Home Based Cardiac Rehabilitation Participation Among Patients With Heart Failure.

INTRODUCTION: Patients with Heart Failure (HF) have significant morbidity and mortality. Home Based Cardiac Rehabilitation (HBCR) is a form of Cardiac Rehabilitation (CR) which has been proven beneficial for the patients with cardiovascular disease; However, cardiovascular outcomes in patients with HF who was referred to HBCR is not known. METHODS: A retrospective study of 188 patients with HF (HFrEF or heart failure with reduced ejection fraction and HFpEF or heart failure with preserved ejection fraction) referred to HBCR at Veterans Affairs Medical Center (VAMC) from November 2017 to March 2020. We used the outcomes of patients with HF who attended HBCR and compared with the outcomes of patients who did not attend HBCR (Non-HBCR) from 3 months after starting HBCR till 12 months. Primary outcome was composite of all-cause mortality and cardiovascular hospitalizations. Secondary outcomes were all-cause mortality, cardiovascular hospitalizations and all-cause hospitalization, separately. We used cox proportional methods to calculate hazard ratios (HR) and 95% CI. We adjusted for imbalanced characteristics at baseline: age, smoking, PCI and CABG status. In subgroup analysis, we compared HFrEF and HFpEF patients who have completed HBCR and compared differences of their outcomes (weight, blood pressure, cholesterol, LDL, HDL, triglycerides, HbA1C, 6 Minutes walking test, duke score and PHQ-9) pre- and post-HBCR. RESULTS: Mean age of the patients was 72 year and 98% were male. Out of 188 patients total, 11 patients were excluded for the main analysis as their outcomes occurred within first 90 days of HBCR enrollment, 105/177 (59%) patients attended HBCR while 72/177 (41%) patients did not attend HBCR and 93/105 (89%) patients have completed HBCR. The primary outcome occurred in 14 patients (13.3%) in the HBCR group and 19 patients (26.4%) in the Non-HBCR group (adjusted HR=0.32, CI 0.15-0.68). There was no difference in cardiovascular hospitalization among two groups, however patients in HBCR group have lower all-cause hospitalizations and all-cause death, separately. After HBCR completion, all outcomes (weight, blood pressure, cholesterol, LDL, HDL, triglycerides, HbA1C, 6 Minutes walking test, duke score and PHQ-9) have improved in both HFrEF and HFpEF group. CONCLUSION: Patients with HF who have completed HBCR have a lower risk of all-cause mortality, all cause hospitalization separately and lower risk of combined all-cause mortality and cardiovascular hospitalization. Patients with HFrEF and HFpEF have equal degree of improvement after completing HBCR when compared with each other. HBCR is an ideal opportunity for patients with HF who cannot attend center-based CR and also for patients with HFpEF since CR is not approved for those patients.

COVID-19 Vaccine Hesitancy and Confidence in the Philippines and Malaysia: A Cross-sectional Study of Sociodemographic Factors and Information-Seeking

With the emergence of the highly transmissible Omicron variant, large-scale vaccination coverage is crucial to the national and global pandemic response, especially in populous Southeast Asian countries such as the Philippines and Malaysia. Little is known, however, about predictors of COVID-19 vaccine hesitancy and vaccine confidence among unvaccinated individuals in these regions. An internet-based cross-sectional survey was conducted from May 2021 to September 2021. Data from a total of 2558 participants from the Philippines (N = 1002) and Malaysia (N = 1556) were analysed. Results showed that Filipino (vs. Malaysian) participants indicated higher prevalence of COVID-19 vaccine hesitancy (56.6 vs. 22.9%, p = 0.001). However, there were no significant differences in ratings of vaccine confidence between Filipino (45.9%) and Malaysian (49.2%) participants (p = 0.105). Predictors associated with greater vaccine hesitancy included females (p = 0.029) and rural dwellers (p = 0.015) among Filipino participants, whereas females (p = 0.004), 25-34 year olds (p = 0.027), Christians (p < 0.001), and social media use (p < 0.001) were associated with hesitancy among Malaysian participants. Predictors associated with lower confidence included females (p = 0.026) and information seeking (p < 0.001) among Filipino participants, whereas predictors associated with lower confidence among Malaysian participants included residing in a rural community (p = 0.004), Christians (p < 0.001), online information seeking (p < 0.001), and determining relevance of online information (p = 0.013). Efforts to improve uptake of COVID-19 vaccination must be centred upon targeting specific communities using local authorities and for the masses through social media. Efforts should focus on determining effective interventions to decrease vaccination hesitancy and increase the uptake of COVID-19 vaccination, particularly in light of the Dengvaxia crisis in the Philippines.

Implications of ligand-receptor binding kinetics on GLP-1R signalling.

G protein-coupled receptors (GPCRs) are the largest class of membrane proteins and in recent years there has been a growing appreciation of the importance in understanding temporal aspects of GPCR behaviour, including the kinetics of ligand binding and downstream receptor mediated signalling. Class B1 GPCRs are activated by peptide agonists and are validated therapeutic targets for numerous diseases. However, the kinetics of ligand binding and how this is linked to downstream activation of signalling cascades is not routinely assessed in development of peptide agonists for this receptor class. The glucagon-like peptide-1 receptor (GLP-1R) is a prototypical class B1 GPCR and a validated target for treatment of global health burdens, including type 2 diabetes and obesity. In this study we examined the kinetics of different steps in GLP-1R activation and subsequent cAMP production mediated by a series of GLP-1R peptide agonists, including the ligand-receptor interaction, ligand-receptor-mediated G protein engagement and conformational change and cAMP production. Our results revealed GLP-1R peptide agonist dissociation kinetics (Koff), but not association kinetics (Kon), were positively correlated with the onset of receptor-G protein coupling/conformational change, onset of cAMP production and duration of cAMP signalling. Thus, this study advances the understanding of molecular events that couple GLP-1R ligand binding to intracellular signaling, with the findings likely to have implications for mechanistic understanding of agonist action at other related class B1 GPCRs.

Dynamics of GLP-1R peptide agonist engagement are correlated with kinetics of G protein activation.

The glucagon-like peptide-1 receptor (GLP-1R) has broad physiological roles and is a validated target for treatment of metabolic disorders. Despite recent advances in GLP-1R structure elucidation, detailed mechanistic understanding of how different peptides generate profound differences in G protein-mediated signalling is still lacking. Here we combine cryo-electron microscopy, molecular dynamics simulations, receptor mutagenesis and pharmacological assays, to interrogate the mechanism and consequences of GLP-1R binding to four peptide agonists; glucagon-like peptide-1, oxyntomodulin, exendin-4 and exendin-P5. These data reveal that distinctions in peptide N-terminal interactions and dynamics with the GLP-1R transmembrane domain are reciprocally associated with differences in the allosteric coupling to G proteins. In particular, transient interactions with residues at the base of the binding cavity correlate with enhanced kinetics for G protein activation, providing a rationale for differences in G protein-mediated signalling efficacy from distinct agonists.

COVID-19 vaccine hesitancy and confidence in the Philippines and Malaysia: A cross-sectional study of sociodemographic factors and digital health literacy.

With the emergence of the highly transmissible Omicron variant, large-scale vaccination coverage is crucial to the national and global pandemic response, especially in populous Southeast Asian countries such as the Philippines and Malaysia where new information is often received digitally. The main aims of this research were to determine levels of hesitancy and confidence in COVID-19 vaccines among general adults in the Philippines and Malaysia, and to identify individual, behavioural, or environmental predictors significantly associated with these outcomes. Data from an internet-based cross-sectional survey of 2558 participants from the Philippines (N = 1002) and Malaysia (N = 1556) were analysed. Results showed that Filipino (56.6%) participants exhibited higher COVID-19 hesitancy than Malaysians (22.9%; p < 0.001). However, there were no significant differences in ratings of confidence between Filipino (45.9%) and Malaysian (49.2%) participants (p = 0.105). Predictors associated with vaccine hesitancy among Filipino participants included women (OR, 1.50, 95% CI, 1.03-1.83; p = 0.030) and rural dwellers (OR, 1.44, 95% CI, 1.07-1.94; p = 0.016). Among Malaysian participants, vaccine hesitancy was associated with women (OR, 1.50, 95% CI, 1.14-1.99; p = 0.004), social media use (OR, 11.76, 95% CI, 5.71-24.19; p < 0.001), and online information-seeking behaviours (OR, 2.48, 95% CI, 1.72-3.58; p < 0.001). Predictors associated with vaccine confidence among Filipino participants included subjective social status (OR, 1.13, 95% CI, 1.54-1.22; p < 0.001), whereas vaccine confidence among Malaysian participants was associated with higher education (OR, 1.30, 95% CI, 1.03-1.66; p < 0.028) and negatively associated with rural dwellers (OR, 0.64, 95% CI, 0.47-0.87; p = 0.005) and online information-seeking behaviours (OR, 0.42, 95% CI, 0.31-0.57; p < 0.001). Efforts should focus on creating effective interventions to decrease vaccination hesitancy, increase confidence, and bolster the uptake of COVID-19 vaccination, particularly in light of the Dengvaxia crisis in the Philippines.

Structural and functional diversity among agonist-bound states of the GLP-1 receptor.

Recent advances in G-protein-coupled receptor (GPCR) structural elucidation have strengthened previous hypotheses that multidimensional signal propagation mediated by these receptors depends, in part, on their conformational mobility; however, the relationship between receptor function and static structures is inherently uncertain. Here, we examine the contribution of peptide agonist conformational plasticity to activation of the glucagon-like peptide 1 receptor (GLP-1R), an important clinical target. We use variants of the peptides GLP-1 and exendin-4 (Ex4) to explore the interplay between helical propensity near the agonist N terminus and the ability to bind to and activate the receptor. Cryo-EM analysis of a complex involving an Ex4 analog, the GLP-1R and Gs heterotrimer revealed two receptor conformers with distinct modes of peptide-receptor engagement. Our functional and structural data, along with molecular dynamics (MD) simulations, suggest that receptor conformational dynamics associated with flexibility of the peptide N-terminal activation domain may be a key determinant of agonist efficacy.

Increasing the human chorionic gonadotrophin cut-off to ≤1000 IU/l for starting actinomycin D in post-molar gestational trophoblastic neoplasia developing resistance to methotrexate spares more women multi-agent chemotherapy.

BACKGROUND: A human chorionic gonadotropin (hCG) cut-off of ≤300 IU/l for starting actinomycin D (ActD) in post-molar gestational trophoblastic neoplasia (GTN) patients developing methotrexate resistance (MTX-R) reduced the number of women needing toxic multi-agent chemotherapy (etoposide, MTX and ActD alternating weekly with cyclophosphamide and vincristine; EMA/CO) without affecting survival. Here we assess whether an increased hCG cut-off of ≤1000 IU/l spares more women EMA/CO. PATIENTS AND METHODS: All post-molar GTN patients treated with first-line methotrexate and folinic acid (MTX/FA) were identified in a national cohort between 2009 and 2016. Data collected included age, FIGO score, the hCG levels at MTX-R, and treatment outcomes. RESULTS: In total, 609 GTN patients commenced treatment with MTX/FA achieving a complete response in 57% (348/609). Resistance developed in 25.1% (153/609) at an hCG ≤ 1000 IU/l and switching to ActD achieved remission in 92.8% without any major toxicity with the remaining 7.2% remitting on EMA/CO. Comparative analysis of patients switching at an hCG <100 versus 100-300 versus 300-1000 IU/l revealed a significant fall in the cure rate with second-line ActD from 97% (93/96) to 87% (34/39) to 78% (14/18), respectively, P = 0.009. However, by increasing the hCG cut-off from ≤300 to ≤1000 IU/l, 14 patients were spared EMA/CO chemotherapy. Moreover, in the present series, all post-molar GTN remain in remission. CONCLUSION: This study demonstrates that increasing the hCG cut-off from ≤300 to ≤1000 IU/l for choosing patients for ActD following MTX-R spares more women with GTN from the greater toxicity of EMA/CO without compromising 100% survival outcomes.

AM833 Is a Novel Agonist of Calcitonin Family G Protein-Coupled Receptors: Pharmacological Comparison with Six Selective and Nonselective Agonists.

Obesity and associated comorbidities are a major health burden, and novel therapeutics to help treat obesity are urgently needed. There is increasing evidence that targeting the amylin receptors (AMYRs), heterodimers of the calcitonin G protein-coupled receptor (CTR) and receptor activity-modifying proteins, improves weight control and has the potential to act additively with other treatments such as glucagon-like peptide-1 receptor agonists. Recent data indicate that AMYR agonists, which can also independently activate the CTR, may have improved efficacy for treating obesity, even though selective activation of CTRs is not efficacious. AM833 (cagrilintide) is a novel lipidated amylin analog that is undergoing clinical trials as a nonselective AMYR and CTR agonist. In the current study, we have investigated the pharmacology of AM833 across 25 endpoints and compared this peptide with AMYR selective and nonselective lipidated analogs (AM1213 and AM1784), and the clinically used peptide agonists pramlintide (AMYR selective) and salmon CT (nonselective). We also profiled human CT and rat amylin as prototypical selective agonists of CTR and AMYRs, respectively. Our results demonstrate that AM833 has a unique pharmacological profile across diverse measures of receptor binding, activation, and regulation. SIGNIFICANCE STATEMENT: AM833 is a novel nonselective agonist of calcitonin family receptors that has demonstrated efficacy for the treatment of obesity in phase 2 clinical trials. This study demonstrates that AM833 has a unique pharmacological profile across diverse measures of receptor binding, activation, and regulation when compared with other selective and nonselective calcitonin receptor and amylin receptor agonists. The present data provide mechanistic insight into the actions of AM833.

Pan-Cancer Analysis of Ligand-Receptor Cross-talk in the Tumor Microenvironment.

Signaling between cancer and nonmalignant (stromal) cells in the tumor microenvironment (TME) is a key to tumor progression. Here, we deconvoluted bulk tumor transcriptomes to infer cross-talk between ligands and receptors on cancer and stromal cells in the TME of 20 solid tumor types. This approach recovered known transcriptional hallmarks of cancer and stromal cells and was concordant with single-cell, in situ hybridization and IHC data. Inferred autocrine cancer cell interactions varied between tissues but often converged on Ephrin, BMP, and FGFR-signaling pathways. Analysis of immune checkpoints nominated interactions with high levels of cancer-to-immune cross-talk across distinct tumor types. Strikingly, PD-L1 was found to be highly expressed in stromal rather than cancer cells. Overall, our study presents a new resource for hypothesis generation and exploration of cross-talk in the TME. SIGNIFICANCE: This study provides deconvoluted bulk tumor transcriptomes across multiple cancer types to infer cross-talk in the tumor microenvironment.

Differential GLP-1R Binding and Activation by Peptide and Non-peptide Agonists.

Peptide drugs targeting class B1 G-protein-coupled receptors (GPCRs) can treat multiple diseases; however, there remains substantial interest in the development of orally delivered non-peptide drugs. Here, we reveal unexpected overlap between signaling and regulation of the glucagon-like peptide-1 (GLP-1) receptor by the non-peptide agonist PF 06882961 and GLP-1 that was not observed for another compound, CHU-128. Compounds from these patent series, including PF 06882961, are currently in clinical trials for treatment of type 2 diabetes. High-resolution cryoelectron microscopy (cryo-EM) structures reveal that the binding sites for PF 06882961 and GLP-1 substantially overlap, whereas CHU-128 adopts a unique binding mode with a more open receptor conformation at the extracellular face. Structural differences involving extensive water-mediated hydrogen bond networks could be correlated to functional data to understand how PF 06882961, but not CHU-128, can closely mimic the pharmacological properties of GLP-1. These findings will facilitate rational structure-based discovery of non-peptide agonists targeting class B GPCRs.

Toward a Structural Understanding of Class B GPCR Peptide Binding and Activation.

Class B G protein-coupled receptors (GPCRs) are important therapeutic targets for major diseases. Here, we present structures of peptide and Gs-bound pituitary adenylate cyclase-activating peptide, PAC1 receptor, and corticotropin-releasing factor (CRF), (CRF1) receptor. Together with recently solved structures, these provide coverage of the major class B GPCR subfamilies. Diverse orientations of the extracellular domain to the receptor core in different receptors are at least partially dependent on evolutionary conservation in the structure and nature of peptide interactions. Differences in peptide interactions to the receptor core also influence the interlinked TM2-TM1-TM6/ECL3/TM7 domain, and this is likely important in their diverse signaling. However, common conformational reorganization of ECL2, linked to reorganization of ICL2, modulates G protein contacts. Comparison between receptors reveals ICL2 as a key domain forming dynamic G protein interactions in a receptor- and ligand-specific manner. This work advances our understanding of class B GPCR activation and Gs coupling.

Activation of the GLP-1 receptor by a non-peptidic agonist.

Class B G-protein-coupled receptors are major targets for the treatment of chronic diseases, including diabetes and obesity1. Structures of active receptors reveal peptide agonists engage deep within the receptor core, leading to an outward movement of extracellular loop 3 and the tops of transmembrane helices 6 and 7, an inward movement of transmembrane helix 1, reorganization of extracellular loop 2 and outward movement of the intracellular side of transmembrane helix 6, resulting in G-protein interaction and activation2-6. Here we solved the structure of a non-peptide agonist, TT-OAD2, bound to the glucagon-like peptide-1 (GLP-1) receptor. Our structure identified an unpredicted non-peptide agonist-binding pocket in which reorganization of extracellular loop 3 and transmembrane helices 6 and 7 manifests independently of direct ligand interaction within the deep transmembrane domain pocket. TT-OAD2 exhibits biased agonism, and kinetics of G-protein activation and signalling that are distinct from peptide agonists. Within the structure, TT-OAD2 protrudes beyond the receptor core to interact with the lipid or detergent, providing an explanation for the distinct activation kinetics that may contribute to the clinical efficacy of this compound series. This work alters our understanding of the events that drive the activation of class B receptors.

O-GlcNAc Engineering of GPCR Peptide-Agonists Improves Their Stability and in Vivo Activity.

Peptide agonists of GPCRs and other receptors are powerful signaling molecules with high potential as biological tools and therapeutics, but they are typically plagued by instability and short half-lives in vivo. Nature uses protein glycosylation to increase the serum stability of secreted proteins. However, these extracellular modifications are complex and heterogeneous in structure, making them an impractical solution. In contrast, intracellular proteins are subjected to a simple version of glycosylation termed O-GlcNAc modification. In our studies of this modification, we found that O-GlcNAcylation inhibits proteolysis, and strikingly, this stabilization occurs despite large distances in primary sequence (10-15 amino acids) between the O-GlcNAc and the site of cleavage. We therefore hypothesized that this "remote stabilization" concept could be useful to engineer the stability and potentially additional properties of peptide or protein therapeutics. Here, we describe the application of O-GlcNAcylation to two clinically important peptides: glucagon-like peptide-1 (GLP-1) and the parathyroid hormone (PTH), which respectively help control glucose and calcium levels in the blood. For both peptides, we found O-GlcNAcylated analogs that are equipotent to unmodified peptide in cell-based activation assays, while several GLP-1 analogs were biased agonists relative to GLP-1. As we predicted, O-GlcNAcylation can improve the stability of both GLP-1 and PTH in serum despite the fact that the O-GlcNAc can be quite remote from characterized sites of peptide cleavage. The O-GlcNAcylated GLP-1 and PTH also displayed significantly improved in vivo activity. Finally, we employed structure-based molecular modeling and receptor mutagenesis to predict how O-GlcNAcylation can be accommodated by the receptors and the potential interactions that contribute to peptide activity. This approach demonstrates the potential of O-GlcNAcylation for generating analogs of therapeutic peptides with enhanced proteolytic stability.

Randomized controlled trial of mechanical bowel preparation for laparoscopy-assisted colectomy.

INTRODUCTION: The benefit of mechanical bowel preparation (MBP) before open colon surgery has been debated over the last decade. The aim of this randomized controlled trial was to evaluate the effect of MBP on the outcome of patients who underwent elective laparoscopic colectomy. METHODS: Patients who were scheduled to undergo elective laparoscopic colon resection with primary anastomosis were randomly allocated to a preoperative MBP group (either two bottles of sodium phosphate or 2-L polyethylene glycol) or a no-MBP group. Anastomotic leakage and other complications such as surgical-site infection and extra-abdominal complications were recorded postoperatively. RESULTS: In this study, 122 patients were recruited and randomly allocated to the MBP group (n = 62) or the no-MBP group (n = 60). Demographic and clinical characteristics were not significantly different between the two groups. The rate of abdominal complications, including anastomotic leak and surgical-site infection, was 16.2% in the MBP group and 18.3% in the no-MBP group (P = 0.747). Anastomotic leakage occurred in four patients (6.5%) in the MBP group and in two patients (3.3%) in no-MBP group (P = 0.680). About 29% of patients in the MBP group still had either liquid or solid content in the bowel. No significant difference was found between the length of hospital stay in the MBP group and the no-MBP group (9.0 ± 2.9 vs 8.4 ± 1.9 days, P = 0.180). CONCLUSIONS: Elective laparoscopic colectomy without MBP is safe and offers acceptable postoperative morbidity.

The lysyl oxidase like 2/3 enzymatic inhibitor, PXS-5153A, reduces crosslinks and ameliorates fibrosis.

Fibrosis is characterized by the excessive deposition of extracellular matrix and crosslinked proteins, in particular collagen and elastin, leading to tissue stiffening and disrupted organ function. Lysyl oxidases are key players during this process, as they initiate collagen crosslinking through the oxidation of the ε-amino group of lysine or hydroxylysine on collagen side-chains, which subsequently dimerize to form immature, or trimerize to form mature, collagen crosslinks. The role of LOXL2 in fibrosis and cancer is well documented, however the specific enzymatic function of LOXL2 and LOXL3 during disease is less clear. Herein, we describe the development of PXS-5153A, a novel mechanism based, fast-acting, dual LOXL2/LOXL3 inhibitor, which was used to interrogate the role of these enzymes in models of collagen crosslinking and fibrosis. PXS-5153A dose-dependently reduced LOXL2-mediated collagen oxidation and collagen crosslinking in vitro. In two liver fibrosis models, carbon tetrachloride or streptozotocin/high fat diet-induced, PXS-5153A reduced disease severity and improved liver function by diminishing collagen content and collagen crosslinks. In myocardial infarction, PXS-5153A improved cardiac output. Taken together these results demonstrate that, due to their crucial role in collagen crosslinking, inhibition of the enzymatic activities of LOXL2/LOXL3 represents an innovative therapeutic approach for the treatment of fibrosis.

Phase-plate cryo-EM structure of a biased agonist-bound human GLP-1 receptor-Gs complex.

The class B glucagon-like peptide-1 (GLP-1) G protein-coupled receptor is a major target for the treatment of type 2 diabetes and obesity. Endogenous and mimetic GLP-1 peptides exhibit biased agonism-a difference in functional selectivity-that may provide improved therapeutic outcomes. Here we describe the structure of the human GLP-1 receptor in complex with the G protein-biased peptide exendin-P5 and a Gαs heterotrimer, determined at a global resolution of 3.3 Å. At the extracellular surface, the organization of extracellular loop 3 and proximal transmembrane segments differs between our exendin-P5-bound structure and previous GLP-1-bound GLP-1 receptor structure. At the intracellular face, there was a six-degree difference in the angle of the Gαs-α5 helix engagement between structures, which was propagated across the G protein heterotrimer. In addition, the structures differed in the rate and extent of conformational reorganization of the Gαs protein. Our structure provides insights into the molecular basis of biased agonism.

Human Mesenchymal Stromal Cell-Derived Extracellular Vesicles Modify Microglial Response and Improve Clinical Outcomes in Experimental Spinal Cord Injury.

No current clinical intervention can alter the course of acute spinal cord injury (SCI), or appreciably improve neurological outcome. Mesenchymal stromal cells (MSCs) have been shown to modulate the injury sequelae of SCI largely via paracrine effects, although the mechanisms remain incompletely understood. One potential modality is through secretion of extracellular vesicles (EVs). In this study, we investigate whether systemic administration of EVs isolated from human MSCs (MSCEv) has the potential to be efficacious as an alternative to cell-based therapy for SCI. Additionally, we investigate whether EVs isolated from human MSCs stimulated with pro-inflammatory cytokines have enhanced anti-inflammatory effects when administered after SCI. Immunohistochemistry supported the quantitative analysis, demonstrating a diminished inflammatory response with apparent astrocyte and microglia disorganization in cord tissue up to 10 mm caudal to the injury site. Locomotor recovery scores showed significant improvement among animals treated with MSCEv. Significant increases in mechanical sensitivity threshold were observed in animals treated with EVs from either naïve MSC (MSCEvwt) or stimulated MSC (MSCEv+), with a statistically significant increase in threshold for MSCEv+-treated animals when compared to those that received MSCEvwt. In conclusion, these data show that treatment of acute SCI with extracellular vesicles derived from human MSCs attenuates neuroinflammation and improves functional recovery.

Dominant Negative G Proteins Enhance Formation and Purification of Agonist-GPCR-G Protein Complexes for Structure Determination.

Advances in structural biology have yielded exponential growth in G protein-coupled receptor (GPCR) structure solution. Nonetheless, the instability of fully active GPCR complexes with cognate heterotrimeric G proteins has made them elusive. Existing structures have been limited to nanobody-stabilized GPCR:Gs complexes. Here we present methods for enhanced GPCR:G protein complex stabilization via engineering G proteins with reduced nucleotide affinity, limiting Gα:Gßγ dissociation. We illustrate the application of dominant negative G proteins of Gαs and Gαi2 to the purification of stable complexes where this was not possible with wild-type G protein. Active state complexes of adenosine:A1 receptor:Gαi2ßγ and calcitonin gene-related peptide (CGRP):CLR:RAMP1:Gαsßγ:Nb35 were purified to homogeneity and were stable in negative stain electron microscopy. These were suitable for structure determination by cryo-electron microscopy at 3.6 and 3.3 Å resolution, respectively. The dominant negative Gα-proteins are thus high value tools for structure determination of agonist:GPCR:G protein complexes that are critical for informed translational drug discovery.

CIB1 contributes to oncogenic signalling by Ras via modulating the subcellular localisation of sphingosine kinase 1.

CIB1 (calcium and integrin binding protein 1) is a small intracellular protein with numerous interacting partners, and hence has been implicated in various cellular functions. Recent studies have revealed emerging roles of CIB1 in regulating cancer cell survival and angiogenesis, although the mechanisms involved have remained largely undefined. In investigating the oncogenic function of CIB1, we initially found that CIB1 is widely up-regulated across a diverse range of cancers, with this upregulation frequently correlating with oncogenic mutations of KRas. Consistent with this, we found that ectopic expression of oncogenic KRas and HRas in cells resulted in elevated CIB1 expression. We previously described the Ca2+-myristoyl switch function of CIB1, and its ability to facilitate agonist-induced plasma membrane localisation of sphingosine kinase 1 (SK1), a location where SK1 is known to elicit oncogenic signalling. Thus, we examined the role this may play in oncogenesis. Consistent with these findings, we demonstrated here that over-expression of CIB1 by itself is sufficient to drive localisation of SK1 to the plasma membrane and enhance the membrane-associated enzymatic activity of SK1, as well as its oncogenic signalling. We subsequently demonstrated that elevated levels of CIB1 resulted in full neoplastic transformation, in a manner dependent on SK1. In agreement with our previous findings that SK1 is a downstream mediator of oncogenic signalling by Ras, we found that targeting CIB1 also inhibited neoplastic growth of cells induced by oncogenic Ras, suggesting an important pro-tumorigenic role for CIB1. Thus, we have demonstrated for the first time a role for CIB1 in neoplastic transformation, and revealed a novel mechanism facilitating oncogenic signalling by Ras and SK1.

Outcomes of a Clinical Pathway for Borderline Resectable Pancreatic Cancer.

BACKGROUND: Without prospective data establishing a consensus multimodality approach to borderline resectable pancreatic adenocarcinoma, institutional treatment regimens vary. This study investigated the outcomes of the clinical pathway at the author's institution, which consists of neoadjuvant gemcitabine, docetaxel, capecitabine, and stereotactic radiotherapy followed by surgery. METHODS: The study reviewed all cases that met the National Comprehensive Cancer Network (NCCN) diagnostic criteria for borderline resectable pancreatic adenocarcinoma from 1 January 2006, to 31 December 2013. Pancreatectomy rates, margin status, pathologic response, disease-free survival (DFS), disease-specific survival (DSS), and overall survival (OS) were retrospectively examined. Standard statistical methods and Kaplan-Meier survival analysis were used for statistical comparisons. RESULTS: Of 121 patients who met criteria, 101 entered the clinical pathway, and 94 (93.1 %) completed neoadjuvant chemotherapy and radiation therapy. Of the 101 patients, 55 (54.5 %) underwent pancreatectomy, with 53 patients (96.4 %) having microscopically negative margins (R0) and 2 patients (3.6 %) having microscopically positive margins (R1). Vascular resection was required for 22 patients (40 %), with rates of 95.5 % for R0 (n = 21) and 4.5 % for R1 (n = 1). A pathologic response to treatment was demonstrated by 45 patients (81.8 %) and a complete response by 10 patients (14.5 %). Pancreatectomy resulted in a median DFS of 23 months (95 % conflidence interval [CI] 14.5-31.5), a median DSS of 43 months (95 % CI, 25.7-60.3), and a median OS of 33 months (95 % CI, 25.0-41.0) versus a median DSS and OS of 14 months (95 % CI, 10.9-17.1) for patients without pancreatectomy (DSS: P = 3.5 × 10(-13); OS: P = 4.7 × 10(-10)). CONCLUSIONS: The study demonstrated high rates for neoajduvant therapy completion (93.1 %) and pancreatectomy (54.5 %). After pancreatectomy, DSS was significantly improved (43 months), with a pathologic response demonstrated by 81.8 % and a complete response by 14.5 % of the patients. The results support further study of this borderline resectable pancreatic adenocarcinoma clinical pathway.