The function and molecular mechanism of CEP55 in anaplastic thyroid cancer.

OBJECTIVE The purpose of this study was to determine the role of centrosomal protein of 55 kDa (CEP55) in anaplastic thyroid cancer (ATC) and to further explore the mechanism, which might provide a new molecular marker for treatment of ATC. PATIENTS AND METHODS The expression level of CEP55 in clinical cases was tested by fluorescence quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Also, qRT-PCR assay was performed in different TC cell lines. The relationship between CEP55 expression and clinicopathological characteristics was statistically analyzed. Kaplan-Meier curve and Cox's proportional hazards regression model were performed in survival analysis. Further, Western blot assay was used to analyze the protein expression changes in PI3K/Akt pathway. RESULTS The expression level of CEP55 in TC tissues showed a noticeable upgrade, especially in ATC. In vitro, CEP55 expression was also increased in four kinds of TC cells, in which, the highest expression was found in ATC (TA-K) cells. The clinicopathological features, including lymph node metastasis, distant metastasis, and prognostic index were found to be correlated with the expression level of CEP55. Besides, the ATC patients with higher expression of CEP55 had a statistically worse overall survival (OS) time. In univariate analyses and multivariate analyses, the CEP55 level was an independent prognosis index of patients with ATC. In vitro study, CEP55 protein expression level was significantly reduced in si-CEP55-transfected TA-K cells. Notably, the downregulation of CEP55 could suppress the phosphorylation of PI3K and AKT. CONCLUSIONS This study found that CEP55 could promote ATC progression, and PI3K/AKT pathway might be the downstream target of its action. These results provided a new therapeutic direction for the treatment of ATC.