Comprehensive Zebrafish Water Tank Experiment for Metabolic Studies of Testolactone

Breaking the Bottleneck in Anticancer Drug Development: Efficient Utilization of Synthetic Biology

Natural products have multifarious bioactivities against bacteria, fungi, viruses, cancers and other diseases due to their diverse structures. Nearly 65% of anticancer drugs are natural products or their derivatives. Thus, natural products play significant roles in clinical cancer therapy. With the development of biosynthetic technologies, an increasing number of natural products have been discovered and developed as candidates for clinical cancer therapy. Here, we aim to summarize the anticancer natural products approved from 1950 to 2021 and discuss their molecular mechanisms. We also describe the available synthetic biology tools and highlight their applications in the development of natural products.

Medaka embryos as a model for metabolism of anabolic steroids

In anti-doping science, the knowledge of drug metabolism is a prerequisite to identify analytical targets for the detection of misused prohibited substances. As the most obvious way to study xenobiotic metabolism, the administration to human volunteers, faces ethical concerns, there is a need for model systems. In the present study, we investigated whether Oryzias latipes (medaka) embryos might be an alternative, non-animal test model to study human-like metabolism. In the present study, we exposed medaka embryos at the morula stage to the anabolic steroid metandienone (10 µM or 50 µM) for a period of 2 or 8 days. According to the fish embryo toxicity test (OECD test), we assessed the developmental status of the embryos. We further investigated metandienone metabolites by high-performance liquid chromatography- and gas chromatography-mass spectrometry. Medaka embryos produced three mono-hydroxylated and one reduced metabolite known from human biotransformation. Developmental malformations were observed for the exposition to 50 µM metandienone, while a significant elevation of the heart beat was also present in those individuals exposed to the lower dose for 8 days. The present study demonstrates that the medaka embryo represents a promising model to study human-like metabolism. Moreover, the judgement of developmental parameters of the fish embryos enables for the simultaneous assessment of toxicity.

Metabolic study of cafestol using in silico approach, zebrafish water tank experiments and liquid chromatography high-resolution mass spectrometry analyses

Coffee is one of the most consumed beverages worldwide. Cafestol is an endogenous coffee diterpene present in raw coffee beans and also found in hot beverages, with several biological activities. However, there is still little information on this molecule after ingestion of coffee infusion. Zebrafish (Danio rerio) is a promising in vivo model for metabolic studies due to the annotation of mammalian orthologs to encode enzymes related to drug metabolism. Experiments using Zebrafish Water Tank (ZWT) model produce more significant number of metabolites for molecular investigation in a cleaner matrix than other classical models, such as purified hepatocytes. This work aimed to investigate the biotransformation of cafestol by the ZWT model using ultra-performance liquid chromatography coupled to hybrid quadrupole-orbitrap high-resolution mass spectrometry equipped with electrospray ionization (UPLC-HRMS) supported by in silico approach using SMARTCyp, Way2Drug and XenoSite Softwares. Twenty-five metabolites of cafestol were proposed by in silico analysis, in which 5 phase I metabolites were confirmed in the ZWT by UPLC and MS/HRMS investigation: 6-hydroxy-cafestol, 6,12-dihydroxy-cafestol, 2-oxo-cafestol, 6-oxo-cafestol and one isomer whose position in the carboxyl group was not determined. These metabolites were observed during 9 h of the experiment, whose contents were associated with the behavioral responses of the fish.

Evaluation of fentanyl toxicity and metabolism using a zebrafish model

The increased abuse of novel drugs has created a critical need for cheap and rapid in vivo models to understand whole organism drug-induced toxicity and metabolic impacts. One such model is zebrafish, which share many similarities to human. Assays have been developed for behavioral, toxicity, and metabolism elucidation following chemical exposure. The zebrafish model provides the advantage of assessing these parameters within a single study. Previous zebrafish studies have evaluated the behavioral effects of fentanyl, but not developmental toxicity and its relation to metabolism. In this study, we evaluate the effects of fentanyl on the development of wild-type (TL strain) zebrafish and its metabolism over 4 days. Fertilized eggs were exposed to six concentrations of fentanyl (0.01, 0.1, 1, 10, 50, and 100 μM) through embryo media incubated at 28-29°C. Observations included egg coagulation, somite formation, heartbeat, tail and yolk morphology, pericardial formation, and swim bladder inflation. The incubation media was analyzed for the presence of metabolites using a targeted metabolomics approach. Fentanyl concentration caused significant effects on survival and development, with notable defects to the tail, yolk, and pericardium at 50 and 100 μM. Despropionyl fentanyl (4-ANPP), β-hydroxy fentanyl, and norfentanyl were detected in zebrafish larvae. We present a single in vivo model to assess toxicity and metabolism of fentanyl exposure in a vertebrate model system. Our findings provide a foundation for further investigations into fentanyl's mechanism of action and translation to human drug exposure.

Is zebrafish (Danio rerio) water tank model applicable for the assessment of glucocorticoids metabolism? The budesonide assessment

Knowledge of the metabolic profile is essential for doping control analysis in sport since most drugs are excreted after an elaborate biotransformation process. Currently, Zebrafish Water Tank (ZWT) model has been applied to investigate the metabolism of different doping agents. Nevertheless, the class of glucocorticoids has not been subjected to this model for metabolism studies. In the present work, budesonide (BUD) was applied as a pilot to investigate the metabolic pathways of glucocorticoids in the ZWT model. The BUD biotransformation in ZWT model was compared to the described metabolism in humans. Samples from ZWT experiments were collected after BUD administration and analyzed by Liquid Chromatography coupled to High Resolution Mass Spectrometry (LC-HRMS). Following the identification and characterization of all significant metabolites described for humans, it was observed that the ZWT was able to produce in a relevant amount the main target for doping control purposes: the 6β-hydroxy BUD. In addition, prior knowledge about the lack of butyrylcholinesterase activity in the zebrafish organism was considered for the evaluation for the formation of the 16α-hydroxy prednisolone, the most intense BUD metabolite in human urine. Biotransformation of BUD by ZWT focused on metabolites with the acetal fraction preserved, including the intermediate metabolite for the 16α-hydroxy prednisolone pathway. However,analternative metabolic pathway for the complete biotransformation of the 16α-hydroxy prednisolone intermediate was not observed, leading to the absence of the major human metabolite in the ZWT model. The findings reported in this study elucidate for the first time the application and limitations of the ZWT model to evaluate the metabolism of other glucocorticoids.

Annual banned-substance review: Analytical approaches in human sports drug testing 2019/2020

Analytical chemistry-based research in sports drug testing has been a dynamic endeavor for several decades, with technology-driven innovations continuously contributing to significant improvements in various regards including analytical sensitivity, comprehensiveness of target analytes, differentiation of natural/endogenous substances from structurally identical but synthetically derived compounds, assessment of alternative matrices for doping control purposes, and so forth. The resulting breadth of tools being investigated and developed by anti-doping researchers has allowed to substantially improve anti-doping programs and data interpretation in general. Additionally, these outcomes have been an extremely valuable pledge for routine doping controls during the unprecedented global health crisis that severely affected established sports drug testing strategies. In this edition of the annual banned-substance review, literature on recent developments in anti-doping published between October 2019 and September 2020 is summarized and discussed, particularly focusing on human doping controls and potential applications of new testing strategies to substances and methods of doping specified the World Anti-Doping Agency's 2020 Prohibited List.

Metabolism of synthetic cathinones through the zebrafish water tank model: a promising tool for forensic toxicology laboratories

Purpose

The aim of this study was to identify in vivo phase I metabolites of five psychoactive substances: N-ethylpentylone, ethylone, methylone, α-PVP and 4-CDC, using the in house developed experimental set-up zebrafish (Danio rerio) water tank (ZWT). High-resolution mass spectrometry allowed for metabolite identification. A pilot study of reference standard collection of N-ethylpentylone from the water tank was conducted.

Methods

ZWT consisted in 8 fish placed in a 200 mL recipient-containing water for a single cathinone. Experiments were performed in triplicate. Water tank samples were collected after 8 h and pretreated through solid-phase extraction. Separation and accurate-mass spectra of metabolites were obtained using liquid chromatography–high resolution tandem mass spectrometry.

Results

Phase I metabolites of α-PVP were identified, which were formed involving ketone reduction, hydroxylation, and 2″-oxo-pyrrolidine formation. The lactam derivative was the major metabolite observed for α-PVP in ZWT. N-Ethylpentylone and ethylone were transformed into phase I metabolites involving reduction, hydroxylation, and dealkylation. 4-CDC was transformed into phase I metabolites, reported for the first time, involving N-dealkylation, N,N-bis-dealkylation and reduction of the ketone group, the last one being the most intense after 8 h of the experiment.

Conclusions

ZWT model indicated to be very useful to study the metabolism of the synthetic cathinones, such as N-ethylpentylone, ethylone, α-PVP and 4-CDC. Methylone seems to be a potent CYP450 inhibitor in zebrafish. More experiments are needed to better evaluate this issue. Finally, this approach was quite simple, straightforward, extremely low cost, and fast for “human-like” metabolic studies of synthetic cathinones.