Download UNC GI Cancer SPORE - UNC

UNC GI Cancer SPORE
UNC GI Cancer SPORE's unique goals emphasize multidisciplinary translational research that
spans and links the population, clinical, and basic sciences. To decrease the burden of
colorectal cancer on the patient population at large we will: (1) determine the clinical importance
of new and existing targets on the colorectal cancer population (2) define the relationship of
these molecular abnormalities to racial disparities (3) evaluate how best to manipulate these
molecular targets for therapy, and (4)verify the target manipulation and effect in a group of
colorectal cancer patients. To decrease colorectal cancer mortality a better understanding of the
relationship of laboratory discoveries in signaling, oncogenesis and other molecular changes to
the clinical setting is needed. We have developed projects that will allow us to accomplish these
goals through the strong multi-disciplinary collaboration that already exists between clinical,
laboratory and population-based scientists in the UNC Lineberger Comprehensive Cancer
Center. The UNC GI Cancer SPORE consists of five projects, four core resources, a career
development program, and a developmental research program.
Project 1: Prognostic and Predictive Factors in Outcomes of Patients with Colorectal
Cancer: A Population-Based Study
Robert Sandler, M.D., M.P.H., Principal Investigator
Temitope Keku, Ph.D., Co-Principal Investigator
There is now evidence that molecular characteristics of colorectal cancer can influence
prognosis and predict response to therapy. The proposed study is motivated by the belief that
better information on prognostic and predictive factors will make it possible to tailor therapy to
maximize benefits and reduce cost, and by a desire to understand racial disparities in colorectal
cancer mortality. The specific aims of the study are: (1) To determine which patient, treatment
and molecular characteristics of colon tumors are independent predictors of prognosis. (2) To
determine interactions between tumor characteristics and treatment factors and the response to
therapy. (3) To determine whether racial differences in tumor characteristics are responsible for
the worse 5-year survival in colorectal cancer in blacks. The proposed study will take advantage
of data collected in a prospective, population-based study that will obtain exceptionally detailed
information on patient characteristics, treatment, outcomes as well as tumor blocks on 1000
newly-diagnosed colorectal cancer patients (600 whites and 400 blacks) drawn at random from
a diverse, mixed-race, 22 county area in North Carolina. The specific molecular characteristics
will include expression of protein products of genes involved in cell cycle, cell growth, apoptosis,
and cellular adhesion such as p53, k-ras, calcium binding protein S100A4, cyclin D, IGFII, TGFβRII, MLH1, and MSH2. These markers will be evaluated using multitumor tissue array blocks.
In addition, the study will use DNA from microdissected blocks to evaluate loss of heterogeneity
(LOH) on chromosomes 2p, 5q, 17p and 18q, and will assess microsatellite instability (MSI)
using BAT25, BAT26 and D17S250, D5S346, D2S123.
Project 2: Molecular Changes in the NFkB Pathway in Response to Chemoradiation
Therapy in Rectal Cancer
Al Baldwin, Ph.D., Principal Investigator
Carolyn Sartor, M.D., Co-Principal Investigator
Although early diagnosis for colorectal cancer has been significantly improved, the occurrence
of locally advanced colorectal cancer is still a major medical problem since these patients have
extremely poor prognosis. Clearly, new approaches for treatment of colorectal cancer are
needed. Two major obstacles which exist relative to standard radiation and chemotherapy
protocols are: (i) resistance of colorectal tumors to treatment and (ii) dose limitations of
treatment due to fibrosis of normal intestinal tissue. Radio- and chemoresistance are
characterized either as pre-existing resistance, based on constitutive expression of certain
proteins such as MDR1 or anti-apoptotic proteins such as Bcl-2 and on loss of pro-apoptotic
factors such as p53, or as inducible resistance. Inducible resistance is a relatively poorly
characterized phenomenon in which tumors transiently induce resistance following exposure to
treatment. In several studies, tumor response correlates with induction of apoptosis. Thus, it is
likely that one major component of tumor chemo/radioresistance is suppression of apoptosis.
We have reported that the transcription factor NF-κB provides a powerful anti-apoptotic
mechanism through its ability to transcriptionally regulate genes encoding proteins which
suppress apoptosis. Importantly, NF-κB activation is basally detected in colorectal tumor tissue
(although expression may predominantly be localized in tumor-associated macrophages) and is
strongly activated in tumor cells following radiation or chemotherapy exposure. Based on these
findings, we have shown that inhibition of NF-κB through a gene delivery approach strongly
potentiates chemotherapy-induced experimental colorectal tumor cytotoxicity through the
induction of apoptosis. Furthermore, we have used an FDA-approved drug (PS-341, a
proteasome inhibitor) which strongly blocks NF-κB activation to enhance colorectal tumor
xenograft responses to both radiation and to CPT-11 based chemotherapy.
We hypothesize that radiation-induced NF-κB activation and associated downstream
transcriptional responses will occur in colorectal tumors and that this will correlate with a
decreased therapeutic response by providing an anti-apoptotic signal. To test our hypothesis,
we propose to: (i) determine whether radiation-induced activation of NF-κB and associated
induced genes occurs in pre-operative radiochemotherapy and determine whether this
responses correlates with clinical response and (ii) determine the ability of PS-341 to modulate
NF-κB-dependent responses and to measure the toxicity of PS-341 delivered with pre-operative
radiochemotherapy.
Additionally, these studies will measure NF-κB activation and induction of transcription factordependent transcription responses in normal intestinal tissue following radiochemotherapy as a
potential molecular correlate for cancer therapy-induced intestinal fibrosis. We also hypothesize
that adjuvant radiochemotherapy responses will be improved and overall toxicity reduced
through the use of more specific inhibitors of the NF-κB pathway. Thus, we will measure the
efficacy of NF-κB inhibitors as an adjuvant approach with radiation or with the newest
combination of chemotherapy regimens on different experimental tumors including liver
metastases. These phase I clinical studies and basic translational experiments have the
potential to significantly improve therapeutic approaches for advanced colorectal cancer.
Project 3: Investigation of ERBB signaling in Colorectal Cancers during Liver Metastasis
David Threadgill, Ph.D., Principal Investigator
Benjamin Calvo, M.D., Co-Principal Investigator
Colorectal cancer afflicts 135,000 Americans per year and 38% of these patients will die of
disseminated disease most commonly to liver lung and bone. Of the patients that die of this
disease, 70% have liver metastases and a significant 10% have liver-only disease. Even in
those patients with metastases to multiple organ sites, the extent of liver disease remains the
primary determinant of survival.
Over the last two decades we have empirically learned that patients with liver only metastases
have improved survival when treated aggressively. Untreated, patients with hepatic only
metastases have a median survival of only 12-21 months and the five year survival of patients
with unresected metastasis is close to 0%. In sharp contrast, resection of metastases in patients
with liver only disease yields five year survival rates of 20-40% and 10 year survival rates of
20%. Furthermore, the most common site of disease recurrence after resection is the liver.
Consequently, liver metastases are a primary determinant of survival in patients with stage IV
colorectal cancer.
Building upon preliminary data linking ERBB receptor activity to colorectal cancer progression
and metastasis, we hypothesize that small molecule ERBB inhibitors, if optimally employed, will
retard the growth and dissemination of metastatic colorectal cancer. We also hypothesize that
colorectal cancer can also arise independently of ERBB and that an understanding of these
mechanisms will allow us to design better therapies. Thus, using a combination of clinical
smaples and pre-clinical mouse models, we propose to investigate the mechanism of how
metastatic colon cancer uses EGFR and other ERBB receptor signaling to establish residency
in the liver and to identify markers for response to dual EGFR/ERBB2 inhibitors during treatment
of metastatic lesions. Experiments are planned to identify transcriptional profiles unique to
EGFR independent colorectal cancer development.
Project 4: Targeting the RAS>ERK Pathway for Colorectal Cancer Treatment
Channing Der, Ph.D. Principal Investigator
H.J. Kim, M.D., Co-Principal Investigator
Mutations in Ras are associated with 50% of colorectal carcinomas, indicating the importance of
aberrant Ras activation in tumor development and progression. Recently, mutations in B-Raf,
the downstream target of Ras, have been identified in 10% of colorectal carcinomas. The
presence of B-Raf mutations in tumors distinct from those with Ras mutations indicates that
these mutations are genetically equivalent, such that either one confers a similar advantage.
These data support the critical contribution of the Raf>MEK>ERK mitogen-activated protein
kinase cascade in Ras-mediated oncogenesis. Currently, pharmacologic inhibitors of two
kinases in this cascade, Raf and MEK, have been developed and are under evaluation in
clinical trials. Such target-based drugs are believed to represent the key future direction for anticancer drug discovery. However, one major complication that has slowed the clinical
development of target-based anti-cancer drugs (e.g., epidermal growth factor receptor
inhibitors) is continued uncertainty regarding whether aberrant activation of the target alone is
sufficient to define the patient population that will be responsive to these drugs. This uncertainty
is based, in part, on the fact that the presence of an altered target may simply have a
correlative, rather than a causal, role in oncogenesis. Based on observations in preclinical
models, this will also be a concern for efforts to evaluate the clinical efficacy of anti-Ras
therapies. It is likely that Ras mutation status alone will not be sufficient to define the subset of
colorectal cancers that will be responsive to inhibitors of Ras signaling, specifically to inhibitors
of the Raf and MEK protein kinases. Instead, we hypothesize that other approaches, such as
microarray gene profiling, will be needed to determine the subsets of Ras mutation positive
colorectal cancers that will be responsive to anti-Raf or anti-MEK therapy. Therefore, the broad
goal of this project will be to determine whether a group of patients with colorectal carcinomas
that harbor mutated Ras show gene expression profiles that may have clinical relevance in
predicting sensitivity to anti-Ras and anti-Raf/MEK therapeutic strategies.
Project 5: Determination of the Role of Fucosyltransferases in Colorectal Cancer
Initiation and Progression
Brent Weston, M.D. Principal Investigator
Robert Sandler, M.D., M.P.H., Co-Principal Investigator
Selectin-mediated cell adhesion has been implicated in the metastasis of colorectal carcinoma
(CRC), and the carbohydrate ligand components sialyl Lewis x (sLex) and sialyl Lewis a (sLea)
on tumor cells have long been considered markers for development and progression of human
carcinoma. Recent data showing important roles for inflammation in CRC pathogenesis point to
selectin ligands as potential translational targets. Although corresponding glycosyltransferase
expression is complex in malignant cells and tumor specimens, sLex and sLea synthesis
appears to be largely controlled by the human α(1,3)fucosyltransferase gene families. Two of
these genes are highly expressed in CRC: FUT3 and FUT6. Our group has shown that inhibition
of sLex/sLea expression in CRC cells by antisense FUT3 sequences results in markedly
reduced CRC metastases in nu/nu mice. Furthermore, antisense inhibition of FUT6-- which is
often co-expressed with FUT3 in CRC and is inducible with inflammatory cytokines-- results in
decreased carcinoma proliferation invitro and in vivo. Mutations in FUT3 and FUT6 have been
described in diverse human populations, but no information has been available to determine the
effect(s), if any, of these null phenotypes on development and/or progression of CRC. Similarly,
expression at the transcript level has been limited by lack of adequate human data sets and
samples. Over the past several years at UNC, SPORE investigators have helped assemble
large CRC patient data sets with appropriate specimens. We propose to: 1. Identify FUT3
and/or FUT6 mutations associated with polyp and/or CRC development and examine potential
interactions with use of non-steroidal anti-inflammatory drugs (NSAIDs) and other clinical
variables; 2. Examine FUT transcript levels in polyps and CRC lesions at various stages of
progression; and 3. Combine FUT antisense oligodeoxynucleotides with NSAIDs for
experimental therapy of CRC in vitro and in nu/nu mice models. Our long term goal is extend
the pre-clinical use of these agents to appropriate patient populations as our understanding of
selectin ligand function grows.
Core 1: Administration
Joel Tepper, M.D., SPORE Director
Richard Goldberg, M.D., SPORE Co-Director
Robert Sandler, M.D., M.P.H., SPORE Co-Director
David Threadgill, Ph.D., SPORE Co-Director
Under Dr. Joel Tepper, SPORE Director, the Administrative Core supports the UNC GI Cancer
SPORE's overall scientific/translational goals by providing leadership and day-to-day
operations/administration. The SPORE Director leads the core. An Administrative Director, a
Program Coordinator, and an Administrative Assistant comprise the staff. The Core organizes:
the intra and inter-SPORE interactions, administrative/scientific oversight of all research
projects, cores, and developmental programs; and the activities of the external, internal, and
advocate advisory committees. This Core also monitors SPORE expenditures and addresses
grant management issues.
Core 2: Genomics
David Threadgill, Ph.D., Core Director
Chuck Perou, Ph.D., Core Co-Director
The Genomics Core will provide experimental planing, scientific services and computational
support for SPORE projects using DNA microarrays. The facility is contained within the UNC
Genomics Core & Microarray Facility housed in the Lineberger Comprehensive Cancer Center
and adjacent to the core director's lab. It maintains centralized equipment for microarray
production, utilization, and analysis. The Core also produces customized microarrays and
maintains libraries of long-oligos and cDNA for printing the custom microarrays. To maximize
efficiency and generate consistent quality results, the Genomics Core will provide complete
microarray research services to SPORE projects. Investigators will isolate RNA and submit
samples. The facility will perform quality control on all samples and prepare fluorescent probes
for hybridization with either in-house produced or commercial micorarrays. The Genomics Core
will provides computer hardware and analysis programs to collect and pre-process raw data
before being transmitted to the Bioinformatics Core for databasing and analysis. The Genomics
Core will initially support three of the SPORE projects. Its use will most likely expand to other
projects and development studies as needed.
Core 3: Biostatistics and Bioinformatics
Joseph Ibrahim, Ph.D, Core Director
Fred Wright, Ph.D., Core Co-Director
The UNC GI Cancer SPORE Biostatistics and Bioinformatics Core was developed from the
newest core resources at the UNC Lineberger Comprehensive Cancer Center. Substantial
expansion in faculty recruitment, with an emphasis on genetic analysis, and an investment in
hardware and associated databases has prepared the Center to launch an integrated yet
expanded core resource to support the GI SPORE projects. Senior faculty recruits Joe Ibrahim
and Fred Wright will provide new intellectual leadership for this core. Both have substantial
experience in biostatistics, new areas of statistical genetics, integration with clinical research,
and Cancer Center programs for translational research. In addition to expanded leadership,
involvement from the Departments of Statistics and Biostatistics have expanded the Cancer
Center's and thus the UNC GI Cancer SPORE's capabilities in this area.
A substantial investment in databases to store gene expression microarray data from multiple
platforms and to import data from other institutions is already leading to productive translational
research at the Cancer Center. Continued development of parallel clinical and epidemiologic
databases for clinical trials and population-based data will be linked to our microarray databases
via an honest broker model that will be overseen by the GI SPORE and the UNC Lineberger
Biostatistic cores.
The five projects in the GI SPORE present interesting challenges, both as translational research
and as biostatistical/bioinformatics problems. Complementary skills possessed by the Core
faculty will lead to new approaches to gene expression data as well as cross-platform analysis.
Input from the Core Directors and other members of this core is described within both the
project write-ups and in this section.
Top-notch senior and promising junior faculty, an emphasis on translational and genetic
research at the Cancer Center, and continuing investment in data management will provide an
excellent resource for the UNC GI Cancer SPORE's projects with large data sets. The Core will
provide appropriate input into design, management, and analysis as the most promising lines of
translational research are pursued.
Core 4: Tissue Procurement and Analysis
William Funkhouser, M.D, Core Director
John Woosley, M.D., Core Co-Director
The Tissue Procurement and Analysis Core will build on existing services within the UNC
Lineberger Comprehensive Cancer Center and within the UNC Department of Pathology and
Lab Medicine. This core will provide centralized tissue procurement, tissue processing, tissue
storage, and tissue distribution of normal and malignant colorectal tissues from UNC Hospitals
as well as maintenance and enhancement of the existing GI tissue bank. This Core will support
the listed GI SPORE projects, working with both clinical and research investigators to meet their
unique research needs.
The Tissue Procurement component is responsible for collection and freezing of surplus fresh
tissues from the UNC Division of Surgical Pathology. All Tissue Procurement frozen specimens
will be reviewed by a board-certified Anatomic Pathologist to ensure that representative frozen
tissue is banked and distributed. Potential downstream frozen tissue handling includes routine
frozen section stains, frozen immunophenotyping, frozen section laser capture microdissection,
and mRNA extraction.
The Tissue Analysis component is responsible for collection and analysis of diagnostic paraffin
blocks and slides following Surgical Pathology case diagnosis finalization. Potential downstream
fixed tissue handling includes paraffin tissue microarray manufacture, routine paraffin section
stains, paraffin immunophenotyping, paraffin section laser capture microdissection,
immunophenotypic analysis, and immunophenotype digital image collation.
In conjunction with the Biostatistics and Bioinformatics Core (Core #3), customized HIPAAcompliant databases will be used to track release, disposition, and return of both frozen and
fixed specimens, including frozen tissue, paraffin blocks, tissue section slides, and patient
reports, providing a coordinated system of quality control, specimen tracking, and efficient
specimen distribution of specimens to appropriate investigators.
This Core will implement policies and procedures as necessary to support the above services,
to address relevant technical, medical, and legal issues, and to comply with relevant ethical
standards as defined by UNC School of Medicine Institutional Review Board (IRB) and Federal
HIPAA policies.
Developmental Research Program
The UNC GI Cancer SPORE's Developmental Research Program will promote novel
translational gastrointestinal cancer research in clinical/translational science, population
sciences, gene/molecular discovery, and other relevant areas. The program will fund two types
of investigators: those with GI cancer research experience whose projects are central to the
SPORE's translational mission; and, investigators (or teams) with limited GI cancer experience
whom we wish to attract to the field. The Developmental Research Program includes
mechanisms for stimulating grant applications, evaluating and selecting projects, and monitoring
progress. The mechanisms include consultation with and/or evaluation by the GI Cancer
SPORE;'s senior leadership (Executive Committee), the External Advisory Board, and GI cancer
Advocates Advisory Board. This program will use mechanisms that have been successful for
other developmental research endeavors at the UNC Lineberger Comprehensive Cancer Center
and UNC Chapel Hill, including the UNC SPORE in Breast Cancer.
Information cited from www.cancer.gov.