Hyperprolactinemia, usually caused by a pituitary lactotroph ational science. Sphingosine kinase 1 (SphK1), an oncogenic kinase, has been previously found to be elevated in various types of human cancer and play a role in tumor development and progression. Never- theless, the biological and clinical significance of SphK1 in thy- roid cancer is largely unknown. Here, we demonstrate that the expression of SphK1 is generally up-regulated in thyroid cancer and that its expression level is correlated with the degree of thyroid malignancy. Silencing SphK1 by specific RNA interfer- ence is able to suppress the proliferation of thyroid cancer cells, and SphK1 expression level is strongly associated with the ex- pression of proliferation cell nuclear antigen in thyroid cancer tissues. Of particular note is that depletion of SphK1 results in dephosphorylation of Akt and glycogen synthase kinase-3 and subsequent inactivation of B-catenin-T-cell factor/lymphoid en- hancing factor transcriptional activity. Hence, taken together, our study has identified SohK1 as a proproliferative oncogenic kinase, an Akt/glycogen synthase kinase-3 8/B-catenin activator, and probably a biomarker for thyroid cancer as well.
展开▼
