Interaction of isoflavonoids with human liver microsomal cytochromes P450: inhibition of CYP enzyme activities.

1. The possibility of interaction of isoflavonoids with concomitantly taken drugs to determined isoflavonoids safety was studied. Inhibition of nine forms of cytochrome P450 (CYP3A4, CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2C9, CYP2D6 and CYP2E1) by 12 isoflavonoids (daidzein, genistein, biochanin A, formononetin, glycitein, equol and six glucosides, daidzin, puerarin, genistin, sissotrin, ononin and glycitin) was studied systematically. 2. The most potent inhibitors were genistein and daidzein inhibiting noncompetitively the CYP2C9 with Ki of 35.95 ± 6.96 and 60.56 ± 3.53 µmol/l and CYP3A4 (inhibited by genistein with Ki of 23.25 ± 5.85 µmol/l also by a noncompetitive mechanism). Potent inhibition of CYP3A4 was observed also with biochanin A (Ki of 57.69 ± 2.36 µmol/l) and equol (Ki of 38.47 ± 2.32 µmol/l). 3. Genistein and daidzein inhibit noncompetitively CYP3A4 and CYP2C9. With plasma levels in micromolar range, a clinically important interaction with concomitantly taken drugs does not seem to be probable.

Acyclic nucleoside phosphonates: a study on cytochrome P450 gene expression.

1. Nucleotide analogues comprise an important class of drugs used in treatment of viral infections but also cancer. These drugs affect the structural integrity of DNA and activate different pathways and processes in the cell and may directly or indirectly influence the drug metabolizing system. Adefovir dipivoxil (AD) and tenofovir disoproxil (TD) are nucleotide analogues approved for the treatment of chronic hepatitis B and/or HIV/AIDS infection. 2. To evaluate the risk of their drug-drug interactions on the level of drug metabolism, an effect of both compounds on cytochromes P450 expression was studied using cDNA microarrays, real-time RT-PCR and immunoblotting. Mice were given intraperitoneally 25 mg/kg of AD or TD, respectively. As a positive control, a combination of prototypic cytochromes P450 (CYP) inducers, phenobarbital and ß-naphthoflavone was chosen. 3. The data obtained showed a significant CYP induction in the positive control group, but no clinically significant induction of CYP genes by AD or TD was observed. Our results support the evidence of safety of AD and TD with respect to drug-drug interactions based on enzyme induction. These findings are important as a plethora of new antivirals of different types are being tested and introduced to clinical practice, mostly to be used in combinations.

Development of the Czech Childhood Cancer Information System: Data Analysis and Interactive Visualization.

BACKGROUND: The knowledge of cancer burden in the population, its time trends, and the possibility of international comparison is an important starting point for cancer programs. A reliable interactive tool describing cancer epidemiology in children and adolescents has been nonexistent in the Czech Republic until recently. OBJECTIVE: The goal of this study is to develop a new web portal entitled the Czech Childhood Cancer Information System (CCCIS), which would provide information on childhood cancer epidemiology in the Czech Republic. METHODS: Data on childhood cancers have been obtained from the Czech National Cancer Registry. These data were validated using the clinical database of childhood cancer patients and subsequently combined with data from the National Register of Hospitalised Patients and with data from death certificates. These validated data were then used to determine the incidence and survival rates of childhood cancer patients aged 0 to 19 years who were diagnosed in the period 1994 to 2016 (N=9435). Data from death certificates were used to monitor long-term mortality trends. The technical solution is based on the robust PHP development Symfony framework, with the PostgreSQL system used to accommodate the data basis. RESULTS: The web portal has been available for anyone since November 2019, providing basic information for experts (ie, analyses and publications) on individual diagnostic groups of childhood cancers. It involves an interactive tool for analytical reporting, which provides information on the following basic topics in the form of graphs or tables: incidence, mortality, and overall survival. Feedback was obtained and the accuracy of outputs published on the CCCIS portal was verified using the following methods: the validation of the theoretical background and the user testing. CONCLUSIONS: We developed software capable of processing data from multiple sources, which is freely available to all users and makes it possible to carry out automated analyses even for users without mathematical background; a simple selection of a topic to be analyzed is required from the user.

Childhood cancer epidemiology in the Czech Republic (1994-2016).

BACKGROUND: The knowledge of cancer burden in the population, its time trends and the possibility of international comparison is an important starting point for cancer control programmes. Our study aimed to evaluate trends in childhood cancer epidemiology of patients aged 0-14 years in the period 1994-2016 in the Czech Republic. METHODS: Data on childhood cancers have been obtained from the Czech National Cancer Registry. These data were validated using the clinical database of childhood cancer patients and combined with data from death certificates. Incidence and mortality trends were assessed by the joinpoint regression method. The life tables method was used to calculate the overall age-standardised five-year survival. RESULTS: The incidence trend was stable; the age-standardised (world) cancer incidence - ASR (W) - was 173.7 per 1 million children in the period 1994-2016. However, there was apparent significant decrease in mortality: ASR (W) dropped from 58.1 per 1 million children in 1994 to 21.4 per 1 million children in 2016. The overall five-year survival increased over time by 10 %. Statistically significant improvements in survival were observed in patients with lymphoid leukaemia, astrocytomas, neuroblastomas, osteosarcomas and rhabdomyosarcomas. CONCLUSION: Such a relevant increase in survival rates, and therefore also a decrease in mortality rates in the Czech Republic, is most likely due to improvements in diagnostic and treatment methods since the 1990s, which were facilitated by the concentration of childhood cancer patients in children's cancer centres.

Comparison of Different Treatment Modalities Outcomes in Clinically Node-positive Bladder Cancer: Analysis of a Population-based Cancer Registry.

INTRODUCTION: Patients with clinically node-positive bladder cancer were historically considered to have uniformly poor prognosis and were frequently treated with palliative chemotherapy (CHT) only. Although retrospective data show that long-term survival with combined treatment (surgery + CHT) is possible in one-third of these patients, consensus on a treatment algorithm is still lacking. The aim of the study is to compare the efficacy of different treatment modalities based on data from a population-based cancer registry. PATIENTS AND METHODS: The study comprises 661 patients identified from the Czech National Cancer Registry (1996-2015) with cTanyN1-3M0 bladder cancer; 195 were treated with CHT alone, 234 underwent radical cystectomy alone (RC), and 232 received a combination of RC and perioperative CHT (RC + CHT). Multivariate Cox proportional hazard regression analyses were used to evaluate the effectiveness of various treatments. RESULTS: The 5-year OS for CHT alone, RC alone, and RC + CHT were 21.7% (95% confidence interval [CI], 15.4%-28.0%), 12.1% (95% CI, 7.4%-16.7%), and 25.4% (95% CI, 18.9%-31.9%), respectively (P < .001). The median survivals were 17, 10, and 23 months, respectively. In multivariate analysis, age > 60 years (hazard ratio, 1.29; 95% CI, 1.06-1.56; P = .011) and clinical stage cT3-4 (hazard ratio, 1.39; 95% CI, 1.12-1.71; P = .002) were negative predictors of survival. When compared with CHT, RC + CHT reduced the risk of overall mortality by 21% (P = .044). CONCLUSION: Approximately one-quarter of clinically node-positive patients may achieve long-term survival with combined treatment integrating RC and perioperative CHT. The overall survival of patients is significantly improved with a multimodal approach in comparison to CHT alone.

Effects of anthocyanidins and anthocyanins on the expression and catalytic activities of CYP2A6, CYP2B6, CYP2C9, and CYP3A4 in primary human hepatocytes and human liver microsomes.

Anthocyanidins and anthocyanins are pharmacologically active constituents of various berry fruits, such as blueberry and cranberry. These compounds are also contained in massively used nutritional supplements based on extracts or dry matter from berry fruits. The current study evaluated the effects of anthocyanidins and anthocyanins on the expression and catalytic activity of major drug-metabolizing enzymes CYP2C9, CYP2A6, CYP2B6, and CYP3A4 in primary cultures of human hepatocytes and human liver microsomes. Expression of mRNA was quantified by qRT-PCR. Expression of proteins was evaluated by Western blotting and immunochemiluminescence. The catalytic activity of CYP enzymes was measured by HPLC using specific enzyme substrates. Tested anthocyanidins (6) and anthocyanins (21) did not induce the expression of mRNA and protein of CYP2C9, CYP2A6, CYP2B6, and CYP3A4 genes in human hepatocytes. Catalytic activities of CYP2C9, CYP2A6, CYP2B6, and CYP3A4 enzymes were inhibited by all anthocyanidins to different extents (e.g., delphinidin inhibits CYP3A4 by >90% at 100 µM with IC50 = 32 µM). Of 21 anthocyanins tested, only cyanidin-3-O-rhamnoside (CYP3A4 by >75% at 100 µM with IC50 = 44 µM) and two glycosides of delphinidin significantly inhibited examined cytochromes P450. It may be concluded that in the ranges of common ingestion of either food or dietary supplement an induction or significant inhibition of CYP2C9, CYP2A6, CYP2B6, and CYP3A4 activity is most probably not expected.

Effects of anthocyanins on the AhR-CYP1A1 signaling pathway in human hepatocytes and human cancer cell lines.

Anthocyanins are plant pigments occurring in flowers and berry fruits. Since a phenomenon of food-drug interactions is increasingly emerging, we examined the effects of 21 major anthocyanins and the extracts from 3 food supplements containing anthocyanins on the aryl hydrocarbon receptor (AhR)-cytochrome P450 CYP1A1 signaling pathway in human hepatocytes and human hepatic HepG2 and intestinal LS174T cancer cells. Pelargonidin-3-O-rutinoside (PEL-2) and cyanidin-3,5-O-diglucoside (CYA-3) dose-dependently activated AhR, as revealed by gene reporter assay. PEL-2 and CYA-3 induced CYP1A1 mRNA but not protein in HepG2 and LS174T cells. Neither compounds induced CYP1A1 mRNA and protein in four different primary human hepatocytes cultures. The effects of PEL-2 and CYA-3 on AhR occurred by ligand-dependent and ligand-independent mechanisms, respectively, as demonstrated by ligand binding assay. In a direct enzyme inhibition assay, none of the antocyanins tested inhibited the CYP1A1 marker activity to less than 50% even at 100 µM concentration. PEL-2 and CYA-3 at 100 µM inhibited CYP1A1 to 79% and 65%, respectively. In conclusion, with exception of PEL-2 and CYA-3, there were no effects of 19 major anthocyanins and 3 food supplements containing anthocyanins on AhR-CYP1A1 signaling, implying zero potential of these compounds for food-drug interactions with respect to AhR-CYP1A1 pathway.