Inhibition of two-step urinary bladder carcinogenesis by the somatostatin analogue RC-160.
Fisher 344 female rats were exposed for 4 weeks to the initiator carcinogen N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) 0.05% in the drinking water and thereafter to the promoter carcinogen mitomycin C (0.08 mg per animal per week) intravesically for 12 weeks. High incidence of urinary bladder transitional cell cancers was observed (17 in situ and 17 invasive carcinomas among 40 rats). When the somatostatin analogue RC-160 (D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2) was administered s.c. at the dose of 50 micrograms per animal per day during 6-week period of promotion with mitomycin C, the incidence of urinary bladder cancer was dramatically reduced. Only 1 in situ carcinoma was observed among 20 rats and only preblastomatous lesions (dysplasias and papillomas) occurred. This effect could indicate that RC-160 interferes with the process of promotion by induction of enhanced apoptosis (programmed cell death) of the dysplastic urothelial cells. RC-160 could be tried therapeutically for the hormonal prevention of malignant transformation of preneoplastic lesions in the urinary bladder.
Szende
B
B
First Institute of Pathology and Experimental Cancer Research, Semmelweis University Medical School, Budapest, Hungary.
Juhasz
E
E
Lapis
K
K
Schally
A V
AV
D000595:Amino Acid Sequence; D000818:Animals; D002295:Carcinoma, Transitional Cell / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D016923:Cell Death / Q000187:drug effects; D003043:Cocarcinogenesis; D005260:Female; D008969:Molecular Sequence Data; D011230:Precancerous Conditions / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control; D051381:Rats; D011916:Rats, Inbred F344; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*
C051458:vapreotide; D013004:Somatostatin