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Genome-Wide Analysis of DNA Methylation in Gastrointestinal Cancer
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Genome-Wide Analysis of DNA Methylation in Gastrointestinal Cancer

Published on: September 18, 2020

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High-density array analysis of DNA methylation in Tamoxifen-resistant breast cancer cell lines

Kristin E Williams1, Douglas L Anderton2, Maxwell P Lee3

  • 1Molecular & Cellular Biology Graduate Program; Department of Veterinary & Animal Sciences; University of Massachusetts; Amherst, MA USA.

Epigenetics
|November 15, 2013
PubMed

Insights

Tamoxifen resistance in breast cancer may involve DNA methylation changes. Aberrant methylation in genes like ZNF350 and MAGED1 offers potential therapeutic targets, but responses vary, necessitating predictive biomarkers.

Area of Science:

  • Oncology
  • Epigenetics
  • Genomics

Background:

  • Estrogen receptor-alpha (ERα)-positive breast cancers, about two-thirds of all cases, are often treated with Tamoxifen.
  • Tamoxifen resistance develops in approximately 33% of patients after 5 years of treatment.
  • Aberrant DNA methylation, an epigenetic mechanism, is implicated in Tamoxifen resistance.

Purpose of the Study:

  • To understand Tamoxifen resistance mechanisms.
  • To identify novel pathways and targets of aberrant DNA methylation.
  • To analyze methylation patterns in Tamoxifen-resistant breast cancer cells.

Main Methods:

  • DNA methylation analysis using Illumina HumanMethylation450 BeadChip.
  • Comparison of methylation profiles between MCF-7, TMX2-11, and TMX2-28 breast cancer cell lines.
  • Investigation of ZNF350 and MAGED1 gene methylation and expression following 5-aza-2ꞌdeoxycitidine treatment.

Main Results:

  • Tamoxifen-resistant cell lines TMX2-11 and TMX2-28 showed thousands of differentially methylated CpG sites compared to MCF-7.
  • Shared hypermethylated (3000) and hypomethylated (200) CpGs were identified in both resistant cell lines.
  • 5-aza-2ꞌdeoxycitidine reduced promoter methylation and increased ZNF350 and MAGED1 expression in TMX2-28, but not TMX2-11.

Conclusions:

  • Aberrant DNA methylation plays a role in Tamoxifen resistance.
  • ZNF350 and MAGED1 are potential targets for methylation-based therapies.
  • Variable responses to methylation-targeted therapies underscore the need for predictive biomarkers in breast cancer treatment.
Keywords:
Breast CancerEstrogen ReceptorHumanMethylation450 BeadChipMAGED1Tamoxifen ResistanceZNF350methylation

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