Tbx3 overexpression in human gastric cancer is correlated with advanced tumor stage and nodal status and promotes cancer cell growth and invasion

Abnormal activation of the Wnt3a/β-catenin signaling pathway promotes the expression of T-box transcription factor 3(TBX3) and the epithelial-mesenchymal transition pathway to mediate the occurrence of adenomyosis

BACKGROUND

T-box transcription factor 3(TBX3) is a transcription factor that can regulate cell proliferation, apoptosis, invasion, and migration in different tumor cells; however, its role in adenomyosis (ADM) has not been previously studied. Some of ADM's pathophysiological characteristics are similar to those of malignant tumors (e.g., abnormal proliferation, migration, and invasion).

METHODS AND RESULTS

We hypothesized that TBX3 might have a role in ADM. We used tamoxifen-induced Institute of Cancer research (ICR) mice to establish ADM disease model. The study procedure included western blotting and immunohistochemistry to analyze protein levels; additionally, we used intraperitoneal injection of Wnt/β-catenin pathway inhibitor XAV-939 to study the relationship between TBX3 and Wnt/β-catenin pathway as well as Anti-proliferation cell nuclear antigen( PCNA) and TUNEL to detect cell proliferation and apoptosis, respectively. TBX3 overexpression and epithelial-to-mesenchymal transition (EMT) in ADM mice was found to be associated with activation of the Wnt3a/β-catenin pathway. Treatment with XAV-939 in ADM mice led to the inhibition of both TBX3 and EMT; moreover, abnormal cell proliferation was suppressed, the depth of invasion of endometrium cells was limited. Thus, the use of XAV-939 effectively inhibited further invasion of endometrial cells.

CONCLUSION

These findings suggest that TBX3 may play an important role in the development of ADM. The expression of TBX3 in ADM was regulated by the Wnt3a/β-catenin pathway. The activation of the Wnt3a/β-catenin pathway in ADM promoted TBX3 expression and induced the occurrence of EMT, thus promoting cell proliferation and inhibiting apoptosis, ultimately accelerating the development of ADM. The study provides a reference for the diagnosis of ADM.

Role of T-box transcription factor 3 in gastric cancers

The expression of T-box transcription factor 3 (TBX3) has been identified in various cancers, including gastric cancers. Its role in breast cancers and melanomas has been intensively studied, and its contribution to the progression of cancers through suppressing senescence and promoting epithelial-mesenchymal transition has been reported. Recent reports on the role of TBX3 in gastric cancers have implied its involvement in gastric carcinogenesis. Considering its pivotal role in the initiation and progression of cancers, TBX3 could be a promising therapeutic target for gastric cancers.

Wnt Signaling and Aging of the Gastrointestinal Tract

Aging is considered a risk factor for various diseases including cancers. In this aging society, there is an urgent need to clarify the molecular mechanisms involved in aging. Wnt signaling has been shown to play a crucial role in the maintenance and differentiation of tissue stem cells, and intensive studies have elucidated its pivotal role in the aging of neural and muscle stem cells. However, until recently, such studies on the gastrointestinal tract have been limited. In this review, we discuss recent advances in the study of the role of Wnt signaling in the aging of the gastrointestinal tract and aging-related carcinogenesis.

Suppressed Cellular Senescence Mediated by T-box3 in Aged Gastric Epithelial Cells may Contribute to Aging-related Carcinogenesis

Aging is a risk factor for cancers in various organs. Recent advances in the organoid culturing system have made it viable to investigate the influence of aging utilizing these mini organs. In this study, we aimed to examine the implications of aging for gastric carcinogenesis. Gastric organoids established from aged mice grew larger, proliferated vigorously, and survived longer than that from young mice. Because Wnt/β-catenin signaling was intensified in the aged organoids and because removal of Wnt-related factors diminished their proliferation, we investigated for Wnt target gene that contributed to enhanced proliferation and discovered that the aged organoids expressed the transcription factor T-box3 (Tbx3), which has been reported to suppress cellular senescence. Indeed, cellular senescence was suppressed in the aged organoids, and this resulted from enhanced G₂-M transition. As for the mechanism involved in the intensified Wnt/β-catenin signaling, we identified that Dickkopf3 (Dkk3) expression was reduced in the aged organoids due to methylation of the Dkk3 gene. Finally, the expression of TBX3 was enhanced in human atrophic gastritis and even more enhanced in human gastric cancers. In addition, its expression correlated positively with patients' age. These results indicated that the emergence of antisenescent property in aged gastric organoids due to enhanced Tbx3 expression led to accelerated cellular proliferation and organoid formation. Because the enhanced Tbx3 expression seen in aged gastric organoids was also observed in human gastric cancer tissues, this Dkk3-Wnt-Tbx3 pathway may be involved in aging-related gastric carcinogenesis.

Significance

This work provides an insight into the mechanism involved in aging-related gastric carcinogenesis through studies utilizing organoids established from young and aged murine stomachs.

A Single-Center Follow-Up Study of Low-Grade Gastric Intraepithelial Neoplasia and the Screening of Key Genes of Precancerous Lesions

Objective

The study aimed to summarize the morphological characteristics of low-grade gastric intraepithelial neoplasia (LGIN) and explore its outcomes and risk factors. Additionally, it aimed to screen the core different expression genes (DEGs) of high-grade gastric intraepithelial neoplasia (HGIN) using bioinformatics methods to identify biomarkers for early gastric cancer outcomes.

Methods

The clinical and pathological data of 449 patients with LGIN in the endoscopy center of the Second Hospital of Hebei Medical University from June 2013 to September 2018 were collected for retrospective analysis. The GSE130823 and GSE55696 data sets were selected from the Gene Expression Omnibus database, and the GEO2R tool was used to screen DEGs in HGIN and chronic gastritis tissue types. A DEG functional enrichment analysis was conducted using the Database for Annotation, Visualization, and Integrated Discovery. The STRING database was utilized to create a protein–protein interaction network, and the CytoHubba plug-in was used to screen the key genes of HGIN.

Results

The incidence of LGIN increased with age, and most of the patients were aged between 45–59 years (P = 0.048). Lesions were found mainly in the cardia, mostly in people aged 60 (P < 0.05). Progression occurred in 42 of 449 patients, with a 9.4% rate of cancer development. Foci larger than 10 mm, ulcerative lesions, and an Helicobacter pylori-positive result were factors affecting the outcome of LGIN (P < 0.05). Seven core genes of HGIN were screened, including MYC, SOX2, CDX2, TBX3, KRT7, CDKN2A, and MUC5AC.

Conclusion

The patients with LGIN reflected the potential for developing cancer. A magnifying gastroscope can contribute to the detection of early gastric cancer. Additionally, the MYC, CDX2, and TBX3 genes may act as specific biomarkers of HGIN.

Role of T-box genes in cancer, epithelial-mesenchymal transition, and cancer stem cells

Sharing a common DNA binding motif called T-box, transcription factor T-box gene family controls embryonic development and is also involved in cancer progression and metastasis. Cancer metastasis shows therapy resistance and involves complex processes. Among them, epithelial-mesenchymal transition (EMT) triggers cancer cell invasiveness and the acquisition of stemness of cancer cells, called cancer stem cells (CSCs). CSCs are a small fraction of tumor bulk and are capable of self-renewal and tumorsphere formation. Recent progress has highlighted the critical roles of T-box genes in cancer progression, EMT, and CSC function, and such regulatory functions of T-box genes have emerged as potential therapeutic candidates for cancer. Herein we summarize the current understanding of the regulatory mechanisms of T-box genes in cancer, EMT, and CSCs, and discuss the implications of targeting T-box genes as anticancer therapeutics.

RNA cargos in extracellular vesicles derived from blood serum in pancreas associated conditions

Exosomes are extracellular vesicles which are released from healthy and tumor cells into blood circulation. Unique biomolecular cargos such as RNA and protein are loaded in these vesicles. These molecules may have biological functions such as signaling, cell communications and have the potential to be analyzed as biomarkers. In this initial study, we describe the analysis of exosomes in the serum of healthy subjects, intraductal papillary mucosal neoplasms and pancreatic ductal adenocarcinoma including the characterization of their RNA cargos by next generation sequencing (EXO-NGS). Results indicate the presence of a wide variety of RNAs including mRNA, miRNA, lincRNA, tRNA and piRNA in these vesicles. Based on the differential mRNA expression observed upon EXO-NGS analysis, we independently evaluated two protein coding genes, matrix metalloproteinase-8 (MMP-8) and transcription factor T-Box 3 (TBX3) by qRT-PCR for selective expression in the serum samples. Results indicate a variable expression pattern of these genes across serum samples between different study groups. Further, qRT-PCR analysis with the same serum exosomes processed for EXO-NGS, we observed two long non-coding RNAs, malat-1 and CRNDE to be variably expressed. Overall, our observations emphasize the potential value of different exosome components in distinguishing between healthy, premalignant and malignant conditions related to the pancreas.

The roles and regulation of TBX3 in development and disease

TBX3, a member of the ancient and evolutionary conserved T-box transcription factor family, is a critical developmental regulator of several structures including the heart, mammary glands, limbs and lungs. Indeed, mutations in the human TBX3 lead to ulnar mammary syndrome which is characterized by several clinical malformations including hypoplasia of the mammary and apocrine glands, defects of the upper limb, areola, dental structures, heart and genitalia. In contrast, TBX3 has no known function in adult tissues but is frequently overexpressed in a wide range of epithelial and mesenchymal derived cancers. This overexpression greatly impacts several hallmarks of cancer including bypass of senescence, apoptosis and anoikis, promotion of proliferation, tumour formation, angiogenesis, invasion and metastatic capabilities as well as cancer stem cell expansion. The debilitating consequences of having too little or too much TBX3 suggest that its expression levels need to be tightly regulated. While we have a reasonable understanding of the mutations that result in low levels of functional TBX3 during development, very little is known about the factors responsible for the overexpression of TBX3 in cancer. Furthermore, given the plethora of oncogenic processes that TBX3 impacts, it must be regulating several target genes but to date only a few have been identified and characterised. Interestingly, while there is compelling evidence to support oncogenic roles for TBX3, a few studies have indicated that it may also have tumour suppressor functions in certain contexts. Together, the diverse functional elasticity of TBX3 in development and cancer is thought to involve, in part, the protein partners that it interacts with and this area of research has recently received some attention. This review provides an insight into the significance of TBX3 in development and cancer and identifies research gaps that need to be explored to shed more light on this transcription factor.

Isoform-specific promotion of breast cancer tumorigenicity by TBX3 involves induction of angiogenesis

TBX3 is a member of the highly conserved family of T-box transcription factors involved in embryogenesis, organogenesis and tumor progression. While the functional role of TBX3 in tumorigenesis has been widely studied, less is known about the specific functions of the different isoforms (TBX3iso1 and TBX3iso2) which differ in their DNA-binding domain. We therefore sought to investigate the functional consequence of this highly conserved splice event as it relates to TBX3-induced tumorigenesis. By utilizing a nude mouse xenograft model, we have identified differential tumorigenic potential between TBX3 isoforms, with TBX3iso1 overexpression more commonly associated with invasive carcinoma and high tumor vascularity. Transcriptional analysis of signaling pathways altered by TBX3iso1 and TBX3iso2 overexpression revealed significant differences in angiogenesis-related genes. Importantly, osteopontin (OPN), a cancer-associated secreted phosphoprotein, was significantly up-regulated with TBX3iso1 (but not TBX3iso2) overexpression. This pattern was observed across three non/weakly-tumorigenic breast cancer cell lines (21PT, 21NT, and MCF7). Up-regulation of OPN in TBX3iso1 overexpressing cells was associated with induction of hyaluronan synthase 2 (HAS2) expression and increased retention of hyaluronan in pericellular matrices. These transcriptional changes were accompanied by the ability to induce endothelial cell vascular channel formation by conditioned media in vitro, which could be inhibited through addition of an OPN neutralizing antibody. Within the TCGA breast cancer cohort, we identified an 8.1-fold higher TBX3iso1 to TBX3iso2 transcript ratio in tumors relative to control, and this ratio was positively associated with high-tumor grade and an aggressive molecular subtype. Collectively, the described changes involving TBX3iso1-dependent promotion of angiogenesis may thus serve as an adaptive mechanism within breast cancer cells, potentially explaining differences in tumor formation rates between TBX3 isoforms in vivo. This study is the first of its kind to report significant functional differences between the two TBX3 isoforms, both in vitro and in vivo.

TBX3 knockdown suppresses the proliferation of hypopharyngeal carcinoma FaDu cells by inducing G1/S cell cycle arrest and apoptosis

The T-box transcription factor family member TBX3 has been demonstrated to participate in the development of various types of cancer, including head and neck squamous cell carcinoma. However, little is currently known about its role in hypopharyngeal carcinoma. In the present study, the involvement of TBX3 in hypopharyngeal carcinoma was investigated. Immunohistochemical assays revealed that TBX3 levels were increased in hypopharyngeal carcinoma compared with normal tissue samples, accompanied by upregulated N-cadherin and downregulated E-cadherin. Lentivirus-mediated TBX3 knockdown efficiently suppressed its expression and inhibited the proliferation of FaDu cells. The opposite was observed in TBX3-overexpressing FaDu cells. These results indicate that TBX3 is essential for FaDu cell proliferation. Furthermore, TBX3 silencing led to a disturbance of the cell cycle, leading to a decrease in the G₁ phase and an increase in the S phase. In addition, apoptosis was enhanced following TBX3 knockdown. The present results suggest TBX3 as a potential therapeutic target in hypopharyngeal carcinoma.

TBX3 deficiency accelerates apoptosis in cardiomyoblasts through regulation of P21 expression

Congenital heart disease (CHD) is the most common birth defect in newborns. There is increasing evidence that apoptosis and remodeling of the cardiomyoblasts are the major pathology of CHD. Previous research found that T-box transcription factor 3 (TBX3) was compulsory for the regulation of proliferation, cell cycle arrest and apoptosis in various cells. Hence, TBX3 might be involved in the treatment of CHD. The primary aim of this study was to study the effects of TBX3 on apoptosis in aged cardiomyoblasts and investigate the latent mechanism. In the present study, we found TBX3 knockdown induced proliferation inhibition, cell cycle arrest and apoptosis accompanied by mitochondrial dysfunction in cardiomyoblasts at passage 10 to 15. Apoptosis-inducing effects of TBX3 silence could be neutralized by silencing P21 using specific siRNA. In addition, the mRNA and protein expression levels of TBX3 in the heart tissues of sporadic type CHD donors were obviously down-regulated. In conclusion, we demonstrated that TBX3 deficiency accelerated apoptosis via directly regulating P21 expression in senescent cardiomyoblasts.

The special stemness functions of Tbx3 in stem cells and cancer development

The T-box factors belong to an ancient protein family, which comprises a cluster of evolutionarily-conserved transcription factors that regulate gene expression and that are crucial to embryonic development. T-box transcription factor 3 (Tbx3) is a member of this family, is expressed in some tissues, and is a key regulator in many critical organs, including the heart, mammary gland, and limbs. Overexpression of Tbx3 is associated with a number of cancers, including head and neck squamous cell carcinoma, gastric, breast, ovary, cervical, pancreatic, bladder and liver cancers, as well as melanoma. Tbx3 promotes tumor development by modulating cell proliferation, tumor formation, metastasis, cell survival and drug resistance. Moreover, there is strong evidence that Tbx3 regulates stem cell maintenance by controlling stem cell self-renewal and differentiation. Verification of the upstream regulatory factors and potential molecular mechanism of Tbx3, being able to explain the function of Tbx3 in carcinogenic effects and stem cell maintenance, will make a valuable contribution to stem cell and cancer research. This review provides an insight into the current research on Tbx3 and explores the significance of Tbx3 in stem cells and tumorigenesis.

Novel HDAC5-interacting motifs of Tbx3 are essential for the suppression of E-cadherin expression and for the promotion of metastasis in hepatocellular carcinoma

Tbx3, a transcriptional repressor, is essential in the organogenesis of vertebrates, stem cell self-renewal and differentiation, and the carcinogenesis of multiple tumor types. However, the mechanism by which Tbx3 participates in the metastasis of hepatocellular carcinoma (HCC) remains largely unknown. In this study, we show that Tbx3 was dramatically upregulated in clinical HCC samples and that elevated expression of Tbx3 promoted cancer progression. To determine the underlying mechanism, systematic glycine scan mutagenesis and deletion assays were performed. We identified two critical motifs, ⁵⁸⁵LFSYPYT⁵⁹¹ and ⁶⁰⁴HRH⁶⁰⁶, that contribute to the repression of transcriptional activity. These motifs are also essential for Tbx3 to promote cell migration and metastasis both in vitro and in vivo via the suppression of E-cadherin expression. More importantly, Tbx3 directly interacts with HDAC5 via these motifs, and an HDAC inhibitor blocks Tbx3-mediated cell migration and the downregulation of E-cadherin in HCC. As Tbx3 is involved in the carcinogenesis of multiple types of human cancers, our findings suggest an important target for anti-cancer drug development.

A regulatory protein that represses gene activity interacts with an enzyme involved in chromosome remodeling to promote the migration and metastasis of liver cancer cells. Ming-Liang He from the City University of Hong Kong and colleagues found that levels of the T-box transcription factor Tbx3 were dramatically increased in tissue biopsies of liver tumors. They injected Tbx3-expressing human liver cancer cells into mice and saw a positive correlation between Tbx3 activity and cancer progression. By mutating and deleting parts of Tbx3, the researchers identified two particular stretches of the protein that bind histone deacetylase 5, an enzyme involved in ensuring DNA coils, are wound tight to suppress gene activity. This interaction is needed for Tbx3’s tumor-promoting function and may be targetable with drugs in order to prevent metastasis in patients with aggressive liver cancer.

T-box Transcription Factor Tbx3 Contributes to Human Hepatocellular Carcinoma Cell Migration and Invasion by Repressing E-Cadherin Expression

Tbx3, a member of the T-box family of transcription factors, contributes directly to tumor formation, migration, and invasion. However, the role of Tbx3 in the metastasis of HCC remains unclear. In the present study, Tbx3 expression was detected in HCC tissues and cells by Western blot, and Tbx3 expression was regulated by use of siRNAs or lentivirus-mediated vectors. Here we found that Tbx3 protein expression increased in HCC tissues and cell lines. Tbx3 expression was positively associated with multiple tumor nodes, venous infiltration, and advanced TNM tumor stage. Survival analysis demonstrated that Tbx3 expression was an independent prognostic factor for HCC patients. In vitro assays further validated that Tbx3 indeed prompted HCC cell migration and invasion. In addition, Tbx3 expression was negatively related with E-cadherin expression in HCC tissues. Mechanically, Tbx3 inhibited the expression of E-cadherin, and then facilitated epithelial-mesenchymal transition (EMT) of HCC cells. Furthermore, the effect of Tbx3 knockdown on HCC cells was attenuated by E-cadherin knockdown. In conclusion, Tbx3 may be a novel prognostic factor, and it contributes to HCC cell migration, invasion, and EMT by repressing E-cadherin expression. Thus, Tbx3 may be recommended as a therapeutic target for HCC patients.