Expression of ten-eleven translocation 2 and glutathione-S-transferase pi in colorectal cancer patients with and without type 2 diabetes mellitus.

AIMS: To highlight possible correlations of type 2 diabetes mellitus (T2DM) with microscopic / macroscopic characteristics of colorectal cancer tissues, along with the expression of Ten-Eleven Translocation 2 (TET2) and glutathione-S-transferase pi (GST-pi) proteins.

HLH and TET2 Mutation Presenting after First Cycle of CLL Treatment.

Here we report development of hemophagocytic lymphohistiocytosis (HLH), along with unmasking of a TET2-mutated myeloid neoplasm, after initial doses of bendamustine and rituximab for longstanding chronic lymphocytic leukemia (CLL). After many years of CLL showing minimally progressive lymphocytosis, the patient's white blood cell count began to decline in parallel with neutrophil count, hemoglobin, and platelet count. Bone marrow biopsy showed partial CLL involvement; bendamustine+rituximab therapy was augmented with granulocyte colony-stimulating factor (g-CSF) and romiplostim to mitigate worsening pancytopenia, without response. Laboratory evaluation revealed a pattern supportive of the clinical impression of HLH, while bone marrow biopsy showed persistent CLL, new reticulin fibrosis, megakaryocytic proliferation, and 32% mutated TET2, but no compelling morphologic evidence of hemophagocytosis. The patient recovered with dexamethasone and g-CSF support.

Alterations of the expression of TET2 and DNA 5-hmC predict poor prognosis in Myelodysplastic Neoplasms.

BACKGROUND: Myelodysplastic Neoplasms (MDS) are clonal stem cell disorders characterized by ineffective hematopoiesis and progression to acute myeloid leukemia, myelodysplasia-related (AML-MR). A major mechanism of pathogenesis of MDS is the aberration of the epigenetic landscape of the hematopoietic stem cells and/or progenitor cells, especially DNA cytosine methylation, and demethylation. Data on TET2, the predominant DNA demethylator of the hematopoietic system, is limited, particularly in the MDS patients from India, whose biology may differ since these patients present at a relatively younger age. We studied the expression and the variants of TET2 in Indian MDS and AML-MR patients and their effects on 5-hydroxymethyl cytosine (5-hmC, a product of TET2 catalysis) and on the prognosis of MDS patients. RESULTS: Of the 42 MDS patients, cytogenetics was available for 31 sub-categorized according to the Revised International Prognostic Scoring System (IPSS-R). Their age resembled that of the previous studies from India. Bone marrow nucleated cells (BMNCs) were also obtained from 13 patients with AML-MR, 26 patients with de-novo AML, and 11 subjects with morphologically normal bone marrow. The patients had a significantly lower TET2 expression which was more pronounced in AML-MR and the IPSS-R higher-risk MDS categories. The 5-hmC levels in higher-risk MDS and AML-MR correlated with TET2 expression, suggesting a possible mechanistic role in the loss of TET2 expression. The findings on TET2 and 5-hmC were also confirmed at the tissue level using immunohistochemistry. Pathogenic variants of TET2 were found in 7 of 24 patient samples (29%), spanning across the IPSS-R prognostic categories. One of the variants - H1778R - was found to affect local and global TET2 structure when studied using structural predictions and molecular dynamics simulations. Thus, it is plausible that some pathogenic variants in TET2 can compromise the structure of TET2 and hence in the formation of 5-hmC. CONCLUSIONS: IPSS-R higher-risk MDS categories and AML-MR showed a reduction in TET2 expression, which was not apparent in lower-risk MDS. DNA 5-hmC levels followed a similar pattern. Overall, a decreased TET2 expression and a low DNA 5-hmC level are predictors of advanced disease and adverse outcome in MDS in the population studied, i.e., MDS patients from India.

TET2 Regulates 5-Hydroxymethylcytosine Signature and CD4+ T-Cell Balance in Allergic Rhinitis.

PURPOSE: Previous studies have shown the role of ten-eleven translocation 2 (TET2) in CD4+ T cells. However, its function in CD4+ T cells under allergic inflammation is unclear. We aimed to investigate the epigenomic distribution of DNA 5-hydroxymethylcytosine (5hmC) and the role of TET2 in CD4+ T cells of allergic rhinitis (AR). METHODS: The hMeDIP-seq was performed to identify sequences with 5hmC deposition in CD4+ T cells of AR patients. Tet2-deficient or wild type mice were stimulated with ovalbumin (OVA) to develop an AR mouse model. The histopathology in nasal mucosae, Th1/Th2/Treg/Th17 cell percentage, concentrations of Th-related cytokines, expression of Tets and differential hydroxymethylated genes (DhMG), and the global deposition of 5hmC in sorted CD4+ T cells were detected. RESULTS: Epigenome-wide 5hmC landscape and DhMG in the CD4+ T cells of AR patients were identified. Tet2 depletion did not led to spontaneous inflammation. However, under the stimulation of allergen, OVA, loss of Tet2 resulted in the exacerbation of allergic inflammation, which was characterized by severer allergic symptoms, more inflammatory cells infiltrating the nasal lamina propria, sharper imbalances between Th1/Th2 and Treg/Th17 cells, and excessive secretion of OVA-specific IgE and Th2-related cytokines. Moreover, altered mRNA production of several DhMG and sharp decrease in 5hmC deposition were also observed in Tet2-deficient OVA-exposed mice. CONCLUSIONS: TET2 may regulate DNA 5hmC, DhMG expressions, and CD4+ T cell balance in AR.

TET2 Protects Against Vascular Smooth Muscle Cell Apoptosis and Intimal Thickening in Transplant Vasculopathy.

BACKGROUND: Coronary allograft vasculopathy (CAV) is a devastating sequela of heart transplant in which arterial intimal thickening limits coronary blood flow. There are currently no targeted therapies to prevent or reduce this pathology that leads to transplant failure. Vascular smooth muscle cell (VSMC) phenotypic plasticity is critical in CAV neointima formation. TET2 (TET methylcytosine dioxygenase 2) is an important epigenetic regulator of VSMC phenotype, but the role of TET2 in the progression of CAV is unknown. METHODS: We assessed TET2 expression and activity in human CAV and renal transplant samples. We also used the sex-mismatched murine aortic graft model of graft arteriopathy (GA) in wild-type and inducible smooth muscle-specific Tet2 knockout mice; and in vitro studies in murine and human VSMCs using knockdown, overexpression, and transcriptomic approaches to assess the role of TET2 in VSMC responses to IFNγ (interferon γ), a cytokine elaborated by T cells that drives CAV progression. RESULTS: In the present study, we found that TET2 expression and activity are negatively regulated in human CAV and renal transplant samples and in the murine aortic graft model of GA. IFNγ was sufficient to repress TET2 and induce an activated VSMC phenotype in vitro. TET2 depletion mimicked the effects of IFNγ, and TET2 overexpression rescued IFNγ-induced dedifferentiation. VSMC-specific TET2 depletion in aortic grafts, and in the femoral wire restenosis model, resulted in increased VSMC apoptosis and medial thinning. In GA, this apoptosis was tightly correlated with proliferation. In vitro, TET2-deficient VSMCs undergo apoptosis more readily in response to IFNγ and expressed a signature of increased susceptibility to extrinsic apoptotic signaling. Enhancing TET2 enzymatic activity with high-dose ascorbic acid rescued the effect of GA-induced VSMC apoptosis and intimal thickening in a TET2-dependent manner. CONCLUSIONS: TET2 is repressed in CAV and GA, likely mediated by IFNγ. TET2 serves to protect VSMCs from apoptosis in the context of transplant vasculopathy or IFNγ stimulation. Promoting TET2 activity in vivo with systemic ascorbic acid reduces VSMC apoptosis and intimal thickening. These data suggest that promoting TET2 activity in CAV may be an effective strategy for limiting CAV progression.

Role of Ten eleven translocation-2 (Tet2) in modulating neuronal morphology and cognition in a mouse model of Alzheimer's disease.

Abnormal expression of Ten eleven translocation-2 (Tet2) contributes to the pathogenesis of Alzheimer's disease (AD). However, to date, the role of Tet2 in modulating neuronal morphology upon amyloid-ß (Aß)-induced neurotoxicity has not been shown in a mouse model of AD. Here, we have developed a model of injured mouse hippocampal neurons induced by Aß42 oligomers in vitro. We also investigated the role of Tet2 in injured neurons using recombinant plasmids-induced Tet2 inhibition or over-expression. We found that the reduced expression of Tet2 exacerbated neuronal damage, whereas the increased expression of Tet2 was sufficient to protect neurons against Aß42 toxicity. Our results indicate that the brains of aged APPswe/PSEN1 double-transgenic (2 × Tg-AD) mice exhibit an increase in Aß plaque accumulation and a decrease in Tet2 expression. As a result, we have also explored the underlying mechanisms of Tet2 in cognition and amyloid load in 2 × Tg-AD mice via adeno-associated virus-mediated Tet2 knockdown or over-expression. Recombinant adeno-associated virus was microinjected into bilateral dentate gyrus regions of the hippocampus of the mice. Knocking down Tet2 in young 2 × Tg-AD mice resulted in the same extent of cognitive dysfunction as aged 2 × Tg-AD mice. Importantly, in middle-aged 2 × Tg-AD mice, knocking down Tet2 accelerated the accumulation of Aß plaques, whereas over-expressing Tet2 alleviated amyloid burden and memory loss. Furthermore, our hippocampal RNA-seq data, from young 2 × Tg-AD mice, were enriched with aberrantly expressed lncRNAs and miRNAs that are modulated by Tet2. Tet2-modulated lncRNAs (Malat1, Meg3, Sox2ot, Gm15477, Snhg1) and miRNAs (miR-764, miR-211, and miR-34a) may play a role in neuron formation. Overall, these results indicate that Tet2 may be a potential therapeutic target for repairing neuronal damage and cognitive impairment in AD.

TET2 promotor methylation and TET2 protein expression in pediatric posterior fossa ependymoma.

Pediatric posterior fossa ependymoma (PF) is one of the most common brain tumors in children. Recently, two subtypes of PF were identified. PF-A has a dismal prognosis and shows a hypermethylation phenotype, whereas PF-B shows a great genomic instability. The ten-eleven translocation methylcytosine dioxygenase 2 (TET2) gene (TET2) has been linked to the regulation of DNA methylation. We analyzed TET2 promotor methylation and protein expression to assess the role of TET2 in PF. Medical records of all PF cases treated in our institution between 1993 and 2015 were evaluated regarding tumor histology, grade, tumor location, gender, age, tumor recurrence, distant metastasis, survival and time to progression. Subsequently, we analyzed TET2 promotor methylation using methylation-specific polymerase chain reaction. TET2 protein expression was assessed using immunohistochemistry. Low TET2 expression was detected in seven of 17 cases. There was an association between low TET2 expression and tumor recurrence (P = 0.049). A TET2 promotor methylation was detected in five of 10 cases. There was no association between the TET2 promotor methylation with recurrence, tumor grade or gender. TET2 promotor methylation and low TET2 expression was detected in a subgroup of PF. Our data show an association between low TET2 expression and tumor recurrence in PF.

GBX2 Methylation Is a Novel Prognostic Biomarker and Improves Prediction of Biochemical Recurrence Among Patients with Prostate Cancer Negative for Intraductal Carcinoma and Cribriform Architecture.

BACKGROUND: Tumor intraductal carcinoma/cribriform architecture (IDC/C) is associated with an unfavorable prognosis and biochemical recurrence (BCR) in prostate cancer (PCa). Up to 70% of PCa patients are IDC/C-negative, but it is estimated that 20% of these cases still experience BCR. Thus, biomarkers for better detection of aggressive disease in IDC/C-negative patients are required. OBJECTIVE: To investigate tumor-specific methylation of the transcription factor GBX2 as a novel prognosticator and predictor of BCR in PCa patients stratified by histopathologic features including IDC/C. DESIGN, SETTING, AND PARTICIPANTS: Using genome-wide methylome profiling, we identified higher GBX2 methylation in grade group (GG) 4 tumors compared to GG1 (discovery cohort). The prognostic nature of GBX2 methylation was validated in silico using The Cancer Genome Atlas data (n=478) and a quantitative methylation assay for radical prostatectomy samples (n=254). Regulation of GBX2 methylation was investigated in prostate cells using methyl-CpG-binding domain sequencing and methylation analysis in functional knockouts of TET2, a key epigenetic player in prostate carcinogenesis. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The association of GBX2 methylation with Gleason score (GS), pathologic stage (pT), IDC/C, and BCR was analyzed using Kruskal-Wallis and Mann-Whitney tests. Univariate and multivariate Cox regression analyses were used to predict BCR. RESULTS: GBX2 methylation was associated with GS (p<0.05), pT (p<0.01), and BCR (p<0.05). GBX2 methylation (p=0.004), GS (p<0.001), pT (p=0.012), and prostate-specific antigen (p=0.005) were independent predictors of BCR. Among IDC/C-negative patients, GBX2 methylation improved prediction of BCR (p=0.002). Loss of TET2 in prostate cells resulted in greater GBX2 methylation. CONCLUSIONS: We identified GBX2 methylation as a novel prognostic factor in PCa and an independent predictor of BCR. We demonstrated the additive value of GBX2 methylation in predicting BCR among IDC/C-negative patients and elucidated a novel TET2-mediated upstream epigenetic regulatory mechanism of GBX2. PATIENT SUMMARY: We identified GBX2 methylation as a promising prognostic biomarker that could improve the identification of prostate cancer patients at higher risk of biochemical recurrence.