JBIC Journal of Biological Inorganic Chemistry

, Volume 10, Issue 2, pp 105–118

Time-dependent uptake, distribution and biotransformation of chromium(VI) in individual and bulk human lung cells: application of synchrotron radiation techniques

  • Hugh H. Harris
  • Aviva Levina
  • Carolyn T. Dillon
  • Irma Mulyani
  • Barry Lai
  • Zhonghou Cai
  • Peter A. Lay
Original Article

DOI: 10.1007/s00775-004-0617-1

Cite this article as:
Harris, H.H., Levina, A., Dillon, C.T. et al. J Biol Inorg Chem (2005) 10: 105. doi:10.1007/s00775-004-0617-1

Abstract

Chromium(VI) is a human carcinogen, primarily affecting the respiratory tract probably via active transport into cells, followed by the reduction to Cr(III) with the formation of DNA-damaging intermediates. Distribution of Cr and endogenous elements within A549 human lung adenocarcinoma epithelial cells, following treatment with Cr(VI) (100 μM, 20 min or 4 h) were studied by synchrotron-radiation-induced X-ray emission (SRIXE) of single freeze-dried cells. After the 20-min treatment, Cr was confined to a small area of the cytoplasm and strongly co-localized with S, Cl, K, and Ca. After the 4-h treatment, Cr was distributed throughout the cell, with higher concentrations in the nucleus and the cytoplasmic membrane. This time-dependence corresponded to ~100% or 0% clonogenic survival of the cells following the 20-min or 4-h treatments, respectively, and could potentially be explained by a new cellular protective mechanism. Such processes may also be important in reducing the potential hazards of Cr(III) dietary supplements, for which there is emerging evidence that they exert their anti-diabetic effects via biological oxidation to Cr(VI). The predominance of Cr(III) was confirmed by micro-XANES spectroscopy of intracellular Cr hotspots. X-ray absorption spectroscopy (XANES and EXAFS, using freeze-dried cells after the 0–4-h treatments) was used to gain insight into the chemical structures of Cr(III) complexes formed during the intracellular reduction of Cr(VI). The polynuclear nature of such complexes (probably with a combination of carboxylato and hydroxo bridging groups and O-donor atoms of small peptides or proteins) was established by XAFS data analyses.

Keywords

ChromiumCancerHuman cellsSynchrotron-radiation-induced X-ray emissionX-ray absorption spectroscopy

Abbreviations

ANBF

Australian National Beamline Facility

APS

Advanced Photon Source

cys

Cysteinato(2-)

DMEM

Dulbecco’s modified minimal essential medium

EPR

Electron paramagnetic resonance

EXAFS

Extended X-ray absorption fine structure

FT

Fourier-transform

GFAAS

Graphite-furnace atomic absorption spectroscopy

MS

Multiple scattering

PBS

Phosphate buffered saline

pic

Picolinato(1-) = 2-pyridinecarboxylato(1-)

SRIXE

Synchrotron-radiation-induced X-ray emission

SS

Single scattering

XANES

X-ray absorption near-edge structure

XAFS

X-ray absorption fine structure

XAS

X-ray absorption spectroscopy

Supplementary material

775_2004_617_ESM_supp.pdf (1.8 mb)
(PDF 1.8 MB)

Copyright information

© SBIC 2005

Authors and Affiliations

  • Hugh H. Harris
    • 1
  • Aviva Levina
    • 1
  • Carolyn T. Dillon
    • 1
    • 2
  • Irma Mulyani
    • 1
  • Barry Lai
    • 3
  • Zhonghou Cai
    • 3
  • Peter A. Lay
    • 1
  1. 1.Centre for Heavy Metals Research, and Centre for Structural Biology and Structural Chemistry, School of ChemistryUniversity of SydneySydneyAustralia
  2. 2.Australian Key Centre for Microscopy and Microanalysis, Electron Microscope Unit, Madsen BuildingUniversity of SydneySydneyAustralia
  3. 3.Experimental Facilities DivisionArgonne National LaboratoryArgonneUSA