Ribociclib is a novel cyclin-dependent kinase (CDK) 4 and 6 selective inhibitor that recently gained breakthrough therapy status and global approval for advanced breast cancer treatment. ATP-binding cassette (ABC) transporters may become a site of severe drug interactions and a mechanism of multidrug resistance (MDR) development. With respect to rapid progress of ribociclib in the clinical field, we aimed to identify its interactions with ABC transporters and cytochrome P450 (CYP) isoenzymes and evaluate its potential to overcome transporter-mediated MDR using established in vitro methods. Our data showed accelerated ABCB1 inhibitor LY335979-sensitive, basolateral-to-apical transport of ribociclib across MDCKII-ABCB1 cell monolayers, which identified ribociclib as an ABCB1 substrate. The antiproliferative studies supported this finding by demonstrating significantly higher EC50 value in ABCB1-, but not ABCG2- or ABCC1-expressing MDCKII cells, than in the parent MDCKII cell line. Furthermore, we observed significant inhibitory effects of ribociclib on ABCB1 and ABCG2 transporters and CYP1A2, CYP3A4, CYP3A5, and CYP2C9 isoform activity in human CYP-expressing insect microsomes. The ribociclib-induced ABCB1 and ABCG2 inhibition further reversed daunorubicin and mitoxantrone resistance in MDCKII and human MCF-7 breast carcinoma cell lines, indicating a synergistic antiproliferative effect, without affecting ABCB1 or ABCG2 expression. In summary, our data indicate that ABCB1 affects ribociclib transport across the membranes and the high potential of ribociclib for drug-drug interactions (DDIs) through ABCB1 and ABCG2 transporters and CYP isoforms. Moreover, we demonstrate the beneficial MDR-reversing potential of ribociclib, which could be further exploited in novel anticancer treatment strategies.
- MeSH
- ABC transportér z rodiny G, člen 2 antagonisté a inhibitory metabolismus MeSH
- aminopyridiny farmakokinetika MeSH
- buňky MDCK MeSH
- inhibitory cytochromu P450 farmakokinetika MeSH
- izoenzymy antagonisté a inhibitory metabolismus MeSH
- lékové interakce fyziologie MeSH
- lidé MeSH
- MFC-7 buňky MeSH
- nádorové proteiny antagonisté a inhibitory metabolismus MeSH
- P-glykoproteiny antagonisté a inhibitory metabolismus MeSH
- psi MeSH
- puriny farmakokinetika MeSH
- substrátová specifita účinky léků fyziologie MeSH
- systém (enzymů) cytochromů P-450 metabolismus MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- psi MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
OBJECTIVES: 2-Nitrobenzanthrone (2-NBA) has recently been detected in ambient air particulate matter. Its isomer 3-nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust. Understanding which enzymes are involved in metabolism of these toxicants is important in the assessment of individual susceptibility. Here, metabolism of 2-NBA and 3-NBA by rat and mouse hepatic microsomes containing cytochromes P450 (CYPs), their reductase (NADPH:CYP reductase), and NADH:cytochrome b5 reductase was investigated under anaerobic and aerobic conditions. In addition, using the same microsomal systems, 2-NBA and 3-NBA were evaluated to be enzymatically activated under anaerobic conditions to species generating 2-NBA- and 3-NBA-derived DNA adducts. METHODS: High performance liquid chromatography (HPLC) with ultraviolet (UV) detection was employed for the separation and characterization of 2-NBA and 3-NBA metabolites formed by hepatic microsomes of rats and mice under the anaerobic and aerobic conditions. Microsomal systems isolated from the liver of the control (untreated) rats and rats pretreated with Sudan I, β-naphthoflavone (β-NF), phenobarbital (PB), ethanol and pregnenolon 16α-carbonitrile (PCN), the inducers of cytochromes P450 (CYP) 1A1, 1A1/2, 2B, 2E1 and 3A, respectively, were used in this study. Microsomes of mouse models, a control mouse line (wild-type, WT) and Hepatic Cytochrome P450 Reductase Null (HRN) mice with deleted gene of NADPH:CYP reductase in the liver, thus absenting this enzyme in their livers, were also employed. To detect and quantify the 2-NBA- and 3-NBA-derived DNA adducts, the 32P postlabeling technique was used. RESULTS: Both reductive metabolite of 3-NBA, 3-aminobenzanthrone (3-ABA), found to be formed predominantly under the anaerobic conditions, and two 3-NBA oxidative metabolites, whose structures have not yet been investigated, were formed by several microsomal systems used in the study. Whereas a 3-NBA reductive metabolite, 3-ABA, was found only in the microsomal systems of control rats, the rats treated with β-NF and PB, and microsomes of WT and HRN mice, all hepatic microsomes tested in the study were capable of activating this carcinogen under the reductive conditions to form DNA adducts. A stability of a reactive intermediate of 3-NBA, N-hydroxy-3-aminobenzanthrone that is formed during 3-NBA reduction to 3-ABA, to form nitrenium (and/or carbenium) ions binding to DNA in individual microsomes as well as binding of these ions to proteins of these microsomes, might be the reasons explaining this phenomenon. In contrast to 3-NBA, its isomer 2-NBA was not metabolized by any of the used enzymatic systems both under the anaerobic and aerobic conditions. Likewise, no DNA adducts were detectable after reaction of 2-NBA in these systems with DNA. CONCLUSIONS: The results found in this study, the first report on the metabolism of 2-NBA and 3-NBA by rat and mouse hepatic microsomes demonstrate that 3-NBA, in contrast to 2-NBA, is reductively activated to form 3-NBA-derived DNA adducts by these enzymatic systems. NADPH:CYP reductase can be responsible for formation of these DNA adducts in rat livers, while NADH:cytochrome b5 reductase can contribute to this process in livers of HRN mice.
- MeSH
- adukty DNA metabolismus MeSH
- aerobióza fyziologie MeSH
- anaerobióza fyziologie MeSH
- benz(a)anthraceny farmakokinetika toxicita MeSH
- cytochrom-B(5)-reduktasa genetika metabolismus MeSH
- inbrední kmeny myší MeSH
- jaterní mikrozomy enzymologie MeSH
- karcinogeny farmakokinetika toxicita MeSH
- krysa rodu rattus MeSH
- látky znečišťující vzduch farmakokinetika toxicita MeSH
- metabolická inaktivace fyziologie MeSH
- modely u zvířat MeSH
- myši knockoutované MeSH
- myši MeSH
- NADPH-cytochrom c-reduktasa metabolismus MeSH
- potkani Wistar MeSH
- substrátová specifita fyziologie MeSH
- systém (enzymů) cytochromů P-450 metabolismus MeSH
- výfukové emise vozidel toxicita MeSH
- zdraví ve městech MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Chirality is a ubiquitous feature present in all biological systems that plays a very important role in many processes. Drug metabolism is one of these and is the subject of this review. Chiral drugs can be metabolized without changes in their chiral characteristics, but also their biotransformation may give rise to a new chiral center. On the other hand, prochiral drugs are always metabolized to chiral metabolites. The ratio of formed enantiomers/diastereoisomers is the constant known as enzyme stereospecificity, and this is as important a characteristic for each enzyme-substrate pair as is the Michaelis constant. Drugs are often substrates for multiple biotransformation enzymes, and all enzymes involved may metabolize a chiral or prochiral drug with different stereospecificity so that variant enantiomer ratios are achieved. Enzyme stereospecificity of whole cell fraction is the sum of the stereospecificities of all enzymes participating in metabolism of a substrate. Differing stereospecificities in the metabolism of a drug between whole cell fraction and enzymes point to the contribution of other enzymes. Using several drugs as examples, this review shows that enzyme stereospecificity can serve as a powerful tool in searching for new biotransformation enzymes. Although it is not often used in this way, it is clear that this is possible. There are today drugs with well-known chiral metabolism, but, inasmuch as many xenobiotics are poorly characterized in terms of chiral metabolism, enzyme stereospecificity could be widely utilized in researching such substances.
- MeSH
- biotransformace fyziologie MeSH
- jaterní mikrozomy enzymologie MeSH
- léčivé přípravky chemie metabolismus MeSH
- lidé MeSH
- molekulární sekvence - údaje MeSH
- sekvence aminokyselin MeSH
- stereoizomerie MeSH
- substrátová specifita fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
