The impact of p53 function on the metabolic activation of the carcinogenic air pollutant 3-nitrobenzanthrone and its metabolites 3-aminobenzanthrone and N-hydroxy-3-aminobenzanthrone in human cells

Abstract

The tumour suppressor p53, encoded by TP53, is a key player in a wide network of signalling pathways. We investigated its role in the bioactivation of the environmental carcinogen 3-nitrobenzanthrone (3-NBA)found in diesel exhaust and its metabolites 3-aminobenzanthrone (3-ABA) and N-hydroxy-3-aminobenzanthrone (N-OH-3-ABA) in a panel of isogenic human colorectal HCT116 cells differing only with respect to their TP53 status [i.e. TP53(+/+), TP53(+/−), TP53(−/−), TP53(R248W/+) or TP53(R248W/−)]. As a measure of metabolic competence, DNA adduct formation was determined using 32P-postlabelling. Wild-type (WT) p53 did not affect the bioactivation of 3-NBA; no difference in DNA adduct formation was observed in TP53(+/+), TP53(+/−) and TP53(−/−) cells. Bioactivation of both metabolites 3-ABA and N-OH-3-ABA on the other hand was WT-TP53 dependent. Lower 3-ABA- and N-OH-3-ABA-DNA adduct levels were found in TP53(+/−) and TP53(−/−) cells compared to TP53(+/+) cells, and p53’s impact was attributed to differences in cytochrome P450 (CYP) 1A1 expression for 3-ABA whereas for N-OH-3-ABA, an impact of this tumour suppressor on sulphotransferase (SULT) 1A1/3 expression was detected. Mutant R248W-p53 protein function was similar to or exceeded the ability of WT-p53 in activating 3-NBA and its metabolites, measured as DNA adducts. However, identification of the xenobiotic-metabolising enzyme(s) (XMEs), through which mutant-p53 regulates these responses, proved difficult to decipher. For example, although both mutant cell lines exhibited higher CYP1A1 induction after 3-NBA treatment compared to TP53(+/+) cells, 3-NBA-derived DNA adduct levels were only higher in TP53(R248W/−) cells but not in TP53(R248W/+) cells. Our results show that p53’s influence on carcinogen activation depends on the agent studied and thereby on the XMEs that mediate the bioactivation of that particular compound. The phenomenon of p53 regulating CYP1A1 expression in human cells is consistent with other recent findings; however, this is the first study highlighting the impact of p53 on sulphotransferase-mediated (i.e. SULT1A1) carcinogen metabolism in human cells.

Impact of p53 function on the sulfotransferase‐mediated bioactivation of the alkylated polycyclic aromatic hydrocarbon 1‐hydroxymethylpyrene in vitro

“…Previous studies in HCT116 cells have investigated the impact of p53 on the metabolic activation of several PAHs (e.g., BaP, dibenz[a,h]anthracene [DBA], dibenzo[a,l] pyrene [DBP]) and some nitroarenes (e.g., 3-NBA and aristolochic acid I) Simoes et al 2008;Wohak et al 2016;Wohak et al 2018). A study of 3-NBA and its metabolites 3-ABA and N-OH-3-ABA included investigations of SULTs, because the genotoxicity of 3-NBA is strongly enhanced by SULT1A1 and SULT1A2 (Arlt et al 2017).…”

“…In addition to the role of p53 in DNA damage response, new functions are still being discovered. Over recent years, a role for p53 in modulating carcinogen metabolism has emerged Simoes et al 2008;Krais et al 2016a;Krais et al 2016b;Wohak et al 2016;Willis et al 2018;Wohak et al 2018). We have shown that DNA adduct formation by BaP was significantly impacted by p53 function both in vitro and in vivo and that the observed DNA damage correlates with CYP1A1 expression (Krais et al 2016a;Wohak et al 2016).…”

“…Cells were grown as adherent monolayers as described (Wohak et al 2016;Wohak et al 2018). Cells were grown as adherent monolayers as described (Wohak et al 2016;Wohak et al 2018).…”

“…Human colorectal HCT116 TP53(+/+), TP53(+/−), and TP53(−/−) cells were kindly provided by Prof. Bert Vogelstein, Johns Hopkins University School of Medicine, Baltimore, MD. Cells were grown as adherent monolayers as described (Wohak et al 2016;Wohak et al 2018). For treatment, cells were seeded at 3 × 10 4 cells/cm 2 , grown for 48 hr, and subsequently treated for up to 48 hr with 0, 1, 10, or 20 μM 1-HMP dissolved in dimethyl sulfoxide (DMSO; 0.5% final volume of medium).…”

“…p53 can be induced by multiple forms of cellular stress (e.g., DNA damage) and it functions at the crossroads of a network of signaling pathways that are crucial for regulating cell growth and apoptosis. Over recent years, a role for p53 in modulating carcinogen metabolism has emerged Simoes et al 2008;Krais et al 2016a;Krais et al 2016b;Wohak et al 2016;Willis et al 2018;Wohak et al 2018). Disruption of the normal p53 response by TP53 mutation leads to the development of tumors and various carcinogens have been associated with characteristic mutational signatures (Kucab et al 2015).…”