Tazemetostat synergistically combats multidrug resistance by the unique triple inhibition of ABCB1, ABCC1, and ABCG2 efflux transporters in vitro and ex vivo.

ATP-binding cassette (ABC) drug efflux transporters and drug metabolizing enzymes play crucial roles in pharmacokinetic drug-drug interactions and multidrug tumor resistance (MDR). Tazemetostat (EPZ-6438, Tazverik) is a novel epigenetic drug that has been recently approved for the therapy of advanced epithelioid sarcoma and follicular lymphoma. Additionally, this medication is currently being clinically tested to treat several other cancers such as non-small cell lung cancer (NSCLC). This study aimed to investigate the inhibitory effects of tazemetostat on selected ABC transporters/cytochrome P450 3A4 (CYP3A4) enzyme to comprehensively explore its role in MDR. First, our accumulation and molecular docking studies showed that tazemetostat is a unique triple inhibitor of ABCB1, ABCC1, and ABCG2 transporters. In contrast, tazemetostat exhibited only low level of interaction with the CYP3A4 isozyme. Drug combination assays confirmed that tazemetostat is a multipotent MDR modulator able to synergize with various conventional chemotherapeutics in vitro. Subsequent caspase activity assays and microscopic staining of apoptotic nuclei proved that the effective induction of apoptosis is behind the observed synergies. Notably, a potent MDR-modulatory capacity of tazemetostat was recorded in primary ex vivo NSCLC explants generated from patients' biopsies. On the contrary, its possible position of pharmacokinetic MDR's victim was excluded in comparative proliferation assays. Finally, tested drug has not been identified as an inducer of resistant phenotype in NSCLC cell lines. In conclusion, we demonstrated that tazemetostat is a unique multispecific chemosensitizer, which has strong potential to overcome limitations seen in the era of traditional MDR modulators.

The Impact of Subclinical Hypothyroidism on the Quality of Life During Pregnancy: Mapping 5-Level Version of EQ-5D and ThyPRO-39.

OBJECTIVES: To describe how subclinical hypothyroidism (SubHypo) influences the quality of life (QoL) during pregnancy. METHODS: In primary data collection (NCT04167423), thyroid stimulating hormone (TSH), free thyroxine (FT4), thyroid peroxidase antibodies, generic quality of life (QoL; 5-level version of EQ-5D [EQ-5D-5L]), and disease-specific QoL (ThyPRO-39) were measured among pregnant women. SubHypo during each trimester was defined according to the 2014 European Thyroid Association guidelines (TSH > 2.5, 3.0, and 3.5 IU/L, respectively; with normal FT4). Path analysis described relationships and tested mediation. Linear ordinary least squares, beta, tobit, and two-part regressions were used to map ThyPRO-39 and EQ-5D-5L. Alternative SubHypo definition was tested in sensitivity analysis. RESULTS: A total of 253 women at 14 sites (31 ± 5 years old, 15 ± 6 weeks pregnant) completed the questionnaires. Sixty-one (26%) had SubHypo and differed from 174 (74%) euthyroid women in smoking history (61% vs 41%), primiparity (62% vs 43%) and TSH level (4.1 ± 1.4 vs 1.5 ± 0.7 mIU/L, P < .001). EQ-5D-5L utility in SubHypo (0.89 ± 0.12) was lower than that in euthyroid (0.92 ± 0.11; P = .028) even after adjustment (difference -0.04, P = .033), whereas ocular (P = .001, ThyPRO-39), cognitive symptoms (P = .043), anxiety (P < .0001), and the composite score were higher. The impact of SubHypo on utility was mediated by anxiety. Results were confirmed by sensitivity analysis. Final mapping equation (ordinary least squares) includes goiter symptoms, anxiety, upset stomach, composite score (ThyPRO-39), FT4 levels, and week of pregnancy (determination coefficient 0.36). CONCLUSION: This is the first QoL mapping of SubHypo during pregnancy and the first evidence that SubHypo is associated with a negative impact on QoL. The effect is mediated by anxiety. EQ-5D-5L utilities can be generated based on ThyPRO-39 scores collected in pregnant euthyroid and patients with SubHypo.

Talazoparib Does Not Interact with ABCB1 Transporter or Cytochrome P450s, but Modulates Multidrug Resistance Mediated by ABCC1 and ABCG2: An in Vitro and Ex Vivo Study.

Talazoparib (Talzenna) is a novel poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitor that is clinically used for the therapy of breast cancer. Furthermore, the drug has shown antitumor activity against different cancer types, including non-small cell lung cancer (NSCLC). In this work, we investigated the possible inhibitory interactions of talazoparib toward selected ATP-binding cassette (ABC) drug efflux transporters and cytochrome P450 biotransformation enzymes (CYPs) and evaluated its position in multidrug resistance (MDR). In accumulation studies, talazoparib interacted with the ABCC1 and ABCG2 transporters, but there were no significant effects on ABCB1. Furthermore, incubation assays revealed a negligible capacity of the tested drug to inhibit clinically relevant CYPs. In in vitro drug combination experiments, talazoparib synergistically reversed daunorubicin and mitoxantrone resistance in cells with ABCC1 and ABCG2 expression, respectively. Importantly, the position of an effective MDR modulator was further confirmed in drug combinations performed in ex vivo NSCLC patients-derived explants, whereas the possible victim role was refuted in comparative proliferation experiments. In addition, talazoparib had no significant effects on the mRNA-level expressions of MDR-related ABC transporters in the MCF-7 cellular model. In summary, our study presents a comprehensive overview on the pharmacokinetic drug-drug interactions (DDI) profile of talazoparib. Moreover, we introduced talazoparib as an efficient MDR antagonist.

Rapid Progression of COVID-19-Associated Fatal Capillary Leak Syndrome.

Several cases of capillary leak syndrome (CLS) related to COVID-19 or vaccination against SARS-CoV-2 have been described in the literature. We present a case of a 42-year-old, previously healthy male, presenting with a mild form of COVID-19, who suddenly developed severe shock with hypotension and severe hemoconcentration within hours of admission to the hospital. Volume resuscitation was not effective, increasing hemoglobin (198 g/L on admission, 222 g/L 9 h later) suggested fluid leak into peripheral tissues. After cardiac arrest, the patient was resuscitated and connected to extracorporeal membrane oxygenation, but died shortly afterwards due to refractory heart failure. Retrospective investigation of blood samples confirmed diagnosis of CLS by progressive hypoalbuminemia (40 g/L on admission, 14 g/L 19 h later) and monoclonal gammopathy kappa (4.7 g/L). Patient's CLS was triggered by COVID-19, either a first attack of idiopathic CLS called Clarkson's disease or a COVID-19-induced secondary CLS.

[Pneumothorax, pneumomediastinum and subcutaneous emphysema as complica-tions of COVID-19].

Spontaneous pneumothorax, pneumomediastinum and subcutaneous emphysema are serious complications of COVID-19 infection caused by SARS-CoV-2, occurring in approximately 1% of hospitalized patients. The risk increases with the accumulation of risk factors, namely moderate or severe illness, high-flow oxygen therapy and noninvasive ventilation. The pathophysiology may be contributed to by patient self-inflicted lung injury. Hypoxia-induced respiratory effort in patients with pneumonia puts an enormous load on certain parts of their lungs, leading to subsequent progression of lung tissue damage. These complications start with destruction of the alveolar membrane, accompanied by emergence of a pulmonary bulla. Rupture of the bulla results in air leaking to the pleural space (pneumothorax). In the case of pneumomediastinum, the air spreads within the peribronchial interstitium along the airways to the mediastinum and subcutaneous tissues (Macklin effect). While pneumomediastinum and subcutaneous emphysema resolve spontaneously in most cases, pneumothorax treatment depends on its magnitude. While small pneumothorax may be managed conservatively, large pneumothorax usually requires active treatment with an acute chest drain; the latter is also associated with worse prognosis and a higher chance of death. We report air-leak complications in nine COVID-19 patients, of whom seven had spontaneous pneumothorax and four of them died. Three patients developed spontaneous pneumomediastinum together with subcutaneous emphysema, with two of them surviving. One patient with combination of pneumothorax, pneumomediastinum and subcutaneous emphysema died. These complications may accompany moderate or severe COVID-19-associated pneumonia, mostly the late phase of the disease. They should be considered when patients complain of sudden chest or back pain or worsening respiratory insufficiency.

Bruton's Tyrosine Kinase Inhibitor Zanubrutinib Effectively Modulates Cancer Resistance by Inhibiting Anthracycline Metabolism and Efflux.

Zanubrutinib (ZAN) is a Bruton's tyrosine kinase inhibitor recently approved for the treatment of some non-Hodgkin lymphomas. In clinical trials, ZAN is often combined with standard anthracycline (ANT) chemotherapy. Although ANTs are generally effective, drug resistance is a crucial obstacle that leads to treatment discontinuation. This study showed that ZAN counteracts ANT resistance by targeting aldo-keto reductase 1C3 (AKR1C3) and ATP-binding cassette (ABC) transporters. AKR1C3 catalyses the transformation of ANTs to less potent hydroxy-metabolites, whereas transporters decrease the ANT-effective concentrations by pumping them out of the cancer cells. In our experiments, ZAN inhibited the AKR1C3-mediated inactivation of daunorubicin (DAUN) at both the recombinant and cellular levels. In the drug combination experiments, ZAN synergistically sensitised AKR1C3-expressing HCT116 and A549 cells to DAUN treatment. Gene induction studies further confirmed that ZAN did not increase the intracellular level of AKR1C3 mRNA; thus, the drug combination effect is not abolished by enzyme induction. Finally, in accumulation assays, ZAN was found to interfere with the DAUN efflux mediated by the ABCB1, ABCG2, and ABCC1 transporters, which might further contribute to the reversal of ANT resistance. In summary, our data provide the rationale for ZAN inclusion in ANT-based therapy and suggest its potential for the treatment of tumours expressing AKR1C3 and/or the above-mentioned ABC transporters.

Isocitrate dehydrogenase 2 inhibitor enasidenib synergizes daunorubicin cytotoxicity by targeting aldo-keto reductase 1C3 and ATP-binding cassette transporters.

Targeting mutations that trigger acute myeloid leukaemia (AML) has emerged as a refined therapeutic approach in recent years. Enasidenib (Idhifa) is the first selective inhibitor of mutated forms of isocitrate dehydrogenase 2 (IDH2) approved against relapsed/refractory AML. In addition to its use as monotherapy, a combination trial of enasidenib with standard intensive induction therapy (daunorubicin + cytarabine) is being evaluated. This study aimed to decipher enasidenib off-target molecular mechanisms involved in anthracycline resistance, such as reduction by carbonyl reducing enzymes (CREs) and drug efflux by ATP-binding cassette (ABC) transporters. We analysed the effect of enasidenib on daunorubicin (Daun) reduction by several recombinant CREs and different human cell lines expressing aldo-keto reductase 1C3 (AKR1C3) exogenously (HCT116) or endogenously (A549 and KG1a). Additionally, A431 cell models overexpressing ABCB1, ABCG2, or ABCC1 were employed to evaluate enasidenib modulation of Daun efflux. Furthermore, the potential synergism of enasidenib over Daun cytotoxicity was quantified amongst all the cell models. Enasidenib selectively inhibited AKR1C3-mediated inactivation of Daun in vitro and in cell lines expressing AKR1C3, as well as its extrusion by ABCB1, ABCG2, and ABCC1 transporters, thus synergizing Daun cytotoxicity to overcome resistance. This work provides in vitro evidence on enasidenib-mediated targeting of the anthracycline resistance actors AKR1C3 and ABC transporters under clinically achievable concentrations. Our findings may encourage its combination with intensive chemotherapy and even suggest that the effectiveness of enasidenib as monotherapy against AML could lie beyond the targeting of mIDH2.

Substituted N-phenylitaconamides as inhibitors of mycobacteria and mycobacterial isocitrate lyase.

Novel antimycobacterial drugs are needed, especially those with dual activity against both actively growing and non-replicating subpopulations of mycobacteria. Isocitrate lyase (ICL) is one of proposed targets and this enzyme is inhibited by itaconic acid. That is why we have designed and prepared sixteen amides of itaconic acid and various anilines and amine antimicrobial drugs to evaluate them as potential inhibitors of ICL and antimycobacterial agents. N-Phenylitaconamides were prepared from itaconic anhydride and substituted anilines (yields 57-99%). They were characterized and evaluated against mycobacterial ICL and against actively growing mycobacteria (M. tuberculosis H37Rv, M. avium, two strains of M. kansasii). All derivatives showed antimycobacterial efficacy with minimum inhibitory concentrations starting from 125 µM. M. kansasii was the most susceptible species. Itaconamides derived from sulfonamides or p-aminosalicylic acid were optimal for activity against extracellular mycobacteria. ICL1 was significantly inhibited by two compounds, with 2-methylene-4-[(4-nitrophenyl)amino]-4-oxobutanoic acid 1k being the most potent (36% inhibition at 10 µM), which was also more efficient than two comparators. Molecular docking revealed its mode of binding to the enzyme. Using in silico tools, physicochemical properties and structural features for drug-likeness and gastrointestinal absorption were evaluated.

Alisertib shows negligible potential for perpetrating pharmacokinetic drug-drug interactions on ABCB1, ABCG2 and cytochromes P450, but acts as dual-activity resistance modulator through the inhibition of ABCC1 transporter.

Alisertib (MLN8237), a novel Aurora A kinase inhibitor, is currently being clinically tested in late-phase trials for the therapy of various malignancies. In the present work, we describe alisertib's potential to perpetrate pharmacokinetic drug-drug interactions (DDIs) and/or to act as an antagonist of multidrug resistance (MDR). In accumulation assays, alisertib potently inhibited ABCC1 transporter, but not ABCB1 or ABCG2. The results of molecular modeling suggested a bifunctional mechanism for interaction on ABCC1. In addition, alisertib was characterized as a low- to moderate-affinity inhibitor of recombinant CYP3A4, CYP2C8, CYP2C9, CYP2C19, and CYP2D6 isoenzymes, but without potential clinical relevance. Drug combination studies revealed the capability of alisertib to synergistically antagonize ABCC1-mediated resistance to daunorubicin. Although alisertib exhibited substrate characteristics toward ABCB1 transporter in monolayer transport assays, comparative proliferation studies showed lack of its MDR-victim behavior in cells overexpressing ABCB1 as well as ABCG2 and ABCC1. Lastly, alisertib did not affect the expression of ABCC1, ABCG2, ABCB1 transporters and CYP1A2, CYP3A4, CYP2B6 isozymes on mRNA level in various systemic and tumoral models. In conclusion, our study suggests that alisertib is a drug candidate with negligible potential for perpetrating systemic pharmacokinetic DDIs on ABCB1, ABCG2 and cytochromes P450. In addition, we introduce alisertib as an effective dual-activity chemosensitizer whose MDR-antagonistic capacities are not impaired by efflux or effect on MDR phenotype. Our in vitro findings provide important pieces of information for clinicians when introducing alisertib into the clinical area.

Tepotinib Inhibits Several Drug Efflux Transporters and Biotransformation Enzymes: The Role in Drug-Drug Interactions and Targeting Cytostatic Resistance In Vitro and Ex Vivo.

Tepotinib is a novel tyrosine kinase inhibitor recently approved for the treatment of non-small cell lung cancer (NSCLC). In this study, we evaluated the tepotinib's potential to perpetrate pharmacokinetic drug interactions and modulate multidrug resistance (MDR). Accumulation studies showed that tepotinib potently inhibits ABCB1 and ABCG2 efflux transporters, which was confirmed by molecular docking. In addition, tepotinib inhibited several recombinant cytochrome P450 (CYP) isoforms with varying potency. In subsequent drug combination experiments, tepotinib synergistically reversed daunorubicin and mitoxantrone resistance in cells with ABCB1 and ABCG2 overexpression, respectively. Remarkably, MDR-modulatory properties were confirmed in ex vivo explants derived from NSCLC patients. Furthermore, we demonstrated that anticancer effect of tepotinib is not influenced by the presence of ABC transporters associated with MDR, although monolayer transport assays designated it as ABCB1 substrate. Finally, tested drug was observed to have negligible effect on the expression of clinically relevant drug efflux transporters and CYP enzymes. In conclusion, our findings provide complex overview on the tepotinib's drug interaction profile and suggest a promising novel therapeutic strategy for future clinical investigations.

Inhibition of AKR1B10-mediated metabolism of daunorubicin as a novel off-target effect for the Bcr-Abl tyrosine kinase inhibitor dasatinib.

Bcr-Abl tyrosine kinase inhibitors significantly improved Philadelphia chromosome-positive leukaemia therapy. Apart from Bcr-Abl kinase, imatinib, dasatinib, nilotinib, bosutinib and ponatinib are known to have additional off-target effects that might contribute to their antitumoural activities. In our study, we identified aldo-keto reductase 1B10 (AKR1B10) as a novel target for dasatinib. The enzyme AKR1B10 is upregulated in several cancers and influences the metabolism of chemotherapy drugs, including anthracyclines. AKR1B10 reduces anthracyclines to alcohol metabolites that show less antineoplastic properties and tend to accumulate in cardiac tissue. In our experiments, clinically achievable concentrations of dasatinib selectively inhibited AKR1B10 both in experiments with recombinant enzyme (Ki = 0.6 µM) and in a cellular model (IC50 = 0.5 µM). Subsequently, the ability of dasatinib to attenuate AKR1B10-mediated daunorubicin (Daun) resistance was determined in AKR1B10-overexpressing cells. We have demonstrated that dasatinib can synergize with Daun in human cancer cells and enhance its therapeutic effectiveness. Taken together, our results provide new information on how dasatinib may act beyond targeting Bcr-Abl kinase, which may help to design new chemotherapy regimens, including those with anthracyclines.

Selective inhibition of aldo-keto reductase 1C3: a novel mechanism involved in midostaurin and daunorubicin synergism.

Midostaurin is an FMS-like tyrosine kinase 3 receptor (FLT3) inhibitor that provides renewed hope for treating acute myeloid leukaemia (AML). The limited efficacy of this compound as a monotherapy contrasts with that of its synergistic combination with standard cytarabine and daunorubicin (Dau), suggesting a therapeutic benefit that is not driven only by FLT3 inhibition. In an AML context, the activity of the enzyme aldo-keto reductase 1C3 (AKR1C3) is a crucial factor in chemotherapy resistance, as it mediates the intracellular transformation of anthracyclines to less active hydroxy metabolites. Here, we report that midostaurin is a potent inhibitor of Dau inactivation mediated by AKR1C3 in both its recombinant form as well as during its overexpression in a transfected cell model. Likewise, in the FLT3- AML cell line KG1a, midostaurin was able to increase the cellular accumulation of Dau and significantly decrease its metabolism by AKR1C3 simultaneously. The combination of those mechanisms increased the nuclear localization of Dau, thus synergizing its cytotoxic effects on KG1a cells. Our results provide new in vitro evidence of how the therapeutic activity of midostaurin could operate beyond targeting the FLT3 receptor.

Bruton's Tyrosine Kinase Inhibitors Ibrutinib and Acalabrutinib Counteract Anthracycline Resistance in Cancer Cells Expressing AKR1C3.

Over the last few years, aldo-keto reductase family 1 member C3 (AKR1C3) has been associated with the emergence of multidrug resistance (MDR), thereby hindering chemotherapy against cancer. In particular, impaired efficacy of the gold standards of induction therapy in acute myeloid leukaemia (AML) has been correlated with AKR1C3 expression, as this enzyme metabolises several drugs including anthracyclines. Therefore, the development of selective AKR1C3 inhibitors may help to overcome chemoresistance in clinical practice. In this regard, we demonstrated that Bruton's tyrosine kinase (BTK) inhibitors ibrutinib and acalabrutinib efficiently prevented daunorubicin (Dau) inactivation mediated by AKR1C3 in both its recombinant form as well as during its overexpression in cancer cells. This revealed a synergistic effect of BTK inhibitors on Dau cytotoxicity in cancer cells expressing AKR1C3 both exogenously and endogenously, thus reverting anthracycline resistance in vitro. These findings suggest that BTK inhibitors have a novel off-target action, which can be exploited against leukaemia through combination regimens with standard chemotherapeutics like anthracyclines.

ThDione: A Powerful Electron-Withdrawing Moiety for Push-Pull Molecules.

A series of new push-pull chromophores based on a combined cyclopenta[c]thiophene-4,6-dione (ThDione) acceptor, N,N-dimethylaniline, N-piperidinylthiophene or ferrocene donors, and ethylene or buta-1,3-dienylene π-linkers has been designed and synthesized. Utilizing one or two ThDione acceptors afforded linear or branched push-pull molecules. Experimental and theoretical study of their fundamental properties revealed thermal robustness up to 260 °C, a electrochemical/optical HOMO-LUMO gap that is tunable within the range of 1.47-2.19/1.99-2.39 eV, and thorough elucidation of structure-property relationships. Compared to currently available portfolio of heterocyclic electron-withdrawing units, ThDione proved to be a powerful and versatile acceptor unit. It imparts significant intramolecular charge transfer and polarizes the π-system, which results in enhanced (non)linear optical response.

Targeting Pharmacokinetic Drug Resistance in Acute Myeloid Leukemia Cells with CDK4/6 Inhibitors.

Pharmacotherapy of acute myeloid leukemia (AML) remains challenging, and the disease has one of the lowest curability rates among hematological malignancies. The therapy outcomes are often compromised by the existence of a resistant AML phenotype associated with overexpression of ABCB1 and ABCG2 transporters. Because AML induction therapy frequently consists of anthracycline-like drugs, their efficiency may also be diminished by drug biotransformation via carbonyl reducing enzymes (CRE). In this study, we investigated the modulatory potential of the CDK4/6 inhibitors abemaciclib, palbociclib, and ribociclib on AML resistance using peripheral blood mononuclear cells (PBMC) isolated from patients with de novo diagnosed AML. We first confirmed inhibitory effect of the tested drugs on ABCB1 and ABCG2 in ABC transporter-expressing resistant HL-60 cells while also showing the ability to sensitize the cells to cytotoxic drugs even as no effect on AML-relevant CRE isoforms was observed. All tested CDK4/6 inhibitors elevated mitoxantrone accumulations in CD34+ PBMC and enhanced accumulation of mitoxantrone was found with abemaciclib and ribociclib in PBMC of FLT3-ITD- patients. Importantly, the accumulation rate in the presence of CDK4/6 inhibitors positively correlated with ABCB1 expression in CD34+ patients and led to enhanced apoptosis of PBMC in contrast to CD34- samples. In summary, combination therapy involving CDK4/6 inhibitors could favorably target multidrug resistance, especially when personalized based on CD34- and ABCB1-related markers.

Entrectinib reverses cytostatic resistance through the inhibition of ABCB1 efflux transporter, but not the CYP3A4 drug-metabolizing enzyme.

Entrectinib is a new tyrosine kinase inhibitor that was recently approved for the treatment of ROS1-positive metastatic non-small cell lung cancer (NSCLC). In this study, we aimed to characterize its potential to act as a modulator of pharmacokinetic cytostatic resistance and perpetrator of drug interactions. In accumulation studies, entrectinib exhibited potent inhibition of ABCB1, while only moderate interaction was recorded for ABCG2 and ABCC1 efflux transporters. Furthermore, incubation assays revealed the potential of this drug to inhibit various recombinant cytochrome P450 enzymes, which can be ranked according to inhibitory affinities as follows: CYP2C8 ≈ CYP3A4 > CYP2C9 > CYP2C19 ≈ CYP3A5 > CYP2D6 > CYP2B6 > CYP1A2. Additionally, in silico docking analysis confirmed entrectinib's interactions with ABCB1 and CYP3A4 and resolved their possible molecular background. In subsequent drug combination experiments, we demonstrated the ability of entrectinib to synergize with daunorubicin in various ABCB1-expressing cellular models. Moreover, the comparative proliferation study results suggested that the anticancer efficacy of entrectinib is not affected by the functional presence of tested ABC transporters. In contrast to ABCB1-related data, no resistance reversal effect was recorded for the combination with docetaxel in HepG2-CYP3A4 cells. In the final experimental set, we observed no significant changes in ABCB1, ABCG2, ABCC1 or CYP3A4 gene expression in NSCLC cells exposed to entrectinib. In summary, our work indicates that entrectinib may be a perpetrator of clinically relevant pharmacokinetic drug interactions and modulator of ABCB1-mediated resistance. Our in vitro results might provide a valuable foundation for future clinical investigations.

Interactions of antileukemic drugs with daunorubicin reductases: could reductases affect the clinical efficacy of daunorubicin chemoregimens?

Although novel anticancer drugs are being developed intensively, anthracyclines remain the gold standard in the treatment of acute myeloid leukaemia (AML). The reductive conversion of daunorubicin (Dau) to less active daunorubicinol (Dau-ol) is an important mechanism that contributes to the development of pharmacokinetic anthracycline resistance. Dau is a key component in many AML regimes, in which it is combined with many drugs, including all-trans-retinoic acid (ATRA), cytarabine, cladribine and prednisolone. In the present study, we investigated the influence of these anticancer drugs on the reductive Dau metabolism mediated by the aldo-keto reductases AKR1A1, 1B10, 1C3, and 7A2 and carbonyl reductase 1 (CBR1). In incubation experiments with recombinant enzymes, cladribine and cytarabine did not significantly inhibit the activity of the tested enzymes. Prednisolone inhibited AKR1C3 with an IC50 of 41.73 µM, while ATRA decreased the activity of AKR1B10 (IC50 = 78.33 µM) and AKR1C3 (IC50 = 1.17 µM). Subsequent studies showed that AKR1C3 inhibition mediated by ATRA exhibited tight binding (Kiapp = 0.54 µM). Further, the combination of 1 µM ATRA with different concentrations of Dau demonstrated synergistic effects in HCT116 and KG1a human cells expressing AKR1C3. Our results suggest that ATRA-mediated inhibition of AKR1C3 can contribute to the mechanisms that are hidden beyond the beneficial clinical outcome of the ATRA-Dau combination.

Ensartinib (X-396) Effectively Modulates Pharmacokinetic Resistance Mediated by ABCB1 and ABCG2 Drug Efflux Transporters and CYP3A4 Biotransformation Enzyme.

Ensartinib (X-396) is a promising tyrosine kinase inhibitor currently undergoing advanced clinical evaluation for the treatment of non-small cell lung cancer. In this work, we investigate possible interactions of this promising drug candidate with ATP-binding cassette (ABC) drug efflux transporters and cytochrome P450 biotransformation enzymes (CYPs), which play major roles in multidrug resistance (MDR) and pharmacokinetic drug-drug interactions (DDIs). Accumulation studies showed that ensartinib is a potent inhibitor of ABCB1 and ABCG2 transporters. Additionally, incubation experiments with recombinant CYPs showed that ensartinib significantly inhibits CYP3A4 and CYP2C9. Subsequent molecular docking studies confirmed these findings. Drug combination experiments demonstrated that ensartinib synergistically potentiates the antiproliferative effects of daunorubicin, mitoxantrone, and docetaxel in ABCB1, ABCG2, and CYP3A4-overexpressing cellular models, respectively. Advantageously, ensartinib's antitumor efficiency was not compromised by the presence of MDR-associated ABC transporters, although it acted as a substrate of ABCB1 in Madin-Darby Canine Kidney II (MDCKII) monolayer transport assays. Finally, we demonstrated that ensartinib had no significant effect on the mRNA-level expression of examined transporters and enzymes in physiological and lung tumor cellular models. In conclusion, ensartinib may perpetrate clinically relevant pharmacokinetic DDIs and modulate ABCB1-, ABCG2-, and CYP3A4-mediated MDR. The in vitro findings presented here will provide a valuable foundation for future in vivo investigations.

Phenolic N-monosubstituted carbamates: Antitubercular and toxicity evaluation of multi-targeting compounds.

The research of novel antimycobacterial drugs represents a cutting-edge topic. Thirty phenolic N-monosubstituted carbamates, derivatives of salicylanilides and 4-chlorophenol, were investigated against Mycobacterium tuberculosis H37Ra, H37Rv including multidrug- and extensively drug-resistant strains, Mycobacterium avium, Mycobacterium kansasii, Mycobacterium aurum and Mycobacterium smegmatis as representatives of nontuberculous mycobacteria (NTM) and for their cytotoxic and cytostatic properties in HepG2 cells. Since salicylanilides are multi-targeting compounds, we determined also inhibition of mycobacterial isocitrate lyase, an enzyme involved in the maintenance of persistent tuberculous infection. The minimum inhibitory concentrations were from ≤0.5 µM for both drug-susceptible and resistant M. tuberculosis and from ≤0.79 µM for NTM with no cross-resistance to established drugs. The presence of halogenated salicylanilide scaffold results into an improved activity. We have verified that isocitrate lyase is not a key target, presented carbamates showed only moderate inhibitory activity (up to 18% at a concentration of 10 µM). Most of the compounds showed no cytotoxicity for HepG2 cells and some of them were without cytostatic activity. Cytotoxicity-based selectivity indexes of several carbamates for M. tuberculosis, including resistant strains, were higher than 125, thus favouring some derivatives as promising features for future development.

Interactions of Alectinib with Human ATP-Binding Cassette Drug Efflux Transporters and Cytochrome P450 Biotransformation Enzymes: Effect on Pharmacokinetic Multidrug Resistance.

Alectinib is a tyrosine kinase inhibitor currently used as a first-line treatment of anaplastic lymphoma kinase-positive metastatic nonsmall cell lung cancer (NSCLC). In the present work, we investigated possible interactions of this novel drug with ATP-binding cassette (ABC) drug efflux transporters and cytochrome P450 (P450) biotransformation enzymes that play significant roles in the phenomenon of multidrug resistance (MDR) of cancer cells as well as in pharmacokinetic drug-drug interactions. Using accumulation studies in Madin-Darby canine kidney subtype 2 (MDCKII) cells alectinib was identified as an inhibitor of ABCB1 and ABCG2 but not of ABCC1. In subsequent drug combination studies, we demonstrated the ability for alectinib to effectively overcome MDR in ABCB1- and ABCG2-overexpressing MDCKII and A431 cells. To describe the pharmacokinetic interaction profile of alectinib in a complete fashion, its possible inhibitory properties toward clinically relevant P450 enzymes (i.e., CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, or CYP3A5) were evaluated using human P450-expressing insect microsomes, revealing alectinib as a poor interactor. Advantageously for its use in pharmacotherapy, alectinib further exhibited negligible potential to cause any changes in expression of ABCB1, ABCG2, ABCC1, CYP1A2, CYP3A4, and CYP2B6 in intestine, liver, and NSCLC models. Our in vitro observations might serve as a valuable foundation for future in vivo studies that could support the rationale for our conclusions and possibly enable providing more efficient and safer therapy to many oncological patients.