Involvement of epigenetics and EMT-related miRNA in arsenic-induced neoplastic transformation and their potential clinical use

Cancer Prev Res (Phila). 2015 Mar;8(3):208-21. doi: 10.1158/1940-6207.CAPR-14-0251. Epub 2015 Jan 13.


Exposure to toxicants leads to cumulative molecular changes that overtime increase a subject's risk of developing urothelial carcinoma. To assess the impact of arsenic exposure at a time progressive manner, we developed and characterized a cell culture model and tested a panel of miRNAs in urine samples from arsenic-exposed subjects, urothelial carcinoma patients, and controls. To prepare an in vitro model, we chronically exposed an immortalized normal human bladder cell line (HUC1) to arsenic. Growth of the HUC1 cells was increased in a time-dependent manner after arsenic treatment and cellular morphology was changed. In a soft agar assay, colonies were observed only in arsenic-treated cells, and the number of colonies gradually increased with longer periods of treatment. Similarly, invaded cells in an invasion assay were observed only in arsenic-treated cells. Withdrawal of arsenic treatment for 2.5 months did not reverse the tumorigenic properties of arsenic-treated cells. Western blot analysis demonstrated decreased PTEN and increased AKT and mTOR in arsenic-treated HUC1 cells. Levels of miR-200a, miR-200b, and miR-200c were downregulated in arsenic-exposed HUC1 cells by quantitative RT-PCR. Furthermore, in human urine, miR-200c and miR-205 were inversely associated with arsenic exposure (P = 0.005 and 0.009, respectively). Expression of miR-205 discriminated cancer cases from controls with high sensitivity and specificity (AUC = 0.845). Our study suggests that exposure to arsenic rapidly induces a multifaceted dedifferentiation program and miR-205 has potential to be used as a marker of arsenic exposure as well as a maker of early urothelial carcinoma detection.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Apoptosis
  • Arsenic / adverse effects*
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Blotting, Western
  • Case-Control Studies
  • Cell Movement
  • Cell Proliferation
  • Cell Transformation, Neoplastic / chemically induced
  • Cell Transformation, Neoplastic / genetics
  • Cell Transformation, Neoplastic / pathology*
  • Cells, Cultured
  • Cohort Studies
  • DNA Methylation
  • Epigenesis, Genetic / genetics*
  • Epithelial-Mesenchymal Transition*
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Immunoenzyme Techniques
  • Male
  • MicroRNAs / analysis*
  • MicroRNAs / genetics
  • Middle Aged
  • Neoplasm Invasiveness
  • PTEN Phosphohydrolase / genetics
  • PTEN Phosphohydrolase / metabolism
  • RNA, Messenger / genetics
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • TOR Serine-Threonine Kinases / genetics
  • TOR Serine-Threonine Kinases / metabolism
  • Urinary Bladder / drug effects
  • Urinary Bladder / metabolism
  • Urinary Bladder / pathology*
  • Urinary Bladder Neoplasms / drug therapy
  • Urinary Bladder Neoplasms / genetics
  • Urinary Bladder Neoplasms / pathology*
  • Young Adult


  • Biomarkers, Tumor
  • MicroRNAs
  • RNA, Messenger
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • PTEN Phosphohydrolase
  • PTEN protein, human
  • Arsenic