ABSTRACT
Epithelial-to-mesenchymal transition (EMT) plays a critical role in cancer metastasis,and is relevant to the inflammatory microenvironment.Lipopolysaccharide (LPS),a cell wall constituent of gram-negative bacteria,has been reported to induce EMT of cancer cells through TLR4 signal.We previously reported that LPS promoted metastasis of mesenchymallike breast cancer cells with high expression of cyclin D 1 b.However,the role of cyclin D1b in LPS-induced EMT has not been fully elucidated.In the present study,we described that cyclin D1b augmented EMT induced by LPS in MCF-7 breast cancer cells.Cyclin D1b markedly amplified integrin αvβ3 expression,which was further up-regulated under LPS stimulation.Our results showed ectopic expression of cyclin D1b promoted invasiveness of epithelial-like MCF-7 cells under LPS stimulation.Additionally,LPS-induced metastasis and EMT in MCF-7-D1b cells might depend on αvβ3 expression.Further exploration indicated that cyclin D1b cooperated with HoxD3,a transcription factor promoting αvβ3 expression,to promote LPS-induced EMT.Knockout of HoxD3 repressed LPS-induced EMT and αvβ3 over-expression in MCF-7 cells with high expression of cyclin D1b.Specifically,all these effects were in a cyclin D1a independent manner.Taken all together,LPS up-regulated integrin αvβ3 expression in MCF-7 cells with high expression of cyclin D 1b and induced EMT in breast cancer cells,which highlights that cyclin D1b may act as an endogenous pathway participating in exogenous signal inducing EMT in breast cancer cells.
ABSTRACT
Epithelial-to-mesenchymal transition (EMT) plays a critical role in cancer metastasis,and is relevant to the inflammatory microenvironment.Lipopolysaccharide (LPS),a cell wall constituent of gram-negative bacteria,has been reported to induce EMT of cancer cells through TLR4 signal.We previously reported that LPS promoted metastasis of mesenchymallike breast cancer cells with high expression of cyclin D 1 b.However,the role of cyclin D1b in LPS-induced EMT has not been fully elucidated.In the present study,we described that cyclin D1b augmented EMT induced by LPS in MCF-7 breast cancer cells.Cyclin D1b markedly amplified integrin αvβ3 expression,which was further up-regulated under LPS stimulation.Our results showed ectopic expression of cyclin D1b promoted invasiveness of epithelial-like MCF-7 cells under LPS stimulation.Additionally,LPS-induced metastasis and EMT in MCF-7-D1b cells might depend on αvβ3 expression.Further exploration indicated that cyclin D1b cooperated with HoxD3,a transcription factor promoting αvβ3 expression,to promote LPS-induced EMT.Knockout of HoxD3 repressed LPS-induced EMT and αvβ3 over-expression in MCF-7 cells with high expression of cyclin D1b.Specifically,all these effects were in a cyclin D1a independent manner.Taken all together,LPS up-regulated integrin αvβ3 expression in MCF-7 cells with high expression of cyclin D 1b and induced EMT in breast cancer cells,which highlights that cyclin D1b may act as an endogenous pathway participating in exogenous signal inducing EMT in breast cancer cells.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the inhibitory effect of recombinant polypeptide CH50 of fibronectin on invasion and angiogenesis of tumors, and analyze the possible molecular mechanism of the therapeutic effect of polypeptide CH50 on tumors.</p><p><b>METHODS</b>The tumor model was established by inoculation of H22 hepatocarcinoma cells in mice. The tumor gene therapy was performed by in vivo gene transfection with a method based on hydrodynamics to express polypeptide CH50. After treatment, the inhibitory effect on tumor invasion and angiogenesis was observed by histotology with HE staining of tumor tissues. The expresison of MMP-9 mRNA and protein at the edge of tumor tissue was evaluated by RT-PCR and gelatin zymography, respectively. RT-PCR was used to detect the expression of the related genes in H22 cells treated with polypeptide CH50. Cell adhesion assay was used to analyze the influence of polypeptide CH50 on the binding of cells to fibrinogen.</p><p><b>RESULTS</b>(1) Eukaryotic expression plasmid pCH510 was expressed in vivo in a non-targeting manner and produced a significant inhibitory effect on tumor growth. The therapy with polypeptide CH50 resulted in pronounced necrosis of tumor cells in pCH510 group, compared with that in control groups at histological level. (2) Polypeptide CH50 could inhibit the growth, invasion and angiogenesis of the tumor, and interfere the formation of new collateral circulation in the tumor. (3) The expression level of MMP-9 protein at the edge of tumor tissue was significantly decreased after treatment, especially the activation of pro-MMP-9 was inhibited significantly, whereas the expression level of MMP-9 mRNA was not influenced. (4) The expression of alphav, 33 and cdc2 mRNAs in H22 cells treated with polypeptide CH50 was down-regulated. (5) Cell adhesion assay manifested that polypeptide CH50 can affect the adhesion ability of H22 cells.</p><p><b>CONCLUSION</b>Polypeptide CH50 can inhibit tumor growth and angiogenesis by suppressing the functions of MMP-9 and integrin alphavbeta3.</p>
Subject(s)
Animals , Humans , Mice , CDC2 Protein Kinase , Genetics , Carcinoma, Hepatocellular , Metabolism , Pathology , Therapeutics , Cell Adhesion , Genetics , Physiology , Cell Line, Tumor , Fibronectins , Genetics , Physiology , Gene Expression Regulation, Neoplastic , Genetic Therapy , Methods , Integrin alphaVbeta3 , Genetics , Liver Neoplasms, Experimental , Metabolism , Pathology , Therapeutics , Matrix Metalloproteinase 9 , Genetics , Mice, Inbred BALB C , Neoplasm Invasiveness , Neoplasm Transplantation , Neovascularization, Pathologic , Genetics , Metabolism , Therapeutics , RNA, Messenger , Genetics , Random Allocation , Recombinant Proteins , Genetics , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Objective:To investigate the inhibitory effect of in vivo non-targeting transfection of recombinant fibronectin polypeptide CH50 against tumors and to study the related mechanisms.Methods:After inoculated with tumor cells, BALB/c mice were injected with CH50 plasmids,control plasmids,and normal saline separately.The growth of the tumor was observed;the expression of genes (such as B7-1,B7-H1 etc.) in tumor tissues was detected by RT-PCR;and the count of T lymphocytes in local tumor tissues was analyzed by flow cytometry.Results:The tumor growth was obviously suppressed by in vivo CH50 expression.The expression of genes (B7-1 and B7-H1) was up-regulated along with the growth of tumor.CH50 increased the ratios of B7-1/B7-H1 and B7-1/B7-DC and suppressed the up-regulation of IL-10 and TGF-?genes.The direct action of CH50 on H22 cells resulted in the down-regulatoin of TGF-?gene.The count of T lymphoeytes in tumor tissues of CH50 treatment group was significantly higher than that in other groups.Conclusion:Ex- pression of CH50 by non-targeting transfection can effectively inhibit the growth of tumor;the regulation of the immuno- regulatory genes in tumor mieroenvironment is an important part of the treatment mechanism of CH50.