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Genome-Wide Analysis of DNA Methylation in Gastrointestinal Cancer
07:50

Genome-Wide Analysis of DNA Methylation in Gastrointestinal Cancer

Published on: September 18, 2020

Aberrant hypermethylation of miR-9 genes in gastric cancer

Kuo-Wang Tsai1, Yu-Lun Liao, Chew-Wun Wu

  • 1Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, China.

Epigenetics
|September 21, 2011
PubMed

Insights

Gastric cancer involves DNA methylation silencing tumor suppressive microRNAs (miRNAs), specifically miR-9. Reactivating miR-9 in stomach cancer cells inhibited proliferation, migration, and invasion, indicating its tumor-suppressive role.

Area of Science:

  • Oncology
  • Molecular Biology
  • Epigenetics

Background:

  • Gastric cancer development involves genetic and epigenetic alterations.
  • Tumor suppressive microRNAs (miRNAs) are frequently deregulated in cancer via aberrant DNA methylation.
  • Gastric cancer progression is linked to epigenetic silencing of key regulatory genes.

Purpose of the Study:

  • To investigate the role of miR-9 methylation in gastric cancer.
  • To determine if miR-9 acts as a tumor suppressor in gastric cancer.
  • To analyze the methylation status and expression of miR-9 genes in gastric cancer cells and tissues.

Main Methods:

  • Analysis of DNA methylation patterns at miR-9 loci (miR-9-1, miR-9-2, miR-9-3) in gastric cancer cells.
  • Treatment of gastric cancer cells with 5-Aza-dC to assess reactivation of miR-9 genes.
  • Quantitative analysis of miR-9 expression levels in gastric cancer tissues versus normal adjacent tissues.
  • Assessment of miR-9's functional role by ectopic expression in gastric cancer cells.

Main Results:

  • Three independent miR-9 genetic loci (miR-9-1, miR-9-2, miR-9-3) showed simultaneous DNA methylation in gastric cancer cells.
  • DNA methylation-mediated silencing of miR-9 genes was reversible with 5-Aza-dC treatment.
  • miR-9 expression was significantly down-regulated in gastric cancers compared to normal tissues.
  • A tumor-specific DNA methylation pattern for miR-9 genes was observed in 72 primary gastric cancer specimens.
  • Ectopic expression of miR-9 suppressed gastric cancer cell proliferation, migration, and invasion.

Conclusions:

  • Aberrant DNA methylation simultaneously silences multiple miR-9 genes in gastric cancer.
  • miR-9 functions as a tumor suppressor in gastric cancer, inhibiting key malignant behaviors.
  • Restoring miR-9 expression may represent a therapeutic strategy for gastric cancer.

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