Comparative proteomics analysis of human osteosarcomas and benign tumor of bone

We conducted comparative proteomic analysis of osteosarcoma, with hopes of identifying the specific protein markers of osteosarcoma and improve the understanding of tumorigenesis and progression of osteosarcoma. Proteins extracted from osteosarcoma tissue and benign bone tumors, including osteoblastoma, chondroblastoma, and giant cell tumor of bone, were examined using two-dimensional gel electrophoresis followed by mass spectrometry analysis and database searches. We also validated the expression levels of interesting proteins by Western blotting assay and immunohistochemical staining. Intensity alterations of 30 spots were detected in osteosarcoma, and 18 of these spots were finally identified, including 12 up-regulated proteins and 6 down-regulated ones. The up-regulated proteins include VIM, TUBA1C, ZNF133, EZR, ACTG1, TF, and so on. The six down-regulated proteins include ADCY1, ATP5B, TUBB, RCN3, ACTB, and YWHAZ. Subsequent immunohistochemical staining and Western blotting assay for TUBA1C and ZNF133 in osteosarcoma samples confirmed the observation obtained by proteomic analysis. Our results suggest that these identified proteins may be potential biomarkers for osteosarcoma tumorigenesis and therapeutics. Aberrant expression of cytoskeletal- and microtubule-associated proteins in osteosarcoma may provide an advantage for tumor invasion and metastasis by affecting the stability of microtubule, which consequently influences the prognosis of patients.