Immune modulation of Th1/Th2/Treg/Th17/Th9/Th21 cells in rabbits infected with Eimeria stiedai

Introduction

Despite long-term integrated control programs for Eimeria stiedai infection in China, hepatic coccidiosis in rabbits persists. Th1, Th2, Th17, Treg, Th9, and Th21 cells are involved in immune responses during pathogen infection. It is unclear whether Th cell subsets are also involved in E. stiedai infection. Their roles in the immunopathology of this infection remain unknown. Therefore, monitoring these T-cell subsets' immune responses during primary infection of E. stiedai at both transcriptional (mRNA) and protein (cytokines) levels is essential.

Methods

In experimentally infected New Zealand white rabbits, mRNA expression levels of their transcript-TBX2 (Th1), GATA3 (Th2), RORC (Th17), Foxp3 (Treg), SPI1 (Th9), and BCL6 (Th21)-were evaluated using quantitative real-time polymerase chain reaction (qRT-PCR), whereas Th1 (IFN-g and TNF-a), Th2 (IL4), Th17 (IL17A and IL6), Treg (IL10 and TGF-b1), Th9 (IL9), and Th21 (IL21) cytokines were measured using enzyme-linked immunosorbent assays (ELISAs).

Results

We found that levels of TBX2, GATA3, RORC, SPI1, and BCL6 in the livers of infected rabbits were elevated on days 5 and 15 post-infection (PI). The concentrations of their distinctive cytokines IFN-g and TNF-a for Th1, IL4 for Th2, IL17A for Th17, IL9 for Th9, IL21 for Th21, and IL10 for Treg IL10 were also significantly increased on days 5 and 15 PI, respectively (p < 0.05). On day 23 PI, GATA3 with its cytokine IL4, RORC with IL17A, Foxp3 with IL10 and TGF-b1, and SPI1 with IL9 were significantly decreased, but TBX2 with IFN-g and IL6 remained elevated.

Discussion

Our findings are the first evidence of Th1/Th2/Treg/Th17/Th9/Th21 changes in E. stiedai-infected rabbits and provide insights into immune regulation mechanisms and possible vaccine development.

miR-486-5p Attenuates Steroid-Induced Adipogenesis and Osteonecrosis of the Femoral Head Via TBX2/P21 Axis

Enhanced adipogenic differentiation of mesenchymal stem cells (MSCs) is considered as a major risk factor for steroid-induced osteonecrosis of the femoral head (SOFNH). The role of microRNAs during this process has sparked interest. miR-486-5p expression was down-regulated significantly in femoral head bone tissues of both SONFH patients and rat models. The purpose of this study was to reveal the role of miR-486-5p on MSCs adipogenesis and SONFH progression. The present study showed that miR-486-5p could significantly inhibit adipogenesis of 3T3-L1 cells by suppressing mitotic clonal expansion (MCE). And upregulated expression of P21, which was caused by miR-486-5p mediated TBX2 decrease, was responsible for inhibited MCE. Further, miR-486-5p was demonstrated to effectively inhibit steroid-induced fat formation in the femoral head and prevented SONFH progression in a rat model. Considering the potent effects of miR-486-5p on attenuating adipogenesis, it seems to be a promising target for the treatment of SONFH.

Case report: A novel de novo loss of function variant in the DNA-binding domain of TBX2 causes severe osteochondrodysplasia

Background: T-box family members are transcription factors characterized by highly conserved residues corresponding to the DNA-binding domain known as the T-box. TBX2 has been implicated in several developmental processes, such as coordinating cell fate, patterning, and morphogenesis of a wide range of tissues and organs, including lungs, limbs, heart, kidneys, craniofacial structures, and mammary glands. Methods: In the present study, we have clinically and genetically characterized a proband showing a severe form of chondrodysplasia with developmental delay. Whole-exome sequencing (WES), Sanger sequencing, and 3D protein modeling were performed in the present investigation. Results: Whole-exome sequencing revealed a novel nonsense variant (c.529A>T; p.Lys177*; NM_005994.4) in TBX2. 3D-TBX2 protein modeling revealed a substantial reduction of the mutated protein, which might lead to a loss of function (LOF) or nonsense-mediated decay (NMD). Conclusion: This study has not only expanded the mutation spectrum in the gene TBX2 but also facilitated the diagnosis and genetic counseling of related features in affected families.

T-box transcription factor 2 mediates antitumor immune response in cutaneous squamous cell carcinoma by regulating the expression of programmed death ligand 1

BACKGROUND

Cutaneous squamous cell carcinoma (CSCC) is the second largest nonmelanoma skin cancer in humans; effective treatment options for metastatic CSCC are still in short. In this study, we aimed to explore the function of T-box transcription factor 2 (TBX2) in CSCC.

METHODS

The expression level of TBX2 was determined in CSCC samples and cell lines. Programmed death ligand 1 (PD-L1) expression was also analyzed in human CSCC samples. Furthermore, SCC13 cells were transfected with TBX2-DN (loss of function) or normal TBX2 to check its role in regulating PD-L1.

RESULTS

The expression level of TBX2 was positively correlated with the stage of CSCC. CSCC tumor cell lines have significantly higher expression levels of TBX2 than normal skin cell lines, and SCC13 cells showed the highest expression. PD-L1 expressions were upregulated during the progression of CSCC, and positively correlated with TBX2. Furthermore, PD-L1 expression increased in SCC13 cells overexpressing TBX2. However, TBX2 did not regulate the activation of IFNγ signal, but mediated the expression of interferon regulatory factor 1 (IRF1) and PD-L1 in both SCC13 and PDV cells.

CONCLUSION

TBX2 could mediate antitumor immune response in CSCC by regulating the expression of PD-L1 through IRF1. It might be a prognostic marker in CSCC and synergistic target for PD-1 immunotherapy.

Clinical and Genetic Characteristics of Preeclampsia

Preeclampsia (PE) is a severe complication of pregnancy accompanied by arterial hypertension, edema, or proteinuria with impaired functioning of various organs and systems. It is also an important medical and social problem, which has been one of the leading causes of maternal and perinatal mortality and morbidity worldwide. Despite the achievements of modern medicine, the etiology of this pathology is still unknown. Recently, many scientists have especially focused on the study of genetic factors underlying the etiopathogenesis of PE, namely, the contribution of individual polymorphic loci of various candidate genes. The current study aimed to investigate the clinical characteristics of PE and the contribution of the polymorphic loci rs1042838 of Progesterone Receptor (PGR) gene and rs8068318 of the T-Box Transcription Factor 2 (TBX2) gene to the development of PE. The study was conducted on 219 women with PE with the mean±SD age of 26.52±5.51 years and 329 women with the physiological course of pregnancy as the control group with the mean±SD age of 26.27±4.88 years. In total, 64.20%, 68.29%, 16.44%, 98.63%, and 35.48% of women with PE had increased systolic and normal diastolic blood pressure (SBP and DBP) values, proteinuria, edema, and overweight (BMI≥25), respectively. In the control group, 100%, 1.53%, 1.12%, and 35.48% of cases had normal SBP values with no proteinuria, DBP>90 mm Hg, edema, and overweight (BMI≥25), respectively. An association was observed between the CC genotype of the rs8068318 polymorphism of the TBX2 gene with the risk of developing PE in women with PE (OR=2.12, 95%CI: 1.14-3.92, P=0.02). In addition, there was an association between the rs8068318 TBX2 polymorphic locus with lower SBP (Me=140, Q25 - Q75 130 - 142.5, P=0.01) and PBP (Me=50, Q25 - Q75 40 - 55, P<0.01). According to the GeneCards database, the TBX2 gene, a member of a phylogenetically conserved gene family, is located on the long arm of chromosome 17 and encodes the TBX2 T-box transcription factor protein, which is a regulator of the transcriptional activity of various genes (i.e., it suppresses the expression of CDKN2A (p19/ARF), inhibits cyclin-dependent kinase p21 Cip1 (CDKN1A), and affects the expression of MYC, RAS, BRCA1, and BRCA2 genes).

A Novel Osteochondrodysplasia With Empty Sella Associates With a TBX2 Variant

Skeletal dysplasias comprise a heterogenous group of developmental disorders of skeletal and cartilaginous tissues. Several different forms have been described and the full spectrum of their clinical manifestations and underlying genetic causes are still incompletely understood. We report a three-generation Finnish family with an unusual, autosomal dominant form of osteochondrodysplasia and an empty sella. Affected individuals (age range 24-44 years) exhibit unusual codfish-shaped vertebrae, severe early-onset and debilitating osteoarthritis and an empty sella without endocrine abnormalities. Clinical characteristics also include mild dysmorphic features, reduced sitting height ratio, and obesity. Whole-exome sequencing excluded known skeletal dysplasias and identified a novel heterozygous missense mutation c.899C>T (p.Thr300Met) in TBX2, confirmed by Sanger sequencing. TBX2 is important for development of the skeleton and the brain and three prior reports have described variations in TBX2 in patients portraying a complex phenotype with vertebral anomalies, craniofacial dysmorphism and endocrine dysfunctions. Our mutation lies near a previously reported disease-causing variant and is predicted pathogenic with deleterious effects on protein function. Our findings expand the current spectrum of skeletal dysplasias, support the association of TBX2 mutations with skeletal dysplasia and suggest a role for TBX2 in development of the spinal and craniofacial structures and the pituitary gland.

TBX2 controls a proproliferative gene expression program in melanoma

Senescence shapes embryonic development, plays a key role in aging, and is a critical barrier to cancer initiation, yet how senescence is regulated remains incompletely understood. TBX2 is an antisenescence T-box family transcription repressor implicated in embryonic development and cancer. However, the repertoire of TBX2 target genes, its cooperating partners, and how TBX2 promotes proliferation and senescence bypass are poorly understood. Here, using melanoma as a model, we show that TBX2 lies downstream from PI3K signaling and that TBX2 binds and is required for expression of E2F1, a key antisenescence cell cycle regulator. Remarkably, TBX2 binding in vivo is associated with CACGTG E-boxes, present in genes down-regulated by TBX2 depletion, more frequently than the consensus T-element DNA binding motif that is restricted to Tbx2 repressed genes. TBX2 is revealed to interact with a wide range of transcription factors and cofactors, including key components of the BCOR/PRC1.1 complex that are recruited by TBX2 to the E2F1 locus. Our results provide key insights into how PI3K signaling modulates TBX2 function in cancer to drive proliferation.

TBX2 Drives Neuroendocrine Prostate Cancer through Exosome-Mediated Repression of miR-200c-3p

Simple Summary

An estimated ~25–30% of patients with advanced prostate cancer (PCa) develop the aggressive and lethal form of the disease known as treatment-induced neuroendocrine prostate cancer (t-NEPC). Owing to lack of treatment options, the identification of the underlying molecular mechanisms that propagate the t-NEPC phenotype is critical towards developing novel therapeutic strategies against advanced PCa. Further, the roles of extracellular vesicles (exosomes) and microRNAs—an increasingly recognized and key mode of propagation of the NEPC phenotype—remain elusive. Our studies reveal that TBX2 promotes SOX2- and N-MYC- driven t-NEPC through regulation of the intermediary factor—miR-200c-3p; and that TBX2/miR-200c-3p/SOX2/MYCN signaling can promote t-NEPC via both intracellular and exosome-mediated intercellular mechanisms.

Abstract

Deciphering the mechanisms that drive transdifferentiation to neuroendocrine prostate cancer (NEPC) is crucial to identifying novel therapeutic strategies against this lethal and aggressive subtype of advanced prostate cancer (PCa). Further, the role played by exosomal microRNAs (miRs) in mediating signaling mechanisms that propagate the NEPC phenotype remains largely elusive. The unbiased differential miR expression profiling of human PCa cells genetically modulated for TBX2 expression led to the identification of miR-200c-3p. Our findings have unraveled the TBX2/miR-200c-3p/SOX2/N-MYC signaling axis in NEPC transdifferentiation. Mechanistically, we found that: (1) TBX2 binds to the promoter and represses the expression of miR-200c-3p, a miR reported to be lost in castrate resistant prostate cancer (CRPC), and (2) the repression of miR-200c-3p results in the increased expression of its targets SOX2 and N-MYC. In addition, the rescue of mir-200c-3p in the context of TBX2 blockade revealed that miR-200c-3p is the critical intermediary effector in TBX2 regulation of SOX2 and N-MYC. Further, our studies show that in addition to the intracellular mode, TBX2/miR-200c-3p/SOX2/N-MYC signaling can promote NEPC transdifferentiation via exosome-mediated intercellular mechanism, an increasingly recognized and key mode of propagation of the NEPC phenotype.

TBX2, a Novel Regulator of Labour

Background and Objectives: Therapeutic interventions targeting molecular factors involved in the transition from uterine quiescence to overt labour are not substantially reducing the rate of spontaneous preterm labour. The identification of novel rational therapeutic targets are essential to prevent the most common cause of neonatal mortality. Based on our previous work showing that Tbx2 (T-Box transcription factor 2) is a putative upstream regulator preceding progesterone withdrawal in mouse myometrium, we now investigate the role of TBX2 in human myometrium. Materials and Methods: RNA microarray analysis of (A) preterm human myometrium samples and (B) myometrial cells overexpressing TBX2 in vitro, combined with subsequent analysis of the two publicly available datasets of (C) Chan et al. and (D) Sharp et al. The effect of TBX2 overexpression on cytokines/chemokines secreted to the myometrium cell culture medium were determined by Luminex assay. Results: Analysis shows that overexpression of TBX2 in myometrial cells results in downregulation of TNFα- and interferon signalling. This downregulation is consistent with the decreased expression of cytokines and chemokines of which a subset has been previously associated with the inflammatory pathways relevant for human labour. In contrast, CXCL5 (C-X-C motif chemokine ligand 5), CCL21 and IL-6 (Interleukin 6), previously reported in relation to parturition, do not seem to be under TBX2 control. The combined bioinformatical analysis of the four mRNA datasets identifies a subset of upstream regulators common to both preterm and term labour under control of TBX2. Surprisingly, TBX2 mRNA levels are increased in preterm contractile myometrium. Conclusions: We identified a subset of upstream regulators common to both preterm and term labour that are activated in labour and repressed by TBX2. The increased TBX2 mRNA expression in myometrium collected during a preterm caesarean section while in spontaneous preterm labour compared to tissue harvested during iatrogenic preterm delivery does not fit the bioinformatical model. We can only explain this by speculating that the in vivo activity of TBX2 in human myometrium depends not only on the TBX2 expression levels but also on levels of the accessory proteins necessary for TBX2 activity.

MicroRNA-7 targets T-Box 2 to inhibit epithelial-mesenchymal transition and invasiveness in glioblastoma multiforme

The dysregulation of microRNA expression in cancer has been associated with the epithelial-mesenchymal transition (EMT) that triggers invasive ability and increases therapeutic resistance. Here, we determined the microRNA expression profile of seven tumor tissues from patients with glioblastoma multiforme (GBM) by use of microRNA array analysis. We discovered that microRNA-7 (miR-7) is consistently downregulated in all tumor samples. Using the microRNA.org algorithm, the T-box 2 gene (TBX2) was identified as a candidate gene targeted by miR-7. In contrast to miR-7, TBX2 had an increased expression in GBM tumors and was linked to poor prognosis. We confirmed that TBX2 mRNA and protein production are significantly repressed by overexpressing miR-7 in GBM cells in vitro. The reporter assay showed that miR-7 significantly represses the signal from luciferase with the 3' UTR of TBX2. Furthermore, TBX2 overexpression decreased E-cadherin expression and increased Vimentin expression, causing an increasing number of invaded cells in the invasion assay, as well as pulmonary metastasis in vivo. Our findings demonstrated that overexpression of TBX2 in GBM tumors via the downregulation of miR-7 leads to EMT induction and increased cell invasion.

Loss of CHD1 Promotes Heterogeneous Mechanisms of Resistance to AR-Targeted Therapy via Chromatin Dysregulation

Metastatic prostate cancer is characterized by recurrent genomic copy number alterations that are presumed to contribute to resistance to hormone therapy. We identified CHD1 loss as a cause of antiandrogen resistance in an in vivo small hairpin RNA (shRNA) screen of 730 genes deleted in prostate cancer. ATAC-seq and RNA-seq analyses showed that CHD1 loss resulted in global changes in open and closed chromatin with associated transcriptomic changes. Integrative analysis of this data, together with CRISPR-based functional screening, identified four transcription factors (NR3C1, POU3F2, NR2F1, and TBX2) that contribute to antiandrogen resistance, with associated activation of non-luminal lineage programs. Thus, CHD1 loss results in chromatin dysregulation, thereby establishing a state of transcriptional plasticity that enables the emergence of antiandrogen resistance through heterogeneous mechanisms.

TBX2 Expression predicts Tumor Recurrence and Adjuvant Chemotherapy Benefits in Gastric Cancer Patients following R0 Resection: a proposed approach for risk stratification

Aims: TBX2 is related to tumor progression and drug resistance. However, the roles of TBX2 in gastric cancer (GC) remain unclear. Our study aims at investigating the clinical roles of TBX2 in GC.

Methods: The protein expression levels of TBX2 in fresh GC tissue (n=20) were investigated with Western blotting analyses. The correlation between TBX2 expression and its prognostic significance was evaluated by immunohistochemical analyses of 401 patients. The survival benefit of postoperative adjuvant chemotherapy (PAC) for patients was evaluated.

Results: The expression of TBX2 was increased in GC tissue compared with adjacent paracancerous tissue (p=0.020). Immunohistochemistry demonstrated that TBX2 expression was significantly associated with lymphovascular invasion (p=0.024) and lymph node metastasis (p=0.044). A high level of TBX2 expression was an independent indicator of unfavorable recurrence-free and overall survival (p=0.002 and p=0.033, respectively). The prognostic model incorporating TBX2 expression exhibited greater predictive accuracy than the primary model. More importantly, the benefit of PAC noted in stage II/III GC patients with low TBX2 expression was superior to high TBX2 expression.

Conclusion: TBX2 may be not only a useful prognostic marker for GC but also a predictive biomarker of response to PAC in stage II/III GC patients. The current findings warrant further verification.

TBX2 Identified as a Potential Predictor of Bone Metastasis in Lung Adenocarcinoma via Integrated Bioinformatics Analyses and Verification of Functional Assay

Objective: Bone metastasis from patients with advanced lung adenocarcinoma (LAC) is a very serious complication. To better understand the molecular mechanism, our current study sheds light on identification of hub genes mediating bone metastatic spread by combining bioinformatic analysis with functional verification. Methods: First, we downloaded a lung adenocarcinoma dataset (GSE76194) from Gene Expression Omnibus, analyzed differentially expressed genes (DEGs) through Limma package in R software and constructed a protein-protein interaction network. Based on that preliminary data, we further performed modular and topological analysis using Cystoscope to obtain biological connected genes. Through literature searching and performing mRNA expression analysis on the other independent public dataset (GSE10799), we finally focused on TBX2. Functional effects of TBX2 were performed in tumorigenicity assays including migration and invasion assays, cell proliferation assay, and cell cycle assay. In addition, mechanically, we found enriched pathways related to bone metastasis using Gene Set Enrichment Analysis (GSEA) and validated our results by western blot. Result: A total of 1132 significant genes were sorted initially. We selected common significant genes (log FC>2; p<0.01) from both the biological network data and microarray data. In total, 44 such genes were identified. we found TBX2, along with 10 other genes, to be reported with relevance to bone metastasis in other cancer types. Moreover, TBX2 showed significantly higher expression levels in patients that were found positive for metastasis to bone marrow compared to patients that did not exhibit this type of metastasis in the other separated cohort (GSE10799). Thus, we finally focused on TBX2. We found that TBX2 had detectable expression in LAC cell lines and silencing endogenous TBX2 expression in A549 and H1299 cell lines markedly suppressed migration and invasion, cell proliferation and arrested cell-cycle. Pathway enrichment analyses suggested that TBX2 drove LAC oncogenesis and metastasis through various pathways with epithelial mesenchymal transition (EMT) figuring prominently in the bone metastatic group, which was evidenced by western blot. Conclusion: Collectively, TBX2 plays as a potential predictor of bone metastasis from LAC, yielding a better promise view towards "driver" gene responsible for bone metastasis.

DREAM target reactivation by core transcriptional regulators supports neuroblastoma growth

Chromosome 17q gains are a common alteration in high-risk neuroblastomas with unknown functional significance. We identified a 17q super-enhancer regulated T-box Transcription Factor 2 (TBX2) as constituent of a core regulatory circuitry driving proliferation through enhancing V-myc myelocytomatosis viral-related oncogene, neuroblastoma derived (avian) (MYCN)/Forkhead box protein M1(FOXM1) reactivation of dimerization partner, RB-like, E2F and multi-vulval class B (DREAM) targets, which can be affected synergistically by combined cyclin-dependent kinase 7 and Bromo-domain inhibition.

Epigenetic Suppression of the T-box Subfamily 2 (TBX2) in Human Non-Small Cell Lung Cancer

(1) The TBX2 subfamily of transcription factors (TBXs 2, 3, 4 and 5) are markedly down-regulated in human non-small cell lung cancer (NSCLC) and exert tumor suppressor effects in lung malignancy. Yet, mechanisms underlying suppressed expression of the TBX2 subfamily in NSCLC are elusive. Here, we interrogated probable epigenetic mechanisms in suppressed expression of the TBX2 subfamily in human NSCLC. (2) TBX2 subfamily gene expression and methylation levels in NSCLC and normal lung tissues were surveyed using publicly available RNA-sequence and genome-wide methylation datasets. Methylation β-values of the four genes were statistically compared between NSCLCs and normal lung tissues, correlated with gene expression levels, and interrogated with clinicopathological variables. Expression and methylation levels of TBXs were quantified in NSCLC cells using real-time PCR and methylation-specific PCR assays, respectively. Effects of the DNA methyltransferase inhibitor 5-azacytidine (Aza) on TBX2 subfamily expression were assessed in NSCLC cells. Impact of TBX2 subfamily expression on Aza-treated cells was evaluated by RNA interference. (3) All four TBXs were significantly hypermethylated in NSCLCs relative to normal lung tissues (p < 0.05). Methylation β-values of the genes, with exception of TBX2, were significantly inversely correlated with corresponding mRNA expression levels (p < 0.05). We found no statistically significant differences in hypermethylation levels of the TBX2 subfamily by clinicopathological features including stage and tobacco history. Expression levels of the TBX genes were overall suppressed in NSCLC cells relative to normal alveolar cells. Members of the subfamily were significantly hypermethylated in all tested NSCLC cell lines relative to normal alveolar cells. Treatment with Aza induced the expression of the TBX2 subfamily concomitant with NSCLC cell growth inhibition. Further, simultaneous knockdown of the four TBX genes markedly reduced anti-growth effects of Aza in NSCLC cells. (4) Our study sheds light on new epigenetic profiles in the molecular pathogenesis of human NSCLC.

Neonatal Lung Disease Associated with TBX4 Mutations

Variable lung disease was documented in 2 infants with heterozygous TBX4 mutations; their clinical presentations, pathology, and outcomes were distinct. These findings demonstrate that TBX4 gene mutations are associated with neonatal respiratory failure and highlight the wide spectrum of clinicopathological outcomes that have implications for patient diagnosis and management.

Prognostic significance of high metabolic activity in breast cancer: PET signature in breast cancer

High metabolic activity, reflected in increased glucose uptake, is one of the hallmarks of many cancers including breast cancer. However, not all cancers avidly take up glucose, suggesting heterogeneity in their metabolic demand. Thus, we aim to generate a genomic signature of glucose hypermetabolism in breast cancer and examine its clinical relevance. To identify genes significantly associated with glucose uptake, gene expression data were analyzed together with the standardized uptake values (SUVmax) of ¹⁸F-fluorodeoxy-glucose on positron emission tomography (PET) for 11 breast cancers. The resulting PET signature was evaluated for prognostic significance in four large independent patient cohorts (n = 5417). Potential upstream regulators accountable for the high glucose uptake were identified by gene network analysis. A PET signature of 242 genes was significantly correlated with SUVmax in breast cancer. In all four cohorts, high PET signature was significantly associated with poorer prognosis. The prognostic value of this PET signature was further supported by Cox regression analyses (hazard ratio 1.7, confidential interval 1.48-2.02; P < 0.001). The PET signature was also strongly correlated with previously established prognostic genomic signatures such as PAM50, Oncotype DX, and NKI. Gene network analyses suggested that MYC and TBX2 were the most significant upstream transcription factors in the breast cancers with high glucose uptake. A PET signature reflecting high glucose uptake is a novel independent prognostic factor in breast cancer. MYC and TBX2 are potential regulators of glucose uptake.

Transcriptional repression of the ectodomain sheddase ADAM10 by TBX2 and potential implication for Alzheimer's disease

BACKGROUND

The ADAM10-mediated cleavage of transmembrane proteins regulates cellular processes such as proliferation or migration. Substrate cleavage by ADAM10 has also been implicated in pathological situations such as cancer or Morbus Alzheimer. Therefore, identifying endogenous molecules, which modulate the amount and consequently the activity of ADAM10, might contribute to a deeper understanding of the enzyme's role in both, physiology and pathology.

METHOD

To elucidate the underlying cellular mechanism of the TBX2-mediated repression of ADAM10 gene expression, we performed overexpression, RNAi-mediated knockdown and pharmacological inhibition studies in the human neuroblastoma cell line SH-SY5Y. Expression analysis was conducted by e.g. real-time RT-PCR or western blot techniques. To identify the binding region of TBX2 within the ADAM10 promoter, we used luciferase reporter assay on deletion constructs and EMSA/WEMSA experiments. In addition, we analyzed a TBX2 loss-of-function Drosophila model regarding the expression of ADAM10 orthologs by qPCR. Furthermore, we quantified the mRNA level of TBX2 in post-mortem brain tissue of AD patients.

RESULTS

Here, we report TBX2 as a transcriptional repressor of ADAM10 gene expression: both, the DNA-binding domain and the repression domain of TBX2 were necessary to effect transcriptional repression of ADAM10 in neuronal SH-SY5Y cells. This regulatory mechanism required HDAC1 as a co-factor of TBX2. Transcriptional repression was mediated by two functional TBX2 binding sites within the core promoter sequence (- 315 to - 286 bp). Analysis of a TBX2 loss-of-function Drosophila model revealed that kuzbanian and kuzbanian-like, orthologs of ADAM10, were derepressed compared to wild type. Vice versa, analysis of cortical brain samples of AD-patients, which showed reduced ADAM10 mRNA levels, revealed a 2.5-fold elevation of TBX2, while TBX3 and TBX21 levels were not affected.

CONCLUSION

Our results characterize TBX2 as a repressor of ADAM10 gene expression and suggest that this regulatory interaction is conserved across tissues and species.

A regulatory variant in TBX2 promoter is related to the decreased susceptibility of congenital heart disease in the Han Chinese population

Background

Tbx2 plays a vital role in the cardiac cushion development. In this study, we aimed to determine the relationship between common genetic variants in the promoter region of TBX2 gene and the risk of congenital heart disease (CHD).

Methods

Blood samples of 516 CHD patients and 587 control subjects were enrolled. Sanger sequencing and SNaPshot analysis were performed for genotyping in our case–control cohort. Luciferase and electrophoretic mobility shift assay (EMSA) were conducted to uncover the potential modulatory mechanism of the related variants.

Results

Variant rs4455026(c.‐1028G>C) in TBX2 promoter region was found to be associated with significantly lower CHD susceptibility. The risk of CHD in C allele carriers (GC and CC genotypes) decreased by 30% compared to the wild‐type GG genotype subjects (OR = 0.70, 95% CI = 0.55–0.89, p = 0.0038). It was revealed that G to C variation resulted in a decrease in the transcriptional activity of luciferase gene, and a potential change in binding affinity with certain nucleoproteins in EMSA data.

Conclusion

The minor C allele of rs4455026 in TBX2 promoter region was related with lower CHD susceptibility in the Han Chinese population via repressing its transcriptional activity.

TBX2 overexpression promotes proliferation and invasion through epithelial-mesenchymal transition and ERK signaling pathway

The present study aimed to clarify the clinical significance and biological effects of T-box (TBX)2 and its potential mechanism in gastric cancer (GC). TBX2 protein expression levels in human GC tissues were investigated using immunohistochemistry, and it was demonstrated that TBX2 was overexpressed in 55.9% (90/161) GC samples. TBX2 overexpression correlated with tumor invasion, advanced tumor node metastasis stage and presence of lymph node metastasis. In addition, TBX2 correlated with poor patient survival. To investigate the effect of TBX2 on biological behaviors, TBX2 plasmid transfection was performed in SGC-7901 cells and TBX2 small interfering RNA knockdown was carried out in BGC-823 cells. MTT and matrigel invasion assays demonstrated that TBX2 overexpression promoted proliferation and invasion, whereas TBX2 depletion inhibited proliferation and invasion. TBX2 overexpression also promoted epithelial-mesenchymal transition by downregulating E-cadherin and upregulating N-cadherin. TBX2 overexpression also upregulated matrix metalloproteinase (MMP)2, MMP9, cyclin E and phosphorylated-extracellular signal regulated kinase levels, however downregulated p21. In conclusion, TBX2 may serve as an effective predictor and therapeutic target in human GC.

Identification of TBX2 and TBX3 variants in patients with conotruncal heart defects by target sequencing

Background

Conotruncal heart defects (CTDs) are heterogeneous congenital heart malformations that result from outflow tract dysplasia; however, the genetic determinants underlying CTDs remain unclear. Increasing evidence demonstrates that dysfunctional TBX2 and TBX3 result in outflow tract malformations, implying that both of them are involved in CTD pathogenesis. We screened for TBX2 and TBX3 variants in a large cohort of CTD patients (n = 588) and population-matched healthy controls (n = 300) by target sequencing and genetically analyzed the expression and function of these variants.

Results

The probably damaging variants p.R608W, p.T249I, and p.R616Q of TBX2 and p.A192T, p.M65L, and p.A562V of TBX3 were identified in CTD patients, but none in controls. All altered amino acids were highly conserved evolutionarily. Moreover, our data suggested that mRNA and protein expressions of TBX2 and TBX3 variants were altered compared with those of the wild-type. We screened PEA3 and MEF2C as novel downstream genes of TBX2 and TBX3, respectively. Functional analysis revealed that TBX2R608W and TBX2R616Q variant proteins further activated HAS2 promoter but failed to activate PEA3 promoter and that TBX3A192T and TBX3A562V variant proteins showed a reduced transcriptional activity over MEF2C promoter.

Conclusions

Our results indicate that the R608W and R616Q variants of TBX2 as well as the A192T and A562V variants of TBX3 contribute to CTD etiology; this was the first association of variants of TBX2 and TBX3 to CTDs based on a large population.

Electronic supplementary material

The online version of this article (10.1186/s40246-018-0176-0) contains supplementary material, which is available to authorized users.

EGR1 interacts with TBX2 and functions as a tumor suppressor in rhabdomyosarcoma

EGR1, one of the immediate-early response genes, can function as a tumor suppressor gene or as an oncogene in cancer. The function of EGR1 has not been fully characterized in rhabdomyosarcoma (RMS), a pediatric cancer derived from the muscle linage. We found that EGR1 is downregulated in the alveolar RMS (ARMS) subtype but expressed at levels comparable to normal skeletal muscle in embryonal RMS (ERMS). We found that overexpression of EGR1 in ARMS significantly decreased cell proliferation, mobility, and anchorage-independent growth while also promoting differentiation. We found that EGR1 interacts with TBX2, which we have shown functions as an oncogene in RMS. The interaction inhibits EGR1 dependent gene expression, which includes the cell cycle regulators p21 and PTEN as well as other important cell growth drivers such as NDRG1 and CST6. We also found that EGR1 induced apoptosis by triggering the intrinsic apoptosis pathway. EGR1 also activated two pro-apoptotic factors, BAX and dephosphorylated BAD, which are both located upstream of the caspase cascades in the intrinsic pathway. EGR1 also sensitized RMS cells to chemotherapeutic agents, suggesting that activating EGR1 may improve therapeutic targeting by inducing apoptosis. Our results establish the important role of EGR1 in understanding RMS pathology.

TBX2 over-expression promotes nasopharyngeal cancer cell proliferation and invasion

TBX2 is a member of the T box transcription factor family. Its expression and potential biological functions in nasopharyngeal cancer (NPC) cells are studied here. We showed that TBX2 mRNA and protein expression was significantly elevated in multiple human NPC tissues, as compared with that in adjacent normal tissues. Knockdown of TBX2 by targeted-siRNA significantly inhibited proliferation and invasion of NPC cells (CNE-1 and HONE-1 lines). Meanwhile, TBX2 knockdown also induced G1-phase cell cycle arrest. At the molecular level, we discovered that expressions of several tumor suppressor genes, including p21, p27, phosphatase with tensin homology (PTEN) and E-Cadherin, were increased dramatically after TBX2 knockdown in above NPC cells. Collectively, our results imply that TBX2 over-expression promotes NPC cell proliferation and invasion, possibly via silencing several key tumor suppressor genes.

Association of TBX2 and P21 expression with clinicopathological features and survival of laryngeal squamous cell carcinoma

BACKGROUND

The expression of P21 and TBX2 in laryngeal squamous cell carcinoma (LSCC) and their corresponding adjacent normal laryngeal tissues, as well as their association with clinical pathological features and survival remain unclear.

METHOD

we used the RT-PCR and immunohistochemistry to detect their mRNA and protein levels in 75 LSCC patients. We also use log-rank test and Cox models to compare survival among different groups.

RESULTS

The mRNA expression level of TBX2 was up-regulated, while P21 was down-regulated in LSCC compared with their matched adjacent laryngeal tissues (All P < 0.001). The expression of P21 was correlated with tumor stage, lymph node metastasis and smoking; and TBX2 expression was associated with lymph node metastasis, differentiation degree and smoking (All P < 0.05). Patients with high TBX2 and low P21 expression had significantly worse survival than those with low TBX2 and high P21 expression, respectively (All P < 0.05). A significant correlation between expression of TBX2 and P21 (Pearson, P < 0.05) was observed. Furthermore, multivariable analysis showed that patients with low TBX2 and high P21 expression alone had a significantly reduced risk for overall death compared with those with low TBX2 and high P21 expression. The risk for overall death was even lower for patients with both low and high expression of both genes than any other co-expression status of both genes (HR, 0.1; 95% CI, 0.0-0.9).

CONCLUSION

These results suggest that abnormal expression of P21 and TBX2 in tumors may jointly, or individually, predict poor prognosis of LSCC.

The anti-proliferative function of the TGF-β1 signaling pathway involves the repression of the oncogenic TBX2 by its homologue TBX3

A growing body of work has shown that the highly homologous T-box transcription factors TBX2 and TBX3 play critical but distinct roles in embryonic development and cancer progression. For example, TBX2 and TBX3 are up-regulated in several cancers and recent evidence suggests that whereas TBX2 functions as a pro-proliferative factor, TBX3 inhibits cell proliferation but promotes cancer cell migration and invasion. While the molecular mechanisms regulating these functions of TBX2 and TBX3 are poorly understood we recently reported that the TGF-β1 signaling pathway up-regulates TBX3 expression to mediate, in part, its well described anti-proliferative and pro-migratory roles. The TBX3 targets responsible for these functions were however not identified. Here we reveal for the first time that the TGF-β1 signaling pathway represses TBX2 transcriptionally and we provide a detailed mechanism to show that this is mediated by TBX3. Furthermore, we implicate the down-regulation of TBX2 in the anti-proliferative function of the TGF-β1-TBX3 axis. These findings have important implications for our understanding of the regulation of TBX2 and TBX3 and shed light on the mechanisms involved in the anti-proliferative and pro-migratory roles of TGF-β1.

T-box transcription factors in cancer biology

The evolutionarily conserved T-box family of transcription factors have critical and well-established roles in embryonic development. More recently, T-box factors have also gained increasing prominence in the field of cancer biology where a wide range of cancers exhibit deregulated expression of T-box factors that possess tumour suppressor and/or tumour promoter functions. Of these the best characterised is TBX2, whose expression is upregulated in cancers including breast, pancreatic, ovarian, liver, endometrial adenocarcinoma, glioblastomas, gastric, uterine cervical and melanoma. Understanding the role and regulation of TBX2, as well as other T-box factors, in contributing directly to tumour progression, and especially in suppression of senescence and control of invasiveness suggests that targeting TBX2 expression or function alone or in combination with currently available chemotherapeutic agents may represent a therapeutic strategy for cancer.

TBX2 blocks myogenesis and promotes proliferation in rhabdomyosarcoma cells

Rhabdomyosarcomas (RMSs) are the most frequent soft tissue sarcomas in children that share many features of developing skeletal muscle. We have discovered that a T-box family member, TBX2, is highly upregulated in tumor cells of both major RMS subtypes. TBX2 is a repressor that is often overexpressed in cancer cells and is thought to function in bypassing cell growth control, including repression of p14 and p21. The cell cycle regulator p21 is required for the terminal differentiation of skeletal muscle cells and is silenced in RMS cells. We have found that TBX2 interacts with the myogenic regulatory factors MyoD and myogenin and inhibits the activity of these factors. TBX2 is expressed in primary myoblasts and C2C12 cells, but is strongly downregulated upon differentiation. TBX2 recruits the histone deacetylase HDAC1 and is a potent inhibitor of the expression of muscle-specific genes and the cell cycle regulators, p21 and p14. TBX2 promotes the proliferation of RMS cells and either depletions of TBX2 or dominant negative TBX2 upregulate p21- and muscle-specific genes. Significantly, depletion or interference with TBX2 completely inhibits tumor growth in a xenograft assay, highlighting the oncogenic role of TBX2 in RMS cells. Thus, the data demonstrate that elevated expression of TBX2 contributes to the pathology of RMS cells by promoting proliferation and repressing differentiation-specific gene expression. These results show that deregulated TBX2 serves as an oncogene in RMS, suggesting that TBX2 may serve as a new diagnostic marker or therapeutic target for RMS tumors.

Novel and functional sequence variants within the TBX2 gene promoter in ventricular septal defects

Congenital heart disease (CHD) is the most common birth defects in humans. To date, genetic causes for CHD remain largely unknown. T-box transcription factor 2 (TBX2) gene is expressed in the myocardium of atrioventricular canal, outflow tract and inflow tract and plays a critical role in heart chamber formation. Genomic deletion and duplication of TBX2 gene have been associated with cardiac defects. As TBX2 acts in a dose-dependent manner, we hypothesized that DNA sequence variants (DSVs) within TBX2 gene promoter may mediate CHD development by changing TBX2 levels. In this study, TBX2 gene promoter was genetically analyzed in large cohorts of patients with ventricular septal defect (VSD) (n = 324) and ethnic-matched healthy controls (n = 328). Four novel and heterozygous DSVs, g.59477201C > T, g.59477347G > A, g.59477353delG and g.59477371G > A were identified in VSD patients, but in none of controls. Functional analyses revealed that all of the four DSVs significantly decreased transcriptional activities of TBX2 gene promoter. Therefore, our data suggested that the DSVs within TBX2 gene promoter identified in VSD patients may contribute to VSD etiology.

Mouse Lymphoblastic Leukemias Induced by Aberrant Prdm14 Expression Demonstrate Widespread Copy Number Alterations Also Found in Human ALL

Aberrant expression and activation of oncogenes in somatic cells has been associated with cancer initiation. Required for reacquisition of pluripotency in the developing germ cell, PRDM14 initiates lymphoblastic leukemia when misexpressed in murine bone marrow. Activation of pluripotency in somatic cells can lead to aneuploidy and copy number alterations during iPS cell generation, and we hypothesized that PRDM14-induced lymphoblastic leukemias would demonstrate significant chromosomal damage. High-resolution oligo array comparative genomic hybridization demonstrated infrequent aneuploidy but frequent amplification and deletion, with amplifications occurring in a 5:1 ratio with deletions. Many deletions (i.e., Cdkn2a, Ebf1, Pax5, Ikzf1) involved B-cell development genes and tumor suppressor genes, recapitulating deletions occurring in human leukemia. Pathways opposing senescence were frequently deactivated via Cdkn2a deletion or Tbx2 amplification, with corollary gene expression. Additionally, gene expression studies of abnormal pre-leukemic B-precursors showed downregulation of genes involved in chromosomal stability (i.e., Xrcc6) and failure to upregulate DNA repair pathways. We propose a model of leukemogenesis, triggered by pluripotency genes like Prdm14, which involves ongoing DNA damage and failure to activate non-homologous end-joining secondary to aberrant gene expression.

The Highly Homologous T-Box Transcription Factors, TBX2 and TBX3, Have Distinct Roles in the Oncogenic Process

The T-box transcription factors TBX2 and TBX3 are overexpressed in several cancers and are able to bypass senescence by repressing ARF and p21(WAF1/CIP1/SDII). Although these studies suggest that they may both contribute to the oncogenic process by repressing common targets, whether they have redundant or distinct roles in cancers where they are both overexpressed remains to be elucidated. Importantly, when Tbx2 function is inhibited in melanoma cells lacking Tbx3, the cells senesce, but whether this is possible in melanoma cells overexpressing both proteins is not known. An understanding of this issue may have important implications for the design of an effective pro-senescence therapy. In this study, the authors used a sh-RNA approach to knock down TBX2 and TBX3 individually in 2 human melanoma cell lines that overexpress both these factors and then examined their specific involvement in the oncogenic process. They demonstrate, using in vitro and in vivo cell proliferation, as well as colony- and tumor-forming ability and cell motility assays, that TBX2 and TBX3 have distinct roles in melanoma progression. In the tested lines, although TBX2 could promote proliferation and transformation and was required by primary melanoma cells for immortality, TBX3 was required for tumor formation and cell migration. These findings were reproducible in a human breast cancer cell line, which confirms that TBX2 and TBX3, although highly homologous, do not have redundant roles in the transformation process of cancers where they are both overexpressed. These results have important implications for the development of new cancer treatments and in particular for melanoma, which is a highly aggressive and intractable cancer.