title: Agonists and antagonists of GnRH-I and -II reduce metastasis formation by triple-negative human breast cancer cells in vivo.
abstract: Metastasis to bone is a frequent problem of advanced breast cancer. Particularly breast cancers, which do not express estrogen and progesterone receptors and which have no overexpression/amplification of the HER2-neu gene, so called triple-negative breast cancers, are considered as very aggressive and possess a bad prognosis. About 60% of all human breast cancers and about 74% of triple-negative breast cancers express receptors for gonadotropin-releasing hormone (GnRH), which might be used as a therapeutic target. Recently, we could show that bone-directed invasion of human breast cancer cells in vitro is time- and dose-dependently reduced by GnRH analogs. In the present study, we have analyzed whether GnRH analogs are able to reduce metastases of triple-negative breast cancers in vivo. In addition, we have evaluated the effects of GnRH analogs on tumor growth. To quantify formation of metastasis by triple-negative MDA-MB-435 and MDA-MB-231 human breast cancers, we used a real-time PCR method based on detection of human-specific alu sequences measuring accurately the amount of human tumor DNA in athymic mouse organs. To analyze tumor growth, the volumes of breast cancer xenotransplants into nude mice were measured. We could demonstrate that GnRH analogs significantly reduced metastasis formation by triple-negative breast cancer in vivo. In addition, we could show that GnRH analogs significantly inhibited the growth of breast cancer into nude mice. Side effects were not detectable. In conclusion, GnRH analogs seem to be suitable drugs for an efficacious therapy for triple-negative, GnRH receptor-positive human breast cancers to prevent metastasis formation.
authors.affiliation: Department of Gynecology and Obstetrics, Georg-August-University, Robert-Koch-Street 40, 37075 Göttingen, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Schubert
authors.forename: Thomas
authors.initials: T
authors.lastname: Hawighorst
authors.forename: Günter
authors.initials: G
authors.lastname: Emons
authors.forename: Carsten
authors.initials: C
authors.lastname: Gründker
mesh_terms: D020087:Alu Elements / Q000235:genetics; D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D001859:Bone Neoplasms / Q000188:drug therapy / Q000556:secondary; D001943:Breast Neoplasms / Q000145:classification / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000627:therapeutic use*; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000556:secondary; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis / Q000188:drug therapy / Q000235:genetics; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011966:Receptors, LHRH / Q000819:agonists* / Q000037:antagonists & inhibitors*; D011980:Receptors, Progesterone / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D018931:Antineoplastic Agents, Hormonal; D007987:Gonadotropin-Releasing Hormone; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011966:Receptors, LHRH; D011980:Receptors, Progesterone