Small Pocket Research Articles

Abstract B37: PLX-4107, a selective IKZF2 degrader, reprograms suppressive regulatory T cells and demonstrates anti-tumor activity

Abstract Immune checkpoint therapy has demonstrated durable clinical responses in multiple solid tumor types. Reduced clinical response to checkpoint therapy has been linked to the presence of potent immunosuppressive regulatory T cells (Tregs) within the tumor microenvironment that contribute to tumor immune evasion. The transcription factor Helios (IKZF2) is a marker of highly suppressive Tregs and is required to maintain a stable, suppressive Treg cell phenotype in the inflammatory tumor microenvironment. Depletion of IKZF2 in Tregs results in both loss of suppressive activity and conversion of Tregs into effector-like T cells, leading to anti-tumor immunity. Targeted protein degradation using the endogenous Ubiquitin Proteasome System (UPS) has enabled targeting undruggable proteins, such as IKZF2, that have no known small molecule binding pocket. We have designed small molecules that promote a novel interaction between IKZF2 with the E3 ubiquitin ligase substrate receptor, Cereblon, leading to proximity induced protein degradation. PLX-4107 is a novel molecular glue that is a highly selective, potent, and rapid degrader of IKZF2 via the redirection of the E3 substrate receptor, Cereblon. Degradation of IKZF2 by PLX-4107 is blocked in the presence of proteasome and neddylation inhibitors as well as a Cereblon knock-out cell line, confirming that degradation is mediated by the UPS and specifically through the involvement of Cereblon. Proteome-wide analysis demonstrated that PLX-4107 selectively depletes IKZF2 protein levels without degrading other known Cereblon neo-substrates. In vitro, PLX-4107 mediated degradation of IKZF2 resulted in conversion of suppressive Tregs into CD4+ effector-like T cells, coupled with an increased production of the effector cytokines IL2 and IFNg. Oral administration of PLX-4107 to cynomolgus monkeys demonstrated sustained pharmacodynamic response, persistent depletion of IKZF2, and reprogramming of Tregs, consistent with the catalytic mechanism of protein degradation. In vivo, T cell expansion studies showed that administration of PLX-4107 decreased both Treg CD25 expression and proliferation, along with increased activation of CD8+ T effector cells. PLX-4107 was evaluated in in vivo xenograft efficacy studies and demonstrated dose dependent single agent anti-tumor activity that was dependent on the presence of T cells. In addition, co-administration of PLX-4107 and anti-PD-1 antibody Pembrolizumab resulted in tumor growth inhibition and significant combination benefit. PLX-4107 is a novel molecular glue that selectively degrades the undruggable transcription factor, IKZF2. PLX-4107 mediated IKZF2 degradation results in conversion of Tregs to an effector-like T cell phenotype, single agent antitumor activity and the ability to enhance the efficacy of immune checkpoint therapy in vivo. Citation Format: Peggy A Thompson, Pengyu Yang, Linette Yang, Susan Song, Yujun Huang, Xiaoming Li, Alejandro Dearie, Stephen Chien, Mary E Spalding, Gabrielle Blanco, Elizabeth Daniele, Julia Toth, Aleksandar Jamborcic, Gregory Parker, Simon Bailey. PLX-4107, a selective IKZF2 degrader, reprograms suppressive regulatory T cells and demonstrates anti-tumor activity [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy; 2022 Oct 21-24; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(12 Suppl):Abstract nr B37.

Small globes and pocket heat stress meters for WBGT and PHS evaluations. A critical analysis under controlled conditions

This paper is aimed at quantifying the effects of the well-known criticalities related to the use of small globes in the assessment of extreme hot thermal environments. Based on the experimental measurements carried out through a special apparatus able to reproduce a black enclosure under controlled conditions, the analysis has been focused on both screening (WBGT) and rational (PHS) assessment methods. Obtained results showed the underestimation of the WBGT values within 1 °C using small globes for measuring the WBGT index according to the Standard ISO 7243 and no relevant errors occur also in the presence of high radiative loads. These errors can be even eliminated if specific correction coefficients for the heat transfer by convection are used. On the other hand, pocket WBGT meters based upon small globes and psychrometric (shielded) sensors – instead of the wet wick – are affected by an unacceptable underestimation (by more than 10 °C) of the WBGT that is particularly enhanced at low air velocity and high radiative loads. Finally, the systematic underestimation of the mean radiant temperature measured through small globes can lead the allowable exposure times predicted by the PHS model to be underestimated by more than 5 h when a 38 mm table-tennis ball is used.

Auricular Reconstruction: Modifications to Classification and Surgical Approach

PURPOSE: One of the primary treatments for microtia is two-stage autogenous auricular reconstruction. The first stage involves a costal cartilage framework inset, and the second stage elevates the framework using fascial flaps, wedge cartilage grafts, and skin grafts. We present modifications to the conceptual classifications and surgical approach to auricular reconstruction with a focus on small concha-type microtia. MODIFICATION OF TECHNIQUE: 1) Microtia is classified into four sub-categories: lobule type, conchal type, small concha-type, and anotia. Planning the surgical approach begins with accurately identifying the category. Small concha-type microtia is often overlooked or thought to be a simple indentation in the conchal bowl region. The small concha is often a cavity, instead of an indentation, and located anteriorly to the normal conchal bowl. 2) The proper location of the ear can be determined by constructing an ‘auricular rectangle,’ a term coined by the senior author that utilizes multiple topographic references of the unaffected side in unilateral microtia: top of upper helix, caudal end of lobule, Frankfurt Horizontal line, shape of hairline, and face mask. If the face is asymmetrical like in severe hemifacial microsomia, identification of the auricular rectangle is more challenging and perfect symmetry is less attainable. Identifying the proper location of the ear is crucial to gauge if the vestige is in a surgically-usable location. 3) Surgical technique has evolved from a V- to W-shaped incision along the posterior surface of the auricle to maximize the skin surface area and create the deep concha. The W-shape also creates a superior advancement of the vestige. If the vestige is located at the same height as the unaffected side, the flap is more U-shaped. Additionally, the W-shape can be made asymmetric to create the desired 10-15 degree posterior inclination of the ear framework. 4) The hallmark of small concha-type microtia is that the small concha is not located in the correct anatomic location, so the skin flap elevated off the indent is too anteriorly positioned to be used for the tragus as much of the literature suggests. The small concha skin pocket should instead be excised. 5) After vestigial cartilage is removed and the cartilage framework is inserted around the subcutaneous pedicle of W-flap, the anterior lobule flap and transposed W-flap are closed. Temporary suction is applied to adhere the skin envelope to the framework. The final location and posterior inclination of the ear is determined, which reveals the areas of redundant skin, typically the anterior helix. Although conventional teachings do not include skin trimming, the senior author finds that horizontal wound closure has been successful in providing uninterrupted blood supply while preventing ischemia after years of training under Satoru Nagata and years of independent practice. CONCLUSION: These modifications advance our understanding of microtia classifications and how the surgical approach can be tailored to best utilize each component of the vestige. The functional outcomes of auricular reconstruction are especially important in light of the coronavirus disease 2019 (COVID-19) pandemic where the ability to wear masks relies on external ear function.

Highly Specific and Sensitive Naked-Eye Fluoride Ion Recognition via Unzipping a Helical Poly(phenylacetylene)

Fluoride anion (F–) recognition has attracted much attention in recent years due to its significant role in biological, medical, environmental, and industrial processes. Although many artificial receptors show high sensitivity toward F–, they still lack the specificity for such an anion. It still remains a great challenge to endow the receptors with high specificity and sensitivity toward F– at the same time. Herein, a contracted cis-cisoid poly(phenylacetylene) derivative (Poly-1) has been synthesized, whose preferred-handed helix can be stabilized by intramolecular hydrogen bonding networks among neighboring pendant amides. The average layer distance between its side chains of 3.88 Å can provide a small pocket, which is suitable to accommodate the smallest anion F– with high basicity, but excludes other anions. When the first F– binds to the pendant amides via intermolecular hydrogen bonding, the main chain conformational transition into a stretched cis-transoid nonpreferred-handed helix is triggered, which facilitates the subsequent F– binding. Such an unzipping effect gives rise to an ultralow detection limit of 2.85 × 10–8 M (0.54 ppb) for F–. Meanwhile, the solution color change from colorless to yellow can be observed because of the conjugated cis-transoid conformation of Poly-1. As a result, a highly specific and sensitive naked-eye recognition toward F– is realized. This work lays a solid foundation for the development of smart materials on the basis of stimuli-responsive cascade processes.

Structural basis for the substrate specificity of an S-formylglutathione hydrolase derived from Variovorax sp. PAMC 28711

S-Formylglutathione hydrolase was originally known to catalyze the hydrolysis of S-formylglutathione to formate and glutathione. However, this enzyme has a broader esterase activity toward substrates containing thioester and ester bonds. In a previous study, we identified a new S-formylglutathione hydrolase (VaSFGH) gene in the Antarctic bacterium Variovorax sp. PAMC 28711, and recombinant VaSFGH protein was purified and characterized. Previous enzyme activity assays showed that VaSFGH has high activity, especially toward short-chain p-nitrophenyl esters (C2–C4). In this study, we determined the crystal structure of substrate-free VaSFGH at a resolution of 2.38 Å. In addition, p-nitrophenyl ester-bound VaSFGH structure models were generated by molecular docking simulations to obtain structural evidence of its substrate specificity. Comparative structural analysis of the apo-form and p-nitrophenyl ester-bound VaSFGH model structures revealed that large substrates could not bind inside the hydrophobic substrate-binding pocket because of the intrinsically static and relatively small substrate-binding pocket size of VaSFGH. This study provides useful information for further protein engineering of SFGHs for industrial use.

Spontaneosus Pneumothorax

Background: Pneumothorax is a medical emergency which is defined as an abnormal condition where there is air in the pleural cavity which physiologically contains only a small amount of fluid. Pneumothorax can arise spontaneously or as a result of trauma. Method: The method used in this study is a literature review. The literature study conducted by the author is by searching various written sources, whether in the form of books, archives, magazines, articles and journals, or documents that are relevant to the problem being studied. Discussion: Pneumothorax is classified as primary spontaneous if it occurs in the absence of basic lung disease or thoracic trauma. Pneumothorax is classified as secondary spontaneous if it is caused by basic lung disease. The etiology of primary spontaneous pneumothorax is pleural bleb and bulla. A bleb (air pocket) or bulla is a small air-filled pocket that forms between the lung and pleural tissues. The risk factors associated with pneumothorax are smoking and body thinness. Conclusion: The initial management of spontaneous pneumothorax includes emergency management. Furthermore, management can be divided into conservative and invasive management

Implications of the Essential Role of Small Molecule Ligand Binding Pockets in Protein-Protein Interactions.

Protein-protein interactions (PPIs) and protein-metabolite interactions play a key role in many biochemical processes, yet they are often viewed as being independent. However, the fact that small molecule drugs have been successful in inhibiting PPIs suggests a deeper relationship between protein pockets that bind small molecules and PPIs. We demonstrate that 2/3 of PPI interfaces, including antibody-epitope interfaces, contain at least one significant small molecule ligand binding pocket. In a representative library of 50 distinct protein-protein interactions involving hundreds of mutations, >75% of hot spot residues overlap with small molecule ligand binding pockets. Hence, ligand binding pockets play an essential role in PPIs. In representative cases, evolutionary unrelated monomers that are involved in different multimeric interactions yet share the same pocket are predicted to bind the same metabolites/drugs; these results are confirmed by examples in the PDB. Thus, the binding of a metabolite can shift the equilibrium between monomers and multimers. This implicit coupling of PPI equilibria, termed "metabolic entanglement", was successfully employed to suggest novel functional relationships among protein multimers that do not directly interact. Thus, the current work provides an approach to unify metabolomics and protein interactomics.

Complex magnetic phase diagram with a small phase pocket in a three-dimensional frustrated magnet CuInCr4S8

Frustrated magnets with a strong spin-lattice coupling can show rich magnetic phases and the associated fascinating phenomena. A promising platform is the breathing pyrochlore magnet ${\mathrm{CuInCr}}_{4}{\mathrm{S}}_{8}$ with localized $S=3/2\phantom{\rule{4pt}{0ex}}{\mathrm{Cr}}^{3+}$ ions, which is proposed to be effectively viewed as an $S=6$ Heisenberg antiferromagnet on the face-centered-cubic lattice. Here we unveil that ${\mathrm{CuInCr}}_{4}{\mathrm{S}}_{8}$ exhibits a complex magnetic phase diagram with a small phase pocket ($A$ phase) by means of magnetization, magnetostriction, magnetocapacitance, and magnetocaloric-effect measurements in pulsed high magnetic fields of up to 60 T. Remarkably, the appearance of $A$ phase is accompanied by anomalous magnetostrictive and magnetocapacitive responses, suggesting the emergence of helimagnetism in contrast to the neighboring commensurate magnetic phases. Besides, the high-entropy nature is confirmed in the high-temperature side of $A$ phase. These features are potentially related to a thermal fluctuation-driven multiple-$q$ state caused by the magnetic frustration, which has been theoretically predicted but yet experimentally undiscovered in insulating magnets.

KRAS-Mutant Non-Small-Cell Lung Cancer: From Past Efforts to Future Challenges.

KRAS is the most frequently mutated oncogene identified in human cancers. Despite the numerous efforts to develop effective specific inhibitors against KRAS, this molecule has remained “undruggable” for decades. The development of direct KRAS inhibitors, such as sotorasib, the first FDA-approved drug targeting KRAS G12C, or adagrasib, was made possible with the discovery of a small pocket in the binding switch II region of KRAS G12C. However, a new challenge is represented by the necessity to overcome resistance mechanisms to KRAS inhibitors. Another area to be explored is the potential role of co-mutations in the selection of the treatment strategy, particularly in the setting of immune checkpoint inhibitors. The aim of this review was to analyze the state-of-the-art of KRAS mutations in non-small-cell lung cancer by describing the biological structure of KRAS and exploring the clinical relevance of KRAS as a prognostic and predictive biomarker. We reviewed the different treatment approaches, focusing on the novel therapeutic strategies for the treatment of KRAS-mutant lung cancers.

Enantioselective Synthesis of Pharmaceutically Relevant Bulky Arylbutylamines Using Engineered Transaminases

AbstractATAs engineered for having an enlarged small binding pocket were applied for the synthesis of enantiomerically pure (R)‐benzo[1,3]dioxol‐5‐yl‐butylamine, a chiral component of human leukocyte elastase inhibitor DMP 777 (L‐694,458). Kinetic resolution of the racemic amine was performed by using the L59A variant of the (S)‐selective ATA from Chromobacterium violaceum (Cv‐ATA), providing the residual (R)‐enantiomer in excellent yield and >99% ee. At moderate enzyme loading and absence of co‐solvent, high volumetric productivity of 0.22 mol L−1 h−1 (42.5 g L−1 h−1) was achieved. Complementarily, the (S)‐enantiomer was generated via kinetic resolution using the (R)‐selective ATA‐117‐Rd11 from Arthrobacter sp. with acetone as the amino acceptor. In an alternative approach, we employed ATA‐117‐Rd11 for the asymmetric amination of the prochiral ketone precursor, which at 86% conversion gave the (R)‐benzo[1,3]dioxol‐5‐yl‐butylamine with excellent >99% ee. We further evaluated the utility of Cv‐ATA L59A for the asymmetric synthesis of pharmaceutically relevant (S)‐1‐phenylbutan‐1‐amine, a chiral component of the deubiquitinase inhibitor degrasyn (WP1130). The enzyme showed good tolerance to high concentrations of isopropylamine, producing (S)‐1‐phenylbutan‐1‐amine in enantiomerically pure form (>99% ee).magnified image

Luminogenic HiBiT Peptide-Based NanoBRET Ligand Binding Assays for Melatonin Receptors.

The two human melatonin receptors MT1 and MT2, which belong to the G protein-coupled receptor (GPCR) family, are important drug targets with approved indications for circadian rhythm- and sleep-related disorders and major depression. Currently, most of the pharmacological studies were performed using [3H]melatonin and 2-[125I]iodomelatonin (2-[125I]-MLT) radioligands. Recently, NanoLuc-based bioluminescence resonance energy transfer (NanoBRET) monitoring competitive binding between fluorescent tracers and unmodified test compounds has emerged as a sensitive, nonradioactive alternative for quantifying GPCR ligand engagement on the surface of living cells in equilibrium and real time. However, developing such assays for the two melatonin receptors depends on the availability of fluorescent tracers, which has been challenging predominantly owing to their narrow ligand entry channel and small ligand binding pocket. Here, we generated a set of melatonergic fluorescent tracers and used NanoBRET to evaluate their engagement with MT1 and MT2 receptors that are genetically fused to an N-terminal luminogenic HiBiT-peptide. We identified several nonselective and subtype-selective tracers. Among the selective tracers, PBI-8238 exhibited high nanomolar affinity to MT1, and PBI-8192 exhibited low nanomolar affinity to MT2. The pharmacological profiles of both tracers were in good agreement with those obtained with the current standard 2-[125I]-MLT radioligand. Molecular docking and mutagenesis studies suggested the binding mode of PBI-8192 in MT2 and its selectivity over MT1. In conclusion, we describe the development of the first nonradioactive, real-time binding assays for melatonin receptors expressed at the cell surface of living cells that are likely to accelerate drug discovery for melatonin receptors.

A systematic exploration of boceprevir-based main protease inhibitors as SARS-CoV-2 antivirals

Boceprevir is an HCV NSP3 inhibitor that was explored as a repurposed drug for COVID-19. It inhibits the SARS-CoV-2 main protease (MPro) and contains an α-ketoamide warhead, a P1 β-cyclobutylalanyl moiety, a P2 dimethylcyclopropylproline, a P3 tert-butylglycine, and a P4 N-terminal tert-butylcarbamide. By introducing modifications at all four positions, we synthesized 20 boceprevir-based MPro inhibitors including PF-07321332 and characterized their MPro inhibition potency in test tubes (in vitro) and 293T cells (in cellulo). Crystal structures of MPro bound with 10 inhibitors and cytotoxicity and antiviral potency of 4 inhibitors were characterized as well. Replacing the P1 site with a β-(S-2-oxopyrrolidin-3-yl)-alanyl (Opal) residue and the warhead with an aldehyde leads to high in vitro potency. The original moieties at P2, P3 and the P4 N-terminal cap positions in boceprevir are better than other tested chemical moieties for high in vitro potency. In crystal structures, all inhibitors form a covalent adduct with the MPro active site cysteine. The P1 Opal residue, P2 dimethylcyclopropylproline and P4 N-terminal tert-butylcarbamide make strong hydrophobic interactions with MPro, explaining high in vitro potency of inhibitors that contain these moieties. A unique observation was made with an inhibitor that contains a P4 N-terminal isovaleramide. In its MPro complex structure, the P4 N-terminal isovaleramide is tucked deep in a small pocket of MPro that originally recognizes a P4 alanine side chain in a substrate. Although all inhibitors show high in vitro potency, they have drastically different in cellulo potency to inhibit ectopically expressed MPro in human 293T cells. In general, inhibitors with a P4 N-terminal carbamide or amide have low in cellulo potency. This trend is reversed when the P4 N-terminal cap is changed to a carbamate. The installation of a P3 O-tert-butyl-threonine improves in cellulo potency. Three molecules that contain a P4 N-terminal carbamate were advanced to cytotoxicity tests on 293T cells and antiviral potency tests on three SARS-CoV-2 variants. They all have relatively low cytotoxicity and high antiviral potency with EC50 values around 1 μM. A control compound with a nitrile warhead and a P4 N-terminal amide has undetectable antiviral potency. Based on all observations, we conclude that a P4 N-terminal carbamate in a boceprevir derivative is key for high antiviral potency against SARS-CoV-2.

Abstract 1111: Identification of selective IKZF2 degraders that reprogram suppressive regulatory T cells in solid tumors

Abstract Targeted protein degradation (TPD) using the endogenous Ubiquitin Proteasome System (UPS) is a rapidly growing drug discovery strategy to eliminate pathogenic proteins. Molecular glues are small molecules that promote a novel interaction between a protein of interest with an E3 ubiquitin ligase leading to proximity induced protein degradation. This has enabled targeting undruggable proteins, such as the zinc-finger transcription factor Helios (IKZF2), that have no known small molecule binding pocket. Despite recent clinical breakthroughs in checkpoint blockade in treating solid tumors, suppression of the antitumor immune response in the tumor microenvironment (TME) is a major obstacle to tumor regression. Regulatory T cells (Tregs) in the TME are potent immunosuppressive cells that promote progression of cancer. IKZF2 has been shown to be a marker of highly suppressive Treg cells and is critical for maintaining the anergic and suppressive phenotype in the highly inflammatory tumor microenvironment. Genetic depletion of IKZF2 in Treg cells results in both loss of suppressive activity and conversion of Tregs into T effector cells, leading to enhanced anti-tumor immunity. Collectively, these findings support that an IKZF2-specific degrader could be beneficial in enhancing the efficacy of current immunotherapies. Here we report our efforts leading to the development of a series of potent and selective IKZF2 degraders for the treatment of cancer. Our lead compound, PLX-4107, is a novel molecular glue that was optimized to be a highly selective, deep, and rapid IKZF2 degrader via the redirection of the E3 substrate receptor, cereblon. Proteome-wide analysis demonstrated that PLX-4107 depletes IKZF2 protein levels without degrading other known cereblon neo-substrates. PLX-4107 mediated degradation of IKZF2 resulted in conversion of highly suppressive Tregs into T effector cells, coupled with an increased expression of the effector cytokines IL2 and IFNγ. Oral administration of PLX-4107 to cynomolgus monkeys caused rapid, complete, and prolonged degradation of IKZF2 in Tregs, indicative of the catalytic nature of degraders where sustained pharmacodynamic response is observed well beyond plasma drug exposure levels. These preliminary data provide a strong rationale for developing small molecule therapeutics that target the undruggable IKZF2 transcription factor with the potential to enhance the efficacy of immune checkpoint therapy. Citation Format: Peggy A. Thompson, Pengyu Yang, Xiaoming Li, Stephen Chien, Mary E. Spalding, Alejandro Dearie, Elizabeth Daniele, Linette Yang, E Adam Kallel, Aleksandar Jamborcic, Julia Toth, Gregory Parker, Simon Bailey. Identification of selective IKZF2 degraders that reprogram suppressive regulatory T cells in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1111.

Abstract 2478: Development of a novel HIF2a PET tracer: From proof of concept to a clinical trial

Abstract Normally induced by hypoxia, hypoxia-inducible factor 2 alpha (HIF2a) is arguably the most important driver of kidney cancer. HIF2a is constitutively activated following von Hippel-Lindau (VHL) gene inactivation, which is the signature event of the most common type of kidney cancer, clear cell renal cell carcinoma (ccRCC). HIF2a functions as a heterodimeric transcription factor in partnership with the constitutive HIF1b subunit and regulates a program of gene expression that promotes cell proliferation, stemness, and angiogenesis. While as a transcription factor HIF2a had escaped drug targeting, structural studies revealed an unusual cavity, which became the foundation for the development of small molecule inhibitors such as PT2385 (a first-in-class drug), or the related PT2399 tool compound and the recently FDA-approved PT2977 (also called belzutifan). PT drugs bind a small pocket in the PAS-B domain of HIF2a inducing a conformational change that triggers dissociation from its obligatory partner HIF1b. PT drugs are highly specific - they do not bind the close paralog HIF1a and do not induce changes in gene expression in cells devoid of HIF2a. Using an extensive library of patient-derived xenografts (PDXs), we previously showed that PT drugs have activity against 50% of ccRCCs implanted in mice, and similar observations were made in the clinic. Perhaps unsurprisingly, sensitive tumors showed higher HIF2a levels. Here, we leverage the specificity of PT2385 to develop a HIF2a tracer for positron emission tomography (PET). By substituting a native fluorine atom for 18F, we generated [18F]PT2385. [18F]PT2385 was able to discriminate HIF2a-expressing ccRCCs from tumors that did not express HIF2a in mice simultaneously implanted with both. These data set the foundation for an investigator new drug (IND) approval from the FDA, and a clinical trial that is currently accruing patients (NCT04989959). [18F]PT2385 PET may have applications in identifying kidney cancer patients most likely to respond to HIF2a-targeted therapies, the identification of other tumors relying on HIF2a, and beyond oncology. Reporting on a hypoxia sensor, a HIF2a radiotracer may be a useful ischemia probe. In summary, we report the development of a novel radiotracer with extensive potential applications currently being evaluated in humans. Citation Format: Sashi Debnath, Christina Stevens, Olivia Brandenburg, Justin Sovich, Paulina Gonzalez, Qian (Janie) Qin, Sydney Haldeman, Vanina Toffessi Tcheuyap, Alana Christie, Pawan Thapa, Ning Zhou, Aditi Mulgaonkar, Guiyang Hao, Jeffrey Miyata, Deyssy Carrillo, Jeffrey Cadeddu, Payal Kapur, Jon Anderson, Ivan Pedrosa, Marianna Dakanali, Orhan Oz, Xiankai Sun, James Brugarolas. Development of a novel HIF2a PET tracer: From proof of concept to a clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2478.

A New and Easier Approach to Preserflo MicroShunt Implantation.

PRESERFLO™ MicroShunt is a new minimally invasive glaucoma surgical (MIGS) device, implanted with an ab externo approach, which drains the aqueous humor to the subconjunctival space. It has been designed as a safer and less invasive approach for treating medically uncontrolled primary open-angle glaucoma (POAG) patients. The classic way of MicroShunt implantation involves different key steps, which includes creating a small scleral pocket with a 1mm blade; passing a 25-gauge (25G) needle through the scleral pocket into the anterior chamber (AC); and subsequently flushing the stent with a 23-gauge (23G) thin-wall cannula. However, sliding the needle into the scleral pocket can create false passages, thus making the device’s threading more difficult. The purpose of the current paper is to propose a simplified implantation approach. Our method proposes to make the scleral tunnel by using directly the 25G needle and, at the limbus, this 25G needle is used to slightly depress the sclera and enter into the AC. The MicroShunt is subsequently assembled on a 23G cannula mounted on a 1mL syringe. The syringe can then be used to flush the device. Outflow can thus be confirmed immediately by seeing drops of aqueous humor leaking from the external opening of the stent. This new approach may have different potential advantages, such as better control of the site of entry, avoids wrong passages, reduces or eliminates the risk of aqueous humor sideway flow, facilitates a parallel path to the iris plane, and it is faster.

Anisotropic giant magnetoresistanceand de Hass–van Alphen oscillations in layered topological semimetal crystals

Here, we report an anisotropic giant magnetoresistance (GMR) effect and de Hass–van Alphen (dHvA) oscillation phenomena in nominal TaNiTe5 single crystals. TaNiTe5 exhibits the GMR effect with the maximum value of ∼3 × 103% at T = 1.7 K and B = 31 T, with no sign of saturation. The two-band model fitting of Hall resistivity indicates that the anomalous GMR effect was derived from the coexistence of electron and hole carriers. When the external magnetic field is applied to the electron–hole resonance, the GMR effect is enhanced. The dHvA oscillation data at multiple frequencies reveal the topological characteristics of high carrier mobility, low carrier effective mass, and a small Fermi surface pocket with a nontrivial Berry phase. Our work provides a new platform for the study of topological semimetals with significant anisotropic GMR effect.

Topological pseudogap in highly polarizable layered systems with 2D hole-like dispersion

Pseudogap in hole-doped cuprate superconductors is acknowledged as a possible key to understanding their ground normal state, however, existing pseudogap models have essential inconsistencies with experiments. In our approach pseudogap emerges due to impact of autolocalized carriers on stationary states of delocalized ones and topology of the 2D hole-like dispersion. Autolocalized carriers create potential which transforms Bloch quasiparticles into distributed wave packets (DWPs) with different momentums in areas with different potential. Topology of hole-like constant energy curves in 2D-conducting cuprates forbids DWPs with average momentums near antinode. Manifestation of permitted DWPs in ARPES spectra demonstrates all known pseudogap features including midpoint shift, giant broadening and Fermi momentum misalignment. Calculated doping dependence of the pseudogap width and onset temperature agrees with experiments. The obtained ground normal state of the hole-doped cuprates, in which all the doped holes are autolocalized until high doping is reached and near-antinodal electron DWPs are absent, explains Fermi surface reconstruction from small electron pocket to large hole-like Fermi surface observed in quantum oscillation measurements. Our results open a possibility of creating systems with artificial pseudogap and switchable density of states on the base of highly polarizable layered structures with 2D conductivity and hole-like dispersion.

Pocket parks for human-centered urban climate change resilience: Microclimate field tests and multi-domain comfort analysis through portable sensing techniques and citizens’ science

Dense urban areas are subject to dynamic and urgent challenges, exacerbated by anthropogenic forcing. Urban Heat Island and heatwaves pose a threat to citizens’ comfort, due to extreme microclimate conditions. In this panorama, urban parks represent effective strategies towards more livable and comfortable urban areas. In particular, small pocket parks could aid in the mitigation of such challenges in every neighborhood. Indeed, they are in close proximity to citizens, allowing large population groups to benefit from the advantage of living green areas. Therefore, this paper assesses for the first time microclimate conditions and personal multi-domain perception imputable to pocket parks, by means of human-centered experimental analyses, coupling objective and subjective assessment. Wearable monitoring-systems are employed for the assessment of granular-microclimate variables mapping, and questionnaire-surveys are collected in the pocket parks and their surroundings, for comparison purposes. Results show that, while microclimate mitigation is not extremely significant as expected (−0.5 °C air temperature, +5–10% relative humidity inside the park), perceived comfort in pocket parks is higher than on the streets, shifting from “neutral” on the close by streets to “good/very good” in the park. Therefore, a better design for microclimate mitigation of pocket parks is needed, especially taking into account the potential air stagnation, while acknowledging their fundamental societal role.

A cryptic phosphate-binding pocket on the SPFH domain of human stomatin that regulates a novel fibril-like self-assembly.

Human stomatin (hSTOM) is a component of the membrane skeleton of erythrocytes that maintains the membrane's shape and stiffness through interconnecting spectrin and actin. hSTOM is a member of the protein family that possesses a single stomatin/prohibitin/flotillin/HflK (SPFH) domain at the center of the molecule. Although SPFH domain proteins are widely distributed from archaea to mammals, the detailed function of the domain remains unclear. In this study, we first determined the solution structure of the SPFH domain of hSTOM (hSTOM(SPFH)) via NMR. The solution structure of hSTOM(SPFH) is essentially identical to the already reported crystal structure of the STOM SPFH domain (mSTOM(SPFH)) of mice, except for the existence of a small hydrophilic pocket on the surface. We identified this pocket as a phosphate-binding site by comparing its NMR spectra with and without phosphate ions. Meanwhile, during the conventional process of protein NMR analysis, we eventually discovered that hSTOM(SPFH) formed a unique solid material after lyophilization. This lyophilized hSTOM(SPFH) sample was moderately slowly dissolved in a physiological buffer. Interestingly, it was resistant to dissolution against the phosphate buffer. We then found that the lyophilized hSTOM(SPFH) formed a fibril-like assembly under electron microscopy. Finally, we succeeded in reproducing this fibril-like assembly of hSTOM(SPFH) using a centrifugal ultrafiltration device, thus demonstrating that the increased protein concentration may promote self-assembly of hSTOM(SPFH) into fibril forms. Our observations may help understand the molecular function of the SPFH domain and its involvement in protein oligomerization as a component of the membrane skeleton. (245 words).

Establishing the mutational effect on the binding susceptibility of AMG510 to KRAS switch II binding pocket: Computational insights

After decades of leaving patients with limited treatment options due to the ‘undruggability’ of Kirsten rat sarcoma, the kernel was finally cracked with the discovery of Sotorasib. This novel drug binds to a small pocket on the switch II of Kirsten rat sarcoma by exploiting the mutation that occurs at codon 12 wherein glycine is replaced by cysteine. However, this pocket is not only prone to cysteine mutation but other mutations occur as well including at codon 13. These mutations have been reported to drive cancer in the lungs, colorectal and in solid tumors with varying degree of expressions. Sotorasib is therefore only effective in a small group of patients especially those expressing cysteine at codon 12, reminding drug hunters of the unfinished work. This study employs computational techniques to understand the susceptibility of the mutated binding pocket to the binding of Sotorasib. It was revealed that the binding affinity of Sotorasib to other mutations aside Cysteine was significantly affected via the total free binding energies presented by the mutated complexes. Furthermore, the quantum of energy contributed by the mutated residues except cysteine was significantly reduced suggesting the binding of Sotorasib is enhanced in only cysteine mutated Kirsten rat sarcoma. Residual interaction network showed Sotorasib in complex with the cysteine mutated protein presented the highest degree centrality, shortest path betweenness, shortest path centrality and shortest path degree indicating Sotorasib controls more information flow within the cysteine mutated protein than in other mutations. Insight unraveled here will provide aid in the development of pan Kirsten rat sarcoma inhibitory small molecules.