A cross-sectional study on the potential drug-drug interaction risk of COVID-19 patients in hospital.

OBJECTIVE: To investigate the incidence of and risk factors for potential drug-drug interactions (DDIs) among elderly patients with corona virus disease 2019 (-COVID-19) in hospital and to explore management strategies to reduce the occurrence of potential DDIs and ensure patient medication safety. MATERIALS AND METHODS: This was a descriptive, retrospective cross-sectional study among patients aged 65 years and older who were hospitalized with COVID-19. Potential DDIs associated with prescriptions containing two or more medicines were analyzed with Lexicomp software, the incidence of DDIs was calculated, recommendations for medication adjustment were formulated, and the χ2-test and binary logistic regression were used to analyze related risk factors. RESULTS: A total of 772 prescriptions were analyzed, 527 (68.26) of which involved 5,732 potential DDIs. The results of this study showed that a total of 152 (28.84%) prescriptions had 270 X risk class potential DDIs (i.e., avoid combining), 313 (59.39%) prescriptions had 1,161 D risk class potential DDIs (i.e., consider therapy modification), and 476 (90.32%) prescriptions had 4,301 C risk class potential DDIs (i.e., monitor therapy). The study findings showed that the total number of drugs (p < 0.001), the length of hospital stay (p < 0.001), and the number of comorbidities (p < 0.001) were risk factors affecting the occurrence of potential DDIs. CONCLUSION: This study identified factors associated with potential DDIs, which can assist in changing medication strategies, preventing adverse drug reactions, and improving clinical efficacy.

[Mechanism of Marsdenia tenacissima against ovarian cancer based on network pharmacology and experimental verification].

The present study aimed to explore the main active components and underlying mechanisms of Marsdenia tenacissima in the treatment of ovarian cancer(OC) through network pharmacology, molecular docking, and in vitro cell experiments. The active components of M. tenacissima were obtained from the literature search, and their potential targets were obtained from SwissTargetPrediction. The OC-related targets were retrieved from Therapeutic Target Database(TTD), Online Mendelian Inheritance in Man(OMIM), GeneCards, and PharmGKB. The common targets of the drug and the disease were screened out by Venn diagram. Cytoscape was used to construct an "active component-target-disease" network, and the core components were screened out according to the node degree. The protein-protein interaction(PPI) network of the common targets was constructed by STRING and Cytoscape, and the core targets were screened out according to the node degree. GO and KEGG enrichment analyses of potential therapeutic targets were carried out with DAVID database. Molecular docking was used to determine the binding activity of some active components to key targets by AutoDock. Finally, the anti-OC activity of M. tenacissima extract was verified based on SKOV3 cells in vitro. The PI3K/AKT signaling pathway was selected for in vitro experimental verification according to the results of GO function and KEGG pathway analyses. Network pharmacology results showed that 39 active components, such as kaempferol, 11α-O-benzoyl-12ß-O-acetyltenacigenin B, and drevogenin Q, were screened out, involving 25 core targets such as AKT1, VEGFA, and EGFR, and the PI3K-AKT signaling pathway was the main pathway of target protein enrichment. The results of molecular docking also showed that the top ten core components showed good binding affinity to the top ten core targets. The results of in vitro experiments showed that M. tenacissima extract could significantly inhibit the proliferation of OC cells, induce apoptosis of OC cells through the mitochondrial pathway, and down-regulate the expression of proteins related to the PI3K/AKT signaling pathway. This study shows that M. tenacissima has the characteristics of multi-component, multi-target, and multi-pathway synergistic effect in the treatment of OC, which provides a theoretical basis for in-depth research on the material basis, mechanism, and clinical application.

Effects of Danhong injection, a traditional Chinese medicine, on nine cytochrome P450 isoforms in vitro.

Danhong injection (DHI) is made from Salvia miltiorrhiza Bunge. and Carthamus tinctorius L. extract and is widely used in the clinical treatment of cardiovascular and cerebrovascular diseases. This study aimed to evaluate the effect of DHI on cytochrome P450 (CYP450) enzymes in vitro to predict drug-drug interactions based on CYP450 as combination therapy. To assess the inhibitory effect of DHI on CYP450, we detected the IC50 value of DHI on CYP450 in vitro by liquid chromatography/tandem mass spectrometry (LC-MS/MS). Simultaneously, the induction effect of DHI on CYP450s was also evaluated. The relative induction ratios of DHI on CYP1A2, CYP2B6 and CYP3A4 activity were calculated by LC-MS/MS. The expression level of CYP3A4 mRNA was determined by reverse transcription PCR (RT-PCR). The LC-MS/MS data showed DHI intensively inhibit CYP2A6 activity and the intensity of inhibition was followed by CYP2C8, CYP3A4, CYP2C19, CYP2B6, CYP2D6, CYP1A2, CYP2E1 and CYP2C9 in vitro. The results of RT-PCR showed that there is a certain induction of DHI on CYP3A4 mRNA in human primary hepatocytes in vitro. The study suggested that drug-drug interactions might occur in clinical co-administration of drugs owing to the CYP2A6 inhibition and CYP3A4 induction.

Effects of diosmetin on nine cytochrome P450 isoforms, UGTs and three drug transporters in vitro.

Diosmetin (3', 5, 7-trihydroxy-4'-methoxyflavone), a natural flavonoid from traditional Chinese herbs, has been used in various medicinal products because of its anticancer, antimicrobial, antioxidant, estrogenic and anti-inflammatory activity. However, flavonoids could affect the metabolic enzymes and cause drug-drug interactions (DDI), reducing the efficacy of co-administered drugs and potentially resulting in serious adverse reactions. To evaluate its potential to interact with co-administered drugs, the IC50 value of phase I cytochrome P450 enzymes (CYPs), phase II UDP-glucuronyltransferases (UGTs) and hepatic uptake transporters (organic cation transporters (OCTs), organic anion transporter polypeptides (OATPs) and Na+-taurocholate cotransporting polypeptides (NTCPs)) were examined in vitro by LC-MS/MS. Diosmetin showed strong inhibition of CYP1A2 in a concentration-dependent manner. The intensity of the inhibitory effect was followed by CYP2C8, CYP2C9, CYP2C19 and CYP2E1. For CYP2A6, CYP2B6, CYP2D6 and CYP3A4, diosmetin was found to have no significant inhibitory effects, and the induction effect on CYPs was not significant. For UGTs, diosmetin had a minimal inhibitory effect. In addition, the inhibitory effects of diosmetin on OATP and OCT1 were weak, and it had little effect on NTCP. This finding indicated that drug-drug interactions induced by diosmetin may occur through co-administration of drugs metabolized by CYP1A2.

Pim-2 Modulates Aerobic Glycolysis and Energy Production during the Development of Colorectal Tumors.

Tumor cells have higher rates of glucose uptake and aerobic glycolysis to meet energy demands for proliferation and metastasis. The characteristics of increased glucose uptake, accompanied with aerobic glycolysis, has been exploited for the diagnosis of cancers. Although much progress has been made, the mechanisms regulating tumor aerobic glycolysis and energy production are still not fully understood. Here, we demonstrate that Pim-2 is required for glycolysis and energy production in colorectal tumor cells. Our results show that Pim-2 is highly expressed in colorectal tumor cells, and may be induced by nutrient stimulation. Activation of Pim-2 in colorectal cells led to increase glucose utilization and aerobic glycolysis, as well as energy production. While knockdown of Pim-2 decreased energy production in colorectal tumor cells and increased their susceptibility to apoptosis. Moreover, the effects of Pim-2 kinase on aerobic glycolysis seem to be partly dependent on mTORC1 signaling, because inhibition of mTORC1 activity reversed the aerobic glycolysis mediated by Pim-2. Our findings suggest that Pim-2-mediated aerobic glycolysis is critical for monitoring Warburg effect in colorectal tumor cells, highlighting Pim-2 as a potential metabolic target for colorectal tumor therapy.

A sensitive and high-throughput LC-MS/MS method for inhibition assay of seven major cytochrome P450s in human liver microsomes using an in vitro cocktail of probe substrates.

A sensitive and high-throughput LC-MS/MS method was established and validated for the simultaneous quantification of seven probe substrate-derived metabolites (cocktail assay) for assessing the in vitro inhibition of cytochrome P450 (CYP) enzymes in pooled human liver microsomes. The metabolites acetaminophen (CYP1A2), hydroxy-bupropion (CYP2B6), n-desethyl-amodiaquine (CYP2C8), 4'-hydroxy-diclofenac (CYP2C9), 4'-hydroxy-mephenytoin (CYP2C19), dextrorphan (CYP2D6) and 1'-hydroxy-midazolam (CYP3A4/5), together with the internal standard verapamil, were eluted on an Agilent 1200 series liquid chromatograph in <7 min. All metabolites were detected by an Agilent 6410B tandem mass spectrometer. The concentration of each probe substrate was selected by substrate inhibition assay that reduced potential substrate interactions. CYP inhibition of seven well-known inhibitors was confirmed by comparing a single probe substrate assay with cocktail assay. The IC50 values of these inhibitors determined on this cocktail assay were highly correlated (R(2) > 0.99 for each individual probe substrate) with those on single assay. The method was selective and showed good accuracy (85.89-113.35%) and between-day (RSD <13.95%) and within-day (RSD <9.90%) precision. The sample incubation extracts were stable at 25 °C for 48 h and after three freeze-thaw cycles. This seven-CYP inhibition cocktail assay significantly increased the efficiency of accurately assessing compounds' potential inhibition of the seven major CYPs in drug development settings.

In vitro inhibitory effects of scutellarin on six human/rat cytochrome P450 enzymes and P-glycoprotein.

Inhibition of cytochrome P450 (CYP) and P-glycoprotein (P-gp) are regarded as the most frequent and clinically important pharmacokinetic causes among the various possible factors for drug-drug interactions. Scutellarin is a flavonoid which is widely used for the treatment of cardiovascular diseases. In this study, the in vitro inhibitory effects of scutellarin on six major human CYPs (CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) and six rat CYPs (CYP1A2, CYP2C7, CYP2C11, CYP2C79, CYP2D4, and CYP3A2) activities were examined by using liquid chromatography-tandem mass spectrometry. Meanwhile, the inhibitory effects of scutellarin on P-gp activity were examined on a human metastatic malignant melanoma cell line WM-266-4 by calcein-AM fluorometry screening assay. Results demonstrated that scutellarin showed negligible inhibitory effects on the six major CYP isoenzymes in human/rat liver microsomes with almost all of the IC50 values exceeding 100 µM, whereas it showed values of 63.8 µM for CYP2C19 in human liver microsomes, and 63.1 and 85.6 µM for CYP2C7 and CYP2C79 in rat liver microsomes, respectively. Scutellarin also showed weak inhibitory effect on P-gp. In conclusion, this study demonstrates that scutellarin is unlikely to cause any clinically significant herb-drug interactions in humans when co-administered with substrates of the six CYPs (CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) and P-gp.

Evaluation of the pharmacokinetics and cardiotoxicity of doxorubicin in rat receiving nilotinib.

Doxorubicin (DOX) is a potent chemotherapy drug with a narrow therapeutic window. Nilotinib, a small-molecule Bcr-Abl tyrosine kinase inhibitor, was reported to reverse multidrug resistance (MDR) mediated by P-glycoprotein (P-gp) transmembrane transporters. The present study aimed to investigate nilotinib's affection on the steady-state pharmacokinetics, disposition and cardiotoxicity of DOX. A total of 24 male Sprague-Dawley rats were randomized into four groups (6 in each) and received the following regimens: saline, intravenous DOX (5mg/kg) alone, and DOX co-administrated with either 20 or 40mg/kg nilotinib. Blood was withdrawn at 12 time points till 72h after DOX injection and the concentrations of DOX and its metabolite doxorubicinol (DOXol) in serum and cardiac tissue were assayed by LC-MS-MS method. To determine the cardiotoxicity, the following parameters were investigated: creatine kinase, lactate dehydrogenase, malondialdehyde, and superoxide dismutase. Histopathological examination of heart section was carried out to evaluate the extent of cardiotoxicity after treatments. The results showed that pretreatment of 40mg/kg nilotinib increased the AUC0-t and Cmax of DOX and DOXol. However, their accumulation in cardiac tissue was significantly decreased when compared with the group that received DOX alone. In addition, biochemical and histopathological results showed that 40mg/kg nilotinib reduced the cardiotoxicity induced by DOX administration. In conclusion, co-administration of nilotinib increased serum exposure, but significantly decreased the accumulation of DOX in cardiac tissue. Consistent with in vitro profile, oral dose of 40mg/kg nilotinib significantly decreased the cardiotoxicity of DOX in rat by enhancing P-gp activity in the heart.

Tongguanteng injection reverses paclitaxel resistance via upregulation of TAB1 expression in ovarian cancer in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Tongguanteng injection (TGT), the water extract from the stem of the Traditional Chinese hebal medicine of Marsdenia tenacissima (Roxb.) Wight et Arn. has been used as anticancer remedy for decades. TGT was not only used in the treatment of many malignant cancers extensively, but also an adjuvant anticancer drug with chemotherapeutics clinically. AIM OF THE STUDY: To evaluate the effects of TGT on reversing paclitaxel (PTX) resistance and investigate the potential mechanism related to TAB1 in ovarian cancer (OC) in vitro and in vivo. MATERIALS AND METHODS: The synergistic effect and reversal ratio were determined by CCK8 assay and median-effect principle after the combination of TGT and PTX in OC A2780 and its PTX-resistant (A2780/T) cells. The biological functions in cell apoptosis, migration and invasion of A2780/T cells treated by PTX 4 µM with TGT 20, 40, 80 mg⋅mL-1 for 24 h were evaluated by colony formation, flow cytometry, wound healing and transwell assays. Proteomics technique and bioinformatic analysis were used to indentify the change of TAB1 expression in A2780/T cells induced by TGT. The association between TAB1 expression and human OC was analyzed by gene expression databases. In A2780/T cells, western blotting and colony formation assays were used to investigate the relationship between TAB1 expression and PTX resistance after TAB1 overexpression by TAB1 plasmids. The mechanism of TGT and PTX regulating TAB1 and its related proteins were explored by western blotting and flow cytometry assays after TAB1 knock-down using siTAB1. Moreover, TUNEL staining, immunohistochemistry (IHC) and histopathology were used to observe the antitumor effects, TAB1 and p-p38 expression and the tissues impairments in nude mice xenograft model established by A2780/T cells after the co-treatment with TGT and PTX by in vivo. RESULTS: TGT combined with PTX showed the synergistic effect (CI<1), which could reverse the IC50 values of PTX in OC A2780 and A2780/T cells about 23.50 and 6.44 times, respectively. Besides, TGT combined with PTX could significantly inhibit the migration, invasion and promote apoptosis of A2780/T cells. We identified that TGT could induce TAB1 expression in A2780/T cells by proteomics analysis. TAB1 downregulation was significantly associated with tumorigenesis and poor prognosis in OC patients and PTX resistance in A2780/T cells. Furthermore, TGT could activate TAB1/TAK1/p38 MAPK signaling pathway targeting TAB1 and regulate the expression of Bax, Bcl-2 proteins to improve the sensitivity of A2780/T cells to PTX. TGT combined with PTX also showed a greater inhibition in tumor growth than PTX monotherapy in vivo. These promising results show the efficacy of TGT in reversing PTX resistance and provide a potential strategy that targeting TAB1/TAK1/p38 MAPK signaling pathway may improve the chemotherapy sensitivity in OC. CONCLUSIONS: Our results revealed that Tongguanteng injection could reverse paclitaxel resistance and the potential mechanism might be associated with the activation of TAB1/TAK1/p38 MAPK signaling pathway in OC in vitro and in vivo. TAB1 might be a pivotal target for reversing PTX resistance. This study will provide a theoretical basis for the combination of Tongguanteng injection and paclitaxel in clinic.

In vitro inhibition of Huanglian [Rhizoma coptidis (L.)] and its six active alkaloids on six cytochrome P450 isoforms in human liver microsomes.

Huanglian (Rhizoma Coptidis) as a popular herb has been used for the treatment of various diseases such as diarrhea, eye inflammation and women's abdominal ailments. Alkaloids are considered to be responsible for its pharmacological effects. In this investigation, Huanglian and its six alkaloids (coptisine, epiberberine, berberine, jateorrhizine, palmatine and magnoflorine) were systematically evaluated for their inhibition of six cytochrome P450 isoforms (CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP3A4) in human liver microsomes by the LC-MS/MS method. Huanglian showed the strongest inhibition of CYP2D6, followed by CYP1A2 and CYP3A4_T. The IC50 values were 5.8 µg/mL, 36.8 µg/mL and 59.2 µg/mL, respectively. Of the constituents tested, coptisine and epiberberine showed strong inhibition of CYP2D6 with IC50 values of 4.4 µM and 7.7 µM; berberine, jateorrhizine and palmatine showed weak inhibition of CYP2D6 with IC50 values of 45.5 µM, 49.4 µM and 92.6 µM, respectively; jateorrhizine showed moderate inhibition of CYP3A4_T with an IC50 value of 13.3 µM; coptisine showed weak inhibition of CYP1A2 with an IC50 value of 37.3 µM. In addition, activation was observed in coptisine/CYP2C9 and palmatine/CYP2C9/CYP2C19. Other CYP450 isoforms were not affected markedly by the six alkaloids. In conclusion, Huanglian showed in vitro inhibition of CYP2D6, the inhibition might be contributed mostly by protoberberine alkaloids, especially coptisine and epiberberine. Herb-drug interactions may occur through the CYP2D6 inhibition.

Xiaoaiping injection enhances paclitaxel efficacy in ovarian cancer via pregnane X receptor and its downstream molecules.

ETHNOPHARMACOLOGICAL RELEVANCE: Xiaoaiping injection, a traditional Chinese medical injection extracted from root of Marsdenia tenacissima (Roxb.) Moon, has been exclusively used on curing malignant tumor in China and as adjuvant therapeutic agent for chemotherapeutics, including paclitaxel. AIM OF THE STUDY: The goal of this study was to investigate the synergistic inhibitory efficacy of Xiaoaiping injection and paclitaxel on ovarian cancer. The mechanism may be associated with nuclear receptor pregnane X receptor (PXR) regulating its downstream molecules. MATERIALS AND METHODS: In vitro, MTT assay, flow cytometry and Hoechst dyeing were used to evaluate the SK-OV-3 cell proliferation, apoptosis and cell cycle respectively. The mRNA and protein expression of PXR and its downstream CYP450 enzymes, transporters and Bcl-2 families were measured by qRT-PCR and Western blot. Rhodamine 123 efflux experiment was conducted to detect the P-gp efflux ability. PXR plasmid and PXR siRNA were transiently transfected into SK-OV-3 cells respectively to establish PXR-overexpressed or PXR-interfered cells. In vivo, xenograft tumor mice model was established by SK-OV-3 cells to estimate the antitumor effect of Xiaoaiping injection combined with paclitaxel. The expressions of PXR and its downstream molecules in tumor tissues were determined to further clarify the potential mechanism. RESULTS: Xiaoaiping injection significantly enhanced the anti-proliferation, pro-apoptosis effect of paclitaxel on SK-OV-3 cells. The synergetic effect was displayed by Xiaoaiping injection inhibiting paclitaxel-induced PXR and CAR expression, which subsequently inhibited CYP450 enzymes CYP2C8 and CYP3A4, transporter P-gp and anti-apoptotic proteins Bcl-2 and Bcl-xl in SK-OV-3 cells. In PXR-overexpressed cells, Xiaoaiping injection down-regulated the expression of PXR and its downstream molecules. The result of xenograft tumor model showed that Xiaoaiping injection combined with paclitaxel enhanced anti-tumor effect on ovarian cancer in vivo. CONCLUSIONS: Xiaoaiping injection enhances anti-tumor effect of paclitaxel by inhibiting cell proliferation, inducing apoptosis process. The mechanism may be associated with Xiaoaiping injection inhibiting PXR and its downstream metabolic enzymes CYP2C8, CYP3A4, transporter P-gp and anti-apoptosis protein Bcl-2.

Effect of Xiao-Ai-Ping injection on paclitaxel pharmacokinetics in rats by LC-MS/MS method.

Xiao-Ai-Ping injection (XAP) has been shown to be clinically effective in treatment of gastric carcinoma, liver cancer and lung cancer, when it was combined with anticancer drug paclitaxel (PTX). To analyze the effect of XAP on the pharmacokinetics of PTX, a liquid chromatography-tandem mass spectroscopy (LCMS/MS) assay method was developed and validated to quantify PTX simultaneously and its main metabolite 3'-p-hydroxypaclitaxel (C3'-OHP) in rat plasma. PTX and C3'-OHP were quantified using positive MRM mode. The analysis method was validated for specificity, recovery, carry-over, accuracy, precision, sample stability and dilution integrity under various storage conditions. The pharmacokinetic parameters were determined in rats after tail intravenous administration of 6 mg/mL PTX in the absence (control group) or presence of intraperitoneal administration of 10 mL/kg、20 mL/kg XAP (study groups). Compared to control group, the area under the plasma concentration-time curve (AUC) of PTX and C3'-OHP in study groups increased significantly following consecutive administration with XAP for 10 days. In conclusion, pretreatment with XAP enhanced the exposure of PTX and C3'-OHP. There would be herb-drug interaction happening between XAP and PTX in rats.

Serum and urine metabolomics study reveals a distinct diagnostic model for cancer cachexia.

BACKGROUND: Cachexia is a multifactorial metabolic syndrome with high morbidity and mortality in patients with advanced cancer. The diagnosis of cancer cachexia depends on objective measures of clinical symptoms and a history of weight loss, which lag behind disease progression and have limited utility for the early diagnosis of cancer cachexia. In this study, we performed a nuclear magnetic resonance-based metabolomics analysis to reveal the metabolic profile of cancer cachexia and establish a diagnostic model. METHODS: Eighty-four cancer cachexia patients, 33 pre-cachectic patients, 105 weight-stable cancer patients, and 74 healthy controls were included in the training and validation sets. Comparative analysis was used to elucidate the distinct metabolites of cancer cachexia, while metabolic pathway analysis was employed to elucidate reprogramming pathways. Random forest, logistic regression, and receiver operating characteristic analyses were used to select and validate the biomarker metabolites and establish a diagnostic model. RESULTS: Forty-six cancer cachexia patients, 22 pre-cachectic patients, 68 weight-stable cancer patients, and 48 healthy controls were included in the training set, and 38 cancer cachexia patients, 11 pre-cachectic patients, 37 weight-stable cancer patients, and 26 healthy controls were included in the validation set. All four groups were age-matched and sex-matched in the training set. Metabolomics analysis showed a clear separation of the four groups. Overall, 45 metabolites and 18 metabolic pathways were associated with cancer cachexia. Using random forest analysis, 15 of these metabolites were identified as highly discriminating between disease states. Logistic regression and receiver operating characteristic analyses were used to create a distinct diagnostic model with an area under the curve of 0.991 based on three metabolites. The diagnostic equation was Logit(P) = -400.53 - 481.88 × log(Carnosine) -239.02 × log(Leucine) + 383.92 × log(Phenyl acetate), and the result showed 94.64% accuracy in the validation set. CONCLUSIONS: This metabolomics study revealed a distinct metabolic profile of cancer cachexia and established and validated a diagnostic model. This research provided a feasible diagnostic tool for identifying at-risk populations through the detection of serum metabolites.

Scutellarin protects against doxorubicin-induced acute cardiotoxicity and regulates its accumulation in the heart.

The clinical use of doxorubicin (DOX) is limited by its dose-dependent cardiotoxicity. The present study investigated the effects of scutellarin against DOX-induced cardiotoxicity in rats using pharmacodynamic and pharmacokinetic approaches. DOX (20 mg/kg) was injected intraperitoneally (i.p.) as a single dose, and scutellarin (5 mg/kg/day) was injected intravenously (i.v.) for 3 days. Rats treated with DOX showed acute cardiotoxicity as indicated by the elevated serum lactate dehydrogenase (LDH) activity (4057.8 ± 107.2 vs. 2032.7 ± 70.95), tissue malondialdehyde (MDA) level (2.083 ± 0.10 vs. 1.103 ± 0.09), cardiac troponin T (cTnT) concentration (0.1695 ± 0.0114 ng/mL), the decreased left ventricular ejection fraction (LVEF) (47.75 ± 15.79 vs. 78.72 ± 7.25) and left ventricular fractional shortening (LVFS) (20.66 ± 8.06 vs. 43.7 ± 6.76) compared with those of the control group. Cotreatment with scutellarin significantly decreased the LDH activity (2595.9 ± 72.73), MDA level (1.380 ± 0.06), cTnT concentration (0.0222 ± 0.0041 ng/m L), increased LVEF (76.70 ± 3.91) and LVFS (40.28 ± 3.68). Histopathological studies showed disruption of cardiac tissues in the DOX groups. Cotreatment with scutellarin reduced the damage to cardiac tissues. In the pharmacokinetic and tissue distribution study, scutellarin reduced the heart tissue exposure to DOX but did not change the AUC of plasma. These results suggest that scutellarin can protect against DOX-induced acute cardiotoxicity through its antioxidant activity and alterations of heart concentrations.

Nilotinib reverses ABCB1/P-glycoprotein-mediated multidrug resistance but increases cardiotoxicity of doxorubicin in a MDR xenograft model.

The BCR-Abl tyrosine kinase inhibitor (TKI), nilotinib, was developed to surmount resistance or intolerance to imatinib in patients with Philadelphia-positive chronic myelogenous leukemia. Recent studies have shown that nilotinib induces potent sensitization to anticancer agents by blocking the functions of ABCB1/P-glycoprotein (P-gp) in multidrug resistance (MDR). However, changes in P-gp expression or function affect the cardiac disposition and prolong the presence of both doxorubicin (DOX) and doxorubicinol (DOXol) in cardiac tissue, thus, enhancing the risk of cardiotoxicity. In this study, we used a MDR xenograft model to evaluate the antitumor activity, tissue distribution and cardiotoxicity of DOX when co-administered with nilotinib. This information will provide more insight into the pharmacological role of nilotinib in MDR reversal and the risk of DOX cardiotoxicity. Our results showed that nilotinib significantly enhanced DOX cytotoxicity and increased intracellular rhodamine 123 accumulation in MG63/DOX cells in vitro and strongly enhanced DOX inhibition of growth of P-gp-overexpressing MG63/DOX cell xenografts in nude mice. Additionally, nilotinib significantly increased DOX and DOXol accumulation in serum, heart, liver and tumor tissues. Importantly, nilotinib induced a disproportionate increase in DOXol in cardiac tissue. In the co-administration group, CBR1 and AKR1A1 protein levels were significantly increased in cardiac tissue, with more severe necrosis and vacuole formation. These results indicate that nilotinib reverses P-gp- mediated MDR by blocking the efflux function and potentiates DOX-induced cardiotoxicity. These findings represent a guide for the design of future clinical trials and studies of pharmacokinetic interactions and may be useful in guiding the use of nilotinib in combination therapy of cancer in clinical practice.

Evaluation of impact of Herba Erigerontis injection, a Chinese herbal prescription, on rat hepatic cytochrome P450 enzymes by cocktail probe drugs.

ETHNOPHARMACOLOGICAL RELEVANCE: Herba Erigerontis injection (HEI), one of the most popular herbal prescription in China, is made from the aqueous extracts of Erigeron breviscapus whole plant. Now HEI is widely used for the treatment of cardiovascular diseases and cerebrovascular diseases such as coronary heart disease, anginapectoris and paralysis. AIM OF THE STUDY: The purpose of this study was to investigate the in vivo effect of HEI on rat cytochrome P450 enzymes (CYP1A2, CYP2C11, CYP2D4, CYP2E1 and CYP3A2) to assess its safety through its potential to interact with co-administered drugs. MATERIALS AND METHODS: Rats were randomly divided into five groups. Rats were intravenous administrated with HEI via the caudal vein at the dosage of 1.8ml/kg or 7.2ml/kg once daily for consecutive 3 days or 14 days. On the fourth or the fifteenth day, a cocktail solution at a dose of 5ml/kg, which contained caffeine (2.5mg/kg), tolbutamide (2.5mg/kg), chlorzoxazone (5mg/kg), midazolam (5mg/kg) and metoprolol (10mg/kg), was injected via the lingual vein to all rats. Then 0.8ml blood samples were collected at a set of time-points. The plasma concentrations of probe drugs were simultaneously determined by HPLC. Pharmacokinetic parameters simulated by DAS software were used for the evaluation of HEI on the activities of rat CYP1A2, CYP2C11, CYP2D4, CYP2E1 and CYP3A2 enzymes. ANOVA and Dunnett's test was used for data analysis. RESULTS: There were no significant influence of pharmacokinetic parameters of caffeine, tolbutamide and chlorzoxazone in HEI pretreated rats. But many pharmacokinetic parameters of metoprolol and midazolam in HEI pretreated rats were affected significantly (P<0.05), which indicated that metabolism of metoprolol and midazolam in these treatment groups was evidently slowed down. CONCLUSIONS: The results from the present in vivo study suggested that HEI showed no effects on rat CYP1A2, CYP2C11 and CYP2E1, however, it demonstrated potential inhibitory effects on rat CYP2D4 and CYP3A2. Therefore, caution is needed when HEI is co-administered with drugs metabolized by human CYP2D6 or CYP3A4 in clinic, which may result in increased concentrations of these drugs and relevant herb-drug interactions.

Inhibitory effects of limonin on six human cytochrome P450 enzymes and P-glycoprotein in vitro.

Among the various possible causes for drug interactions, pharmacokinetic factors such as inhibition of drug-metabolizing enzymes and transporters, especially cytochrome P450 (CYP) isoenzymes and P-glycoprotein (P-gp), are regarded as the most frequent and clinically important. Limonin is a widely used dietary supplement and one of the most prevalent citrus limonoids, which are known to have inhibitory effects on CYPs and P-gp. In this study, the in vitro inhibitory effects of limonin on the major human CYP isoenzymes (CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) activities in human liver microsomes were examined using liquid chromatography-tandem mass spectrometry. The inhibitory effects of limonin on P-gp activity in a human metastatic malignant melanoma cell line WM-266-4 were examined using a calcein-AM fluorometry screening assay. It demonstrates that limonin has negligible inhibitory effects on human CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and P-gp. However, potent inhibition of CYP3A4 by limonin is observed with IC50 values of 6.20 µM (CYP3A4/testosterone) and 19.10 µM (CYP3A4/midazolam). This finding has important implications with regard to food-drug interactions between limonin and several narrow therapeutic index drugs that are metabolized by CYP3A4.