title: Embryonic morphogen nodal promotes breast cancer growth and progression.
abstract: Breast cancers expressing human embryonic stem cell (hESC)-associated genes are more likely to progress than well-differentiated cancers and are thus associated with poor patient prognosis. Elevated proliferation and evasion of growth control are similarly associated with disease progression, and are classical hallmarks of cancer. In the current study we demonstrate that the hESC-associated factor Nodal promotes breast cancer growth. Specifically, we show that Nodal is elevated in aggressive MDA-MB-231, MDA-MB-468 and Hs578t human breast cancer cell lines, compared to poorly aggressive MCF-7 and T47D breast cancer cell lines. Nodal knockdown in aggressive breast cancer cells via shRNA reduces tumour incidence and significantly blunts tumour growth at primary sites. In vitro, using Trypan Blue exclusion assays, Western blot analysis of phosphorylated histone H3 and cleaved caspase-9, and real time RT-PCR analysis of BAX and BCL2 gene expression, we demonstrate that Nodal promotes expansion of breast cancer cells, likely via a combinatorial mechanism involving increased proliferation and decreased apopotosis. In an experimental model of metastasis using beta-glucuronidase (GUSB)-deficient NOD/SCID/mucopolysaccharidosis type VII (MPSVII) mice, we show that although Nodal is not required for the formation of small (<100 cells) micrometastases at secondary sites, it supports an elevated proliferation:apoptosis ratio (Ki67:TUNEL) in micrometastatic lesions. Indeed, at longer time points (8 weeks), we determined that Nodal is necessary for the subsequent development of macrometastatic lesions. Our findings demonstrate that Nodal supports tumour growth at primary and secondary sites by increasing the ratio of proliferation:apoptosis in breast cancer cells. As Nodal expression is relatively limited to embryonic systems and cancer, this study establishes Nodal as a potential tumour-specific target for the treatment of breast cancer.
authors.affiliation: Department of Anatomy & Cell Biology, University of Western Ontario, London, Ontario, Canada.
authors.forename: Daniela F
authors.initials: DF
authors.lastname: Quail
authors.forename: Guihua
authors.initials: G
authors.lastname: Zhang
authors.forename: Logan A
authors.initials: LA
authors.lastname: Walsh
authors.forename: Gabrielle M
authors.initials: GM
authors.lastname: Siegers
authors.forename: Dylan Z
authors.initials: DZ
authors.lastname: Dieters-Castator
authors.forename: Scott D
authors.initials: SD
authors.lastname: Findlay
authors.forename: Heather
authors.initials: H
authors.lastname: Broughton
authors.forename: David M
authors.initials: DM
authors.lastname: Putman
authors.forename: David A
authors.initials: DA
authors.lastname: Hess
authors.forename: Lynne-Marie
authors.initials: LM
authors.lastname: Postovit
mesh_terms: D030201:Activin Receptors, Type I / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D018450:Disease Progression; D005260:Female; D058851:GPI-Linked Proteins / Q000378:metabolism; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008175:Lung Neoplasms / Q000378:metabolism* / Q000556:secondary; D051379:Mice; D016688:Mice, Inbred NOD; D008819:Mice, Nude; D016513:Mice, SCID; D061206:Neoplasm Micrometastasis; D009363:Neoplasm Proteins / Q000378:metabolism; D009368:Neoplasm Transplantation; D055457:Nodal Protein / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D034741:RNA, Small Interfering / Q000235:genetics; D047368:Tumor Burden
chemical_list: D058851:GPI-Linked Proteins; D036341:Intercellular Signaling Peptides and Proteins; C526007:NODAL protein, human; D009363:Neoplasm Proteins; D055457:Nodal Protein; D034741:RNA, Small Interfering; C070636:TDGF1 protein, human; C498932:ACVR1B protein, human; C424205:ACVR1C protein, human; D030201:Activin Receptors, Type I