title: The activities of Smad and Gli mediated signalling pathways in high-grade conventional osteosarcoma.
abstract: High-grade conventional osteosarcoma is a malignant tumour predominantly affecting adolescents and, despite multimodal intensive therapy, lethal for one third of the patients. Although there is currently detailed knowledge of normal skeletal development, this has not been integrated into research on the genesis of osteosarcoma. Recently we showed that the canonical Wnt pathway is not active in osteosarcoma and that its reactivation is disadvantageous to osteosarcoma cells. Since Wnt is regulating normal skeletogenesis together with other pathways, here we report on the activities of the bone morphogenic protein (BMP), the transforming growth factor beta (TGFβ) and the hedgehog (Hh) pathways in osteosarcoma. Human osteosarcoma samples (n=210), benign bone tumours of osteoblastic lineage called osteoblastoma (n=25) and osteosarcoma cell lines (n=19) were examined. For pathway activity luciferase transcriptional reporter assays and gene and protein expression analyses were performed. Immunohistochemical analysis of phosphorylated Smad1 and Smad2, the intracellular effectors of BMP and TGFβ, respectively, showed nuclear expression of both proteins in 70% of the osteosarcoma samples at levels comparable to osteoblastoma. Interestingly cases with lower expression showed significantly worse disease free survival. This may imply that drugs restoring impaired signalling pathways in osteosarcoma might change the tumour's aggressive clinical course, however targeted pathway modulation in vitro did not affect cell proliferation.
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Mohseny
authors.forename: Yongping
authors.initials: Y
authors.lastname: Cai
authors.forename: Marieke
authors.initials: M
authors.lastname: Kuijjer
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.forename: Brendy
authors.initials: B
authors.lastname: van den Akker
authors.forename: Carlos E
authors.initials: CE
authors.lastname: de Andrea
authors.forename: Rutger
authors.initials: R
authors.lastname: Jacobs
authors.forename: Peter
authors.initials: P
authors.lastname: ten Dijke
authors.forename: Pancras C W
authors.initials: PC
authors.lastname: Hogendoorn
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Cleton-Jansen
mesh_terms: D001859:Bone Neoplasms / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D045744:Cell Line, Tumor / Q000378:metabolism; D019902:Chondrocytes / Q000473:pathology; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics; D005784:Gene Amplification; D017930:Genes, Reporter; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000473:pathology; D062554:NAV1.5 Voltage-Gated Sodium Channel / Q000502:physiology; D060787:Neoplasm Grading; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D010011:Osteocytes / Q000473:pathology; D012516:Osteosarcoma / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D034622:RNA Interference; D015398:Signal Transduction / Q000502:physiology*; D051898:Smad1 Protein / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D051899:Smad2 Protein / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D060449:Wnt Signaling Pathway; D000071676:Zinc Finger Protein GLI1
chemical_list: C400551:GLI1 protein, human; D062554:NAV1.5 Voltage-Gated Sodium Channel; D009363:Neoplasm Proteins; C568320:SCN5A protein, human; C497399:SMAD1 protein, human; C497782:SMAD2 protein, human; D051898:Smad1 Protein; D051899:Smad2 Protein; D014157:Transcription Factors; D000071676:Zinc Finger Protein GLI1