Enhanced constitutive invasion activity in human nontumorigenic keratinocytes exposed to a low level of barium for a long time

Nguyen D. Thang, Ichiro Yajima, Shoko Ohnuma, Nobutaka Ohgami, Mayuko Y. Kumasaka, Gaku Ichihara, Masashi Kato

Research output: Contribution to journalArticle

4 Citations (Scopus)


We have recently demonstrated that exposure to barium for a short time (≤4 days) and at a low level (5 μM = 687 μg/L) promotes invasion of human nontumorigenic HaCaT cells, which have characteristics similar to those of normal keratinocytes, suggesting that exposure to barium for a short time enhances malignant characteristics. Here we examined the effect of exposure to low level of barium for a long time, a condition mimicking the exposure to barium through well water, on malignant characteristics of HaCaT keratinocytes. Constitutive invasion activity, focal adhesion kinase (FAK) protein expression and activity, and matrix metalloproteinase 14 (MMP14) protein expression in primary cultured normal human epidermal keratinocytes, HaCaT keratinocytes, and HSC5 and A431 human squamous cell carcinoma cells were augmented following an increase in malignancy grade of the cells. Constitutive invasion activity, FAK phosphorylation, and MMP14 expression levels of HaCaT keratinocytes after treatment with 5 μM barium for 4 months were significantly higher than those of control untreated HaCaT keratinocytes. Taken together, our results suggest that exposure to a low level of barium for a long time enhances constitutive malignant characteristics of HaCaT keratinocytes via regulatory molecules (FAK and MMP14) for invasion.

Original languageEnglish
Pages (from-to)161-167
Number of pages7
JournalEnvironmental Toxicology
Issue number2
Publication statusPublished - 2015 Feb 1



  • Barium
  • Focal adhesion kinase
  • Invasion
  • Keratinocytes
  • Matrix metalloproteinase
  • Well water

ASJC Scopus subject areas

  • Toxicology
  • Management, Monitoring, Policy and Law
  • Health, Toxicology and Mutagenesis

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