BACKGROUND: The cel density is one of the factors involved in the state of cel differentiation, and the effect of cel density on transforming growth factor-β1-induced epithelial-mesenchymal transition of HaCaT cells is stil unclear. OBJECTIVE: To observe the effect of cel density on transforming growth factor-β1-induced epithelial-mesenchymal transition of HaCaT cells. METHODS: HaCaT cells was seeded in 6-wel plates at low density of 103/cm2 and high density of 105/cm2 then treated by 2 μg/L transforming growth factor-β1 for 48 hours, thereafter observed the changes in cel morphology. The transcription levels of epithelial cadherin, tight junction protein-1, vimentin, neuronal-cadherin were detected by real-time PCR, and expression levels of epithelial cadherin and vimentin were detected by Western blot. RESULTS AND CONCLUSION: Cel gap of HaCaT cells grew larger after treated with transforming growth factor-β1 for 48 hours, and cel morphology was long spindle rather than polygonal in low-density group, while in high-density group without obvious morphological changes. The real-time PCR showed that the transcriptions of epithelial cel marker epithelial cadherin and tight junction protein-1 were suppressed when compared with the control group (P < 0.05), and the decreasing deree in the high-density group was higher than that in the low-density group (P <0.05), mesenchymal cel marker neuronal-cadherin and vimentin were upregulated in the high-density group and the low-density group when compared with the control group (P < 0.05), and there were no significant differences between high-density group and low-density group. Western blot results verified the changes of neuronal-cadherin and vimentin expression level. These results suggest that the high seeding density can inhibit transforming growth factor-β1-induced epithelial-mesenchymal transition of HaCaT cells.

Objective To explore the effect of SIRT1 gene silencing on the radiosensitivity of diffuse large B-cell lymphoma (DLBCL) cells.Methods Immunohistochemistry was used to measure the protein expression of SIRT1 in DLBCL tissues.Western blot was used to measure the expression of SIRT1 in DLBCL cell lines (OCI-Ly3,SU-DHL-2,and SU-DHL-4) and the immortalized B cell line HMy2.CIR.After SU-DHL-4 cells were transfected with si-SIRT1 and si-NC using Lipofectamine 2000,the expression of SIRT1 was determined by Western blot.MTT assay and colony-forming assay were used to assess the cell growth and colony formation ability of SU-DHL-4 cells treated with radiation.The group t-test or univariate analysis of variance was used for comparison between groups.Results The expression rate of SIRT1 in DLBCL tissues was 72.6%(103/140),which was significantly higher than that in reactive lymphoid hyperplasia (RLH) tissues (26.5%,8/25)(P=0.001).The SIRT1 expression was significantly higher in DLBCL cells than in HMy2.CIR cells (P=0.020).After SIRT1 gene silencing by si-SIRT1,the expression of SIRT1 was significantly reduced in SU-DHL-4 cells (P=0.008).Besides,SIRT1 gene silencing significantly reduced the growth rate and colony formation ability of SU-DHL-4 cells treated with radiation (P=0.030).Conclusions SIRT1 gene silencing enhances the radiosensitivity of DLBCL cells,providing a novel target for the radiotherapy of DLBCL.