TY - JOUR
T1 - In vitro profiling of epigenetic modifications underlying heavy metal toxicity of tungsten-alloy and its components
AU - Verma, Ranjana
AU - Xu, Xiufen
AU - Jaiswal, Manoj K.
AU - Olsen, Cara
AU - Mears, David
AU - Caretti, Giuseppina
AU - Galdzicki, Zygmunt
N1 - Funding Information:
The work presented here was supported in part by grants from Blast Spinal Cord Injury Research Program [ HU0001-07-2-0008 ], Defense Medical Research and Development Program [ NC706Z , NC706U], and Center for Neuroscience & Regenerative Medicine Program [ G1703O ], AIRC MFAG 5386 and Marie Curie IRG. This manuscript does not represent US government views.
Funding Information:
This work was supported by grants from the Blast Spinal Cord Injury Research Program [HU0001-07-2-0008], Defense Medical Research and Development Program [NC706Z, NC706U] (ZG & RV), Center for Neuroscience & Regenerative Medicine Program [G1703O] (ZG, RV and MKJ), AIRC MFAG 5386 (GC) and Marie Curie IRG (GC). Study sponsors had no involvement in the study design; collection, analysis and interpretation of data; the writing of the manuscript; the decision to submit the manuscript for publication.
PY - 2011/6/15
Y1 - 2011/6/15
N2 - Tungsten-alloy has carcinogenic potential as demonstrated by cancer development in rats with intramuscular implanted tungsten-alloy pellets. This suggests a potential involvement of epigenetic events previously implicated as environmental triggers of cancer. Here, we tested metal induced cytotoxicity and epigenetic modifications including H3 acetylation, H3-Ser10 phosphorylation and H3-K4 trimethylation. We exposed human embryonic kidney (HEK293), human neuroepithelioma (SKNMC), and mouse myoblast (C2C12) cultures for 1-day and hippocampal primary neuronal cultures for 1-week to 50-200μg/ml of tungsten-alloy (91% tungsten/6% nickel/3% cobalt), tungsten, nickel, and cobalt. We also examined the potential role of intracellular calcium in metal mediated histone modifications by addition of calcium channel blockers/chelators to the metal solutions. Tungsten and its alloy showed cytotoxicity at concentrations > 50 μg/ml, while we found significant toxicity with cobalt and nickel for most tested concentrations. Diverse cell-specific toxic effects were observed, with C2C12 being relatively resistant to tungsten-alloy mediated toxic impact. Tungsten-alloy, but not tungsten, caused almost complete dephosphorylation of H3-Ser10 in C2C12 and hippocampal primary neuronal cultures with H3-hypoacetylation in C2C12. Dramatic H3-Ser10 dephosphorylation was found in all cobalt treated cultures with a decrease in H3 pan-acetylation in C2C12, SKNMC and HEK293. Trimethylation of H3-K4 was not affected. Both tungsten-alloy and cobalt mediated H3-Ser10 dephosphorylation were reversed with BAPTA-AM, highlighting the role of intracellular calcium, confirmed with 2-photon calcium imaging. In summary, our results for the first time reveal epigenetic modifications triggered by tungsten-alloy exposure in C2C12 and hippocampal primary neuronal cultures suggesting the underlying synergistic effects of tungsten, nickel and cobalt mediated by changes in intracellular calcium homeostasis and buffering.
AB - Tungsten-alloy has carcinogenic potential as demonstrated by cancer development in rats with intramuscular implanted tungsten-alloy pellets. This suggests a potential involvement of epigenetic events previously implicated as environmental triggers of cancer. Here, we tested metal induced cytotoxicity and epigenetic modifications including H3 acetylation, H3-Ser10 phosphorylation and H3-K4 trimethylation. We exposed human embryonic kidney (HEK293), human neuroepithelioma (SKNMC), and mouse myoblast (C2C12) cultures for 1-day and hippocampal primary neuronal cultures for 1-week to 50-200μg/ml of tungsten-alloy (91% tungsten/6% nickel/3% cobalt), tungsten, nickel, and cobalt. We also examined the potential role of intracellular calcium in metal mediated histone modifications by addition of calcium channel blockers/chelators to the metal solutions. Tungsten and its alloy showed cytotoxicity at concentrations > 50 μg/ml, while we found significant toxicity with cobalt and nickel for most tested concentrations. Diverse cell-specific toxic effects were observed, with C2C12 being relatively resistant to tungsten-alloy mediated toxic impact. Tungsten-alloy, but not tungsten, caused almost complete dephosphorylation of H3-Ser10 in C2C12 and hippocampal primary neuronal cultures with H3-hypoacetylation in C2C12. Dramatic H3-Ser10 dephosphorylation was found in all cobalt treated cultures with a decrease in H3 pan-acetylation in C2C12, SKNMC and HEK293. Trimethylation of H3-K4 was not affected. Both tungsten-alloy and cobalt mediated H3-Ser10 dephosphorylation were reversed with BAPTA-AM, highlighting the role of intracellular calcium, confirmed with 2-photon calcium imaging. In summary, our results for the first time reveal epigenetic modifications triggered by tungsten-alloy exposure in C2C12 and hippocampal primary neuronal cultures suggesting the underlying synergistic effects of tungsten, nickel and cobalt mediated by changes in intracellular calcium homeostasis and buffering.
KW - 2-photon calcium imaging
KW - Calcium channel blockers
KW - Calcium chelators
KW - Cobalt
KW - Cytotoxicity
KW - Epigenetics
KW - H3-histone modifications
KW - Nickel
KW - Tungsten-alloy
UR - http://www.scopus.com/inward/record.url?scp=79956331766&partnerID=8YFLogxK
U2 - 10.1016/j.taap.2011.04.002
DO - 10.1016/j.taap.2011.04.002
M3 - Article
C2 - 21513724
AN - SCOPUS:79956331766
SN - 0041-008X
VL - 253
SP - 178
EP - 187
JO - Toxicology and Applied Pharmacology
JF - Toxicology and Applied Pharmacology
IS - 3
ER -