CpG hypermethylation of collagen type I alpha 2 contributes to proliferation and migration activity of human bladder cancer

Int J Oncol. 2009 Jun;34(6):1593-602. doi: 10.3892/ijo_00000289.


In our microarray screening of methylated genes in bladder cancer (BC), the collagen type 1 alpha 2 (COL1A2) gene was the most up-regulated among the 30,144 genes screened. We hypothesize that inactivation of the COL1A2 gene through CpG methylation contributes to proliferation and migration activity of human BC. We subjected a bladder cancer cell line (BOY) and 67 BC specimens and 10 normal bladder epitheliums (NBEs) to conventional or real-time methylation quantitative polymerase chain reaction (PCR) and to real-time reverse transcriptase (RT)-PCR. We also established a stable COL1A2 transfectant for evaluating cell proliferation and migration activity. After 5-aza-dC treatment, the expression levels of COL1A2 mRNA transcript markedly increased in BOY. Our cell proliferation assays consistently demonstrated growth inhibition in the COL1A2 transfectant compared with control and wild-type BOY cells (p<0.0001). Wound healing assays also showed significant wound healing inhibition in the COL1A2 transfectant compared to the counterparts (p=0.0016). We demonstrated by bisulfite DNA sequencing that the promoter hypermethylation of COL1A2 was a frequent event in clinical BCs. The methylation index of COL1A2 was significantly higher in the 67 BCs than in the 10 NBEs (p=0.0011). Conversely, COL1A2 mRNA transcript was significantly lower in the BCs than in the NBEs (p=0.0052). The mechanism of COL1A2 down-regulation in BC is through CpG hypermethylation of the promoter region. COL1A2 gene inactivation through CpG hypermethylation may contribute to proliferation and migration activity of BC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Azacitidine / analogs & derivatives
  • Azacitidine / pharmacology
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Cell Adhesion
  • Cell Movement*
  • Cell Proliferation*
  • Collagen / genetics*
  • Collagen / metabolism
  • Collagen Type I
  • CpG Islands / genetics*
  • DNA Methylation*
  • Decitabine
  • Down-Regulation
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Immunoblotting
  • Immunoenzyme Techniques
  • Male
  • Middle Aged
  • Oligonucleotide Array Sequence Analysis
  • Promoter Regions, Genetic
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / pathology*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tumor Cells, Cultured
  • Urinary Bladder / metabolism
  • Urinary Bladder / pathology
  • Urinary Bladder Neoplasms / genetics
  • Urinary Bladder Neoplasms / pathology*


  • Biomarkers, Tumor
  • Collagen Type I
  • RNA, Messenger
  • Decitabine
  • Collagen
  • Azacitidine