Department of Urology, The First Affiliated Hospital of Tsinghua University, No.6 Jiuxianqiao No.1Street, Chaoyang District, Beijing 100016, China


Introduction: Bladder cancer is one of the most common malignancies in the genitourinary system, and the incidence tends to increase year by year. Despite tremendous progress in diagnosis and traditional treatment, the prognosis of patients, especially locally advanced or muscle-invasive bladder cancer remains poor. Currently many molecular biomarkers are considered to be assoisated with the occurrence of bladder cancer. The Speckle-type POZ protein, SPOP, is an E3 ubiquitin ligase adaptor, and it is found to inhibit oncogenic signaling in other cancers. However, the molecular mechanisms in bladder cancer are less reported.

Methods: In this study, we characterized the expression of SPOP in 46 pairs of bladder cancer tissues and adjacent tissues by immunohistochemical staining and Western blotting. The relationship between SPOP expression and clinicalpathologic factors was analyzed. Transfected bladder cancer cell lines T24 were used in cell viability, migration and wound healing assays to inves- tigate the role of tumor suppression mechanism.

Results: Immunohistochemical staining of SPOP can be detected in bladder cancer tissues but much less than adjacent bladder tissues (P < 0.01). High SPOP expression is negatively correlated with lymph node metastasis, poor histological differen- tiation, and tumor malignancy according to TNM staging. In vitro inhibition of SPOP markedly promoted cell viability, migration and inva- sion in vitro in bladder cancer cell lines. Likewise, overexpression of SPOP inhibited cell viability, migration and prolif- eration.

Conclusions: Our findings indicate that SPOP might act as a tumor suppressor and may have potential use as novel bio- marker of bladder cancer, and can provide an alternative strategy for developing therapeutic agents of bladder cancer in future.

Keywords: SPOP, Tumor suppressor, bladder cancer.


SPOP, Tumor suppressor, bladder cancer.