TET1 Depletion Induces Aberrant CpG Methylation in Colorectal Cancer Cells

Kai, Masahiro; Niinuma, Takeshi; Kitajima, Hiroshi; Yamamoto, Eiko; Harada, Taku; Aoki, Hironori; Maruyama, Reo; Toyota, Mutsumi; Sasaki, Yasushi; Sugai, Tamotsu; Tokino, Takashi; Nakase, Hiroshi; Suzuki, Hiromu

doi:10.1371/journal.pone.0168281

Cited by 14 publications

(14 citation statements)

References 53 publications

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“…This is supported by the fact that in gastric cancer cells, TET1 binds to the hypermethylated PTEN and re-activates its transcription through the demethylation of its promoter (45). Furthermore, it has been suggested that the decreased expression of TET1 may induce aberrant DNA methylation (46). Indeed, we observed an increase in the level of methylation at the +27 CpG site.…”

Section: Discussionsupporting

confidence: 68%

Curcumin induces re‑expression of BRCA1 and suppression of γ synuclein by modulating DNA promoter methylation in breast cancer cell lines

et al. 2020

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Restoration of normal DNA promoter methylation and expression states of cancer-related genes may be an option for the prevention as well as the treatment of several types of cancer. Constitutional promoter methylation of BRCA1 DNA repair associated (BRCA1) gene is linked with a high risk of developing breast and ovarian cancer. Furthermore, hypomethylation of the proto-oncogene γ synuclein (SNCG) is associated with the metastasis of breast and ovarian cancer and reduced disease-free survival (DFS). In the present study, we evaluated the potential of curcumin to re-express hypermethylated BRCA1 and to suppress hypomethylated SNCG in triple-negative breast cancer (TNBC) cell line HCC-38, the estrogen receptor-negative/progesterone receptor-negative (ER-/PR-) cell line UACC-3199, and the ER + /PR + cell line T47D. The cells were treated with 5 and 10 µM curcumin for 6 days and with 5-aza-2'-deoxycytidine (5'-aza-CdR) for 48 h. Methylation-specific PCR and bisulfite pyrosequencing assays were used to assess DNA promoter methylation while gene expression levels were analyzed using quantitative real-time PCR and immunoblotting. We found that curcumin treatment restored BRCA1 gene expression by reducing the DNA promoter methylation level in HCC-38 and UACC-3199 cells and that it suppressed the expression of SNCG by inducing DNA promoter methylation in T47D cells. Notably, 5'-aza-CdR restored BRCA1 gene expression only in UACC-3199, and not in HCC-38 cells. Curcumin-induced hypomethylation of the BRCA1 promoter appears to be realized through the upregulation of the ten-eleven translocation 1 (TET1) gene, whereas curcumin-induced hypermethylation of SNCG may be realized through the upregulation of the DNA methyltransferase 3 (DNMT3) and the downregulation of TET1. Notably, miR-29b was found to be reversely expressed compared to TET1 in curcumin-and 5'-aza-CdR-treated cells, suggesting its involvement in the regulation of TET1. Overall, our results indicate that curcumin has an intrinsic dual function on DNA promoter methylation. We believe that curcumin may be considered a promising therapeutic option for treating TNBC patients in addition to preventing breast and ovarian cancer, particularly in cancer-free females harboring methylated BRCA1.

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Section: Discussionsupporting

confidence: 68%

Curcumin induces re‑expression of BRCA1 and suppression of γ synuclein by modulating DNA promoter methylation in breast cancer cell lines

et al. 2020

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“…Genome wide DNA methylation was analyzed using an Infinium HumanMethylation450 BeadChip (Illumina, San Diego, CA, USA) as described [ 46 ]. The data were then assembled using GenomeStudio methylation software (Illumina) and analyzed using Microsoft Excel (Microsoft Corporation, Redmond, WA, USA) and JMP 11 (SAS Institute Inc., Cary, NC, USA).…”

Section: Methodsmentioning

confidence: 99%

Epigenetic silencing ofSMOC1in traditional serrated adenoma and colorectal cancer

et al. 2017

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Colorectal sessile serrated adenoma/polyps (SSA/Ps) are well-known precursors of colorectal cancer (CRC) characterized by BRAF mutation and microsatellite instability. By contrast, the molecular characteristics of traditional serrated adenoma (TSAs) are not fully understood. We analyzed genome-wide DNA methylation in TSAs having both protruding and flat components. We identified 11 genes, including SMOC1, methylation of which progressively increased during the development of TSAs. SMOC1 was prevalently methylated in TSAs, but was rarely methylated in SSA/Ps (p < 0.001). RT-PCR and immunohistochemistry revealed that SMOC1 was expressed in normal colon and SSA/Ps, but its expression was decreased in TSAs. Ectopic expression of SMOC1 suppressed proliferation, colony formation and in vivo tumor formation by CRC cells. Analysis of colorectal lesions (n = 847) revealed that SMOC1 is frequently methylated in TSAs, high-grade adenomas and CRCs. Among these, SMOC1 methylation was strongly associated with KRAS mutation and CpG island methylator phenotype (CIMP)-low. These results demonstrate that epigenetic silencing of SMOC1 is associated with TSA development but is rarely observed in SSA/Ps. SMOC1 expression could thus be a diagnostic marker of serrated lesions, and SMOC1 methylation could play a role in neoplastic pathways in TSAs and conventional adenomas.

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“…CRC cell lines (CaCO2, Colo320, DLD1, HCT116, HT29, LoVo, RKO, SW48, SW480, SW620, T84, and WiDr), a breast cancer cell line (MCF7), and HEK293 cells were described previously [54–56]. DLD1, RKO, MCF7, and HEK293 cells were maintained in DMEM supplemented with 10% fetal bovine serum.…”

Section: Methodsmentioning

confidence: 99%

“…Dot blot analysis was performed as described previously [56]. A mouse anti-5-methylcytosine (5-mC) monoclonal antibody (1:1000 dilution, catalog no 39649, Active Motif, Carlsbad, CA, USA) was used.…”

Section: Methodsmentioning

confidence: 99%

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UHRF1 depletion and HDAC inhibition reactivate epigenetically silenced genes in colorectal cancer cells

et al. 2019

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Background Ubiquitin-like protein containing PHD and RING finger domains 1 (UHRF1) is a major regulator of epigenetic mechanisms and is overexpressed in various human malignancies. In this study, we examined the involvement of UHRF1 in aberrant DNA methylation and gene silencing in colorectal cancer (CRC). Results CRC cell lines were transiently transfected with siRNAs targeting UHRF1 , after which DNA methylation was analyzed using dot blots, bisulfite pyrosequencing, and Infinium HumanMethylation450 BeadChip assays. Gene expression was analyzed using RT-PCR and gene expression microarrays. Depletion of UHRF1 rapidly induced genome-wide DNA demethylation in CRC cells. Infinium BeadChip assays and bisulfite pyrosequencing revealed significant demethylation across entire genomic regions, including CpG islands, gene bodies, intergenic regions, and repetitive elements. Despite the substantial demethylation, however, UHRF1 depletion only minimally reversed CpG island hypermethylation-associated gene silencing. By contrast, the combination of UHRF1 depletion and histone deacetylase (HDAC) inhibition reactivated the silenced genes and strongly suppressed CRC cell proliferation. The combination of UHRF1 depletion and HDAC inhibition also induced marked changes in the gene expression profiles such that cell cycle-related genes were strikingly downregulated. Conclusions Our results suggest that (i) maintenance of DNA methylation in CRC cells is highly dependent on UHRF1; (ii) UHRF1 depletion rapidly induces DNA demethylation, though it is insufficient to fully reactivate the silenced genes; and (iii) dual targeting of UHRF1 and HDAC may be an effective new therapeutic strategy. Electronic supplementary material The online version of this article (10.1186/s13148-019-0668-3) contains supplementary material, which is available to authorized users.

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TET1 Depletion Induces Aberrant CpG Methylation in Colorectal Cancer Cells

Cited by 14 publications

References 53 publications

Curcumin induces re‑expression of BRCA1 and suppression of γ synuclein by modulating DNA promoter methylation in breast cancer cell lines

Curcumin induces re‑expression of BRCA1 and suppression of γ synuclein by modulating DNA promoter methylation in breast cancer cell lines

Epigenetic silencing ofSMOC1in traditional serrated adenoma and colorectal cancer

UHRF1 depletion and HDAC inhibition reactivate epigenetically silenced genes in colorectal cancer cells

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