Lessons learnt in photocatalysis - the influence of solvent polarity and the photostability of the photocatalyst

Herein, we show that there is significant variation in both the triplet energies and redox properties of photocatalysts as a function of solvent based on a study of eight PCs in four solvents of varying polarity. A range of photocatalytic electron and energy transfer reactions were investigated using a subset of the PCs. For the photoredox reactions, the yields are not correlated with solvent polarity. Instead, when the PC could promote the formation of the target product, we observed photodegradation for all PCs across all solvents, something that is rarely investigated in the literature. This, therefore, makes it difficult to ascertain whether the parent PC and/or the photodegraded product is responsible for the photochemistry, or indeed, whether photodegradation is actually detrimental to the reaction yield. Conversely, the PCs were found to be photostable for energy transfer reactions; however, yields were not correlated to the triplet energies of the PCs, highlighting that triplet energies alone are not a suitable descriptor to discriminate the performance between PCs in photoinduced energy transfer processes.

Structural Control of Highly Efficient Thermally Activated Delayed Fluorescence in Carbene Zinc(II) Dithiolates

Luminescent metal complexes based on earth abundant elements are a valuable target to substitute 4d/5d transition metal complexes as triplet emitters in advanced photonic applications. Whereas CuI complexes have been thoroughly investigated in the last two decades for this purpose, no structure-property-relationships for efficient luminescence involving triplet excited states from ZnII complexes are established. Herein, we report on the design of monomeric carbene zinc(II) dithiolates (CZT) featuring a donor-acceptor-motif that leads to highly efficient thermally activated delayed fluorescence (TADF) with for ZnII compounds unprecedented radiative rate constants kTADF =1.2×106  s-1 at 297 K. Our high-level DFT/MRCI calculations revealed that the relative orientation of the ligands involved in the ligand-to-ligand charge transfer (1/3 LLCT) states is paramount to control the TADF process. Specifically, a dihedral angle of 36-40° leads to very efficient reverse intersystem-crossing (rISC) on the order of 109  s-1 due to spin-orbit coupling (SOC) mediated by the sulfur atoms in combination with a small ΔES1-T1 of ca. 56 meV.

Synthesis, Structural Characterization, and Phosphorescence Properties of Trigonal Zn(II) Carbene Complexes

The sterically demanding N-heterocyclic carbene ITr (N,N'-bis(triphenylmethyl)imidazolylidene) was employed for the preparation of novel trigonal zinc(II) complexes of the type [ZnX2(ITr)] [X = Cl (1), Br (2), and I (3)], for which the low coordination mode was confirmed in both solution and solid state. Because of the atypical coordination geometry, the reactivity of 1-3 was studied in detail using partial or exhaustive halide exchange and halide abstraction reactions to access [ZnLCl(ITr)] [L = carbazolate (4), 3,6-di-tert-butyl-carbazolate (5), phenoxazine (6), and phenothiazine (7)], [Zn(bdt)(ITr)] (bdt = benzene-1,2-dithiolate) (8), and cationic [Zn(μ2-X)(ITr)]2[B(C6F5)4]2 [X = Cl (9), Br (10), and I (11)], all of which were isolated and structurally characterized. Importantly, for all complexes 4-11, the trigonal coordination environment of the ZnII ion is maintained, demonstrating a highly stabilizing effect due to the steric demand of the ITr ligand, which protects the metal center from further ligand association. In addition, complexes 1-3 and 8-11 show long-lived luminescence from triplet excited states in the solid state at room temperature, according to our photophysical studies. Our quantum chemical density functional theory/multireference configuration interaction (DFT/MRCI) calculations reveal that the phosphorescence of 8 originates from a locally excited triplet state on the bdt ligand. They further suggest that the phenyl substituents of ITr are photochemically not innocent but can coordinate to the electron-deficient metal center of this trigonal complex in the excited state.

A fast machine learning dataloader for epigenetic tracks from BigWig files

SUMMARY

We created bigwig-loader, a data-loader for epigenetic profiles from BigWig files that decompresses and processes information for multiple intervals from multiple BigWig files in parallel. This is an access pattern needed to create training batches for typical machine learning models on epigenetics data. Using a new codec, the decompression can be done on a graphical processing unit (GPU) making it fast enough to create the training batches during training, mitigating the need for saving preprocessed training examples to disk.

AVAILABILITY AND IMPLEMENTATION

The bigwig-loader installation instructions and source code can be accessed at https://github.com/pfizer-opensource/bigwig-loader.

Towards Fast Circularly Polarized Luminescence in 2-Coordinate Chiral Mechanochromic Copper(I) Carbene Complexes

A series of chiral mechanochromic copper(I) cAAC (cAAC=cyclic (alkyl)(amino)carbene) complexes with a variety of amide ligands have been studied with regard to their photophysical and chiroptical properties to elucidate structure-property relationships for the design of efficient triplet exciton emitters exhibiting circularly polarized luminescence. Depending on the environment, which determines the excited state energies, either thermally activated delayed fluorescence (TADF) from 1/3 LLCT states or phosphorescence from 3 LLCT/LC states occurs. However, neither chiral moieties at the carbene nor at the carbazolate ligands provide detectable luminescence dissymmetries glum . An exception is [Cu(phenoxazinyl)(cAAC)], showing orange to deep red TADF with λmax =601-715 nm in solution, powders and in PMMA. In this case, the amide ligand can undergo distortions in the excited state. This design motif leads to the first linear, non-aggregated CPL-active copper(I) complex with glum of -3.4 ⋅ 10-3 combined with a high radiative rate constant of 6.7 ⋅ 105  s-1 .

Fast and Tunable Phosphorescence from Organic Ionic Crystals

Crystalline diphosphonium iodides [MeR2 P-spacer-R2 Me]I with phenylene (1, 2), naphthalene (3, 4), biphenyl (5) and anthracene (6) as aromatic spacers, are photoemissive under ambient conditions. The emission colors (λem values from 550 to 880 nm) and intensities (Φem reaching 0.75) are defined by the composition and substitution geometry of the central conjugated chromophore motif, and the anion-π interactions. Time-resolved and variable-temperature luminescence studies suggest phosphorescence for all the titled compounds, which demonstrate observed lifetimes of 0.46-92.23 μs at 297 K. Radiative rate constants kr as high as 2.8×105  s-1 deduced for salts 1-3 were assigned to strong spin-orbit coupling enhanced by an external heavy atom effect arising from the anion-π charge-transfer character of the triplet excited state. These rates of anomalously fast metal-free phosphorescence are comparable to those of transition metal complexes and organic luminophores that utilize triplet excitons via a thermally activated delayed fluorescence mechanism, making such ionic luminophores a new paradigm for the design of photofunctional and responsive molecular materials.

Cellenium-a scalable and interactive visual analytics app for exploring multimodal single-cell data

SUMMARY

Multimodal single-cell sequencing data provide detailed views into the molecular biology of cells. To allow for interactive analyses of such rich data and to readily derive insights from it, new analysis solutions are required. In this work we present Cellenium, our new scalable visual analytics web application which enables users to semantically integrate and organize all their single-cell RNA-, ATAC-, and CITE-sequencing studies. Users can then find relevant studies and analyze single-cell data within and across studies. An interactive cell annotation feature allows for adding user-defined cell types.

AVAILABILITY AND IMPLEMENTATION

Source code and documentation are freely available under an MIT license and are available on GitHub (https://github.com/Bayer-Group/cellenium). The server backend is implemented in PostgreSQL, Python 3 and GraphQL, the frontend is written in ReactJS, TypeScript and Mantine css, plots are generated using plotlyjs, seaborn, vega-lite and nivo.rocks. The application is dockerized and can be deployed and orchestrated on a standard workstation via docker-compose.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

From Terminal to Spiro-Phosphonium Acceptors, Remarkable Moieties to Develop Polyaromatic NIR Dyes

Phosphonium-based compounds gain attention as a promising photofunctional materials. As a contribution to the emerging field, we present a series of donor-acceptor ionic dyes, which were constructed by tailoring the phosphonium (A) and extended π-NR2 (D) fragments to the anthracene framework. The alteration of the π-spacer of electron-donating substituents in species with terminal -+PPh2Me groups exhibits a long absorption wavelength up to λabs = 527 nm in dichloromethane and shifted the emission to the near-infrared (NIR) region (λ = 805 nm for thienyl aniline donor), although at low quantum yield (Φ < 0.01). In turn, the introduction of a P-heterocyclic acceptor substantially narrowed the optical bandgap and improved the efficiency of fluorescence. In particular, the phospha-spiro moiety allowed to attain NIR emission (797 nm in dichloromethane) with fluorescence efficiency of as high as Φ = 0.12. The electron-accepting property of phospha-spiro constituent outperformed that of the monocyclic and terminal phosphonium counterparts, illustrating a promising direction in the design of novel charge transfer chromophores.

Mechano-Stimulus and Environment-Dependent Circularly Polarized TADF in Chiral Copper(I) Complexes and Their Application in OLEDs

Molecular emitters that combine circularly polarized luminescence (CPL) and high radiative rate constants of the triplet exciton decay are highly attractive for electroluminescent devices (OLEDs) or next-generation photonic applications, such as spintronics, quantum computing, cryptography, or sensors. However, the design of such emitters is a major challenge because the criteria for enhancing these two properties are mutually exclusive. In this contribution, we show that enantiomerically pure {Cu(Cbz^R)[(S/R)-BINAP]} [R = H (1), 3,6-tBu (2)] are efficient thermally activated delayed fluorescence (TADF) emitters with high radiative rate constants of k_TADF up to 3.1 × 10⁵ s^-1 from ^1/3LLCT states according to our temperature-dependent time-resolved luminescence studies. The efficiency of the TADF process and emission wavelengths are highly sensitive to environmental hydrogen bonding of the ligands, which can be disrupted by grinding of the crystalline materials. The origin of this pronounced mechano-stimulus photophysical behavior is a thermal equilibrium between the ^1/3LLCT states and a ³LC state of the BINAP ligand, which depends on the relative energetic order of the excited states and is prone to inter-ligand C-H···π interactions. The copper(I) complexes are also efficient CPL emitters displaying exceptional dissymmetry values g_lum of up to ±0.6 × 10^-2 in THF solution and ±2.1 × 10^-2 in the solid state. Importantly for application in electroluminescence devices, the C-H···π interactions can also be disrupted by employing sterically bulky matrices. Accordingly, we have investigated various matrix materials for successful implementation of the chiral copper(I) TADF emitters in proof-of-concept CP-OLEDs.

Use of drug-induced sleep endoscopy in Germany-an analysis based on claims data

Background

Drug-induced sleep endoscopy (DISE) has recently gained relevance as a diagnostic tool for obstructive sleep apnea (OSA). However, it is unclear to what extent and in which patient cohorts DISE is used in Germany. With introduction of specific coding for this method in 2021 (Operationen- und Prozedurenschluessel, OPS code), usage can now be analyzed based on diagnosis-related groups (DRG) claims data.

Methods

Aggregated data from all inpatient DISE procedures conducted in German hospitals in 2021 were obtained from the publicly available Institut fuer das Entgeltsystem im Krankenhaus (InEK) database. Patient-relevant information as well as data on hospitals providing the examinations were exported and analyzed.

Results

Between January and December 2021, a total of 2765 DISE procedures were conducted and documented using the newly introduced specific code (1-611.01). Most patients were male (75.6%), in the age categories 30-39 (15.2%) and 40-49 years (17.2%), and presented with the lowest patient clinical complexity level (PCCL; class 0 = 81.88%). Pediatric use was rare (1.8%). Leading main diagnoses of patients were G47.31 (OSA) and J34.2 (deviation of nasal septum). The most common procedures conducted together with DISE were nasal surgery, and the examination was mostly provided in large public hospitals with more than 800 beds.

Conclusion

Though the OSA prevalence in Germany is high, use of DISE as a diagnostic tool is low and represented only 4.4% of cases with a main diagnosis of OSA in 2021. Since specific coding was only introduced in January 2021, trends cannot yet be identified. Noticeable is the frequent combination of DISE with nasal surgery, which is not obviously related to a diagnosis of OSA. Limitations of the study are mainly related to the underlying data, which are available for the inpatient sector only, and due to potentially limited use of the OPS code, which was introduced recently and might not be known to all hospitals.

An Air- and Moisture-stable Zinc(II) Carbene Dithiolate Dimer Showing Fast Thermally Activated Delayed Fluorescence and Dexter Energy Transfer Catalysis

A dimeric Zn^II carbene complex featuring bridging and chelating benzene-1,2-dithiolate ligands is highly stable towards air and water. The donor-Zn-acceptor structure leads to visible light emission in the solid state, solution and polymer matrices with λ_max between 577-657 nm and, for zinc(II) complexes, unusually high radiative rate constants for triplet exciton decay of up to k_r =1.5×10⁵  s^-1 at room temperature. Variable temperature and DFT/MRCI studies show that a small energy gap between the ^1/3 LL/LMCT states of only 79 meV is responsible for efficient thermally activated delayed fluorescence (TADF). Time-resolved luminescence and transient absorption studies confirm the occurrence of long-lived, dominantly ligand-to-ligand charge transfer excited states in solution, allowing for application in Dexter energy transfer photocatalysis.

Finding Design Principles of OLED Emitters through Theoretical Investigations of Zn(II) Carbene Complexes

In this work, Zn(II) carbene complexes carrying a dianionic 1,2-dithiolbenzene (dtb) or 1,2-diolbenzene (dob) ligand were investigated regarding their suitability as organic light-emitting diode (OLED) emitter. For the optimization of the complexes, density functional-based methods were used and frequency analyses verified the obtained structures as minima. All calculations were carried out including a polarizable continuum model to mimic solvent-solute interactions. Multireference configuration interaction methods were used to determine excitation energies, spin-orbit couplings, and luminescence properties. Rate constants of spin-allowed and spin-forbidden transitions were calculated according to a Fermi golden rule expression. Using carbene ligands with varying σ-donor and π-acceptor strengths, the luminescence is found to be tunable from yellow to orange/red to deep red/near-infrared. The calculated intersystem crossing (ISC) time constants indicate thermally activated delayed fluorescence (TADF) to be the main decay channel. In contrast to many d¹⁰ coinage metal complexes, a parallel orientation of dtb or dob and the carbene ligand is found to be highly favorable. For the complexes with a cyclic (alkyl)(amino) carbene (CAAC) or cyclic (amino)(aryl) carbene (CAArC) ligand, the S₁ and T₁ states have ligand-to-ligand charge-transfer (LLCT) character and are energetically close. The complex with a classical N-heterocyclic carbene (NHC) ligand has S₁ and T₁ states with mixed ligand-to-metal charge-transfer (LMCT)/LLCT character and is a very rare example in which the zinc ion contributes to the excitation.

Trigonal Copper(I) Complexes with Cyclic (Alkyl)(amino)carbene Ligands for Single-Photon Near-IR Triplet Emission

Molecular near-IR (NIR) triplet-state emitters are of importance for the development of new, organic-electronics-based telecommunication technologies as optical fibers operating in the corresponding spectral bands allow for data transfer over much longer distances due to the significantly lower attenuation. However, achieving such low-energy triplet excited states with good radiative rate constants is very challenging, and studies regarding the single-photon emission of organometallics in this energy range are scarce. We have prepared a series of trigonal Cu^I CAAC complexes bearing chelating ligands with O, N, S, and Se donor atoms and studied their photophysical properties in this context. The compounds show weak low-energy absorption in solution between 400 and 500 nm due to mixed Cu → CAAC ¹MLCT/LLCT states, resulting in yellow-green to orange appearance, which we have also correlated to the ¹⁵N NMR resonances of the π-accepting carbene ligand. In the solid state, phosphorescence from dominant ³(Cu → CAAC) CT states is observed at room temperature. The emission of the complexes is bathochromically shifted in comparison to structurally related linearly coordinated copper(I) CAAC complexes due to structural reorganization in the excited state to a T-shape. For [Cu(dbm)(CAAC^Me)], the broad phosphorescence with outstanding λ_max = 760 nm tailors out to ca. 1100 nm and leads to its proof-of-concept application as a nonclassical single-photon light source, constituting key functional units for the implementation of tap-proof data transfer.

Ultra-Long Lived Luminescent Triplet Excited States in Cyclic (Alkyl)(amino)carbene Complexes of Zn(II) Halides

The high element abundance and d¹⁰ electron configuration make Zn^II‐based compounds attractive candidates for the development of novel photoactive molecules. Although a large library of purely fluorescent compounds exists, emission involving triplet excited states is a rare phenomenon for zinc complexes. We have investigated the photophysical and ‐chemical properties of a series of dimeric and monomeric Zn^II halide complexes bearing a cyclic (alkyl)(amino)carbene (cAAC) as chromophore unit. Specifically, [(cAAC)XZn(μ‐X)₂ZnX(cAAC)] (X=Cl (1), Br (2), I (3)) and [ZnX₂(cAAC)(NCMe)] (X=Br (4), I (5)) were isolated and fully characterized, showing intense visible light photoluminescence under UV irradiation at 297 K and fast photo‐induced transformation. At 77 K, the compounds exhibit improved stability allowing to record ultra‐long lifetimes in the millisecond regime. DFT/MRCI calculations confirm that the emission stems from ³XCT/LE_cAAC states and indicate the phototransformation to be related to asymmetric distortion of the complexes by cAAC ligand rotation. This study enhances our understanding of the excited state properties for future development and application of new classes of Zn^II phosphorescent complexes.

Identification of a Neural Development Gene Expression Signature in Colon Cancer Stem Cells Reveals a Role for EGR2 in Tumorigenesis

Recent evidence demonstrates that colon cancer stem cells (CSCs) can generate neurons that synapse with tumor innervating fibers required for tumorigenesis and disease progression. Greater understanding of the mechanisms that regulate CSC driven tumor neurogenesis may therefore lead to more effective treatments. RNA-sequencing analyses of ALDH^Positive CSCs from colon cancer patient-derived organoids (PDOs) and xenografts (PDXs) showed CSCs to be enriched for neural development genes. Functional analyses of genes differentially expressed in CSCs from PDO and PDX models demonstrated the neural crest stem cell (NCSC) regulator EGR2 to be required for tumor growth and to control expression of homebox superfamily embryonic master transcriptional regulator HOX genes and the neural stem cell and master cell fate regulator SOX2. These data support CSCs as the source of tumor neurogenesis and suggest that targeting EGR2 may provide a therapeutic differentiation strategy to eliminate CSCs and block nervous system driven disease progression.

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Colon cancer stem cells (CSCs) are enriched for nervous system development genes

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Colon cancer cells express nerve cell markers

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EGR2 is required for CSC survival and tumor growth and regulates SOX2 and HOX genes

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Targeting EGR2 may block cancer neurogenesis and stop disease progression

Linear Carbene Pyridine Copper Complexes with Sterically Demanding N,N'-Bis(trityl)imidazolylidene: Syntheses, Molecular Structures, and Photophysical Properties

The sterically demanding carbene ITr (N,N'-bis(triphenylmethyl)imidazolylidene) was used as a ligand for the preparation of luminescent copper(I) complexes of the type [(ITr)Cu(R-pyridine/R'-quinoline)]BF₄ (R = H, 4-CN, 4-CHO, 2,6-NH₂, and R' = 8-Cl, 6-Me). The selective formation of linear, bis(coordinated) complexes was observed for a series of pyridine and quinoline derivatives. Only in the case of 4-cyanopyridine a one-dimensional coordination polymer was formed, in which the cyano group of the cyanopyridine ligand additionally binds to another Cu atom in a bridging manner, thus leading to a trigonal planar coordination environment. In contrast, employing sterically less demanding monotrityl-substituted carbene 3, no (NHC)Cu-pyridine complexes could be prepared. Instead, a bis-carbene complex [(3)₂Cu]PF₆ was obtained which showed no luminescence. All linear pyridine/quinoline coordinated complexes show weak emission in solution but intense blue to orange luminescence doped with 10% in PMMA films and in the solid state either from triplet excited states with unusually long lifetimes of up to 4.8 ms or via TADF with high radiative rate constants of up to 1.7 × 10⁵ s^-1 at room temperature. Combined density functional theory and multireference configuration interaction calculations have been performed to rationalize the involved photophysics of these complexes. They reveal a high density of low-lying electronic states with mixed MLCT, LLCT, and LC character where the electronic structures of the absorbing and emitting state are not necessarily identical.

Ditopic Phosphide Oxide Group: A Rigidifying Lewis Base to Switch Luminescence and Reactivity of a Disilver Complex

Heterodentate phosphines containing anionic organophosphorus groups remain virtually unexplored ligands in the coordination chemistry of coinage metals. A hybrid phosphine-phosphine oxide (o-Ph₂PC₆H₄)₂P(O)H (HP³O) readily forms the disilver complex [Ag₂(P³O)₂] (1) upon deprotonation of the (O)P-H fragment. Due to the electron-rich nature, the anionic phosphide oxide unit in 1 takes part in efficient intermolecular hydrogen bonding, which has an unusual and remarkably strong impact on the photoluminescence of 1, changing the emission from red (644 nm) to green-yellow (539 nm) in the solid. The basicity of the R₂(O)P^- group and its affinity for both inter- and intramolecular donor-acceptor interactions allow converting 1 into hydrohalogenated (2, 3) and boronated (4) derivatives, which reveal a gradual hypsochromic shift of luminescence, reaching the wavelength of 489 nm. Systematic variable-temperature analysis of the excited state properties suggests that thermally activated delayed fluorescence is involved in the emission process. The long-lived excited states for 1-4, the energy of which is largely regulated by means of the phosphide oxide unit, are potentially suitable for triplet energy transfer photocatalysis. With the highest T₁ energy among 1-4, complex 4 demonstrates excellent photocatalytic activity in a [2+2] cycloaddition reaction, which has been realized for the first time for silver(I) compounds.

Simple Synthetic Routes to Carbene-M-Amido (M=Cu, Ag, Au) Complexes for Luminescence and Photocatalysis Applications

The development of novel and operationally simple synthetic routes to carbene‐metal‐amido (CMA) complexes of copper, silver and gold relevant for photonic applications are reported. A mild base and sustainable solvents allow all reactions to be conducted in air and at room temperature, leading to high yields of the targeted compounds even on multigram scales. The effect of various mild bases on the N−H metallation was studied in silico and experimentally, while a mechanochemical, solvent‐free synthetic approach was also developed. Our photophysical studies on [M(NHC)(Cbz)] (Cbz=carbazolyl) indicate that the occurrence of fluorescent or phosphorescent states is determined primarily by the metal, providing control over the excited state properties. Consequently, we demonstrate the potential of the new CMAs beyond luminescence applications by employing a selected CMA as a photocatalyst. The exemplified synthetic ease is expected to accelerate the applications of CMAs in photocatalysis and materials chemistry.

RNA sequencing of long-term label-retaining colon cancer stem cells identifies novel regulators of quiescence

Recent data suggest that therapy-resistant quiescent cancer stem cells (qCSCs) are the source of relapse in colon cancer. Here, using colon cancer patient-derived organoids and xenografts, we identify rare long-term label-retaining qCSCs that can re-enter the cell cycle to generate new tumors. RNA sequencing analyses demonstrated that these cells display the molecular hallmarks of quiescent tissue stem cells, including expression of p53 signaling genes, and are enriched for transcripts common to damage-induced quiescent revival stem cells of the regenerating intestine. In addition, we identify negative regulators of cell cycle, downstream of p53, that we show are indicators of poor prognosis and may be targeted for qCSC abolition in both p53 wild-type and mutant tumors. These data support the temporal inhibition of downstream targets of p53 signaling, in combination with standard-of-care treatments, for the elimination of qCSCs and prevention of relapse in colon cancer.

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Colon tumors contain therapy-resistant quiescent cancer stem cells (qCSCs)

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qCSC gene expression mirrors that of quiescent stem cells of the regenerating gut

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qCSCs are enriched for p53 signaling genes

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qCSC elimination may be achieved by inhibiting downstream targets of p53 signaling

Abstract 1807: Anti-tumor activity of a novel structural class of NAMPT inhibitor-based ADCs in models of hematologic and solid tumor indications

Nicotinamide phosphoribosyl-transferase (NAMPT) is the rate-limiting enzyme in the salvage pathway, generating nicotinamide adenine dinucleotide (NAD) from nicotinamide (NAM). Inhibition of intracellular NAMPT activity represents a differentiated mode-of-action for tumor-targeting antibody-drug conjugates (ADCs) as it is not dependent on cell proliferation. Thus, NAMPT inhibitor-based ADCs have the potential to target both proliferating and resting tumor cells. We therefore developed a novel structural class of NAMPT inhibitors (NAMPTi) as a potent ADC payload class and characterized NAMPTi and NAMPTi-ADCs in vitro and in vivo in preclinical tumor models. We profiled the small molecule NAMPTi BAY-346 in comparison to the kinesin spindle protein inhibitor (KSPi) BAY-331 on a panel of 350 cancer cell lines from various tumor indications showing a differential sensitivity profile of BAY-346 vs BAY-331, with cell lines characterized by low NAMPT mRNA levels as being very sensitive to BAY-346. NAMPTi BAY-346, but not KSPi BAY-331, reduced the viability of quiescent HaCat cells as well as of serum starved non-proliferating NCI-N87 cells. In vitro treatment with NAMPTi BAY-346, which bears a pyridine warhead that can be phosphoribosylated by NAMPT, resulted in IC50 values in the nanomolar to subnanomolar range (2.8 nM to 0.01 nM) in cell lines derived from solid and hematologic tumor indications (e.g., THP-1, MV-4-11, U-251, NCI-H292, MDA-MB-453, LoVo, KPL4, HT1197 and BxPC3). BAY-346 was 100-fold more potent than the small molecule NAMPTi BAY-248, which cannot be phosphoribosylated. A BAY-346 derived NAMPTi was conjugated as a payload to a series of antibodies targeting different tumor-associated antigens: C4.4a (LYPD3), HER2, B7H3 (CD276), and TWEAKR (Fn14/ TNFRSF10A). The resulting NAMPTi-ADCs were tested in proliferation and cellular mechanistic in vitro assays. NAMPTi-ADCs depleted NAD+ in tumor cells and showed potent growth inhibitory activity with IC50 values in the subnanomolar- to nanomolar range in a target-dependent manner. A C4.4a-NAMPTi-ADC and a HER2-NAMPTi-ADC were tested In the C4.4a- and HER2-expressing MDA-MB-453 cell line derived subcutaneous breast cancer model xenografted on NOD/SCID mice. Both NAMPTi-ADCs showed highly potent anti-tumor Efficacy: The C4.4a-NAMPTi-ADC induced complete responses (in 3 of 8 mice) and stable diseases (in 5 of 8 mice) and the HER2-NAMPTi-ADC achieved complete tumor regression in all treated animals. In addition, in the THP-1 acute myeloid leukemia (AML) subcutaneous in vivo model, a B7H3-NAMPTi-ADC induced complete tumor responses in 7 of 8 treated animals. Taken together, we identified a new series of NAMPT inhibitors as a novel class of ADC payloads exhibiting strong in vivo efficacy in various preclinical xenograft models.

Citation Format: Anette Sommer, Stefanie Hammer, Sandra Berndt, Antje M. Wengner, Niels Boehnke, Markus Berger, Nils Griebenow, Andreas Steffen, Beatrix Stelte-Ludwig, Christoph Mahlert, Simone Greven, Lisa Dietz, Hannah Joerissen, Anja Giese, Maria Quanz, Zhengzheng Bao, Xiuli Wu, Hilmar Weinmann, Lars Linden, Bertolt Kreft, Dominik Mumberg. Anti-tumor activity of a novel structural class of NAMPT inhibitor-based ADCs in models of hematologic and solid tumor indications [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1807.

Direct observation of o-benzyne formation in photochemical hexadehydro-Diels-Alder (hν-HDDA) reactions

Reactive ortho-benzyne derivatives are believed to be the initial products of liquid-phase [4 + 2]-cycloadditions between a 1,3-diyne and an alkyne via what is known as a hexadehydro-Diels–Alder (HDDA) reaction. The UV/VIS spectroscopic observation of o-benzyne derivatives and their photochemical dynamics in solution, however, have not been reported previously. Herein, we report direct UV/VIS spectroscopic evidence for the existence of an o-benzyne in solution, and establish the dynamics of its formation in a photoinduced reaction. For this purpose, we investigated a bis-diyne compound using femtosecond transient absorption spectroscopy in the ultraviolet/visible region. In the first step, we observe excited-state isomerization on a sub-10 ps time scale. For identification of the o-benzyne species formed within 50–70 ps, and the corresponding photochemical hexadehydro-Diels–Alder (hν-HDDA) reactions, we employed two intermolecular trapping strategies. In the first case, the o-benzyne was trapped by a second bis-diyne, i.e., self-trapping. The self-trapping products were then identified in the transient absorption experiments by comparing their spectral features to those of the isolated products. In the second case, we used perylene for trapping and reconstructed the spectrum of the trapping product by removing the contribution of irrelevant species from the experimentally observed spectra. Taken together, the UV/VIS spectroscopic data provide a consistent picture for o-benzyne derivatives in solution as the products of photo-initiated HDDA reactions, and we deduce the time scales for their formation.

We report the transient ultraviolet/visible absorption spectrum of an o-benzyne species in solution for the first time.

Abstract A29: Genome-wide CRISPR/Cas9 screens for the identification of novel YAP1/TAZ modulators

Aberrant activation of the Hippo pathway effectors YAP1/TAZ promotes cell proliferation and tumorigenesis. To identify novel regulators of YAP1/TAZ in cancer, we established a FACS-based screening system monitoring YAP1/TAZ activity in MDA-MB-231 breast cancer cells. Using these cells, we performed pooled genome-wide CRISPR/Cas9 knockout and CRISPR activation/interference (a/i) screens. The list of hits included previously known YAP1/TAZ modulators such as LATS2, AJUBA, and TAZ itself, demonstrating the robustness of the screen. Moreover, we identified about 30 novel candidate genes with potential inhibitory activity on YAP1/TAZ and about 50 candidate genes that may play a role in YAP1/TAZ activation. These genes represent diverse cellular functions such as regulation of actin cytoskeleton, integrin signaling, and ER protein processing, among others. Modulation of endogenous YAP1/TAZ target genes was assessed by individual gene knockout using crRNAs. Functional characterization of the novel potential YAP1/TAZ modulators will aid to the further understanding of YAP1/TAZ biology in health and disease.

Citation Format: Jan Naujoks, Lisette Potze, Julia Kuehnlenz, Atanas Kamburov, Ekaterina Nevedomskaya, Andreas Steffen, Claudia Luther, Anna Anurin, Anne Buttgereit, Stefan Prechtl, Benjamin Bader, Ralf Lesche, Peter Staller, Martin Lange, Barbara Nicke. Genome-wide CRISPR/Cas9 screens for the identification of novel YAP1/TAZ modulators [abstract]. In: Proceedings of the AACR Special Conference on the Hippo Pathway: Signaling, Cancer, and Beyond; 2019 May 8-11; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(8_Suppl):Abstract nr A29.

Diagnosis and treatment of isolated snoring-open questions and areas for future research

STUDY OBJECTIVES

Snoring is a common phenomenon which is generated by vibration of soft tissue of the upper airway during sleep. Due to the high incidence of isolated snoring and the substantial burden for the patient and the bed partner, a thorough examination and appropriate therapy are required. Many recommendations for the treatment of isolated snoring are either not evidence-based or are derived from recommendations for the management of obstructive sleep apnea. Therefore, the aim of this study is the identification and description of open questions in the diagnosis and treatment of isolated snoring and the illustration of areas for further research.

METHODS

In the context of the development of the new version of the German guideline "Diagnosis and treatment of isolated snoring in adults," a multidisciplinary team of experts performed a systematic literature search on the relevant medical data and rated the current evidence regarding the key diagnostic and therapeutic measures for snoring.

RESULTS

The systematic literature review identified 2293 articles. As a major inclusion criterion, only studies on primary snoring based on objective sleep medical assessment were selected. After screening and evaluation, 33 full-text articles remained for further analysis. Based on these articles, open questions and areas for future research were identified for this review.

CONCLUSION

Several major gaps in the literature on the diagnosis and treatment of isolated snoring were identified. For the majority of diagnostic and therapeutic measures for snoring, high-level scientific evidence is still lacking.

grünifai: interactive multiparameter optimization of molecules in a continuous vector space

SUMMARY

Optimizing small molecules in a drug discovery project is a notoriously difficult task as multiple molecular properties have to be considered and balanced at the same time. In this work, we present our novel interactive in silico compound optimization platform termed grünifai to support the ideation of the next generation of compounds under the constraints of a multiparameter objective. grünifai integrates adjustable in silico models, a continuous representation of the chemical space, a scalable particle swarm optimization algorithm and the possibility to actively steer the compound optimization through providing feedback on generated intermediate structures.

AVAILABILITY AND IMPLEMENTATION

Source code and documentation are freely available under an MIT license and are openly available on GitHub (https://github.com/jrwnter/gruenifai). The backend, including the optimization method and distribution on multiple GPU nodes is written in Python 3. The frontend is written in ReactJS.

0869 Slow Wave Sleep Is Associated With Decreased Risk Of Gestational Diabetes Mellitus

Introduction

Pregnancy is associated with disrupted slow-wave sleep (SWS) and a high prevalence of sleep disordered breathing (SDB), which may further exacerbate the decrease of deep sleep. Reduced slow wave sleep may impair glucose homeostasis, contributing to Gestational Diabetes Mellitus (GDM). Studies investigating EEG markers of deep and light sleep, and their associations with SDB and GDM are lacking. In this study, we measured associations of EEG Delta-power with objective SDB measures assessed in late-pregnancy to determine if changes in these bands are associated with GDM risk.

Methods

74 women (24-36 weeks pregnancy) underwent overnight polysomnography. Spectral profiles for Delta relative power were created for NREM and REM sleep after removing epochs with movements or muscle artifacts. The association of Delta power with SDB, assessed by the Apnea Hypopnea-Index (AHI) and AHI-based SDB severity (none, mild, moderate, severe) was tested by multivariate linear regression including demographic variables with bivariate correlations (p&lt;0.2) versus Delta-power. Conditional-regression was used to explore relationships between Delta-power and GDM, controlling for covariates.

Results

Obstructive Sleep Apnea (OSA, AHI&gt;5) was present in 14% of subjects (8 GDM-cases and 3 controls). In bivariate analyses, AHI, AHI-severity categories and OSA were associated with Delta-power in NREM (all p&lt;0.2) and AHI was associated with Delta relative-power in REM (p=0.18). However, these associations did not remain significant after adjusting for covariates. Delta relative-power in NREM was significantly associated with decreased risk of GDM (OR:0.50, 95%CI-0.25,0.91), but, in REM sleep, was not associated with GDM risk (OR:1.25, 95%CI-0.79,1.97).

Conclusion

These analyses failed to demonstrate an association between OSA or OSA severity and EEG Delta power. However, lower levels of SWS, characterized by low Delta power were associated with increased GDM risk.

Support

NIH-R00-NR013187

0529 Behavioral Therapy Components for Insomnia and Fatigue in COPD

Introduction

Insomnia contributes to fatigue, a common symptom in COPD. Our study aims were: (1) to determine the efficacy of a) cognitive behavioral therapy for insomnia (CBT-I) and b) COPD education (COPD-ED) on insomnia and fatigue, and (2) to define potential mechanistic contributors to pre/post intervention change in insomnia and fatigue in patients with COPD and insomnia.

Methods

A randomized 2x2 factorial design was used with factors representing CBT-I (yes/no) and COPD-ED (yes/no). Attention control (health videos) were used in the absence of CBT-I or COPD-ED. All patients received 6, 75-minute weekly sessions. Dependent variables included insomnia severity (Sleep Impairment Index (SII), range 0-28) and fatigue (Chronic Respiratory Disease Questionnaire (CRQ) range 1-7) measured at baseline, just post-intervention, and at 3-months post-intervention.

Results

One hundred nine patients (FEV1% predicted 67 ± 24% (mean ± SD), age 65 ± 8 years, SII 15.9 ± 8, CRQ 3.7 ± 1.1) participated in the study. After 6 sessions, insomnia decreased more in patients who received CBT-I (-5.8) than those who did not (-2.2; p=0.0002). This effect was sustained at the 3-month follow-up (p=0.0003). Fatigue showed no significant differences for CBT-I at 6-weeks (p=.27) but at 3-months patients receiving CBT-I showed marginally better improvement (.75, a clinically important difference) compared to those who did not receive CBT-I (.43; p=.09). COPD-ED showed no effect on insomnia or fatigue. Two main effects suggest mechanisms for the pre-post efficacy of CBT-I: improved sleep beliefs (p=0.0257) and self-efficacy for sleep (p=0.0619) after 6 sessions which were sustained at 3 months (p=0.0184 and p=0.0431 respectively).

Conclusion

CBT-I produced sustained decreases in insomnia in patients with COPD. Results suggest that changes in beliefs about sleep and improved self-efficacy for managing sleep may mediate CBT-I associated decreases in insomnia.

Support

This research was supported by the National Institute of Nursing Research of the National Institutes of Health R01NR013937.

0674 Association Between Lateral Wall Collapse On Drug-induced Sleep Endoscopy And MRI Findings In Hypoglossal Nerve Stimulator Patients

Introduction

Hypoglossal nerve stimulator (HNS) is an effective and safe alternative therapy for obstructive sleep apnea (OSA) in selected patients. Emerging evidence demonstrates that the outcome of HNS is variable, especially for patients with lateral wall collapse on drug-induced sleep endoscopy (DISE). Awake magnetic resonance imaging (MRI) offers detailed visualization of soft tissue. The aim of this study was to determine whether lateral wall collapse on DISE is associated with awake MRI findings in prospective HNS patients.

Methods

Patients from the ADHERE Registry, an international outcomes study for UAS were used for this study. At baseline, awake, supine MRI scans of each subject’s head and neck region were collected. The distance between the lateral walls was measured at the level of the hard palate, located by the appearance of the posterior nasal spine, using axial T2 turbo spin echo MRI. DISE assessments of the upper airway were recorded using the VOTE classification. All statistical analyses were performed using SPSS IBM 19.0 software program. Kendall’s Tau-b was performed to compare the association between VOTE scoring and MRI findings.

Results

Twenty-seven patients (N = 3 female, AHI = 28.8±10.5, BMI = 28.8 ±3.8 kg/m2, age = 53±9.9 years) were included in this study. The mean overall VOTE score and lateral wall score was 5.6±1.1 and 0.5±0.5, respectively. The mean lateral wall distance was 18.8±3.2 mm. A significant, inverse association was found between MRI lateral wall measurement and oropharyngeal lateral wall scoring on DISE (T=-.332,p=0.042) but not other anatomic subsites on DISE.

Conclusion

In our study, greater lateral wall collapse on DISE corresponded to narrower lateral airway distance on MRI. The utility of static imaging modalities such as MRI as patient selection tools for HNS warrants further study.

Support

Drs. Dedhia and Schwab receive related support for this project from the National Institutes of Health (NHBLI R01HL144859)

Cyclic (Amino)(aryl)carbenes Enter the Field of Chromophore Ligands: Expanded π System Leads to Unusually Deep Red Emitting CuI Compounds

A series of copper(I) complexes bearing a cyclic (amino)(aryl)carbene (CAArC) ligand with various complex geometries have been investigated in great detail with regard to their structural, electronic, and photophysical properties. Comparison of [CuX(CAArC)] (X = Br (1), Cbz (2), acac (3), Ph₂acac (4), Cp (5), and Cp* (6)) with known Cu^I complexes bearing cyclic (amino)(alkyl), monoamido, or diamido carbenes (CAAC, MAC, or DAC, respectively) as chromophore ligands reveals that the expanded π-system of the CAArC leads to relatively low energy absorption maxima between 350 and 550 nm in THF with high absorption coefficients of 5-15 × 10³ M^-1 cm^-1 for 1-6. Furthermore, 1-5 show intense deep red to near-IR emission involving their triplet excited states in the solid state and in PMMA films with λ^em_max = 621-784 nm. Linear [Cu(Cbz)(^DippCAArC)] (2) has been found to be an exceptional deep red (λ_max = 621 nm, ϕ = 0.32, τ_av = 366 ns) thermally activated delayed fluorescence (TADF) emitter with a radiative rate constant k_r of ca. 9 × 10⁵ s^-1, exceeding those of commercially employed Ir^III- or Pt^II-based emitters. Time-resolved transient absorption and fluorescence upconversion experiments complemented by quantum chemical calculations employing Kohn-Sham density functional theory and multireference configuration interaction methods as well as temperature-dependent steady-state and time-resolved luminescence studies provide a detailed picture of the excited-state dynamics of 2. To demonstrate the potential applicability of this new class of low-energy emitters in future photonic applications, such as nonclassical light sources for quantum communication or quantum cryptography, we have successfully conducted single-molecule photon-correlation experiments of 2, showing distinct antibunching as required for single-photon emitters.

Copper(I) Phosphinooxazoline Complexes: Impact of the Ligand Substitution and Steric Demand on the Electrochemical and Photophysical Properties

A series of seven homoleptic Cu^I complexes based on hetero-bidentate P^N ligands was synthesized and comprehensively characterized. In order to study structure-property relationships, the type, size, number and configuration of substituents at the phosphinooxazoline (phox) ligands were systematically varied. To this end, a combination of X-ray diffraction, NMR spectroscopy, steady-state absorption and emission spectroscopy, time-resolved emission spectroscopy, quenching experiments and cyclic voltammetry was used to assess the photophysical and electrochemical properties. Furthermore, time-dependent density functional theory calculations were applied to also analyze the excited state structures and characteristics. Surprisingly, a strong dependency on the chirality of the respective P^N ligand was found, whereas the specific kind and size of the different substituents has only a minor impact on the properties in solution. Most importantly, all complexes except C3 are photostable in solution and show fully reversible redox processes. Sacrificial reductants were applied to demonstrate a successful electron transfer upon light irradiation. These properties render this class of photosensitizers as potential candidates for solar energy conversion issues.

[Upper Airway Stimulation for obstructive sleep apnea-Can radiological position monitoring predict tongue motion one year after implantation? German version]

BACKGROUND

Tongue motion patterns (TMP) can influence the outcome of upper airway stimulation (UAS) in the treatment of obstructive sleep apnea (OSA). As a postoperative control the cuff position of the stimulation lead is monitored via X‑ray imaging. A multidimensional X‑ray assessment system was established and the association between these positional assessments and TMP was investigated 1 year after implantation.

MATERIAL AND METHODS

The study on TMP and the X‑ray assessments were carried out at a German ear nose and throat clinic as an implantation center. The TMPs were assessed under bipolar electrode configuration and were categorized according to the currently available literature as right-sided protrusion (RP), left-sided protrusion (LP), bilateral protrusion (BP) and mixed activation (MA). The X‑ray assessment was carried out in five dimensions: the position relative to the mandible and hyoid, cuff steepness in the lateral view of the neck, the cuff position based on the single electrode and the lead connection to the cuff in the anterior-posterior view. The analyses were performed by three raters with different medical backgrounds and knowledge regarding TMP.

RESULTS

In approximately 60% of the patients the apnea-hypopnea index was reduced to below 15/h, 1 year after implantation. The most common TMPs were RP and BP (82.9%). The interrater variability of the X‑ray assessment was good except for one category. Furthermore, no relevant associations were found apart from the correlation between a favorable TMP and the cuff position with respect to the lateral position of the stimulation cable.

CONCLUSION

Despite good interrater variability and convenient usage of the suggested X‑ray assessment system, this approach did not enable the identification of any associations, by which a TM and therefore a possible straightforward or complicated treatment pathway could be predicted. Attention should possibly be paid to a rotation of the cuff during implantation with a lateral position of the stimulation lead.

Efficient multi-objective molecular optimization in a continuous latent space

One of the main challenges in small molecule drug discovery is finding novel chemical compounds with desirable properties. In this work, we propose a novel method that combines in silico prediction of molecular properties such as biological activity or pharmacokinetics with an in silico optimization algorithm, namely Particle Swarm Optimization. Our method takes a starting compound as input and proposes new molecules with more desirable (predicted) properties. It navigates a machine-learned continuous representation of a drug-like chemical space guided by a defined objective function. The objective function combines multiple in silico prediction models, defined desirability ranges and substructure constraints. We demonstrate that our proposed method is able to consistently find more desirable molecules for the studied tasks in relatively short time. We hope that our method can support medicinal chemists in accelerating and improving the lead optimization process.

Synthesis, photophysical and electronic properties of tetra-donor- or acceptor-substituted ortho-perylenes displaying four reversible oxidations or reductions

Via regioselective Ir-catalyzed C-H borylation and subsequent reactions (i.e., via Br4-Per or (BF3K)4-Per intermediates), we have introduced strong π-donors and acceptors at the 2,5,8,11-positions of perylene leading to unusual properties. Thus, incorporation of four donor diphenylamine (DPA) or four acceptor Bmes2 (mes = 2,4,6-Me3C6H2) moieties yields novel compounds which can be reversibly oxidized or reduced four times, respectively, an unprecedented behavior for monomeric perylene derivatives. Spectroelectrochemical measurements show NIR absorptions up to 3000 nm for the mono-cation radical of (DPA)4-Per and a strong electronic coupling over the perylene bridge was observed indicative of fully delocalized Robin-Day Class III behavior. Both (DPA)4-Per and (Bmes2)4-Per derivatives possess unusually long intrinsic singlet lifetimes (τ 0), e.g., 94 ns for the former one. The compounds are emissive in solution, thin films, and the solid state, with apparent Stokes shifts that are exceptionally large for perylene derivatives. Transient absorption measurements on (DPA)4-Per reveal an additional excited state, with a long lifetime of 500 μs, which sensitizes singlet oxygen effectively.

PAVOOC: designing CRISPR sgRNAs using 3D protein structures and functional domain annotations

SUMMARY

Single-guide RNAs (sgRNAs) targeting the same gene can significantly vary in terms of efficacy and specificity. PAVOOC (Prediction And Visualization of On- and Off-targets for CRISPR) is a web-based CRISPR sgRNA design tool that employs state of the art machine learning models to prioritize most effective candidate sgRNAs. In contrast to other tools, it maps sgRNAs to functional domains and protein structures and visualizes cut sites on corresponding protein crystal structures. Furthermore, PAVOOC supports homology-directed repair template generation for genome editing experiments and the visualization of the mutated amino acids in 3D.

AVAILABILITY AND IMPLEMENTATION

PAVOOC is available under https://pavooc.me and accessible using modern browsers (Chrome/Chromium recommended). The source code is hosted at github.com/moritzschaefer/pavooc under the MIT License. The backend, including data processing steps, and the frontend are implemented in Python 3 and ReactJS, respectively. All components run in a simple Docker environment.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Abstract 3055: Genome-wide CRISPR/Cas9 screen for the identification of novel YAP1/TAZ modulators

Aberrant activation of the Hippo pathway effectors YAP1/TAZ promotes cell proliferation and tumorigenesis. To identify novel regulators of YAP1/TAZ as a possible means to treat cancer, we established a novel, FACS-based screening system monitoring YAP1/TAZ activity in MDA-MB-231 breast cancer cells. Using these cells, we performed a pooled genome-wide CRISPR/Cas9 knockout screen. We identified approximately 50 genes potentially activating YAP1/TAZ with functions in the Actin Cytoskeleton signaling, p53 signaling, cell polarity or ER stress, amongst others. Moreover, we identified about 30 potential targets which when knocked out induce activity of YAP1/TAZ. The list of hits included genes known to affect the YAP1/TAZ activity such as AJUBA, LATS2 and TEAD, demonstrating the validity of the screen. Functional validation of the novel potential YAP1/TAZ modulators will aid to the further understanding of YAP1/TAZ biology and may open the door to new therapeutic avenues for targeting YAP1/TAZ in cancer.

Citation Format: Jan Naujoks, Lisette Potze, Anna Anurin, Julia Kuehnlenz, Ralf Lesche, Atanas Kamburov, Ekaterina Nevedomskaya, Andreas Steffen, Martin Lange, Barbara Nicke. Genome-wide CRISPR/Cas9 screen for the identification of novel YAP1/TAZ modulators [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3055.

Computer-Aided Design of Luminescent Linear N-Heterocyclic Carbene Copper(I) Pyridine Complexes

Multireference configuration interaction methods including spin-orbit interactions have been employed to investigate the photophysical properties of various linear N-heterocyclic carbene (NHC) copper(I) pyridine complexes with the aim of designing performant thermally activated delayed fluorescence (TADF) emitters for use in organic-light-emitting diodes. Our theoretical results indicate that this structural motif is very favorable for generating excited triplet states with high quantum yield. The first excited singlet (S_MLCT) and corresponding triplet state (T_MLCT) are characterized by d_σ → π_Py metal-to-ligand charge-transfer (MLCT) excitations. Efficient intersystem crossing (ISC) and reverse ISC (rISC) between these states is mediated by a near-degenerate second triplet state (T_MLCT/LC) with large d_π → π_Py contributions. Spin-vibronic coupling is strong and is expected to play a major role in the (r)ISC processes. The calculations reveal, however, that the luminescence is effectively quenched by locally excited triplet states if the NHC ligand carries two diisopropylphenyl (DIPP) substituents. When DIPP is replaced with 1-adamantyl residues, this quenching process is suppressed and TADF in the UV spectral regime is predicted to proceed at a rate of about 1/μs. The introduction of +I substituents on the carbene and -M substituents on the pyridine allows tuning of the emission wavelength from the UV to the blue-green or green spectral region.

Near-Infrared Quadrupolar Chromophores Combining Three-Coordinate Boron-Based Superdonor and Superacceptor Units

Herein, two new quadrupolar acceptor-π-donor-π-acceptor (A-π-D-π-A) chromophores have been prepared featuring a strongly electron-donating diborene core and strongly electron-accepting dimesitylboryl (BMes₂ ) and bis(2,4,6-tris(trifluoromethyl)phenyl)boryl (B^F Mes₂ ) end groups. Analysis of the compounds by NMR spectroscopy, X-ray crystallography, cyclic voltammetry, and UV/Vis-NIR absorption and emission spectroscopy indicated that the compounds have extended conjugated π-systems spanning their B₄ C₈ cores. The combination of exceptionally potent π-donor (diborene) and π-acceptor (diarylboryl) groups, both based on trigonal boron, leads to very small HOMO-LUMO gaps, resulting in strong absorption in the near-IR region with maxima in THF at 840 and 1092 nm and very high extinction coefficients of ca. 120 000 m^-1  cm^-1 . Both molecules also display weak near-IR fluorescence with small Stokes shifts.

Photoactivated cell-killing involving a low molecular weight, donor-acceptor diphenylacetylene

Drug-like, donor–acceptor diphenylacetylenes cause efficient cell death upon photoactivation and hence have potential phototherapeutic applications.

Photoactivation of photosensitisers can be utilised to elicit the production of ROS, for potential therapeutic applications, including the destruction of diseased tissues and tumours. A novel class of photosensitiser, exemplified by DC324, has been designed possessing a modular, low molecular weight and ‘drug-like’ structure which is bioavailable and can be photoactivated by UV-A/405 nm or corresponding two-photon absorption of near-IR (800 nm) light, resulting in powerful cytotoxic activity, ostensibly through the production of ROS in a cellular environment. A variety of in vitro cellular assays confirmed ROS formation and in vivo cytotoxic activity was exemplified via irradiation and subsequent targeted destruction of specific areas of a zebrafish embryo.

Tandem fluorescence and Raman (fluoRaman) characterisation of a novel photosensitiser in colorectal cancer cell line SW480

A novel photosensitiser, DC473, designed with solvatochromatic fluorescence and distinct Raman signal, is detected with tandem fluoRaman in SW480 cells.

The development of new imaging tools, molecules and modalities is crucial to understanding biological processes and the localised cellular impact of bioactive compounds. A small molecule photosensitiser, DC473, has been designed to be both highly fluorescent and to exhibit a strong Raman signal in the cell-silent region of the Raman spectrum due to a diphenylacetylene structure. DC473 has been utilised to perform a range of novel tandem fluorescence and Raman (fluoRaman) imaging experiments, enabling a thorough examination of the compound's cellular localisation, exemplified in colorectal cancer cells (SW480). This multifunctional fluoRaman imaging modality revealed the presence of the compound in lipid droplets and only a weak signal in the cytosol, by both Raman and fluorescence imaging. In addition, Raman microscopy detected the compound in a cell compartment we labelled as the nucleolus, whereas fluorescence microscopy did not detect the fluoRaman probe due to solvatochromatic effects in a local polar environment. This last finding was only possible with the use of tandem confocal Raman and fluorescence methods. By following the approach detailed herein, incorporation of strong Raman functional groups into fluorophores can enable a plethora of fluoRaman experiments, shedding further light on potential drug compound's cellular behaviour and biological activity.

Carba-closo-dodecaboranylethynyl ligands facilitating luminescent reversed charge-transfer excited states in gold/silver complexes

Homo- and heterometallic gold(i) and silver(i) complexes with the carba-closo-dodecaboranylethynyl ligand were obtained and the participation of the boron cluster to the photophysical properties was proven.

Selective Photocatalytic C-F Borylation of Polyfluoroarenes by Rh/Ni Dual Catalysis Providing Valuable Fluorinated Arylboronate Esters

A highly selective and general photocatalytic C-F borylation protocol that employs a rhodium biphenyl complex as a triplet sensitizer and the nickel catalyst [Ni(IMes)₂] (IMes = 1,3-dimesitylimidazoline-2-ylidene) for the C-F bond activation and defluoroborylation process is reported. This tandem catalyst system operates with visible (blue, 400 nm) light and achieves borylation of a wide range of fluoroarenes with B₂pin₂ at room temperature in excellent yields and with high selectivity. Direct irradiation of the intermediary C-F bond oxidative addition product trans-[NiF(Ar^F)(IMes)₂] leads to very fast decomposition when B₂pin₂ is present. This destructive pathway can be bypassed by indirect excitation of the triplet states of the nickel(II) complex via the photoexcited rhodium biphenyl complex. Mechanistic studies suggest that the exceptionally long-lived triplet excited state of the Rh biphenyl complex used as the photosensitizer allows for efficient triplet energy transfer to trans-[NiF(Ar^F)(IMes)₂], which leads to dissociation of one of the NHC ligands. This contrasts with the majority of current photocatalytic transformations, which employ transition metals as excited state single electron transfer agents. We have previously reported that C(arene)-F bond activation with [Ni(IMes)₂] is facile at room temperature, but that the transmetalation step with B₂pin₂ is associated with a high energy barrier. Thus, this triplet energy transfer ultimately leads to a greatly enhanced rate constant for the transmetalation step and thus for the whole borylation process. While addition of a fluoride source such as CsF enhances the yield, it is not absolutely required. We attribute this yield-enhancing effect to (i) formation of an anionic adduct of B₂pin₂, i.e., FB₂pin₂^-, as an efficient, much more nucleophilic {Bpin^-} transfer reagent for the borylation/transmetalation process, and/or (ii) trapping of the Lewis acidic side product FBpin by formation of [F₂Bpin]^- to avoid the formation of a significant amount of NHC-FBpin and consequently decomposition of {Ni(NHC)₂} species in the reaction mixture.

Trends and regional variations in the administrative prevalence of attention-deficit/hyperactivity disorder among children and adolescents in Germany

There is a controversy regarding temporal trends in prevalence of attention-deficit/hyperactivity disorder (ADHD). Using nationwide claims data containing data for approximately six million statutory health insured children we aimed to examine a) trends of ADHD administrative prevalence during 2009-2016; b) regional variations in prevalence, and c) factors associated with an increased chance of ADHD diagnosis. The ICD-10 code 'F90-hyperkinetic disorder' was used to define an ADHD case. Global and Local Moran's I tests were used to examine the spatial autocorrelation and k-means-cluster analysis to examine the course of ADHD prevalence in administrative districts over years. Two-level logistic regression was applied to examine individual- and district-level factors associated with ADHD diagnosis. The administrative prevalence of ADHD was 4.33% (95% CI: 4.31-4.34%). We observed pronounced small-area differences on the district level with prevalences ranging between 1.6% and 9.7%. There was evidence of strong spatial autocorrelation (Global Moran's I: 0.46, p < 0.0001). The k-means-method identified six clusters of different size; all with a stagnating trend in the prevalence over the observation period of eight years. On the district level, a lower proportion of foreign citizens, and a higher density of paediatric psychiatrists and paediatricians were positively associated with ADHD with a more pronounced effect in urban districts.

Binding Kinetics Survey of the Drugged Kinome

Target residence time is emerging as an important optimization parameter in drug discovery, yet target and off-target engagement dynamics have not been clearly linked to the clinical performance of drugs. Here we developed high-throughput binding kinetics assays to characterize the interactions of 270 protein kinase inhibitors with 40 clinically relevant targets. Analysis of the results revealed that on-rates are better correlated with affinity than off-rates and that the fraction of slowly dissociating drug-target complexes increases from early/preclinical to late stage and FDA-approved compounds, suggesting distinct contributions by each parameter to clinical success. Combining binding parameters with PK/ADME properties, we illustrate in silico and in cells how kinetic selectivity could be exploited as an optimization strategy. Furthermore, using bio- and chemoinformatics we uncovered structural features influencing rate constants. Our results underscore the value of binding kinetics information in rational drug design and provide a resource for future studies on this subject.