8792

TNFRSF11A

tumor necrosis factor receptor superfamily, member 11a, NFKB activator;TNFRSF11A;tumor necrosis factor receptor superfamily, member 11a, NFKB activator

Paget disease of bone 2|loss of heterozygosity, 18, chromosomal region 1|osteoclast differentiation factor receptor|receptor activator of NF-KB|receptor activator of nuclear factor-kappa B|tumor necrosis factor receptor superfamily member 11A

18q22.1

protein-coding

Inflammatory mechanisms influence tumorigenesis and metastatic progression even in cancers whose aetiology does not involve pre-existing inflammation or infection, such as breast and prostate cancers. For instance, prostate cancer metastasis is associated with the infiltration of lymphocytes into advanced tumours and the upregulation of two tumour-necrosis-factor family members: receptor activator of nuclear factor-kappaB (RANK) ligand (RANKL) and lymphotoxin. But the source of RANKL and its role in metastasis have not been established. RANKL and its receptor RANK control the proliferation of mammary lobuloalveolar cells during pregnancy through inhibitor of nuclear factor-kappaB (IkappaB) kinase-alpha (IKK-alpha), a protein kinase that is needed for the self-renewal of mammary cancer progenitors and for prostate cancer metastasis. We therefore examined whether RANKL, RANK and IKK-alpha are also involved in mammary/breast cancer metastasis. Indeed, RANK signalling in mammary carcinoma cells that overexpress the proto-oncogene Erbb2 (also known as Neu), which is frequently amplified in metastatic human breast cancers, was important for pulmonary metastasis. metastatic spread of Erbb2-transformed carcinoma cells also required CD4(+)CD25(+) T cells, whose major pro-metastatic function was RANKL production. Most RANKL-producing T cells expressed forkhead box P3 (FOXP3), a transcription factor produced by regulatory T cells, and were located next to smooth muscle actin (SMA)(+) stromal cells in mouse and human breast cancers. The dependence of pulmonary metastasis on T cells was replaceable by exogenous RANKL, which also stimulated pulmonary metastasis of RANK(+) human breast cancer cells. These results are consistent with the adverse impact of tumour-infiltrating CD4(+) or FOXP3(+) T cells on human breast cancer prognosis and suggest that the targeting of RANKL-RANK can be used in conjunction with the therapeutic elimination of primary breast tumours to prevent recurrent metastatic disease.

BACKGROUND: Receptor activator of NFkB (RANK), its ligand (RANKL) and the decoy receptor of RANKL (osteoprotegerin, OPG) play a pivotal role in bone remodeling by regulating osteoclasts formation and activity. RANKL stimulates migration of RANK-expressing tumor cells in vitro, conversely inhibited by OPG. MATERIALS AND METHODS: We examined mRNA expression levels of RANKL/RANK/OPG in a publicly available microarray dataset of 295 primary breast cancer patients. We next analyzed RANK expression by immunohistochemistry in an independent series of 93 primary breast cancer specimens and investigated a possible association with clinicopathological parameters, bone recurrence and survival. RESULTS: Microarray analysis showed that lower RANK and high OPG mRNA levels correlate with longer overall survival (P = 0.0078 and 0.0335, respectively) and disease-free survival (P = 0.059 and 0.0402, respectively). Immunohistochemical analysis of RANK showed a positive correlation with the development of bone metastases (P = 0.023) and a shorter skeletal disease-free survival (SDFS, P = 0.037). Specifically, univariate analysis of survival showed that "RANK-negative" and "RANK-positive" patients had a SDFS of 105.7 months (95% CI: 73.9-124.4) and 58.9 months (95% CI: 34.7-68.5), respectively. RANK protein expression was also associated with accelerated bone metastasis formation in a multivariate analysis (P = 0.029). CONCLUSIONS: This is the first demonstration of the role of RANK expression in primary tumors as a predictive marker of bone metastasis occurrence and SDFS in a large population of breast cancer patients.

BACKGROUND: Breast cancer, the most common cancer affecting women in the USA and UK, is known to have a high frequency of osteolytic bone metastasis. Receptor activator of nuclear-kappaB (RANK), RANK ligand (RANKL) and osteoprotegerin (OPG) are a group of important regulators for osteoclast differentiation and activation. These molecules have been implicated in bone metastasis. Since the discovery of the triad of RANK, RANKL and OPG in healthy bone turnover, a better understanding of these factors in bone metastasis has been sought. MATERIALS AND METHODS: Using our clinical breast cancer cohort, the transcript levels of RANK, RANKL and OPG were examined using real-time quantitative-polymerase chain reaction (qPCR). expression of these molecules in the immortalised breast cancer cell lines MCF-7 and MDA-MB-231 was also analyzed using qPCR following treatment with beta-oestradiol in a concentration-dependent manner. RESULTS: RANK, RANKL and OPG were all shown to be expressed in the breast cancer cell lines examined. Transcript levels were shown to be reduced in tumour samples when compared with normal tissue. Reduced RANK expression was associated with a worse clinical outcome and levels were significantly reduced in patients with general metastasis, bone metastasis and those who had died of the disease. Patients with reduced RANKL expression were more likely to develop local recurrence, bone metastasis or die from the disease. Using Kaplan-Meier survival analysis, lower expression levels of OPG were found to be associated with significantly better overall patient survival in our cohort. CONCLUSION: The corresponding prognostic and therapeutic potential is yet to be further investigated. Our data suggest that RANK, RANKL and OPG may potentially be used as novel prognostic markers for bone metastasis and provide new therapeutic targets in the treatment of breast cancer.

Melanoma accounts for approximately 79% of skin cancer-related deaths, and the receptor activator of NF-kappaB (RANK)-receptor activator of NF-kappaB ligand (RANKL) pathway has been shown to be involved in the migration and metastasis of epithelial tumor cells. In this study, we demonstrate that RANK was significantly increased in peripheral circulating melanoma cells, primary melanomas, and metastases from stage IV melanoma patients compared with tumor cells from stage I melanoma patients. However, upregulated RANK expression was not found in stage IV melanoma patients with bone metastases compared with stage IV melanoma patients without bone metastases, providing a possible explanation for the clinical observation that melanoma cells do not preferentially metastasize to bone tissue. Strikingly, RANK-expressing melanoma cells from peripheral blood, primary tumors, or metastases of stage IV patients coexpressed ATP-binding cassette (ABC) B5 and CD133, both markers characteristic of melanoma-initiating cells, suggesting a tumor stem cell-like phenotype. In support of this hypothesis, RANK-expressing melanoma cells showed a reduced Ki67 proliferation index compared with RANK(-) melanoma cells from the same patient and are able to induce tumor growth in immunodeficient mice. Together, our data demonstrate that RANK expression is increased in metastatic melanoma and highly upregulated on melanoma-initiating cells, suggesting that RANK might be involved in the development and maintenance of melanoma-initiating cells and possibly in metastatic spreading.

Receptor activator of NFkappaB ligand (RANKL), RANK, and osteoprotegerin (OPG) represent the key regulators of bone metabolism both in normal and pathological conditions, including bone metastases. To our knowledge, no previous studies investigated and compared RANK expression in primary tumors and in bone metastases from the same patient. We retrospectively examined RANK expression by immunohistochemistry in 74 bone metastases tissues from solid tumors, mostly breast, colorectal, renal, lung, and prostate cancer. For 40 cases, tissue from the corresponding primary tumor was also analyzed. Sixty-six (89%) of the 74 bone metastases were RANK-positive and, among these, 40 (59.5%) showed more than 50% of positive tumor cells. The median percentage of RANK-positive cells was 60% in primary tumors and metastases, without any statistically significant difference between the two groups (P=0.194). The same percentage was obtained by considering only cases with availability of samples both from primary and metastasis. Our study shows that RANK is expressed by solid tumors, with high concordance between bone metastasis and corresponding primary tumor. These data highlight the central role of RANK/RANKL/OPG pathway as potential therapeutic target not only in bone metastasis management, but also in the adjuvant setting.

BACKGROUND: Human non-small cell lung cancer (NSCLC) patients exhibit a high propensity to develop skeletal metastasis, resulting in excessive osteolytic activity. The RANKL/RANK/OPG system, which plays a pivotal role in bone remodeling by regulating osteoclast formation and activity, is of potential interest in this context. MATERIALS AND METHODS: Reverse transcriptase polymerase chain reaction, western blotting, and immunohistochemical analysis were used to examine the expression of RANKL, RANK, and OPG in human NSCLC cell lines with different metastatic potentials, as well as in 52 primary NSCLC samples and 75 NSCLC bone metastasis samples. In primary NSCLC patients, the expression of these proteins was correlated with clinicopathological parameters. Recombinant human RANKL and transfected RANKL cDNA were added to the PAa cell line to evaluate the promoter action of RANKL during the process of metastasis in vitro and in vivo. RESULTS: Up-regulated RANKL, RANK, and OPG expression and increased RANKL:OPG ratio were detected in NSCLC cell lines and in tumor tissues with bone metastasis, and were correlated with higher metastatic potential. The metastatic potential of NSCLC in vitro and in vivo, including migration and invasion ability, was significantly enhanced by recombinant human RANKL and the transfection of RANKL cDNA, and was impaired after OPG was added. The increased expression of RANKL and OPG correlated with tumor stage, lymph node metastasis, and distant metastasis. CONCLUSIONS: Differential expression of RANKL, RANK, and OPG is associated with the metastatic potential of human NSCLC to skeleton, raising the possibility that the RANKL/RANK/OPG system could be a therapeutic target for the treatment of metastatic NSCLC patients.

Prostate cancer (PCa) metastasis to bone is lethal and there is no adequate animal model for studying the mechanisms underlying the metastatic process. Here, we report that receptor activator of NF-kappaB ligand (RANKL) expressed by PCa cells consistently induced colonization or metastasis to bone in animal models. RANK-mediated signaling established a premetastatic niche through a feed-forward loop, involving the induction of RANKL and c-Met, but repression of androgen receptor (AR) expression and AR signaling pathways. Site-directed mutagenesis and transcription factor (TF) deletion/interference assays identified common TF complexes, c-Myc/Max, and AP4 as critical regulatory nodes. RANKL-RANK signaling activated a number of master regulator TFs that control the epithelial-to-mesenchymal transition (Twist1, Slug, Zeb1, and Zeb2), stem cell properties (Sox2, Myc, Oct3/4, and Nanog), neuroendocrine differentiation (Sox9, HIF1alpha, and FoxA2), and osteomimicry (c-Myc/Max, Sox2, Sox9, HIF1alpha, and Runx2). Abrogating RANK or its downstream c-Myc/Max or c-Met signaling network minimized or abolished skeletal metastasis in mice. RANKL-expressing LNCaP cells recruited and induced neighboring non metastatic LNCaP cells to express RANKL, c-Met/activated c-Met, while downregulating AR expression. These initially non-metastatic cells, once retrieved from the tumors, acquired the potential to colonize and grow in bone. These findings identify a novel mechanism of tumor growth in bone that involves tumor cell reprogramming via RANK-RANKL signaling, as well as a form of signal amplification that mediates recruitment and stable transformation of non-metastatic bystander dormant cells.

Receptor activator of NF-kappaB (RANK), RANK ligand (RANKL) and osteoprotegerin (OPG) play essential roles in bone metabolism. RANKL binds to RANK, which is expressed by osteoclasts whereas OPG acts as its decoy receptor blocking the RANK-RANKL interaction. OPG/RANK/RANKL are produced by variety of tissues including epithelial and mesenchymal cells. However, the role of RANKL/OPG in thyroid pathophysiology remains unclear. The aim of this study was to determine the expression pattern of RANK/RANKL/OPG in primary neoplastic thyroid lesions and in lymph node metastases. 27 specimens from total thyroidectomy were studied by immunohistochemistry: 9 papillary carcinomas (PC), 9 medullary carcinomas (MC), 9 macrovesicular adenomas (MA). Immunohistochemical evidence of RANKL was found in 30 % of MC, 22% of PC while RANKL has never been detected in PC. The expression of RANK is closely related to RANKL. OPG was restricted to the cytoplasm of epithelial in 1 MA and 1 MC. In contrast to pathological tissues, any expression of OPG/RANK/RANKL was detected in healthy thyroid tissue. This work reveals for the first time that OPG/RANK/RANKL are expressed in the pathological thyroid gland by follicular cells, by malignant parafollicular cells as well as in metastatic lymph node microenvironment. Thus OPG/RANK/RANKL molecular triad might play a role during pathogenesis of follicular and parafollicular tumors.