Quanjun Yang

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.

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.

Adenovirus-mediated expression of orphan nuclear receptor NR4A2 targeting hepatic stellate cell attenuates liver fibrosis in rats.

Liver fibrosis is a wound-healing response characterized with the accumulation of extracellular matrix (ECM). And hepatic stellate cells (HSCs) are the principal cell source of ECM. NR4A2 (Nurr1) is a member of orphan nuclear receptor NR4A family and acts as transcription factor. It participates in regulating cell differentiation, proliferation and apoptosis. We previously demonstrated that NR4A2 expression in fibrotic liver reduced significantly compared with normal liver and NR4A2 knockout in HSCs promoted ECM production. In the present study we explored the role of NR4A2 on liver fibrosis. Studies in cultured HSCs demonstrated that NR4A2 over-expression suppressed the activation of HSCs, such as ECM production and invasion ability. Moreover cell cycle was arrested, cell apoptosis was promoted and cell signaling pathway was influenced. Adenovirus-mediated delivery of NR4A2 in rats ameliorated significantly dimethylnitrosamine (DMN) induced liver fibrosis. The In vivo experiments produced results consistent with in vitro experiments. Taken together these results demonstrate NR4A2 enhancement attenuates liver fibrosis via suppressing the activation of HSCs and NR4A2 may be an ideal target for anti-fibrotic therapy.

The roles of apolipoprotein E3 and CYP2D6 (rs1065852) gene polymorphisms in the predictability of responses to individualized therapy with donepezil in Han Chinese patients with Alzheimer's disease.

AIM Polymorphisms in the apolipoprotein E and CYP2D6 genes are widely reported to be related to Alzheimers disease. However, few studies have focused on the relationship between polymorphisms in apolipoprotein E and CYP2D6 (rs1065852) genes and therapeutic responses to donepezil (DNP). This study explored the influence of apolipoprotein E3 and CYP2D6 (rs1065852) gene polymorphisms on therapeutic responses to donepezil in Han Chinese patients with Alzheimers disease. MATERIALS AND METHODS A total of 85 patients with mild to moderate Alzheimers disease who were treated with 2.5-10mg of DNP per day for at least 3 months were enrolled. Mini-Mental State Examination scores were measured before and after DNP treatment, and the apolipoprotein E3 and CYP2D6 (rs1065852) genotypes of the patients were determined. RESULTS We found that ApoE E3 non-carriers responded better to DNP treatment than E3 carriers (p=0.000) and that CYP2D6*10/*10 patients (MMSE score change: 0.29±3.27) exhibited better therapeutic responses to DNP than did CYP2D6*1/*1 and CYP2D6*1/*10 patients (p=0.033). Patients who were ApoE E3 non-carriers and who had the CYP2D6*10/*10 genotype exhibited a trend toward better clinical responses to DNP therapy. CONCLUSIONS The ApoE E3 allele and the CYP2D6 rs1065852 polymorphism may provide clinically relevant information for predicting therapeutic responses to DNP therapy.

Chinese Herbal Medicines as an Adjunctive Therapy for Unresectable Pancreatic Cancer: A Systematic Review and Meta-Analysis

Pancreatic cancer is a common malignancy with a high mortality. Most patients present clinically with advanced pancreatic cancer. Moreover, the effect of radiotherapy or chemotherapy is limited. Complementary and alternative medicines represent exciting adjunctive therapies. In this study, we ascertained the beneficial and adverse effects of Chinese herbal medicine (CHM) in combination with conventional therapy for inoperable pancreatic cancer by using meta-analysis methods for controlled clinical trials. We extracted data for studies searched from six electronic databases that were searched and also assessed the methodological quality of the included studies. We evaluated the following outcome measures: 6-month and 1-year survival rate, objective response rate, disease control rate, quality of life, and adverse effects. The final analysis showed CHM is a promising strategy as an adjunctive therapy to treat advanced or inoperable pancreatic cancer and that CHM in combination with conventional therapy is a promising strategy for resistant disease. However, convincing evidence must be obtained and confirmed by high-quality trials in future studies.

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 nilotinibs 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.

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

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.

ABCB1-overexpressing MG63/DOX cell xenograft model: maintain the MDR phenotype in vivo.

Abstract Context: Multi-drug resistance (MDR) constitutes a major obstacle in the effectiveness of chemotherapy. P-Glycoprotein (P-gp), the product of ABCB1 gene, is a transmembrane transporter that actively pumps cytotoxic drugs out of tumor cells resulting in MDR. Objective: We sought to establish an MG63/DOX cell xenografts model that maintained the MDR phenotype and molecular properties in vivo in order to screen for new P-gp inhibitors. Materials and methods: The cytotoxicities of doxorubicin, paclitaxel and cytarabine were evaluated by MTT assays. P-gp activity was measured by rhodamine 123 accumulation using flow cytometry. P-gp expression in MG63/DOX cells and tumor tissues was detected by western blotting and immunohistochemistry. Results: Our results showed that MG63/DOX cells exhibited 70-fold resistance to doxorubicin and more than 150-fold resistance to paclitaxel compared with parent MG63 cells. Furthermore, the ABCB1 inhibitor verapamil (10 μM) effectively reversed doxorubicin and paclitaxel resistance by 90- and 200-fold, respectively. The intracellular accumulation of rhodamine 123 was significantly increased (8.35-fold) in MG63/DOX cell, as compared to MG63 cells, in the presence of 10 μM verapamil. MG63/DOX tumor chunk xenografts had a high formation rate (88%). Finally, we found that the ABCB1 gene was overexpressed in different generations of solid tumors. Discussion and conclusion: These data demonstrated that MG63/DOX tumor chunk subculture in vivo retained their molecular properties. This model could serve as a convenient system for the preclinical investigation of drug combinations and the screening of new agents to reverse ABCB1-mediated MDR.

Acetylcholinesterase inhibitor donepezil effects on plasma β-hydroxybutyrate levels in the treatment of Alzheimer's disease.

BACKGROUND Alzheimers disease (AD) is a complex neurodegenerative disorder characterized by a multi-factorial etiology that is not completely understood. Donepezil is a first-line acetylcholinesterase inhibitor used for the treatment of AD that has been found, in addition to its potent acetylcholinesterase inhibitory effect, to act through other non-cholinergic mechanisms such as affecting mitochondrial biogenesis through peroxisome proliferator-activated receptor gamma coactivator (PGC1α). Mitochondrial biogenesis and PGC-1α, at least in part, are associated with hepatic fatty acid oxidation and ketogenesis. Whether donepezil regulates ketogenesis in AD treatment remains unclear. Ketogenesis is important in the progression of AD and is a critical consideration during the therapeutic strategy selection for AD. Thus, our goals were to determine the differences in ketone bodies in patients with AD who were taking donepezil treatment and those who were not, to elucidate the potential effect of AD and donepezil therapy on ketone body metabolic parameters, and to discover the effect of donepezil therapy on ketogenesis in patients with AD. METHODS Cross-sectional analysis was performed on plasma collected from 145 individuals, namely, elderly adults as healthy controls (n=30), newly diagnosed patients with AD (n=30), patients with AD who responded to donepezil therapy (n=48) and patients with AD who did not respond to donepezil therapy (n=37). Gas chromatography-mass spectrometry was performed to quantify the lipids in the plasma. The level of β-hydroxybutyrate, a metabolite, was determined by liquid chromatographytandem mass spectrometry, and to gain further insight into the effect of donepezil on ketogenesis, the effects of donepezil were investigated in a mouse model. RESULTS The level of β-hydroxybutyrate decreased in AD patients, and donepezil elevated the plasma level of β-hydroxybutyrate. Donepezil increased the plasma and liver levels of β-hydroxybutyrate in mice as well as the hepatic expression of PGC-1α and the mitochondrial expression of HMG-CoA synthetase 2 (HMGCS2) in response to fasting, causing a subsequent increase in ketogenesis. CONCLUSIONS Our study revealed that impaired ketogenesis is a metabolic feature of AD. Donepezil had effects on ketogenesis in mice and reversed the decrease in the level of β-hydroxybutyrate found in patients with AD.

Association between ABCA1 gene polymorphisms and the therapeutic response to donepezil therapy in Han Chinese patients with Alzheimer’s disease

AIM It is reported that ABCA1, which plays a key role in cholesterol transport and apolipoprotein E (APOE) metabolism in the brain, is related to Alzheimers disease. However, few studies have focused on the relationship between the ABCA1 gene and the therapeutic response to donepezil (DNP), which has been shown to be related to reduced sAPP production.This study evaluated the association between the ABCA1 gene polymorphism and the clinical response to donepezil therapy in Han Chinese patients with Alzheimers disease. METHODS We examined ABCA1 gene polymorphisms in 88 Han Chinese patients with Alzheimers disease who were receiving DNP therapy. The Mini-Mental State Examination was conducted before and after DNP treatment, and the ABCA1 rs 2230806 and rs 2230808, APOE E3 genotypes of each patient were identified. RESULTS We found that patients with the ABCA1 rs2230806 GG genotype responded better to DNP treatment compared to those with the AA and AG genotypes (p = 0.001). Patients who were APOE E3 non-carriers and had the ABCA1 rs2230806 GG genotype tended to have a better clinical response to DNP therapy. CONCLUSIONS The ABCA1 rs 2230806 polymorphism and its combination with the APOE E3 allele may provide clinically relevant information for predicting the therapeutic response to DNP therapy.