Cheryl S. Watson, Ph.D.

Publications (Pubmed)

Editor-in-Chief, Endocrine Disruptors (Landes)

For 2nd Life Members - please visit me in my virtual office at UTMB Island Alpha (85,115,39)

Professor, Dept.of Biochemistry & Molecular, Biology,Member: Comprehensive Cancer Center, Center of Interdisciplinary Research on Women's Health, Sealy Center for Env. Health & Medicine, Internal Advisory Board-Center for Addiction Research

cswatson@utmb.edu
Route: 0645
512 Basic Science Building

 

Cheryl S. Watson, Ph.D.

Professor

Education:

  • BS and MS, Purdue University, 1972 and 1974
  • PhD in Cell Biology, Baylor College of Medicine, 1980
  • Postdoc at Nat’l Inst. Medical Research, London (Estrogen Action)
  • Postdoc at Population Council at Rockefeller Univ (Androgen Action)
  • ELAM (Executive Leadership in Academic Medicine) Fellow, 2004-5

Membership in Graduate Programs:

  • Biochemistry &Molecular Biology
  • Neurosciences
  • Cell Biology / Cancer Cell Biology
  • Toxicology

Research Program

Rapid nongenomic actions of steroids are relevant to many different types of cellular functions, including actions on hormone-responsive cancer cells. These nongenomic mechanisms are novel compared to the classical nuclear transcription actions of steroids, and we are now trying to chart their relevance in human diseases where they may reveal new targets for therapies. We investigate the actions of both physiological estrogens and estrogen mimetics (xenoestrogens such as environmental estrogens, phytoestrogens, and pharmaceutical estrogens) on rapid nongenomic signaling cascades.

Membrane forms of estrogen receptors (mERα, mERβ, and GPR30) mediate nongenomic responses (as opposed to the nuclear versions of ERs that mediate their action by directly binding to DNA). In our most frequently used model -rat pituitary tumor cells -- mERα mediates the rapid secretion of prolactin, in part via increasing the entrance of calcium through L-type calcium channels. These mERs also mediate the activation of a series of kinases (which can be cell type- and function-specific), culminating in integration at the activity levels of several MAP kinases (ERKs, JNKs, p38). We have identified cell surface ERs by a variety of immunocytochemical and impeded ligand-binding methods (fluorescence, confocal, and digital image deconvolution microscopy) and signaling manipulations [using inhibitory antibodies (Abs), function-inducing Abs, and antisense/siRNA knockdowns of functional responses]. A sub-population of GH3 pituitary tumor cells were selected for enriched mERα expression using immunopanning and limiting dilution subcloning. These subclones show enhanced signaling and functional responses mediated by these receptors. The figure below illustrates our newest method of visualizing mERs on cells, the proximity ligation assay. This technique produces a signal when the distance between two epitopes are <35 nm apart. Abs to these epitopes are probed with two different anti-species secondary Abs that carry covalently attached complementary oligonucleotides. When the two epitopes are sufficiently close the Ab-attached oligonucleotides hybridize, producing a template for rolling circle DNA amplification, which can then be probed efficiently with fluorescent oligonucleotide probes. The signals appear as discreet dots. If two epitopes within the same protein are probed, then one sees the distribution of that protein alone, on or in cells. If Abs recognizing epitopes within two different proteins are used, the signal generated indicates a protein-protein interaction or close proximity. Below is an example of this type of imaging showing mERα alone on GH3/B6/F10 pituitary cells, and then ERα interacting with Gαi and caveolin I proteins.

Watson Image

ERα, Gαi, and caveolin are complexed at the cell surface. Proximity of two different epitopes(<35nm) allow amplification of a signal (red; cy3). Each sample was also counterstained for nuclei (blue; DAPI). Images show a Z-stack 3D rendering of confocal optical slices. Left panel: two different ERα epitopes were probed including one at the amino terminus (Ab ERα 21-32) and one at the carboxy terminus (Ab C542) before permeabilizing cells. Center panel: before permeabilizing the cells, the ERα Ab (C452) and its secondary Ab-linked Duolink probe was applied; after permeabilizing the cells the Gai Ab (C-10) and its secondary Ab-linked Duolink probe was applied. Right panel: ERα Ab (C542) and its probe were applied pre-permeabilization, and caveolin-1 Ab (N-20) and its probe were applied after cell permeabilization. A negative control omitting the primary Ab had little to no signal (not shown). Each red dot demonstrates the proximity of two epitopes in a non-nuclear pattern.

Breast cancer cells (MCF-7) and prostate cancer cells also have mERs. In these cells the level of mERs correlates with the ability of estrogens to activate several signaling cascades which initiate from the membrane to affect tumor cell numbers. Neuronal type cancer cells (PC-12) also have all three forms of mERs (α, β, and GPR30), which regulate neurotransmitter transporters in their membranes. We have also collaborated in the demonstration that mast cells and lymphocytes respond to both physiological and environmental estrogens via nongenomic signaling mechanisms (with the lab of Drs. Terumi Midoro-Horiuti and Randall Goldblum). We also worked with Dr. Bahiru Gametchu on studies visualizing the membrane glucocorticoid receptor which is involved in glucocorticoid-induced therapeutic apoptosis of leukemia and lymphoma cells.

We have further utilized the ability of these Abs to recognize both membrane and intracellular antigens to develop a 96-well plate assay to quantify receptors and the activation of a variety of other signaling proteins involved in these mechanisms. We use these assays to study the effects of xenoestrogens which mimic physiological estrogens as very potent signaling ligands through the nongenomic response pathway. Most xenoestrogens can activate kinases and a variety of second messengers at femtomolar-nanomolar concentrations in several types of endocrine cancer cells. There are hundreds of xenoestrogens contaminating the environment and our food supplies. Dr. Watson participates in a consortium of chemists and biologists trying to solve this difficult environmental problem: http://www.tipedinfo.com/

Dr. Watson has also pioneered the use of virtual world (Second Life) technologies and avatars for presenting public outreach explanations about this research field. Please see one of her talks via this YouTube link:

Dr. Watson is Editor-in-Chief of the journal Endocrine Disruptors: http://www.landesbioscience.com/journals/endo_dis/

2nd worldDr. Watson in 2nd Life (virtual world) visiting the walk-in cell at the 2nd Nature Island