S.J. (2006). Increasing p16 Ink4a expression decreases forebrain progenitor function and neurogenesis during ageing. Nature 443, 448-452. (PubMed)
Morrison, S.J., and Kimble, J. (2006). Asymmetric and symmetric stem-cell divisions in development and cancer. Nature 441, 1068-1074. (PubMed)
Yilmaz, O.H., Valdez, R., Theisen, B., Guo, W., Ferguson, D., Wu, H., and Morrison, S.J. (2006). Pten dependence distinguishes haematopoietic stem cells from leukaemia-initiating cells. Nature 441, 475-482. (PubMed)
2005
Kiel, M.J., Yilmaz, O.H., Iwashita, T., Terhorst, C., and Morrison, S.J. (2005). SLAM family receptors distinguish hematopoietic stem and progenitor cells and reveal endothelial niches for stem cells. Cell 121, 1109-1121. (PubMed)
2003
Molofsky, A.V., Pardal, R., Iwashita, T., Park, I.K., Clarke, M.F., and Morrison, S.J. (2003). Bmi-1 dependence distinguishes neural stem cell self-renewal from progenitor proliferation. Nature 425, 962-967. (PubMed)
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Lab News
Sean Morrison Presented with Excellence in Postdoctoral Mentoring Award
September 23, 2020UT Southwestern’s Postdoctoral Association (PDA) has selected Dr. Sean Morrison, director of Children’s Medical Center Research Institute at UT Southwestern…
The secret of lymph: How lymph nodes help cancer cells spread
August 19, 2020August 19, 2020 – For decades, physicians have known that many kinds of cancer cells often spread first to lymph nodes…
Lab Members
Liming Du, Ph.D.
Postdoctoral Fellow
Michalis Agathocleous, Ph.D.
Assistant Professor, Children’s Medical Center Research Institute at UT Southwestern
Postdoctoral Fellow (2011-2017)
Kati Ahlqvist, Ph.D.
Human Frontier Postdoctoral Fellow, Pekka Katajisto Laboratory, University of Helsinki
Postdoctoral Fellow (2016-2018)
Johanna Buchstaller, Ph.D.
Data Scientist, Vienna University of Technology, Austria
Postdoctoral Fellow (2004-2011)
Genevieve Crane, M.D., Ph.D.
Staff Hematopathologist, Cleveland Clinic
UM Medical Scientist Training Program (2000-2004)
Lei Ding, Ph.D.
Assistant Professor, Department of Regeneration and Rehabilitative Medicine, Columbia University
Postdoctoral Fellow (2007-2013)
Ugur Eskiocak, Ph.D.
Senior Director, Translational Sciences, Janux Therapeutics
Postdoctoral Fellow (2011-2016)
Jennifer Gill, M.D., Ph.D.
Assistant Professor, Department of Dermatology, UT Southwestern Medical Center
Clinical Fellow (2015-2020)
Shenghui He, Ph.D.
Assistant Professor, Genetics, University of North Carolina
UM Cellular and Molecular Biology Program (2004-2013)
Christopher Inra, M.D., Ph.D.
Assistant Professor, Medicine, Johns Hopkins University
UTSW Medical Scientist Training Program (2010-2015)
Toshihide Iwashita, Ph.D.
Professor, Hamamatsu University School of Medicine, Japan
Postdoctoral Fellow (2000-2005)
Nancy Joseph, M.D., Ph.D.
Associate Professor of Pathology & Associate Director of Clinical Cancer Genomics Laboratory, UCSF
UM Medical Scientist Training Program (2001-2006)
Mark Kiel, M.D., Ph.D.
Chief Scientific Officer at GENOMENON
UM Medical Scientist Training Program (2002-2008)
Injune Kim, Ph.D.
Associate Professor, Korea Advanced Institute of Science and Technology
Postdoctoral Fellow (2002-2008)
Jae Lee, M.D., Ph.D.
Radiation Oncologist, Princeton Radiation Oncology, NJ
UM Medical Scientist Training Program (2006-2010)
Boaz Levi, Ph.D.
Associate Investigator, Human Cell Types, Allen Institute for Brain Research, Seattle
Postdoctoral Fellow (2006-2011)
Qing Li, Ph.D.
Associate Professor of Internal Medicine, University of Michigan
Postdoctoral Fellow (2009-2011)
Jeffrey Magee, M.D.
Associate Professor of Pediatrics, Washington University
Pediatrics Fellow (2008-2013)
John Mich, Ph.D.
Senior Scientist, Allen Institute for Brain Research
Postdoctoral Fellow (2010-2015)
Anna Molofsky, M.D., Ph.D.
Associate Professor of Psychiatry, University of California at San Francisco
UM Medical Scientist Training Program (2001-2005)
Jack Mosher, Ph.D.
Scientific Affairs Manager, International Society for Stem Cell Research
Postdoctoral Fellow (2001-2006)
Malea Murphy, Ph.D.
Manager Integrated Microscopy & Imaging Laboratory Medical Physiology, Texas A&M University College of Medicine
Postdoctoral Fellow (2012-2019)
Daisuke Nakada, M.D., Ph.D.
Associate Professor, Department of Molecular and Human Genetics, Baylor College of Medicine
Postdoctoral Fellow (2006-2011)
Hideyuki Oguro, Ph.D.
Assistant Professor, Cell Biology, University of Connecticut Health Center
Postdoctoral Fellow (2009 - 2017)
Ricardo Pardal, Ph.D.
Professor, University of Seville, Spain
Postdoctoral Fellow (2001-2004)
Michel Perron, Ph.D.
Senior Research Scientist, Gilead
Postdoctoral Fellow (2007-2008)
James Peyer, Ph.D.
CEO and Co-Founder, Cambrian BioPharma
UTSW Genetics and Development Graduate Program (2010-2015)
Elena Piskounova, Ph.D
Assistant Professor of Dermatology, Weill Cornell Medical College
Postdoctoral Fellow (2011-2017)
Le Qi , Ph.D.
Postdoctoral Fellow, Dan Geschwind Lab, University of California, Los Angeles
UTSW Cancer Biology (2014 -2021)
Elsa Quintana, Ph.D.
Director, Revolution Medicines
Postdoctoral Fellow (2005-2011)
Mick Savona, Ph.D.
Professor of Medicine and Cancer Biology, Director of Hematology Early Therapeutics Program, Vanderbilt University, Nashville
Postdoctoral Fellow (2006-2008)
Mark Shackleton, Ph.D.
Director of Oncology, Alfred Health and Professor of Oncology, Monash University (Melbourne, Australia)
Postdoctoral Fellow (2006-2009)
Issei Shimada, Ph.D.
Junior Associate Professor, Department of Cell Biology, Graduate School of Medicine Sciences, Nagoya City University in Japan
Postdoctoral Fellow (2011-2014)
Robert Signer, Ph.D.
Assistant Professor, University of California at San Diego
Postdoctoral Fellow (2009 - 2015)
Bo Shen, Ph.D.
Assistant Investigator, National Institute of Biological Sciences, Beijing, China
Postdoctoral Fellow (2015-2021)
Shalom Guy Slutsky, Ph.D.
Clinical Trial Manager, Kadimastem Ltd
Postdoctoral Fellow (2005-2007)
Alpaslan Tasdogan, M.D., Ph.D.
Associate Professor, Department of Dermatology, University of Essen-Duisburg and German Cancer Consortium, Essen, Germany
Postdoctoral Fellow (2016-2021)
Merritt Taylor, Ph.D.
Associate Professor, Grand Valley State University
Postdoctoral Fellow (2001-2007)
Jessalyn Ubellacker, Ph.D.
Assistant Professor, Molecular Metabolism, Harvard School of Public Health
Postdoctoral Fellow (2018-2020)
Omer Yilmaz, M.D., Ph.D.
Associate Professor, Koch Institute, Massachusetts Institute of Technology
UM Medical Scientist Training Program (2001-2006)
Stacy Yuan, Ph.D.
Dermatology Residency at UT Southwestern Medical Center
UTSW Medical Scientist Training Program (2014-2019)
Rui Yue, Ph.D.
Professor, Tongji University, Shanghai, China
Postdoctoral Fellow (2011-2017)
Bo Zhou, Ph.D.
Professor, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences
Postdoctoral Fellow (2011-2016)
