Sp1 is a ubiquitous nuclear factor that plays a key role in maintaining basal transcription of 'house-keeping' genes. It has been demonstrated that Sp1 is involved in many cellular process, e.g.cell growth and differentiation. Sp1 plays an extremely important role in growth and metastasis of many tumors by regulating oncogenes, tumor suppressor genes, cell cycle control molecules, growth-related signal transductions, angiogenesis-related factors, as well as apoptosis. The expression of Sp1 and its activity are strictly regulated. Mechanisms include the modulation of Sp1 and interactions between Sp1 and other molecules. New treatment with Sp1 as the target will bring profound impacts on the strategy of clinical chemotherapy of tumor.
Apoptosis ; genetics ; Humans ; Neoplasm Metastasis ; genetics ; Neoplasms ; genetics ; Sp1 Transcription Factor ; genetics ; metabolism

We studied the function and mechanism of miR-24 in regulating beta-like globin gene expression. We first detected the expression of miR-24 during erythroid differentiation and also detected the globin gene expression in miR-24 overexpressing K562 cells through q-PCR. Dual-luciferase reporter assay and Western blotting were used to identify target genes of miR-24. "Rescue experiment" was further used to investigate the regulation of miR-24 on globin gene expression whether depending on targeting Sp1 or not. We found that miR-24 increased during hemin-induced K562 cells and EPO-induced HPCs (hematopoietic progenitor cells) erythroid differentiation. Overexpression of miR-24 in K562 cells promoted the epsilon- and gamma-globin gene expression during hemin-induced erythroid differentiation through targeting the negative globin regulator Sp1. These results suggested that miR-24 can improve the expression of beta-like globin gene through targeting Sp1.
Cell Differentiation ; Gene Expression Regulation ; Hematopoietic Stem Cells ; metabolism ; Humans ; K562 Cells ; MicroRNAs ; genetics ; Sp1 Transcription Factor ; genetics ; epsilon-Globins ; genetics ; gamma-Globins ; genetics

OBJECTIVE: To study the transcriptional regulation of SP1 on the scaffold protein ARRB1 and its influence on the progression of T-cell acute lymphoblastic leukemia (T-ALL). METHODS: pGL3-ARRB1-luc, pCDNA3.1-SP1 and other transcription factor plasmids that might be combined were constructed, and the binding of transcription factors to the promoter of ARRB1 was identified by dual luciferase reporter gene assay. Stable cell lines with over-expressed SP1 (JK-SP1) was constructed by lentiviral transfection, and the expression correlation of SP1 with ARRB1 was demonstrated by RT-PCR and Western blot. Further, the apoptosis, cell cycle and reactive oxygen species (ROS) were detected by flow cytometry. The effect of SP1 on propagation of leukemic cells was observed on NCG leukemic mice. RESULTS: The expression of fluorescein were enhanced by co-transfection with pCDNA3.1-SP1 and pGL3-ARRB1-luc plasmids in HEK293T cell line (P<0.001), meanwhile, compared with the control group, the expression of ARRB1 mRNA and protein were increased in JK-SP1 cells (both P<0.01). Further in vitro experiments showed that, compared with the control group, the apoptosis rate was higher (x=22.78%) , the cell cycle was mostly blocked in G₁ phase (63.00%), and the content of reactive oxygen species increased in JK-SP1 cells. And in vivo experiments showed that the mice injected with JK-SP1 cells through tail vein had a favorable overall survival time (average 33.8 days), less infiltration in liver and spleen tissue. CONCLUSION Transcription factor SP1 promotes the transcription and expression of ARRB1 by binding the the promoter of ARRB1 directly, thus delays the progress of T-ALL in vitro and in vivo. The study improves the pathogenesis of ARRB1 regulating the initiation and development of T-ALL, and provides theoretical basis for the development of new possible targeted drugs.
Humans ; Animals ; Mice ; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/genetics* ; HEK293 Cells ; Reactive Oxygen Species ; Transcription Factors ; T-Lymphocytes ; Cell Line, Tumor ; Sp1 Transcription Factor/metabolism*

OBJECTIVETo explore the feasibility of transfecting recombinant Sp1 into hypertrophic scar fibroblasts and investigate the proliferation and collagen I, III synthesis in the transfected cells.

METHODSRecombinant human Sp1 was transfected into hypertrophic scar fibroblasts with the karyocyte expressive vector. The expression of Sp1, collagen I, III mRNA was tested by real time PCR. The change of cell proliferation was observed with CCK8 colorimeter.

RESULTSAbout 30% of transfected hypertrophic scar fibroblasts showed green fluorescence positive. The relative expression of Sp1 mRNA in transfected cells, empty-vector cell or untransfected cells group was 5.26 +/- 0.76, 1.08 +/- 0.18, 1.09 +/- 0.15, respectively, showing a significant difference between thansfected and untransfected cells or between the transfected cells and empty-vector group (P <0.01, n = 5). Expression of collagen I, III mRNA was 2.49 +/- 0.40 and 1.88 +/- 0.30 in transfected cells, 0.96 +/- 0.18 and 0.95 +/- 0.18 in empty-vector cell, and 0.97 +/- 0.15 and 0.93 +/- 0.13 in untransfected cells, respectively, showing a significant difference between thansfected and untransfected cells or between the transfected cells and empty-vector group (P < 0.01, n = 5).

CONCLUSIONSThe hypertrophic scar fibroblasts could be as the target cells of Sp1 gene transfection. Sp1 gene may play an important role in abnormal collagen metabolism in hypertrophic scar.

Cell Proliferation ; Cells, Cultured ; Cicatrix, Hypertrophic ; genetics ; metabolism ; pathology ; Collagen ; metabolism ; Escherichia coli ; genetics ; Fibroblasts ; metabolism ; pathology ; Humans ; RNA, Messenger ; genetics ; Recombinant Proteins ; genetics ; Skin ; metabolism ; Sp1 Transcription Factor ; genetics ; Transfection

OBJECTIVETo determine the expression patterns of metastasis associated 1 family member 2 (MTA2) in gastric cancer and non-cancerous gastric mucosa, and analyze its relationship with nuclear transcription factor Sp1 expression.

METHODSTissue samples and clinicopathological information from 83 gastric cancer patients, who underwent surgery, were collected from Shanghai Rui Jin Hospital. All samples included cancer tissue and non-cancerous mucosa which was 5 cm away from the tumor lesion. The expression of MTA2 and Sp1 were detected by immunohistochemistry (IHC) staining. The mRNA of MTA2 was also detected by reverse transcription-polymerase chain reaction (RT-PCR). SPSS software was used for statistical analysis.

RESULTSThe expression of MTA2 protein was significantly higher in primary lesions of the gastric cancer than that in non-cancerous mucosa by IHC (31.3% vs 12.0%, P < 0.01). MTA2 expression was closely related with tumor invasion or T staging (χ(2) = 5.677, P < 0.05). Yet, no significant relationship was observed between MTA2 expression and other clinicopathological parameters, including the age, sex, tumor differentiation, Lauren classification, lymph node metastasis, distant metastasis, as well as pathological staging. Furthermore, MTA2 expression was concomitant with Sp1 expression (r = 0.320, P < 0.05). Elevated MTA2 expression was observed in Sp1 positive cancer tissues (χ(2) = 9.565, P < 0.01). RT-PCR results also demonstrated that MTA2 mRNA was also highly expressed in the tissue samples with Sp1 expression.

CONCLUSIONSMTA2 is highly expressed in the primary lesions of gastric cancer than that in adjacent non-cancerous tissues, and is closely related with tumor invasion. MTA2 expression is elevated in Sp1 positive gastric cancer.

Female ; Gene Expression Regulation, Neoplastic ; Histone Deacetylases ; genetics ; metabolism ; Humans ; Male ; Middle Aged ; Neoplasm Invasiveness ; Neoplasm Staging ; RNA, Messenger ; metabolism ; Repressor Proteins ; genetics ; metabolism ; Sp1 Transcription Factor ; metabolism ; Stomach Neoplasms ; metabolism ; pathology

We previously reported that trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, induced DLC-1 mRNA expression and accumulated acetylated histones H3 and H4 associated with the DLC-1 promoter in DLC-1 non-expressing gastric cancer cells. In this study, we demonstrated the molecular mechanisms by which TSA induced the DLC-1 gene expression. Treatment of the gastric cancer cells with TSA activates the DLC-1 promoter activity through Sp1 sites located at -219 and -174 relative to the transcription start site. Electrophoretic mobility-shift assay (EMSA) revealed that Sp1 and Sp3 specifically interact with these Sp1 sites and showed that TSA did not change their binding activities. The ectopic expression of Sp1, but not Sp3, enhances the DLC-1 promoter responsiveness by TSA. Furthermore, the TSA-induced DLC-1 promoter activity was increased by p300 expression and reduced by knockdown of p300. These results demonstrated the requirement of specific Sp1 sites and dependence of Sp1 and p300 for TSA-mediated activation of DLC-1 promoter.
Cell Line, Tumor ; Electrophoretic Mobility Shift Assay ; Histone Deacetylases/*antagonists & inhibitors/metabolism ; Humans ; Hydroxamic Acids/*pharmacology ; Promoter Regions, Genetic ; Sp1 Transcription Factor/genetics/*metabolism ; Sp3 Transcription Factor/genetics/metabolism ; Stomach Neoplasms/*metabolism ; Transcription, Genetic ; Tumor Suppressor Proteins/*biosynthesis/genetics ; p300-CBP Transcription Factors/genetics/metabolism

PURPOSE: To evaluate the possible influence of G-->T substitution at the Sp1-binding site of the COLIA1 gene on the risk of pelvic organ prolapse (POP). MATERIALS AND METHODS: The study group consisted of 15 women with advanced stage POP. Fifteen control subjects with uterine myomas among the postmenopausal women were matched for age and parity. DNA was obtained from peripheral blood leukocytes. The fragments of the first intron of the COLIA1 gene were amplified by real time polymerase chain reaction. The polymorphism was identified using LightCycler Technology with hybridization probes. Sequencing reactions were performed on each template using commercial primer. RESULTS: Two groups had no significant difference in medical history, surgical, and smoking history. The homozygous peaks in two groups were noted at 57degrees C on melting curve analysis. Sequencing reactions confirmed the G/G alleles in the 30 specimens tested. We could not find any polymorphism at the Sp1-binding site in COLIA1 gene with advanced stage POP. Statistical significance was considered to be p < .05. CONCLUSION: The polymorphism of the Sp1-binding site in the COLIA1 gene did not contribute to the development of POP in Korea.
Aged ; Asian Continental Ancestry Group/genetics ; Binding Sites/genetics ; Collagen Type I/*genetics ; Female ; Genetic Predisposition to Disease ; Humans ; Middle Aged ; Pelvic Organ Prolapse/*genetics ; Polymerase Chain Reaction ; Polymorphism, Genetic/*genetics ; Sp1 Transcription Factor/*metabolism

OBJECTIVETo investigate the expression of transcription factor Sp1 in human gastric cancer tissues and normal gastric mucosa, and its prognostic significance.

METHODSBy using immunohistochemistry, we studied the Sp1 expression patterns in 65 cases of gastric cancer with various clinico-pathologic characteristics, and 40 normal gastric mucosa specimens obtained from patients who underwent partial gastrectomy for benign gastric diseases. The significance of Sp1 expression on the survival of patients was evaluated.

RESULTSThe expression rate of Sp1 in normal gastric mucosa was 12.5% (5/40). The positively stained glandular cells were mainly limited to those in the neck region. Cells at the basal portion of the gland were essentially negative. In sharp contrast, Sp1 expression rate in gastric cancer lesions was 53.8% (35/65). The medium survival time in patients who had a tumor with negative, weak and strong Sp1 expression was 1700, 1560 and 1026 days, respectively (P = 0.036). Sp1 protein expression was closely related to the depth of tumor invasion and TNM stage (P = 0.001, P = 0.026), but not related to the number of metastatic lymph nodes and Lauren's classification (P = 0.306, P = 0.667).

CONCLUSIONNormal and malignant gastric tissues have unique Sp1 expression patterns. Sp1 might be served as an independent prognostic factor.

Adenocarcinoma ; metabolism ; pathology ; Aged ; Biomarkers, Tumor ; biosynthesis ; genetics ; Female ; Follow-Up Studies ; Gastric Mucosa ; metabolism ; Humans ; Male ; Middle Aged ; Neoplasm Invasiveness ; Prognosis ; Sp1 Transcription Factor ; biosynthesis ; genetics ; Stomach Neoplasms ; metabolism ; pathology

OBJECTIVETo investigate the regulatory mechanism of the transcription of tumor metastasis suppressor gene TMSG-1.

METHODSLuciferase reporter assay and site-directed mutagenesis were used to analyze the regulatory region of TMSG-1. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) were carried out to verify the interaction of KLF6 and Sp1 with the regulatory region of TMSG-1. Co-immunoprecipitation (CoIP) was performed to analyze the interaction between KLF6 and Sp1. TMSG-1 and wt-KLF6 mRNA expressions in cells with different metastatic capacities were quantitated by real-time PCR. Cell invasive capability was determined by Matrigel invasion assay.

RESULTSA 63 bp inducible regulatory region (+59 bp - +123 bp) in exon 1 was identified by luciferase assay using reporter plasmids with a series of TMSG-1 regulatory region deletions. Mutations in KLF6/Sp1 binding sites of this region resulted in a decrease of luciferase activity, while cotransfection with KLF6 or Sp1 expressing plasmids led to a remarkable increase of luciferase activity. EMSA and ChIP demonstrated that KLF6 as well as Sp1 interacted with this region. CoIP also indicated a possible interaction between KLF6 and Sp1 proteins. In the highly metastatic cell sublines, a low level of wild type KLF6 was associated synchronously with a low TMSG-1 level. Prostate carcinoma cells overexpressing KLF6 exhibited a higher TMSG-1 level and a lower invasive capability.

CONCLUSIONSTranscription factor complex of KLF6 and Sp1 may participate in the inducible transcriptional regulation of TMSG-1, and a decreased wild type KLF6 expression is likely associated with a low TMSG-1 level in the highly metastatic cell sublines.

Binding Sites ; genetics ; Cell Line, Tumor ; Electrophoretic Mobility Shift Assay ; Humans ; Immunoprecipitation ; Kruppel-Like Factor 6 ; Kruppel-Like Transcription Factors ; genetics ; metabolism ; Lung Neoplasms ; metabolism ; pathology ; Male ; Membrane Proteins ; genetics ; metabolism ; Mutagenesis, Site-Directed ; Mutation ; Neoplasm Invasiveness ; Prostatic Neoplasms ; metabolism ; pathology ; Proto-Oncogene Proteins ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Sp1 Transcription Factor ; genetics ; metabolism ; Sphingosine N-Acyltransferase ; genetics ; metabolism ; Transcriptional Activation ; Transfection ; Tumor Suppressor Proteins ; genetics ; metabolism

The process of aging is mitigated by the maintenance and repair of chromosome ends (telomeres), resulting in extended lifespan. This review examines the molecular mechanisms underlying the actions and regulation of the enzyme telomerase reverse transcriptase (TERT), which functions as the primary mechanism of telomere maintenance and regulates cellular life expectancy. Underpinning increased cell proliferation, telomerase is also a key factor in facilitating cancer cell immortalization. The review focuses on aspects of hormonal regulations of telomerase, and the intracellular pathways that converge to regulate telomerase activity with an emphasis on molecular interactions at protein and gene levels. In addition, the basic structure and function of two key telomerase enzyme components-the catalytic subunit TERT and the template RNA (TERC) are discussed briefly.
Aging ; genetics ; metabolism ; Alternative Splicing ; Animals ; Base Sequence ; DNA Methylation ; Enzyme Activation ; Epigenesis, Genetic ; Gene Expression Regulation, Enzymologic ; Humans ; Mice ; Mutation ; Neoplasms ; enzymology ; genetics ; Promoter Regions, Genetic ; Protein Folding ; RNA ; genetics ; metabolism ; Signal Transduction ; Sp1 Transcription Factor ; genetics ; metabolism ; Telomerase ; genetics ; metabolism ; Telomere ; genetics ; metabolism