Michael Clark

Michael Clarke's laboratory is focused on stem cells and cancer. Studies from the Clarke laboratory suggest that only a subset of cancer cells within a tumor, the so-called cancer stem cells, drive growth and metastasis of the tumor. His laboratory has developed methods to identify and isolate this cancer stem cell population from human breast tumors. The presence of a stem cell population in a tumor has important implications for the diagnosis and treatment of cancer, since it is these cells that must be targeted in order to block tumor cell growth. The Clark lab is focused on understanding the pathways that control renewal in normal stem cells and on how these pathways are disrupted in cancer stem cells. Dr. Clarke is Professor of Internal Medicine and holds the Karel and Avice Beekhuis Endowed Professorship in Cancer Biology at Stanford University. He is the Associate Director of the Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford, California.

2006 Symposium Topic: The Dark Side of Stem Cells

Margaret Goodell

Peggy Goodell has had a long-standing interest in understanding how hematopoietic stem cells (HSCs) remain quiescent yet retain the potential for self-renewal and for differentiation once activated. Her studies have identified genes that are induced as the self-renewal program is activated, and her current studies are designed to reveal the role that these genes play in self-renewal. These findings have important clinical implications, as understanding how these genes regulate self-renewal is likely to provide a rational approach for experimentally manipulating and expanding HSCs in vitro, which would greatly facilitate bone marrow transplantation. Moreover, understanding how self-renewal is regulated may provide tools for limiting the growth of certain tumors. Dr. Goodell has also made key contributions to understanding the potential of HSCs to contribute to definitive, differentiated cell types; in this regard, her studies of the potential of HSCs to contribute the skeletal muscle lineage have been among the most incisive and critical experiments in the field. Dr. Goodell is Associate Professor, in the Department of Pediatrics, Molecular and Human Genetics, and Immunology at Baylor College of Medicine in Houston, Texas and is the Director of the Stem Cells and Regenerative Medicine Center at Baylor College of Medicine.

2006 Symposium Topic: Molecular regulation of hematopoietic stem cells

Rudolf Jaenisch

Rudolf Jaenisch is a pioneer of transgenic mouse technology, and was the first to produce a transgenic mouse. His research concentrates on gene regulation, in particular epigenetic changes that occur during development, cancer progression and reprogramming of the genome following cloning by nuclear transfer. His lab has generated an impressive series of mouse mutants in the genes that regulate DNA methylation, a crucial component of epigenetic gene regulation. They have uncovered how loss of DNA methylation contributes to disease states such as cancer, and accounts for the poor survival and overgrowth seen in cloned animals. He has also developed a number of techniques associated with nuclear transfer, including an efficient method for cloning utilizing mouse embryonic stem cells and a âtherapeudic cloning technique. Rudolf Jaenisch is also known for educating the public in genetics and animal cloning. He was a founding member of the Whitehead Institute and is a professor in the Department of Biology at MIT. Among other honors, he is a member of the National Academy of Sciences.

2006 Symposium Topic: Programming and reprogramming of the genome

Gordon Keller

Gordon Keller is a leading expert in studying how embryonic stem cells differentiate into distinct cell lineages. His laboratory studies the mechanisms involved in the induction and specification of mesoderm and definitive endoderm using ES cells and the embryoid bodies (EB) derived from them. His group recently identified a novel precursor that develops early within EBs and displays the unique capacity to generate cells of both the hematopoietic and endothelial lineages. This important discovery has led to identification of novel genes that may regulate differentiation of these lineages from hemangioblast progenitors. Dr. Keller became interested in stem cells during his Ph.D. research at the University of Alberta, where he studied hematopoietic colonies in chick embryonic development. He went on to do postdoctoral work with Robert Phillips at the Ontario Cancer Institute, where he studied hematopoietic stem cells and multilineage progenitors in mice. Dr. Keller was professor at National Jewish Hospital and the University of Colorado in Denver, before joining the faculty at the Mount Sinai School of Medicine. He is currently the director of the Black Family Stem Cell Institute and Professor of Gene and Cell Medicine.

2006 Symposium Topic: Lineage specific differentiation of ES cells

Arnold Kriegstein

Arnold Kriegstein has a long and distinguished career in both neurobiology and stem cell research, highlighted by his discovery that radial glial cells are the predominant form of neural stem cell in the mammalian central nervous system (CNS). Of particular note has been his ability to bridge across disparate disciplines. These have ranged from his pioneering work in determining how to breed the sea slug Aplysia to study its nervous system during his PhD in Dr. Kandel's laboratory, to conducting the first whole cell patch clamp recordings in brain slices, and to applying his findings from studies in neurogenesis of model organisms to the analysis of human neurological disorders. His present interests are centered on understanding the basic cell biology underlying neurogenesis in the developing mammalian CNS. Dr. Kriegstein is presently the Director of the Institute for Stem Cell and Tissue Biology at UCSF School of Medicine.

2006 Symposium Topic: Neural stem and progenitor cells in cortical development

Erika Matunis

Erika Matunis is particularly interested in the molecular mechanisms that regulate stem cell renewal. She began her research career studying heterogeneous nuclear ribonucleoproteins (hnRNPs) and showed that hnRNPs play an essential role in Drosophila oogenesis. These studies led her to characterize genes that restrict proliferation of stem cells during Drosophila spermatogenesis. This initial focus on stem cell proliferation gave way to broader questions of control of stem cell self-renewal and of regeneration of germ line stem cells. Recently she showed that differentiating cells in the Drosophila testis can in fact reverse their path and de-differentiate to become germ line stem cells. Her work intersects with fundamental aspects of stem cell maintenance, tissue regeneration, fertility and numerous other processes of medical importance. Her talk will focus on the molecular events that convert differentiating cells into stem cells in the Drosophila testis. Dr. Matunis is an Assistant Professor in the Department of Cell Biology at Johns Hopkins University, School of Medicine in Baltimore.

2006 Symposium Topic: Converting differentiating cells into stem cells in the Drosophila testis

Ben Scheres

Ben Scheres is interested in pattern formation, the nature of plant stem cells, and cell cycle control in the model plant Arabidopsis thaliana. Much of the recent work in his lab has focused on the genes and the genetic networks that maintain and establish the root stem cell niche, which gives rise to the post-embryonic root mass. Early work in the lab revealed the niche organization of the root stem cells, establishing the positional importance of a small set of Quiescent Center cells in maintaining the niche. Recent work in the lab has identified critical genes that control stem cell fate and feedback mechanisms between these genetic pathways and hormone gradients. The elucidation of these stem cell pathways has helped uncover the early genetic events in tissue regeneration in other work from the Scheres lab. In the control of meristem size in the root, the lab established a role for a RETINOBLASTOMA RELATED protein in Arabidopsis. Together this work has been critical in shaping the understanding of plant stem cells and the mechanistic and genetic parallels between stem cells in plants and animals. Dr. Scheres is presently Professor in the Department of Biology at the University of Utrecht in the Netherlands.

2006 Symposium Topic: Stem cells: tales from another kingdom

Azim Surani

Azim Surani discovered the phenomenon of genomic imprinting in mammals. These studies demonstrated that the chromosomes of egg and sperm are different; as a consequence, the expression of certain genes depends on whether they are inherited from the mother or father. He demonstrated that these differences rely on epigenetic modifications of DNA that occur during the formation of egg and sperm and persist throughout embryonic development. His recent work has focussed on the specification and properties of the mouse germ cell lineage. These studies identified a number of genes that mark the germ line lineage in the early embryo, including Blimp1, a key determinant of germ cell specification. Surani's landmark findings on epigenetic reprogramming and specification of the germ line provide the foundation for many issues related to stem cell biology. Dr. Surani is the Marshall-Walton Professor at the Wellcome Trust/Cancer Research UK Gurdon Institute of Cancer and Developmental Biology. He is also a Professorial Fellow of King's College, Cambridge. Among many honors, Dr. Surani is a fellow of the Royal Society, he was awarded a doctorate honoris causa by Uppsala University and was awarded the Royal Society Gabor Medal.

2006 Symposium Topic: Germ line, stem cells and epigenetic programming