The influence of ATM, ATR, DNA-PK inhibitors on the cytotoxic and genotoxic effects of dibenzo[def,p]chrysene on human hepatocellular cancer cell line HepG2.
The effect of inhibitors of phosphatidylinositol-3-kinase related kinases (PIKK): ataxia-telangiectasia mutated (ATM), ATM- and Rad3-related (ATR) and DNA-dependent protein kinase (DNA-PK) on the response of HepG2 human liver cancer cells to dibenzo[def,p]chrysene (DBC) was investigated. High cytotoxicity of DBC (IC50=0.1μM) was observed after 72h incubation. PIKK inhibitors: KU55933 (5μM), NU7026 (10μM) or caffeine (1 and 2mM) when used alone did not significantly influence the cytotoxicity. However, two combinations: KU55933/NU7026 and caffeine/NU7026 significantly increased HepG2 viability (by 25%) after treatment with DBC at 0.5μM. The cytoprotective effect was confirmed by cell cycle and apoptosis/necrosis analysis. DNA damage level after exposure to DBC assessed by comet assay (single strand breaks) showed a long persistence and significant decrease after incubation of the cells in the presence the inhibitors (the combination of KU55933+NU7026 showed the strongest effect). Weak induction of reactive oxygen species (ROS) by DBC (0.5μM) was observed. Although, KU55933 and NU7026 when used alone did not increase ROS levels in the cells, their combination induced the ROS increase and moderately enhanced ROS generation by DBC. We propose a mechanism how cells with damaged DNA after exposure to DBC and under the condition of PIKK inhibition, may be at higher risk of undergoing malignant transformation.
Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland. Electronic address: sgajda@imp.lodz.pl.
Sylwia
S
Spryszyńska
Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland. Electronic address: smok@imp.lodz.pl.
Anna
A
Smok-Pieniążek
Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland. Electronic address: mkomorow@imp.lodz.pl.
Magdalena
M
Ferlińska
Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland. Electronic address: joanna@imp.lodz.pl.
Joanna
J
Roszak
Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland. Electronic address: nocun@imp.lodz.pl.
Marek
M
Nocuń
Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland. Electronic address: mstep@imp.lodz.pl.
Maciej
M
Stępnik
D017209:Apoptosis / Q000187:drug effects; D064007:Ataxia Telangiectasia Mutated Proteins / Q000037:antagonists & inhibitors; D001580:Benzopyrenes / Q000633:toxicity*; D002110:Caffeine / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D003603:Cytotoxins / Q000633:toxicity*; D053904:DNA Breaks, Single-Stranded / Q000187:drug effects*; D051747:DNA-Activated Protein Kinase / Q000037:antagonists & inhibitors; D056945:Hep G2 Cells; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D009153:Mutagens / Q000633:toxicity*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011753:Pyrones / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism
C479235:2-(morpholin-4-yl)benzo(h)chromen-4-one; C495818:2-morpholin-4-yl-6-thianthren-1-yl-pyran-4-one; D001580:Benzopyrenes; D002867:Chromones; D003603:Cytotoxins; D009025:Morpholines; D009153:Mutagens; D047428:Protein Kinase Inhibitors; D011753:Pyrones; D017382:Reactive Oxygen Species; D002110:Caffeine; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D051747:DNA-Activated Protein Kinase; C041517:dibenzo(a,l)pyrene
DNA damage signaling; Dibenzo[def,p]chrysene; HepG2; PIKK inhibitors