Biphasic modulation of cAMP levels by the contraceptive nomegestrol acetate. Impact on P-glycoprotein expression and activity in hepatic cells

Abstract

ABC transporters are key players in drug excretion with alterations in their expression and activity by therapeutic agents potentially leading to drug-drug interactions. The interaction potential of nomegestrol acetate (NMGA), a synthetic progestogen increasingly used as oral contraceptive, had never been explored. In this work we evaluated (1) the effect of NMGA on ABC transporters in the human hepatic cell line HepG2 and (2) the underlying molecular mechanism. NMGA (5, 50 and 500 nM) increased P-glycoprotein (P-gp) expression at both protein and mRNA levels and reduced intracellular calcein accumulation, indicating an increase also in transporter activity. This up-regulation of P-gp was corroborated in Huh7 cells and was independent of the classical progesterone receptor. Instead, using a siRNA-mediated silencing approach, we demonstrated the involvement of membrane progesterone receptor α. Moreover, we found that the activation of this receptor by NMGA led to a falling-rising profile in intracellular cAMP levels and protein kinase A activity over time, ultimately leading to transcriptional P-gp up-regulation. Finally, we identified inhibitory G protein and phosphodiesterases as mediators of this novel biphasic modulation. These results demonstrate the ability of NMGA to selectively up-regulate hepatic P-gp expression and activity and constitute the first report of ABC transporter modulation by membrane progesterone receptor α. If a similar regulation took place in vivo, decreased bioavailability and therapeutic efficacy of NMGA-coadministered P-gp substrates could be expected. This holds special importance considering long-term administration of NMGA and broad substrate specificity of P-gp.

Intraluminal nutrients acutely strengthen rat intestinal MRP2 barrier function by a glucagon‐like peptide‐2‐mediated mechanism

“…Then, they were incubated with culture medium alone (control group) or culture medium containing 50 µM adenosine (adenosine group) for 15 minutes. Immediately afterwards, cells were washed with PBS and lysed in HCl (0.1 M, 20 min) at room temperature in order to stop phosphodiesterase activity and stabilize the released cAMP 67,68 . Finally, cAMP was quantified using the cAMP Select ELISA kit (Cayman Chemical, Ann Arbor, USA) according to the manufacturer's instructions.…”

Progestins as Anticancer Drugs and Chemosensitizers, New Targets and Applications

“…In the last decades, the membrane progesterone receptors (mPRα) and progesterone receptor membrane component 1 (PRGMC1) have been considered as possible participants in MDR. It has been recently shown that mPRα activated by progestin nomegestrole acetate (NMGA) caused Pgp mRNA up-regulation in HepG2 and Huh7 cells [ 105 ]. This was the first mention of mPR as a regulator of the drug efflux linked to MDR.…”