Photochemical Fingerprinting Is a Sensitive Probe for the Detection of Synthetic Cannabinoid Receptor Agonists; toward Robust Point-of-Care Detection.

With synthetic cannabinoid receptor agonist (SCRA) use still prevalent across Europe and structurally advanced generations emerging, it is imperative that drug detection methods advance in parallel. SCRAs are a chemically diverse and evolving group, which makes rapid detection challenging. We have previously shown that fluorescence spectral fingerprinting (FSF) has the potential to provide rapid assessment of SCRA presence directly from street material with minimal processing and in saliva. Enhancing the sensitivity and discriminatory ability of this approach has high potential to accelerate the delivery of a point-of-care technology that can be used confidently by a range of stakeholders, from medical to prison staff. We demonstrate that a range of structurally distinct SCRAs are photochemically active and give rise to distinct FSFs after irradiation. To explore this in detail, we have synthesized a model series of compounds which mimic specific structural features of AM-694. Our data show that FSFs are sensitive to chemically conservative changes, with evidence that this relates to shifts in the electronic structure and cross-conjugation. Crucially, we find that the photochemical degradation rate is sensitive to individual structures and gives rise to a specific major product, the mechanism and identification of which we elucidate through density-functional theory (DFT) and time-dependent DFT. We test the potential of our hybrid "photochemical fingerprinting" approach to discriminate SCRAs by demonstrating SCRA detection from a simulated smoking apparatus in saliva. Our study shows the potential of tracking photochemical reactivity via FSFs for enhanced discrimination of SCRAs, with successful integration into a portable device.

Hitting the Jackpot - development of gas chromatography-mass spectrometry (GC-MS) and other rapid screening methods for the analysis of 18 fentanyl-derived synthetic opioids.

In recent years, the occurrence of synthetic opioid fentanyl and its derivatives has grown significantly in forensic casework. This study presents the synthesis and analysis of 18 fentalogs, selected based on information received from local law enforcement. This study provides colorimetric tests, thin-layer chromatography (TLC) which can potentially be utilized for presumptive screening of the target compounds, as bulk powders or as trace-level adulterants. The fully validated confirmatory GC-MS method (employing SIM mode) allows the identification of the 18 derivatives, five commonly encountered controlled substances and four adulterants, within 20 minutes. The cross-validated method described herein provides a sensitive screening and quantitation method for the illicit (and potentially harmful) components at trace levels (LOD = 0.007-0.822 µg/mL and LOQ = 0.023-2.742 µg/mL respectively). Spectral data [1 H-NMR, 13 C-NMR, 19 F-NMR, FT-IR, and HRMS] and assignments for the synthesized reference materials are also provided in the Supplementary Information for laboratories engaged in the routine analysis of fentanyl and its derivatives.

Inhibitory Kappa B Kinase α (IKKα) Inhibitors That Recapitulate Their Selectivity in Cells against Isoform-Related Biomarkers.

IKKß plays a central role in the canonical NF-kB pathway, which has been extensively characterized. The role of IKKα in the noncanonical NF-kB pathway, and indeed in the canonical pathway as a complex with IKKß, is less well understood. One major reason for this is the absence of chemical tools designed as selective inhibitors for IKKα over IKKß. Herein, we report for the first time a series of novel, potent, and selective inhibitors of IKKα. We demonstrate effective target engagement and selectivity with IKKα in U2OS cells through inhibition of IKKα-driven p100 phosphorylation in the noncanonical NF-kB pathway without affecting IKKß-dependent IKappa-Bα loss in the canonical pathway. These compounds represent the first chemical tools that can be used to further characterize the role of IKKα in cellular signaling, to dissect this from IKKß and to validate it in its own right as a target in inflammatory diseases.

Guilty by dissociation-development of gas chromatography-mass spectrometry (GC-MS) and other rapid screening methods for the analysis of 13 diphenidine-derived new psychoactive substances (NPSs).

The prevalence of new psychoactive substances (NPSs) in forensic casework has increased prominently in recent years. This has given rise to significant legal and analytical challenges in the identification of these substances. The requirement for validated, robust and rapid testing methodologies for these compounds is obvious. This study details the analysis of 13 synthesised diphenidine derivatives encountered in casework using presumptive testing, thin layer chromatography and gas chromatography-mass spectrometry (GC-MS). Specifically, the validated GC-MS method provides, for the first time, both a general screening method and quantification of the active components for seized solid samples, both in their pure form and in the presence of common adulterants. Graphical Abstract Chemical synthesis and forensic analysis of 13 diphenidine-derived new psychoactive substance(s).

Amide coupling reaction for the synthesis of bispyridine-based ligands and their complexation to platinum as dinuclear anticancer agents.

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. Isonicotinic acid, or its derivatives, are coupled to variable length diaminoalkane chains under an inert atmosphere in anhydrous DMF or DMSO with the use of a weak base, triethylamine, and a coupling agent, 1-propylphosphonic anhydride. The products precipitate from solution upon formation or can be precipitated by the addition of water. If desired, the ligands can be further purified by recrystallization from hot water. Dinuclear platinum complex synthesis using the bispyridine ligands is done in hot water using transplatin. The most informative of the chemical characterization techniques to determine the structure and gross purity of both the bispyridine ligands and the final platinum complexes is (1)H NMR with particular analysis of the aromatic region of the spectra (7-9 ppm). The platinum complexes have potential application as anticancer agents and the synthesis method can be modified to produce trinuclear and other multinuclear complexes with different hydrogen bonding functionality in the bridging ligand.

Development of gas chromatography-mass spectrometry (GC-MS) and other rapid screening methods for the analysis of 16 'legal high' cathinone derivatives.

The prevalence of so-called 'legal high' drugs in forensic science drug casework has increased markedly in recent years. This has given rise to both legal and analytical challenges in the identification of these substances. The requirement for validated, reliable and rapid testing methodologies for these compounds is obvious. This work reports the analysis of sixteen synthesised cathinone derivatives encountered in casework using presumptive testing, thin layer chromatography and gas chromatography-mass spectrometry (GC-MS).

Combining aspects of the platinum anticancer drugs picoplatin and BBR3464 to synthesize a new family of sterically hindered dinuclear complexes; their synthesis, binding kinetics and cytotoxicity.

Picoplatin is a sterically hindered mononuclear platinum drug undergoing clinical trials. The 2-methylpyridine ring provides steric hindrance to the drug, preventing attack from biological nucleophiles. BBR3464 is a trinuclear platinum drug which was recently in Phase II clinical trials, and is highly cytotoxic both in vitro and in vivo; it derives this activity through the flexible adducts it forms with DNA. In this work we sought to combine the properties of both drugs to synthesise a family of sterically hindered, dinuclear platinum complexes as potential anticancer agents. The bis-pyridyl-based ligands were synthesised through a peptide coupling reaction using diaminoalkanes of differing lengths (n = 2, 4 or 8) and 4-carboxypyridine or 2-methyl-4-carboxypyridine. The resultant dinuclear platinum complexes were synthesised by reacting two equivalents of transplatin or mono-aquated transplatin to each ligand, followed by purification by precipitation with acetone. The unprotected complexes react faster with 5'-guanosine monophosphate (drug to nucleotide ratio 1:2; t(1/2) = 2 h), glutathione (1:10, t(1/2) = 55 min) and human serum albumin (HSA) (1:1, t(1/2) = 24 h) compared to their hindered, protected equivalents (5'-guanosine monophosphate, t(1/2) = 3.5 h; glutathione = 1.7 h; HSA, t(1/2) = 110 h). The complexes were tested for in vitro cytotoxicity in the A2780 and A2780/cp70 ovarian cancer cell line. The unprotected platinum complexes were more cytotoxic than their protected derivatives, but none of the complexes were able to overcome resistance. The results provide important proof-of-concept for the development of a larger family of sterically hindered multinuclear-based platinum complexes.

Doing the methylene shuffle--further insights into the inhibition of mitotic kinesin Eg5 with S-trityl L-cysteine.

S-Trityl L-cysteine (STLC) is an inhibitor of the mitotic kinesin Eg5 with potential as an antimitotic chemotherapeutic agent. We previously reported the crystal structure of the ligand-protein complex, and now for the first time, have quantified the interactions using a molecular dynamics based approach. Based on these data, we have explored the SAR of the trityl head group using the methylene shuffle strategy to expand the occupation of one of the hydrophobic pockets. The most potent compounds exhibit strong (<100 nM) inhibition of Eg5 in the basal ATPase assay and inhibit growth in a variety of tumour-derived cell lines.

Triphenylbutanamines: kinesin spindle protein inhibitors with in vivo antitumor activity.

The human mitotic kinesin Eg5 represents a novel mitotic spindle target for cancer chemotherapy. We previously identified S-trityl-l-cysteine (STLC) and related analogues as selective potent inhibitors of Eg5. We herein report on the development of a series of 4,4,4-triphenylbutan-1-amine inhibitors derived from the STLC scaffold. This new generation systematically improves on potency: the most potent C-trityl analogues exhibit K(i)(app) ≤ 10 nM and GI(50) ≈ 50 nM, comparable to results from the phase II clinical benchmark ispinesib. Crystallographic studies reveal that they adopt the same overall binding configuration as S-trityl analogues at an allosteric site formed by loop L5 of Eg5. Evaluation of their druglike properties reveals favorable profiles for future development and, in the clinical candidate ispinesib, moderate hERG and CYP inhibition. One triphenylbutanamine analogue and ispinesib possess very good bioavailability (51% and 45%, respectively), with the former showing in vivo antitumor growth activity in nude mice xenograft studies.

Structure-activity relationship for the first-in-class clinical steroid sulfatase inhibitor Irosustat (STX64, BN83495).

Structure-activity relationship studies were conducted on Irosustat (STX64, BN83495), the first steroid sulfatase (STS) inhibitor to enter diverse clinical trials for patients with advanced hormone-dependent cancer. The size of its aliphatic ring was expanded; its sulfamate group was N,N-dimethylated, relocated to another position and flanked by an adjacent methoxy group; and series of quinolin-2(1H)-one and quinoline derivatives of Irosustat were explored. The STS inhibitory activities of the synthesised compounds were assessed in a preparation of JEG-3 cells. Stepwise enlargement of the aliphatic ring from 7 to 11 members increases potency, although a further increase in ring size is detrimental. The best STS inhibitors in vitro had IC50 values between 0.015 and 0.025 nM. Other modifications made to Irosustat were found to either abolish or significantly weaken its activity. An azomethine adduct of Irosustat with N,N-dimethylformamide (DMF) was isolated, and crystal structures of Irosustat and this adduct were determined. Docking studies were conducted to explore the potential interactions between compounds and the active site of STS, and suggest a sulfamoyl group transfer to formylglycine 75 during the inactivation mechanism.

Evaluation of anionic half generation 3.5-6.5 poly(amidoamine) dendrimers as delivery vehicles for the active component of the anticancer drug cisplatin.

Aquated cisplatin was added to half-generation PAMAM dendrimers and the resultant complexes were purified by centrifuge. The drug-dendrimer complexes were then characterised by 1-D and diffusion (1)H NMR and ICP-AES. The amount of drug bound was found to increase in proportion with dendrimer size: G3.5, 22 cis-{Pt(NH(3))(2)} molecules per dendrimer; G4.5, 37; G5.5, 54; and G6.5, 94, which represent only a fraction of the available binding sites on each dendrimer (68, 58, 42 and 37%, respectively). Drug release studies showed that some drug remains bound to the dendrimer even after prolonged incubation with 5'-GMP at temperatures of 60°C for over a week (percentage of drug released 18, 30, 35 and 63%, respectively). Attachment of the drug was found to decrease the radius of the dendrimers. Finally, the effect of the dendrimer on drug cytotoxicity was determined using in vitro assays with the A2780, A2780cis and A2780cp ovarian cancer cell lines. The free dendrimers display no cytotoxicity whilst the drug-dendrimer complexes showed moderate activity. In vivo activity was examined using an A2780 tumour xenograft. Cisplatin, at its maximum tolerated dose of 6 mg/kg, reduced tumour size by 33% compared to an untreated control group. The G6.5 cisplatin-dendrimer complex was administered at two doses (6 and 8 mg/kg equivalent of cisplatin). Both were well tolerated by the mice. The lower dose displayed comparable activity to cisplatin with a tumour volume reduction of 32%, but the higher dose was significantly more active than free cisplatin with a tumour reduction of 45%.

A new therapeutic strategy against hormone-dependent breast cancer: the preclinical development of a dual aromatase and sulfatase inhibitor.

PURPOSE: The production of E2 is paramount for the growth of estrogen receptor-positive breast cancer. Various strategies have been used, including the use of enzyme inhibitors against either aromatase (AROM) or steroid sulfatase (STS), in an attempt to ablate E2 levels. Both these enzymes play a critical role in the formation of estrogenic steroids and their inhibitors are now showing success in the clinic. EXPERIMENTAL DESIGN: We show here, in a xenograft nude mouse model, that the inhibition of both enzymes using STX681, a dual AROM and STS inhibitor (DASI), is a potential new therapeutic strategy against HDBC. MCF-7 cells stably expressing either AROM cDNA (MCF-7(AROM)) or STS cDNA (MCF-7(STS)) were generated. Ovariectomized MF-1 female nude mice receiving s.c. injections of either androstenedione (A(4)) or E2 sulfate and bearing either MCF-7(AROM) or MCF-7(STS) tumors were orally treated with STX64, letrozole, or STX681. Treatment was administered for 28 days. Mice were weighed and tumor measurements were taken weekly. RESULTS: STX64, a potent STS inhibitor, completely blocked MCF-7(STS) tumor growth but failed to attenuate MCF-7(AROM) tumor growth. In contrast, letrozole inhibited MCF-7(AROM) tumors but had no effect on MCF-7(STS) tumors. STX681 completely inhibited the growth of both tumors. AROM and STS activity was also completely inhibited by STX681, which was accompanied by a significant reduction in plasma E2 levels. CONCLUSIONS: This study indicates that targeting both the AROM and the STS enzyme with a DASI inhibits HDBC growth and is therefore a potentially novel treatment for this malignancy.

Synthesis of aromatase inhibitors and dual aromatase steroid sulfatase inhibitors by linking an arylsulfamate motif to 4-(4H-1,2,4-triazol-4-ylamino)benzonitrile: SAR, crystal structures, in vitro and in vivo activities.

4-(((4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino)methyl)phenyl sulfamate (6 a) was the first dual aromatase-sulfatase inhibitor (DASI) reported. Several series of its derivatives with various linker systems between the steroid sulfatase (STS) and the aromatase inhibitory pharmacophores were synthesised and evaluated in JEG-3 cells. The X-ray crystal structures of the aromatase inhibitors, DASI precursors 42 d and 60, and DASI 43 h were determined. Nearly all derivatives show improved in vitro aromatase inhibition over 6 a but decreased STS inhibition. The best aromatase inhibitor is 42 e (IC(50)=0.26 nM) and the best DASI is 43 e (IC(50 aromatase)=0.45 nM, IC(50 STS)=1200 nM). SAR for aromatase inhibition shows that compounds containing an alkylene- and thioether-based linker system are more potent than those that are ether-, sulfone-, or sulfonamide-based, and that the length of the linker has a limited effect on aromatase inhibition beyond two methylene units. Compounds 43 d-f were studied in vivo (10 mg kg(-1), single, p.o.). The most potent DASI is 43 e, which inhibited PMSG-induced plasma estradiol levels by 92 % and liver STS activity by 98 % 3 h after dosing. These results further strengthen the concept of designing and developing DASIs for potential treatment of hormone-related cancers.

Dual aromatase-steroid sulfatase inhibitors.

By introducting the steroid sulfatase inhibitory pharmacophore into aromatase inhibitor 1 (YM511), two series of single agent dual aromatase-sulfatase inhibitors (DASIs) were generated. The best DASIs in vitro (JEG-3 cells) are 5, (IC50(aromatase) = 0.82 nM; IC50(sulfatase) = 39 nM), and 14, (IC50(aromatase) = 0.77 nM; IC50(sulfatase) = 590 nM). X-ray crystallography of 5, and docking studies of selected compounds into an aromatase homology model and the steroid sulfatase crystal structure are presented. Both 5 and 14 inhibit aromatase and sulfatase in PMSG pretreated adult female Wistar rats potently 3 h after a single oral 10 mg/kg dose. Almost complete dual inhibition is observed for 5 but the levels were reduced to 85% (aromatase) and 72% (sulfatase) after 24 h. DASI 5 did not inhibit aldosterone synthesis. The development of a potent and selective DASI should allow the therapeutic potential of dual aromatase-sulfatase inhibition in hormone-dependent breast cancer to be assessed.

First crystal structures of human carbonic anhydrase II in complex with dual aromatase-steroid sulfatase inhibitors.

Carbonic anhydrase (CA) catalyzes the reversible hydration of carbon dioxide to hydrogen carbonate. The role of CA in maintaining pH balance has made it an attractive drug target for the treatment of cancer, and it has recently been implicated in the delivery of sulfamate-containing drugs. With the acceptance of steroid sulfatase as a target for hormone-dependent cancer, novel dual aromatase-steroid sulfatase inhibitors (DASIs) containing a sulfamate group are now being developed. In this study, we show that CA II is potently inhibited by several members of this class of inhibitor. The structures of CA II complexed with 4-[(4-O-sulfamoylbenzyl)(4-cyanophenyl)amino]-4H-[1,2,4]triazole (K(D) = 84 +/- 5 nM) and 4-[(3-bromo-4-O-sulfamoylbenzyl)(4-cyanophenyl)amino]-4H-[1,2,4]triazole (K(D) = 454 +/- 29 nM) are reported to 2.02 and 1.76 A, respectively. Both inhibitors ligate to the active site zinc(II) atom via their sulfamate nitrogen, while the rest of the molecule is contained within the hydrophobic binding pocket. Key protein residues include Val-121, Phe-131, Val-135, Val-143, Leu-141, Leu-198, Pro-202, and Leu-204. Despite being structurally similar, the two ligands experience different types of binding particularly in the sulfamate-containing aromatic ring and the opposite geometric arrangement of the triazole and cyanophenyl groups around the configurationally invertible central nitrogen atom. Small changes in inhibitor structure can cause large changes in binding to CA II, and this underlines the importance of structure-based drug design with this enzyme and other isoforms relevant to potential anticancer therapy. Moreover, these results underpin the idea that binding to erythrocyte CA II may be a general method of stabilizing and delivering sulfamate-based drugs in vivo.

First dual aromatase-steroid sulfatase inhibitors.

Aromatase inhibitors in clinical use block the biosynthesis of estrogens. Hydrolysis of estrone 3-sulfate by steroid sulfatase is an important additional source of tumor estrogen, and blockade of both enzymes should provide a more effective endocrine therapy. Sulfamoylated derivatives of the aromatase inhibitor YM511 inhibited sulfatase and aromatase in JEG-3 cells with respective IC(50) values of 20-227 and 0.82-100 nM (cf. letrozole, 0.89 nM). One dual inhibitor was potent against both enzymes in vivo, validating the concept.