Objective To investigate the effect of phosphatidylinositol 3-kinase(PI3K) inhibitor wortmannin on migration and invasion of human thyroid follicular carcinoma cell line CGTHW-1 and its mechanism.Methods MTT colorimetric assay was used to select the optimal concentration and time of giving wortmannin.CGTHW-1 cells used in present study were divided into control group and experimental group(cultured in the medium with or without blood serum).Cells of experimental group were treated with wortmannin,and that of control group were given no treatment.The migration and invasion ability of CGTHW-1 cells was detected by scratch test and Transwell chamber assay respectively.Microfilament fluorescence staining with fluorescein isothiocyanate(FITC)-labeled phalloidin was performed to observe the morphologic changes in CGTHW-1 cells.The expressions of Rac1 protein and mRNA in CGTHW-1 cells were examined by immunocytochemistry staining and semiquantitative RT-PCR.Results When CGTHW-1 cells were cultured in serum medium,the migrating speed of the cells slowed down,and the number of cells passing through the Transwell chamber reduced significantly after being treated with wortmannin in experimental group(13.8?3.03) than in control group(41.6?6.95,P0.05).Conclusions Wortmannin can effectively depress the migration and invasion of human thyroid follicular carcinoma cells,and the depression effect may be due to cytoskeleton rearrangement induced by inhibiting the expression of Rac1(the downstream molecule of PI3K).PI3K and Rac1 are probably potential targets for human thyroid cancer treatment,which may provide a theoretical evidence for the drug treatment of thyroid cancer.

Objective To investigate the effect of integrin β4 expression on the metastasis potential of human thyroid follicular cancer cells. Methods Metastasis potential was observed and grouped in human thyroid follicular cancer cell line, CGTHW-1 cells, depending on the cells' penetrating ability in artificial matrigel. The expression of integrin β4 mRNA and protein were determined by immunocytochemistry, Western blot, and semiquantitative RT-PCR. Results The mRNA and protein expressions of integrin β4 were significantly higher in cells with high metastasis potential [0.277 5 ±0.034 0 vs 0. 187 5 ±0.022 2 ( Immunohistochemistry ), 0. 099 7 ± 0.0185 vs 0.039 0±0.010 2(Western blot), 0.555 0±0. 101 2 vs 0.270 0±0.029 9(RT-PCR), all P＜0.01]. Conclusion Integrin β4 may play an important role in human thyroid cancer invasion. It seems probably to be a potential target for human thyroid cancer treatment.