Expression of WW domain-containing protein 2 is correlated with pathological grade and recurrence of glioma.

OBJECTIVE: WW domain-containing protein 2 (WWP2) is an E3 ubiquitin ligase, which belongs to the NEDD4-like protein family. Recently, it is reported to play a key role in tumorigenesis and development of tumors such as prostate and lung cancer. However, there has been not related report on glioma until now. The aim of this study is to detect the expression of WWP2 and analyze its correlation to the pathological grade and tumor recurrence in patients with glioma. MATERIALS AND METHODS: Western blot and immunohistochemistry were separately used to detect the expression of WWP2 protein in 31 brain glioma tissue samples and 80 brain glioma paraffin specimens. The method of Kaplan-Meier was used to analyze the correlation between the WWP2 expression and glioma recurrence. RESULTS: The protein expression level of WWP2 in glioma tissue was significantly higher than that in nontumorous brain tissue (P < 0.05), and the protein expression level of WWP2 in high-grade glioma (Grade III-IV) was significantly higher than that in low-grade glioma (Grade I-II) (P < 0.05). Kaplan-Meier analysis indicated that the patients with high WWP2 expression had significantly shorter tumor recurrence time than the patients with low WWP2 expression (P < 0.05). CONCLUSION: Our study suggests that WWP2 may play a role in the genesis and development of glioma; it may be a potential biomarker to predict pathological grade and tumor recurrence in patients with glioma.

ß-transducin repeat-containing E3 ubiquitin protein ligase inhibits migration, invasion and proliferation of glioma cells.

ß-transducin repeat-containing E3 ubiquitin protein ligase (ß-TrCP) serves as the substrate recognition subunit for the Skp1-Cullin1-F-box protein E3 ubiquitin ligase, which recognizes the double phosphorylated DSG (X)2+nS destruction motif in various substrates that are essential for numerous aspects of tumorigenesis and regulates several important signaling pathways. However, the biological significance of ß-TrCP in glioma progression remains largely unknown. A previous study by the authors demonstrated that the levels of ß-TrCP protein expression in brain glioma tissues were significantly lower compared with non-tumorous tissues and that higher grades of gliomas exhibited lower levels of ß-TrCP expression in comparison with lower glioma grades. In addition, low ß-TrCP expression was associated with poor prognosis in patients with glioma. Subsequently, the present study aimed to investigate the effect of ß-TrCP on migratory, invasive and proliferative abilities of glioma cells. ß-TrCP plasmids were transfected into cultured U251 and U87 glioma cells, and changes in migration, invasion and proliferation were analyzed using wound healing, Transwell and EdU assays. It was identified that the overexpression of ß-TrCP inhibited migration, invasion and proliferation in glioma cells. In summary, these results indicate that ß-TrCP may serve a protective role against the progression of glioma by suppressing cell migration, invasion and proliferation. The potential mechanism of ß-TrCP I glioma cells requires additional investigation.

Expression of ß-transducin repeat-containing E3 ubiquitin protein ligase in human glioma and its correlation with prognosis.

ß-transducin repeat-containing E3 ubiquitin protein ligase (ß-TrCP) targets a number of substrates essential for specific aspects of tumorigenesis. In addition, ß-TrCP regulates various important signaling pathways. As ß-TrCP is involved in regulating the ubiquitination and degradation of multiple oncogenes and tumor suppressors, the function of ß-TrCP varies between cancer types. At present, the association between ß-TrCP expression and clinicopathological factors in glioma is unknown. Therefore, the current study used western blotting and immunohistochemistry to investigate the expression of ß-TrCP protein in glioma tissue specimens. It was identified that ß-TrCP protein expression levels were significantly lower in glioma compared with non-tumorous human brain tissues. Furthermore, the higher the grade of glioma, the lower the level of ß-TrCP expression. Kaplan-Meier analysis demonstrated that patients with low ß-TrCP expression experienced significantly worse overall survival compared with patients with high ß-TrCP expression. The results indicate that downregulation of ß-TrCP may be associated with poor survival in patients with glioma. Together, the current data indicates that ß-TrCP may be applied as a useful indicator of glioma prognosis and may serve as an anticancer therapeutic target for glioma, however further investigation is required.