In vitro effects of European and Latin-American medicinal plants in CYP3A4 gene expression, glutathione levels, and P-glycoprotein activity.

Many medicinal plants species from European -such as Artemisia absinthium, Equisetum arvense, Lamium album, Malva sylvestris, Morus nigra, Passiflora incarnata, Frangula purshiana, and Salix alba- as well as Latin American traditions -such as Libidibia ferrea, Bidens pilosa, Casearia sylvestris, Costus spicatus, Monteverdia ilicifolia, Persea americana, Schinus terebinthifolia, Solidago chilensis, Syzygium cumini, Handroanthus impetiginosus, and Vernonanthura phosphorica- are shortlisted by the Brazilian National Health System for future clinical use. However, they lack many data on their action upon some key ADME targets. In this study, we assess non-toxic concentrations (up to100 µg/ml) of their infusions for in vitro ability to modulate CYP3A4 mRNA gene expression and intracellular glutathione levels in HepG2 cells, as well as P-glycoprotein (P-gp) activity in vincristine-resistant Caco-2 cells (Caco-2 VCR). We further investigated the activation of human pregnane X receptor (hPXR) in transiently co-transfected HeLa cells and the inhibition of Gamma-glutamyl transferase (GGT) in HepG2 cells. Our results demonstrate L. ferrea, C. sylvestris , M. ilicifolia, P. americana, S. terebinthifolia, S. cumini, V. phosphorica, E. arvense, P. incarnata, F. purshiana, and S. alba can significantly increase CYP3A4 mRNA gene expression in HepG2 cells. Only F. purshiana shown to do so likely via hPXR activation. P-gp activity was affected by L. ferrea, F. purshiana, S. terebinthifolia, and S. cumini. Total intracellular glutathione levels were significantly depleted by exposure to all extracts except S. alba and S. cumini This was accompanied by a lower GGT activity in the case of C. spicatus, P. americana, S. alba, and S. terebinthifolia, whilst L. ferrea, P. incarnata and F. purshiana increased it. Surprisingly, S. cumini aqueous extract drastically decreased GGT activity (-48%, p < 0.01). In conclusion, this preclinical study shows that the administration of some of these herbal medicines causes in vitro disturbances to key drug metabolism mechanisms. We recommend active pharmacovigilance for Libidibia ferrea (Mart.) L. P. Queiroz, Frangula purshiana Cooper, Schinus terebinthifolia Raddi, and Salix alba L. which were able to alter all targets in our preclinical study.

An in silico-in vitro pipeline for drug cardiotoxicity screening identifies ionic pro-arrhythmia mechanisms.

BACKGROUND AND PURPOSE: Before advancing to clinical trials, new drugs are screened for their pro-arrhythmic potential using a method that is overly conservative and provides limited mechanistic insight. The shortcomings of this approach can lead to the mis-classification of beneficial drugs as pro-arrhythmic. EXPERIMENTAL APPROACH: An in silico-in vitro pipeline was developed to circumvent these shortcomings. A computational human induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) model was used as part of a genetic algorithm to design experiments, specifically electrophysiological voltage clamp (VC) protocols, to identify which of several cardiac ion channels were blocked during in vitro drug studies. Such VC data, along with dynamically clamped action potentials (AP), were acquired from iPSC-CMs before and after treatment with a control solution or a low- (verapamil), intermediate- (cisapride or quinine) or high-risk (quinidine) drug. KEY RESULTS: Significant AP prolongation (a pro-arrhythmia marker) was seen in response to quinidine and quinine. The VC protocol identified block of IKr (a source of arrhythmias) by all strong IKr blockers, including cisapride, quinidine and quinine. The protocol also detected block of ICaL by verapamil and Ito by quinidine. Further demonstrating the power of the approach, the VC data uncovered a previously unidentified If block by quinine, which was confirmed with experiments using a HEK-293 expression system and automated patch-clamp. CONCLUSION AND IMPLICATIONS: We developed an in silico-in vitro pipeline that simultaneously identifies pro-arrhythmia risk and mechanism of ion channel-blocking drugs. The approach offers a new tool for evaluating cardiotoxicity during preclinical drug screening.

Effects of a new thyrotropic drug isolated from Potentilla alba on the male reproductive system of rats and offspring development.

BACKGROUND: The dysfunction of the thyroid gland is a common medical condition. Nowadays, patients frequently use medicinal herbs as complementary or alternative options to conventional drug treatments. These patients may benefit from treatment of thyroid dysfunctions with Potentilla alba L. preparations. While it has been reported that Potentilla alba preparations have low toxicity, nothing is known about their ability to affect reproductive functions in patients of childbearing age. METHODS: Male Wistar rats were orally treated with a thyrotrophic botanical drug, standardized Potentilla alba Dry Extract (PADE), at doses 8 and 40 times higher than the median therapeutic dose recommended for the clinical trials, for 60 consecutive days. Male Wistar rats receiving water (H2O) were used as controls. After completing treatment, half of the PADE-treated and control males were used to determine PADE gonadotoxicity, and the remaining half of PADE-treated and control males were mated with intact females. Two female rats were housed with one male for two estrus cycles. PADE effects on fertility and fetal/offspring development were evaluated. RESULTS: Herein, we report that oral treatment of male Wistar rats with PADE before mating with intact females instigated marked effects on male reproductive organs. Treatment significantly decreased the motility of the sperm and increased the number of pathological forms of spermatozoa. Additionally, a dose-dependent effect on Leydig cells was observed. However, these PADE effects did not significantly affect male fertility nor fetal and offspring development when PADE-treated males were mated with intact females. CONCLUSIONS: PADE treatment of male rates negatively affected sperm and testicular Leydig cell morphology. However, these changes did not affect male fertility and offspring development. It is currently not known whether PADE treatment may affect human male fertility and offspring development. Therefore, these results from an animal study need to be confirmed in humans. Results from this animal study can be used to model the exposure-response relationship and adverse outcomes in humans.

How Qualification of 3D Disease Models Cuts the Gordian Knot in Preclinical Drug Development.

Preclinical research struggles with its predictive power for drug effects in patients. The clinical success of preclinically approved drug candidates ranges between 3% and 33%. Regardless of the approach, novel disease models and test methods need to prove their relevance and reliability for predicting drug effects in patients, which is usually achieved by method validation. Nevertheless, validating all models appears unrealistic due to the variety of diseases. Thus, novel concepts are needed to increase the quality of preclinical research.Herein, we introduce qualification as a minimal standard to establish the relevance of preclinical models and test methods. Qualification starts with prioritizing and translating scientific requirements into technical parameters by quality function deployment. Qualified models use authenticated cells, which resemble the corresponding cells in humans in morphology and drug target expression. Moreover, disease models differ from normal models in the expression of relevant biomarkers. As a result, qualified test methods can discriminate effects of treatment standards and the effects of weakly effective or ineffective substances. Observer-blind readout, adequate data documentation, dropout inclusion, and a priori power studies are as crucial as realistic dosage regimens for qualified approaches. Here, we showcase the implementation of qualification. Adjusting the level of model complexity and qualification to three defined phases of preclinical research assures the optimal level of certainty at each step.In conclusion, qualification strengthens the researchers' impact by defining basic requirements that novel approaches must fulfill while still allowing for scientific creativity. Qualification helps to improve the predictive power of preclinical research. Applied to human cell-based models, qualification reduces animal testing, since only effective drug candidates are subjected to final animal testing and subsequently to clinical trials.

Technological Advances in Preclinical Drug Evaluation: The Role of -Omics Methods.

Preclinical drug development is an essential step in the drug development process where the evaluation of new chemical entities occurs. In particular, preclinical drug development phases include deep analysis of drug candidates' interactions with biomolecules/targets, their safety, toxicity, pharmacokinetics, metabolism by use of assays in vitro and in vivo animal assays. Legal aspects of the required procedures are well-established. Herein, we present a comprehensive summary of current state-of-the art approaches and techniques used in preclinical studies. In particular, we will review the potential of new, -omics methods and platforms for mechanistic evaluation of drug candidates and speed-up of the preclinical evaluation steps.

Discovery of Novel Therapeutics for Muscular Dystrophies using Zebrafish Phenotypic Screens.

The recent availability and development of mutant and transgenic zebrafish strains that model human muscular dystrophies has created new research opportunities for therapeutic development. Not only do these models mimic many pathological aspects of human dystrophies, but their small size, large clutch sizes, rapid ex utero development, body transparency, and genetic tractability enable research approaches that would be inconceivable with mammalian model systems. Here we discuss the use of zebrafish models of muscular dystrophy to rapidly screen hundreds to thousands of bioactive compounds in order to identify novel therapeutic candidates that modulate pathologic phenotypes. We review the justification and rationale behind this unbiased approach, including how zebrafish screens have identified FDA-approved drugs that are candidates for treating Duchenne and limb girdle muscular dystrophies. Not only can these drugs be re-purposed for treating dystrophies in a fraction of the time and cost of new drug development, but their identification has revealed novel, unexpected directions for future therapy development. Phenotype-driven zebrafish drug screens are an important compliment to the more established mammalian, target-based approaches for rapidly developing and validating therapeutics for muscular dystrophies.

Ethical issues on the "synthetic" phosphoethanolamine clinical trial / Questões éticas sobre o ensaio clínico da fosfoetanolamina "sintética"

Summary Notwithstanding its approval by the National Committee for Ethics in Research (Conep) on April 19, 2016, a trial of the so-called "synthetic" phosphoethanolamine (syn-phospho) pill in cancer patients raises ethical concerns. An analysis by a laboratory contracted by the Ministry of Science, Technology and Innovation (MCTI) revealed that syn-phospho contained a great amount of impurities and did not meet standards of pharmaceutical quality required for an investigational drug. Cytotoxicity against human tumor cell lines and in vivo rodent xenograft tumor assays consistently failed to demonstrate a potential anticancer activity of syn-phospho. Preclinical safety studies of syn-phospho were also insufficient to support a trial of this investigational drug in cancer patients. Moreover, the ethical approval decision apparently overlooked two previous findings that suggested a possible enhancement of mammary carcinoma cell proliferation by phosphoethanolamine, and an apparent increase in lung metastases (rat implanted tumor assay) by syn-phospho. The syn-phospho risk-benefit ratio is clearly unfavorable and, thus, this trial in cancer patients does not fulfill a key requirement to make a clinical research ethical. There are also concerns regarding whether the study design is robust enough (scientific validity), and the social value of the trial of syn-phospho in cancer patients is questionable.

Resumo Não obstante a sua aprovação pela Comissão Nacional de Ética em Pesquisa (Conep) em 19 de abril de 2016, um ensaio da pílula de fosfoetanolamina "sintética" (sin-fosfo) em pacientes com câncer levanta preocupações éticas. Uma análise feita por um laboratório contratado pelo Ministério da Ciência, Tecnologia e Inovação (MCTI) revelou que a sin-fosfo continha grande quantidade de impurezas e não satisfazia os padrões de qualidade farmacêutica exigidos para um medicamento experimental. Os ensaios de citotoxicidade com linhagens de células originárias de tumores humanos e testes in vivo em roedores com tumores xeno-enxertados falharam consistentemente em demonstrar uma potencial atividade anticâncer da sin-fosfo. Os estudos pré-clínicos de segurança da sin-fosfo também foram insuficientes para apoiar a realização de um ensaio desse medicamento experimental em pacientes com câncer. Além disso, a aprovação ética aparentemente desconsiderou dois achados anteriores, sugerindo uma possível exacerbação da proliferação de células de carcinoma de mama pela fosfoetanolamina, e um aparente aumento de metástases pulmonares (ensaio de tumores implantados em ratos) pela sin-fosfo. A relação risco-benefício é claramente desfavorável para a sin-fosfo e, portanto, esse ensaio em pacientes com câncer não atende um requisito essencial para que uma pesquisa clínica seja ética. Há também preocupações quanto ao delineamento do estudo ser suficientemente robusto (validade interna), e o valor social do ensaio da sin-fosfo em pacientes com câncer é questionável.

The Control of Drug Release and Vascular Endothelialization after Hyaluronic Acid-Coated Paclitaxel Multi-Layer Coating Stent Implantation in Porcine Coronary Restenosis Model

BACKGROUND AND OBJECTIVES: Hyaluronic acid (HA) is highly biocompatible with cells and the extracellular matrix. In contrast to degradation products of a synthetic polymer, degradation products of HA do not acidify the local environment. The aim of this study was to fabricate an HA-coated paclitaxel (PTX)-eluting stent via simple ionic interactions and to evaluate its effects in vitro and in vivo. MATERIALS AND METHODS: HA and catechol were conjugated by means of an activation agent, and then the stent was immersed in this solution (resulting in a HA-coated stent). After that, PTX was immobilized on the HA-coated stent (resulting in a hyaluronic acid-coated paclitaxel-eluting stent [H-PTX stent]). Study groups were divided into 4 groups: bare metal stent (BMS), HA, H-PTX, and poly (L-lactide)-coated paclitaxel-eluting stent (P-PTX). Stents were randomly implanted in a porcine coronary artery. After 4 weeks, vessels surrounding the stents were isolated and subjected to various analyses. RESULTS: Smoothness of the surface was maintained after expansion of the stent. In contrast to a previous study on a PTX-eluting stent, in this study, the PTX was effectively released up to 14 days (a half amount of PTX in 4 days). The proliferation of smooth muscle cells was successfully inhibited (by 80.5±12.11% at 7 days of culture as compared to the control) by PTX released from the stent. Animal experiments showed that the H-PTX stent does not induce an obvious inflammatory response. Nevertheless, restenosis was clearly decreased in the H-PTX stent group (9.8±3.25%) compared to the bare-metal stent group (29.7±8.11%). CONCLUSION: A stent was stably coated with PTX via simple ionic interactions with HA. Restenosis was decreased in the H-PTX group. These results suggest that HA, a natural polymer, is suitable for fabrication of drug-eluting stents (without inflammation) as an alternative to a synthetic polymer.

AZD3293: A Novel, Orally Active BACE1 Inhibitor with High Potency and Permeability and Markedly Slow Off-Rate Kinetics.

A growing body of pathological, biomarker, genetic, and mechanistic data suggests that amyloid accumulation, as a result of changes in production, processing, and/or clearance of brain amyloid-ß peptide (Aß) concentrations, plays a key role in the pathogenesis of Alzheimer's disease (AD). Beta-secretase 1 (BACE1) mediates the first step in the processing of amyloid-ß protein precursor (AßPP) to Aß peptides, with the soluble N terminal fragment of AßPP (sAßPPß) as a direct product, and BACE1 inhibition is an attractive target for therapeutic intervention to reduce the production of Aß. Here, we report the in vitro and in vivo pharmacological profile of AZD3293, a potent, highly permeable, orally active, blood-brain barrier (BBB) penetrating, BACE1 inhibitor with unique slow off-rate kinetics. The in vitro potency of AZD3293 was demonstrated in several cellular models, including primary cortical neurons. In vivo in mice, guinea pigs, and dogs, AZD3293 displayed significant dose- and time-dependent reductions in plasma, cerebrospinal fluid, and brain concentrations of Aß40, Aß42, and sAßPPß. The in vitro potency of AZD3293 in mouse and guinea pig primary cortical neuronal cells was correlated to the in vivo potency expressed as free AZD3293 concentrations in mouse and guinea pig brains. In mice and dogs, the slow off-rate from BACE1 may have translated into a prolongation of the observed effect beyond the turnover rate of Aß. The preclinical data strongly support the clinical development of AZD3293, and patients with AD are currently being recruited into a combined Phase 2/3 study to test the disease-modifying properties of AZD3293.

Concise review: drug discovery in the age of the induced pluripotent stem cell.

For decades, the paradigm of drug discovery and development has relied on immortalized cell lines, animal models of human disease, and clinical trials. With the discovery of induced pluripotent stem cell (iPSC) technology in 2007, a new human in vitro drug testing platform has potentially augmented this set of tools by providing additional ways to screen compounds for safety and efficacy. The growing number of human disease models made with patient-specific iPSCs has made it possible to conduct research on a wide range of disorders, including rare diseases and those with multifactorial origin, as well as to simulate drug effects on difficult-to-obtain tissues such as brain and cardiac muscle. Toxicity and teratogenicity assays developed with iPSC-derived cells can also provide an additional layer of safety before advancing drugs to clinical trials. The incorporation of iPSC technology into drug therapy development holds promise as a more powerful and nuanced approach to personalized medicine.

Use of optimized aminotransferase methods in regulated preclinical studies.

BACKGROUND: The serum activities of ALT and AST are key indicators of liver toxicity in the drug safety evaluation of laboratory animals and patients. To ensure that the full aminotransferase activity is measured, exogenous Pyridoxyl-5-Phosphate (P5P) cofactor is included in the assay reagent. Clinical pathology laboratories make a choice to use aminotransferase assays with or without the added P5P cofactor, and the impact of assay selection on safety assessment is not well understood. OBJECTIVES: The objective of this report was to investigate the effect of aminotransferase assay selection on the detection of liver toxicity based on a literature review. METHODS: Literature in public databases was searched using combinations of the search terms alanine aminotransferase, aspartate aminotransferase, pyridoxyl-5-phosphate, holoenzyme, apoenzyme, enzyme inhibition, artifact, clinical pathology, toxicology, and safety assessment. Regulations or guidance documents published by health authorities specifying clinical pathology evaluation in nonclinical and clinical safety studies of biopharmaceuticals, chemicals, and devices were also reviewed. RESULTS: Aminotransferase testing is not standardized in safety assessment studies and consequently, laboratories use aminotransferase assays with or without P5P cofactor. Individual studies have demonstrated mean differences of approximately 10-20% in serum ALT activity in animal and human populations. The impact of aminotransferase testing without P5P on detection of toxicity and decision-making in drug development has not been systematically evaluated. CONCLUSIONS: The use of different assays for measuring aminotransferase activity contributes to the variability in data between laboratories and studies. Standardizing aminotransferase assays is an avenue for improving the diagnostic performance in drug safety evaluation.

Sequence-Dependent Radiosensitization of Histone Deacetylase Inhibitors Trichostatin A and SK-7041 / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: This preclinical study is to determine whether the capacity of histone deacetylase (HDAC) inhibitors to enhance radiation response depends on temporal sequences of HDAC inhibition and irradiation. MATERIALS AND METHODS: The effects of HDAC inhibitors trichostatin A (TSA) and SK-7041 on radiosensitivity in human lung cancer cells were examined using a clonogenic assay, exposing cells to HDAC inhibitors in various sequences of HDAC inhibition and radiation. We performed Western blot of acetylated histone H3 and flow cytometry to analyze cell cycle phase distribution. RESULTS: TSA and SK-7041 augmented radiation cell lethality in an exposure time-dependent manner when delivered before irradiation. The impact of TSA and SK-7041 on radiosensitivity rapidly diminished when HDAC inhibition was delayed after irradiation. Radiation induced the acetylation of histone H3 in cells exposed to TSA, while irradiation alone had no effect on the expression of acetylated histone H3 in TSA-naive cells. Preirradiation exposure to TSA abrogated radiation-induced G2/M-phase arrest. When delivered after irradiation, TSA had no effect on the peak of radiation-induced G2/M-phase arrest. CONCLUSION: TSA and SK-7041 enhances radiosensitivity only when delivered before irradiation. Unless proven otherwise, it seems prudent to apply scheduling including preirradiation HDAC inhibition so that maximal radiosensitization is obtained.