title: Runx2, p53, and pRB status as diagnostic parameters for deregulation of osteoblast growth and differentiation in a new pre-chemotherapeutic osteosarcoma cell line (OS1).
abstract: Osteosarcomas are the most prevalent primary bone tumors found in pediatric patients. To understand their molecular etiology, cell culture models are used to define disease mechanisms under controlled conditions. Many osteosarcoma cell lines (e.g., SAOS-2, U2OS, MG63) are derived from Caucasian patients. However, patients exhibit individual and ethnic differences in their responsiveness to irradiation and chemotherapy. This motivated the establishment of osteosarcoma cell lines (OS1, OS2, OS3) from three ethnically Chinese patients. OS1 cells, derived from a pre-chemotherapeutic tumor in the femur of a 6-year-old female, were examined for molecular markers characteristic for osteoblasts, stem cells, and cell cycle control by immunohistochemistry, reverse transcriptase-PCR, Western blotting and flow cytometry. OS1 have aberrant G-banded karyotypes, possibly reflecting chromosomal abnormalities related to p53 deficiency. OS1 had ossification profiles similar to human fetal osteoblasts rather than SAOS-2 which ossifies ab initio (P < 0.05). Absence of p53 correlates with increased Runx2 expression, while the slow proliferation of OS1 cells is perhaps attenuated by pRB retention. OS1 express mesenchymal stem cell markers (CD44, CD105) and differ in relative expression of CD29, CD63, and CD71 to SAOS-2. (P < 0.05). Cell cycle synchronization with nocodazole did not affect Runx2 and CDK1 levels but decreased cyclin-E and increased cyclin-A (P < 0.05). Xenotransplantion of OS1 in SCID mice yields spontaneous tumors that were larger and grew faster than SAOS-2 transplants. Hence, OS1 is a new osteosarcoma cell culture model derived from a pre-chemotherapeutic ethnic Chinese patient, for mechanistic studies and development of therapeutic strategies to counteract metastasis and deregulation of mesenchymal development.
authors.affiliation: Department of Orthopaedic Surgery, Musculoskeletal Research Laboratories, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Barry P
authors.initials: BP
authors.lastname: Pereira
authors.forename: Yefang
authors.initials: Y
authors.lastname: Zhou
authors.forename: Anurag
authors.initials: A
authors.lastname: Gupta
authors.forename: David T
authors.initials: DT
authors.lastname: Leong
authors.forename: Khin Zarchi
authors.initials: KZ
authors.lastname: Aung
authors.forename: Ling
authors.initials: L
authors.lastname: Ling
authors.forename: Robert W H
authors.initials: RW
authors.lastname: Pho
authors.forename: Mario
authors.initials: M
authors.lastname: Galindo
authors.forename: Manuel
authors.initials: M
authors.lastname: Salto-Tellez
authors.forename: Gary S
authors.initials: GS
authors.lastname: Stein
authors.forename: Simon M
authors.initials: SM
authors.lastname: Cool
authors.forename: Andre J
authors.initials: AJ
authors.lastname: van Wijnen
authors.forename: Saminathan S
authors.initials: SS
authors.lastname: Nathan
mesh_terms: D000293:Adolescent; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D044466:Asian People; D002113:Calcification, Physiologic / Q000502:physiology; D002453:Cell Cycle / Q000187:drug effects; D054337:Cell Dedifferentiation; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002648:Child; D002869:Chromosome Aberrations; D024042:Collagen Type I / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D051379:Mice; D016513:Mice, SCID; D015739:Nocodazole / Q000494:pharmacology; D010006:Osteoblasts / Q000473:pathology*; D015675:Osteocalcin / Q000378:metabolism; D012516:Osteosarcoma / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
chemical_list: D015703:Antigens, CD; D024042:Collagen Type I; D050659:Core Binding Factor Alpha 1 Subunit; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D019394:Ki-67 Antigen; C493709:RUNX2 protein, human; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D015675:Osteocalcin; D015739:Nocodazole