scholarly journals Human gastrin-releasing peptide receptor gene regulation requires transcription factor binding at two distinct CRE sites

2008 ◽  
Vol 295 (1) ◽  
pp. G153-G162 ◽  
Author(s):  
Dharmaraj Chinnappan ◽  
Xiangping Qu ◽  
Dongmei Xiao ◽  
Anita Ratnasari ◽  
H. Christian Weber
Keyword(s):  
Transcription Factor ◽  
Cancer Cells ◽  
Transcriptional Activation ◽  
Gastrointestinal Cancer ◽  
Molecular Mechanisms ◽  
Receptor Gene ◽  
Ectopic Expression ◽  
Migration And Invasion ◽  
Wild Type ◽  
Gastrin Releasing Peptide

Ectopic expression of the gastrin-releasing peptide (GRP) receptor (GRP-R) occurs frequently in human malignancies of the gastrointestinal tract. Owing to paracrine and autocrine interaction with its specific high-affinity ligand GRP, tumor cell proliferation, migration, and invasion might ensue. Here we provide the first insights regarding molecular mechanisms of GRP-R regulation in gastrointestinal cancer cells. We identified by EMSA and chromatin immunoprecipitation assays two cAMP response element (CRE) binding sites that recruited transcription factor CRE binding protein (CREB) to the human GRP-R promoter. Transfection studies with a wild-type human GRP-R promoter reporter and corresponding CRE mutants showed that both CRE sites are critical for basal transcriptional activation in gastrointestinal cancer cells. Forced expression of cAMP-dependent effectors CREB and PKA resulted in robust upregulation of human GRP-R transcriptional activity, and this overexpression strictly required intact wild-type CRE sites. Direct cAMP stimulation with forskolin resulted in enhanced human GRP-R promoter activity only in HuTu-80 cells, but not in Caco-2 cells, coinciding with forskolin-induced CREB phosphorylation occurring only in HuTu-80 but not Caco-2 cells. In summary, CREB is a critical regulator of human GRP-R expression in gastrointestinal cancer and might be activated through different upstream intracellular pathways.

scholarly journals The AP2/ERF Transcription Factor SlERF.F5 Functions in Leaf Senescence in Tomato

2021 ◽  
Author(s):  
Yanan Chen ◽  
Panpan Feng ◽  
Boyan Tang ◽  
Zongli Hu ◽  
Qiaoli Xie ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Jasmonic Acid ◽  
Leaf Senescence ◽  
Molecular Mechanisms ◽  
Receptor Gene ◽  
Signal Transduction Pathway ◽  
Ethylene Biosynthesis ◽  
Pcr Analysis ◽  
Ethylene Response Factor ◽  
Wild Type

Abstract The process of plant senescence is complex and highly coordinated, and is regulated by many endogenous and environmental signals. Ethylene and jasmonic acid are well-known senescence inducers, but their molecular mechanisms for inducing leaf senescence have not been fully elucidated. Here, we studied a receptor gene downstream of an ethylene signal transduction pathway, ETHYLENE RESPONSE FACTOR F5 (SlERF.F5). The silence of SlERF.F5 causes accelerated senescence induced by age, darkness, ethylene, and jasmonic acid. However, overexpression of SlERF.F5 may delay leaf senescence. We further found that silencing of SlERF.F5 inhibited the expression of chlorophyll-related genes CHLH, CHLM, POR, CAO1, GUN4, PPH, SGR1, RBCS, and AUREA genes, and the light-responsive RBCS and LHCA1 gene. Moreover, silencing of SlERF.F5 increases the sensitivity of SlERF.F5-RNAi lines to ethylene and jasmonic acid compared to wild type. In the dark-induced aging experiment, the qRT-PCR analysis showed the expression levels of genes related to the ethylene biosynthesis pathway and the jasmonic acid signaling pathway in SlERF.F5-RNAi lines increased compared with wild type. Yeast two-hybrid experiments showed that SlERF.F5 and SlMYC2 (a transcription factor downstream of the JA receptor) can interact physically, thereby mediating the role of SlERF.F5 in jasmonic acid-induced leaf senescence. Collectively, our research provides new insights into how ethylene and jasmonic acid promote leaf senescence in tomatoes.

scholarly journals B-box transcription factor 28 regulates flowering by interacting with constans

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yin Liu ◽  
Guang Lin ◽  
Chunmei Yin ◽  
Yuda Fang
Keyword(s):  
Transcription Factor ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Ectopic Expression ◽  
Shade Avoidance ◽  
Structural Domains ◽  
Abiotic And Biotic Stresses ◽  
Biotic Stresses ◽  
Group Members ◽  
Redundant Role

Abstract B-box transcription factors (BBXs) are important regulators of flowering, photomorphogenesis, shade-avoidance, abiotic and biotic stresses and plant hormonal pathways. In Arabidopsis, 32 BBX proteins have been identified and classified into five groups based on their structural domains. Little is known about the fifth group members (BBX26–BBX32) and the detailed molecular mechanisms relevant to their functions. Here we identified B-box transcription factor 28 (BBX28) that interacts with Constans (CO), a transcriptional activator of Flowering Locus T (FT). Overexpressing BBX28 leads to late flowering with dramatically decreased FT transcription, and bbx28 deficient mutant displays a weak early flowering phenotype under long days (LD), indicating that BBX28 plays a negative and redundant role in flowering under LD. Additionally, the interaction between BBX28 and CO decreases the recruitment of CO to FT locus without affecting the transcriptional activation activity of CO. Moreover, the N-terminal cysteines, especially those within the B-box domain, are indispensable for the heterodimerization between BBX28 and CO and activation of CO on FT transcription. Genetic evidences show that the later flowering caused by BBX28 overexpression is compromised by CO ectopic expression. Collectively, these results supported that BBX28 functions with CO and FT to negatively regulate Arabidopsis flowering, in which the N-terminal conserved cysteines of BBX28 might play a central role.

Long non-coding RNA LINC00982 up-regulates CTSF expression to inhibit gastric cancer progression via the transcription factor HEY1

2020 ◽  
Author(s):  
Lei Zheng ◽  
Junli Cao ◽  
Lijie Liu ◽  
Hongmei Xu ◽  
Lanlan Chen ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Transcription Factor ◽  
Cancer Cells ◽  
Molecular Mechanisms ◽  
Luciferase Assay ◽  
Migration And Invasion ◽  
Gastric Cancer Cells ◽  
Non Coding Rna ◽  
Cancer Tissues ◽  
Long Non Coding Rna

Upregulating the expression of long non-coding RNA LINC00982 controlled cell proliferation in gastric cancer, but the regulatory molecular mechanisms are yet to be expounded. We here aimed to elaborate how LINC00982 regulated the malignancy of gastric cancer cells. RT-qPCR and Western blot analysis were used to detect the expression of LINC00982 and CTSF in gastric cancer tissues and cells. Modulatory effect of LINC00982 on gastric cancer cells was assessed by CCK-8, colony formation, Transwell migration and invasion assays. The relationship between LINC00982, HEY1 and CTSF was examined by RIP, luciferase assay, and ChIP, and their interaction in the regulation of gastric cancer cellular functions was analyzed by performing gain-of-function and rescue assays. The nude mouse model of tumor formation was developed to examine the effects of LINC00982 on tumorigenesis. LINC00982 was lowly expressed in gastric cancer tissues, while its overexpression impaired the proliferative, migratory and invasive properties of gastric cancer cells. Furthermore, LINC00982 could bind to transcription factor HEY1 and inhibited its expression. Through blocking the binding of HEY1 to CTSF promoter. LINC00982 promoted the expression of CTSF. Overexpression of HEY1 or inhibition of CTSF could reverse the anti-tumor effects of LINC00982 on gastric cancer, which were further demonstrated in vivo. Taken together, LINC00982 acted as a tumor suppressor in gastric cancer, which is therefore suggested to be a potential anti-tumor target for gastric cancer.

scholarly journals TEAD4 modulated LncRNA MNX1-AS1 contributes to gastric cancer progression partly through suppressing BTG2 and activating BCL2

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
You Shuai ◽  
Zhonghua Ma ◽  
Weitao Liu ◽  
Tao Yu ◽  
Changsheng Yan ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cancer Progression ◽  
Molecular Mechanisms ◽  
Mechanistic Model ◽  
Ectopic Expression ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Tissue Samples ◽  
Reporter Assays

Abstract Background Gastric cancer (GC) is the third leading cause of cancer-related mortality globally. Long noncoding RNAs (lncRNAs) are dysregulated in obvious malignancies including GC and exploring the regulatory mechanisms underlying their expression is an attractive research area. However, these molecular mechanisms require further clarification, especially upstream mechanisms. Methods LncRNA MNX1-AS1 expression in GC tissue samples was investigated via microarray analysis and further determined in a cohort of GC tissues via quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. Cell proliferation and flow cytometry assays were performed to confirm the roles of MNX1-AS1 in GC proliferation, cell cycle regulation, and apoptosis. The influence of MNX1-AS1 on GC cell migration and invasion was explored with Transwell assays. A xenograft tumour model was established to verify the effects of MNX1-AS1 on in vivo tumourigenesis. The TEAD4-involved upstream regulatory mechanism of MNX1-AS1 was explored through ChIP and luciferase reporter assays. The mechanistic model of MNX1-AS1 in regulating gene expression was further detected by subcellular fractionation, FISH, RIP, ChIP and luciferase reporter assays. Results It was found that MNX1-AS1 displayed obvious upregulation in GC tissue samples and cell lines, and ectopic expression of MNX1-AS1 predicted poor clinical outcomes for patients with GC. Overexpressed MNX1-AS1 expression promoted proliferation, migration and invasion of GC cells markedly, whereas decreased MNX1-AS1 expression elicited the opposite effects. Consistent with the in vitro results, MNX1-AS1 depletion effectively inhibited the growth of xenograft tumour in vivo. Mechanistically, TEAD4 directly bound the promoter region of MNX1-AS1 and stimulated the transcription of MNX1-AS1. Furthermore, MNX1-AS1 can sponge miR-6785-5p to upregulate the expression of BCL2 in GC cells. Meanwhile, MNX1-AS1 suppressed the transcription of BTG2 by recruiting polycomb repressive complex 2 to BTG2 promoter regions. Conclusions Our findings demonstrate that MNX1-AS1 may be able to serve as a prognostic indicator in GC patients and that TEAD4-activatd MNX1-AS1 can promote GC progression through EZH2/BTG2 and miR-6785-5p/BCL2 axes, implicating it as a novel and potent target for the treatment of GC.

scholarly journals Transcriptional Activation in Yeast Cells Lacking Transcription Factor IIA

Genetics ◽  
1999 ◽  
Vol 153 (4) ◽  
pp. 1573-1581 ◽  
Author(s):  
Susanna Chou ◽  
Sukalyan Chatterjee ◽  
Mark Lee ◽  
Kevin Struhl
Keyword(s):  
Transcription Factor ◽  
Transcriptional Activation ◽  
Large Subunit ◽  
Yeast Cells ◽  
Specific Cell ◽  
Wild Type ◽  
Activation Domains ◽  
Cycle Arrest ◽  
General Transcription Factor

Abstract The general transcription factor IIA (TFIIA) forms a complex with TFIID at the TATA promoter element, and it inhibits the function of several negative regulators of the TATA-binding protein (TBP) subunit of TFIID. Biochemical experiments suggest that TFIIA is important in the response to transcriptional activators because activation domains can interact with TFIIA, increase recruitment of TFIID and TFIIA to the promoter, and promote isomerization of the TFIID-TFIIA-TATA complex. Here, we describe a double-shut-off approach to deplete yeast cells of Toa1, the large subunit of TFIIA, to <1% of the wild-type level. Interestingly, such TFIIA-depleted cells are essentially unaffected for activation by heat shock factor, Ace1, and Gal4-VP16. However, depletion of TFIIA causes a general two- to threefold decrease of transcription from most yeast promoters and a specific cell-cycle arrest at the G2-M boundary. These results indicate that transcriptional activation in vivo can occur in the absence of TFIIA.

scholarly journals CDX2 and Reg IV expression and correlation in gastric cancer

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dandan Chai ◽  
Huifen Du ◽  
Kesheng Li ◽  
Xueliang Zhang ◽  
Xiaoqin Li ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Migration ◽  
Cancer Cells ◽  
Real Time ◽  
Real Time Pcr ◽  
Ectopic Expression ◽  
Rank Correlation ◽  
Migration And Invasion ◽  
Gastric Cancer Cells ◽  
Cell Migration And Invasion

Abstract Background Ectopic expression of CDX2 is associated with the development and progression of gastric cancer. Previous studies showed that CDX2 may be an upstream regulator of Reg IV expression in gastric cancer, and our previous report showed that Reg IV upregulated SOX9 expression and enhanced cell migration and invasion in gastric cancer cells. However, the regulatory roles of CDX2 have not been clarified in gastric cancer, and the correlation between CDX2 and Reg IV requires further study. Methods CDX2 and Reg IV were examined in gastric cancer specimens and paired adjacent tissues via real-time PCR and immunohistochemistry (IHC). The association between CDX2 and Reg IV was assessed using the χ2-test and Spearman’s rank correlation. To verify their relationship, knockdown and exogenous expression of CDX2 or Reg IV were performed in AGS and MKN-45 gastric cancer cells, and their expression was subsequently analyzed via a real-time PCR and western blotting. Wound-healing and Transwell assays were used to examine migration and invasion in AGS and MKN-45 cells following CDX2 silencing or overexpression. Results A positive correlation was observed between CDX2 and Reg IV expression at the mRNA and protein levels in gastric cancer tissues. CDX2 silencing significantly downregulated Reg IV expression, and CDX2 overexpression significantly upregulated Reg IV expression in AGS and MKN-45 cells. Neither Reg IV silencing nor overexpression had any effect on CDX2 protein expression in AGS or MKN-45 cells, even though both affected the expression of CDX2 mRNA. Functionally, CDX2 silencing significantly inhibited cell migration and invasion, and CDX2 overexpression significantly promoted cell migration and invasion in AGS and MKN-45 cells. Conclusions Our findings demonstrate that CDX2 expression was positively correlated with that of Reg IV in gastric cancer, and CDX2 promoted cell migration and invasion through upregulation of Reg IV expression in AGS and MKN-45 cells.

scholarly journals ZIC1 Is a Putative Tumor Suppressor in Thyroid Cancer by Modulating Major Signaling Pathways and Transcription Factor FOXO3a

2014 ◽  
Vol 99 (7) ◽  
pp. E1163-E1172 ◽  
Author(s):  
Wei Qiang ◽  
Yuan Zhao ◽  
Qi Yang ◽  
Wei Liu ◽  
Haixia Guan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Transcription Factor ◽  
Thyroid Cancer ◽  
Tumor Suppressor ◽  
Cancer Cells ◽  
Colony Formation ◽  
Promoter Hypermethylation ◽  
Migration And Invasion ◽  
Thyroid Cancer Cells

Context: ZIC1 has been reported to be overexpressed and plays an oncogenic role in some brain tumors, whereas it is inactivated by promoter hypermethylation and acts as a tumor suppressor in gastric and colorectal cancers. However, until now, its biological role in thyroid cancer remains totally unknown. Objectives: The aim of this study is to explore the biological functions and related molecular mechanism of ZIC1 in thyroid carcinogenesis. Setting and Design: Quantitative RT-PCR (qRT-PCR) was performed to evaluate mRNA expression of investigated genes. Methylation-specific PCR was used to analyze promoter methylation of the ZIC1 gene. The functions of ectopic ZIC1 expression in thyroid cancer cells were determined by cell proliferation and colony formation, cell cycle and apoptosis, as well as cell migration and invasion assays. Results: ZIC1 was frequently down-regulated by promoter hypermethylation in both primary thyroid cancer tissues and thyroid cancer cell lines. Moreover, our data showed that ZIC1 hypermethylation was significantly associated with lymph node metastasis in patients with papillary thyroid cancer. Notably, restoration of ZIC1 expression in thyroid cancer cells dramatically inhibited cell proliferation, colony formation, migration and invasion, and induced cell cycle arrest and apoptosis by blocking the activities of the phosphatidylinositol-3-kinase (PI3K)/Akt and RAS/RAF/MEK/ERK (MAPK) pathways, and enhancing FOXO3a transcriptional activity. Conclusions: Our data demonstrate that ZIC1 is frequently inactivated by promoter hypermethyaltion and functions as a tumor suppressor in thyroid cancer through modulating PI3K/Akt and MAPK signaling pathways and transcription factor FOXO3a.

scholarly journals SPNS2 Downregulation Induces EMT and Promotes Colorectal Cancer Metastasis via Activating AKT Signaling Pathway

2021 ◽  
Vol 11 ◽  
Author(s):  
Lei Lv ◽  
Qiyi Yi ◽  
Ying Yan ◽  
Fengmei Chao ◽  
Ming Li
Keyword(s):  
Colorectal Cancer ◽  
Molecular Mechanisms ◽  
Cancer Metastasis ◽  
Epithelial Mesenchymal Transition ◽  
Ectopic Expression ◽  
Migration And Invasion ◽  
Akt Inhibitor ◽  
Colon Adenoma ◽  
Mesenchymal Transition

Spinster homologue 2 (SPNS2), a transporter of S1P (sphingosine-1-phosphate), has been reported to mediate immune response, vascular development, and pathologic processes of diseases such as cancer via S1P signaling pathways. However, its biological functions and expression profile in colorectal cancer (CRC) is elusive. In this study, we disclosed that SPNS2 expression, which was regulated by copy number variation and DNA methylation of its promoter, was dramatically upregulated in colon adenoma and CRC compared to normal tissues. However, its expression was lower in CRC than in colon adenoma, and low expression of SPN2 correlated with advanced T/M/N stage and poor prognosis in CRC. Ectopic expression of SPNS2 inhibited cell proliferation, migration, epithelial–mesenchymal transition (EMT), invasion, and metastasis in CRC cell lines, while silencing SPNS2 had the opposite effects. Meanwhile, measuring the intracellular and extracellular level of S1P after overexpression of SPNS2 pinpointed a S1P-independent model of SPNS2. Mechanically, SPNS2 led to PTEN upregulation and inactivation of Akt. Moreover, AKT inhibitor (MK2206) abrogated SPNS2 knockdown-induced promoting effects on the migration and invasion, while AKT activator (SC79) reversed the repression of migration and invasion by SPNS2 overexpression in CRC cells, confirming the pivotal role of AKT for SPNS2’s function. Collectively, our study demonstrated the suppressor role of SPNS2 during CRC metastasis, providing new insights into the pathology and molecular mechanisms of CRC progression.

scholarly journals A Novel Therapeutic Target, BACH1, Regulates Cancer Metabolism

2021 ◽  
Author(s):  
Jiyoung Lee ◽  
Joselyn Padilla
Keyword(s):  
Cancer Cells ◽  
Cancer Patients ◽  
Transcriptional Activation ◽  
Pyruvate Dehydrogenase ◽  
Therapeutic Target ◽  
Metabolic Pathways ◽  
Cancer Metabolism ◽  
Aerobic Glycolysis ◽  
Pyruvate Dehydrogenase Kinase ◽  
Migration And Invasion

BTB domain and CNC homology 1 (BACH1) is a highly expressed transcription factor in tumors including breast and lung, relative to their non-tumor tissues. BACH1 is known to regulate multiple physiological processes including heme homeostasis, oxidative stress response, senescence, cell cycle, and mitosis. In a tumor, BACH1 promotes invasion and metastasis of cancer cells, and the expression of BACH1 presents a poor outcome for cancer patients including breast cancer patients. Recent studies identified novel functional roles of BACH1 in the regulation of metabolic pathways in cancer cells. BACH1 inhibits mitochondrial metabolism through transcriptional suppression of mitochondrial membrane genes. In addition, BACH1 suppresses activity of pyruvate dehydrogenase (PDH), a key enzyme that converts pyruvate to acetyl-CoA for the citric acid (TCA) cycle through transcriptional activation of pyruvate dehydrogenase kinase (PDK). Moreover, BACH1 increases glucose uptake and lactate secretion in aerobic glycolysis through the expression of metabolic enzymes involved such as hexokinase 2 (HK2) and glyceraldehyde 3- phosphate dehydrogenase (GAPDH). Pharmacological or genetic inhibition of BACH1 could reprogramme metabolic pathways, subsequently rendering metabolic vulnerability of cancer cells. Furthermore, inhibition of BACH1 decreased antioxidant-induced glycolysis rates as well as reduced migration and invasion of cancer cells, suggesting BACH1 as a potentially useful cancer therapeutic target.

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