CL1-GFP: an androgen independent metastatic tumor model for prostate cancer.
OBJECTIVE
The mechanisms responsible for tumor progression to androgen independence in prostate cancer (CaP) remain unknown. To characterize these changes and provide a basis for rational therapeutic strategies for advanced CaP, an in vivo model from a highly aggressive androgen independent CaP cell line with distinct cellular and molecular properties was developed.


METHODS
An aggressive androgen-independent cell line designated CL1 was derived from a slow-growing, and androgen-dependent, parental LNCaP cell line through in-vitro androgen-deprivation and selection. CL1 was stably transfected with a green fluorescence protein gene (CL1-GFP) and orthotopically injected into SCID mice. The pathologic behavior, histology, and molecular determinants of CL1 tumor and metastases were determined and characterized by standard light and fluorescent microscopy, and quantitative RT-PCR analysis.


RESULTS
CL1 is an anaplastic prostate cancer cell line which demonstrates extensive local invasion and metastases to various organs that can be visualized via GFP expression. When compared with parental LNCaP cells, RT-PCR analysis of the tumor revealed an over-expression of EGFR, b-FGF, VEGF, TGF-beta, IL-8, IL-6, and bcl-2 and a down regulated expression of the p53, E-cadherin and PTEN. In contrast to LNCaP cells, CL1 tumors express lower levels of androgen receptor and barely detectable PSA mRNA.


CONCLUSIONS
CL1-GFP represents an aggressive androgen-independent CaP tumor model derived through androgen deprivation whose pathologic development and molecular properties in animals resembles the clinical characteristics of hormone refractory prostate cancer (HRPC). Metastatic sites of CL1-GFP can be visualized with fluorescence microscopy offering a unique therapeutic model for the evaluation of drug sensitivity and other therapeutic modalities.
Patel
B J
BJ
Department of Urology, University of California at Los Angeles, Los Angeles, California 90095-1738, USA.
Pantuck
A J
AJ
Zisman
A
A
Tsui
K H
KH
Paik
S H
SH
Caliliw
R
R
Sheriff
S
S
Wu
L
L
deKernion
J B
JB
Tso
C L
CL
Belldegrun
A S
AS
D000728:Androgens / Q000502:physiology; D000818:Animals; D015820:Cadherins / Q000378:metabolism; D004195:Disease Models, Animal; D016228:Endothelial Growth Factors / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D008222:Lymphokines / Q000378:metabolism; D008297:Male; D051379:Mice; D016513:Mice, SCID; D008856:Microscopy, Fluorescence; D011471:Prostatic Neoplasms / Q000503:physiopathology / Q000556:secondary*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D000728:Androgens; D015820:Cadherins; D016228:Endothelial Growth Factors; D015850:Interleukin-6; D016209:Interleukin-8; D008222:Lymphokines; D019253:Proto-Oncogene Proteins c-bcl-2; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D016222:Fibroblast Growth Factor 2; D066246:ErbB Receptors