Molecular Mechanisms of Early Pituitary
Patterning in Zebrafish and Human Embryos
Rolf Karlstrom, Ph.D., Biology, UMass Amherst
Theonia Boyd, M.D., Pathology, Baystate Medical Center
The goal of this project is to better understand the early embryonic
events that lead to the formation of a functional pituitary gland.
Defects in human pituitary development such as hypopituitarism
affect a large number of children and are responsible for a variety
of developmental problems including growth hormone deficiencies
(GHD) [1] . Holoprosencephaly (HPE) is the most common human developmental
defect affecting the forebrain and face, and has been linked to
defects in hedgehog (Hh) signaling [2] . Amazingly, it is estimated
that 1 in 250 conceptuses is affected by HPE. We are focusing our
studies on understanding how cell-cell communication via the Hh
morphogen shapes the hormone secreting lobe of the pituitary, the
adenohypophysis. We have recently shown that zebrafish Hh pathway
mutations result in defective pituitary development, specifically
in the early induction and patterning of the adenohypophysis [3,
4] . Different zebrafish Hh pathway mutations affect pituitary
patterning to different degrees, indicating that a range of pituitary
phenotypes can result from different Hh signaling defects [5] .
This range of defects may mirror the variety of defects seen in
humans displaying both HPE and hypopituitarism. Over the last two
years we have shown that hedgehog signaling is needed during three
distinct developmental stages for the 1) induction, 2) patterning,
and 3) maintenance of pituitary cell fates. In particular, we have
shown that prolactin (PRL) secreting cells develop in the anterior
portion ofthe adenohypophysis and require Hh signaling to differentiate
( [5] , see attached manuscript).
We propose to continue to use the zebrafish as a simple system
to help us understand how Hh signaling influences differentiation
of distinct endocrine cell populations. We are now focusing our
zebrafish research on the Hh responsive transcription factors of
the Gli family in order to better understand how pituitary cells
interpret Hh signals during the induction and patterning phase
of adenohypophysis formation. Using tissue obtained from the Baystate
Medical Center, we will apply the information learned in fish to
the analysis of early adenohypophysis development in human embryos.
Using our fish data as a guide, we will determine which cell types
are most likely to be affected by defects in Hh signaling. Finally,
we will explore whether defects in hedgehog signaling are correlated
with specific pituitary defects in humans. Characterizing the genetic
bases for hypopituitarism would be a crucial first step toward
the early detection and eventual treatment of these prevalent congenital
disorders.
Effective Date- June 1, 2003
Intervention in Function of Tumor Cell Surface Membrane
Receptors: A Potential Role of Environmental Toxicants
Kathleen Arcaro, Ph.D., Vet and Animal Science, UMass Amherst
Christopher Otis, M.D., Surgical Pathology, Baystate Medical Center
Bert Zuckerman, Ph.D., Professor Emeritus, UMass Amherst
Surface membrane receptors play a vital role in the growth and
proliferation of cancer cells, and in signaling and recognition
among these cells. An objective of the current proposal is to broaden
the understanding of the mechanisms underlying carcinogenesis by
experimentally perturbing the functions of the glycolipid and/or
glycoprotein membrane receptors in primary human breast cultures
and in a human breast-cancer cell line. To achieve this objective
we will establish primary breast culture techniques, both dispersed-cell
and explant culture, in our laboratory. A second objective of this
proposal is to investigate the role of estrogens in the glycolipid/glycoprotein
cell signaling and adhesion. These studies will form the basis
for future studies on the role of environmental estrogens and anti-estrogens
in tumor formation.
It is only through advances in knowledge of the basic mechanisms
underlying breast cancer that there will be progress towards a cure.
The current project is designed to define parameters of recognition
and signaling between breast cells and breast-cancer cells, and can
lead to intervention in signals between these cells.
Effective Date- June 1, 2003
Modification of Immune Responses by Notch Expressing Mammary
Epithelial Cells
Barbara Osborne, Ph.D., Vet & Animal Science, UMass Amherst
Sallie Smith Schneider, Ph.D., Immunology, Baystate/UMass Biomedical
Institute
Giovanna Crisi, M.D., Pathology, Baystate Medical Center
Evidence from one of our labs (SSS) has shown that mammary epithelial
cells transfected with the active intracellular domain of Notch
produce a soluble product that suppresses T cell responses. In
Particular, supernatants from these cells, as compared to cells
transfected vector control, contain an immunomodulatory factor(s)
that surpresses interferon-?(IFNy) secretion from activated T cells.
The other PI (BAO) is actively investigating signaling pathways in
T cells that regulate IFNy. Lastly, the thrid PI (GC) is a pathologist
at Baystate Medical Center with a special interest in breast cancer
and will be able to provide sections of human breast tumors and the
skill to help evaluate the immunohistochemical results. The background
of these three investigators bring all of the skills necessary to
address the aims of this application.
Objectives: 1. To determine whether a reduction in Notch expression
in mammanry epithelial cells restores IFNy production by lymph
node T cells. In this aim, we ask if either an antisense Notch1
constrcut or a small RNA (siRNA) directed against Notch1 can abrogate
the production of the immunomodulatory factor produced by Notch
transfected mammary epithelial cells. 2.To determine at what point
in the T cell activation pathway supernatants from mammary epithelial
block INFy production. In this aim, we will attempt to define how
the immunomodulatory factor suppresses IFNy production in activated
T cells. 3. To establish whether there is a inverse correlation
between Notch expression in human breast tumors and analyzed using
immunohistochemistry (IHC).
Effective Date- June 1, 2003
Computer-Aided 3-Dimensional Evaluation of the Volume
and Shape of Ductal Carcinoma in Situ (DCISI) in Excisional Biopsies
of the Breast and their Relationship of Risks of Residual Disease
Recurrence
Monroe Rabin, Ph.D., Physics, UMass Amherst
Robert Goulart, M.D., Pathology, Baystate Medical Center
Methods currently used for estimating the size of Ductal Carcinoma
in Situ (DCIS) in tissue removed during a lumpectomy of the breast
may underestimate the span of DCIS in 3-dimensions, may not clearly
describe the relationship of tumor size and proximity to the margin
of excised tissue, and may not yield reasonable predictions for
the probability of residual disease in the unexcised tissue. We
wish to address all these issues by producing an automated, computer-generated
model of the breast and excised tissue along with an accurate representation of
the locations of detected DCIS. This model will be 3-dimensional
and can be rotated in space on the cmputer screen to enable the
physician to get a better idea of the location and the extent of
DCIS relative to the excised tissue. Measurments of distances from
DCIS to any of the margins of the tissue will also be possible
and straightforward. We want to test the hypothesis that this will
improve the ability to calculate the probability of residual disease
in the breast. It should also aid the planning any future treatment
(surgery, radiation) that may be needed.
A side benefit of this method will be the retention of both printed
and pictorial records on computer files that can be accessed by
qualified medical personnel at any time. This technology is only
beginning to be implemented at hospitals around the country.
Effective date- June 1, 2003
Ubiquitous Wireless Infrastructure for
Smart Mobile Access and Support of Teletrauma and Disaster Management
Aura Ganz, Ph.D., Electrical and Computer Engineering, UMass Amherst
Richard Wait, Ph.D., M.D., Surgery, Baystate Medical Center
Imtiaz A. Munshi, M.D., Surgery, Baystate Medical Center
The objective of this work is to study the needs of the trauma
specialist in mobile tele-trauma situations and develop a wireless
architecture denoted as Smart Light Medical Proxy (SLiMP) that
will respond to those needs. SLiMP is configured within a mobile
unit (ambulance) enabling a ubiquitous delivery of expert trauma
care into areas where such care was either non-existent or delayed.
SLiMP manages and smartly converts the intense amount of digital
information embedded in the medical data into compressed data that
can fit in the small dynamic wireless pipeline. The study will
demonstrate the quantitative and qualitative aspects of how SLiMP
can successfully support teletrauma in situations not supported
with current technologies.
Effective date – January 1, 2003
Endoscopic Surveillance of Barrett’s Esophagus
in Genetically-Predisposed Mice
Joseph Jerry, Ph.D., Vet and Animal Science, UMass Amherst
Richard Arenas, M.D., Surgical Oncology, Baystate Medical Center
Barrett’s esophagus represents a gradual transformation of
the esophageal epithelium through metaplastic changes that can lead
to dysplasia and subsequent adenocarcinoma. This alteration of the
epithelial lining results from constant exposure to acid-bile reflux;
however, reflux alone cannot induce Barrett’s metaplasia.
Barrett’s metaplasia also requires a genetic susceptibility
that has yet to be determined. Recent studies, however, implicate
two tumor suppressor genes in Barrett’s esophagus, the Adenomatous
Polyposis Coli (APC) gene and the TP53 (p53) gene. We hypothesize
that APC-deficiency and p53-deficiency will lead to Barrett’s
metaplasia and subsequent cancer when esophageal epithelium is exposed
to chronic acid-bile reflux. The objective of this proposal is to
surgically induce esophageal reflux in two mouse models genetically
mutated for APC and p53, then prospectively follow the metaplasia-dysplasia-carcinoma
sequence through serial endoscopic evaluations. To determine whether
mice deficient in APC and p53 will develop Barrett’s metaplasia
and subsequent cancer when exposed to chronic esophageal reflux,
APC-deficient Min (Apc+/-) mice and p53-deficient (Trp53 +/- &
-/-) mice will undergo total gastrectomy with formation of an esophago-jejunostomy.
Endoscopy will be performed with a newly devised rodoscope based
on advances in high-resolution fiberoptics. This technologic advance
will allow us to document Barrett’s related changes in the
mouse esophagus without unnecessary euthanization and will offer
unique prospective information regarding the onset and progression
of the metaplasia-dysplasia-carcinoma sequence in genetically-predisposed
mouse models.
Effective date – January 1, 2003
Identification of Breast Cancer Susceptibility
Genes: The Road to BRCAX
Joseph Jerry, Ph.D., Vet and Animal Science, UMass Amherst
Sandra L. Petersen, Ph.D., Biology, UMass Amherst
Qing Jackie Cao, M.D., Pathology, Baystate Medical Center
Christopher N. Otis, M.D., Pathology, Baystate Medical Center
Kristin Stueber, M.D., Surgery, Baystate Medical Center
At least 1/3 of all breast cancer is attributed to heritable factors,
but known breast cancer susceptibility genes account for only ~10%
of breast cancers. We have used mice that differ in their
incidence of mammary tumors to genetically map additional genes
that may influence breast cancer in women. This effort has
identified a 10 Mb region on mouse chromosome 7 that bears gene(s)
that cause a >2-fold increase in relative risk of developing
mammary in mice that are homozygous for the susceptibility allele
compared to the heterozygotes. We have identified candidate
genes within the interval that are differentially expressed between
the strains. The candidate genes are being examined to identify
their pattern of expression during mammary gland development and
whether expression may be lost in a subset of human breast cancers.
Through collaborations we are also examining the presence of polymorphisms
in humans that may be associated with increased risk of breast cancer.
Effective date – January 1, 2003
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