Inhibition of epithelial-mesenchymal transition in A549 cell by transfected Napsin A / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Epithelial-mesenchymal transition is a cellular process characterized by the loss of cell adhesion, inhibition of E-cadherin expression, and increased cell mobility. Cells without Napsin A are susceptible to transition. Further studies are required to investigate whether this transition can be reversed by restoration of Napsin A.</p><p><b>METHODS</b>A Napsin A expression vector PLJM1-Napsin A plasmid was constructed and then transfected into the epithelial cell line A549 by lentivirus transfection to obtain A549-PLJM1-Napsin A cell line. Cell proliferation was assayed by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide and cell cycle was measured by flow cytometry. The E-cadherin, type I collagen, and focal adhesion kinase mRNA level was detected by reverse transcription-polymerase chain reaction. The Napsin A, E-cadherin, type I collagen, and focal adhesion kinase protein level in A549 cells was detected by Western blotting.</p><p><b>RESULTS</b>Transforming growth factor-b1 induced epithelial-mesenchymal transition in A549 cells, as demonstrated by significant reduction of E-cadherin mRNA and protein levels (P < 0.01) as well as up-regulation of type I collagen (P < 0.01). Transfection of Napsin A in A549 cells can partially block the transforming growth factor-b1-regulated expression of E-cadherin and type I collagen (P < 0.01). In addition, transforming growth factor-b1-induced cell proliferation was inhibited by Napsin A (P < 0.01). Further study demonstrated that Napsin A caused G(0)/G(1) arrest and inhibited the expression of focal adhesion kinase (P < 0.01), a key protein in the integrin signaling pathway, in the in vitro epithelial-mesenchymal transition model.</p><p><b>CONCLUSIONS</b>Sustained Napsin A expression in A549 cells can inhibit the transforming growth factor-b1-induced epithelial-mesenchymal transition. This may be due to the Napsin A-mediated inhibition of focal adhesion kinase expression and integrin signaling pathway.</p>

Preparation of 131I-K237 and the experimental study on targeting therapy in nude mice bearing human lung cancer / 中华核医学杂志

Objective To establish the radiolabeling method for peptide K237 with 131I and investigate the biodistribution and therapeutic efficacy of 131I-K237 on nude mice bearing human lung cancer.Methods Iodogen method was used for labeling K237. The bioactivity of 131I-K237 was tested by human umbilical vein endothelial cell ( HUVEC ) proliferation inhibitory assay and the affinity of 131I-K237 was examined by competition binding studies. Twenty-five mice were divided into five groups randomly, including physiologic saline (group 1), K237 (40 μg) (group 2), 131I ( 11. 1 MBq) (group 3), 131I-K237 (K237 40 μg, 11. 1 MBq) intravenously ( group 4), and 131I-K237 ( K237 40 μg, 11.1 MBq) intratumorally (group 5). Injections were repeated at 15 d after the first injection. The tumor growth inhibition rate was calculated. Student's t-test and analysis of variance (ANOVA) were used for testing significant differences of data. Results The inhibition rate of HUVEC proliferation had no significant difference between radiolabeled K237 and unlabeled K237 ( (73.69 ± 5.36) % vs ( 62.68 ± 3.83 ) %, t = 1.67, P ＞ 0.05 ). The growth of transplanted lung cancer was inhibited by 75. 01 % in group 4, 78.99% in group 5, 31.15% in group 2 and 12.61% in group 3, respectively. The average tumor volume of groups 4 and 5 were significantly smaller than that of groups 1,2, and 3 ( F = 15. 233 and 13.611, respectively, P ＜0. 01 ). Conclusion 131I-K237 can be readily radiolabeled and it can effectively inhibit the growth of tumor in nude mice bearing human lung cancer.