title: Importance of osteoprotegrin and receptor activator of nuclear factor κB in breast cancer response to hepatocyte growth factor and the bone microenvironment in vitro.
abstract: Osteoprotegrin (OPG), receptor activator of nuclear factor κB (RANK) and RANK ligand (RANKL) are signal transducers which have pleiotropic actions. Each tumour necrosis factor receptor superfamily member has unique structural attributes which directly couples them to signalling pathways involved in cell proliferation, differentiation and survival. Previous studies have clinically linked OPG, RANK and RANKL to increasing tumour burden, metastatic bone involvement and estrogen status. This study aimed to establish the potential implications of targeting endogenously produced OPG and RANK in the osteotropic breast cancer cell line MDA-MB‑231 in vitro. Subsequently this study also aimed to explore the potential links between these molecules with regards to hepatocyte growth factor (HGF) signalling and extracted bone proteins (BME). OPG and RANK expression was successfully suppressed using hammerhead ribozyme technology. Subsequently effects were explored in MDA-MB‑231 cell proliferation, matrix adhesion, migration and invasion in vitro function assays. Reduced OPG expression resulted in increased breast cancer cell migration and invasion. These increases, particularly invasion, appeared to however be reduced under the influence of the exogenous stimuli (HGF and BME). In contrast, suppression of RANK in MDA-MB‑231 breast cancer cells resulted in decreased cancer cell proliferation, matrix-adhesion, motility and invasion with little cumulative effect being noted after the addition of exogenous stimuli. The complexity of the bone environment underpins the vast number of soluble factors and signalling pathways which can influence osteotropic cancer behaviour and progression. Further work into elucidating all the pathways affected could potentially lead to better identification of those patients most at risk.
authors.affiliation: Cardiff China Medical Research Collaborative, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
authors.forename: Sioned
authors.initials: S
authors.lastname: Owen
authors.affiliation: Cardiff China Medical Research Collaborative, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Sanders
authors.affiliation: Section of Oncology and Palliative Medicine, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
authors.forename: Malcolm D
authors.initials: MD
authors.lastname: Mason
authors.affiliation: Cardiff China Medical Research Collaborative, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK.
authors.forename: Wen G
authors.initials: WG
authors.lastname: Jiang
mesh_terms: D001842:Bone and Bones / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism*; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D018450:Disease Progression; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D009362:Neoplasm Metastasis; D053244:Osteoprotegerin / Q000378:metabolism*; D053245:RANK Ligand / Q000378:metabolism*; D016337:RNA, Catalytic / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D016337:RNA, Catalytic; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D017228:Hepatocyte Growth Factor