Efficacy and safety outcomes of dulaglutide by baseline HbA1c: A post hoc analysis of the REWIND trial.

AIM: To assess cardiovascular, glycaemic, weight and safety outcomes of long-term treatment with dulaglutide 1.5 mg compared with placebo in patients with a baseline HbA1c of less than 7% versus 7% or higher. MATERIALS AND METHODS: Intention-to-treat analyses were performed on REWIND participants with a baseline HbA1c measurement, using Cox proportional hazards regression and mixed model for repeated measures. Subgroup analyses with factors for baseline HbA1c categories and their interaction with treatment group, as well as analyses within the HbA1c subgroups, were conducted. Additionally, sensitivity analyses were performed for baseline HbA1c subgroups of 6.5% or less and more than 6.5%. RESULTS: Of the 9876 eligible participants, 3921 and 5955 had a baseline HbA1c of less than 7% and 7% or higher, respectively. Mean baseline HbA1c was 6.3% and 8.0% and the mean duration of diabetes was 9.0 and 11.6 years in the respective subgroups. The less than 7% subgroup was slightly older and less frequently insulin-treated. There was no evidence of a differential dulaglutide treatment effect on body mass index (BMI) reduction, cardiovascular or safety outcomes of interest between the baseline HbA1c subgroups. Treatment-by-baseline HbA1c group interaction was significant for HbA1c change from baseline (P < .001), with a greater reduction in the subgroup with higher baseline HbA1c values. Sensitivity analyses by baseline HbA1c subgroups of 6.5% or less and more than 6.5% showed similar results. CONCLUSIONS: The reduced incidence of cardiovascular events, and the reduction in BMI in participants treated with once-weekly dulaglutide, were independent of the baseline HbA1c level. Conversely, participants with a higher baseline HbA1c level had greater reductions in HbA1c. Dulaglutide has a positive benefit-risk profile and can be considered in patients with comparatively well-controlled HbA1c levels seeking optimal metabolic control and cardiovascular benefits.

A close association of freedom from pain, migraine-related functional disability, and other outcomes: results of a post hoc analysis of randomized lasmiditan studies SAMURAI and SPARTAN.

BACKGROUND: While pain freedom at 2 h is a key primary outcome for current trials for acute treatment of migraine, the relationship between the degree of head pain and other efficacy measures at 2 h has rarely been explored. Following lasmiditan treatment of a migraine attack with moderate or severe head pain, we contrast those who achieve pain freedom with those who achieve mild pain but not pain freedom 2 h post dosing. METHODS: Patient-level data were pooled across studies and treatment arms from two Phase 3 trials comparing lasmiditan and placebo, SAMURAI and SPARTAN. This post hoc analysis assessed freedom from the most bothersome symptom (MBS), freedom from migraine-related functional disability (disability), and improved patient global impression of change (PGIC) in patients who achieved 2 h pain freedom compared to those who experienced 2 h mild pain. Mild pain differs from pain relief which is defined as either mild pain or pain freedom. RESULTS: Patients who achieved 2 h pain freedom (N = 913), in comparison with those with 2 h mild pain (N = 864), were significantly more likely to experience MBS freedom (91.9% vs. 44.9%), disability freedom (87.1% and 13.4%), and improved PGIC (86.5% and 31.5%) (p < 0.001 for all combinations). In addition, more patients who were pain free experienced both 2 h MBS freedom and 2 h functional disability freedom (83.6%) compared to those with mild pain (10.8%; p < 0.001). The proportion of patients with pain freedom who did not achieve either MBS or disability freedom (4.6%) was lower than in patients with mild pain (52.4%). Lastly, 55.2% of patients experienced mild pain before disability freedom compared to 72.1% who experienced pain freedom and disability freedom at the same time. CONCLUSIONS: This study demonstrated that, at 2 h post treatment, patients who were pain free were more likely to achieve other outcomes including freedom from their MBS, freedom from migraine-related functional disability, and improved PGIC compared to those with mild pain, confirming that 2 h pain freedom is more robustly associated with other clinical outcomes than the 2 h mild pain endpoint. TRIAL REGISTRATION: SAMURAI ( NCT02439320 ); SPARTAN ( NCT02605174 ).

Lasmiditan for the acute treatment of migraine: Subgroup analyses by prior response to triptans.

BACKGROUND: Lasmiditan demonstrated superiority to placebo in the acute treatment of migraine in adults with moderate/severe migraine disability in two similarly designed Phase 3 trials, SAMURAI and SPARTAN. Post-hoc integrated analyses evaluated the efficacy of lasmiditan in patients who reported a good or insufficient response to triptans and in those who were triptan naïve. METHODS: Subgroups of patients reporting an overall response of "good" or "poor/none" to the most recent use of a triptan at baseline (defined as good or insufficient responders, respectively) and a triptan-naïve subpopulation were derived from combined study participants randomized to receive lasmiditan 50 mg (SPARTAN only), 100 mg or 200 mg, or placebo, as the first dose. Outcomes including headache pain-freedom, most bothersome symptom-freedom, and headache pain relief 2 hours post-first dose of lasmiditan were compared with placebo. Treatment-by-subgroup analyses additionally investigated whether therapeutic benefit varied according to prior triptan response (good or insufficient). RESULTS: Regardless of triptan response, lasmiditan showed higher efficacy than placebo (most comparisons were statistically significant). Treatment-by-subgroup analyses found that the benefit over placebo of lasmiditan did not vary significantly between patients with a good response and those with an insufficient response to triptans. Lasmiditan also showed higher efficacy than placebo in triptan-naïve patients. CONCLUSIONS: Lasmiditan demonstrated comparable efficacy in patients who reported a good or insufficient response to prior triptan use. Lasmiditan also showed efficacy in those who were triptan naïve. Lasmiditan may be a useful therapeutic option for patients with migraine. TRIAL REGISTRATION: SAMURAI (NCT02439320); SPARTAN (NCT02605174).

Trajectory of migraine-related disability following long-term treatment with lasmiditan: results of the GLADIATOR study.

BACKGROUND: Migraine is recognized as the second leading cause of disability globally. Lasmiditan is a novel, selective serotonin 5-HT1F receptor agonist developed for acute treatment of migraine. Here we analyzed effects of lasmiditan on migraine disability assessed with the Migraine Disability Assessment (MIDAS) scale for interim data from a long-term safety study. METHODS: Completers of two single-attack parent studies were offered participation in the 1 year GLADIATOR study, that randomized participants to treatment with lasmiditan 100 mg or 200 mg taken as needed for migraine attacks of at least moderate severity. Changes in MIDAS were modeled using a mixed model repeated measures analysis. RESULTS: The sample included 1978 patients who received ≥1 lasmiditan dose and were followed for a median of 288 days. Baseline mean MIDAS scores for the lasmiditan 100-mg and 200-mg groups were 29.4 and 28.9, respectively, indicating severe migraine-related disability. Relative to baseline, MIDAS total scores were significantly lower at 3, 6, 9, and 12 months for both dose groups. At 12 months, changes in MIDAS scores were - 12.5 and - 12.2 for lasmiditan 100 mg and 200 mg, respectively, with 49% and 53% of patients, respectively, achieving at least a 50% decrease in MIDAS total score. Statistically significant improvements were also seen for work and/or school absenteeism and presenteeism, monthly headache days, and mean headache pain intensity at all time points up to 1 year. Findings for patients who completed all visits versus those dropping out early were similar. Responses were generally similar for the lasmiditan 100 mg or 200 mg doses, between subgroups defined based on the number of baseline monthly migraine attacks (≤5 vs. >5), and also between subgroups defined by pain-free response (yes/no) during initial attacks. CONCLUSIONS: Long-term treatment with lasmiditan was associated with significant reductions in migraine-related disability, including both work or school absenteeism and presenteeism. The similarity of responses in completers and those who dropped out suggests that selective attrition does not account for the improvements. Benefits were significant at 3 months and maintained through 12 months. TRIAL REGISTRATION: clinicaltrials.govNCT02565186; first posted October 1, 2015.

Effect of a rescue or recurrence dose of lasmiditan on efficacy and safety in the acute treatment of migraine: findings from the phase 3 trials (SAMURAI and SPARTAN).

BACKGROUND: We studied the efficacy and safety of a second dose of lasmiditan for acute treatment of migraine. METHODS: SAMURAI and SPARTAN were double-blind, placebo-controlled Phase 3 studies in which individuals with migraine were randomized to oral lasmiditan 50 mg (SPARTAN only), 100 mg, 200 mg, or placebo. Study drug was to be taken within 4 h (h) of onset of a migraine attack (moderate or severe pain). A second dose of study drug was provided for rescue (patient not pain-free at 2 h and took a second dose 2-24 h post-first dose) or recurrence (patient pain-free at 2 h, but experienced recurrence of mild, moderate, or severe migraine pain and took a second dose 2-24 h after first dose). Randomization to second dose occurred at baseline; patients originally assigned lasmiditan were randomized to the same lasmiditan dose or placebo (2:1 ratio), and those originally assigned placebo received placebo. Data from SAMURAI and SPARTAN were pooled for efficacy and safety assessment of a second dose of lasmiditan. RESULTS: The proportion of patients taking a second dose was lower with lasmiditan versus placebo, and decreased with increasing lasmiditan dose; the majority who took a second dose did so for rescue. In patients taking lasmiditan as first dose, outcomes (pain free, most bothersome symptom [MBS] free) at 2 h after a second dose for rescue were similar whether the second dose was lasmiditan or placebo (p > 0.05 in all cases). In patients taking lasmiditan for first dose, outcomes at 2 h after a second dose for recurrence were as follows: lasmiditan pooled versus placebo - pain free, 50% vs 32% (p > 0.05); MBS free, 71% vs 41% (p = 0.02); pain relief, 77% vs 52% (p = 0.03). In patients whose first dose was lasmiditan, the incidence of treatment emergent adverse events (TEAEs) reported after the second dose was similar whether second dose was lasmiditan or placebo. CONCLUSIONS: A second dose of lasmiditan showed some evidence of efficacy when taken for headache recurrence. There was no clear benefit of a second dose of lasmiditan for rescue treatment. The incidences of TEAEs were similar whether the second dose was lasmiditan or placebo. TRIAL REGISTRATION: SAMURAI ( NCT02439320 ) [April 2015]. SPARTAN ( NCT02605174 ) [May 2016].

Efficacy and safety of lasmiditan in patients using concomitant migraine preventive medications: findings from SAMURAI and SPARTAN, two randomized phase 3 trials.

OBJECTIVE: To study the efficacy and safety of lasmiditan for acute treatment of migraine in patients using migraine preventive medications. BACKGROUND: While lasmiditan has been proven to be an effective acute treatment for migraine, its effectiveness has not been examined when used concurrently with migraine preventives. METHODS: SAMURAI and SPARTAN were similarly designed, double-blind, phase 3, placebo-controlled studies of patients 18 years or older with 3 to 8 migraine attacks per month. Patients were randomized to treat a migraine attack with oral lasmiditan 50 mg (SPARTAN only), 100 mg, 200 mg, or placebo. Migraine preventives were allowed as long as doses were stable for 3 months prior to screening and were unchanged during the study. Preventive medications with established or probable efficacy, as recommended by the American Academy of Neurology, the American Headache Society, and the European Headache Federation, plus botulinum toxin type A and candesartan, were included. Within the subgroups of patients using and not using preventive therapies, lasmiditan and placebo groups were analyzed for the outcome of pain-free at 2 h and other efficacy outcomes. The subgroups of patients using and not using preventive therapies were compared and interaction p-values were calculated for safety and efficacy outcomes. RESULTS: In these trials, 698 of 3981 patients (17.5%) used migraine preventive treatments. Among patients using preventives, all lasmiditan doses resulted in significantly more patients being pain-free at 2 h, compared to placebo (p < 0.05). Primary efficacy outcome (pain-free at 2 h), key secondary outcome (most bothersome symptom-free at 2 h) and all other efficacy outcomes were not significantly different between patients using or not using migraine preventives (all interaction p-values ≥0.1). Rates of adverse events were similar for patients using and not using preventive medications. CONCLUSIONS: Lasmiditan was more effective than placebo for the acute treatment of migraine in patients concurrently using migraine preventive medications. Lasmiditan efficacy and safety measures were similar for patients using and not using preventive medications. TRIAL REGISTRATION: SAMURAI (NCT02439320) and SPARTAN (NCT02605174). Registered 18 March 2015.

Practical Applications of a Nausea and Vomiting Model in the Clinical Development of Additional Doses of Dulaglutide.

Dulaglutide 3.0 and 4.5 mg weekly doses were approved for additional glycemic control in adult patients with type 2 diabetes inadequately controlled with metformin and 0.75 or 1.5 mg weekly doses of dulaglutide. Effects such as nausea and vomiting are commonly reported with dulaglutide and other glucagon-like peptide-1 receptor agonist therapies. Based on a pharmacokinetic/pharmacodynamic model-informed approach, a stepwise dose-escalation scheme with 4-week intervals between dose increments was suggested to mitigate gastrointestinal events for dulaglutide. These gastrointestinal events are dose dependent and attenuate over time with repeated dosing. A Markov chain Monte Carlo pharmacokinetic/pharmacodynamic joint model was developed using AWARD-11 data (N = 1842) to optimize dulaglutide dose escalation to 3.0 and 4.5 mg to mitigate gastrointestinal events. Model simulations evaluated probabilities of nausea and vomiting events for various dosing scenarios in patients needing higher doses for additional glycemic control. The model indicated that patients may dose escalate from 1.5 to 3.0 mg, then 4.5 mg weekly after at least 4 weeks on each dose. No clinically meaningful differences in nausea or vomiting events were expected when patients escalated to 3.0 or 4.5 mg following initiation at 0.75 or 1.5 mg dulaglutide. Based on the findings of this model, a minimum 4-week duration at each dose before escalation was appropriate to reduce gastrointestinal events of dulaglutide, consistent with observed gastrointestinal events data from the AWARD-11 study and supporting the currently recommended dose-escalation regimen of dulaglutide doses of 3.0 and 4.5 mg for additional glycemic control.

Participation of Tom1L1 in EGF-stimulated endocytosis of EGF receptor.

Although many proteins have been shown to participate in ligand-stimulated endocytosis of EGF receptor (EGFR), the adaptor protein responsible for interaction of activated EGFR with endocytic machinery remains elusive. We show here that EGF stimulates transient tyrosine phosphorylation of Tom1L1 by the Src family kinases, resulting in transient interaction of Tom1L1 with the activated EGFR bridged by Grb2 and Shc. Cytosolic Tom1L1 is recruited onto the plasma membrane and subsequently redistributes into the early endosome. Mutant forms of Tom1L1 defective in Tyr-phosphorylation or interaction with Grb2 are incapable of interaction with EGFR. These mutants behave as dominant-negative mutants to inhibit endocytosis of EGFR. RNAi-mediated knockdown of Tom1L1 inhibits endocytosis of EGFR. The C-terminal tail of Tom1L1 contains a novel clathrin-interacting motif responsible for interaction with the C-terminal region of clathrin heavy chain, which is important for exogenous Tom1L1 to rescue endocytosis of EGFR in Tom1L1 knocked-down cells. These results suggest that EGF triggers a transient Grb2/Shc-mediated association of EGFR with Tyr-phosphorylated Tom1L1 to engage the endocytic machinery for endocytosis of the ligand-receptor complex.

Budget impact of lasmiditan for the acute treatment of migraine in the United States.

BACKGROUND: Three novel acute treatments for migraine-lasmiditan, ubrogepant, and rimegepant-were approved by the FDA in 2019 and 2020 for adults with migraine with and without aura. American Headache Society guidance recommends that these novel acute treatments be considered for patients who are contraindicated to or fail to respond or tolerate oral triptans, the current standard of acute care. OBJECTIVE: To estimate, from a US commercial plan perspective, the budget impact of adding lasmiditan as an option to a formulary that already includes ubrogepant and rimegepant. METHODS: Epidemiologic data were drawn from US Census data, the American Migraine Prevalence and Preventive study, and the first wave of the OVERCOME US survey, a web-based survey that included 21,000 patients with migraine. A model with a 3-year time horizon was built assuming that demand for the novel acute treatments would not vary based on whether lasmiditan is included in the formulary. The model examined a variety of populations, in particular beneficiaries with previous use of 1 or more oral triptans or contraindicated to triptans and beneficiaries with previous use of 2 or more oral triptans or contraindicated to triptans. Primary outcomes were the incremental differences in total cost and average cost per member per month (PMPM) between scenarios with and without lasmiditan. One-way sensitivity analyses with model parameters that were varied by plus or minus 15% were conducted to assess the effect of key parameters on the incremental total cost over 3 years. RESULTS: The addition of lasmiditan to a formulary that already includes ubrogepant and rimegepant resulted in a total savings of -$927,657 (-1.5% compared with the scenario without lasmiditan) over a 3-year time horizon in the population with previous history of using 1 or more oral triptans or contraindicated to a triptan. In the population with previous history of using 2 or more oral triptans or contraindicated, the addition of lasmiditan resulted in a total budget impact of -$466,518 (-1.3%) over a 3-year time horizon. Most of the cost savings was attributable to reductions in drug acquisition cost. Savings in total costs resulted in average incremental cost per PMPM of -0.03 and -$0.01, respectively. CONCLUSIONS: The addition of lasmiditan to the formulary as a novel acute treatment option for migraine alongside ubrogepant and rimegepant resulted in lower budget impact on a 3-year time horizon from a US commercial payer's perspective. This result is important to US commercial payers as they seek to incorporate the emerging novel acute treatments for migraine into their benefit designs. DISCLOSURES: This work was funded by Eli Lilly and Company. Milev and Sun are employed by Evidera, which received funding from Eli Lilly and Company for work on this project. Pohl, Mason, Njuguna, and Loo are employees and stockholders of Eli Lilly and Company.

A role for endobrevin/VAMP8 in CTL lytic granule exocytosis.

CTL clear virus-infected cells and tumorigenic cells by releasing potent cytotoxic enzymes stored in preformed lytic granules. The exocytosis process includes polarization of lytic granules toward the immunological synapse, tethering of lytic granules to the plasma membrane and finally fusion of lytic granules with the plasma membrane to release cytotoxic enzymes. Although much is known about the molecular machineries necessary for the earlier steps in lytic granule exocytosis, the molecular machinery governing the final step in the fusion process has not been identified. Here, we show using control and VAMP8 KO mice that VAMP8 is localized to the CTL lytic granules. While the immunological synapse and granule polarization appears normal in both VAMP8 KO and control CTL, CTL-mediated killing was reduced for the Vamp8(-/-) CTL. Analysis of lytic enzyme secretion demonstrated that granzyme A and granzyme B secretion is significantly compromised in VAMP8(-/-) CTL, while the levels of the lytic enzymes in the cells are unaffected. Our results clearly show that VAMP8 is one of the v-SNARE that regulate the lytic ability of CTL by influencing the ability of the lytic granules to fuse with the plasma membrane and release its contents.

Evaluation of Patients with Insufficient Efficacy and/or Tolerability to Triptans for the Acute Treatment of Migraine: A Systematic Literature Review.

INTRODUCTION: Use of triptans for acute treatment of migraine is associated with insufficient efficacy and/or tolerability in approximately 30-40% of people. We conducted a systematic literature review (SLR) to synthesize definitions, terminology, subsequent treatment outcomes, and characteristics associated with this subpopulation. METHODS: A comprehensive SLR was conducted to identify studies, published from Jan 1995 to May 2019, which focused on insufficient efficacy and/or tolerability to triptans. RESULTS: Thirty-five publications were identified, of which 22 described randomized controlled trials and open-label studies, and 13 described observational studies. Across studies, multiple objectives and a high amount of variability in methodologies and outcomes were noted. The most commonly applied measures of efficacy were headache pain freedom and pain relief at 2 h. Ten studies assessed efficacy of switching or optimizing treatment in patients with historical insufficient efficacy or tolerability to previous triptan treatment and demonstrated varying levels of success. Factors associated with increased risk of triptan insufficient efficacy included severe baseline headache severity, photophobia, phonophobia, nausea, and depression. CONCLUSIONS: Irrespective of the methodology or definition used to identify people with insufficient efficacy and/or tolerability to triptans, study results support the assertion that a high unmet need remains for effective acute treatment of migraine.

Abuse Potential of Lasmiditan: A Phase 1 Randomized, Placebo- and Alprazolam-Controlled Crossover Study.

Lasmiditan is a centrally penetrant, highly selective 5-hydroxytryptamine (serotonin) receptor 1F (5HT1F ) agonist under development as a novel therapy for acute treatment of migraine. A phase 1 randomized, placebo- and positive-controlled crossover study assessed the abuse potential of lasmiditan in adult recreational polydrug users. Following a qualification phase, subjects were randomized into treatment sequences, each consisting of 5 study treatments: placebo, alprazolam 2 mg, lasmiditan 100, 200 (lasmiditan 100 and 200 mg are proposed therapeutic doses), and 400 mg (supratherapeutic). The abuse potential of lasmiditan was investigated and compared with alprazolam and with placebo using the maximal effect score (Emax ) of the Drug-Liking Visual Analog Scale as the primary end point. Lasmiditan was not similar to placebo in drug-liking scores at all doses tested, with a maximum difference observed with the lasmiditan 400-mg dose (upper 90% confidence limit on difference in least-squares [LS] means > 14 for all lasmiditan doses). Drug-liking scores for lasmiditan 400 mg were not significantly different from alprazolam (lower 90% confidence limit on difference in LS means < 5), but drug-liking scores at lower doses (100 and 200 mg) were significantly different from alprazolam. During the treatment phase, the incidence of treatment-emergent adverse events (TEAEs) increased with increasing dose of lasmiditan; all TEAEs reported with lasmiditan treatment were mild. Subjective drug-liking effects for lasmiditan versus placebo and versus alprazolam, and the safety and tolerability profile of lasmiditan suggest that lasmiditan has a low potential for abuse.

Impaired volume regulation is the mechanism of excitotoxic sensitization to complement.

Previous work demonstrated that a brief, sublethal excitotoxic insult strikingly increased the sensitivity of cortical neurons to the cytotoxic effects of the terminal pathway of complement, a process termed "excitotoxic sensitization." Here, we sought to elucidate the cellular mechanism of excitotoxic sensitization in embryonic rat cortical neurons in vitro. Excitotoxic sensitization did not increase membrane attack complex deposition on cortical neurons and produced only a small reduction of membrane attack complex removal, because of a selective decrease of endocytic elimination. Membrane attack complexes and other osmotic stressors, namely hypotonic stress and glutamate, induced transient swelling of cortical neurons, followed by return to normal volume despite persistence of the stressor, a homeostatic response termed regulatory volume decrease (RVD). A minimal excitotoxic insult impaired this homeostatic response and sensitized neurons to cytotoxic effects of diverse osmotic stressors. Structurally distinct membrane-impermeable osmolytes, dextran and polyethylene glycol, prevented excitotoxic sensitization to diverse osmotic stressors including membrane attack complexes. Paraquat, a reactive oxygen species generator, alone was sufficient to impair RVD, and MnTBAP [Mn(III)tetrakis(4-benzoic acid)porphyrin chloride], a reactive oxygen species scavenger, prevented excitotoxin-mediated impairment of RVD. Together, these findings demonstrate that impairment of RVD is the mechanism of excitotoxic sensitization, that reactive oxygen species alone are sufficient to impair RVD, and that reactive oxygen species are necessary for excitotoxic sensitization-mediated impairment of RVD.

Sorting nexin 27 couples PTHR trafficking to retromer for signal regulation in osteoblasts during bone growth.

The parathyroid hormone 1 receptor (PTHR) is central to the process of bone formation and remodeling. PTHR signaling requires receptor internalization into endosomes, which is then terminated by recycling or degradation. Here we show that sorting nexin 27 (SNX27) functions as an adaptor that couples PTHR to the retromer trafficking complex. SNX27 binds directly to the C-terminal PDZ-binding motif of PTHR, wiring it to retromer for endosomal sorting. The structure of SNX27 bound to the PTHR motif reveals a high-affinity interface involving conserved electrostatic interactions. Mechanistically, depletion of SNX27 or retromer augments intracellular PTHR signaling in endosomes. Osteoblasts genetically lacking SNX27 show similar disruptions in PTHR signaling and greatly reduced capacity for bone mineralization, contributing to profound skeletal deficits in SNX27-knockout mice. Taken together, our data support a critical role for SNX27-retromer mediated transport of PTHR in normal bone development.

An oncogenic role of Agrin in regulating focal adhesion integrity in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths globally. The identity and role of cell surface molecules driving complex biological events leading to HCC progression are poorly understood, hence representing major lacunae in HCC therapies. Here, combining SILAC quantitative proteomics and biochemical approaches, we uncover a critical oncogenic role of Agrin, which is overexpressed and secreted in HCC. Agrin enhances cellular proliferation, migration and oncogenic signalling. Mechanistically, Agrin's extracellular matrix sensor activity provides oncogenic cues to regulate Arp2/3-dependent ruffling, invadopodia formation and epithelial-mesenchymal transition through sustained focal adhesion integrity that drives liver tumorigenesis. Furthermore, Agrin signalling through Lrp4-muscle-specific tyrosine kinase (MuSK) forms a critical oncogenic axis. Importantly, antibodies targeting Agrin reduced oncogenic signalling and tumour growth in vivo. Together, we demonstrate that Agrin is frequently upregulated and important for oncogenic property of HCC, and is an attractive target for antibody therapy.

A role for sorting nexin 27 in AMPA receptor trafficking.

Sorting nexin 27 (SNX27), a PDZ domain-containing endosomal protein, was recently shown to modulate glutamate receptor recycling in Down's syndrome. However, the precise molecular role of SNX27 in GluA1 trafficking is unclear. Here we report that SNX27 is enriched in dendrites and spines, along with recycling endosomes. Significantly, the mobilization of SNX27 along with recycling endosomes into spines was observed. Mechanistically, SNX27 interacts with K-ras GTPase via the RA domain; and following chemical LTP stimuli, K-ras is recruited to SNX27-enriched endosomes through a Ca(2+)/CaM-dependent mechanism, which in turn drives the synaptic delivery of homomeric GluA1 receptors. Impairment of SNX27 prevents LTP and associated trafficking of AMPARs. These results demonstrate a role for SNX27 in neuronal plasticity, provide a molecular explanation for the K-ras signal during LTP and identify SNX27 as the PDZ-containing molecular linker that couples the plasticity stimuli to the delivery of postsynaptic cargo.

Loss of sorting nexin 27 contributes to excitatory synaptic dysfunction by modulating glutamate receptor recycling in Down's syndrome.

Sorting nexin 27 (SNX27), a brain-enriched PDZ domain protein, regulates endocytic sorting and trafficking. Here we show that Snx27(-/-) mice have severe neuronal deficits in the hippocampus and cortex. Although Snx27(+/-) mice have grossly normal neuroanatomy, we found defects in synaptic function, learning and memory and a reduction in the amounts of ionotropic glutamate receptors (NMDA and AMPA receptors) in these mice. SNX27 interacts with these receptors through its PDZ domain, regulating their recycling to the plasma membrane. We demonstrate a concomitant reduced expression of SNX27 and CCAAT/enhancer binding protein ß (C/EBPß) in Down's syndrome brains and identify C/EBPß as a transcription factor for SNX27. Down's syndrome causes overexpression of miR-155, a chromosome 21-encoded microRNA that negatively regulates C/EBPß, thereby reducing SNX27 expression and resulting in synaptic dysfunction. Upregulating SNX27 in the hippocampus of Down's syndrome mice rescues synaptic and cognitive deficits. Our identification of the role of SNX27 in synaptic function establishes a new molecular mechanism of Down's syndrome pathogenesis.

Deficiency of sorting nexin 27 (SNX27) leads to growth retardation and elevated levels of N-methyl-D-aspartate receptor 2C (NR2C).

Phox (PX) domain-containing sorting nexins (SNXs) are emerging as important regulators of endocytic trafficking. Sorting nexin 27 (SNX27) is unique, as it contains a PDZ (Psd-95/Dlg/ZO1) domain. We show here that SNX27 is primarily targeted to the early endosome by interaction of its PX domain with PtdIns(3)P. Although targeted ablation of the SNX27 gene in mice did not significantly affect growth and survival during embryonic development, SNX27 plays an essential role in postnatal growth and survival. N-Methyl-d-aspartate (NMDA) receptor 2C (NR2C) was identified as a novel SNX27-interacting protein, and this interaction is mediated by the PDZ domain of SNX27 and the C-terminal PDZ-binding motif of NR2C. Increased NR2C expression levels, together with impaired NR2C endocytosis in SNX27(-/-) neurons, indicate that SNX27 may function to regulate endocytosis and/or endosomal sorting of NR2C. This is consistent with a role of SNX27 as a general regulator for sorting of membrane proteins containing a PDZ-binding motif, and its absence may alter the trafficking of these proteins, leading to growth and survival defects.

p125A exists as part of the mammalian Sec13/Sec31 COPII subcomplex to facilitate ER-Golgi transport.

Coat protein II (COPII)-mediated export from the endoplasmic reticulum (ER) involves sequential recruitment of COPII complex components, including the Sar1 GTPase, the Sec23/Sec24 subcomplex, and the Sec13/Sec31 subcomplex. p125A was originally identified as a Sec23A-interacting protein. Here we demonstrate that p125A also interacts with the C-terminal region of Sec31A. The Sec31A-interacting domain of p125A is between residues 260-600, and is therefore a distinct domain from that required for interaction with Sec23A. Gel filtration and immunodepletion studies suggest that the majority of cytosolic p125A exists as a ternary complex with the Sec13/Sec31A subcomplex, suggesting that Sec 13, Sec31A, and p125A exist in the cytosol primarily as preassembled Sec13/Sec31A/p125A heterohexamers. Golgi morphology and protein export from the ER were affected in p125A-silenced cells. Our results suggest that p125A is part of the Sec13/Sec31A subcomplex and facilitates ER export in mammalian cells.

TEADs mediate nuclear retention of TAZ to promote oncogenic transformation.

The transcriptional coactivators YAP and TAZ are downstream targets inhibited by the Hippo tumor suppressor pathway. The expression level of TAZ is recently shown to be elevated in invasive breast cancer cells and some primary breast cancers. TAZ is important for breast cancer cell migration, invasion, and tumorigenesis, but the underlying mechanism is not defined. In this study, we show that TAZ interacts with TEAD transcriptional factors. Knockdown of TEADs suppresses TAZ-mediated oncogenic transformation of MCF10A cells. Uncoupling TAZ from Hippo regulation by S89A mutation enhances its transforming ability. Several residues located in the N-terminal region of TAZ are identified to be important for interaction with TEADs, and these same residues are equally important for TAZ to transform MCF10A cells. Mechanistically, TAZ mutants defective in interaction with TEADs fail to accumulate in the nucleus. Live cell imaging of enhanced green fluorescent protein-TAZ and its mutant defective in TEAD interaction suggests that TEAD interaction mediates nuclear retention. These results reveal a novel mechanism for TEADs to regulate nuclear retention and thus the transforming ability of TAZ.