Angiogenesis with pericyte abnormalities in a transgenic model of prostate carcinoma.
BACKGROUND
Previous studies of the TRansgenic Adenocarcinoma of the Mouse Prostate (TRAMP) model vasculature suggest that, as tumors develop, vessels invade the glandular epithelium. However, changes in the vasculature are difficult to study in conventional thin tissue sections. The authors used a new approach to characterize morphologic and architectural changes of blood vessels and pericytes during tumor development in TRAMP mice.


METHODS
Eighty-micron cryostat sections of normal prostate and three histopathologic stages of TRAMP tumor sections, classified by epithelial cell E-cadherin immunoreactivity, were immunostained with vascular endothelial cell and pericyte receptor antibodies and evaluated by confocal microscopy.


RESULTS
In the normal mouse prostate, capillaries were most abundant in the fibromuscular tunica between the epithelium and smooth muscle of the ductules. In the prostatic intraepithelial neoplasia (PIN) stage, vessels accompanied epithelial cell protrusions into the ductule lumen but remained in the connective tissue at the basal side of the epithelium. Well differentiated tissues had extensive angiogenesis with five times the normal mean vascularity outside ductules. Vessels were of variable diameter, were associated with an increased number of pericytes, and some had endothelial sprouts. Angiogenic blood vessels from poorly differentiated adenocarcinomas were tortuous, variable in caliber, and lacked the normal hierarchy. Pericytes on these vessels had an abnormal phenotype manifested by alpha-smooth muscle actin expression and loose association with endothelial cells. Angiogenesis and loss of vascular hierarchy were also found in human prostate carcinoma.


CONCLUSIONS
Vascular abnormalities, which begin at the PIN stage and intensify in well differentiated and poorly differentiated tumors, may be useful readouts for early detection and treatment assessment in prostate carcinoma.
Ozawa
Michael G
MG
Department of Anatomy, University of California at San Francisco, San Francisco, California 94143-0130, USA.
Yao
Virginia J
VJ
Chanthery
Yvan H
YH
Troncoso
Patricia
P
Uemura
Akiyoshi
A
Varner
Amanda S
AS
Kasman
Ian M
IM
Pasqualini
Renata
R
Arap
Wadih
W
McDonald
Donald M
DM
D000230:Adenocarcinoma / Q000098:blood supply* / Q000378:metabolism; D000818:Animals; D015820:Cadherins / Q000378:metabolism; D004195:Disease Models, Animal; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D009389:Neovascularization, Pathologic; D020286:Pericytes / Q000378:metabolism / Q000473:pathology*; D019048:Prostatic Intraepithelial Neoplasia / Q000098:blood supply* / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000098:blood supply* / Q000378:metabolism; D051381:Rats
D015820:Cadherins