title: Nitric Oxide Up-Regulates RUNX2 in LNCaP Prostate Tumours: Implications for Tumour Growth In Vitro and In Vivo.
abstract: Aberrant expression of the transcription factor RUNX2 in prostate cancer has a number of important consequences including increased resistance to apoptosis, invasion and metastasis to bone. We previously demonstrated that hypoxia up-regulated RUNX2 in tumour cells, which in turn up-regulated the anti-apoptotic factor Bcl-2. Here, we investigate the impact of nitric oxide (NO) on RUNX2 and Bcl-2 expression in prostate cancer and further, how RUNX2 over-expression can impact tumour growth, angiogenesis and oxygenation in vivo. The effect of NO levels on RUNX2 and thus Bcl-2 expression was examined in prostate cancer cells in vitro using methods including gene and protein expression analyses, nitrite quantitation, protein-DNA interaction assays (ChIP) and viability assays (XTT). The effect of RUNX2 over-expression on tumour physiology (growth, oxygenation and angiogenesis) was also assessed in vivo using LNCaP xenografts. A low (but not high) concentration of NO (10 μM) induced expression of RUNX2 and Bcl-2, conferring resistance to docetaxel. These effects were induced via the ERK and PI3K pathways and were dependent on intact AP-1 binding sites in the RUNX2 promoter. RUNX2 over-expression in LNCaP tumours in vivo decreased the time to tumour presentation and increased tumour growth. Moreover, these tumours exhibited improved tumour angiogenesis and oxygenation. Low levels of NO increase expression of RUNX2 and Bcl-2 in LNCaP prostate tumour cells, and in vivo up-regulation of RUNX2 created tumours with a more malignant phenotype. Collectively, our data reveals the importance of NO-regulation of key factors in prostate cancer disease progression.
authors.affiliation: Biomedical Science Research Institute, University of Ulster, Coleraine, Londonderry, Northern Ireland.
authors.forename: Heather
authors.initials: H
authors.lastname: Nesbitt
authors.affiliation: Department of Biochemistry and Vermont Cancer Center, University of Vermont College of Medicine, Burlington, Vermont.
authors.forename: Gillian
authors.initials: G
authors.lastname: Browne
authors.affiliation: Biomedical Science Research Institute, University of Ulster, Coleraine, Londonderry, Northern Ireland.
authors.forename: Katie M
authors.initials: KM
authors.lastname: O'Donovan
authors.affiliation: Bone Biology Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia.
authors.forename: Niall M
authors.initials: NM
authors.lastname: Byrne
authors.affiliation: Biomedical Science Research Institute, University of Ulster, Coleraine, Londonderry, Northern Ireland.|Axis Bioservices Ltd., Research Laboratory, Coleraine, Londonderry, Northern Ireland.
authors.forename: Jenny
authors.initials: J
authors.lastname: Worthington
authors.affiliation: Biomedical Science Research Institute, University of Ulster, Coleraine, Londonderry, Northern Ireland.
authors.forename: Stephanie R
authors.initials: SR
authors.lastname: McKeown
authors.affiliation: Biomedical Science Research Institute, University of Ulster, Coleraine, Londonderry, Northern Ireland.
authors.forename: Declan J
authors.initials: DJ
authors.lastname: McKenna
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D050659:Core Binding Factor Alpha 1 Subunit / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D055785:Gene Knockdown Techniques; D064593:Heterografts; D006801:Humans; D061986:MCF-7 Cells; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D009569:Nitric Oxide / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D015854:Up-Regulation
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D034741:RNA, Small Interfering; C493716:Runx2 protein, mouse; D009569:Nitric Oxide