Broadening of transgenic adenocarcinoma of the mouse prostate (TRAMP) model to represent late stage androgen depletion independent cancer.
BACKGROUND
The transgenic adenocarcinoma of the mouse prostate (TRAMP) model closely mimics PC-progression as it occurs in humans. However, the timing of disease incidence and progression (especially late stage) makes it logistically difficult to conduct experiments synchronously and economically. The development and characterization of androgen depletion independent (ADI) TRAMP sublines are reported.


METHODS
Sublines were derived from androgen-sensitive TRAMP-C1 and TRAMP-C2 cell lines by androgen deprivation in vitro and in vivo. Epithelial origin (cytokeratin) and expression of late stage biomarkers (E-cadherin and KAI-1) were evaluated using immunohistochemistry. Androgen receptor (AR) status was assessed through quantitative real time PCR, Western blotting, and immunohistochemistry. Coexpression of AR and E-cadherin was also evaluated. Clonogenicity and invasive potential were measured by soft agar and matrigel invasion assays. Proliferation/survival of sublines in response to androgen was assessed by WST-1 assay. In vivo growth of subcutaneous tumors was assessed in castrated and sham-castrated C57BL/6 mice.


RESULTS
The sublines were epithelial and displayed ADI in vitro and in vivo. Compared to the parental lines, these showed (1) significantly faster growth rates in vitro and in vivo independent of androgen depletion, (2) greater tumorigenic, and invasive potential in vitro. All showed substantial downregulation in expression levels of tumor suppressor, E-cadherin, and metastatis suppressor, KAI-1. Interestingly, the percentage of cells expressing AR with downregulated E-cadherin was higher in ADI cells, suggesting a possible interaction between the two pathways.


CONCLUSIONS
The TRAMP model now encompasses ADI sublines potentially representing different phenotypes with increased tumorigenicity and invasiveness.
Jeet
Varinder
V
Oncology Research Centre, Prince of Wales Hospital, Barker St., Randwick, NSW, Australia.
Ow
Kim
K
Doherty
Eboney
E
Curley
Ben
B
Russell
Pamela J
PJ
Khatri
Aparajita
A
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology*; D000728:Androgens / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004195:Disease Models, Animal; D018450:Disease Progression; D051861:Kangai-1 Protein / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009361:Neoplasm Invasiveness / Q000235:genetics; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D011944:Receptors, Androgen / Q000378:metabolism
D000728:Androgens; D014408:Biomarkers, Tumor; D015820:Cadherins; C497689:Cd82 antigen, mouse; D051861:Kangai-1 Protein; D011944:Receptors, Androgen