Overexpression of the angiogenic tetrapeptide AcSDKP in human malignant tumors.

ABSTRACT

BACKGROUND: The natural tetrapeptide acetyl-Ser-Asp-Lys-Pro (AcSDKP), generated from thymosin beta4 following its cleavage by prolyl oligopeptidase (POP), is a physiological stimulator of angiogenesis. Because of the critical role of neovascularisation in tumor development, the expression of AcSDKP and the activity of POP were examined in different human solid malignancies. MATERIALS AND METHODS: The expression of AcSDKP and the activity of POP were evaluated in human blood samples and tissue specimens of thyroid goiter and thyroid papillary carcinoma as well as in commercial cancer tissue microarray. RESULTS: A significantly increased concentration of AcSDKP in intratumoral blood and enhanced tissular activity of POP were detected in cancer patients. The expression of AcSDKP in human breast, colon, head and neck, kidney, lung, skin, ovary and prostate cancer tissues was shown to be greater than that in normal tissues. CONCLUSION: AcSDKP and POP contribute to the malignant phenotype and these molecules are potentiel markers of cancer.