Tumour necrosis factor-α (TNF-α) enhances dietary carcinogen-induced DNA damage in colorectal cancer epithelial cells through activation of JNK signaling pathway
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Published version
Author(s)
Alotaibi, Aminah
Li, Jia
Gooderham, nigel
Type
Journal Article
Abstract
Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer death. Benzo[a]pyrene (BaP) and 2-amino-1-methyl-6-phenylimidazol [4,5-b] pyridine (PhIP) present in cooked meat are pro-carcinogens and considered to be potential risk factors for CRC. Their carcinogenic and mutagenic effects require metabolic activation primarily by cytochrome P450 1 family enzymes (CYPs); the expression of these enzymes can be modulated by aryl hydrocarbon receptor (AhR) activation and the tumour microenvironment, involving mediators of inflammation. In this study, we hypothesized that tumour necrosis factor-α (TNF-α), a key mediator of inflammation, modulates BaP- and PhIP-induced DNA damage in colon cancer epithelial cells. Importantly, we observed that TNF-α alone (0.1–100 pg/ml) induced DNA damage (micronuclei formation) in HCT-116 cells and co-treatment of TNF-α with BaP or PhIP showed higher levels of DNA damage compared to the individual single treatments. TNF-α alone or in combination with BaP or PhIP did not affect the expression levels of CYP1A1 and CYP1B1 (target genes of AhR signaling pathways). The DNA damage induced by TNF-α was elevated in p53 null HTC-116 cells compared to wild type cells, suggesting that TNF-α-induced DNA damage is suppressed by functional p53. In contrast, p53 status failed to affect BaP and PhIP induced micronucleus frequency. Furthermore, JNK and NF-κB signaling pathway were activated by TNF-α treatment but only inhibition of JNK significantly reduced TNF-α-induced DNA damage. Collectively, these findings suggest that TNF-α induced DNA damage involves JNK signaling pathway rather than AhR and NF-κB pathways in colon cancer epithelial cells.
Date Issued
2021-06-15
Date Acceptance
2021-04-30
Citation
Toxicology, 2021, 457
ISSN
0300-483X
Publisher
Elsevier
Journal / Book Title
Toxicology
Volume
457
Copyright Statement
© 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Sponsor
Medical Research Council (MRC)
Commission of the European Communities
Royal Embassy Of Saudi Arabia
Grant Number
MR/P002536/1
715662
NC268
Subjects
CYP1A1/1B1
Cytotoxicity
DNA damage
Genotoxicity
JNK pathway
TNF-α
1115 Pharmacology and Pharmaceutical Sciences
Toxicology
Publication Status
Published
Article Number
ARTN 152806
Date Publish Online
2021-05-04