BACKGROUND: Although esculetin, a coumarin compound, is known to induce apoptosis in human cancer cells, the effects and molecular mechanisms on the apoptosis in human malignant melanoma (HMM) cells are not well understood yet. In this study, we investigated the anti-proliferative effects of esculetin on the G361 HMM cells. METHODS: We analyzed the anti-proliferative effects and molecular mechanisms of esculetin on G361 cells by a 3-(4,5-dimethylthiazol- 2-yl)-5-(3-carboxymethoxy phenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay, 4\',6-diamidino-2-phenylindole staining and Western blotting. RESULTS: Esculetin exhibited significant anti-proliferative effects on the HMM cells in a dose-dependent manner. Interestingly, we found that esculetin induced nuclear shrinkage and fragmentation, typical apoptosis markers, by suppression of Sp1 transcription factor (Sp1). Notably, esculetin modulated Sp1 downstream target genes including p27, p21 and cyclin D1, resulted in activation of apoptosis signaling molecules such as caspase-3 and PARP in G361 HMM cells. CONCLUSIONS: Our results clearly demonstrated that esculetin induced apoptosis in the HMM cells by downregulating Sp1 protein levels. Thus, we suggest that esculetin may be a potential anti-proliferative agent that induces apoptotic cell death in G361 HMM cells.
Apoptosis ; Blotting, Western ; Caspase 3 ; Cell Death ; Cyclin D1 ; Humans* ; Melanoma* ; Sp1 Transcription Factor

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

OBJECTIVETo study the oncogene transcriptor c-myc, stimulatory protein 1 (SP1) expression in ameloblastoma (AB) and their relation with telomerase reverse transcripase (hTERT), and to investigate the clinical biological characteristics of AB.

METHODSThe expression was observed in AB by in situ hybridization and SP method.

RESULTSThe positive rates of c-myc mRNA, hTERT mRNA and SP1 protein were 81.5% (44/54), 94.4% (51/54) and 83.3% (45/54), respectively. Their positive rates increased as AB recurred and transformed malignantly. A strong correlation was found between hTERT and c-myc, hTERT and SP1 (rs = 0.853, P < 0.001; rs = 0.900, P < 0.001).

CONCLUSIONActivity of telomerase plays an important role in the tumorigenesis development of AB. Increasing of hTERT expression may be related to c-myc and SP1. The expression of these three parameters has a significant correlation with the clinical biological characteristics of AB.

Ameloblastoma ; metabolism ; Humans ; Proto-Oncogene Proteins c-myc ; metabolism ; Sp1 Transcription Factor ; metabolism ; Telomerase ; metabolism

The aim of this study was to screen the active regions and transcription factor binding sites in the promoter of the CBD103 gene related to Arctic fox coat color, and to provide a basis for revealing the molecular genetic mechanism of CBD103 gene regulating the coat color formation. The 5'-flanking region fragment 2 123 bp of Arctic fox CBD103 gene was cloned, and 4 truncated promoter reporter vectors of different lengths were constructed. The promoter activity was detected by the dual-luciferase reporter assay system. Point mutations were performed on the 3 predicted specificity protein 1 (Sp1) transcription factor binding sites in the highest promoter active region, and 3 mutant vectors were constructed. The activity was then detected by the dual-luciferase reporter assay system. The results showed that the region 1 656 (-1 604/+51) had the highest activity in the 4 truncated promoters of different lengths, and the promoter activity of the three mutant vectors constructed in this region were significantly lower than that of the wild type (fragment 1 656). The region of -1 604 /+51 was the core promoter region of CBD103 gene in Arctic fox and -1 552/-1 564, -1 439/-1 454 and -329/-339 regions were positive regulatory regions. This study successfully obtained the core promoter region and positive regulation regions of the Arctic fox CBD103 gene, which laid a foundation for further study on the molecular genetic mechanism of this gene regulating Arctic fox coat color.
Animals ; Binding Sites ; Foxes ; Luciferases ; Promoter Regions, Genetic ; Sp1 Transcription Factor ; beta-Defensins

OBJECTIVE: In this study, the role and potential mechanism of transformer 2β (Tra2β) in cervical cancer were explored. METHODS: The transcriptional data of Tra2β in patients with cervical cancer from Gene Expression Profiling Interactive Analysis (GEPIA) and cBioPortal databases were investigated. The functions of Tra2β were evaluated by using Western blot, MTT, colony formation, Transwell assays, and nude mouse tumor formation experiments. Target genes regulated by Tra2β were studied by RNA-seq. Subsequently, representative genes were selected for RT-qPCR, confocal immunofluorescence, Western blot, and rescue experiments to verify their regulatory relationship. RESULTS: The dysregulation of Tra2β in cervical cancer samples was observed. Tra2β overexpression in Siha and Hela cells enhanced cell viability and proliferation, whereas Tra2β knockdown showed the opposite effect. Alteration of Tra2β expression did not affect cell migration and invasion. Furthermore, tumor xenograft models verified that Tra2β promoted cervical cancer growth. Mechanically, Tra2β positively regulated the mRNA and protein level of SP1, which was critical for the proliferative capability of Tra2β. CONCLUSION This study demonstrated the important role of the Tra2β/SP1 axis in the progression of cervical cancer in vitro and in vivo, which provides a comprehensive understanding of the pathogenesis of cervical cancer.
Humans ; Animals ; Mice ; Female ; Uterine Cervical Neoplasms/genetics* ; HeLa Cells ; Cell Proliferation ; Biological Assay ; Transcription Factors ; Sp1 Transcription Factor/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 investigate the expression of transcription factor SP1, vascular endothelial growth factor(VEGF) and CD34 in serosa-infiltrating gastric cancer and their relationship with biological behavior and survival rate.

METHODSImmunohistochemical technique was used to detect the expression of SP1, VEGF and CD34(described by microvessel density, MVD) in 68 specimens with serosa-infiltrating gastric cancer.

RESULTSThe positive expression rates of SP1 and VEGF in serosa-infiltrating gastric cancer were 50.0% and 52.9% respectively. In positive SP1 specimens, the positive rate of VEGF(73.5%) was significantly higher than that of negative SP1 specimens (32.4%, chi(2)=11.57, P=0.01). The mean tumor MVD was correlated with the expression levels of SP1 and VEGF(P<0.01). There was a significant correlation of the SP1 expression with tumor size and growth pattern(P =0.01). The expression levels of VEGF and MVD were correlated with Borrmann types, cell differentiation, metastatic lymph nodes and growth pattern(P<0.01). Univariate analysis revealed that SP1 and VEGF expression, MVD, Borrmann types, lymph node metastasis, tumor size and growth pattern were significant prognostic factors related to survival time. Multivariate analysis showed that SP1 expression, MVD and growth pattern were independently prognostic factors of poor survival.

CONCLUSIONSThe activation of SP1 contributes to angiogenesis and metastasis in gastric cancer through the up-regulation of VEGF. SP1, VEGF and MVD may serve as valuable indicators of biological behavior of gastric cancer. SP1 protein expression is not related with the number of metastatic lymph nodes. SP1 expression and MVD may serve as valuable indicators of prognosis in gastric carcinoma.

Adult ; Aged ; Antigens, CD34 ; metabolism ; Female ; Humans ; Male ; Microcirculation ; Middle Aged ; Prognosis ; Sp1 Transcription Factor ; metabolism ; Stomach Neoplasms ; blood supply ; metabolism ; pathology ; Vascular Endothelial Growth Factor A ; metabolism

Nicotinamide at millimolar concentrations affects cell survival in various conditions, and is being utilized therapeutically in many human diseases. However, the effect of an acute treatment of nicotinamide at such high dose on gene expression and cellular metabolism has rarely been determined previously. In this study, we found that levels of O-N-acetylglucosamin(O- GlcNAc)ylated proteins including Sp1 acutely decreased upon treatment of 10 mM nicotinamide. Concomitantly, Sp1 protein level decreased rapidly through accelerated proteasome-mediated proteolysis. Cotreatment of glucosamine or 2-deoxyglucose, which inhibits protein deGlcNAcylation, effectively blocked the decrease induced by nicotinamide. Interestingly, the decline in the levels of Sp1 and protein O- GlcNAcylation was only transient lasting for two days post treatment, and this pattern matched closely the rapid fluctuation of the cellular [NAD(+)]. Our results suggest a possible link between cellular nicotinamide metabolism and protein O-GlcNAcylation, and an existence of cellular [NAD(+)] homeostasis.
Acetylglucosamine/*metabolism ; Blotting, Western ; Dose-Response Relationship, Drug ; Down-Regulation/*drug effects ; Humans ; Hydrolysis ; Niacinamide/*pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Sp1 Transcription Factor/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

OBJECTIVETo observe the expression of hepatocyte growth factor (HGF), transcription factor SP1, vascular endothelial growth factor (VEGF) and CD34 (demonstrating by microvessel density, MVD) in serosa-infiltrative gastric cancer (T3) and their relations with the pathobiological behavior of the tumor, and to investigate the molecular basis of the defluxion of gastric cancer cells in abdominal cavity and its influence on prognosis.

METHODSSelective collection of peritoneal lavage was obtained from 80 patients with serosa-infiltrative gastric cancer received operation from April to December in 2007. The cancer cells were detected by using peritoneal lavage cytology (PLC) and immunochemistry of cytokeratin 18 (CK18). Immunohistochemistry was applied to detect the HGF, SP1, VEGF and CD34 in serosa-infiltrative gastric cancer tissues. The rigorous follow-up was carried out for the patients.

RESULTSThe positive rate of PLC was 63.8% (51/80), and the positive rate of immunochemistry of CK18 was 75.0% (60/80). The positive cases in PLC were positive in immunochemistry of CK18 also, while 9 negative cases in PLC were positive with CK18, and of them 6 cases were determined positive with exfoliated cancer cells through pathological consulting. So the positive rate of exfoliated cells of this group was 71.3% (57/80). The positive rates of HGF, SP1 and VEGF in gastric cancer tissues were 57.5%, 52.5% and 55.0%, respectively, and were all significantly correlated with the MVD (P < 0.05). HGF, SP1, VEGF and MVD were correlated with the positive rate of exfoliated cells (P < 0.05). HGF, SP1, VEGF and MVD were found significantly related to prognosis on univariate analysis (P < 0.05), and it was demonstrated that HGF, SP1 and VEGF were independent prognostic influential factors on Logistic regression analysis (P < 0.05).

CONCLUSIONSThe expression of HGF, SP1, VEGF and MVD are related with the biological behaviour of serosa-infiltrative gastric cancer. The detection of these factors might be helpful in predicting the defluxion of gastric cancer cells and postoperative recurrence.

Antigens, CD34 ; metabolism ; Female ; Follow-Up Studies ; Hepatocyte Growth Factor ; metabolism ; Humans ; Male ; Neoplasm Invasiveness ; Neovascularization, Pathologic ; Peritoneal Lavage ; Prognosis ; Serous Membrane ; pathology ; Sp1 Transcription Factor ; metabolism ; Stomach Neoplasms ; metabolism ; pathology ; Vascular Endothelial Growth Factor A ; metabolism