* Statistically

significant (P < 0.05, t-test) as compared with NP69 group. The values are expressed as means ± SD of six repeated experiments. TGF-β type II receptor and Smads in CNE2 cells To investigate alterations of the TGF-β/Smad signaling pathway in CNE2 cells, the TGF-β type II receptor (TβR-II) and the TGF-β/Smad signaling components-Smads signal transduction were explored at both mRNA level and protein level by real time RT-PCR, using specific primers according to GenBank database sequences, western blotting and immunocytochemical analysis, respectively. First, we investigated TβR-II mRNA expression which is an upstream signaling partner of the TGF-β/Smad signaling pathway, while the normal nasopharyngeal epithelial cells were used as control. Under the same culture conditions, we found that TβR-II was significantly up-regulated in CNE2 cells compared to the levels observed in NP69 cells. We further evaluated the Smads which are the principal Selleckchem OSI 906 intracellular components of the TGF-β signaling pathway, and the results showed that Smad2, Smad3 and Smad4 mRNA all increased significantly in CNE2 cells compared to the levels observed in NP69 cells. However, the mRNA level of smad7, known as an inhibitory Smad, remained at same level as that observed for the

normal nasopharyngeal cells (Figure 2A, 2B). To investigate the protein expression of the TβR-II receptor and Smads, buy FK228 western blotting was performed in NP69 and CNE2 cells. We found that Smad2, Smad3, Smad4 and TβR-II were also up-regulated in protein levels, but Smad7 protein level were no different compared to that observed in NP69 cells (Figure 3). To further see more localize the expression of the above signaling components in CNE2 cells, immunocytochemical staining was conducted. A positive staining of TβR-II was found in most CNE2 cells,

and the cell membrane was the main localization of the protein. The positive staining of Smad2, Smad3 and Smad4 was found in regions of both the cytoplasm and nucleus, while the staining of Smad7 was mainly in the nucleus (Figure 4A). Figure 2 The mRNA level of the TGF-β receptor II and the Smads in CNE2 and NP69 cells. (A) Expression level of the TβRII, Smad 2, Smad 3, Smad 4, Smad 7 in CNE2 cells and NP69 cells by RT-PCR using specific primers. β-actin was used as a control and was further to normalize. (B) Bar diagram of the TβRII, Smad 2, Smad 3, Smad 4, Smad 7 mRNA level from densitometric measurement of three real-time quantitative PCR from three separate treatments. * Statistically significant (P < 0.05, t-test) as compared with NP69 group.** Statistically significant (P < 0.01, t-test) as compared with NP69 group. Figure 3 The expression of the TGF-β receptor II and the Smads in CNE2 and NP69 cells. Expression level of the TβRII, Smad 2, Smad 3, Smad 4, Smad 7 in CNE2 cells and NP69 cells by western blot. Actin was used as a protein loading control and was further to normalize.