Gut microbiota and clinical response to immune checkpoint inhibitor therapy in patients with advanced cancer.

BACKGROUND: There is currently no well-accepted consensus on the association between gut microbiota and the response to treatment of immune checkpoint inhibitors (ICIs) in patients with advanced cancer. METHODS: Fecal samples were collected before ICI treatment. Gut microbiota was analyzed using 16 S ribosomal RNA sequencing. We investigated the relationship between the α-diversity of fecal microbiota and patients' clinical outcomes. Microbiota profiles from patients and healthy controls were determined. Pre-treatment serum was examined by cytokine array. RESULTS: We analyzed 74 patients, including 42 with melanoma, 8 with kidney cancer, 13 with lung cancer, and 11 with other cancers. Combination therapy of anti-PD1 and anti-CTLA-4 was used in 14 patients, and monotherapy in the rest. Clinical benefit was observed in 35 (47.3 %) cases, including 2 complete responses, 16 partial responses, and 17 stable diseases according to RECIST criteria. No significant difference in α-diversity was found between the benefiter and non-benefiter groups. However, patients with α-diversity within the range of our healthy control had a significantly longer median overall survival (18.9 months), compared to the abnormal group (8.2 months) (p = 0.041, hazard ratio = 0.546) for all patients. The microbiota composition of the benefiters was similar to that of healthy individuals. Furthermore, specific bacteria, such as Prevotella copri and Faecalibacterium prausnitzii, were associated with a favorable outcome. We also observed that serum IL-18 before treatment was significantly lower in the benefiters, compared to non-benefiters. CONCLUSIONS: The α-diversity of gut microbiota is positively correlated with more prolonged overall survival in cancer patients following ICI therapy.

Using yeast surface display to engineer a soluble and crystallizable construct of hematopoietic progenitor kinase 1 (HPK1).

Hematopoietic progenitor kinase 1 (HPK1) is an intracellular kinase that plays an important role in modulating tumor immune response and thus is an attractive target for drug discovery. Crystallization of the wild-type HPK1 kinase domain has been hampered by poor expression in recombinant systems and poor solubility. In this study, yeast surface display was applied to a library of HPK1 kinase-domain variants in order to select variants with an improved expression level and solubility. The HPK1 variant with the most improved properties contained two mutations, crystallized readily in complex with several small-molecule inhibitors and provided valuable insight to guide structure-based drug design. This work exemplifies the benefit of yeast surface display towards engineering crystallizable proteins and thus enabling structure-based drug discovery.

Biologic-like In Vivo Efficacy with Small Molecule Inhibitors of TNFα Identified Using Scaffold Hopping and Structure-Based Drug Design Approaches.

Scaffold hopping and structure-based drug design were employed to identify substituted 4-aminoquinolines and 4-aminonaphthyridines as potent, small molecule inhibitors of tumor necrosis factor alpha (TNFα). Structure-activity relationships in both the quinoline and naphthyridine series leading to the identification of compound 42 with excellent potency and pharmacokinetic profile are discussed. X-ray co-crystal structure analysis and ultracentrifugation experiments clearly demonstrate that these inhibitors distort the TNFα trimer upon binding, leading to aberrant signaling when the trimer binds to TNF receptor 1 (TNFR1). Pharmacokinetic-pharmacodynamic activity of compound 42 in a TNF-induced IL-6 mouse model and in vivo activity in a collagen antibody-induced arthritis model, where it showed biologic-like in vivo efficacy, will be discussed.

Repeated centrifuging and washing concentrates bacterial samples in peritoneal dialysis for optimal culture: an original article.

BACKGROUND: Bacterial cultures allow the identification of infectious disease pathogens. However, obtaining the results of conventional culture methods is time-consuming, taking at least two days. A more efficient alternative is the use of concentrated bacterial samples to accelerate culture growth. Our study focuses on the development of a high-yield sample concentrating technique. RESULTS: A total of 71 paired samples were obtained from patients on peritoneal dialysis (PD). The peritoneal dialysates were repeat-centrifuged and then washed with saline, namely the centrifuging and washing method (C&W method). The concentrated samples were Gram-stained and inoculated into culture plates. The equivalent unprocessed dialysates were cultured as the reference method. The times until culture results for the two methods were compared. The reference method yielded no positive Gram stain results, but the C&W method immediately gave positive Gram stain results for 28 samples (p < 0.001). The culture-negative rate was lower in the C&W method (5/71) than in the reference method (13/71) (p = 0.044). The average time for bacterial identification achieved with the C&W method (22.0 h) was shorter compared to using the reference method (72.5 h) (p < 0.001). CONCLUSIONS: The C&W method successfully concentrated bacterial samples and superseded blood culture bottles for developing adequate bacterial cultures. The C&W method may decrease the culture report time, thus improving the treatment of infectious diseases.

Identification of N-Methyl Nicotinamide and N-Methyl Pyridazine-3-Carboxamide Pseudokinase Domain Ligands as Highly Selective Allosteric Inhibitors of Tyrosine Kinase 2 (TYK2).

As a member of the Janus (JAK) family of nonreceptor tyrosine kinases, TYK2 plays an important role in mediating the signaling of pro-inflammatory cytokines including IL-12, IL-23, and type 1 interferons. The nicotinamide 4, identified by a SPA-based high-throughput screen targeting the TYK2 pseudokinase domain, potently inhibits IL-23 and IFNα signaling in cellular assays. The described work details the optimization of this poorly selective hit (4) to potent and selective molecules such as 47 and 48. The discoveries described herein were critical to the eventual identification of the clinical TYK2 JH2 inhibitor (see following report in this issue). Compound 48 provided robust inhibition in a mouse IL-12-induced IFNγ pharmacodynamic model as well as efficacy in an IL-23 and IL-12-dependent mouse colitis model. These results demonstrate the ability of TYK2 JH2 domain binders to provide a highly selective alternative to conventional TYK2 orthosteric inhibitors.

Identification of Imidazo[1,2-b]pyridazine Derivatives as Potent, Selective, and Orally Active Tyk2 JH2 Inhibitors.

In sharp contrast to a previously reported series of 6-anilino imidazopyridazine based Tyk2 JH2 ligands, 6-((2-oxo-N1-substituted-1,2-dihydropyridin-3-yl)amino)imidazo[1,2-b]pyridazine analogs were found to display dramatically improved metabolic stability. The N1-substituent on 2-oxo-1,2-dihydropyridine ring can be a variety of alkyl, aryl, and heteroaryl groups, but among them, 2-pyridyl provided much enhanced Caco-2 permeability, attributed to its ability to form intramolecular hydrogen bonds. Further structure-activity relationship studies at the C3 position led to the identification of highly potent and selective Tyk2 JH2 inhibitor 6, which proved to be highly effective in inhibiting IFNγ production in a rat pharmacodynamics model and fully efficacious in a rat adjuvant arthritis model.

Discovery of furo[2,3-d][1,3]thiazinamines as beta amyloid cleaving enzyme-1 (BACE1) inhibitors.

This Letter describes the synthesis and structure-activity relationships of a series of furo[2,3-d][1,3]thiazinamine BACE1 inhibitors. The co-crystal structure of a representative thiazinamine 2e bound with the BACE1 active site displayed a binding mode driven by interactions with the catalytic aspartate dyad and engagement of the biaryl amide toward the S1 and S3 pockets. This work indicates that furo[2,3-d]thiazine can serve as a viable bioisostere of the known furo[3,4-d]thiazine.

Discovery of 6-Fluoro-5-(R)-(3-(S)-(8-fluoro-1-methyl-2,4-dioxo-1,2-dihydroquinazolin-3(4H)-yl)-2-methylphenyl)-2-(S)-(2-hydroxypropan-2-yl)-2,3,4,9-tetrahydro-1H-carbazole-8-carboxamide (BMS-986142): A Reversible Inhibitor of Bruton's Tyrosine Kinase (BTK) Conformationally Constrained by Two Locked Atropisomers.

Bruton's tyrosine kinase (BTK), a nonreceptor tyrosine kinase, is a member of the Tec family of kinases. BTK plays an essential role in B cell receptor (BCR)-mediated signaling as well as Fcγ receptor signaling in monocytes and Fcε receptor signaling in mast cells and basophils, all of which have been implicated in the pathophysiology of autoimmune disease. As a result, inhibition of BTK is anticipated to provide an effective strategy for the clinical treatment of autoimmune diseases such as lupus and rheumatoid arthritis. This article details the structure-activity relationships (SAR) leading to a novel series of highly potent and selective carbazole and tetrahydrocarbazole based, reversible inhibitors of BTK. Of particular interest is that two atropisomeric centers were rotationally locked to provide a single, stable atropisomer, resulting in enhanced potency and selectivity as well as a reduction in safety liabilities. With significantly enhanced potency and selectivity, excellent in vivo properties and efficacy, and a very desirable tolerability and safety profile, 14f (BMS-986142) was advanced into clinical studies.

Small Molecule Reversible Inhibitors of Bruton's Tyrosine Kinase (BTK): Structure-Activity Relationships Leading to the Identification of 7-(2-Hydroxypropan-2-yl)-4-[2-methyl-3-(4-oxo-3,4-dihydroquinazolin-3-yl)phenyl]-9H-carbazole-1-carboxamide (BMS-935177).

Bruton's tyrosine kinase (BTK) belongs to the TEC family of nonreceptor tyrosine kinases and plays a critical role in multiple cell types responsible for numerous autoimmune diseases. This article will detail the structure-activity relationships (SARs) leading to a novel second generation series of potent and selective reversible carbazole inhibitors of BTK. With an excellent pharmacokinetic profile as well as demonstrated in vivo activity and an acceptable safety profile, 7-(2-hydroxypropan-2-yl)-4-[2-methyl-3-(4-oxo-3,4-dihydroquinazolin-3-yl)phenyl]-9H-carbazole-1-carboxamide 6 (BMS-935177) was selected to advance into clinical development.

Discovery of S3-Truncated, C-6 Heteroaryl Substituted Aminothiazine ß-Site APP Cleaving Enzyme-1 (BACE1) Inhibitors.

Truncation of the S3 substituent of the biaryl aminothiazine 2, a potent BACE1 inhibitor, led to a low molecular weight aminothiazine 5 with moderate activity. Despite its moderate activity, compound 5 demonstrated significant brain Aß reduction in rodents. The metabolic instability of 5 was overcome by the replacement of the 6-dimethylisoxazole, a metabolic soft spot, with a pyrimidine ring. Thus, truncation of the S3 substituent represents a viable approach to the discovery of orally bioavailable, brain-penetrant BACE1 inhibitors.

Discovery and Preclinical Evaluation of BMS-711939, an Oxybenzylglycine Based PPARα Selective Agonist.

BMS-711939 (3) is a potent and selective peroxisome proliferator-activated receptor (PPAR) α agonist, with an EC50 of 4 nM for human PPARα and >1000-fold selectivity vs human PPARγ (EC50 = 4.5 µM) and PPARδ (EC50 > 100 µM) in PPAR-GAL4 transactivation assays. Compound 3 also demonstrated excellent in vivo efficacy and safety profiles in preclinical studies and thus was chosen for further preclinical evaluation. The synthesis, structure-activity relationship (SAR) studies, and in vivo pharmacology of 3 in preclinical animal models as well as its ADME profile are described.

Targeting the BACE1 Active Site Flap Leads to a Potent Inhibitor That Elicits Robust Brain Aß Reduction in Rodents.

By targeting the flap backbone of the BACE1 active site, we discovered 6-dimethylisoxazole-substituted biaryl aminothiazine 18 with 34-fold improved BACE1 inhibitory activity over the lead compound 1. The cocrystal structure of 18 bound to the active site indicated two hydrogen-bond interactions between the dimethylisoxazole and threonine 72 and glutamine 73 of the flap. Incorporation of the dimethylisoxazole substitution onto the related aminothiazine carboxamide series led to pyrazine-carboxamide 26 as a very potent BACE1 inhibitor (IC50 < 1 nM). This compound demonstrated robust brain Aß reduction in rat dose-response studies. Thus, compound 26 may be useful in testing the amyloid hypothesis of Alzheimer's disease.

Design and synthesis of carbazole carboxamides as promising inhibitors of Bruton's tyrosine kinase (BTK) and Janus kinase 2 (JAK2).

Four series of disubstituted carbazole-1-carboxamides were designed and synthesised as inhibitors of Bruton's tyrosine kinase (BTK). 4,7- and 4,6-disubstituted carbazole-1-carboxamides were potent and selective inhibitors of BTK, while 3,7- and 3,6-disubstituted carbazole-1-carboxamides were potent and selective inhibitors of Janus kinase 2 (JAK2).

Tyrosine Kinase 2-mediated Signal Transduction in T Lymphocytes Is Blocked by Pharmacological Stabilization of Its Pseudokinase Domain.

Inhibition of signal transduction downstream of the IL-23 receptor represents an intriguing approach to the treatment of autoimmunity. Using a chemogenomics approach marrying kinome-wide inhibitory profiles of a compound library with the cellular activity against an IL-23-stimulated transcriptional response in T lymphocytes, a class of inhibitors was identified that bind to and stabilize the pseudokinase domain of the Janus kinase tyrosine kinase 2 (Tyk2), resulting in blockade of receptor-mediated activation of the adjacent catalytic domain. These Tyk2 pseudokinase domain stabilizers were also shown to inhibit Tyk2-dependent signaling through the Type I interferon receptor but not Tyk2-independent signaling and transcriptional cellular assays, including stimulation through the receptors for IL-2 (JAK1- and JAK3-dependent) and thrombopoietin (JAK2-dependent), demonstrating the high functional selectivity of this approach. A crystal structure of the pseudokinase domain liganded with a representative example showed the compound bound to a site analogous to the ATP-binding site in catalytic kinases with features consistent with high ligand selectivity. The results support a model where the pseudokinase domain regulates activation of the catalytic domain by forming receptor-regulated inhibitory interactions. Tyk2 pseudokinase stabilizers, therefore, represent a novel approach to the design of potent and selective agents for the treatment of autoimmunity.

Longer dialysis times are associated with a lower chance of dementia among chronic hemodialysis patients.

Dementia is common in chronic hemodialysis (HD) patients and is associated with a higher mortality. Factors associated with dementia in HD patients are not clear. We investigated factors associated with early dementia in HD patients. Chronic HD patients of 27 hemodialysis centers were enrolled in 2013. Early dementia was identified using the AD8 assessment. Factors associated with early dementia were analyzed using logistic regression. A total of 1617 chronic HD patients including 820 males and 797 females, aged 63.3 ± 13 years, dialyzed for 4 (1.8-8.4) years were analyzed. Early dementia was identified in 414 (25.6%) of the patients. Longer HD times were associated with a lower chance of dementia (P = 0.032), with an adjusted odds ratio (OR) of 0.522 (95% confidence interval [CI]: 0.270-0.969) for every one more hour of HD. Patient's age (OR: 1.587, 95% CI: 1.406-1.791, P < 0.001), body mass index (OR: 0.958, 95% CI: 0.921-0.996, P = 0.031), cerebrovascular accident (OR: 1.480, 95% CI: 1.000-2.188), diabetes (OR: 1.894, 95% CI: 1.390-2.581, P < 0.001), and serum albumin (OR: 0.376, 95 % CI: 0.256-0.553, P < 0.001) were independently linked to early dementia. Short hemodialysis times are associated with early dementia in a chronic hemodialysis population with a quarter of patients having early dementia. Patients' age, nutrition status and comorbidity are independently linked to early dementia.

Purine derivatives as potent Bruton's tyrosine kinase (BTK) inhibitors for autoimmune diseases.

Investigation of various heterocyclic core isosteres of imidazopyrazines 1 & 2 yielded purine derivatives 3 & 8 as potent and selective BTK inhibitors. Subsequent SAR studies of the purine series led to the discovery of 20 as a leading compound. Compound 20 is very selective when screened against a panel of 400 kinases and is a potent inhibitor in cellular assays of human B cell function including B-Cell proliferation and CD86 cell surface expression and exhibited in vivo efficacy in a mouse PCA model. Its X-ray co-crystal structure with BTK shows that the high selectivity is gained from filling a BTK specific lipophilic pocket. However, physical and ADME properties leading to low oral exposure hindered further development.

The structure of human tau-tubulin kinase 1 both in the apo form and in complex with an inhibitor.

Tau-tubulin kinase 1 (TTBK1) is a dual-specificity (serine/threonine and tyrosine) kinase belonging to the casein kinase 1 superfamily. TTBK1 is a neuron-specific kinase that regulates tau phosphorylation. Hyperphosphorylation of tau is implicated in the pathogenesis of Alzheimer's disease. Two kinase-domain constructs of TTBK1 were expressed in a baculovirus-infected insect-cell system and purified. The purified TTBK1 kinase-domain proteins were crystallized using the hanging-drop vapor-diffusion method. X-ray diffraction data were collected and the structure of TTBK1 was determined by molecular replacement both as an apo structure and in complex with a kinase inhibitor.

X-ray crystal structure of bone marrow kinase in the x chromosome: a Tec family kinase.

Bone marrow kinase in the X chromosome, a member of the Tec family of tyrosine kinases, plays a role in both monocyte/macrophage trafficking as well as cytokine secretion. Although the structures of Tec family kinases Bruton's tyrosine kinase and IL-2-inducible T-cell kinase are known, the crystal structures of other Tec family kinases have remained elusive. We report the X-ray crystal structures of bone marrow kinase in the X chromosome in complex with dasatinib at 2.4 Å resolution and PP2 at 1.9 Å resolution. The bone marrow kinase in the X chromosome structures reveal a typical kinase protein fold; with well-ordered protein conformation that includes an open/extended activation loop and a stabilized DFG-motif rendering the kinase in an inactive conformation. Dasatinib and PP2 bind to bone marrow kinase in the X chromosome in the ATP binding pocket and display similar binding modes to that observed in other Tec and Src protein kinases. The bone marrow kinase in the X chromosome structures identify conformational elements of the DFG-motif that could potentially be utilized to design potent and/or selective bone marrow kinase in the X chromosome inhibitors.

Nutritional status of vegetarians on maintenance haemodialysis.

AIM: Vegetarian diets have long been thought of as beneficial to health. However, vegetarian diets are often low in protein, which is contradictory to the high protein diet guideline for uraemia patients. The purpose of the study was to investigate the impact of a vegetarian diet on the nutritional status of haemodialysis (HD) patients. METHODS: Patients on chronic HD for over 6 months were included in the study. The normalized protein catabolic rate (nPCR) was used to reflect daily protein intake. Biochemical markers of nutrition, anthropometric parameters, subjective global assessment (SGA) and functional activity of daily living were assessed to evaluate the nutritional status of vegetarians on chronic HD. RESULTS: Nineteen out of 318 HD patients were vegetarians. The nPCR was lower in the vegetarian group (1.20 ± 0.24 vs 1.10 ± 0.29 g/kg per day, non-Veg vs Veg, P < 0.05). The serum albumin and prealbumin were similar in vegetarian and non-vegetarian HD patients. The body mass index (BMI) and mid-arm muscular circumference (MAMC) were lower in vegetarian patients (P < 0.05). The haematocrit of vegetarians can be maintained at a level similar to that of non-vegetarian patients but erythropoietin doses needed were higher in vegetarian patients (P < 0.05). The muscle strength evaluated by the hand-grip test, SGA and activities of daily living were similar in vegetarians and non-vegetarians. CONCLUSION: The present study revealed that HD patients on vegetarian diets might have a smaller BMI, but SGA and function of daily activities were similar to those of the non-vegetarians. The haematocrit of vegetarians can be maintained with a higher erythropoietin dose.