Gene expression profiling of alpha-radiation-induced rat osteosarcomas: identification of dysregulated genes involved in radiation-induced tumorigenesis of bone.
To better understand the molecular basis of radiation-induced osteosarcoma (OS), we performed global gene expression profiling of rat OS tumors induced by the bone-seeking alpha emitter (238)Pu, and the expression profiles were compared with those of normal osteoblasts (OB). The expressions of 72 genes were significantly differentially expressed in the tumors related to OB. These included genes involved in the cell adhesion (e.g., Podxl, Col18a1, Cd93, Emcn and Vcl), differentiation, developmental processes (e.g., Hhex, Gata2, P2ry6, P2rx5, Cited2, Osmr and Igsf10), tumor-suppressor function (e.g., Nme3, Blcap and Rrm1), Src tyrosine kinase signaling (e.g., Hck, Shf, Arhgap29, Cttn and Akap12), and Wnt/beta-catenin signaling (e.g., Fzd6, Lzic, Dkk3 and Ctnna1) pathways. Expression changes of several genes were validated by quantitative real-time RT-PCR analysis. Notably, all of the identified genes involved in the Wnt/beta-catenin signaling pathway were known or proposed to be negative regulators of this pathway and were downregulated in the tumors, suggesting the activation of beta-catenin in radiation-induced OS. By using immunohistochemical and immunoblot analyses, constitutive activation of the Wnt/beta-catenin signaling pathway in the tumors was confirmed by observing nuclear and/or cytoplasmic localization of beta-catenin and a decrease in its inactive (phosphorylated) form. Furthermore, we found a significant reduction in the levels of glycogen synthase kinase 3beta (GSK-3beta) protein in the tumors relative to OB. Taken together, these findings provide new insights into the molecular basis of radiation-induced OS.
Daino
Kazuhiro
K
Laboratoire de Cancérologie Expérimentale, iRCM, DSV, CEA, Fontenay-aux-Roses, France.
Ugolin
Nicolas
N
Altmeyer-Morel
Sandrine
S
Guilly
Marie-Noëlle
MN
Chevillard
Sylvie
S
D000512:Alpha Particles; D000818:Animals; D001859:Bone Neoplasms / Q000209:etiology / Q000235:genetics*; D045744:Cell Line, Tumor; D018450:Disease Progression; D015536:Down-Regulation; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D012516:Osteosarcoma / Q000209:etiology / Q000235:genetics*; D011832:Radiation Injuries / Q000209:etiology / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics / Q000528:radiation effects; D051153:Wnt Proteins / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
C495268:Ctnnb1 protein, rat; D051153:Wnt Proteins; D051176:beta Catenin; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D038362:Glycogen Synthase Kinase 3