Applications of Mouse Models To Cancer Research
Jeff Green, M.D.
Chief, Transgenic Oncogenesis and Genomics Section Laboratory of Cancer Biology and Genetics NCI, Bethesda, MD
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Growth Hormone Transgenic Mice
Genetically Engineered Mice: Limited only by our imagination!
Topics: • advantages/disadvantages of mouse models • designing and generating models • validating models as surrogates for human studies • applying models for preclinical
Why Mice? • • • • • • • • • •
They don’t sue! No IRB (but ACUC!) Human trials are expensive Human trials take a long time Genetic background Can identify modifier genes Can control conditions precisely Can validate a target Can generate complex genetic models Can study stage-specific effects of intervention • Can easily perform combination studies
Advantages of GEM Over In
vitro Approaches
• Study gene in context of entire animal • In the context of an intact immune system • Effects on animal development • Study cancer stage progression • Study tissue-tissue interactions • Study genetic interactions • Identify modifier loci • Tools for pre-clinical testing
Disadvantages: • A mouse is only a mouse! • Targeting to correct compartment • Hormone-responsiveness of promoters • Developmental timing • Expression levels of transgene • Pharmacology • Tissue composition • Poor models of metastases
• • • •
Environment
chemical exposures radiation/UV exposure viral infections immune suppression
Aging
Genetic Background • race • genetic modifiers • familial cancer syndromes
Cancer Risk
Life style • • • •
diet/alcohol exercise obesity mentstrual history/parity history
Prior cancer history
Somatic Gene Dysregulation/Muta Oncogene tion
• activation/over-expression • Loss of suppressor gene function • Chromosomal/gene rearrangement
Intelligent Design
Creating mice in our own molecular image
Oncogenic Targets of GEM Mammary CA Models Growth Factors/Receptors
Steroid Hormone Signaling Aromatase
IGF
TGF β
Her2/neu PyMT
Estrogen
Androgen Retinoids Vitamin D
ER AR
IGFR
TGFβR
PIP-2
PI3K
PIP-3
PKC
RXR VDR
PTEN
MEK AKT
JAK
RAS
SMADs STAT
ERK
Prostoglandins
BRCA1 myc
Transcriptional Regulation p53
TAG
CELL CYCLE
Rb
COX-2
Inflammatory Response
Oncogenesis In GEM
Genetic Aberration(s) (~All cells)
- p53 - BRCA1
?
Cancer
ONCOGENES: Her2/neu Myc Ras PyMT SV40 Tag
P53; Rb
?
Mouse
Cancers
Human Cancers
Biology Histopathology
Therapeutic Trials
Genomic Analyses
Therapeutic Trials
Expression Profiling
Bioinformatics
Model Validation
Transgenic Targeting to the Mammary and Prostate Glands • tissue-specificity • cell-compartment specificity • developmental timing • hormone-independent promoter Hormone
Promoter
Oncogene
BAC Recombineering
STRATEGIES FOR HOMOLOGOUS RECOMBINATION
NEO
II
II
TK
III
III
Insertion/Selection NEO II
III
NEO
II
TK
III
II
III
Deletion/Selection NEO
KNOCK-IN STRATEGY
NEO
* II
II
TK
III
III
Replacement NEO
* II
III
CONDITONAL KNOCK-0UT (Cre-lox)
NEO
L
L
II
TK
III
II
III
Replacement/Selection NEO
L
L II
III
L
NEO
L II
III
X Promoter cre recombinase
II
NEO
L III
Examples of Useful Cancer Models Brain Ovary Prostate Breast Lung Colon Pancreas
Ras + Akt Glioma Model (E. Holland)
Ovarian Cancer Model (S. Orsulic)
C3(1)/Tag Transgenic Model
Mammary Lesion Prostate Tumor Progression Progression
N
PIN
CA Human
C3(1)/Tag
Mouse
ATG
I *
SV40
Tag
Tumor Progression in Breast Cance QuickTime™ and a Photo - JPEG decompressor are needed to see this picture.
Human
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Apoptosis
10% 0%
C3(1)/Tag Mouse
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↑ Bax
Shibata, EMBO, 2001
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Normal
DCIS/MIN
Invasive CA
Pancreatic Cancer (D. Tuveson)
Prostate
Courtesy of N. Greenberg
Lung
(T. Jacks)
Colon
Additional GEM Technologies • Viral delivery systems (retrovirus/lentevirus) • RACS system • Embryonic reconstitution • Chimeric mice (VEGF; ets K.O.s)
Embryonic Reconstitution Embryonic U.G. Sinus
Retrovirus + ras/myc
The RCAS-TVA Technology
LTR
gag
pol
SA
SD
SA
RCAS - a viral vector derived from ALV-A TVA - avian receptor for ALV-A
env
LTR X X
TVA
gag, pol env gene X
Y.Li
ene Delivery with RCAS Vector Pr
LTR
gag
tv-a transgeni c mouse
TV-a
pol
env
LTR
active oncogenes DN TSGs inducible genes Cre recombinase Tet activator marker genes
Conditional Expression Models: • Control of tissue specificity and developmental timing of gene expression. • Study oncogene dependence.
TissueSpecific Promoter
TK or CD
TISSUE SPECIFIC ABLATION TISSUE SPECIFIC ABLATION WITH DRUG WITH DRUG
TissueSpecific Promoter
Tetoperator Promoter
Tettransactivator protein (on/off)
Gene of Interest
TEMPORAL CONTROL OF GENE EXPRESSION TEMPORAL CONTROL OF GENE EXPRESSION WITH TETRACYCLINE WITH TETRACYCLINE
Oncogene Dependence of Tumors
In vivo Imaging
GFP
LUC
Advanced In Vivo Imaging Techniques
Choosing the right model What is your question?
evelopment of Pathology Nomenclature fo Mouse Models of Mammary Cancer
• need to standardize nomenclature • need to translate between human and mouse pathology • need to assess similarities/differences between human and mouse (Cardiff et al., Oncogene, 2000.)
Comparing Genomic Aberations Between Mouse Models and Human Cancers (Chin L and Depinho R)
How Can the Mouse Help Us Better Understand Breast Cancer?
elp sift through molecular chao
Integrating the Mouse with Human Genomic Studies • identify oncogenic signatures. • improve identification of biologic networks through identification of functionally conserved genes.
Enormous Genetic Diversity
Defined Genetic Background
Global Expression Profiiling of Tumors
Evolutionarily Conserved Genetic Networks
High Throughput Microarray
Sorlie et al., PNAS (2001
ER- stem cell ER-
C3(1)/Tag P53-/BRCA1-/-;p53+/-
Progenitor cell ER-
MMTV-her2/neu MMTV-ras MMTV-myc MMTV-PyMT
ER+
P53-/-
Common Genes/Biomarkers Related to Similar Biologic State
ER+ Mouse
ER+ Human
The Mouse-Human Classifier is the Best Predictor of ER Status
Human classifier
Mouse/Human classifie Mouse classifier
Training
Test
Mouse/Human Classifier ER+ ER-
Using the model for pre-clinical testing
Inhibition of Mammary Tumor Progression By Recombinant Endostatin
Control
Endostatin
Lizt, 2001
Flk-1/DKR X
Angiogenes is
VEGF Receptor Inhibitors
GSK: J. Stafford and Rakesh Kumar
• GW2286 as prototype receptor kinase inhibitor • Specific inhibitor of KDR phosphorylation/Flk-1 (VEGFR-2). H3C
Enzyme IC50 (nM)
N N H
OMe
NH
mVEGFR2 48
src 758
EGFR 7,079
OMe
N N
hVEGFR2 8
N H
OMe
•
Inhibits VEGF-induced endothelial cell proliferation and KDR phosphorylation.
•
Inhibits tumor vascular density, and Matrigel plug and
micropocket assays. • cornea no toxicity
CDK2 1,622
Survival Survival (percentage)
Inhibition of tumor growth with VEGFRII inhibitor Control 10 mg 100 mg
100 75 50 25 0 16
18
20
22
24
26
Age (wk)
Huh, J. et al. 2005, Oncogene
INITIATION
PROGRESSION Dormant
Mammary Intraepithelial Neoplasia
Invasive CA
Metastasis
At what stages do preventive agents inhibit cancer?
C3(1)/Tag Mammary Histopatholog P53 Rb
Human C3(1)/Tag Mouse
A
B
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D
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Normal
C
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E
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F
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8-12 weeks 17+ weeks Invasive CA DCIS/MIN
“Chemoprevention” DHEA DFMO 9-cRA Endostatin
The Metastatic Process
dormancy
metastasis
1. Genetic 2. Epigenetic-intracellular -extracellular:ECM
Chambers AF (2002):Nat Rev Cancer 8:563-
MCF-7 cells are dormant in vivo
MDA-MB-231
2 weeks post injection
MCF-7
9 weeks post injection
SCOM
H&E
Experimental Alterations of Risk Factors Generation of GEM Models With Genetic Changes Relevant to Human Cancer
Evaluation of Model Phenotype: • Disease natural history • Histopathology • Hormone responsiveness (breast and prostate) • Cell of origin • Genome integrity • Gene expression • Protein markers
• Energy balance • Nutritional composition • Hormone exposure • Carcinogens • Pregnancy (breast) • Infectious agents • UV exposure (skin) •Radiation •Genetic Background
Selection of Candidate Models
Determining Predictive Value of GEM Models
Assessment of Response in Models
ADMINISTRATION OF PREVENTIVE AGENT(S)
• • • • • • • •
Clinical Trials In Humans
Tumor latency Tumor multiplicity Growth rate Metastases Survival Histologic changes Gene expression Biomarkers
Functional conservation of genes/networks
Green and Hudson, Nature Reviews Cancer, 2005
Lab Members (current/former) Dalit Barkan Christina Bennett Alfonso Calvo Isabel Chu Kartiki Desai Tamaro Hudson Jung-im Huh Mark Hoenerhoff Claudine Kavanaugh Kristin Kee Hark Kim Zi-yao Liu Aleksandra Michalowska Ting Qiu Masa-aki Shibata Christy Tomlinson Min Zhu