Transducin-like Enhancer Of Split Research Articles

BCOR overexpression in pediatric sarcomas- a morphologic continuum of mixed round and spindle cell tumors

Objectives The vast majority of BCOR (BCL6 corepressor) sarcomas occur in the pediatric population and include different clinico-pathologic entities. This study evaluates morphology, immunohistochemistry and clinical outcome in pediatric BCOR sarcomas. Material and Methods Children, aged ≤ 18yrs, diagnosed to have translocation negative Ewing-like sarcoma, clear cell sarcoma of the kidney and primitive myxoid mesenchymal tumor of infancy, over a period of five years were included. Immunohistochemical staining for BCOR antibody was done and the cases with BCOR overexpression were subjected to a further immunopanel comprising of special AT-rich sequence-binding protein 2 (SATB2), Transducin-Like enhancer of split-1 (TLE1), Cyclin D1 and NKX2.2. The clinical outcome of patients with BCOR overexpression was assessed. Results BCOR overexpression was seen in 16/42 cases; Five were primary soft tissue tumors, three were primary bone tumors, seven were clear cell sarcoma of the kidney and one primary renal sarcoma. The median age of this group was 3.5 years (range 2–18 years) with male predominance (75%). All the BCOR positive tumors showed statistically significant morphological and immunohistochemical overlap. 4/16 did not take treatment at our center. Of the 12 who received treatment, 8 are in Complete Remission 1 (CR1). The mean event-free survival (EFS) and overall survival (OS) were 51.89 months (95% CI: 37.36-66.42) and 62.08 months (95% confidence interval (CI): 52.85-71.30) respectively. Conclusion BCOR sarcomas did not show any statistically significant histological and immunohistochemical differences, thus reiterating the morphologic continuum of these clinically distinct tumors.

Abstract 5831: The TLE1 transcriptional and epigenetic machinery contributes to EGFR targeted therapy resistance in human lung adenocarcinoma

Abstract In human lung adenocarcinoma that carry Epidermal Growth Factor Receptor (EGFR) sensitizing mutations, targeting the EGFR pathway with the use of EGFR tyrosine kinase inhibitors (EGFR-TKIs) has emerged as a promising therapeutic strategy providing initial clinical benefit to many patients. Unfortunately, resistance to EGFR-TKIs eventually develops leading to disease progression. In addition to genetic mutations, transcriptional and epigenetic mediated changes in gene expression remain an important mechanism contributing to EGFR-TKI resistance. Here, we report a novel function of the transcriptional corepressor Transducin-Like Enhancer of Split-1 (TLE1) in mediating EGFR-TKI resistance in EGFR mutant LUAD cells through its survival promoting gene transcriptional program. In EGFR mutant, EGFR TKI sensitive LUAD cells, sole activation of the TLE1 nuclear function attenuates EGFR TKI sensitivity with concomittant reduction of EGFR-TKI-mediated apoptosis. Conversely, downregulation of endogenous TLE1 expression via siRNAs/shRNAs and deletion of TLE1 gene via CRISPR-Cas9 in EGFR-mutant, EGFR-TKI resistant cells partially restore EGFR-TKI sensitivity via induction of EGFR-TKI apoptosis. Mechanistically, the anti-apoptosis promoting gene transcriptional program of TLE1 is dependent on its functional interaction with the transcriptional repressor HES-1, a downstream Notch target which has been associated with relapse in LUAD patients following EGFR-TKI treatment. Collectively, these studies indicate the TLE1 corepressor as a determinant of resistance to EGFR targeted therapy and raise the possibility that inhibiting TLE1 nuclear function may serve as an adjuct therapy to circumvent EGFR-TKI resistance. Citation Format: Hector Ramos Biliran, Xin Yao, Nasir Roberts, Prince Iheukwumere, Renwei Chen, Ma. Carmela Dela Cruz. The TLE1 transcriptional and epigenetic machinery contributes to EGFR targeted therapy resistance in human lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5831.

TLE4 downregulation identified by WGCNA and machine learning algorithm promotes papillary thyroid carcinoma progression via activating JAK/STAT pathway.

Background: Papillary Thyroid Carcinoma (PTC), a common type of thyroid cancer, has a pathogenesis that is not fully understood. This study utilizes a range of public databases, sophisticated bioinformatics tools, and empirical approaches to explore the key genetic components and pathways implicated in PTC, particularly concentrating on the Transducin-Like Enhancer of Split 4 (TLE4) gene. Methods: Public databases such as TCGA and GEO were utilized to conduct differential gene expression analysis in PTC. Hub genes were identified using Weighted Gene Co-expression Network Analysis (WGCNA), and machine learning techniques, including Random Forest, LASSO regression, and SVM-RFE, were employed for biomarker identification. The clinical impact of the TLE4 gene was assessed in terms of diagnostic accuracy, prognostic value, and its functional enrichment analysis in PTC. Additionally, the study focused on understanding the role of TLE4 in the dynamics of immune cell infiltration, gene function enhancement, and behaviors of PTC cells like growth, migration, and invasion. To complement these analyses, in vivo studies were performed using a xenograft mouse model. Results: 244 genes with significant differential expression across various databases were identified. WGCNA indicated a strong link between specific gene modules and PTC. Machine learning analysis brought the TLE4 gene into focus as a key biomarker. Bioinformatics studies verified that TLE4 expression is lower in PTC, linking it to immune cell infiltration and the JAK-STAT signaling pathways. Experimental data revealed that decreased TLE4 expression in PTC cell lines leads to enhanced cell growth, migration, invasion, and activates the JAK/STAT pathway. In contrast, TLE4 overexpression in these cells inhibited tumor growth and metastasis. Conclusions: This study sheds light on TLE4's crucial role in PTC pathogenesis, positioning it as a potential biomarker and target for therapy. The integration of multi-omics data and advanced analytical methods provides a robust framework for understanding PTC at a molecular level, potentially guiding personalized treatment strategies.

The Tbx20-TLE interaction is essential for the maintenance of the second heart field.

T-box transcription factor 20 (Tbx20) plays a multifaceted role in cardiac morphogenesis and controls a broad gene regulatory network. However, the mechanism by which Tbx20 activates and represses target genes in a tissue-specific and temporal manner remains unclear. Studies show that Tbx20 directly interacts with the Transducin-like Enhancer of Split (TLE) family of proteins to mediate transcriptional repression. However, a function for the Tbx20-TLE transcriptional repression complex during heart development has yet to be established. We created a mouse model with a two amino acid substitution in the Tbx20 EH1 domain, thereby disrupting the Tbx20-TLE interaction. Disruption of this interaction impaired crucial morphogenic events, including cardiac looping and chamber formation. Transcriptional profiling of Tbx20EH1Mut hearts and analysis of putative direct targets revealed misexpression of the retinoic acid pathway and cardiac progenitor genes. Further, we show that altered cardiac progenitor development and function contribute to the severe cardiac defects in our model. Our studies indicate that TLE-mediated repression is a primary mechanism by which Tbx20 controls gene expression.

Phenethyl isothiocyanate inhibits metastasis potential of non-small cell lung cancer cells through FTO mediated TLE1 m6A modification.

N6-methyladenosine (m6A) modification is a prevalent RNA epigenetic modification, which plays a crucial role in tumor progression including metastasis. Isothiocyanates (ITCs) are natural compounds and inhibit the tumorigenesis of various cancers. Our previous studies show that ITCs inhibit the proliferation and metastasis of non-small cell lung cancer (NSCLC) cells, and have synergistic effects with chemotherapy drugs. In this study, we investigated the molecular mechanisms underlying the inhibitory effects of ITCs on cancer cell metastasis. We showed that phenethyl isothiocyanate (PEITC) dose-dependently inhibited the cell viability of both NSCLC cell lines H1299 and H226 with IC50 values of 17.6 and 15.2 μM, respectively. Furthermore, PEITC dose-dependently inhibited the invasion and migration of H1299 and H226 cells. We demonstrated that PEITC treatment dose-dependently increased m6A methylation levels and inhibited the expression of the m6A demethylase fat mass and obesity-associated protein (FTO) in H1299 and H226 cells. Knockdown of FTO significantly increased m6A methylation in H1299 and H226 cells, impaired their abilities of invasion and migration in vitro, and enhanced the inhibition of PEITC on tumor growth in vivo. Overexpression of FTO promoted the migration of NSCLC cells, and also mitigated the inhibitory effect of PEITC on migration of NSCLC cells. Furthermore, we found that FTO regulated the mRNA m6A modification of a transcriptional co-repressor Transducin-Like Enhancer of split-1 (TLE1) and further affected its stability and expression. TCGA database analysis revealed TLE1 was upregulated in NSCLC tissues compared to normal tissues, which might be correlated with the metastasis status. Moreover, we showed that PEITC suppressed the migration of NSCLC cells by inhibiting TLE1 expression and downstream Akt/NF-κB pathway. This study reveals a novel mechanism underlying ITC's inhibitory effect on metastasis of lung cancer cells, and provided valuable information for developing new therapeutics for lung cancer by targeting m6A methylation.

Expression of TLE1 in a Carcinoid Tumor of the Lung With Spindle Cell Morphology-A Potential Diagnostic Pitfall.

Tumors of the lung with a spindle cell morphology require consideration of many entities in the differential diagnosis, including metastases. Ancillary immunohistochemical stains but also molecular studies are typically required to arrive at the proper diagnosis. We present a case of a 71-year-old woman with multiple lung nodules, mediastinal lymphadenopathy, and a history of uterine cancer who underwent endobronchial ultrasound-guided fine needle aspiration and biopsy of the lung and mediastinal lymph nodes. A sampling of the lung lesion showed a cytologically bland neoplasm with spindle cell morphology, lacking necrosis or brisk mitotic activity. In conjunction with the cytomorphology, strong and diffuse Transducin-like enhancer of split 1 (TLE1) reactivity in the tumor cells initially raised the diagnosis of synovial sarcoma; however, subsequent results of additional testing showed strong and diffuse expression with AE1/AE3, CK 8/18, TTF-1, synaptophysin and chromogranin and focal or negative staining with a large number of other antibodies. This warranted a diagnosis of a carcinoid tumor. This is the first report of TLE1 staining in a carcinoid tumor of the lung. Therefore, when evaluating tumors of the lung with spindle cell morphology in which the differential diagnosis may include both carcinoid tumor and synovial sarcoma, TLE1 expression should be interpreted with caution and in conjunction with an expanded immunohistochemical staining panel.

Zeb1 and Tle3 are trans-factors that differentially regulate the expression of myosin heavy chain-embryonic and skeletal muscle differentiation.

Myosin heavy chain-embryonic encoded by the Myh3 gene is a skeletal muscle-specific contractile protein expressed during mammalian development and regeneration, essential for proper myogenic differentiation and function. It is likely that multiple trans-factors are involved in this precise temporal regulation of Myh3 expression. We identify a 4230 bp promoter-enhancer region that drives Myh3 transcription in vitro during C2C12 myogenic differentiation and in vivo during muscle regeneration, including sequences both upstream and downstream of the Myh3 TATA-box that are necessary for complete Myh3 promoter activity. Using C2C12 mouse myogenic cells, we find that Zinc-finger E-box binding homeobox 1 (Zeb1) and Transducin-like Enhancer of Split 3 (Tle3) proteins are crucial trans-factors that interact and differentially regulate Myh3 expression. Loss of Zeb1 function results in earlier expression of myogenic differentiation genes and accelerated differentiation, whereas Tle3 depletion leads to reduced expression of myogenic differentiation genes and impaired differentiation. Tle3 knockdown resulted in downregulation of Zeb1, which could be mediated by increased expression of miR-200c, a microRNA that binds to Zeb1 transcript and degrades it. Tle3 functions upstream of Zeb1 in regulating myogenic differentiation since double knockdown of Zeb1 and Tle3 resulted in effects seen upon Tle3 depletion. We identify a novel E-box in the Myh3 distal promoter-enhancer region, where Zeb1 binds to repress Myh3 expression. In addition to regulation of myogenic differentiation at the transcriptional level, we uncover post-transcriptional regulation by Tle3 to regulate MyoG expression, mediated by the mRNA stabilizing Human antigen R (HuR) protein. Thus, Tle3 and Zeb1 are essential trans-factors that differentially regulate Myh3 expression and C2C12 cell myogenic differentiation in vitro.

ALL-017 Adult T-Cell Acute Lymphoblastic Leukemia With Transducin-Like Enhancer Gene Expression

Transducin-like enhancer of split 1 (TLE1) is a member of the TLE family of transcriptional co-repressors that control the transcription of a wide range of genes. The aim of this study was to evaluate the prognostic role of TLE1 gene expression in patients with T-cell acute lymphoblastic leukemia (T-ALL). This study was conducted on 97 newly diagnosed T-ALL patients admitted to the Mansoura University oncology center (59 males and 38 females) with median age 33 years, in addition to 102 apparently healthy individuals who served as a control group. TLE1 gene expression was measured in both patients and control groups by real time - PCR. The calculation of relative gene expression was done using the AACt method. TEL1 gene expression was significantly down regulated in T-ALL cases (median 2.83) as compared to controls (median 84.65) (p < 0.001). Low TEL1 gene expression was significantly associated with CNS infiltration, failure to achieve 1st complete remission and higher relapse rate (p< 0.001, 0.001 and 0.023, respectively). Early T-cell precursor (ETP)-ALL/LBL subtype was found to be significantly associated with low TEL1 gene expression (P 0.04), however there was no relation between TEL1 gene expression and TCR rearrangement or other available molecular abnormalities. Likewise, low TEL1 gene expression was significantly associated with shorter overall survival (OS) and disease-free survival (DFS) (P= 0.012 and 0.011, respectively). Furthermore, Low TEL1 gene expression was considered a risk predictor of relapse with OR 3.636(CI.1.422-9.295) (P =0.007); and OR 0.803(CI. 0.609-0.96) (P=0.021) and an independent predictor of T-ALL patients' outcomes with OR 0.619 (CI. 0.44-0.872) (P=0.006). TLE1 gene expression was significantly down regulated in T-ALL as compared with controls. Low TLE1 expression is an independent predictor of the T-ALL patient's outcome and could open the way for further risk stratification and targeted therapy in T-ALL.

ALL-234: TLE1 Gene Expression in Adult T-Cell Acute Lymphoblastic Leukemia

<h3>Background:</h3> Transducin-like enhancer of split 1 (TLE1) is a member of the TLE family of transcriptional co-repressors that control the transcription of a wide range of genes. The aim of this study was to evaluate the prognostic role of TLE1 gene expression in patients with T-cell acute lymphoblastic leukemia (T-ALL). <h3>Method:</h3> This study was conducted on 97 newly diagnosed T-ALL patients admitted to the Mansoura University Oncology Center (59 males and 38 females), with a median age of 33 years, in addition to 102 apparently healthy individuals who served as a control group. TLE1 gene expression was measured in both the patient and control groups by real-time PCR. The calculation of relative gene expression was done using the δδCt: method. <h3>Results:</h3> TEL1 gene expression was significantly downregulated in T-ALL cases (median 2.83) compared to controls (median 84.65; P<0.001). Low TEL1 gene expression was significantly associated with CNS infiltration, failure to achieve the first complete remission, and a higher relapse rate (P<0.001, 0.001, and 0.023, respectively). The early T-cell precursor (ETP)-ALL/LBL subtype was found to be significantly associated with low TEL1 gene expression (P=0.04); however, no relations between TEL1 gene expression and TCR rearrangement or other known molecular abnormalities were found. Likewise, low TEL1 gene expression was significantly associated with shorter OS and DFS (P=0.012 and 0.011, respectively). Furthermore, low TEL1 gene expression was considered a risk predictor of relapse, with OR 3.636 (CI: 1.422–9.295; P=0.007) in univariate analysis and OR 0.803 (CI: 0.609–0.96; P=0.021) in multivariate analysis, and an independent predictor of T-ALL patient outcomes, with OR 0.619 (CI:0 .44–0.872; P=0.006). <h3>Conclusion:</h3> TLE1 gene expression was significantly downregulated in T-ALL compared with controls. Low TLE1 expression is an independent predictor of T-ALL patient outcomes and could open avenues for further risk stratification and targeted therapy in T-ALL.

Prognostic Value of TLE1 Gene Expression in Patients with T-cell Acute Lymphoblastic Leukemia.

Background:Transducin-like enhancer of split 1 (TLE1( is a member of the TLE family of transcriptional co-repressors that control the transcription of a wide range of genes. The aim of this study was to evaluate the prognostic role of TLE1 gene expression in patients with T-cell acute lymphoblastic leukemia (T-ALL). Method:This study was conducted on 97 newly diagnosed T-ALL patients admitted to the Mansoura University oncology center (59 males and 38 females) with median age (33 years) in addition to 102 apparently healthy individuals served as a control group. TLE1 gene expression was measured in both patients and control groups by real time – PCR. The calculation of relative gene expression was done using the ΔΔCt method. Results: TEL1 gene expression was significantly down regulated in T-ALL cases (median 2.83) as compared to controls (median 84.65) (p < 0.001). The low TEL1 gene expression was significantly associated with CNS infiltration, non-remission and higher relapse rate (p< 0.001, 0.001 and 0.023 respectively). Likewise, Low TEL1 gene expression was significantly associated with shorter OS and DFS (P= 0.012 and 0.011 respectively). Furthermore, Low TEL1 gene expression was considered as risk predictor of relapse with OR 3.636(CI.1.422-9.295) (P =0.007); and OR 0.803(CI. 0.609-0.96) (P=0.021) and independent predictor of T-ALL patient’s outcome with OR 0.619 (CI. 0.44-0.872) (P=0.006). Conclusion:TLE1 gene expression was significantly down regulated in T-ALL cases as compared with controls. Low TLE1 expression is independent predictor of the T-ALL patient’s outcome.

Loss of histone H3 trimethylation on lysine 27 and nuclear expression of transducin-like enhancer 1 in primary intracranial sarcoma, DICER1-mutant.

Primary intracranial sarcoma, DICER1-mutant is a recently described central nervous system tumour with specific genomic and DNA-methylation profiles. Although some of its histological features (focal spindle-cell morphology, intracytoplasmic eosinophilic granules, and focal heterologous differentiation) are common across most reported cases, the presence of significant histological variability and the lack of differentiation pose diagnostic challenges. We aim to further define the immunoprofile of this tumor. We reviewed the clinical history and performed immunohistochemistry for glial fibrillary acidic protein, oligodendrocyte transcription factor 2, SOX2, SOX10, S100, histone H3 trimethylated on lysine 27 (H3K27me3), desmin, myogenin, CD99, epithelial membrane antigen (EMA) and transducin-like enhancer of split 1 (TLE1) on six primary intracranial sarcomas, DICER1-mutant, with appropriate controls. Targeted exome sequencing was performed on all cases. The sarcomas showed diffuse (n=4), mosaic (n=1) or minimal (≤5%, n=1) loss of H3K27 trimethylation and nuclear TLE1 expression (n=6). Four had immunohistochemical evidence of myogenic differentiation. SOX2, SOX10, S100 and EMA were negative; CD99 expression ranged from focal cytoplasmic (n=4) to crisp diffuse membranous (n=2). One tumour had focal cartilaginous differentiation. Similar immunohistochemical findings were observed in a pleuropulmonary blastoma (albeit with focal TLE1 expression), a DICER1-related pineoblastoma, and an embryonal tumour with a multilayered rosette-like DICER1-related cerebellar tumour. Targeted exome sequencing confirmed the presence of pathogenic biallelic DICER1 mutations in all tumours included in this study. We conclude that H3K27me3 and TLE1 immunostains, when utilised in combination, can be helpful diagnostic markers for primary intracranial sarcoma, DICER1-mutant.

Primary synovial sarcoma thyroid: an unusual presentation

Primary Synovial sarcoma of the thyroid gland is a rare sarcoma. We report a case of synovial sarcoma of the thyroid gland in a 2-yr-old boy presenting with a palpable progressively increasing neck mass, high resolution ultrasound revealed a heterogeneous lesion measuring 5 x 4 cm identified in the right lobe compressing the left lobe. A total thyroidectomy was performed and grossly both the lobes were involved. Histologically, the tumor was a biphasic synovial sarcoma which was confirmed by immunohistochemical markers showing positive expression for vimentin, Epithelial membrane antigen &amp;Transducin-like enhancer of split-1. This is an unusual location for the occurrence of primary synovial sarcoma and aggressive nature the early diagnosis is difficult, and no definite treatment regimens are being defined due to the rarity of neoplasm.

LncRNA RASSF8‑AS1 suppresses the progression of laryngeal squamous cell carcinoma via targeting the miR‑664b‑3p/TLE1 axis.

Long non-coding (lnc)RNAs have been found to play a crucial role in tumor progression. The present study aimed to investigate the association between lncRNA RASSF8-AS1 and laryngeal squamous cell carcinoma (LSCC) and the underlying mechanisms. Reverse transcription-quantitative PCR was used to measure the mRNA expression level of RASSF8-AS1, microRNA(miR)-664b-3p and transducin-like enhancer of split 1 (TLE1) in LSCC. The associations between RASSF8-AS1 and miR-664b-3p, and between miR-664b-3p and TLE1 were investigated using a dual luciferase reporter assay, while the former was further verified using an RNA immunoprecipitation (RIP) assay. The association between RASSF8-AS1 and miR-664b-3p on cell biological functions was investigated in vitro using MTS, colony formation and Transwell assays. The RASSF8-AS1 mRNA expression level was decreased in LSCC cell lines and carcinoma tissues, while overexpression of RASSF8-AS1 reduced the migration, invasion and proliferation abilities of LSCC cells. Furthermore, luciferase and RIP assays confirmed that RASSF8-AS1 was a competitive endogenous (ce)RNA by sponging miR-664b-3p to activate TLE1. miR-664b-3p was negatively modulated by RASSF8-AS1; however, TLE1 was positively regulated by RASSF8-AS1. Functionally, RASSF8-AS1 acted as a ceRNA to upregulate TLE1 by sponging miR-664b-3p. In conclusion, the RASSF8-AS1/miR-664b-3p/TLE1 axis acts by suppressing LSCC progression and may provide a novel insight for the molecular mechanism of LSCC.

Spectrum of Synovial Sarcoma-clinicopathological and Immunohistochemical Correlation

Background: Synovial sarcoma is the common adult soft tissue sarcomas affects the lower extremities. In poor resource settings, characterization by molecular methods may not be feasible always. This study is aimed to evaluate Sensitivity and Specificity of Transducin-like enhancer of split 1 (TLE1) immunohistochemical expression in Synovial sarcomas (SS) and its histological mimics and to study the clinicopathological features of Synovial sarcoma.&#x0D; Method: A prospective study of two years duration from September 2013 to September 2015 conducted at the Department of Pathology, MNJ Institute of Oncology and Regional Cancer Centre, Redhills, Hyderabad. Total number of Synovial sarcomas was 30. All original H &amp; E section of the tumor are reviewed and Immunohistochemistry (IHC) analysis was carried out on TLE1 mouse monoclonal antibody (TMA) blocks using TLE1 Antibody.&#x0D; Results: The Median age was 30 years. The most common site of involvement was lower limbs. The most common mode of presentation was painless swelling. The most common variant of Synovial sarcoma was monophasic Spindle in 19 cases. Total number of TLE1 positive cases of Synovial sarcoma was 93.3%. Total number of SS mimics showing TLE1 positivity was30%. TLE1 showed Sensitivity 93.3% and Specificity- 73.3%. In the present study negative predictive value is 91.6% and the positive predictive value is 77.7%.&#x0D; Conclusion: All small round blue cell tumors should be kept in mind while diagnosing poorly differentiated SS. TLE1 is a very sensitive marker for synovial sarcoma.TLE 1 is a highly sensitive marker for synovial sarcoma, but is less specific because of its positive expression in other mesenchymal tumors.

TLE2 is associated with favorable prognosis and regulates cell growth and gemcitabine sensitivity in pancreatic cancer.

BackgroundThe transducin-like enhancer of split (TLE) proteins are a group of transcriptional corepressors. They play a crucial role in cellular homeostasis and are involved in various cancers. Compared with other TLE family members, little is known about the role and the underlying mechanism of TLE2 in human cancers. This study aimed to investigate the role of TLE2 in pancreatic ductal adenocarcinoma (PDAC) using in silico analysis and in vitro experiments.MethodsData were obtained from the Cancer Genome Atlas (TCGA) database to evaluate the prognostic value of TLE2 in PDAC. The MiaPaCa-2 cell line was transfected with siRNA to inhibit endogenous TLE2 expression, and a PANC-1 cell line with stable TLE2 overexpression was constructed using lentiviral transfection, which were confirmed by real-time polymerase chain reaction and western blotting. MTT assay, transwell invasion assays, and flow cytometry were carried out to assess cell viability, invasion, and apoptosis, respectively. TLE2 expression in PDAC cells was altered to evaluate their sensitivity to gemcitabine. Gene set enrichment analysis (GSEA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were conducted to predict the biological role of TLE2.ResultsHigh expression of TLEs was significantly associated with increased overall survival (OS) and disease-free survival (DFS) in patients with PDAC. Among the PDAC cell lines, TLE2 expression was lowest and highest in PANC-1 cells and MiaPaCa-2 cells, respectively. TLE2 overexpression impaired the proliferation ability of PANC-1 cells and downregulation of TLE2 promoted the proliferation of MiaPaCa-2 cells. Upregulation of TLE2 in PANC-1 cells induced S-phase accumulation and sensitivity to gemcitabine. In contrast, the downregulation of TLE2 in MiaPaCa-2 cells promoted resistance to gemcitabine. Moreover, bioinformatics analysis also revealed the potential tumor suppressor role of TLE2 and uncovered a close relationship between TLE2 expression and cell cycle regulation.ConclusionsOur results suggest that TLE2 expression is correlated with prognosis in patients with PDAC and show that TLE2 plays a central role in the regulation of cell proliferation, the cell cycle, and gemcitabine sensitivity. This study provides new insights and evidence that TLE2 functions as a tumor suppressor gene and prognostic marker in PDAC.

Transducin-Like Enhancer of Split-1 Inhibits Malignant Behaviors in vitro and Predicts a Better Prognosis in Pancreatic Ductal Adenocarcinoma.

Background: Transducin-like enhancer of split-1 (TLE1), a member of the Groucho/TLE family of transcriptional corepressors, has been reported to be involved in the tumorigenesis of various cancers and function as a clinical prognostic indicator. However, the mechanisms and prognostic significance of TLE1 in pancreatic ductal adenocarcinoma (PDAC) have not been elucidated.Methods: In this study, western blot analyses and real-time polymerase chain reaction (RT-PCR) were employed to evaluate the expression of TLE1 and related proteins in PDAC cell lines. Wound healing, transwell migration and invasion, and Cell Counting Kit-8 (CCK-8) assays were used to determine cell line-specific differences in metastasis and proliferation. Flow cytometry was performed for cell cycle detection. RNA sequencing and bioinformatics were undertaken to explore the molecular mechanisms and potential targeted molecules of TLE1. TLE1 expression in tumor and para-tumor tissues was evaluated by tissue microarray-based immunohistochemistry using a semiquantitative method (H-score) in 262 patients with radical PDAC resection. Correlation, Kaplan–Meier survival, univariate, and multivariate analyses were also performed.Results: Our findings showed that TLE1 expression was common in PDAC cell lines. Upregulation of TLE1 inhibited PDAC cell migration, invasion, and proliferation in vitro by delaying the G0/G1 transition. Immunohistochemistry revealed that TLE1 was specifically expressed in the nucleus and at higher levels in tumor tissues compared with para-tumor tissues. Generally, high TLE1 expression was associated with no vascular invasion. In univariate analyses, high TLE1 expression was associated with longer disease-specific survival (DSS) in all patients and in 16 patient subgroups. In multivariate analyses, TLE1 expression was independently associated with DSS in all patients and four patient subgroups.Conclusion: In conclusion, these results suggest that TLE1 has an inhibitory role in PDAC progression and is a favorable prognostic indicator for patients with resectable PDAC.

Synovial Sarcoma of the Nerve-Clinical and Pathological Features: Case Series and Systematic Review.

Synovial sarcoma of the nerve is a rare entity with several cases and case series reported in the literature. Despite an improved understanding of the biology, the clinical course is difficult to predict. To compile a series of patients with synovial sarcoma of the peripheral nerve (SSPN) and assess clinical and pathological factors and their contribution to survival and recurrence. Cases from 2 institutions collected in patients undergoing surgical intervention for SSPN. Systematic review including PubMed and Scopus databases were searched for related articles published from 1970 to December 2018. Eligibility criteria: (1) case reports or case series reporting on SSPN, (2) clinical course and/or pathological features of the tumor reported, and (3) articles published in English. From patients treated at our institutions (13) the average follow-up period was 3.2 yr. Tumor recurrence was seen in 4 cases and death in 3. Systematic review of the literature yielded 44 additional cases with an average follow-up period of 3.6 yr. From pooled data, there were 10 recurrences and 7 deaths (20% and 14%, respectively). Adjuvant treatment used in 62.5% of cases. Immunohistochemical markers used in diagnosis varied widely; the most common are the following: Epithelial membrane antigen (EMA), cytokeratin, vimentin, cluster of differentiation (CD34), and transducin-like enhancer of split 1 (TLE1). Statistical analysis illustrated tumor size and use of chemotherapy to be negative predictors of survival. No other factors, clinically or from pathologist review, were correlated with recurrence or survival. By combining cases from our institution with historical data and performing statistical analysis we show correlation between tumor size and death.

Is TLE1 Expression Limited to Synovial Sarcoma? Our Experience at Shifa International Hospital, Pakistan.

Introduction: Synovial sarcoma (SS) accounts for 10-15 percent of adult soft tissue sarcomas. Transducin-like enhancer of split 1 (TLE1), a transcriptional repressor, is essential in hematopoiesis, neuronal differentiation, and terminal epithelial differentiation. TLE1 proteins inhibit Wnt signaling and other cell fate determination signals, and so have an established role in repressing differentiation. TLE1 has recently been shown to be a highly sensitive and relatively specific marker of SS.Materials and methods: Study design is retrospective, descriptive. A total of 25 cases of SS and 28 of soft tissue lesions were retrieved from the record. TLE1 (clone 1F5) expression was evaluated and scored as negative (<5% of cells positive), 1+ (5-25% of cells positive), 2+ (26-50% of cells positive), or 3+ (>50 % of cells positive).Result: Twenty-four out of twenty-five (96%) cases of SS showed 3+ TLE1 expression. One (4%) case of poorly differentiated SS showed 2+ positivity. 3+ TLE1 positivity was seen in one (100%) case each of infantile fibrosarcoma and low-grade fibromyxoid sarcoma, while two cases (100%) of schwannoma also showed 3+ positivity. All cases of solitary fibrous tumor) (n=2), clear cell sarcoma of tendons and aponeurosis (n=2), embryonal rhabdomyosarcoma (n=1), and de-differentiated liposarcoma (n=2) showed 2+ positivity. 1+ positivity was seen in alveolar soft part sarcoma (n=2), Ewing's sarcoma (n=4), undifferentiated pleomorphic sarcoma (n=1), myxoid liposarcoma (n=1) and malignant peripheral nerve sheath tumor (n=1). TLE1 was negative in all cases of chordomas (n=2), lipomas (n=2), nodular fasciitis (n=2), malignant perivascular epithelioid cell tumor (n=1) and dermatofibrosarcoma protuberans (n=1).Conclusion: TLE1 may be a reliable immunostain for diagnosing SS, but its expression is not limited to SS. Its expression should be interpreted in the light of morphological features and a panel of antibodies.

Transducin-like enhancer of split 3 regulates proliferation of melanoma cells via histone deacetylase activity

Melanoma, one of the most aggressive neoplasms, is characterized by rapid cell proliferation. Transducin-like Enhancer of Split (TLE) is an important regulator of cell proliferation via Histone deacetylase (HDAC) recruitment. Given that HDAC activity is associated with melanoma progression, we examined the relationship between TLE3, a TLE family member, and melanoma. TLE3 expression was increased during the progression of human patient melanoma (p < 0.05). Overexpression of Tle3 in B16 murine melanoma cells led to an increase in cell proliferation (p < 0.01) as well as the number of cyclinD1-positive cells. in vivo injection of mice with B16 cells overexpressing Tle3 resulted in larger tumor formation than in mice injected with control cells (p < 0.05). In contrast, siRNA-mediated knockdown of Tle3 in B16 cells or TLE3 in HMV-II human melanoma cells decreased proliferation (p < 0.01). Treatment of B16 cells with trichostatin A (2.5 μM), a class I and II HDAC inhibitor, prevented the effect s of Tle3 on proliferation. In conclusion, these data indicate that Tle3 is required, at least in part, for proliferation in the B16 mouse melanoma model.

Unique, Intersecting, and Overlapping Roles of C/EBP \u03b2 and CREB in Cells of the Innate Immune System

CREB and C/EBP β signaling pathways are modulated during inflammation and also targeted by Bacillus anthracis edema toxin (ET), but how these factors individually and jointly contribute to changes in immune cell function is poorly understood. Using CRISPR/Cas9 gene editing, macrophage cell lines lacking CREB and isoforms of C/EBP β were generated and analyzed for changes in responses to LPS, ET, and IL-4. Macrophages lacking C/EBP β suppressed induction of IL-10 and Arg1, while IL-6 was increased in these cells following exposure to LPS. Examination of C/EBP β isoforms indicated the 38 kDa isoform was necessary for the expression of IL-10 and Arg1. ChIP-Seq analysis of CREB and C/EBP β binding to targets on the chromosome of human PBMC identified several regions where both factors overlapped in their binding, suggesting similar gene targeting or cooperative effects. Based on the ChIP-Seq data, a panel of previously unknown targets of CREB and C/EBP β was identified and includes genes such as VNN2, GINS4, CTNNBL1, and SULF2. Isoforms of a transcriptional corepressor, transducin-like enhancer of Split (TLE), were also found to have CREB and C/EBP β binding their promoter and were up regulated by ET. Finally, we explore a possible layer of C/EBP β regulation by a protein complex consisting of adenomatous polyposis coli (APC) and PKA. Collectively, these data provide new insights into the role of CREB and C/EBP β as immunosignaling regulators and targets of an important bacterial virulence factor.