Discovery of potent small-molecule inhibitors of lipoprotein(a) formation.

Lipoprotein(a) (Lp(a)), an independent, causal cardiovascular risk factor, is a lipoprotein particle that is formed by the interaction of a low-density lipoprotein (LDL) particle and apolipoprotein(a) (apo(a))1,2. Apo(a) first binds to lysine residues of apolipoprotein B-100 (apoB-100) on LDL through the Kringle IV (KIV) 7 and 8 domains, before a disulfide bond forms between apo(a) and apoB-100 to create Lp(a) (refs. 3-7). Here we show that the first step of Lp(a) formation can be inhibited through small-molecule interactions with apo(a) KIV7-8. We identify compounds that bind to apo(a) KIV7-8, and, through chemical optimization and further application of multivalency, we create compounds with subnanomolar potency that inhibit the formation of Lp(a). Oral doses of prototype compounds and a potent, multivalent disruptor, LY3473329 (muvalaplin), reduced the levels of Lp(a) in transgenic mice and in cynomolgus monkeys. Although multivalent molecules bind to the Kringle domains of rat plasminogen and reduce plasmin activity, species-selective differences in plasminogen sequences suggest that inhibitor molecules will reduce the levels of Lp(a), but not those of plasminogen, in humans. These data support the clinical development of LY3473329-which is already in phase 2 studies-as a potent and specific orally administered agent for reducing the levels of Lp(a).

Small molecule inhibitors targeting regulatory T cells for cancer treatment.

Regulatory T cells (Tregs) are important controllers of the immune system homeostasis by preventing disproportionate immune responses. In the context of cancer, Tregs contribute to tumor development by suppressing other immune cells in the tumor microenvironment (TME). Infiltration of Tregs in the TME has been associated with poor prognosis in cancer patients. Thus, understanding the mechanisms underlying Treg recruitment and suppressive functions is essential for developing cancer immunotherapies to boost antitumor immune responses. While antibody-based strategies targeting Tregs have shown promise, small molecule inhibitors offer distinct advantages, including oral bioavailability and the ability to penetrate the TME and target intracellular proteins. Here, we provide an overview of small molecule inhibitors that have demonstrated efficacy in modulating Tregs activity in cancer and highlight the need for phenotypic assays to characterize therapeutic compounds.

Using normal mode analysis on protein structural models. How far can we go on our predictions?

Normal mode analysis (NMA) is a fast and inexpensive approach that is largely used to gain insight into functional protein motions, and more recently to create conformations for further computational studies. However, when the protein structure is unknown, the use of computational models is necessary. Here, we analyze the capacity of NMA in internal coordinate space to predict protein motion, its intrinsic flexibility, and atomic displacements, using protein models instead of native structures, and the possibility to use it for model refinement. Our results show that NMA is quite insensitive to modeling errors, but that calculations are strictly reliable only for very accurate models. Our study also suggests that internal NMA is a more suitable tool for the improvement of structural models, and for integrating them with experimental data or in other computational techniques, such as protein docking or more refined molecular dynamics simulations.

Structural insights into the allosteric site of Arabidopsis NADP-malic enzyme 2: role of the second sphere residues in the regulatory signal transmission.

KEY MESSAGE: NADP-ME2 from Arabidopsis thaliana exhibits a distinctive and complex regulation by fumarate, acting as an activator or an inhibitor according to substrate and effector concentrations. In this work, we used molecular modeling approach and site-directed mutagenesis to characterized the NADP-ME2 structural determinants necessary for allosteric regulation providing new insights for enzyme optimization. Structure-function studies contribute to deciphering how small modifications in the primary structure could introduce desirable characteristics into enzymes without affecting its overall functioning. Malic enzymes (ME) are ubiquitous and responsible for a wide variety of functions. The availability of a high number of ME crystal structures from different species facilitates comparisons between sequence and structure. Specifically, the structural determinants necessary for fumarate allosteric regulation of ME has been of particular interest. NADP-ME2 from Arabidopsis thaliana exhibits a distinctive and complex regulation by fumarate, acting as an activator or an inhibitor according to substrate and effector concentrations. However, the 3D structure for this enzyme is not yet reported. In this work, we characterized the NADP-ME2 allosteric site by structural modeling, molecular docking, normal mode analysis and mutagenesis. The regulatory site model and its docking analysis suggested that other C4 acids including malate, NADP-ME2 substrate, could also fit into fumarate's pocket. Besides, a non-conserved cluster of hydrophobic residues in the second sphere of the allosteric site was identified. The substitution of one of those residues, L62, by a less flexible residue as tryptophan, resulted in a complete loss of fumarate activation and a reduction of substrate affinities for the active site. In addition, normal mode analysis indicated that conformational changes leading to the activation could originate in the region surrounding L62, extending through the allosteric site till the active site. Finally, the results in this work contribute to the understanding of structural determinants necessary for allosteric regulation providing new insights for enzyme optimization.

A Novel Nociceptin Receptor Antagonist LY2940094 Inhibits Excessive Feeding Behavior in Rodents: A Possible Mechanism for the Treatment of Binge Eating Disorder.

Nociceptin/orphanin FQ (N/OFQ), a 17 amino acid peptide, is the endogenous ligand of the ORL1/nociceptin-opioid-peptide (NOP) receptor. N/OFQ appears to regulate a variety of physiologic functions including stimulating feeding behavior. Recently, a new class of thienospiro-piperidine-based NOP antagonists was described. One of these molecules, LY2940094 has been identified as a potent and selective NOP antagonist that exhibited activity in the central nervous system. Herein, we examined the effects of LY2940094 on feeding in a variety of behavioral models. Fasting-induced feeding was inhibited by LY2940094 in mice, an effect that was absent in NOP receptor knockout mice. Moreover, NOP receptor knockout mice exhibited a baseline phenotype of reduced fasting-induced feeding, relative to wild-type littermate controls. In lean rats, LY2940094 inhibited the overconsumption of a palatable high-energy diet, reducing caloric intake to control chow levels. In dietary-induced obese rats, LY2940094 inhibited feeding and body weight regain induced by a 30% daily caloric restriction. Last, in dietary-induced obese mice, LY2940094 decreased 24-hour intake of a high-energy diet made freely available. These are the first data demonstrating that a systemically administered NOP receptor antagonist can reduce feeding behavior and body weight in rodents. Moreover, the hypophagic effect of LY2940094 is NOP receptor dependent and not due to off-target or aversive effects. Thus, LY2940094 may be useful in treating disorders of appetitive behavior such as binge eating disorder, food choice, and overeating, which lead to obesity and its associated medical complications and morbidity.

A Novel, Orally Bioavailable Nociceptin Receptor Antagonist, LY2940094, Reduces Ethanol Self-Administration and Ethanol Seeking in Animal Models.

BACKGROUND: The nociceptin/orphanin-FQ (or opioid receptor-like [ORL1]) receptor (NOP) is localized in the mesolimbic reward pathway and has been suggested to play a role in feeding, mood, stress, and addiction. Since its deorphanization in 1995, there has been a clear dichotomy in the literature regarding whether an agonist or antagonist would provide therapeutic benefit. Specifically, the literature reports indicate that NOP receptor antagonists produce efficacy in animal models of hyperphagia and antidepressant-like activity, whereas NOP agonists produce anxiolytic-like effects and dampen reward/addiction behaviors including ethanol consumption. METHODS: We characterize here the potent, orally bioavailable NOP antagonist, LY2940094, in rodent models of ethanol consumption, including ethanol self-administration, progressive ratio operant self-administration, stress-induced reinstatement of ethanol seeking, and in vivo microdialysis in the nucleus accumbens. RESULTS: LY2940094 dose dependently reduced homecage ethanol self-administration in Indiana alcohol-preferring (P) and Marchigian Sardinian alcohol-preferring (msP) rats, without affecting food/water intake or locomotor activity. Reduced ethanol intake in P rats did not show significant tolerance over 4 days of subchronic dosing. LY2940094 attenuated progressive ratio operant responding and break points for ethanol in P rats. Moreover, stress-induced reinstatement of ethanol seeking in msP rats was completely blocked by LY2940094. Furthermore, LY2940094 blocked ethanol-stimulated dopamine release in response to ethanol challenge (1.1 g/kg, intraperitoneally). CONCLUSIONS: Our findings demonstrate for the first time that blockade of NOP receptors attenuates ethanol self-administration and ethanol-motivated behaviors, stress-induced ethanol seeking, and ethanol-induced stimulation of brain reward pathways in lines of rats that exhibit excessive ethanol consumption. Results suggest that LY2940094 may have potential therapeutic utility in treating alcohol addiction.

Design, Synthesis and Evaluation of New Fluoroamodiaquine Analogues.

Malaria is one of the most important tropical diseases; the use of amodiaquine as a current chemotherapy in the treatment of malaria has shown some problems such as hepatotoxicity and agranulocytosis. In this work we present the rational design, synthesis, and biological evaluation (antimalarial activity, cytotoxicity and genotoxicity) of four new fluoroamodiaquine analogues. The results showed significant correlation between MolDock score and IC50 values. The molecules 7b and c were the most active of the planned compounds, with lower IC50 against Plasmodium falciparum W2 strain (0.9 and 0.8 µM, respectively) and an excellent cytotoxicity profile. The present study revealed no mutagenicity or genotoxicity for the analogues. Confirming our docking results, the molecular dynamics showed that compound 7b remains stably bound to the heme group by means of π-stacking interactions between quinoline and the porphyrin ring. Based on these findings, this study may prove to be an efficient approach for the rational design of hemozoin inhibiting compounds to treat malaria.

Genetic and structural analysis of polyomavirus BK T-antigens reveal a higher density of mutations at inter-domain and hexamerization regions, regardless the status of infection.

Polyomavirus BK (BKPyV) T-antigens (large and small tumor antigens, or Lt-ag and st-ag, respectively), control key aspects of viral replication and are able to regulate cell cycle, promoting cell proliferation. However, the structural effects of genetic mutations on T-antigens are poorly investigated. In this study, 214 sequences of T-antigens from individuals with different BKPyV infections (16 renal transplant with nephropathy; 78 asymptomatic renal transplant; 24 hematopoietic stem cell transplant with hemorrhagic cystitis; 96 healthy non-transplant), were analyzed from the genetic and structural standpoints. We found a high concentration of non-synonymous mutations at inter-domains and hexamerization regions of both proteins, being five of them under positive selection in the Lt-ag but none in the st-ag. The in silico analysis indicated that two mutations, located at positions 164 in the st-ag and 592 in the Lt-ag, would significantly affect the interaction with PP2A and p53 cell targets, respectively, although they were not associated to a specific clinical status. No mutations were detected on the J-domains or at the ATPase motif. In sum, the profile of the mutations found seem not to be associated to increased morbidity. This is the first work to analyze structural modifications on T-antigens in different BKPyV infections, and managed to map conserved and variable regions of the T-antigens, which will be helpful for the study of new antiviral drugs.

Genetic and structural analysis of Merkel cell polyomavirus large T antigen from diverse biological samples.

Merkel cell polyomavirus (MCPyV) large T antigen (LT-ag) is frequently found truncated in Merkel cell carcinomas (MCC) and it is considered a major tumor-specific signature. Nonetheless, the biological role of LT-ag nontruncated mutations is largely unknown. In this study, MCPyV LT-ag second exon from 11 non-MCC oral samples and NCBI sequences derived from different anatomical sites were studied from the genetic and structural standpoint. As expected, the LT-ag mutation profile was influenced by the geographical origin of the sample, although nonsynonymous mutations were more frequent in lesional tissues. Our in silico study suggests that the mutations found would not significantly affect protein functions, regardless of sample category. This work presents a thorough investigation of the structural and functional properties of LT-ag nontruncated mutations in MCPyV. Our results sustain the geographical influence of the MCPyV genetic profile, but do not discard genetic tissue specificities. Further investigation involving other genetic segments in healthy and lesional tissues are necessary to improve our knowledge on MCPyV pathogenesis.

Predictors and efficacy of surgical treatment for consecutive exotropia.

PURPOSE: To study the surgical outcomes of consecutive exotropia and predictive factors, and to compare the medial rectus (MR) advancement, lateral rectus (LR) recession, or a combination of both procedures. METHODS: A retrospective study of patients diagnosed with consecutive exotropia that were operated on (2000-2020) were included. The convergence was classified from 0 to +++, with good: ++/+++ and poor: 0/+. A good outcome was considered when the final horizontal deviation was < 10 prism diopters (pd). Follow-up since the surgery and the number of reoperations were registered. RESULTS: A total of 88 cases were analyzed, mean age: 33.98 ± 17.68 years (57.95%: women). The near and distance horizontal deviation mean (±SD) was 34.3 pd (±16.45) and 34.36 pd (±16.33), respectively. MR advancement was performed in 36.36%, LR recession in 27.27%, and a combination of both in 36.36%. Surgery was unilateral in 65.91% (bilateral in 34.09%). A good outcome was obtained in 69.32% and reoperations in 11.36%. The insufficiency convergence was associated with a bad outcome. The near horizontal deviation (P = .006), the vertical deviation (VD) association (P = .036) and the combination of both MR advancement and LR recession (P = .017) were predictors of a bad result. The mean follow-up was 56.5 months ± 57.65. CONCLUSION: A long-term good surgical result was obtained in most patients. The greatest near deviation, the VD association, and the combination of MR advancement and the LR recession were predictive factors for bad results.

Diterpenes isolated from Canistrocarpus cervicornis with virucidal activity against HIV-1: an in silico evaluation.

HIV is a public health problem, which makes necessary the development of new drugs. Natural products are known for their anti-HIV potential and a good strategy to suggest its mechanism of action is using in silico tools. Herein, diterpenes 1-3 had the binding mode evaluated in the HIV-1 glycoprotein; and properties ADMET in silico performed. In molecular docking important interactions between the hydrophobic cavity, and 1 and 2 were observed. In the molecular dynamics, 1 remained stable covering the entire hydrophobic cavity and performed hydrogen bond during all simulation. ADMET evaluation showed good properties for the diterpenes. Based on these findings, it was possible to suggest the potential from natural products as entry inhibitor and HIV-1 treatment.

PLCγ1/PKCθ Downstream Signaling Controls Cutaneous T-Cell Lymphoma Development and Progression.

Developing mechanistic rationales can improve the clinical management of cutaneous T-cell lymphomas. There is considerable genetic and biological evidence of a malignant network of signaling mechanisms, highly influenced by deregulated TCR/PLCγ1 activity, controlling the biology of these lesions. In addition, activated signal transducer and activator of transcription 3 is associated with clinical progression, although the alterations responsible for this have not been fully elucidated. Here, we studied PLCγ1-dependent mechanisms that can mediate STAT3 activation and control tumor growth and progression. Downstream of PLCγ1, the pharmacological inhibition and genetic knockdown of protein kinase C theta (PKCθ) inhibited signal transducer and activator of transcription 3 activation, impaired proliferation, and promoted apoptosis in cutaneous T-cell lymphoma cells. A PKCθ-dependent transcriptome in mycosis fungoides/Sézary syndrome cells revealed potential effector genes controlling cytokine signaling, TP53, and actin cytoskeleton dynamics. Consistently, an in vivo chicken embryo model xenografted with mycosis fungoides cells showed that PKCθ blockage abrogates tumor growth and spread to distant organs. Finally, the expression of a number of PKCθ target genes found in mycosis fungoides cells significantly correlated with that of PRKCQ (PKCθ) in 81 human mycosis fungoides samples. In summary, PKCθ can play a central role in the activation of malignant cutaneous T-cell lymphoma mechanisms via multiple routes, including, but not restricted to, STAT3. These mechanisms may, in turn, serve as targets for specific therapies.

Activity and safety of topical pimecrolimus in patients with early stage mycosis fungoides (PimTo-MF): a single-arm, multicentre, phase 2 trial.

BACKGROUND: The calcineurin pathway is often activated in mycosis fungoides. We aimed to assess the activity and safety of topical pimecrolimus, a calcineurin inhibitor, in patients with early mycosis fungoides. METHODS: PimTo-MF was a single-arm, multicentre, phase 2 trial done at six medical centres in Spain. Patients (aged ≥18 years) had histologically confirmed early mycosis fungoides (stages IA-IIA) and an Eastern Cooperative Oncology Group performance status of 0-1. Key exclusion criteria included the use of concurrent treatments for mycosis fungoides, including sunbathing, topical or systemic corticosteroids, and other calcineurin inhibitors. Patients applied topical pimecrolimus 1% cream on their skin lesions twice daily for 16 weeks (1 g per 2% of body surface), with subsequent follow-up of 12 months. Dosage modifications were not allowed. To evaluate adherence to the treatment, patients were instructed to return all empty tubes to the hospital (as per drug accountability protocols). The primary endpoint was the overall response ratein the intention-to-treat population. PimTo-MF is registered with EudraCT, 2014-001377-14, and is complete. FINDINGS: Between March 1, 2015, and Sept 30, 2016, 39 patients were enrolled. All patients were assessable, with a median age of 51·5 years (IQR 45-62), and the population was predominantly male (24 male [62%], 15 female [38%]). Median follow-up after baseline was 5·7 years (IQR 5·7-6·2). 22 (56%) of 39 patients had an overall response (one complete response, 21 partial responses). Responses were observed across IA (14 [54%] of 26 patients) and IB (eight [73%] of 11 patients) clinical stages, but not IIA. Topical pimecrolimus was well tolerated and no patient required a dose reduction or discontinued treatment because of unacceptable drug-related toxicity. No patients were lost to follow-up or discontinued treatment. 13 (33%) of 39 patients reported adverse events; transitory mild burning or pruritus (grade 1) was the most common, seen in eight (21%) patients. In three (8%) of these patients, the burning or pruritus was considered related to treatment. No grade 4 or 5 adverse events were observed. INTERPRETATION: Pimecrolimus 1% cream seems active and safe in patients with early stage mycosis fungoides. Our findings should be taken with caution until long-term follow-up data are obtained that confirm the safety of this treatment. Further controlled clinical trials are warranted to confirm these results. FUNDING: Instituto de Salud Carlos III and the European Regional Development Fund. TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.

Mycosis Fungoides and Sézary Syndrome: An Integrative Review of the Pathophysiology, Molecular Drivers, and Targeted Therapy.

Primary cutaneous T-cell lymphomas (CTCLs) constitute a heterogeneous group of diseases that affect the skin. Mycosis fungoides (MF) and Sézary syndrome (SS) account for the majority of these lesions and have recently been the focus of extensive translational research. This review describes and discusses the main pathobiological manifestations of MF/SS, the molecular and clinical features currently used for diagnosis and staging, and the different therapies already approved or under development. Furthermore, we highlight and discuss the main findings illuminating key molecular mechanisms that can act as drivers for the development and progression of MF/SS. These seem to make up an orchestrated constellation of genomic and environmental alterations generated around deregulated T-cell receptor (TCR)/phospholipase C, gamma 1, (PLCG1) and Janus kinase/ signal transducer and activator of transcription (JAK/STAT) activities that do indeed provide us with novel opportunities for diagnosis and therapy.

Phase Separation and Disorder-to-Order Transition of Human Brain Expressed X-Linked 3 (hBEX3) in the Presence of Small Fragments of tRNA.

Brain Expressed X-linked (BEX) protein family consists of five members in humans and is highly expressed during neuronal development. They are known to participate in cell cycle and in signaling pathways involved in neurodegeneration and cancer. BEX3 possess a conserved leucine-rich nuclear export signal and experimental data confirmed BEX3 nucleocytoplasmic shuttling. Previous data revealed that mouse BEX3 auto-associates in an oligomer rich in intrinsic disorder. In this work, we show that human BEX3 (hBEX3) has well-defined three-dimensional structure in the presence of small fragments of tRNA (tRFs). Conversely, the nucleic acids-free purified hBEX3 presented disordered structure. Small-angle X-ray scattering data revealed that in the presence of tRFs, hBEX3 adopts compact globular fold, which is very distinct from the elongated high-order oligomer formed by the pure protein. Furthermore, microscopy showed that hBEX3 undergoes condensation in micron-sized protein-rich droplets in vitro. In the presence of tRFs, biomolecular condensates were smaller and in higher number, showing acridine orange green fluorescence emission, which corroborated with the presence of base-paired nucleic acids. Additionally, we found that over time hBEX3 transits from liquid condensates to aggregates that are reversible upon temperature increment and dissolved by 1,6-hexanediol. hBEX3 assemblies display different morphology in the presence of the tRFs that seems to protect from amyloid formation. Collectively, our findings support a role for tRFs in hBEX3 disorder-to-order transition and modulation of phase transitions. Moreover, hBEX3 aggregation-prone features and the specificity in interaction with tRNA fragments advocate paramount importance toward understanding BEX family involvement in neurodevelopment and cell death.

Identification of tipifarnib sensitivity biomarkers in T-cell acute lymphoblastic leukemia and T-cell lymphoma.

Patients diagnosed with T-cell leukemias and T-cell lymphomas (TCLs) still have a poor prognosis and an inadequate response to current therapies, highlighting the need for targeted treatments. We have analyzed the potential therapeutic value of the farnesyltransferase inhibitor, tipifarnib, in 25 TCL cell lines through the identification of genomic and/or immunohistochemical markers of tipifarnib sensitivity. More than half of the cell lines (60%) were considered to be sensitive. Tipifarnib reduced cell viability in these T-cell leukemia and TCL cell lines, induced apoptosis and modified the cell cycle. A mutational study showed TP53, NOTCH1 and DNMT3 to be mutated in 84.6%, 69.2% and 30.0% of sensitive cell lines, and in 62.5%, 0% and 0% of resistant cell lines, respectively. An immunohistochemistry study showed that p-ERK and RelB were associated as potential biomarkers of tipifarnib sensitivity and resistance, respectively. Data from RNA-seq show that tipifarnib at IC50 after 72 h downregulated a great variety of pathways, including those controlling cell cycle, metabolism, and ribosomal and mitochondrial activity. This study establishes tipifarnib as a potential therapeutic option in T-cell leukemia and TCL. The mutational state of NOTCH1, p-ERK and RelB could serve as potential biomarkers of tipifarnib sensitivity and resistance.

The year's new drugs & biologics - 2008.

This annual article presents new drugs and biologics that were launched or approved for the first time during the previous year. In 2008, 31 new medicines-this figure includes both drugs and biologics for therapeutic use as well as new diagnostic agents-reached their first markets. Line extensions (new indications, new formulations and new combinations of previously marketed products) accounted for more than one-third of the new medicines launched in 2008. In addition to providing an overview of all drugs and biologics launched or approved for the first time ever in the previous year, this article will also review in further depth the first-in-class drugs launched for the first time last year, providing a better understanding of their novel mechanisms of action; an analysis of the discovery and development periods for the year's new products; and a comprehensive overview of drug repositioning as a strategy for extending the life spans of medicines. We also provide a brief glimpse at selected drugs and biologics which could reach their first markets in the foreseeable future.

[Dehabituation in drug-addicts and chronic pain]. / Deshabituación en drogodependientes y dolor crónico.

In a sample of patients under treatment for dependence disorder, the fear-avoidance model of pain was used as a theoretical framework to investigate differences between patients who developed chronic pain after the abstinence period and those who did not. In line with the model, a set of variables involved in the chronification process were considered: anxiety sensitivity, experiential avoidance, fear of pain, coping styles, anxiety, depression, and quality of life. Differences in clinical and dependence-related variables were analyzed: diagnosis of dual pathology, polyconsumption, prescribed medication, and methadone dose. A group of chronic pain patients (n=63) and a pain-free group (n=58) were compared. MANOVA and chi2 results indicated that the chronic pain patients had been diagnosed with dual pathology significantly more often than the pain-free group, they presented higher polyconsumption, and had been prescribed higher doses of methadone and more medications. The chronic pain group had poorer quality of life and significantly higher scores in anxiety sensitivity, experiential avoidance, and depression. No significant differences were found in coping strategies, fear of pain and anxiety.