Significance of Pituitary Tumor Transforming Gene 1 (PTTG1) in Prostate Cancer

Abstract

Recently, the pituitary tumor transforming gene 1 (PTTG1) has been suggested to be an oncogene. To investigate whether PTTG1 plays a positive role in the pathogenesis of prostate cancer, PTTG1 protein expression was examined in prostate tissue samples by immunohistochemistry. PTTG1 expression was detected in a high percentage of prostate cancer tissues (34/41, 82.9%), but to a much lesser extent in non-malignant tissues (5/14, 35.7%). To further confirm these results, the expression vectors containing either the PTTG1 or antisense-PTTG1 gene were transfected into a prostate cancer cell line, LNCaP, and the cell proliferation rate was studied, as well as tumorigenicity in the LNCaP cells expressing different levels of the PTTG1 protein. Ectopic PTTG1 gene expression promoted prostate cancer cell proliferation and tumorigenesis both in vitro and in nude mice. In contrast, down-regulation of PTTG1 led to suppression of tumor cell growth. These results suggest that PTTG1 may be a potential prognostic marker for prostate cancer and that the down-regulation of PTTG1 may be a therapeutic target in the suppression of prostate cancer growth.