The CAMPRIMOX mouse model: a powerful tool for identifying novel genes involved in prostate cancer m

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The CAMPRIMOX mouse model a powerful tool for
identifying novel genes involved in prostate
cancer metastasisEdward W. Howard, MD PhD, XH
Wang, PhD, YC Wong, PhD Resident,
Department of Internal Medicine, Georgetown
University Hospital, Washington DC, USA
Department of Anatomy, University of Hong Kong,
Hong Kong SAR
Abstract Prostate cancer is the second commonest
cause of male cancer death in the United States,
causing the loss of 29,400 Americans in the past
year alone. Despite these statistics, in a large
proportion of cases foci of cancer may exist
within the prostate for many years without ever
becoming clinically significant. The difference
between these cases and those that result in
death or debilitation from bony and visceral
involvement is the ability of the prostate cancer
cells to invade and metastasize. Due to
difficulties in studying the process of
metastasis in laboratory settings, the mechanisms
of prostate cancer metastasis, as with other
carcinomas, is poorly understood. One reason for
this is the lack of suitable models for studying
this process. We herein present a new tool for
such studies the CAMPRIMOX mouse model, which
enables detailed analysis of the metastatic
cascade and potentially the identification of
novel targets for therapeutic intervention.
CAMPRIMOX stands for Comparative Analysis of
Monoclonal PRImary and Metastatic Orthotopic
Xenografts. In this model, monoclonal prostate
cancer cells are implanted into the prostate of
immunosuppressed SCID mice, which then forms a
metastatic tumor. By culturing cells from the
primary tumor and any secondary deposits and
performing comparative genomics or proteomics,
the genes involved in metastatic progression may
be elucidated. We demonstrate that prostate
cancer cells derived from secondary deposits,
here using circulating tumor cells as an example,
are more invasive, demonstrate decreased
expression of epithelial cell markers and are
resistant to anoikis and stress-induced
apoptosis. Using proteomic analysis, we further
demonstrate that endoplasmic reticulum chaperone
molecule GRP94 is downregulated in circulating
tumor cells and that this correlates with
clinical specimens of human prostate cancer. The
success of this initial study suggests that using
DNA microarray technology and proteomics, the
identification of novel therapeutic targets is
possible using the CAMPRIMOX mouse and we propose
future studies using this model.
F. Comparative Analysis of Primaru and Metastatic
Recultured Cell LinesReveals Novel Gene Involved
GRP94

• Introduction
• Mechanisms of metastasis in prostate cancer are
  poorly understood
• Circulating tumor cell stage of metastasis
  incompletely characterized
• Insufficient models for investigational studies
• In vitro models not representative of clinical
  situation
• Potential for significant improvements
• Here we introduce the CAMPRIMOX mouse, a novel,
  unique and proven efficaceous model for studying
  metastatic progression.
• CAMPRIMOX is
• Comparative Analysis of Monoclonal PRImary and
  Metastatic Orthotopic Xenograft cells

C. Orthotopic Implantation of Monoclonal
prostate cancer cellsand metastatic growth
G. GRP94 is downregulated in tumors in comparison
with BPH samples, and correlates with Gleason
score, indicating the efficacy of this model
I. Monoclonal prostate cancer cells
III. Visualization of tumor growth and metastasis
using external bioluminescent imaging
II. Surgical Orthotopic Implantation
D. Isolation by primary culture of primary and
metastatic cell lines
Lymph Nodes
Metastatic cell lines isolated and expanded in
primary culture ready for future experimentation
Metastatic deposits

• Conclusions CAMPRIMOX Mouse
• Novel model for studying metastasis
• CAMPRIMOX is Comparative Analysis of Monoclonal
  PRImary and Metastatic Orthotopic Xenograft cells
• Utilizes the mouse to allow tumor cells to
  spontaneously develop metastatic capacity
• Directly compares cells with and without
  metastatic capacity
• Demonstrated and published capacity to identify
  genes involved in prostate cancer metastasis,
  here GRP94
• Several further cell lines have already been
  isolated for study and there is a possibility of
  future work looking at solid metastasis as well
  as circulating tumor cells ()
• Future work will likely involve DNA genotype
  microarray studies as well as proteomic analysis
• Possibility for further characterizing metastatic
  processes in any number of solid malignancies
  given the increasing popularity of orthotopic
  mouse models in translational research.

Lung

Pleura
Opportunity for future research
Mouse with metastatic cancer
Primary Culture of Primary
Primary tumor
GFPC3
Primary Culture of Circulating Tumor Cells
Blood sample from tail vein
GFCTC
Note that the metastatic cells are less adhesive
and more resistant to apoptosis than the primary
cells