In:
Molecular Cancer Therapeutics, American Association for Cancer Research (AACR), Vol. 5, No. 4 ( 2006-04-01), p. 1073-1078
Abstract:
The ability of the farnesyl transferase inhibitor R115777 to act as a cancer therapeutic/preventive agent and to modulate proliferation/apoptosis markers was determined in the methylnitrosourea-induced model of mammary carcinogenesis. Female Sprague-Dawley rats were given methylnitrosourea at 50 days of age. In the prevention study, R115777 (5, 16, or 50 mg/kg body weight/d), beginning 5 days after methylnitrosourea treatment, decreased the formation of mammary cancers by 6%, 42%, and 75%, respectively. Approximately 50% of the mammary cancers that developed had HaRas mutations. Only 1 of 15 tumors that grew out in the presence of R115777 (16 or 50 mg/kg body weight/d) had a HaRas mutation. In the therapeutic study, a surgical biopsy of a mammary cancer was done to determine HaRas status, and growth of the cancer was then followed during treatment of the rat with R115777. Virtually every cancer with a HaRas mutation underwent complete regression within 3 weeks, whereas tumors without a HaRas mutation had variable responses to the inhibitor. Both of these studies implied a high sensitivity of tumors with HaRas mutations to the effects of R115777. In order to understand the preferential susceptibility of tumors with HaRas mutations, rats with a palpable cancer were treated with R115777 for a period of 36 or 96 hours prior to sacrifice, and the proliferation and apoptosis levels in the cancers were determined. The proliferative index was significantly ( & gt;85%) decreased in all mammary cancers with HaRas mutations, whereas variable responses were observed in cancers without HaRas mutations. Apoptosis was also measured and a 5-fold increase was observed in HaRas mutant tumors, again with varying responses in the HaRas wild-type cancers. Thus, R115777 was active in the prevention and therapy of these chemically induced mammary cancers, but was strikingly more effective in cancers with HaRas mutations. [Mol Cancer Ther 2006;5(4):1073–8]
Type of Medium:
Online Resource
ISSN:
1535-7163
,
1538-8514
DOI:
10.1158/1535-7163.MCT-05-0398
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2006
detail.hit.zdb_id:
2062135-8
detail.hit.zdb_id:
2063563-1
SSG:
12
