Persistence of DNA damage following exposure of human bladder cells to chronic monomethylarsonous acid

S. M. Wnek, M. K. Medeiros, K. E. Eblin, A. J. Gandolfi

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Malignant transformation was demonstrated in UROtsa cells following 52-weeks of exposure to 50 nM monomethylarsonous acid (MMAIII); the result was the malignantly transformed cell line, URO-MSC. URO-MSC cells were used to study the induction of DNA damage and the alteration of DNA repair enzymes in both the presence of MMAIII [URO-MSC(+)] and after subsequent removal of MMAIII [URO-MSC(-)] following chronic, low-level exposure. In the presence of MMAIII, URO-MSC(+) cells demonstrated a sustained increase in DNA damage following 12-weeks of exposure; in particular, a significant increase in DNA single-strand breaks at 12-weeks of exposure consistently elevated through 52 weeks. The persistence of DNA damage in URO-MSC cells was assessed after a 2-week removal of MMAIII. URO-MSC(-) cells demonstrated a decrease in DNA damage compared to URO-MSC(+); however, DNA damage in URO-MSC(-) remained significantly elevated when compared to untreated UROtsa and increased in a time-dependent manner. Reactive oxygen species (ROS) were demonstrated to be a critical component in the generation of DNA damage determined through the incubation of ROS scavengers with URO-MSC cells. Poly (ADP-ribose) polymerase (PARP) is a key repair enzyme in DNA single-strand break repair. URO-MSC(+) resulted in a slight increase in PARP activity after 36-weeks of MMAIII exposure, suggesting the presence of MMAIII is inhibiting the increase in PARP activity. In support, PARP activity in URO-MSC(-) increased significantly, coinciding with a subsequent decrease in DNA damage demonstrated in URO-MSC(-) compared to URO-MSC(+). These data demonstrate that chronic, low-level exposure of UROtsa cells to 50 nM MMAIII results in: the induction of DNA damage that remains elevated upon removal of MMAIII; increased levels of ROS that play a role in MMAIII induced-DNA damage; and decreased PARP activity in the presence of MMAIII.

Original languageEnglish (US)
Pages (from-to)202-209
Number of pages8
JournalToxicology and Applied Pharmacology
Volume241
Issue number2
DOIs
StatePublished - Dec 1 2009

Keywords

  • Arsenic
  • Bladder cancer
  • DNA damage
  • Monomethylarsonous acid
  • UROtsa

ASJC Scopus subject areas

  • Toxicology
  • Pharmacology

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