B-cell Translocation Gene 2 Expression Research Articles

Delineating the mechanistic relevance of the TP53 gene and its mutational impact on gene expression and patients’ survival in bladder cancer

Bladder carcinoma (BLCA) is a widespread urological malignancy causing significant global mortality, often hindered by delayed diagnosis and limited treatments. BLCA frequently exhibits TP53 mutations, playing a pivotal role in its pathogenesis and underscoring the potential of targeting TP53 as a therapeutic approach for this prevalent urological malignancy. Tumor tissues from 50 bladder cancer patients were used for mutational analysis in TP53's mutation-rich exons (5, 7, & 8). The gene expression of the TP53 gene, along with a TP53-target gene B‐cell translocation gene 2 (BTG2) was also assessed in the cDNA samples from the same BLCA tissues and 15 urine controls of healthy people. The analysis revealed 22 % of patients with somatic hotspot mutations, 18 % with pathogenic missense mutations, and 12 % with intronic variants. Patients with somatic mutations exhibited the worst prognosis, supported by survival analysis from The Cancer Genome Atlas (TCGA) BLCA data. Interestingly, H296Y missense mutation correlated with higher TP53 expression and improved survival, while intronic SNPs were linked to worse outcomes. Additionally, upregulated BTG2 expression in mutated patients was observed which was correlated with poor prognosis, emphasizing the role of TP53 mutations in bladder cancer progression. The multivariate analysis highlighted the predictive power of TP53 mutations, with a high frequency of high-grade tumors (78.57 %) in mutated patients, underscoring their role in cancer progression. In conclusion, this study emphasizes the crucial role of TP53 mutations in bladder cancer patients from Bangladesh.

MicroRNA-322-5p protects against myocardial infarction through targeting BTG2

BackgroundNumerous studies have explored the therapeutic potential of microRNA (miR) in myocardial infarction (MI) treatment. This study focuses on the role of miR-322-5p in MI, particularly in its regulatory interaction with B-cell translocation gene 2 (BTG2). Materials and methodsExpression levels of miR-322-5p and BTG2 were assessed in a rat MI model. Adenovirus altering miR-322-5p or BTG2 expression were administered to MI rats. Evaluation included cardiac function, inflammation, myocardial injury, pathological changes, apoptosis, and NF-κB pathway-related genes in MI rats post-targeted treatment. The miR-322-5p and BTG2 targeting relationship was investigated. ResultsMI rats exhibited low miR-322-5p and high BTG2 expression in the myocardial tissues. Restoration of miR-322-5p enhanced cardiac function, alleviated inflammation and myocardial injury, mitigated pathological changes and apoptosis, and deactivated the NF-κB pathway in MI rats. BTG2 expression was negatively-regulated by miR-322-5p. Overexpressed BTG2 counteracted miR-322-5p-induced cardioprotection on MI rats. ConclusionThis study provides evidence that miR-322-5p protects against MI by suppressing BTG2 expression.

BTG2 suppresses the growth and metastasis of cervical squamous cell carcinoma

BackgroundCervical cancer is the fourth most common malignancy in women, of which cervical squamous cell carcinoma (CESC) is the main pathological type of cervical cancer. B-cell translocation gene 2 (BTG2) protein has been recognized as a tumor suppressor in several cancer types. However, BTG2 expression and molecular function in CESC are unknown. MethodsIn this study, we first assessed the expression of BTG2 in tumor tissue specimens from CESC patients using immunohistochemical staining and real-time quantitative PCR, and explored the relationship between BTG2 expression status and clinical manifestations. Next, we constructed BTG2 knockdown and overexpression CESC cell lines to observe the effects of BTG2 on CESC proliferation and metastasis at the cellular level. Finally, we employed a nude mouse xenograft tumor model in an in vivo experiment to observe the effect of BTG2 on tumorigenesis in vivo. ResultsThe results showed that the expression of BTG2 protein was lower in CESC tissues than in normal tissues, and high BTG2 expression was associated with better survival in CESC patients versus CESC patients. The results of cellular assays confirm that overexpression of BTG2 inhibits the proliferation, migration and metastasis of CESC cells. Nude mouse xenograft tumor model showed that overexpression of BTG2 inhibited tumor growth in vivo, and conversely knockdown of BTG2 promoted tumor growth. ConclusionIn summary, our data suggest that BTG2 acts as a tumor suppressor in CESC and inhibits the growth and metastasis of CESC. BTG2 may serve as a potential prognostic marker in CESC and is expected to provide a therapeutic strategy for patients with CESC.

B-Cell Translocation Gene 2 Upregulation Is Associated with Favorable Prognosis in Lung Adenocarcinoma and Prolonged Patient Survival.

The tumor suppressor protein B-cell translocation gene 2 (BTG2) is downexpressed in lung adenocarcinoma (LUAD); however, its role in LUAD survival remains unknown. This investigation is aimed at exploring the activity of BTG2 in LUAD. We analyzed BTG2 expression in LUAD datasets of the TCGA database and examined that BTG2 was markedly downregulated in comparison with adjacent normal tissues. The prognostic analysis suggested that higher expression of BTG2 protein correlates with prolonged survival in patients. Vectors expressing BTG2 were stably transduced into lung adenocarcinoma A549 cells. The overexpression of BTG2 in A549 cells causes cellular G1 phase arrest but did not affect cell proliferation, accompanied by increased activation of NF-κB. Our data indicate that BTG2 overexpression may trigger an autoregulatory prosurvival NF-κB pathway, which is resistant to environmental intervention owing to an increased level of BTG2.

Elevated BTG2 improves the radiosensitivity of non-small cell lung cancer (NSCLC) through apoptosis.

BackgroundTo identify radio‐responsive genes and explore the biological function of encoded proteins in non‐small cell lung cancer (NSCLC).MethodsRadio‐responsive genes in irradiated H460 cells were screened from microarray data deposited in the Gene Expression Omnibus (GEO) database. A quantitative real time polymerase chain reaction assay was used to detect the expression of candidate radio‐responsive genes in irradiated cells. CCK‐8 assay, EDU assay, clone formation assay, immunofluorescence and flow cytometry were conducted to evaluate the biological function of B cell translocation gene 2 (BTG2) in NSCLC.ResultsBioinformatic analysis using GES20549 showed that BTG2 was a radio‐responsive gene in irradiated H460 cells. The mRNA expression level of BTG2 was lower in H460 cells compared with that in BEAS‐2B normal lung epithelial cells. BTG2 expression was elevated upon IR exposure, in a dose‐dependent but not a time‐dependent manner. CCK‐8 and EDU assays revealed that BTG2 overexpression inhibited the growth rate of irradiated cells. Clone formation showed that elevated BTG2 promoted DNA damage of irradiated H460 cells. The number of γ‐H2AX foci induced by DNA damage was also markedly increased upon BTG2 overexpression. Flow cytometry showed that BTG2 increased IR‐induced cell apoptosis.ConclusionsBTG2 may be a novel radio‐responsive factor and a promising therapeutic target for radiotherapy of NSCLC.

Urinary Exosomal miRNAs as biomarkers of bladder Cancer and experimental verification of mechanism of miR-93-5p in bladder Cancer

BackgroundBladder cancer (BC) is one of the most common malignancies globally. Early diagnosis of it can significantly improve patients’ survival and quality of life. Urinary exosomes (UEs)-derived miRNAs might be a promising biomarker for BC detection.MethodA total of 12 patients with BC and 4 non-cancerous participants (as healthy control) were recruited from a single center between March 2018 and December 2019 as the discovery set. Midstream urine samples from each participants were collected and high-throughput sequencing and differentially expression analysis were conducted. Combined with miRNA expression profile of BC tissue from The Cancer Genome Atlas (TCGA), miRNAs biomarkers for BC were determined. Candidate miRNAs as biomarkers were selected followed by verification with a quantitative reverse-transcription polymerase chain reaction assay in an independent validation cohort consisting of 53 BC patients and 51 healthy controls. The receiver-operating characteristic (ROC) curve was established to evaluate the diagnostic performance of UE-derived miRNAs. The possible mechanism of miRNAs were revealed by bioinformatic analysis and explored in vitro experiments.ResultsWe identified that miR-93-5p, miR-516a-5p were simultaneously significantly increased both in UEs from BC compared with healthy control and BC tissue compared with normal tissue, which were verified by RT-qPCR in the validation cohort. Subsequently, the performance to discover BC of the miR-93-5p, miR-516a-5p was further verified with an area under ROC curve (AUC) of 0.838 and 0.790, respectively, which was significantly higher than that of urine cytology (AUC = 0.630). Moreover, miR-93-5p was significantly increased in muscle-invasive BC compared with non-muscle-invasive BC with an AUC of 0.769. Bioinformatic analysis revealed that B-cell translocation gene 2(BTG2) gene may be the hub target gene of miR-93-5p. In vitro experiments verified that miR-93-5p suppressed BTG2 expression and promoted BC cells proliferation, invasion and migration.ConclusionUrine derived exosomes have a distinct miRNA profile in BC patients, and urinary exosomal miRNAs could be used as a promising non-invasive tool to detect BC. In vitro experiments suggested that miR-93-5p overexpression may contribute to BC progression via suppressing BTG2 expression.

Ribonucleic acid-binding protein CPSF6 promotes glycolysis and suppresses apoptosis in hepatocellular carcinoma cells by inhibiting the BTG2 expression

Hepatocellular carcinoma (HCC) is currently the sixth most common malignancy and the second major cause of tumor-related deaths in the world. This study aimed to investigate the role of cleavage and polyadenylation factor-6 (CPSF6) and B-cell translocation gene 2 (BTG2) in regulating the glycolysis and apoptosis in HCC cells. The RNA and protein expression of CPSF6 and BTG2 in normal hepatocyte and HCC were, respectively, detected by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis and Western blot analysis. The viability and apoptosis of transfected Huh-7 cells were, respectively, analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) assay. The expression of apoptosis-related proteins and HK-2 in transfected Huh-7 cells was also detected by Western blot analysis. The levels of glucose and lactate in the culture supernatant of transfected Huh-7 cells were, respectively, detected with the glucose assay kit and lactate assay kit. The interaction of CPSF6 and BTG2 was confirmed by RNA binding protein immunoprecipitation (RIP) assay. As a result, CPSF6 expression was increased while BTG2 expression was decreased in Huh-7 cells. Interference with CPSF6 suppressed the viability and glycolysis, and promoted the apoptosis of Huh-7 cells. Furthermore, CPSF6 interacted with BTG2 and interference with CPSF6 upregulated the BTG2 expression and inhibited the protein kinase B (AKT)/extracellular signal-regulated kinase (ERK)/nuclear factor (NF)-κB pathway. Interference with BTG2 could partially reverse the above cell changes caused by interference with CPSF6. In conclusion, CPSF6 inhibited the BTG2 expression to promote glycolysis and suppress apoptosis in HCC cells by activating AKT/ERK/NF-κB pathway.

MiR-365 secreted from M2 Macrophage-derived extracellular vesicles promotes pancreatic ductal adenocarcinoma progression through the BTG2/FAK/AKT axis.

Clinical and experimental evidence indicates that tumour‐associated macrophages support cancer progression. Moreover, macrophage‐derived extracellular vesicles (EVs) are involved in pathogenesis of multiple cancers, yet the functions of molecular determinants in which have not been fully understood. Herein, we aim to understand whether macrophage modulates pancreatic ductal adenocarcinoma (PDAC) progression in an EV‐dependent manner and the underlying mechanisms. microRNA (miR)‐365 was experimentally determined to be enriched in the EVs from M2 macrophages (M2‐EVs), which could be transferred into PDAC cells. Using a co‐culture system, M2‐EVs could enhance the proliferating, migrating and invading potentials of PDAC cells, while inhibition of miR‐365 in M2‐EVs could repress these malignant functions. B‐cell translocation gene 2 (BTG2) was identified to be a direct target of miR‐365, while the focal adhesion kinase (F/ATP)‐dependent tyrosine kinase (AKT) pathway was activated by miR‐365. We further demonstrated that overexpression of BTG2 could delay the progression of PDAC in vitro, whereas by impairing BTG2‐mediated anti‐tumour effect, M2‐EV‐miR‐365 promoted PDAC progression. For validation, a nude mouse model of tumorigenesis was established, in which we found that targeting M2‐EV‐miR‐365 contributed to suppression of tumour growth. Collectively, M2‐EVs carry miR‐365 to suppress BTG2 expression, which activated FAK/AKT pathway, thus promoting PDAC development.

Circular RNA circ_0014717 Suppresses Hepatocellular Carcinoma Tumorigenesis Through Regulating miR-668-3p/BTG2 Axis.

Recent studies have reported a close association between circRNAs and cancer development. CircRNAs have been recognized to be involved in various biological processes. Up to now, the function of circRNAs in hepatocellular carcinoma (HCC) is still poorly known. qRT-PCR was used to test circ_0014717 expression in HCC tissue samples and cells was determined. It was shown that circ_0014717 was significantly decreased in HCC. Then, we observed overexpression of circ_0014717 obviously repressed HCC cell growth, migration and invasion. Next, we predicted circ_0014717 acted as a sponge of miR-668-3p. miR-668-3p has been reported to participate in several diseases. In our work, it was shown miR-668-3p was greatly increased in HCC and the direct binding sites between circ_0014717 and miR-668-3p were validated. In addition, B-cell translocation gene 2 (BTG2) is closely involved in cellular carcinogenic processes. BTG2 was predicted as a target for miR-668-3p. By performing rescue assays, we demonstrated that circ_0014717 repressed HCC progression via inhibiting BTG2 expression and sponging miR-668-3p. It was manifested loss of circ_0014717 induced HCC progression, which was reversed by BTG2 in Hep3B cells. In conclusion, our findings illustrated a novel circ_0014717/miR-668-3p/BTG2 regulatory signaling pathway in HCC.

MicroRNA miR-92a-3p regulates breast cancer cell proliferation and metastasis via regulating B-cell translocation gene 2 (BTG2)

ABSTRACT MicroRNAs (miRNAs) dysregulation contributes to tumorigenesis, and it is reported that abnormal miR-92a-3p expression participates in multiple cancers’ occurrence and progression. This study focuses on miR-92a-3p’s functions and regulatory mechanism in breast cancer (BC). The current study proved miR-92a-3p expression was enhanced in BC tissues and cells, and its high expression was related to increased TNM stage and larger tumor size of BC patients. Functionally, transfection of miR-92a-3p mimics facilitated BC cell proliferation and metastasis, yet transfection of miR-92a-3p inhibitors functioned oppositely. In addition, BTG2 was verified as a direct miR-92a-3p target in BC cells. This research indicated that miR-92a-3p facilitates BC cell proliferation and metastasis through repressing BTG2 expression.

LINC01089 inhibits the progression of cervical cancer via inhibiting miR-27a-3p and increasing BTG2.

Increasing evidence confirms that long non-coding RNA (lncRNA) has a vital impact on the procession of cervical cancer (CC). The present study aimed to investigate the clinical significance of LINC01089 in CC, as well as explore its biological functions and potential molecular mechanisms. A quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to investigate the expression of LINC01089 and miR-27a-3p in CC cells and tissues. Analysis of the correlation between the expression level of LINC01089 and the clinical pathological parameters of CC was then conducted. The human CC cell lines HeLa and SiHa were utilized for transfection to establish a gain-of-function model and loss-of-function models. Western blotting and a qRT-PCR were performed to detect B-cell translocation gene-2 (BTG2) expression in CC cells. Cell counting kit (CCK)-8 and 5-bromo-2-deoxyuridine (BrdU) assays were performed to detect the proliferation of CC cells. The transwell method was employed to evaluate the migration and invasion of CC cells. The interactions between LINC01089 and miR-27a-3p were verified by bioinformatics, a dual luciferase reporter gene experiment and a RNA immunoprecipitation experiment, respectively. The expression of LINC01089 in CC was markedly down-regulated. The low expression of LINC01089 in CC was closely associated with a larger tumor size and positive lymph node metastasis. Moreover, overexpression of LINC01089 impeded the proliferation and metastasis of CC cells, whereas knockdown of LINC01089 had the opposite biological functions. In terms of mechanism, LINC01089 could sponge miR-27a-3p and indirectly up-regulate BTG2 expression. LINC01089, as a tumor suppressor, impedes the development of CC by targeting miR-27a-3p to up-regulate BTG2 expression.

MiR-487a performs oncogenic functions in osteosarcoma by targeting BTG2 mRNA.

Aberrant microRNA (miRNA) expression plays a critical role in osteosarcoma (OS) pathogenesis. In this study, we elucidated the involvement of miR-487a in OS and the underlying molecular mechanisms. We found that miR-487a was upregulated in OS clinical samples and cell lines. Knockdown of miR-487a suppressed OS cell growth and invasion and induced apoptosis; however, overexpression of miR-487a promoted OS cell growth and invasion. Accordingly, downregulation of miR-487a significantly suppressed tumor growth of OS xenografts in vivo. Furthermore, B-cell translocation gene 2 (BTG2) mRNA was found to be a novel target of miR-487a. Knockdown of BTG2 using small interfering RNA (siRNA) recapitulated the oncogenic effects of miR-487a, whereas BTG2 overexpression partially reversed these effects. Finally, miR-487a levels were found to be negatively correlated with BTG2 expression in OS clinical samples. Collectively, our data suggest that miR-487a is an oncogenic miRNA in OS and it lowers BTG2 expression.

Estradiol Prevents High Glucose-Induced \u03b2-cell Apoptosis by Decreased BTG2 Expression

Hyperglycemia stimulates several pathways to induce pancreatic β-cell apoptosis. In our previous study by mRNA analysis, we demonstrated that B-cell translocation gene 2 (BTG2) expression was up-regulated in INS-1 cells cultured under high glucose conditions, but this effect was reversed by estrogen. In the present study, we demonstrated that BTG2 mRNA and protein expressions in both INS-1 cells and mouse pancreatic islets increased under high glucose conditions compared to those cultured under basal glucose conditions, while in the presence of estrogen, the BTG2 mRNA and protein expressions decreased. SiRNA-BTG2 significantly reduced cell apoptosis, cleaved-caspase 3, and Bax, compared to the siRNA-control in INS-1 cultured under high glucose conditions. We further demonstrated that BTG2 promoter activity was activated under high glucose conditions whereas estrogen significantly reduced it. The effects of estrogen on BTG2 expression were inhibited by estrogen receptor inhibitors. Also, under high glucose conditions, p53 and Bax mRNA and protein expressions increased, but they decreased in the presence of estrogen. Again, the effect of estrogen on p53 and Bax expression was inhibited by estrogen receptor inhibitors. Taken together, this study demonstrates that estrogen reduces pancreatic β-cell apoptosis under high glucose conditions via suppression of BTG2, p53, and Bax expressions.

Abstract LB-159: A multi-omic study reveals BTG2 as a reliable prognostic marker for early-stage non-small cell lung cancer

Abstract Background B-cell translocation gene 2 (BTG2), which functions as a tumor suppress gene, has been reported to be involved in several cancers. However, no study has focused on its role in lung cancer progression or prognosis. We aimed to investigate the role of BTG2 in early-stage non-small cell lung cancer (NSCLC) survival. Patients and methods This study included 1,230 early-stage (1-2) surgically treated NSCLC patients with methylation and expression data from five international cohorts. We built a prognostic model based on methylation. Then, we explored BTG2 expression and NSCLC survival in 3,038 cases, including the above-mentioned cohorts as well as 17 extended public datasets by meta-analysis. Further, we integrated the clinical information, expression, and methylation to build an integration model and evaluated its prediction ability for 5-year survival. Results Three risk CpG probes (cg01798157, cg06373167, cg23371584) were associated with overall survival. The prognostic model could distinguish patient survival in the four cohorts [hazard ratio (HR) range, 1.51 to 2.21] and the independent validation set (HR = 1.85). In the expression analysis, BTG2 acted as a tumor-suppress gene in each cohort (HR range, 0.28 to 0.68). A meta-analysis showed high BTG2 expression was associated with better survival (HR = 0.61, 95%CI: 0.54-0.68). The three CpG probes were all negatively correlated with BTG2 expression. Additionally, the integration model showed a better prediction ability in the training set [area under the curve (AUC) = 0.78] and the validation set (AUC = 0.77). The integrated signature showed a better predictive ability among cases with adjuvant therapy (AUC = 0.85). In addition, 17 miRNAs including miR-21 and miR-23a were associated with BTG2 expression and survival. Conclusions: methylation and integrated prognostic signatures of BTG2 are stable and reliable biomarkers for early-stage NSCLC. These markers may have new applications for appropriate clinical adjuvant trials and personalized treatments in the future. Citation Format: Sipeng Shen, Li Su, Ruyang Zhang, Elizabeth Loehrer, Michael Lanuti, Nancy Diao, David Christiani. A multi-omic study reveals BTG2 as a reliable prognostic marker for early-stage non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-159.

A multi-omic study reveals BTG2 as a reliable prognostic marker for early-stage non-small cell lung cancer.

B‐cell translocation gene 2 (BTG2) is a tumour suppressor protein known to be downregulated in several types of cancer. In this study, we investigated a potential role for BTG2 in early‐stage non‐small cell lung cancer (NSCLC) survival. We analysed BTG2 methylation data from 1230 early‐stage NSCLC patients from five international cohorts, as well as gene expression data from 3038 lung cancer cases from multiple cohorts. Three CpG probes (cg01798157, cg06373167, cg23371584) that detected BTG2 hypermethylation in tumour tissues were associated with lower overall survival. The prognostic model based on methylation could distinguish patient survival in the four cohorts [hazard ratio (HR) range, 1.51–2.21] and the independent validation set (HR = 1.85). In the expression analysis, BTG2 expression was positively correlated with survival in each cohort (HR range, 0.28–0.68), which we confirmed with meta‐analysis (HR = 0.61, 95% CI 0.54–0.68). The three CpG probes were all negatively correlated with BTG2 expression. Importantly, an integrative model of BTG2 methylation, expression and clinical information showed better predictive ability in the training set and validation set. In conclusion, the methylation and integrated prognostic signatures based on BTG2 are stable and reliable biomarkers for early‐stage NSCLC. They may have new applications for appropriate clinical adjuvant trials and personalized treatments in the future.

Inhibition of TNF\u03b1-interacting protein \u03b1 (Tip\u03b1)-associated gastric carcinogenesis by BTG2/TIS21 via downregulating cytoplasmic nucleolin expression

To understand the regulation of Helicobacter pylori (H. pylori)-associated gastric carcinogenesis, we examined the effect of B-cell translocation gene 2 (BTG2) expression on the biological activity of Tipα, an oncoprotein secreted from H. pylori. BTG2, the human ortholog of mouse TIS21 (BTG2/TIS21), has been reported to be a primary response gene that is transiently expressed in response to various stimulations. Here, we report that BTG2 is constitutively expressed in the mucous epithelium and parietal cells of the gastric gland in the stomach. Expression was increased in the mucous epithelium following H. pylori infection in contrast to its loss in human gastric adenocarcinoma. Indeed, adenoviral transduction of BTG2/TIS21 significantly inhibited Tipα activity in MKN-1 and MGT-40, human and mouse gastric cancer cells, respectively, thereby downregulating tumor necrosis factor-α (TNFα) expression and Erk1/2 phosphorylation by reducing expression of nucleolin, a Tipα receptor. Chromatin immunoprecipitation proved that BTG2/TIS21 inhibited Sp1 expression and its binding to the promoter of the nucleolin gene. In addition, BTG2/TIS21 expression significantly reduced membrane-localized nucleolin expression in cancer cells, and the loss of BTG2/TIS21 expression induced cytoplasmic nucleolin availability in gastric cancer tissues, as evidenced by immunoblotting and immunohistochemistry. Higher expression of BTG2 and lower expression of nucleolin were accompanied with better overall survival of poorly differentiated gastric cancer patients. This is the first report showing that BTG2/TIS21 inhibits nucleolin expression via Sp1 binding, which might be associated with the inhibition of H. pylori-induced carcinogenesis. We suggest that BTG2/TIS21 is a potential inhibitor of nucleolin in the cytoplasm, leading to inhibition of carcinogenesis after H. pylori infection.

MiR-25-3p promotes the proliferation of triple negative breast cancer by targeting BTG2

BackgroundTriple-negative breast cancer (TNBC) is highly invasive and aggressive and lacks specific molecular targets to improve the prognosis. MiR-25-3p promotes proliferation of many tumors and its role and underlying mechanisms in TNBC remain to be well elucidated.MethodsDifferential expression of miR-25-3p in TNBC was measured with quantitative real-time PCR (qRT-PCR) in both TNBC tissues and cell lines and was validated in the Cancer Genome Atlas (TCGA) database. The effects of miR-25-3p on proliferation, apoptosis capacity of TNBC were evaluated using Cell counting kit-8 (CCK-8), colony formation assay and Annexin V-FITC/PI analyses. The tumor growth in vivo was observed in xenograft model. Luciferase reporter assay, qPCR and western blot were performed to validate a potential target of miR-25-3p in TNBC. Involvement of the AKT and MAPK pathways was investigated by western blot.ResultsMiR-25-3p was found to be upregulated in TNBC in tissues and cell lines. MiR-25-3p promoted TNBC cell proliferation in vitro and tumor growth in xenograft model, while suppression of miR-25-3p induced cell apoptosis. The luciferase reporter assay confirmed that B-cell translocation gene 2 (BTG2) might be a direct target of miR-25-3p, and its expression was negatively regulated by miR-25-3p. Moreover, inhibition of BTG2 expression accounted for the role of miR-25-3p in TNBC. Furthermore, BTG2 suppression might indirectly activate the AKT and ERK-MAPK signaling pathways to mediate the downstream effects of miR-25-3p.ConclusionsThis study demonstrates that miR-25-3p promotes proliferation by targeting tumor suppressor BTG2 and may identify new diagnostic and therapeutic targets in TNBC.

BTG2 is a tumor suppressor gene upregulated by p53 and PTEN in human bladder carcinoma cells.

Although widely deemed as a tumor suppressor gene, the role of B‐cell translocation gene 2 (BTG2) in bladder cancer is still inconclusive. We investigated the role and regulatory mechanism of BTG2 in bladder cancer. BTG2 expression in human bladder tissues was determined by RT‐qPCR and immunoblotting assays. Expressions of BTG2 and PTEN in bladder carcinoma cells were determined by immunoblotting, RT‐qPCR, or reporter assays. The 3H‐thymidine incorporation assay, flow cytometry, and the xenograft animal model were used to determine the cell growth. BTG2 expression was lower in human bladder cancer tissues than normal bladder tissues. Highly differentiated bladder cancer cells, RT4, expressed higher BTG2 than the less‐differentiated bladder cancer cells, HT1376 and T24. Overexpression of BTG2 in T24 cells inhibited cell growth in vitro and in vivo. Camptothecin and doxorubicin treatments in RT‐4 cells or transient overexpression of p53 into p53‐mutant HT1376 cells induced p53 and BTG2 expression. Further reporter assays with site‐mutation of p53 response element from GGGAAAGTCC to GGAGTCC within BTG2 promoter area showed that p53‐induced BTG2 gene expression was dependent on the p53 response element. Ectopic PTEN overexpression in T24 cells blocked the Akt signal pathway which attenuated cell growth via upregualtion of BTG2 gene expression, while reverse effect was found in PTEN‐knockdown RT‐4 cells. PTEN activity inhibitor (VO‐OHpic) treatment decreased BTG2 expression in RT‐4 and PTEN‐overexpressed T24 cells. Our results suggested that BTG2 functioned as a bladder cancer tumor suppressor gene, and was induced by p53 and PTEN. Modulation of BTG2 expression seems a promising way to treat human bladder cancer.

BTG2 Is Down-Regulated and Inhibits Cancer Stem Cell-Like Features of Side Population Cells in Hepatocellular Carcinoma.

Our previous study found that B cell translocation gene 2 (BTG2) was hyper-methylated and down-regulated in side population (SP) cells of hepatocellular carcinoma (HCC) cell line. However, its clinical significances and biological impacts on HCC SP cells remained unclear. To investigate the prognostic value of BTG2 gene in HCC and its influences on cancer stem cells (CSCs)-like traits of HCC cell line SP cells. BTG2 expression in human HCC and adjacent non-cancerous tissues was detected by immunohistochemical staining and quantitative real-time PCR, and also obtained from GEO and TCGA data. Its prognostic values were assessed. Its biological influences on HCC cell line SP cells were evaluated using cell viability, cell cycle, plate clone-forming assay, and chemoresistance in vitro and tumorigenicity in vivo. BTG2 expression was significantly suppressed in human HCC compared to adjacent non-cancerous tissues. BTG2 expression was correlated with TNM stage, tumor size and vascular invasion. Lower expression of BTG2 was associated with poorer overall survival and disease-free survival. In vitro, overexpression of BTG2 substantially suppressed cell proliferation and accumulation of HCC cell line SP cells in G0/G1 phase. Colony formation ability was markedly suppressed by BTG2 overexpression. Moreover, sensitivity of HCC cell line SP cells to 5-fluorouracil was substantially increased by overexpression of BTG2. Furthermore, tumorigenicity of HCC cell line SP cells transfected with BTG2 plasmids was significantly reduced in vivo. BTG2 gene could regulate the CSC-like traits of HCC cell line SP cells, and it represented as a molecular prognostic marker for HCC.

Expression of B-cell translocation gene 2 is associated with favorable prognosis in hepatocellular carcinoma patients and sensitizes irradiation-induced hepatocellular carcinoma cell apoptosis in vitro and in nude mice.

B-cell translocation gene 2 (BTG2) proteins have been reported to be putative tumor suppressors in various cancer types. The present study first assessed BTG2 expression in 44 human liver cancer tissue specimens, then investigated BTG2 expression in the regulation of hepatocellular carcinoma (HCC) cell apoptosis with or without radiotherapy in vitro and in vivo. The results revealed that BTG2 protein expression was significantly reduced in HCC tissues, and associated with better survival for HCC patients (P=0.05). BTG2 overexpression also sensitized Huh7 cells to radiation-induced apoptosis in vitro and in a nude mouse model, although restoration of BTG2 expression per se did not affect the viability and apoptosis of HCC cells. Future studies would confirm the role of BTG2 in hepatoma, and further develop BTG2 as a therapeutic strategy for controlling HCC.