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The inhibitory effects of mitragynine on P-glycoprotein in vitro

Rusli N, Amanah A, Kaur G, Adenan MI, Sulaiman SF, Wahab HA, et al.

Naunyn Schmiedebergs Arch Pharmacol, 2019 04;392(4):481-496.
PMID: 30604191 DOI: 10.1007/s00210-018-01605-y

Mitragynine is a major component isolated from Mitragyna speciosa Korth or kratom, a medicinal plant known for its opiate-like and euphoric properties. Multiple toxicity and fatal cases involving mitragynine or kratom have been reported but the underlying causes remain unclear. P-glycoprotein (P-gp) is a multidrug transporter which modulates the pharmacokinetics of xenobiotics and plays a key role in mediating drug-drug interactions. This study investigated the effects of mitragynine on P-gp transport activity, mRNA, and protein expression in Caco-2 cells using molecular docking, bidirectional assay, RT-qPCR, Western blot analysis, and immunocytochemistry techniques, respectively. Molecular docking simulation revealed that mitragynine interacts with important residues at the nucleotide binding domain (NBD) site of the P-gp structure but not with the residues from the substrate binding site. This was consistent with subsequent experimental work as mitragynine exhibited low permeability across the cell monolayer but inhibited digoxin transport at 10 μM, similar to quinidine. The reduction of P-gp activity in vitro was further contributed by the downregulation of mRNA and protein expression of P-gp. In summary, mitragynine is likely a P-gp inhibitor in vitro but not a substrate. Hence, concurrent administration of mitragynine-containing kratom products with psychoactive drugs which are P-gp substrates may lead to clinically significant toxicity. Further clinical study to prove this point is needed.

Matched MeSH terms: P-Glycoprotein/antagonists & inhibitors*
Fulltext Influences of proton pump inhibitor on Helicobacter pylori adherence to the gastrointestinal cell lines

Omar MS, Damanhuri NS, Kumolosasi E

Turk J Gastroenterol, 2017 Jan;28(1):53-59.
PMID: 27991853 DOI: 10.5152/tjg.2016.0409

BACKGROUND/AIMS: Helicobacter pylori is a carcinogenic bacterium that could induce P-glycoprotein expression in the human gastrointestinal tract. Bacterial adherence to the gastrointestinal cell lines could be influenced by the level of P-glycoprotein. This study aimed to determine the influence of proton pump inhibitors that exhibit an inhibitory effect on P-glycoprotein in gastrointestinal carcinoma cell lines, namely Caco-2 and LS174T, in relation to H. pylori adherence.
MATERIALS AND METHODS: Caco-2 and LS174T cells lines treated with omeprazole and esomeprazole were used in this study to assess the bacterial attachment of H. pylori within certain incubation periods.
RESULTS: The presence of proton pump inhibitors increased the H. pylori adherence in a time-dependent manner in both Caco-2 and LS174T cell lines. The double inhibition of P-glycoprotein using proton pump inhibitor and P-glycoprotein inhibitor caused low P-glycoprotein expression in the cell lines, resulting in higher H. pylori adherence compared to the control cell lines.
CONCLUSION: Proton pump inhibitors may alter P-glycoprotein expression in the gastrointestinal tract, and subsequently H. pylori adherence on the cell lines, and may contribute to resistance to drug therapy.

Matched MeSH terms: P-Glycoprotein/antagonists & inhibitors*
Insight into the molecular mechanism of P-glycoprotein mediated drug toxicity induced by bioflavonoids: an integrated computational approach

Wongrattanakamon P, Lee VS, Nimmanpipug P, Sirithunyalug B, Chansakaow S, Jiranusornkul S

Toxicol. Mech. Methods, 2017 May;27(4):253-271.
PMID: 27996361 DOI: 10.1080/15376516.2016.1273428

In this work, molecular docking, pharmacophore modeling and molecular dynamics (MD) simulation were rendered for the mouse P-glycoprotein (P-gp) (code: 4Q9H) and bioflavonoids; amorphigenin, chrysin, epigallocatechin, formononetin and rotenone including a positive control; verapamil to identify protein-ligand interaction features including binding affinities, interaction characteristics, hot-spot amino acid residues and complex stabilities. These flavonoids occupied the same binding site with high binding affinities and shared the same key residues for their binding interactions and the binding region of the flavonoids was revealed that overlapped the ATP binding region with hydrophobic and hydrophilic interactions suggesting a competitive inhibition mechanism of the compounds. Root mean square deviations (RMSDs) analysis of MD trajectories of the protein-ligand complexes and NBD2 residues, and ligands pointed out these residues were stable throughout the duration of MD simulations. Thus, the applied preliminary structure-based molecular modeling approach of interactions between NBD2 and flavonoids may be gainful to realize the intimate inhibition mechanism of P-gp at NBD2 level and on the basis of the obtained data, it can be concluded that these bioflavonoids have the potential to cause herb-drug interactions or be used as lead molecules for the inhibition of P-gp (as anti-multidrug resistance agents) via the NBD2 blocking mechanism in future.

Matched MeSH terms: P-Glycoprotein/antagonists & inhibitors
Fulltext Modulating multidrug resistance gene in leukaemia cells by short interfering RNA

Lim MN, Lau NS, Chang KM, Leong CF, Zakaria Z

Singapore Med J, 2007 Oct;48(10):932-8.
PMID: 17909680

The multidrug resistance gene, MDR1, is one of the genes responsible for resistance to chemotherapy in the treatment of leukaemia and other cancers. The discovery of RNA interference in mammalian cells has provided a powerful tool to inhibit the expression of this gene. However, very little is known about the transfection of leukaemia cells with short interfering RNA (siRNA) targeted at MDR1. This study aims to evaluate the effectiveness of two chemically-synthesised siRNA in modulating MDR1 gene and inhibiting P-glycoprotein expression in leukaemic cells. We also evaluated two siRNA delivery methods in this study.

Matched MeSH terms: P-Glycoprotein/antagonists & inhibitors*
Fulltext The influence of P-glycoprotein expression in the standard treatment of Helicobacter pylori infection in Sprague Dawley rats

Damanhuri NS, Kumolosasi E, Omar MS, Razak AFA, Mansor AH

Daru, 2021 Jun;29(1):13-22.
PMID: 33405191 DOI: 10.1007/s40199-020-00377-2

BACKGROUND: P-glycoprotein (P-gp) is an Adenosine triphosphate (ATP) dependent drug-efflux pump which is located abundantly in the stomach and protects the gut mucosa from xenobiotic.
OBJECTIVE: The purpose of this study was to investigate the influence of P-gp modulation on the efficacy of treatment regimen.
METHOD: P-gp modulation in rats was performed by using P-gp inducer (150 mg/kg rifampicin) and P-gp inhibitor (10 mg/kg cyclosporine A) for 14 days prior to be infected with Helicobacter pylori (H. pylori). The rats were further divided into groups, which were normal control, vehicle control, antibiotics and omeprazole, antibiotics only and omeprazole only for another 2 weeks of treatment. The ulcer formation and P-gp expression were determined by using macroscopic evaluation and western blot analysis, respectively.
RESULTS: The highest P-gp expression was shown in the induced P-gp rats (2.00 ± 0.68) while the lowest P-gp expression was shown in the inhibited P-gp rats (0.45 ± 0.36) compared to the normal P-gp rats. In all groups, the rats which were infected with H. pylori, had a significant increase (p P-gp expression level and a more severe ulcer formation compared to the healthy rats. The ulcer developed at different levels in the rats with inhibited, induced, or normal P-gp expression. After receiving the standard therapy for H. pylori, it was observed that the healing rate for ulcer was increased to 91% (rats with inhibited P-gp expression), 82% (rats with induced P-gp expression) and 75% in rats with normal P-gp. The use of rifampicin to induce P-gp level was also shown to be effective in eradicating the H. pylori infection.
CONCLUSION: The synergism in the standard therapy by using two antibiotics (clarithromycin and amoxicillin) and proton pump inhibitor (omeprazole) have shown to effectively eradicate the H. pylori infection. Thus, P-gp expression influenced the effectiveness of the treatment.

Matched MeSH terms: P-Glycoprotein/antagonists & inhibitors