TET2 is a component of the estrogen receptor complex and controls 5mC to 5hmC conversion at estrogen receptor cis-regulatory regions.
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ABSTRACT: Estrogen receptor-α (ER) drives tumor development in ER-positive (ER+) breast cancer. The transcription factor GATA3 has been closely linked to ER function, but its precise role in this setting remains unclear. Quantitative proteomics was used to assess changes to the ER complex in response to GATA3 depletion. Unexpectedly, few proteins were lost from the ER complex in the absence of GATA3, with the only major change being depletion of the dioxygenase TET2. TET2 binding constituted a near-total subset of ER binding in multiple breast cancer models, with loss of TET2 associated with reduced activation of proliferative pathways. TET2 knockdown did not appear to change global methylated cytosine (5mC) levels; however, oxidation of 5mC to 5-hydroxymethylcytosine (5hmC) was significantly reduced, and these events occurred at ER enhancers. These findings implicate TET2 in the maintenance of 5hmC at ER sites, providing a potential mechanism for TET2-mediated regulation of ER target genes.
Project description:Estrogen receptor-alpha (ER) drives tumour development and metastasis in ER positive (ER+) breast cancer. GATA3 is a transcription factor that has been closely linked to ER function, but the role of GATA3 in ER-transcriptional activity is not clear. We sought to identify the contribution of GATA3 to the ER complex, by conducting quantitative multiplexed rapid immunoprecipitation mass spectrometry of endogenous proteins (qPLEX-RIME), to assess changes to the ER complex in response to GATA3 depletion. Unexpectedly, very few proteins were dissociated from the ER complex in the absence of GATA3, with the only major change being loss of TET2 in the ER complex. In breast cancer cells and Patient-Derived Xenograft (PDX) tissue, TET2 binding events were shown to constitute a near-total subset of ER binding events, and loss of TET2 was functionally associated with reduced activation of proliferative pathways. To investigate the TET2-ER relationship, the role of TET2 in regulating DNA modifications in ER+ breast cancer cells was examined. TET2 knockdown did not appear to result in changes to global DNA methylation, however, oxidation of methylated DNA to 5-hydroxymethylcytosine (5hmC) was significantly reduced after TET2 depletion and these events occurred at ER enhancers. These findings implicate TET2 in the production and maintenance of 5hmC at ER sites, providing a potential mechanism for TET2-mediated regulation of ER target genes.
Project description:Estrogen receptor-a (ER) drives tumour development and metastasis in ER positive (ER+) breast cancer. GATA3 is a transcription factor that has been closely linked to ER function, but the role of GATA3 in ER transcriptional activity is not clear. We sought to identify the contribution of GATA3 to the ER complex by conducting quantitative multiplexed rapid immunoprecipitation mass spectrometry of endogenous proteins (qPLEX-RIME) to assess changes to the ER complex in response to GATA3 depletion. Unexpectedly, very few proteins were dissociated from the ER complex in the absence of GATA3, with the only major change being depletion of TET2 from the ER complex. In breast cancer cells and Patient-Derived Xenograft (PDX) tissue, TET2 binding events were shown to constitute a near-total subset of ER binding events, and loss of TET2 was functionally associated with reduced activation of proliferative pathways. To investigate the TET2-ER relationship, the role of TET2 in regulating DNA modifications in ER+ breast cancer cells was examined. TET2 knockdown did not appear to result in changes to global DNA methylation, however, oxidation of methylated DNA to 5-hydroxymethylcytosine (5hmC) was significantly reduced after TET2 depletion and these events occurred at ER enhancers. These findings implicate TET2 in the production and maintenance of 5hmC at ER sites, providing a potential mechanism for TET2-mediated regulation of ER target genes.
Project description:Estrogen receptor-a (ER) drives tumour development and metastasis in ER positive (ER+) breast cancer. GATA3 is a transcription factor that has been closely linked to ER function, but the role of GATA3 in ER transcriptional activity is not clear. We sought to identify the contribution of GATA3 to the ER complex by conducting quantitative multiplexed rapid immunoprecipitation mass spectrometry of endogenous proteins (qPLEX-RIME) to assess changes to the ER complex in response to GATA3 depletion. Unexpectedly, very few proteins were dissociated from the ER complex in the absence of GATA3, with the only major change being depletion of TET2 from the ER complex. In breast cancer cells and Patient-Derived Xenograft (PDX) tissue, TET2 binding events were shown to constitute a near-total subset of ER binding events, and loss of TET2 was functionally associated with reduced activation of proliferative pathways. To investigate the TET2-ER relationship, the role of TET2 in regulating DNA modifications in ER+ breast cancer cells was examined. TET2 knockdown did not appear to result in changes to global DNA methylation, however, oxidation of methylated DNA to 5-hydroxymethylcytosine (5hmC) was significantly reduced after TET2 depletion and these events occurred at ER enhancers. These findings implicate TET2 in the production and maintenance of 5hmC at ER sites, providing a potential mechanism for TET2-mediated regulation of ER target genes.
Project description:Estrogen receptor-a (ER) drives tumour development and metastasis in ER positive (ER+) breast cancer. GATA3 is a transcription factor that has been closely linked to ER function, but the role of GATA3 in ER transcriptional activity is not clear. We sought to identify the contribution of GATA3 to the ER complex by conducting quantitative multiplexed rapid immunoprecipitation mass spectrometry of endogenous proteins (qPLEX-RIME) to assess changes to the ER complex in response to GATA3 depletion. Unexpectedly, very few proteins were dissociated from the ER complex in the absence of GATA3, with the only major change being depletion of TET2 from the ER complex. In breast cancer cells and Patient-Derived Xenograft (PDX) tissue, TET2 binding events were shown to constitute a near-total subset of ER binding events, and loss of TET2 was functionally associated with reduced activation of proliferative pathways. To investigate the TET2-ER relationship, the role of TET2 in regulating DNA modifications in ER+ breast cancer cells was examined. TET2 knockdown did not appear to result in changes to global DNA methylation, however, oxidation of methylated DNA to 5-hydroxymethylcytosine (5hmC) was significantly reduced after TET2 depletion and these events occurred at ER enhancers. These findings implicate TET2 in the production and maintenance of 5hmC at ER sites, providing a potential mechanism for TET2-mediated regulation of ER target genes.
Project description:BackgroundThis study aimed to evaluate the correlations of 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC), and ten-eleven translocation enzyme 2 (TET2) expressions in lesion tissue with histological classification of breast precancerous lesion.MethodsEighty-three patients with breast ductal intraepithelial neoplasia (DIN), 20 patients with breast ductal carcinoma in situ with microinvasion (DCIS-MI), and 10 patients with invasive breast cancer were included. Histological classification of the DIN patients was classified as DIN1A, DIN1B, DIN1C, DIN2, and DIN3. 5mC, 5hmC, and TET2 expressions in lesion tissues from biopsy were assessed by immunohistochemistry (IHC) assay.Results5hmC and TET2 were negatively associated with histological classification as validated by both IHC score and IHC semi-quantification expression grades in total patients (all P < .05); however, no correlation of 5mC with histological classification was found (all P > .05). 5mC (P = .004) was negatively but 5hmC (P < .001) was positively correlated with TET2, while no association of 5mC with 5hmC was discovered in total patients (P = .078). In addition, 5mC was positively associated with ER expression in total patients (P = .040). In subgroups, 5mC was negatively correlated with 5hmC in DIN1C patients (P = .023) and invasive cancer patients (P = .044), and 5mC was negatively associated with TET2 in DIN1B patients (P = .004) as well as DCIS-MI patients (P = .003).Conclusion5hmC and TET2 have the potentials to serve as biomarkers that could assist in the identification of presence and progression of breast precancerous lesion.