Arrest of Hormone-dependent Mammary Cancer Growth in Vivo and in Vitro by Cholera Toxin

摘要: Growth of 7,12-dimethylbenz(α)anthracene-induced mammary carcinoma in rat was arrested by daily s.c. injections cholera toxin. At a dose 2 µg/200-g rat, tumors regressed to 50% their initial size within weeks, and 85% completely 4 5 weeks. The same response toxin observed with another hormone-dependent tumor, MTW9, but not the hormone-independent tumors, DMBA No. 1 MT 13762. latter result consistent lack these hormone removal (ovariectomy) or N 6, O 2′-dibutyryl cyclic adenosine 3′:5′-monophosphate treatment. growth-inhibitory effect dependent, upon cessation treatment resumed growth; after complete regression, however, did reappear until 6 months termination An amount as high 10 µg/day/200-g injected over 6-week period showed no systemic toxicity animals. growth human breast cancer cells (MCF-7) culture also inhibited supplement concentration 100 ng/ml, cell replication ceased days. inhibitions, both vivo vitro , were accompanied marked increases cellular content type II 3′:5′-monophosphate-dependent protein kinase activity well decrease estrogen binding activity. Thus, extinction can be achieved toxin, an agent that stimulates intracellular system.