A high throughput dried DMSO LogD lipophilicity measurement based on 96-well shake-flask and atmospheric pressure photoionization mass spectrometry detection

4-Substituted-2-Thiazole Amides as Viral Replication Inhibitors of Alphaviruses

2-(Methylthio)-N-(4-(naphthalen-2-yl)thiazol-2-yl)nicotinamide 1 was identified as an inhibitor against Chikungunya virus (CHIKV) with good antiviral activity [EC50 = 0.6 μM; EC90 = 0.93 μM and viral titer reduction (VTR) of 6.9 logs at 10 μM concentration] with no observed cytotoxicity (CC50 = 132 μM) in normal human dermal fibroblast (NHDF) cells. Structure-activity relationship (SAR) studies to further improve the potency, efficacy, and drug-like properties of 1 led to the discovery of a new potent inhibitor N-(4-(3-((4-cyanophenyl)amino)phenyl)thiazol-2-yl)-2-(methylthio)nicotinamide 26, which showed a VTR of 8.7 logs at 10 μM against CHIKV and an EC90 of 0.45 μM with considerably improved MLM stability (t1/2 = 74 min) as compared to 1. Mechanism of action studies show that 26 inhibits alphavirus replication by blocking subgenomic viral RNA translation and structural protein synthesis. The in vivo efficacy studies of compound 26 on CHIKV infection in mice are reported.

High-throughput screening of LogD by using a sample pooling approach based on the traditional shake flask method

A new approach for screening LogD is presented. The method is based on the shake flask method combined with rapid generic LC-MS/MS bioanalysis by using a sample pooling approach that enables high-throughput screening of LogD or LogP in the drug discovery stage. The method is evaluated by a comparison of measured LogD between single and pooled compounds for a test set of structurally diverse compounds with a wide range of LogD values (from -0.04 to 6.01). Test compounds include 10 commercially available drug standards along with 27 new chemical entities. A good correlation (RMSE = 0.21, R2 = 0.9879) of LogD between the single and pooled compounds was obtained, suggesting that at least 37 compounds can be simultaneously measured with acceptable accuracy. The sample pooling method significantly reduced the number of bioanalysis samples as compared to the single compound measurement by the conventional shake flask method. The impact of DMSO content on LogD measurement was also investigated and the result demonstrated that at least 0.5% DMSO was tolerated in this method. The current new development will facilitate the drug discovery process by more rapidly assessing the LogD or LogP of drug candidates.

Identification of natural cytochalasins as leads for neglected tropical diseases drug discovery

Investigating the chemical diversity of natural products from tropical environments is an inspiring approach to developing new drug candidates for neglected tropical diseases (NTDs). In the present study, phenotypic screenings for antiprotozoal activity and a combination of computational and biological approaches enabled the identification and characterization of four cytochalasins, which are fungal metabolites from Brazilian biodiversity sources. Cytochalasins A-D exhibited IC50 values ranging from 2 to 20 μM against intracellular Trypanosoma cruzi and Leishmania infantum amastigotes, values comparable to those of the standard drugs benznidazole and miltefosine for Chagas disease and leishmaniasis, respectively. Furthermore, cytochalasins A-D reduced L. infantum infections by more than 80% in THP-1 cells, most likely due to the inhibition of phagocytosis by interactions with actin. Molecular modelling studies have provided useful insights into the mechanism of action of this class of compounds. Furthermore, cytochalasins A-D showed moderate cytotoxicity against normal cell lines (HFF-1, THP-1, and HepG2) and a good overall profile for oral bioavailability assessed in vitro. The results of this study support the use of natural products from Brazilian biodiversity sources to find potential drug candidates for two of the most important NTDs.

Multiparameter Optimization of Trypanocidal Cruzain Inhibitors With In Vivo Activity and Favorable Pharmacokinetics

Cruzain, the main cysteine protease of Trypanosoma cruzi, plays key roles in all stages of the parasite's life cycle, including nutrition acquisition, differentiation, evasion of the host immune system, and invasion of host cells. Thus, inhibition of this validated target may lead to the development of novel drugs for the treatment of Chagas disease. In this study, a multiparameter optimization (MPO) approach, molecular modeling, and structure-activity relationships (SARs) were employed for the identification of new benzimidazole derivatives as potent competitive inhibitors of cruzain with trypanocidal activity and suitable pharmacokinetics. Extensive pharmacokinetic studies enabled the identification of metabolically stable and permeable compounds with high selectivity indices. CYP3A4 was found to be involved in the main metabolic pathway, and the identification of metabolic soft spots provided insights into molecular optimization. Compound 28, which showed a promising trade-off between pharmacodynamics and pharmacokinetics, caused no acute toxicity and reduced parasite burden both in vitro and in vivo.

Targeting Chikungunya Virus Replication by Benzoannulene Inhibitors

A benzo[6]annulene, 4-(tert-butyl)-N-(3-methoxy-5,6,7,8-tetrahydronaphthalen-2-yl) benzamide (1a), was identified as an inhibitor against Chikungunya virus (CHIKV) with antiviral activity EC₉₀ = 1.45 μM and viral titer reduction (VTR) of 2.5 log at 10 μM with no observed cytotoxicity (CC₅₀ = 169 μM) in normal human dermal fibroblast cells. Chemistry efforts to improve potency, efficacy, and drug-like properties of 1a resulted in a novel lead compound 8q, which possessed excellent cellular antiviral activity (EC₉₀ = 270 nM and VTR of 4.5 log at 10 μM) and improved liver microsomal stability. CHIKV resistance to an analog of 1a, compound 1c, tracked to a mutation in the nsP3 macrodomain. Further mechanism of action studies showed compounds working through inhibition of human dihydroorotate dehydrogenase in addition to CHIKV nsP3 macrodomain. Moderate efficacy was observed in an in vivo CHIKV challenge mouse model for compound 8q as viral replication was rescued from the pyrimidine salvage pathway.

Artificial intelligence in the early stages of drug discovery

Although the use of computational methods within the pharmaceutical industry is well established, there is an urgent need for new approaches that can improve and optimize the pipeline of drug discovery and development. In spite of the fact that there is no unique solution for this need for innovation, there has recently been a strong interest in the use of Artificial Intelligence for this purpose. As a matter of fact, not only there have been major contributions from the scientific community in this respect, but there has also been a growing partnership between the pharmaceutical industry and Artificial Intelligence companies. Beyond these contributions and efforts there is an underlying question, which we intend to discuss in this review: can the intrinsic difficulties within the drug discovery process be overcome with the implementation of Artificial Intelligence? While this is an open question, in this work we will focus on the advantages that these algorithms provide over the traditional methods in the context of early drug discovery.

Optimizing Pharmacokinetic Property Prediction Based on Integrated Datasets and a Deep Learning Approach

Oral bioavailability (OBA)-related pharmacokinetic properties, such as aqueous solubility, lipophilicity, and intestinal membrane permeability, play a significant role in drug discovery. However, their measurement is usually costly and time-consuming. Therefore, prediction models based on diverse approaches have been established in recent decades. Computational prediction of molecular properties has become an important step in drug discovery, aiming to identify potential drug-like candidates and reduce costs. However, limitations related to dataset capacity and algorithm adaptation still place restrictions on the applicability of the related models. In this study, we considered both dataset and algorithm optimization to address the challenge of predicting OBA-related molecular properties. Benchmark datasets of aqueous solubility (log S), lipophilicity (log D), and membrane permeability measured using the Caco-2 cell line (log P_app) were constructed by merging and calibrating experimental data from diverse articles and databases. Then, a novel molecular property prediction model, called a multiembedding-based synthetic network (MESN), was generated by applying a deep learning algorithm based on the synthesis of multiple types of molecular embeddings. MESN achieves performance improvements over other state-of-the-art methods for the prediction of aqueous solubility, lipophilicity, and membrane permeability. Results were also obtained using several other algorithms and independent validation datasets as a control study. Moreover, a dimension reduction analysis (based on t-distributed stochastic neighbor embedding, t-SNE) and an atomic feature similarity analysis showed that the molecular embeddings extracted from the MESN model exhibit good clustering and diversity. Overall, considering the fundamental role of the data and the superior prediction performance of the model, we highlight the applicability of MESN on benchmark datasets for further utility in drug discovery-related molecular property prediction.

Miniaturized shake-flask HPLC method for determination of distribution coefficient of drugs used in inflammatory bowel diseases

A new method for determination of distribution coefficient of drugs azathioprine, 6-mercaptopurine and 6-thioguanine and nutrient folic acid used in the treatment of inflammatory bowel disease based on a miniaturized shake-flask and HPLC/DAD was developed. Special attention was made to the most commonly reported problems in the measurement of distribution coefficients using a shake-flask method such as mixing technique, speed and time, the temperature of experiment, type of buffer and its pH as well as n-octanol/buffer phase ratio. The concentration of compounds in the buffer is determined by HPLC directly from shake flasks or conventional 2-mL vials. The developed method was fully validated according to ICH guidelines. Furthermore, experimental data were successfully compared with lipophilicity and human intestinal absorption calculated by the use of four different theoretical approaches. The method shows potential for high-throughput measurements of a large number of compounds.

Lowering Lipophilicity by Adding Carbon: AzaSpiroHeptanes, a logD Lowering Twist

We have conducted an analysis of azaspiro[3.3]heptanes used as replacements for morpholines, piperidines, and piperazines in a medicinal chemistry context. In most cases, introducing a spirocyclic center lowered the measured logD _7.4 of the corresponding molecules by as much as -1.0 relative to the more usual heterocycle. This may seem counterintuitive, as the net change in the molecule is the addition of a single carbon atom, but it may be rationalized in terms of increased basicity. An exception to this was found with N-linked 2-azaspiro[3.3]heptane, where logD _7.4 increased by as much as +0.5, consistent with the addition of carbon. During our investigation, we also concluded that azaspiro[3.3]heptanes are most likely not suitable bioisosteres for morpholines, piperidines, and piperazines, when not used as terminal groups, due to significant changes in their geometry.

PSMA-Oriented Target Delivery of Novel Anticancer Prodrugs: Design, Synthesis, and Biological Evaluations of Oligopeptide-Camptothecin Conjugates

Clinical applications of camptothecin (CPT) have been heavily hindered due to its non-targeted toxicity, active lactone ring instability, and poor water solubility. Targeted drug delivery systems may offer the possibility to overcome the above issues as reported. In this research, a series of prostate-specific membrane antigen (PSMA)-activated CPT prodrugs were designed and synthesized by coupling water-soluble pentapeptide, a PSMA hydrolyzing substrate, to CPT through an appropriate linker. The cytotoxicity of CPT prodrugs was masked temporarily until they were hydrolyzed by the PSMA present within the tumor sites, which restored cytotoxicity. The in vitro selective cytotoxic activities of the prodrugs were evaluated against PSMA-expressing human prostate cancer cells LNCaP-FGC and non-PSMA-expressing cancer cells HepG2, Hela, MCF-7, DU145, PC-3 and normal cells MDCK, LO2 by standard methylthiazol tetrazolium (MTT) assay. Most of the newly synthesized CPT prodrugs showed excellent selective toxicity to PSMA-producing prostate cancer cells LNCaP-FGC with improved water solubility. From among the library, CPT-HT-J-ZL₁₂ showed the best cytotoxic selectivity between the PSMA-expressing and the non-PSMA-expressing cancer cells. For example, the cytotoxicity of CPT-HT-J-ZL₁₂ (IC₅₀ = 1.00 ± 0.20 µM) against LNCaP-FGC (PSMA⁺) was 40-fold, 40-fold, 21-fold, 5-fold and 40-fold, respectively, higher than that against the non-PSMA-expressing cells HepG2 (IC₅₀ > 40.00 µM), Hela (IC₅₀ > 40.00 µM), MCF-7 (IC₅₀ = 21.68 ± 4.96 µM), DU145 (IC₅₀ = 5.40 ± 1.22 µM), PC-3 (IC₅₀ = 42.96 ± 3.69 µM) cells. Moreover, CPT-HT-J-ZL₁₂ exhibited low cytotoxicity (IC₅₀ > 40 μM) towards MDCK and LO2 cells. The cellular uptake experiment demonstrated the superior PSMA-targeting ability of the CPT-HT-J-ZL₁₂, which was significantly accumulated in LNCaP-FGC (PSMA⁺), while it was minimized in HepG2 (PSMA⁻) cells. Further cell apoptosis analyses indicated that it showed a dramatically higher apoptosis-inducing activity in LNCaP-FGC (PSMA⁺) cells than in HepG2 (PSMA⁻) cells. Cell cycle analysis indicated that CPT-HT-J-ZL₁₂ could induce cell cycle arrest at the S phase.

A confidence predictor for logD using conformal regression and a support-vector machine

Lipophilicity is a major determinant of ADMET properties and overall suitability of drug candidates. We have developed large-scale models to predict water–octanol distribution coefficient (logD) for chemical compounds, aiding drug discovery projects. Using ACD/logD data for 1.6 million compounds from the ChEMBL database, models are created and evaluated by a support-vector machine with a linear kernel using conformal prediction methodology, outputting prediction intervals at a specified confidence level. The resulting model shows a predictive ability of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {Q}^{2}=0.973$$\end{document}Q2=0.973 and with the best performing nonconformity measure having median prediction interval of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\pm ~0.39$$\end{document}±0.39 log units at 80% confidence and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\pm ~0.60$$\end{document}±0.60 log units at 90% confidence. The model is available as an online service via an OpenAPI interface, a web page with a molecular editor, and we also publish predictive values at 90% confidence level for 91 M PubChem structures in RDF format for download and as an URI resolver service.

Lipophilicity Studies on Thiosemicarbazide Derivatives

The lipophilicity of two series of thiosemicarbazide derivatives was assessed by the RP-HPLC method with the RP-18 chromatographic column and the methanol–water mixture as the mobile phase. Distribution coefficients logP_HPLC were compared to calculated values generated by commonly used AClogP software and quantum chemical calculations. The reliability of the predictions was evaluated using the correlation matrix and PCA. For 4-benzoylthiosemicarbazides, a high correlation between theoretical and experimental logP parameters was obtained using the XlogP3 algorithm, while for 4-aryl/(cyclohexyl)thiosemicarbazides, the XlogP2 parameter was strongly correlated with the experimentally obtained logP.

Intestinal Transport Characteristics and Metabolism of C-Glucosyl Dihydrochalcone, Aspalathin

Insight into the mechanisms of intestinal transport and metabolism of aspalathin will provide important information for dose optimisation, in particular for studies using mouse models. Aspalathin transportation across the intestinal barrier (Caco-2 monolayer) tested at 1–150 µM had an apparent rate of permeability (P_app) typical of poorly absorbed compounds (1.73 × 10⁻⁶ cm/s). Major glucose transporters, sodium glucose linked transporter 1 (SGLT1) and glucose transporter 2 (GLUT2), and efflux protein (P-glycoprotein, PgP) (1.84 × 10⁻⁶ cm/s; efflux ratio: 1.1) were excluded as primary transporters, since the P_app of aspalathin was not affected by the presence of specific inhibitors. The P_app of aspalathin was also not affected by constituents of aspalathin-enriched rooibos extracts, but was affected by high glucose concentration (20.5 mM), which decreased the P_app value to 2.9 × 10⁻⁷ cm/s. Aspalathin metabolites (sulphated, glucuronidated and methylated) were found in mouse urine, but not in blood, following an oral dose of 50 mg/kg body weight of the pure compound. Sulphates were the predominant metabolites. These findings suggest that aspalathin is absorbed and metabolised in mice to mostly sulphate conjugates detected in urine. Mechanistically, we showed that aspalathin is not actively transported by the glucose transporters, but presumably passes the monolayer paracellularly.

In vitro models to estimate drug penetration through the compromised stratum corneum barrier

OBJECTIVES

The phospholipid vesicle-based permeation assay (PVPA) is a recently established in vitro stratum corneum model to estimate the permeability of intact and healthy skin. The aim here was to further evolve this model to mimic the stratum corneum in a compromised skin barrier by reducing the barrier functions in a controlled manner.

METHODS

To mimic compromised skin barriers, PVPA barriers were prepared with explicitly defined reduced barrier function and compared with literature data from both human and animal skin with compromised barrier properties. Caffeine, diclofenac sodium, chloramphenicol and the hydrophilic marker calcein were tested to compare the PVPA models with established models.

RESULTS AND DISCUSSIONS

The established PVPA models mimicking the stratum corneum in healthy skin showed good correlation with biological barriers by ranking drugs similar to those ranked by the pig ear skin model and were comparable to literature data on permeation through healthy human skin. The PVPA models provided reproducible and consistent results with a distinction between the barriers mimicking compromised and healthy skin. The trends in increasing drug permeation with an increasing degree of compromised barriers for the model drugs were similar to the literature data from other in vivo and in vitro models.

CONCLUSIONS

The PVPA models have the potential to provide permeation predictions when investigating drugs or cosmeceuticals intended for various compromised skin conditions and can thus possibly reduce the time and cost of testing as well as the use of animal testing in the early development of drug candidates, drugs and cosmeceuticals.

A Series of New Ligustrazine-Triterpenes Derivatives as Anti-Tumor Agents: Design, Synthesis, and Biological Evaluation

A series of novel ligustrazine-triterpenes derivatives was designed, synthesized and screened for their cytotoxicity against five cancer cell lines (Bel-7402, HepG2, HT-29, Hela, and MCF-7) and Madin-Darby canine kidney (MDCK). Current study suggested that most of the ligustrazine-triterpenes conjunctions showed better cytotoxicity than the starting materials. In particular, compound 4a exhibited better cytotoxic activity (IC₅₀ < 5.23 μM) against Bel-7402, HT-29, MCF-7, Hela, and HepG2 than the standard anticancer drug cisplatin (DDP). The cytotoxicity selectivity detection revealed that 4a exhibited low cytotoxicity (IC₅₀ > 20 μM) towards MDCK cells. A combination of fluorescence staining observation and flow cytometric analysis indicated that 4a could induce HepG2 cell apoptosis. Further studies suggested that 4a-induced apoptosis is mediated through depolarization of the mitochondrial membrane potential and increase of intracellular free Ca²⁺ concentration. In addition, the structure-activity relationships of these derivatives were briefly discussed.

Interpreting physicochemical experimental data sets

With the wealth of experimental physicochemical data available to chemoinformaticians from the literature, commercial, and company databases an increasing challenge is the interpretation of such datasets. Subtle differences in experimental methodology used to generate these datasets can give rise to variations in physicochemical property values. Such methodology nuances will be apparent to an expert experimentalist but not necessarily to the data analyst and modeller. This paper describes the differences between common methodologies for measuring the four most important physicochemical properties namely aqueous solubility, octan-1-ol/water distribution coefficient, pK(a) and plasma protein binding highlighting key factors that can lead to systematic differences. Insight is given into how to identify datasets suitable for combining.

Efficacy and pharmacokinetic evaluation of a novel anti-malarial compound (NP046) in a mouse model

BACKGROUND

Even though malaria is a completely preventable and treatable disease, it remains a threat to human life and a burden to the global economy due to the emergence of multiple-drug resistant malaria parasites. According to the World Malaria Report 2013, in 2012 there were an estimated 207 million malaria cases and 627,000 deaths. Thus, the discovery and development of new, effective anti-malarial drugs are required. To achieve this goal, the Department of Chemistry at the University of the Free State has synthesized a number of novel amino-alkylated chalcones and analogues, which showed in vitro anti-malarial activity against both chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains. The lead compound (NP046) was selected for a comprehensive pharmacokinetic (PK) and in vivo efficacy evaluation in a mouse model.

METHODS

In vivo efficacy: Water solutions of NP046 were administered orally at 50 and 10 mg/kg using oral gavage and IV at 5 and 1 mg/kg via the dorsal penile vein to Plasmodium berghei (ANKA strain) infected male C57BL/6 mice (n = 5), once a day for four days. Blood samples were collected via tail bleeding in tubes containing phosphate buffer saline (PBS) on day five to determine the % parasitaemia by flow cytometry.In vivo PK: NP046 solutions in water were administered orally (50 and 10 mg/kg) and IV (5 mg/kg) to male C57BL/6 mice (n = 5). Blood samples were collected via tail bleeding into heparinized tubes and analysed using a validated LC-MS/MS assay. Data obtained from the concentration-time profile was evaluated using Summit PK software to determine the PK parameters of NP046.

RESULTS

NP046 inhibited parasite growth for the oral and IV groups. Better parasite growth inhibition was observed for the IV group. The PK evaluation of NP046 showed low oral bioavailability (3.2% and 6% at 50 mg/kg and 10 mg/kg dose, respectively and a moderate mean half-life ranging from 3.1 to 4.4 hours.

CONCLUSION

Even though the oral bioavailability of NP046 is low, its percentage parasite growth inhibition is promising, but in order to improve the oral bioavailability, structure-activity-relationship (SAR) optimization studies are currently being conducted.

Carrier Mediated Distribution System (CAMDIS): a new approach for the measurement of octanol/water distribution coefficients

Here we present a miniaturized assay, referred to as Carrier-Mediated Distribution System (CAMDIS) for fast and reliable measurement of octanol/water distribution coefficients, log D(oct). By introducing a filter support for octanol, phase separation from water is facilitated and the tendency of emulsion formation (emulsification) at the interface is reduced. A guideline for the best practice of CAMDIS is given, describing a strategy to manage drug adsorption at the filter-supported octanol/buffer interface. We validated the assay on a set of 52 structurally diverse drugs with known shake flask log D(oct) values. Excellent agreement with literature data (r(2) = 0.996, standard error of estimate, SEE = 0.111), high reproducibility (standard deviation, SD < 0.1 log D(oct) units), minimal sample consumption (10 μL of 100 μM DMSO stock solution) and a broad analytical range (log D(oct) range = -0.5 to 4.2) make CAMDIS a valuable tool for the high-throughput assessment of log D(oc)t.

Identification of novel substrates and structure-activity relationship of cellular uptake mediated by human organic cation transporters 1 and 2

Recently the clinical importance of human organic cation transporters 1 (hOCT1/SLC22A1) and 2 (hOCT2/SLC22A2) in drug disposition, for example, clearance, toxicity, and drug-drug interactions, have been highlighted [Annu. Rev. Pharmacol. Toxicol. 2012, 52, 249-273; Nat. Rev. Drug Discovery 2010, 9 (3), 215-236]. Consequently, there is an extensive need for experimental assessment of structure-transport relationships as well as tools to predict drug uptake by these transporters in ADMET (absorption, distribution, metabolism, excretion, toxicity) investigations. In the present study, we developed a robust assay for screening unlabeled compound uptake by hOCT1 and hOCT2 using transfected HEK293 cells. For the first time, an extensive data set comprising uptake of 354 compounds is presented. As expected, there was a large overlap in substrate specificity between the two organic cation transporters. However, several compounds selectively taken up by either hOCT1 or hOCT2 were identified. In particular, a chemical series of phenylthiophenecarboxamide ureas was identified as selective hOCT1 substrates. Moreover, the drivers for transport differed: molecular volume was the most important determinant of hOCT1 substrates, whereas H-bonding parameters like polar surface area (PSA) dominated for hOCT2.

Quantifying the CDK inhibitor VMY-1-103's activity and tissue levels in an in vivo tumor model by LC-MS/MS and by MRI

The development of new small molecule-based therapeutic drugs requires accurate quantification of drug bioavailability, biological activity and treatment efficacy. Rapidly measuring these endpoints is often hampered by the lack of efficient assay platforms with high sensitivity and specificity. Using an in vivo model system, we report a simple and sensitive liquid chromatography-tandem mass spectrometry assay to quantify the bioavailability of a recently developed novel cyclin-dependent kinase inhibitor VMY-1-103, a purvalanol B-based analog whose biological activity is enhanced via dansylation. We developed a rapid organic phase extraction technique and validated wide and functional VMY-1-103 distribution in various mouse tissues, consistent with its enhanced potency previously observed in a variety of human cancer cell lines. More importantly, in vivo MRI and single voxel proton MR-Spectroscopy further established that VMY-1-103 inhibited disease progression and affected key metabolites in a mouse model of hedgehog-driven medulloblastoma.