Inflammation-associated extracellular β-glucuronidase alters cellular responses to the chemical carcinogen benzo[a]pyrene.

Q Shi,V M Arlt,C Veith,F J Van Schooten,L Maas,G R Haenen,R W L Godschalk,E Moonen,Y Riffo Vasquez,D Spina

doi:10.1007/s00204-015-1593-7

Q Shi, V M Arlt + Show 8 more

Open Access

https://doi.org/10.1007/s00204-015-1593-7

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Abstract

Neutrophils infiltrate tissues during inflammation, and when activated, they release β-glucuronidase. Since inflammation is associated with carcinogenesis, we investigated how extracellular β-glucuronidase changed the in vitro cellular response to the chemical carcinogen benzo(a)pyrene (B[a]P). For this we exposed human liver (HepG2) and lung (A549) cells to B[a]P in the presence or absence of β-glucuronidase. β-Glucuronidase reduced B[a]P-induced expression of CYP1A1 and CYP1B1 at 6 h after exposure, which did not depend on β-glucuronidase activity, because the inhibitor d-saccharic acid 1,4-lactone monohydrate did not antagonize the effect of β-glucuronidase. On the other hand, the inhibitory effect of β-glucuronidase on CYP expression was dependent on signalling via the insulin-like growth factor receptor (IGF2R, a known receptor for β-glucuronidase), because co-incubation with the IGF2R inhibitor mannose-6-phosphate completely abolished the effect of β-glucuronidase. Extracellular β-glucuronidase also reduced the formation of several B[a]P metabolites and B[a]P–DNA adducts. Interestingly, at 24 h of exposure, β-glucuronidase significantly enhanced CYP expression, probably because β-glucuronidase de-glucuronidated B[a]P metabolites, which continued to trigger the aryl hydrocarbon receptor (Ah receptor) and induced expression of CYP1A1 (in both cell lines) and CYP1B1 (in A549 only). Consequently, significantly higher concentrations of B[a]P metabolites and DNA adducts were found in β-glucuronidase-treated cells at 24 h. DNA adduct levels peaked at 48 h in cells that were exposed to B[a]P and treated with β-glucuronidase. Overall, these data show that β-glucuronidase alters the cellular response to B[a]P and ultimately enhances B[a]P-induced DNA adduct levels.

Highlights

Chronic inflammation is causally associated with cancer development, and inflammation was considered as the seventh hallmark feature of cancer (Colotta et al 2009; Shacter and Weitzman 2002)
We studied the impact of extracellular β-glucuronidase on the formation of B[a]P metabolites (3-OH-B[a]P, B[a]P-9,10diol and B[a]P-7,8-diol), gene expression of some enzymes pivotal in B[a]P metabolism, and DNA adduct formation in human liver cell line (HepG2) and human lung cell line (A549)
cytochrome P450 isoforms 1A1 (CYP1A1) expression was still enhanced with additional M6P at 24 h, but the changes in expression were less pronounced. It remains to be established how the cellular response to B[a]P is affected by the presence of extracellular β-glucuronidase, which is released during inflammation

Summary

Introduction

Chronic inflammation is causally associated with cancer development, and inflammation was considered as the seventh hallmark feature of cancer (Colotta et al 2009; Shacter and Weitzman 2002). This is illustrated for instance by the relatively high incidence of lung cancer in chronic obstructive pulmonary disease (COPD) patients (Young et al 2009). It has been shown that under inflammatory conditions, PMN enhance the mutagenic potential of chemical carcinogens (Borm et al 1997; Van Schooten et al 2004). There is still little data available on other factors that are released by the relatively high number of PMN during chronic inflammation, including β-glucuronidase, and how these influence the cellular response to chemical carcinogens (Basinska and Florianczyk 2003)

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