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1.
Braz. j. med. biol. res ; 54(5): e10637, 2021. tab, graf
Article in English | LILACS | ID: biblio-1153548

ABSTRACT

Transcription factors control, coordinate, and separate the functions of distinct network modules spatially and temporally. In this review, we focus on the transcription factor 21 (TCF21) network, a highly conserved basic-helix-loop-helix (bHLH) protein that functions to integrate signals and modulate gene expression. We summarize the molecular and biological properties of TCF21 control with an emphasis on molecular and functional TCF21 interactions. We suggest that these interactions serve to modulate the development of different organs at the transcriptional level to maintain growth homeostasis and to influence cell fate. Importantly, TCF21 expression is epigenetically inactivated in different types of human cancers. The epigenetic modification or activation and/or loss of TCF21 expression results in an imbalance in TCF21 signaling, which may lead to tumor initiation and, most likely, to progression and tumor metastasis. This review focuses on research on the roles of TCF21 in development and tumorigenesis systematically considering the physiological and pathological function of TCF21. In addition, we focus on the main molecular bases of its different roles whose importance should be clarified in future research. For this review, PubMed databases and keywords such as TCF21, POD-1, capsulin, tumors, carcinomas, tumorigenesis, development, and mechanism of action were utilized. Articles were selected within a historical context as were a number of citations from journals with relevant impact.


Subject(s)
Humans , Basic Helix-Loop-Helix Transcription Factors/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , Carcinogenesis/genetics , Signal Transduction , Cell Differentiation , Cell Transformation, Neoplastic/genetics
2.
Biol. Res ; 53: 25, 2020. tab, graf
Article in English | LILACS | ID: biblio-1124210

ABSTRACT

BACKGROUND: Hypoxia inducible factor-1 (HIF-1) is considered as the most activated transcriptional factor in response to low oxygen level or hypoxia. HIF-1 binds the hypoxia response element (HRE) sequence in the promoter of different genes, mainly through the bHLH domain and activates the transcription of genes, especially those involved in angiogenesis and EMT. Considering the critical role of bHLH in binding HIF-1 to the HRE sequence, we hypothesized that bHLH could be a promising candidate to be targeted in hypoxia condition. METHODS: We inserted an inhibitory bHLH (ibHLH) domain in a pIRES2-EGFP vector and transfected HEK293T cells with either the control vector or the designed construct. The ibHLH domain consisted of bHLH domains of both HIF-1a and Arnt, capable of competing with HIF-1 in binding to HRE sequences. The transfected cells were then treated with 200 µM of cobalt chloride (CoCl2) for 48 h to induce hypoxia. Real-time PCR and western blot were performed to evaluate the effect of ibHLH on the genes and proteins involved in angiogenesis and EMT. RESULTS: Hypoxia was successfully induced in the HEK293T cell line as the gene expression of VEGF, vimentin, and ß-catenin were significantly increased after treatment of untransfected HEK293T cells with 200 µM CoCl2. The gene expression of VEGF, vimentin, and ß-catenin and protein level of ß-catenin were significantly decreased in the cells transfected with either control or ibHLH vectors in hypoxia. However, ibHLH failed to be effective on these genes and the protein level of ß-catenin, when compared to the control vector. We also observed that overexpression of ibHLH had more inhibitory effect on gene and protein expression of N-cadherin compared to the control vector. However, it was not statistically significant. CONCLUSION: bHLH has been reported to be an important domain involved in the DNA binding activity of HIF. However, we found that targeting this domain is not sufficient to inhibit the endogenous HIF-1 transcriptional activity. Further studies about the function of critical domains of HIF-1 are necessary for developing a specific HIF-1 inhibitor.


Subject(s)
Humans , Basic Helix-Loop-Helix Transcription Factors/metabolism , Hypoxia-Inducible Factor 1/metabolism , Hypoxia/metabolism , Gene Expression , Transcriptional Activation/genetics , Blotting, Western , Basic Helix-Loop-Helix Transcription Factors/genetics , Hypoxia-Inducible Factor 1/genetics , HEK293 Cells , Real-Time Polymerase Chain Reaction , Hypoxia/genetics
3.
Braz. j. med. biol. res ; 51(7): e6201, 2018. tab, graf
Article in English | LILACS | ID: biblio-889119

ABSTRACT

This study aimed to investigate the role of hypoxia-inducible factor-2α (HIF-2α) in the expression of tight junction proteins and permeability alterations in rat glomerular endothelial cells (rGENCs) under hypoxia conditions. The expression level of HIF-2α and tight junction proteins (occludin and ZO-1) in rGENCs were examined following 5% oxygen density exposure at different treatment times. HIF-2α lentivirus transfection was used to knockdown HIF-2α expression. Cells were divided into four groups: 1) control group (rGENCs were cultured under normal oxygen conditions), 2) hypoxia group (rGENCs were cultured under hypoxic conditions), 3) negative control group (rGENCs were infected with HIF-2α lentivirus negative control vectors and cultured under hypoxic conditions), and 4) Len group (rGENCs were transfected with HIF-2α lentivirus and cultured under hypoxic conditions). The hypoxia, negative control, and Len groups were kept in a hypoxic chamber (5% O2, 5% CO2, and 90% N2) for 24 h and the total content of occludin and ZO-1, and the permeability of rGENCs were assessed. With increasing hypoxia time, the expression of HIF-2α gradually increased, while the expression of occludin decreased, with a significant difference between groups. ZO-1 expression gradually decreased under hypoxia conditions, but the difference between the 24 and 48 h groups was not significant. The permeability of cells increased following 24-h exposure to hypoxia compared to the control group (P<0.01). The knockdown of HIF-2α expression significantly increased occludin and ZO-1 content compared with hypoxia and negative control groups (P<0.01), while permeability was reduced (P<0.01). Hypoxia increased HIF-2α content, inducing permeability of rGENCs through the reduced expression of occludin and ZO-1.


Subject(s)
Animals , Rats , Endothelial Cells/chemistry , Basic Helix-Loop-Helix Transcription Factors/metabolism , Occludin/metabolism , Zonula Occludens-1 Protein/metabolism , Kidney Glomerulus/cytology , Permeability , Time Factors , Cell Hypoxia/physiology , Endothelial Cells/metabolism , Cell Proliferation
4.
Clinics ; 72(6): 391-394, June 2017. graf
Article in English | LILACS | ID: biblio-840089

ABSTRACT

OBJECTIVES: Transcription Factor 21 represses steroidogenic factor 1, a nuclear receptor required for gonadal development, sex determination and the regulation of adrenogonadal steroidogenesis. The aim of this study was to investigate whether silencing or overexpression of the gene Transcription Factor 21 could modulate the gene and protein expression of steroidogenic factor 1 in adrenocortical tumors. METHODS: We analyzed the gene expression of steroidogenic factor 1 using qPCR after silencing endogenous Transcription Factor 21 in pediatric adrenal adenoma-T7 cells through small interfering RNA. In addition, using overexpression of Transcription Factor 21 in human adrenocortical carcinoma cells, we analyzed the protein expression of steroidogenic factor 1 using Western blotting. RESULTS: Transcription Factor 21 knockdown increased the mRNA expression of steroidogenic factor 1 by 5.97-fold in pediatric adrenal adenoma-T7 cells. Additionally, Transcription Factor 21 overexpression inhibited the protein expression of steroidogenic factor 1 by 0.41-fold and 0.64-fold in two different adult adrenocortical carcinoma cell cultures, H295R and T36, respectively. CONCLUSIONS: Transcription Factor 21 is downregulated in adrenocortical carcinoma cells. Taken together, these findings support the hypothesis that Transcription Factor 21 is a regulator of steroidogenic factor 1 and is a tumor suppressor gene in pediatric and adult adrenocortical tumors.


Subject(s)
Humans , Adrenal Cortex Neoplasms/metabolism , Basic Helix-Loop-Helix Transcription Factors/metabolism , Gene Expression Regulation, Neoplastic/genetics , Steroidogenic Factor 1/metabolism , Adrenal Cortex Neoplasms/genetics , Basic Helix-Loop-Helix Transcription Factors/genetics , Blotting, Western , Cell Line, Tumor , Down-Regulation , Immunoblotting , Real-Time Polymerase Chain Reaction , Steroidogenic Factor 1/genetics
5.
Yonsei Medical Journal ; : 735-740, 2016.
Article in English | WPRIM | ID: wpr-21839

ABSTRACT

PURPOSE: The aim of this study was to determine the relationship of hypoxia-inducible factor-2 (HIF-2α) and vascular endothelial growth factor (VEGF) with radiographic severity in primary osteoarthritis (OA) of the knee. Expression of these two factors in cartilage samples from OA knee joints was examined at mRNA and protein levels. MATERIALS AND METHODS: Knee joints were examined using plain radiographs, and OA severity was assessed using the Kellgren and Lawrence (KL) grading system. Specimens were collected from 29 patients (31 knees) who underwent total knee replacement because of severe medial OA of the knee (KL grades 3 and 4), 16 patients who underwent knee arthroscopy (KL grade 2), and 5 patients with traumatic knees (KL grade 0). HIF-2α and VEGF expression was quantified by real-time polymerase chain reaction and western blotting. RESULTS: Cartilage degeneration correlated with the radiographic severity grade. OA severity, determined using the Mankin scale, correlated positively with the KL grade (r=0.8790, p<0.01), and HIF-2α and VEGF levels with the radiographic severity of knee OA (r=0.7001, p<0.05; r=0.6647, p<0.05). CONCLUSION: In OA cartilage, HIF-2α and VEGF mRNA and protein levels were significantly and positively correlated. The expression of both factors correlated positively with the KL grade. HIF-2α and VEGF, therefore, may serve as biochemical markers as well as potential therapeutic targets in knee OA.


Subject(s)
Adult , Aged , Arthroplasty, Replacement, Knee , Arthroscopy , Basic Helix-Loop-Helix Transcription Factors/metabolism , Biomarkers/blood , Cartilage/metabolism , Female , Humans , Knee Joint/diagnostic imaging , Male , Middle Aged , Osteoarthritis, Knee/blood , RNA, Messenger , Radiography , Real-Time Polymerase Chain Reaction , Severity of Illness Index , Vascular Endothelial Growth Factor A/metabolism
6.
Braz. j. med. biol. res ; 48(12): 1087-1094, Dec. 2015. graf
Article in English | LILACS | ID: lil-762914

ABSTRACT

During gonad and adrenal development, the POD-1/capsulin/TCF21transcription factor negatively regulates SF-1/NR5A1expression, with higher SF-1 levels being associated with increased adrenal cell proliferation and tumorigenesis. In adrenocortical tumor cells, POD-1 binds to the SF-1 E-box promoter region, decreasing SF-1 expression. However, the modulation of SF-1 expression by POD-1 has not previously been described in normal adrenal cells. Here, we analyzed the basal expression of Pod-1 and Sf-1 in primary cultures of glomerulosa (G) and fasciculata/reticularis (F/R) cells isolated from male Sprague-Dawley rats, and investigated whether POD-1 overexpression modulates the expression of endogenous Sf-1 and its target genes in these cells. POD-1 overexpression, following the transfection of pCMVMycPod-1, significantly decreased the endogenous levels of Sf-1 mRNA and protein in F/R cells, but not in G cells, and also decreased the expression of the SF-1 target StAR in F/R cells. In G cells overexpressing POD-1, no modulation of the expression of SF-1 targets, StAR and CYP11B2, was observed. Our data showing that G and F/R cells respond differently to ectopic POD-1 expression emphasize the functional differences between the outer and inner zones of the adrenal cortex, and support the hypothesis that SF-1 is regulated by POD-1/Tcf21 in normal adrenocortical cells lacking the alterations in cellular physiology found in tumor cells.


Subject(s)
Animals , Male , Adrenal Cortex/metabolism , Basic Helix-Loop-Helix Transcription Factors/metabolism , Phosphoproteins/metabolism , Steroidogenic Factor 1/metabolism , Adrenal Cortex/cytology , Basic Helix-Loop-Helix Transcription Factors/genetics , Electrophoresis, Polyacrylamide Gel , Gene Expression , Immunoblotting , Primary Cell Culture , Phosphoproteins/analysis , Rats, Sprague-Dawley , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , RNA, Messenger/analysis , Steroidogenic Factor 1/analysis , Zona Fasciculata/cytology , Zona Fasciculata/metabolism , Zona Glomerulosa/cytology , Zona Glomerulosa/metabolism , Zona Reticularis/cytology , Zona Reticularis/metabolism
7.
Clinics ; 68(5): 592-598, maio 2013. tab, graf
Article in English | LILACS | ID: lil-675756

ABSTRACT

OBJECTIVE: To analyze the expression of hypoxia-inducible factors (hypoxia-inducible factor 1A and hypoxia-inducible factor 2A) and aldehyde dehydrogenase proteins in patients with locally advanced breast carcinoma who were subjected to neoadjuvant chemotherapy. METHODS: We included 90 patients with histologically confirmed stage II and III breast carcinoma who were treated with neoadjuvant chemotherapy between 2000 and 2005. Immunohistochemistry for aldehyde dehydrogenase, hypoxia-inducible factor 1A, and hypoxia-inducible factor 2A was performed before and after neoadjuvant chemotherapy. We analyzed the influence of clinical and pathological features on clinical and pathological response, disease-free survival, and overall survival. RESULTS: An objective clinical response to neoadjuvant chemotherapy was observed in 80% of patients, with 12% showing a complete pathological response. Among all clinical and pathological parameters, only the expression of hypoxia-inducible factor 1A was associated with a pathological response. A positive association was found between expression of aldehyde dehydrogenase and that of hypoxia-inducible factor 1A before and after chemotherapy. Aldehyde dehydrogenase expression was associated with expression of hypoxia inducible-factor 2A in tumors after neoadjuvant treatment. In a univariate analysis, prognosis was influenced by age, pathological response, metastasis to axillary lymph nodes after neoadjuvant chemotherapy, overexpression of hypoxia-inducible factor 2, and the presence of aldehyde dehydrogenase-positive cells within the primary tumor after neoadjuvant chemotherapy. In a multivariate analysis, only age and the presence of aldehyde dehydrogenase-positive cells after chemotherapy were associated with reduced overall survival. CONCLUSION: The presence of aldehyde dehydrogenase-positive cells within the residual tumor after neoadjuvant chemotherapy is associated with an increase in the expression ...


Subject(s)
Female , Humans , Middle Aged , Aldehyde Dehydrogenase/metabolism , Basic Helix-Loop-Helix Transcription Factors/metabolism , Breast Neoplasms/metabolism , Hypoxia-Inducible Factor 1/metabolism , Antineoplastic Combined Chemotherapy Protocols , Breast Neoplasms/drug therapy , Breast Neoplasms/mortality , Breast Neoplasms/pathology , Disease-Free Survival , Immunohistochemistry , Neoadjuvant Therapy , Neoplasm Staging , Prognosis , Prospective Studies
8.
Article in English | WPRIM | ID: wpr-27757

ABSTRACT

As glucose is known to induce insulin secretion in pancreatic beta cells, this study investigated the role of a phospholipase D (PLD)-related signaling pathway in insulin secretion caused by high glucose in the pancreatic beta-cell line MIN6N8. It was found that the PLD activity and PLD1 expression were both increased by high glucose (33.3 mM) treatment. The dominant negative PLD1 inhibited glucose-induced Beta2 expression, and glucose-induced insulin secretion was blocked by treatment with 1-butanol or PLD1-siRNA. These results suggest that high glucose increased insulin secretion through a PLD1-related pathway. High glucose induced the binding of Arf6 to PLD1. Pretreatment with brefeldin A (BFA), an Arf inhibitor, decreased the PLD activity as well as the insulin secretion. Furthermore, BFA blocked the glucose-induced mTOR and p70S6K activation, while mTOR inhibition with rapamycin attenuated the glucose induced Beta2 expression and insulin secretion. Thus, when taken together, PLD1 would appear to be an important regulator of glucose-induced insulin secretion through an Arf6/PLD1/mTOR/p70S6K/Beta2 pathway in MIN6N8 cells.


Subject(s)
ADP-Ribosylation Factors/metabolism , Animals , Basic Helix-Loop-Helix Transcription Factors/metabolism , Cells, Cultured , Gene Expression Regulation, Enzymologic/drug effects , Glucose/pharmacology , Insulin/metabolism , Insulin-Secreting Cells/drug effects , Intracellular Signaling Peptides and Proteins/metabolism , Mice , Models, Biological , Oligodeoxyribonucleotides, Antisense/pharmacology , Phospholipase D/antagonists & inhibitors , Protein-Serine-Threonine Kinases/metabolism , Ribosomal Protein S6 Kinases, 70-kDa/metabolism , Signal Transduction/drug effects
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