Comparative proteomic analysis of human osteosarcoma and SV40-im-mortalized normal osteoblastic cell lines

Aim:Comparative proteomics provide a powerful approach in screening for alter-ations in protein levels and post-translational modifications that are associatedwith tumors.In the present study,we aimed to identify candidate biomarkers todistinguish osteosarcoma (OS) cells from normal osteoblastic cells.Methods:Weemployed 3OS cell lines (U2OS,IOR/OS9,and SaOS-2),and used the SV40-immor-talized normal osteoblastic cell line (hFOB 1.19) as the control.The differentialprotein levels in OS and osteoblastic cells were identified using 2-D gel electro-phoresis followed by matrix-assisted laser desorption/ionization-time of flightmass spectrometry analyses.Two proteins of interest,the levels of which weresignificantly increased in OS cells,were further characterized by Western blotanalyses.Results:Twenty-six proteins were identified,the expression level ofwhich was either significantly increased or decreased in the OS cells as comparedto the control cells.The expression level of the activator of 90 kDa shock proteinATPase homolog 1 (AHA1),was enhanced 12.4-,24.1-,and 23.8-fold in SaOS-2,IOR/OS9,and U2OS cells,respectively,and the level of the stomatin-like protein 2(SLP-2) was increased by 10.4-and 7.8-fold in IOR/OS9 and U2OS cells,respectively,as compared to normal osteoblastic cells.Those observations were confirmed byWestern blot analyses.Conclusion:A differential proteomic analysis was suc-cessfully used to identify AHA 1 and SLP-2 that were significantly overproducedin OS cells as compared to normal osteoblastic cells,suggesting that those pro-teins among others may be effective biomarker candidates for the identification ofOS cells.