ABSTRACT
<p><b>OBJECTIVE</b>To investigate effect of AP-1 and Ets binding site adjacent to matrix metalloproteinase-9 (MMP-9) promoter on activation of MMP-9 transcription of nasopharyngeal carcinoma cells transfected with EBV-encoded latent membrane protein 1 (LMP1), and to ascertain if cross-talk between c-Jun and Ets1 is involved in LMP1-regulating expression of MMP-9.</p><p><b>METHODS</b>Site-directed mutagenesis technique was used to establish a series of mutants, including MMP-9-CAT-Ets(-540)mt, MMP-9-CAT-AP-1(-533)mt and MMP-9-CAT-AP-1(-533)/Ets(-540)mt. After the mutants were transfected into LMP1-expressing NPC HNE2 cells regulated by Tet-on system (pTet-on-LMP1 HNE2), CAT activity of these mutants were assayed with induction of LMP1. With blockade of c-Jun or Ets1 antisense oligonucleotides, the activity of MMP-9 induced by LMP1 was assayed with gelatin zymography.</p><p><b>RESULTS</b>The CAT activity of MMP-9-Ets(-540)mt-CAT, MMP-9-AP-1(-533)mt-CAT, MMP-9-AP-1(-533)/Ets(-540) mt-CAT decreased significantly compared to MMP-9-CAT wt. After blockade with c-Jun or Ets1 antisense oligonucleotides, activity of MMP-9 induced by LMP1 decreased significantly, especially with combined blockade of c-Jun and Ets1.</p><p><b>CONCLUSION</b>The results suggest that transcription factor AP-1 and Ets play an crucial role in activation of MMP-9 transcription induced by LMP1, and cross-talk between c-Jun/Ets1 is involved in expression of MMP-9 mediated by LMP1.</p>
Subject(s)
Humans , Herpesvirus 4, Human , Genetics , Matrix Metalloproteinase 9 , Genetics , Nasopharyngeal Neoplasms , Metabolism , Virology , Proto-Oncogene Protein c-ets-1 , Genetics , Proto-Oncogene Proteins c-jun , Genetics , Transfection , Tumor Cells, Cultured , Viral Matrix Proteins , GeneticsABSTRACT
<p><b>OBJECTIVE</b>To elucidate the interference effect of Epigallocatechin-3-Gallate (EGCG) on targets of Activator Protein-1 (AP-1) signal transduction pathway activated by EB virus encoded latent membrane protein 1 in nasopharyngeal carcinoma (NPC) cell lines.</p><p><b>METHODS</b>Survival rate of cells was determined by MTT assay. AP-1 and CyclinD1 activation were analyzed by promoter luciferase reporter system. Nuclear translocation of JNK was analyzed by indirect immunofluorescence. Protein expression and phosphorylation were observed by Western blot.</p><p><b>RESULTS</b>EGCG inhibited the survival of CNE1 and CNE-LMP1 cells and the activity of AP-1 caused by LMP1 in CNE-LMP1 cells. EGCG also inhibited the nuclear translocation of JNK and the phosphorylation of c-Jun. It also inhibited cyclinD1 promoter activity and cyclinD1 expression.</p><p><b>CONCLUSION</b>EGCG inhibits AP-1, JNK, c-Jun and cyclinD1 which are key targets on AP-1 signal transduction pathway. The results may explain the molecular mechanism of action of EGCG against nasopharyngeal carcinoma.</p>
Subject(s)
Humans , Carcinoma, Squamous Cell , Metabolism , Pathology , Virology , Catechin , Pharmacology , Cell Line, Tumor , Cell Survival , Herpesvirus 4, Human , JNK Mitogen-Activated Protein Kinases , Metabolism , MAP Kinase Kinase 4 , Mitogen-Activated Protein Kinase Kinases , Metabolism , Nasopharyngeal Neoplasms , Metabolism , Pathology , Virology , Phosphorylation , Protein Transport , Proto-Oncogene Proteins c-jun , Metabolism , Signal Transduction , Transcription Factor AP-1 , Metabolism , Viral Matrix Proteins , Genetics , Metabolism , PhysiologyABSTRACT
<p><b>OBJECTIVE</b>To elucidate the expression of tanscription factor Ets-1 mediated by EB virus encoded latent membrane protein 1 (LMP1) in nasopharyngeal carcinoma (NPC) cells.</p><p><b>METHODS</b>LMP1-expressing NPC HNE2 cells regulated by Tet-on system (pTet-on-LMP1 HNE2) were used. Expression of LMP1 and Ets-1 was observed after induction with Doxycycline (Dox). Expression of Ets-1 mRNA and protein was detected by RT-PCR and Western blot, respectively. The phosphorylation level of Ets-1 protein was examined by co-immunoprecipitation. The DNA binding activity of Ets-1 was detected by electrophoretic-mobility shift assay (EMSA).</p><p><b>RESULTS</b>After induction with Dox in pTet-on-LMP1 HNE2 cells, to some extent, the expression of Ets-1 mRNA and protein, its phosphorylation level and DNA binding activity were increased with enhancement of LMP1 expression.</p><p><b>CONCLUSION</b>LMP1 induces transcriptional activation and expression of Ets-1 which may contribute to the development of NPC.</p>
Subject(s)
Humans , Carcinoma, Squamous Cell , Metabolism , Pathology , Virology , Cell Line, Tumor , Doxycycline , Pharmacology , Herpesvirus 4, Human , Nasopharyngeal Neoplasms , Metabolism , Pathology , Virology , Phosphorylation , Proto-Oncogene Protein c-ets-1 , Proto-Oncogene Proteins , Genetics , Proto-Oncogene Proteins c-ets , RNA, Messenger , Genetics , Transcription Factors , Genetics , Viral Matrix Proteins , Genetics , PhysiologyABSTRACT
Phosphate-dissolving microorganisms are widely distributed in soil, rhizosphere and other ecological environment. Understanding the characteristics of these microorganisms in solubilizing phosphates is helpful to apply them in improving P use efficiency. The obtained results indicated that the fungi had much higher capacity to dissolve the rock than the bacteria. Existence of Fe, Al, Mg and Na in the culture media reduced the rock solubilization by the bacteria, but increased the solubilization of the fungi. The higher content of the rock in the media, the lower capacity of the rock phosphate solubilization was found. The capacity was also significantly reduced if the concentration of C material in the media was higher than 3%. It was also found that the microorganisms destroyed the rock structure. The P was more easily released from the rock at further incubation. In conclusion, there is some potential to utilize the microorganisms to activate the rock phosphate.