Thymosin beta-4 is Differentially Expressed in Human Osteosarcomas

Thymosin-Beta 4 (TB-4), which was considered a thymic hormone, is a Gactin sequestering peptide with multiple functions that include chemotaxis, angiogenesis, induction of metallo-proteinases and inhibition of inflammation. Reports using deoxyribonucleic acid (DNA)-array methodology show that increased TB-4 expression correlates with cancer. The up-regulation of TB-4 expression was significantly associated with metastasis using contemporary DNA chip microarray analysis. The purpose of this study was to determine if TB-4 was expressed in human osteosarcomas. Northern blot analysis was used to detect TB-4 expression in three human osteosarcoma cell lines (MG-63, SaOS2 and U2OS) and 13 primary human osteosarcoma tissue samples. The expression of cell adhesion molecules, including beta-catenin, alpha- and beta-tubulin, Ncadherin, E-cadherin and P-cadherin, was also detected by Western blot analysis. TB-4 expression varied in three osteosarcoma cell lines as well as in primary osteosarcoma specimens. High expression of TB-4 was related to pulmonary metastasis, local recurrence and young age. β-catenin was also highly expressed in patients with pulmonary metastasis at the time of initial diagnosis. In addition, there was an inverse relationship between the expressions of β-catenin and f3-tubulin. The expression of. β-catenin was more in line with Tb-4. In conclusion, TB-4 was differentially expressed in human osteosarcomas and high expression was associated with poor outcome. Longer follow-up of the oncological results of these patients is required to establish a relationship between expression and metastasis. In addition, more work is needed to establish a relationship between the expression of β-catenin and β-tubulin and predicting prognosis.