Objective To investigate the expression and prognostic significance of mediator complex subunit 8 (MED8) in gastric cancer and its impact on the cell cycle.Methods The expression of MED8 in gastric cancer and adjacent tissues and its correlation with patients' prognosis were analyzed using public databases.A validation cohort of 104 patients who underwent radical resection for gastric cancer in the First Affiliated Hospital of Bengbu Medical College from June 2012 to July 2017 was included.The receiver operating characteristic curve was established to evaluate the predictive value of MED8 for postoperative 5-year survival.Bioinformatics tools were used to predict the biological roles of MED8 in gastric cancer.The effect of the MED8 level on the G1/S phase transition of gastric cancer cells (MGC-803) was analyzed via lentivirus transduction and flow cytometry.Western blotting was carried out to assess the impact of MED8 expression on the protein levels of cyclin-dependent kinase 4(Cdk4) and G1/S-specific cyclin-D1(CyclinD1) in MGC-803 cells.Results The high expression of MED8 in the gastric cancer tissue was associated with poor prognosis (P<0.001) and had prognostic significance (area under curve=0.733,P<0.001).Gene enrichment analysis suggested that MED8 may participate in the cell cycle process.Flow cytometry results revealed that the upregulation of MED8 expression promoted the transition of MGC-803 cells from the G1 phase to the S phase (P<0.001),while the downregulation of MED8 had the opposite effect (P<0.001).Western blotting showed increases in the protein levels of Cdk4 and CyclinD1 in MGC-803 cells with upregulated MED8 expression (all P<0.001),and decreases in the cells with downregulated MED8 expression (all P<0.001).Conclusion MED8 is highly expressed in gastric cancer and may affect its progression and prognosis by regulating the G1/S phase transition of gastric cancer cells.
Humans ; Stomach Neoplasms ; Prognosis ; Cell Proliferation ; Cell Cycle ; Mediator Complex/metabolism* ; Cell Line, Tumor

PURPOSE: The peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor that regulates expression of mediators of lipid metabolism and the inflammatory response. Thyroid hormone receptor-associated proteins 220 (TRAP220) is an essential component of the TRAP/Mediator complex. The objective of this study was to clarify whether PPARgamma or TRAP220 are significant prognostic markers in resectable colorectal cancer (CRC). MATERIALS AND METHODS: A total of 399 patients who underwent curative resection for CRC were enrolled. We investigated the presence of PPARgamma and TARP220 in CRC tissues and adjacent normal tissues by immunohistochemistry. Correlation between the expression of these factors and clinicopathologic features and survival was investigated. RESULTS: Median age of the patients was 63 years (range, 22 to 87 years), and median follow-up duration 61.1 months (range, 2 to 114 months). PPARgamma and TRAP220 expression showed significant correlation with depth of invasion (p=0.013 and p=0.001, respectively). Expression of TRAP220 also showed association with lymph node metastasis and TNM stage (p=0.001). Compared with patients with TRAP220 negative tumors, patients with TRAP220 positive tumors had longer 5-year disease-free survival (DFS) tendency (p=0.051). Patients who were PPARgamma positive combined with TRAP220 positive had a better 5-year DFS (64.8% vs. 79.3%, p=0.013). In multivariate analysis expression of both PPARgamma and TRAP220 significantly affected DFS (hazard ratio, 0.620; 95% confidence interval, 0.379 to 0.997; p=0.048). CONCLUSION: TRAP220 may be a valuable marker for nodal metastasis and TNM stage. Tumor co-expression of PPARgamma and TRAP220 represents a biomarker for good prognosis in CRC patients.
Colorectal Neoplasms* ; Disease-Free Survival ; Follow-Up Studies ; Humans ; Immunohistochemistry ; Lipid Metabolism ; Lymph Nodes ; Mediator Complex Subunit 1* ; Multivariate Analysis ; Neoplasm Metastasis ; Peroxisomes* ; PPAR gamma* ; Prognosis ; Thyroid Gland

OBJECTIVE: To construct the eukaryotic expression vector of MJD1 with normal copies of CAG trinucleotide repetition and MJD1 with CAG trinucleotide repetition expansion mutation respectively, and to determine whether the polyglutamine expansion in ataxin-3 could lead to the formation of intranuclear aggregation. METHODS: The coding sequence of wild-type MJD1 and mutant MJD1 was amplified by PCR from pAS2-1-MJD20Q and pAS2-1-MJD68Q respectively. After being digested with BamH I and Hind III, the PCR products were inserted into pcDNA3. 1-Myc-His(-) B. The recombinant plasmids pcDNA3.1-Myc-His(-) B-MJD20Q and pcDNA3.1-Myc-His(-) B-MJD68Q were identified by enzyme digestion analysis and DNA sequencing. The recombinant plasmid was transfected into SH-SYSY cells and the expression of MJD1 in the transfected cells was analyzed by Western blot. The immunofluorescence of the transfected cells was examined using a confocal microscope to observe the formation of intranuclear aggregation. RESULTS: Enzyme digestion analysis and DNA sequencing showed that the target gene was cloned into pcDNA3. 1-Myc-His(-) B. The expression of MJD1 in the transfected cells was confirmed by Western blot; The SH-SY5Y cells transfected with pcDNA3. 1-Myc-His(-) B-MJD68Q showed the formation of intranuclear aggregation, but the cells transfected with pcDNA3.1-Myc-His(-) B-MJD20Q did not show such phenomenon. CONCLUSION The eukaryotic expression vectors of MJD1 has been successfully constructed; The polyglutamine expansion in ataxin-3 could lead to the formation of intranuclear aggregation.
Ataxin-1 ; Ataxin-3 ; Ataxins ; Base Sequence ; Eukaryotic Cells ; metabolism ; Genetic Vectors ; Humans ; Mediator Complex ; Molecular Sequence Data ; Nerve Tissue Proteins ; biosynthesis ; genetics ; Neuroblastoma ; metabolism ; pathology ; Nuclear Proteins ; biosynthesis ; genetics ; Plasmids ; genetics ; Receptors, Thyroid Hormone ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Repressor Proteins ; biosynthesis ; genetics ; Transfection ; Tumor Cells, Cultured

The Mediator Complex plays key roles in activating gene transcription in eukaryotes. Mediator of RNA polymerase II transcription subunit 12 homolog (MED12) is a subunit of the Mediator Complex and regulates the activity of the complex. MED12 is involved in a variety of cellular activities, and mutations in MED12 gene impair MED12 activities and are associated with several diseases, including Opitz-Kaveggia syndrome, Lujan syndrome, uterine leiomyomas and prostate cancer. This review will discuss the biological function of MED12 and the relationship between MED12 mutations and diseases.
Agenesis of Corpus Callosum ; genetics ; Anus, Imperforate ; genetics ; Constipation ; genetics ; Craniofacial Abnormalities ; genetics ; Female ; Genetic Predisposition to Disease ; Humans ; Leiomyoma ; genetics ; Male ; Marfan Syndrome ; genetics ; Mediator Complex ; genetics ; metabolism ; Mental Retardation, X-Linked ; genetics ; Muscle Hypotonia ; congenital ; genetics ; Mutation ; Prostatic Neoplasms ; genetics ; Transcription, Genetic ; Uterine Neoplasms ; genetics