Leukemogenic AML1-ETO fusion protein increases carcinogen-DNA adduct formation with upregulated expression of cytochrome P450-1A1 gene.
OBJECTIVE
AML1-ETO fusion protein is a product of chromosome translocation t(8;21) frequently occurred in acute myeloid leukemia (AML), but its sole expression appears to fail to cause overt leukemia in vivo. In this study, we investigated whether AML1-ETO expression impinged on action of chemical carcinogens-DNA adduct formation.


METHODS
AML1-ETO fusion protein was conditionally induced in engineered U937-A/E 9/14/18 cells. The formation of polycyclic aromatic hydrocarbon (PAH)-DNA adducts and the expression of PAH-metabolizing enzymes cytochrome P450 (CYP) 1A1 and arylhydrocarbon receptor (AhR) were detected by Western blot and/or quantitative RT-PCR. Luciferase reporter system was used to detect the regulation of AML1-ETO on CYP1A1 transcription.


RESULTS
Our results showed that AML1-ETO induction significantly increased the formation of carcinogen benzopyrene-DNA adducts in leukemic cells. In line with the effect, we also found that AML1-ETO induction upregulated CYP1A1 expression, which was dependent on AML1-binding motif in the promotor of CYP1A1 gene. Additionally, AML1-ETO protein also increased AhR expression, a ligand-activated transcription factor that mediates PAHs-induced CYP1A1 gene expression.


CONCLUSIONS
These data, combined with its inhibitory effect on DNA repair as reported previously, propose that the presence of AML1-ETO increases the susceptibility of cells to chemical carcinogens, which favors the development of additional genetic alterations.
Xu
Min
M
Institute of Health Science, Shanghai Jiao-Tong University School of Medicine/Shanghai Institutes of Biological Sciences and School of Graduate, Chinese Academy of Sciences, Shanghai, China.
Li
Dao
D
Lu
Ying
Y
Chen
Guo-Qiang
GQ
D002273:Carcinogens / Q000633:toxicity*; D045744:Cell Line, Tumor; D050676:Core Binding Factor Alpha 2 Subunit / Q000235:genetics* / Q000378:metabolism; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics* / Q000378:metabolism; D018736:DNA Adducts; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism / Q000633:toxicity; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007938:Leukemia; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism / Q000633:toxicity; D000075142:RUNX1 Translocation Partner 1 Protein; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism / Q000633:toxicity; D020298:U937 Cells
D002273:Carcinogens; D050676:Core Binding Factor Alpha 2 Subunit; D018736:DNA Adducts; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D000075142:RUNX1 Translocation Partner 1 Protein; C493728:RUNX1 protein, human; C082222:RUNX1T1 protein, human; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D019363:Cytochrome P-450 CYP1A1