title: Prevention of breast cancer growth, invasion, and metastasis by antiestrogen tamoxifen alone or in combination with urokinase inhibitor B-428.
abstract: Urokinase (urokinase plasminogen activator, uPA) and its cell surface receptor (uPA receptor, uPAR) play an important role in a variety of physiological and pathological processes requiring cell migration and tissue remodeling. Using our syngeneic model of uPAR overexpression by the rat breast cancer cell line Mat B-III, we have examined the ability of the nonsteroidal antiestrogen, tamoxifen (TAM), and of a selective synthetic inhibitor of uPA, 4-iodo benzo[b]thiophene-2-carboxamidine (B-428), to inhibit expression of uPA and uPAR as well as cell growth, invasion, and metastasis of wild-type Mat B-III cells and of cells overexpressing uPAR (Mat B-III-uPAR). Both TAM and B-428 inhibited uPAR gene transcription, mRNA expression, protein production and also decreased the proliferative and invasive capacity of Mat B-III and Mat B-III-uPAR. The effects of TAM and B-428 were more pronounced when these agents were tested in combination. Both control and experimental cells (1 x 10(6) cells) were inoculated orthotopically into the mammary fat pad of syngeneic female Fisher rats, and animals were infused i.p. with either TAM and B-428 alone or in combination for 2 weeks. Control animals receiving vehicle alone developed large tumors and macroscopic metastases to lungs, liver, and lymph nodes. In contrast to this, experimental animals receiving TAM and B-428 showed a significant decrease in primary tumor volume and metastases. Combination therapy had especially marked effects in blocking progression of the primary tumor in experimental animals inoculated with highly aggressive Mat B-III-uPAR cells. These results underscore the utility of anti-proteolytic agents (B-428) in addition to standard hormone therapy (TAM) in advanced breast cancer patients where the uPA/uPAR system plays a key role in tumor progression.
authors.affiliation: Department of Medicine, McGill University and Royal Victoria Hospital, Montreal, Canada.
authors.forename: R H
authors.initials: RH
authors.lastname: Xing
authors.forename: A
authors.initials: A
authors.lastname: Mazar
authors.forename: J
authors.initials: J
authors.lastname: Henkin
authors.forename: S A
authors.initials: SA
authors.lastname: Rabbani
mesh_terms: D000578:Amidines / Q000494:pharmacology*; D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D004965:Estrogen Antagonists / Q000494:pharmacology*; D005260:Female; D009361:Neoplasm Invasiveness / Q000517:prevention & control; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D055293:Receptors, Urokinase Plasminogen Activator; D013629:Tamoxifen / Q000494:pharmacology*; D013876:Thiophenes / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects*; D014568:Urokinase-Type Plasminogen Activator / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: C097398:4-iodine-benzo(b)thiophene-2-carboxamidine; D000578:Amidines; D018931:Antineoplastic Agents, Hormonal; D004965:Estrogen Antagonists; C524900:Plaur protein, rat; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D013876:Thiophenes; D013629:Tamoxifen; D014568:Urokinase-Type Plasminogen Activator