Inhibition of organic anion transporter (OAT) activity by cigarette smoke condensate

Abstract

Cigarette smoke condensate (CSC) has previously been shown to impair activity and expression of hepatic drug transporters. In the present study, we provided evidence that CSC also hinders activity of organic anion transporters (OATs), notably expressed at the kidney level. CSC thus cis-inhibited OAT substrate uptake in OAT1- and OAT3-transfected HEK293 cells, in a concentration-dependent manner (IC=72.1μg/mL for OAT1 inhibition and IC=27.3μg/mL for OAT3 inhibition). By contrast, OAT4 as well as the renal organic cation transporter (OCT) 2 were less sensitive to the inhibitory effect of CSC (IC=351.5μg/mL and IC=226.2μg/mL, for inhibition of OAT4 and OCT2, respectively). OAT3 activity was further demonstrated to be blocked by some single chemicals present in cigarette smoke such as the heterocyclic amines AαC (IC=11.3μM) and PhIP (IC=1.9μM), whereas other major cigarette smoke components used at 100μM, like nicotine, the nitrosamine NNK and the polycyclic aromatic hydrocarbons benzo(a)pyrene and phenanthrene, were without effect. AαC and PhIP however failed to trans-stimulate activity of OAT3, suggesting that they were not substrates for this transporter. Taken together, these data establish OAT1 and OAT3 transporters as targets of cigarette smoke chemicals, which may contribute to smoking-associated pharmacokinetics alterations.

Inhibition of organic cation transporter (OCT) activities by carcinogenic heterocyclic aromatic amines

“…OATP1B1 activity was additionally reduced by 100 µM Trp-P-1 and 100 µM Trp-P-2, suggesting that organic anion transporters are also targeted by HAAs. The fact that Trp-P-2, as well as PhIP and AC, inhibited OAT3 activity (Sayyed et al, 2017), fully supports this conclusion. Whether OATP1B1 may transport some…”

“…Besides ABC efflux pumps, solute carrier (SLC) transporters, which mainly mediate drug uptake into cells through facilitated diffusion or secondary active transport (Giacomini et al, 2010), are presumed to also interact with HAAs. Indeed, PhIP and AαC have been shown to block activities of the renal organic anion transporter (OAT) 3 (SLC22A8), without probably being handled by this transporter (Sayyed et al, 2017); OAT3 activity is also inhibited by Trp-P-2, whereas PhIP blocks that of OAT1 (SLC22A6). Trp-P-1 and Trp-P-2 have additionally been postulated to be transported by the dopamine active transporter (DAT/SLC6A3) and the serotonin transporter (SERT/SLC6A4) (Hashimoto et al, 2002;Naoi et al, 1989).…”

“…SLC transporter activities were analyzed through determining intracellular accumulation of reference fluorescent or radiolabeled substrates of these SLC transporters at 37°C for 5 min (SLC transporter-overexpressing HEK293 cells) or 10 min (HepaRG cells), in the absence or presence of reference inhibitors or tested HAAs, as previously described (Chedik et al, 2017;Le Vee et al, 2015;Sayyed et al, 2017). The reference substrates were 10 µM ASP + (for OCTs), 28.6 µM [1-14 C] TEA (for OCT1 and MATEs) and 10 µM DCF (for OATP1B1).…”

“…The effects of two concentrations of HAAs, i.e., 10 µM and 100 µM, were investigated towards OCT1, OCT2 and OCT3 activities ( Figure 3); these two HAA concentrations were chosen because they are in the range of those previously used in vitro in various studies (Hashimoto et al, 2002;Naoi et al, 1989;Sayyed et al, 2017). When used at 10 µM, Trp-P-1, Trp-P-2 and harmane significantly reduced OCT1, OCT2 and OCT3 activity, whereas norharmane decreased only those of OCT1 and OCT2 and 7,8-diMeIQx those of OCT2 and OCT3.…”

Neonicotinoid pesticides poorly interact with human drug transporters

“…For trans ‐stimulation assays (performed for OCT2 and OAT3), unlabeled TEA and glutarate were used as reference trans ‐stimulating agents, as previously described . Cells were first incubated in the absence (control cells) or the presence of 2 mM unlabeled TEA (HEK‐OCT2 cells), 1 mM glutarate (HEK‐OAT3 cells) or 100 μM of tested neonicotinoids (HEK‐OCT2 and HEK‐OAT3 cells) for 60 min (HEK‐OCT2 cells) or 15 min (HEK‐OAT3 cells) at 37°C.…”