RANK ligand mediates progestin-induced mammary epithelial proliferation and carcinogenesis

• Published in: Nature (London) Vol. 468; no. 7320; pp. 103 - 107
• Main Authors: Branstetter, Dan, Pinkas, Jan, Dougall, William C, Erwert, Ryan, Miller, Robert, Jacob, Allison P, Jones, Jon, Gonzalez-Suarez, Eva, Roudier-Meyer, Martine P
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04.11.2010; Nature Publishing Group
• Subjects: 631/45/127/1220; 631/67/1347; 692/420/755; 9,10-Dimethyl-1,2-benzanthracene - administration & dosage; 9,10-Dimethyl-1,2-benzanthracene - adverse effects; Animal tumors. Experimental tumors; Animals; Apoptosis; Biological and medical sciences; Breast cancer; Breast Neoplasms - metabolism; Breast Neoplasms - pathology; Carcinogenesis; Carcinogens; Care and treatment; Cell Proliferation - drug effects; Cell Transformation, Neoplastic - chemically induced; Cell Transformation, Neoplastic - drug effects; Cell Transformation, Neoplastic - pathology; Disease Models, Animal; Epithelial Cells - drug effects; Epithelial Cells - metabolism; Epithelial Cells - pathology; Experimental genital and mammary tumors; Female; Genetic aspects; Health aspects; Hormone replacement therapy; Humanities and Social Sciences; Humans; Immunohistochemistry; letter; Lung Neoplasms - secondary; Mammary Neoplasms, Experimental - chemically induced; Mammary Neoplasms, Experimental - genetics; Mammary Neoplasms, Experimental - metabolism; Mammary Neoplasms, Experimental - pathology; Mammary Tumor Virus, Mouse - genetics; Mammary Tumor Virus, Mouse - physiology; Medical sciences; Medroxyprogesterone Acetate - administration & dosage; Medroxyprogesterone Acetate - adverse effects; Mice; Mice, Inbred C57BL; Mice, Transgenic; multidisciplinary; Neoplasm Invasiveness; Physiological aspects; Precancerous Conditions - pathology; Precancerous Conditions - prevention & control; Progesterone; Progesterone - administration & dosage; Progesterone - adverse effects; Progestins - administration & dosage; Progestins - adverse effects; Proteins; RANK Ligand - antagonists & inhibitors; RANK Ligand - genetics; RANK Ligand - metabolism; Receptor Activator of Nuclear Factor-kappa B - genetics; Receptor Activator of Nuclear Factor-kappa B - metabolism; Risk factors; Rodents; Science; Science (multidisciplinary); Tumor proteins; Tumors; United States; Cell proliferation; Breast disease; Receptor activator Nfkb ligand; Cytokine; Rodentia; Transgenic animal; Breast cancer; Malignant tumor; Carcinogenesis; Ovarian hormone; Progestagen; Mammary gland diseases; Vertebrata; Mammalia; Cancerology; Mouse; Tumor necrosis factor; Epithelial cell; Progesterone; Sex steroid hormone; Cancer
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature09495

RANK ligand (RANKL), a TNF-related molecule, is essential for osteoclast formation, function and survival through interaction with its receptor RANK. Mammary glands of RANK- and RANKL-deficient mice develop normally during sexual maturation, but fail to form lobuloalveolar structures during pregnancy because of defective proliferation and increased apoptosis of mammary epithelium. It has been shown that RANKL is responsible for the major proliferative response of mouse mammary epithelium to progesterone during mammary lactational morphogenesis, and in mouse models, manipulated to induce activation of the RANK/RANKL pathway in the absence of strict hormonal control, inappropriate mammary proliferation is observed. However, there is no evidence so far of a functional contribution of RANKL to tumorigenesis. Here we show that RANK and RANKL are expressed within normal, pre-malignant and neoplastic mammary epithelium, and using complementary gain-of-function (mouse mammary tumour virus (MMTV)-RANK transgenic mice) and loss-of function (pharmacological inhibition of RANKL) approaches, define a direct contribution of this pathway in mammary tumorigenesis. Accelerated pre-neoplasias and increased mammary tumour formation were observed in MMTV-RANK transgenic mice after multiparity or treatment with carcinogen and hormone (progesterone). Reciprocally, selective pharmacological inhibition of RANKL attenuated mammary tumour development not only in hormone- and carcinogen-treated MMTV-RANK and wild-type mice, but also in the MMTV-neu transgenic spontaneous tumour model. The reduction in tumorigenesis upon RANKL inhibition was preceded by a reduction in pre-neoplasias as well as rapid and sustained reductions in hormone- and carcinogen-induced mammary epithelial proliferation and cyclin D1 levels. Collectively, our results indicate that RANKL inhibition is acting directly on hormone-induced mammary epithelium at early stages in tumorigenesis, and the permissive contribution of progesterone to increased mammary cancer incidence is due to RANKL-dependent proliferative changes in the mammary epithelium. The current study highlights a potential role for RANKL inhibition in the management of proliferative breast disease.