Green tea polyphenol suppresses tumor invasion and angiogenesis in N-butyl-(-4-hydroxybutyl) nitrosamine-induced bladder cancer.
BACKGROUND
Green tea polyphenol (GTP) suppresses malignancy in bladder cancer cell lines. However, the detail of its anti-carcinogenic effect in vivo is not fully understood. This study investigated the effect of GTP on bladder tumor size and angiogenesis in mice given N-butyl-(-4-hydroxybutyl) nitrosamine (BBN), with and without GTP.


METHODS
Eight-week-old female C3H/He mice were treated with and without 0.05% BBN solution for 14 or 24 weeks. In addition, they were also treated with and without 0.5% GTP solution for the same periods. Histopathological diagnosis was established using hematoxylin and eosin staining, and microvessel density (MVD) was estimated by counting CD34- and von Willebrand factor-positive vessels in the tumor area.


RESULTS
At 14 weeks, cancer cells were detected in BBN and BBN+GTP mice [5/14 (35.7%) and 3/14 (21.4%), respectively, p=0.678]. At 24 weeks, the incidence of cancer cells was also similar between the groups (BBN+GTP: 61.9% vs. BBN: 82.6%; p=0.179). However, the frequency of invasive tumors in BBN+GTP mice was significantly lower (23.8%; p=0.030) than in those given BBN alone (65.2%). Tumor volume and MVD of intratumoral and stromal region in the BBN+GTP group were also significantly lower than in BBN mice.


CONCLUSIONS
The results showed that GTP had no anti-carcinogenic effect, but inhibited tumor growth and invasion in mice with established bladder cancer, at least in part through the regulation of angiogenesis. Our data suggest that GTP seems to suppress tumor development in bladder cancer.
Sagara
Yuji
Y
Department of Urology, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, Japan.
Miyata
Yasuyoshi
Y
Nomata
Koichiro
K
Hayashi
Tomayoshi
T
Kanetake
Hiroshi
H
D020533:Angiogenesis Inhibitors / Q000627:therapeutic use*; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use*; D002085:Butylhydroxybutylnitrosamine; D028241:Camellia sinensis; D005260:Female; D005419:Flavonoids / Q000627:therapeutic use*; D051379:Mice; D009361:Neoplasm Invasiveness; D010636:Phenols / Q000627:therapeutic use*; D010936:Plant Extracts / Q000627:therapeutic use*; D059808:Polyphenols; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology
D020533:Angiogenesis Inhibitors; D000972:Antineoplastic Agents, Phytogenic; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D002085:Butylhydroxybutylnitrosamine