This study aimed to explore Semaphrin4D（Sema4D） expression and clinical significance in non-small cell lung cancer（NSCLC）, and to define the roles and mechanisms of Sema4 D in regulating the malignant behaviors of...This study aimed to explore Semaphrin4D（Sema4D） expression and clinical significance in non-small cell lung cancer（NSCLC）, and to define the roles and mechanisms of Sema4 D in regulating the malignant behaviors of A549 cells by small interfering RNA（siRNA）. Firstly, immunohistochemistry revealed that Sema4 D was more frequently expressed in NSCLC than in lung benign lesion（P〈0.05） and its overexprssion was associated with low differentiation（P〈0.05）, poor pTNM staging（P〈0.05） and occurrence of lymph node（LN） metastasis（P〈0.05）. Endogenous Sema4 D expression was suppressed by Sema4 D siRNA in A549 cells overexpressing Sema4 D. Protein levels of Sema4 D, total Akt and p-Akt were examined by Western blotting. Cell proliferation, migration and invasion abilities were measured by MTT assay and Transwell assay respectively. Results showed that Sema4 D siRNA significantly suppressed phosphorylation of AKT in A549 cells, but it did not alter total AKT expression. In addition, efficient down-regulation of SemaD significantly inhibit cell proliferation（P〈0.05）, migration（P〈0.05） and invasion（P〈0.05） in A549 cells. These findings suggest that Sema4 D might serve as a reliable tool for early prediction of NSCLC poor prognosis. Sema4 D could play an important role in promoting tumor proliferation, migration and metastasis in the NSCLC, by influencing the Akt protein phosphorylation. Inhibition of Sema4 D may be a useful approach for the treatment of NSCLC.展开更多
Summary： Skeletal fluorosis is a chronically metabolic bone disease with extensive hyperostosis osteosclerosis caused by long time exposure to fluoride. Skeletal fluorosis brings about a series of abnormal changes of...Summary： Skeletal fluorosis is a chronically metabolic bone disease with extensive hyperostosis osteosclerosis caused by long time exposure to fluoride. Skeletal fluorosis brings about a series of abnormal changes of the extremity, such as joint pain, joint stiffness, bone deformity, etc. Differentiation and maturation of osteoblasts were regulated by osteoclasts via Sema4D/Plexin-B 1 signaling pathway. Furthermore, the differentiation and maturation of osteoclasts are conducted by osteoblasts via RANKL/RANK/OPG pathway. Both of these processes form a feedback circuit which is a key link in skeletal fluorosis. In this study, an osteoblast-osteoclast co-culture model in vitro was developed to illustrate the mechanism of skeletal fluorosis. With the increase of fluoride concentration, the expression level of Sema4D was decreased and TGF-β1 was increased continuously. OPG/RANKL mRNA level, however, increased gradually. On the basis of that, the inhibition of Sema4D/Plexin-B1/RhoA/ROCK signaling pathway caused by fluoride promoted the level of TGF-β1 and activated the proliferation of osteoblasts. In addition, osteroprotegerin （OPG） secreted by osteoblasts was up-regulated by fluoride. The competitive combination of OPG and RANKL was strengthened and the combination of RANKL and RANK was hindered. And then the differentiation and maturation of osteoclasts were inhibited, and bone absorption was weakened, leading to skeletal fluorosis.展开更多
基金supported by the National Natural Science Foundation of China(No.30973473)
文摘This study aimed to explore Semaphrin4D（Sema4D） expression and clinical significance in non-small cell lung cancer（NSCLC）, and to define the roles and mechanisms of Sema4 D in regulating the malignant behaviors of A549 cells by small interfering RNA（siRNA）. Firstly, immunohistochemistry revealed that Sema4 D was more frequently expressed in NSCLC than in lung benign lesion（P〈0.05） and its overexprssion was associated with low differentiation（P〈0.05）, poor pTNM staging（P〈0.05） and occurrence of lymph node（LN） metastasis（P〈0.05）. Endogenous Sema4 D expression was suppressed by Sema4 D siRNA in A549 cells overexpressing Sema4 D. Protein levels of Sema4 D, total Akt and p-Akt were examined by Western blotting. Cell proliferation, migration and invasion abilities were measured by MTT assay and Transwell assay respectively. Results showed that Sema4 D siRNA significantly suppressed phosphorylation of AKT in A549 cells, but it did not alter total AKT expression. In addition, efficient down-regulation of SemaD significantly inhibit cell proliferation（P〈0.05）, migration（P〈0.05） and invasion（P〈0.05） in A549 cells. These findings suggest that Sema4 D might serve as a reliable tool for early prediction of NSCLC poor prognosis. Sema4 D could play an important role in promoting tumor proliferation, migration and metastasis in the NSCLC, by influencing the Akt protein phosphorylation. Inhibition of Sema4 D may be a useful approach for the treatment of NSCLC.
基金suppooted by the National Natural Science Foundation of China(No.81372941)
文摘Summary： Skeletal fluorosis is a chronically metabolic bone disease with extensive hyperostosis osteosclerosis caused by long time exposure to fluoride. Skeletal fluorosis brings about a series of abnormal changes of the extremity, such as joint pain, joint stiffness, bone deformity, etc. Differentiation and maturation of osteoblasts were regulated by osteoclasts via Sema4D/Plexin-B 1 signaling pathway. Furthermore, the differentiation and maturation of osteoclasts are conducted by osteoblasts via RANKL/RANK/OPG pathway. Both of these processes form a feedback circuit which is a key link in skeletal fluorosis. In this study, an osteoblast-osteoclast co-culture model in vitro was developed to illustrate the mechanism of skeletal fluorosis. With the increase of fluoride concentration, the expression level of Sema4D was decreased and TGF-β1 was increased continuously. OPG/RANKL mRNA level, however, increased gradually. On the basis of that, the inhibition of Sema4D/Plexin-B1/RhoA/ROCK signaling pathway caused by fluoride promoted the level of TGF-β1 and activated the proliferation of osteoblasts. In addition, osteroprotegerin （OPG） secreted by osteoblasts was up-regulated by fluoride. The competitive combination of OPG and RANKL was strengthened and the combination of RANKL and RANK was hindered. And then the differentiation and maturation of osteoclasts were inhibited, and bone absorption was weakened, leading to skeletal fluorosis.
