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Despite their low abundance, phosphoinositides play a central role in membrane traffic and signalling. PtdIns(3,4,5)P

SummaryThe PIP3/PI3K network is a central regulator of metabolism and is frequently activated in cancer, commonly by loss of the PIP3/PI(3,4)P2-phosphatase, PTEN. Despite huge investment, the drivers of the PI3K network in normal tissues and how they adapt to overactivation are unclear.We find that in healthy mouse prostate PI3K activity is driven by RTK/IRS signalling and constrained by pathway-feedback. In the absence of PTEN, the network is dramatically remodelled. A poorly understood, YXXM and PIP3/PI(3,4)P2-binding PH domain-containing, adaptor, PLEKHS1, became the dominant activator and was required to sustain PIP3, AKT-phosphorylation and growth in PTEN-null prostate. This was because PLEKHS1 evaded pathway-feedback and experienced enhanced PI3K and SRC-family kinase-dependent phosphorylation of Y258XXM, eliciting PI3K activation.hPLEKHS1-mRNA and activating-Y419-phosphorylation of hSRC correlated with PI3K-pathway activity in human prostate cancers. We propose that in PTEN-null cells, receptor-independent, SRC-dependent tyrosine-phosphorylation of PLEKHS1 creates positive-feedback that escapes homeostasis, drives PIP3- signalling and supports tumour progression.

Effect of the Pdk1 L155E allele on the incidence of hyperplasia, solid nodules, and carcinomas in male Ptenthyr-/- mice at 60 weeks of age.

Activation of the PI3K–AKT signaling cascade is a common critical event during malignant transformation. In this study, we used thyroid gland epithelial cells and a series of genetically engineered mouse strains as model systems to demonstrate that, although necessary, AKT activation is not sufficient for PI3K-driven transformation. Instead, transformation requires the activity of the PDK1-regulated AGC family of protein kinases. In particular, SGK1 was found to be essential for proliferation and survival of thyroid cancer cells harboring PI3K-activating mutations. Notably, cotargeting SGK1 and AKT resulted in significantly higher growth suppression than inhibiting either PI3K or AKT alone. Overall, these findings underscore the clinical relevance of AKT-independent pathways in tumors driven by genetic lesions targeting the PI3K cascade. Cancer Res; 77(24); 6914–26. ©2017 AACR.

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Platelets utilize signal transduction pathways facilitated by Class I phosphatidylinositol transfer proteins (PITPs). The two mammalian Class I PITPs, PITPα and PITPβ, are single PITP domain soluble proteins that are encoded by different genes and have 77% sequence identity, though their individual roles in mammalian biology remain uncharacterized. These proteins are believed to shuttle phosphatidylinositol and phosphatidylcholine between separate intracellular membrane compartments, thereby regulating phosphoinositide synthesis and second messenger formation. Previously, we observed that platelet-specific deletion of PITPα, the predominant expressed murine PITP isoform, had no effect on hemostasis, but had impaired tumor metastasis formation and disrupted phosphoinositide signaling. Here, we find that mice lacking the lesser expressed PITPβ in their platelets exhibit a similar phenotype. However, in contrast to PITPα-null platelet lysates that have impaired lipid transfer activity, PITPβ-null platelet lysates have essentially normal lipid transfer activity, although both isoforms contribute to phosphoinositide synthesis in vitro. Moreover, we found that platelet-specific deletion of both PITPs leads to ex vivo platelet aggregation/secretion and spreading defects, impaired tail bleeding, and profound tumor dissemination. Our studies also demonstrate that PITP isoforms are required for maintaining endogenous phosphoinositide PI(4,5)P2 levels and agonist stimulated second messenger formation. The data shown here demonstrate that both class I PITP isoforms contribute to phosphoinositide signaling in platelets, likely through distinct biochemical mechanisms or in different subcellular domains. They are functionally overlapping and either single isoform is able to maintain the homeostasis of platelets.

Abnormalities in the endosomal-autophagic-lysosomal (EAL) system are an early event in Alzheimer's disease (AD) pathogenesis. However, the mechanisms underlying these abnormalities are unclear. The transient receptor potential channel mucolipin 1(TRPML1, also known as MCOLN1), a vital endosomal-lysosomal Ca2+ channel whose loss of function leads to neurodegeneration, has not been investigated with respect to EAL pathogenesis in late-onset AD (LOAD). Here, we identify pathological hallmarks of TRPML1 dysregulation in LOAD neurons, including increased perinuclear clustering and vacuolation of endolysosomes. We reveal that induced pluripotent stem cell (iPSC)-derived human cortical neurons expressing APOE ε4, the strongest genetic risk factor for LOAD, have significantly diminished TRPML1-induced endolysosomal Ca2+ release. Furthermore, we found that blocking TRPML1 function in primary neurons by depleting the TRPML1 agonist PI(3,5)P2 via PIKfyve inhibition, recreated multiple features of EAL neuropathology evident in LOAD. This included increased endolysosomal Ca2+ content, enlargement and perinuclear clustering of endolysosomes, autophagic vesicle accumulation and early endosomal enlargement. Strikingly, these AD-like neuronal EAL defects were rescued by TRPML1 reactivation using its synthetic agonist ML-SA1. These findings implicate defects in TRPML1 in LOAD EAL pathogenesis and present TRPML1 as a potential therapeutic target.

Receptor tyrosine kinases such as epidermal growth factor (EGF) receptor (EGFR) stimulate phosphatidylinositol 3-kinases (PI3Ks) to convert phosphaitydlinositol-4,5-bisphosophate [PtdIns(4,5)P2] into phosphatidylinositol-3,4,5-trisphosphate [PtdIns(3,4,5)P3]. PtdIns(3,4,5)P3then promotes various pathways leading to actin remodelling, changes in gene expression, and enhanced anabolic activity, cell survival and proliferation. In part, PtdIns(3,4,5)P3achieves these functions by stimulating the kinase Akt, which phosphorylates numerous targets like Tsc2 and GSK3β. Overall, unchecked upregulation of PtdIns(3,4,5)P3-Akt signalling can promote tumourgenesis and cancer progression. Interestingly, 50-70% of PtdIns and PtdInsPs have stearate and arachidonate atsn-1 andsn-2 positions of glycerol, respectively, forming a species known as 38:4-PtdIns/PtdInsPs. It is thought that LCLAT1/LYCAT and MBOAT7/LPIAT1 acyltransferases are respectively responsible for enriching PtdIns with this acyl composition. We previously showed that disruption of LCLAT1 altered the acyl profile of bis-phosphorylated PtdInsPs, lowered PtdIns(4,5)P2, and perturbed endocytosis and endocytic trafficking. However, the role of LCLAT1 in receptor tyrosine kinase and PtdIns(3,4,5)P3signaling was not explored. Here, we show that LCLAT1 silencing in MDA-MB-231 and ARPE-19 cells abated the levels of PtdIns(3,4,5)P3in response to EGF signalling. Importantly, LCLAT1-silenced cells were also impaired for EGF-mediated Akt activation and downstream signalling, and consequently, were depressed for cell proliferation and survival. Thus, our work provides first evidence that the LCLAT1 acyltransferase supports receptor tyrosine kinase signalling through the PtdIns(3,4,5)P3-Akt axis and may represent a novel target for therapeutic development against cancers.

SRX246, an orally available CNS penetrant vasopressin (VP) V1a receptor antagonist, was studied in Huntington’s disease (HD) patients with irritability and aggressive behavior in the exploratory phase 2 trial, Safety, Tolerability, and Activity of SRX246 in Irritable HD patients (STAIR). This was a dose-escalation study; subjects received final doses of 120 mg BID, 160 mg BID, or placebo. The compound was safe and well tolerated. In this paper, we summarize the results of exploratory analyses of measures of problematic behaviors, including the Cohen–Mansfield Agitation Inventory (CMAI), Aberrant Behavior Checklist (ABC), Problem Behaviors Assessment-short form (PBA-s), Irritability Scale (IS), Clinical Global Impression (CGI), HD Quality of Life (QoL), and Caregiver Burden questionnaires. In addition to these, we asked subjects and caregivers to record answers to short questions about mood, irritability, and aggressive conduct in an eDiary. STAIR was the first rigorously designed study of behavioral endpoints like these in HD. The exploratory analyses showed that SRX246 reduced aggressive acts. Readily observed behaviors should be used as trial endpoints.

Upon antigen binding, the B cell receptor (BCR) undergoes clustering to form a signalosome that propagates downstream signaling required for normal B cell development and physiology. BCR clustering is dependent on remodeling of the cortical actin network, but the mechanisms that regulate actin remodeling in this context remain poorly defined. In this study, we identify the inositol 5-phosphatase INPP5B as a key regulator of actin remodeling, BCR clustering, and downstream signaling in antigen-stimulated B cells. INPP5B acts via dephosphorylation of the inositol lipid PI(4,5)P2 that in turn is necessary for actin disassembly, BCR mobilization, and cell spreading on immobilized surface antigen. These effects can be explained by increased actin severing by cofilin and loss of actin linking to the plasma membrane by ezrin, both of which are sensitive to INPP5B-dependent PI(4,5)P2 hydrolysis. INPP5B is therefore a new player in BCR signaling and may represent an attractive target for treatment of B cell malignancies caused by aberrant BCR signaling.

BackgroundDeutetrabenazine is a vesicular monoamine transporter 2 inhibitor approved for the treatment of tardive dyskinesia (TD) in adults. In two 12-week pivotal studies, deutetrabenazine demonstrated statistically significant improvements in Abnormal Involuntary Movement Scale (AIMS) scores, with favorable safety/tolerability in TD patients. This study reports long-term efficacy and safety of deutetrabenazine in a 3-year, single-arm, open-label extension (OLE) study.MethodsPatients who completed the pivotal studies could enroll in this single-arm OLE study, titrating up to 48 mg/day based on dyskinesia control and tolerability. Efficacy was assessed based on change from baseline in total motor AIMS score, Clinical Global Impression of Change (CGIC) and Patient Global Impression of Change (PGIC), and quality of life (QOL) assessments. Safety evaluation included adverse event (AE) incidence, reported using exposure-adjusted incidence rates, and safety scales.Results343 patients enrolled in the study (6 patients were excluded). At Week 145 (mean dose: 39.4 ± 0.83 mg/day), mean ± SE change from baseline in total motor AIMS score was −6.6 ± 0.37 and 67% of patients achieved ≥50% improvement in total motor AIMS score. Based on CGIC and PGIC, 73% and 63% of patients achieved treatment success, respectively. QOL improvements were also observed. Deutetrabenazine was generally well tolerated, with low rates of mild-to-moderate AEs and no new safety signals; most safety scales remained unchanged over time.ConclusionsLong-term deutetrabenazine treatment was associated with sustained improvement in AIMS scores, indicative of clinically meaningful long-term benefit, and was generally well tolerated. Results suggest deutetrabenazine may provide increasing benefit over time without increases in dose.

IntroductionDeutetrabenazine is FDA-approved for the treatment of tardive dyskinesia (TD) in adults. In two 12-week pivotal trials (ARM-TD/AIM-TD), deutetrabenazine significantly improved Abnormal Involuntary Movement Scale (AIMS) scores and was well-tolerated. This post hoc analysis examined the efficacy and safety of long-term deutetrabenazine treatment in TD patients with comorbid psychiatric illness, including schizophrenia/schizoaffective disorder and mood disorders (bipolar/depression/other).MethodsPatients who completed ARM-TD or AIM-TD enrolled in the 3-year, open-label extension (OLE) study. Deutetrabenazine was titrated based on dyskinesia control and tolerability. Change from baseline in total motor AIMS score, Patient Global Impression of Change (PGIC), Clinical Global Impression of Change (CGIC), and adverse events (AEs) were analyzed in subgroups by comorbid psychiatric illness.ResultsA total of 337 patients in the OLE study were included in the analysis: 205 patients with schizophrenia/schizoaffective disorder (mean age, 55 years; 50% male; 6.4 years since diagnosis; 92% taking DRA) and 131 patients with mood disorders (mean age, 60 years; 35% male; 4.6 years since diagnosis; 50% taking DRA). At week 145, mean ± SE dose was 40.4 ± 1.1 mg/day for schizophrenia/schizoaffective disorder (n = 88) and 38.5 ± 1.2 mg/day for mood disorders (n = 72). Mean ± SE change from baseline in AIMS score at week 145 was −6.3 ± 0.49 and −7.1 ± 0.58, 56% and 72% achieved PGIC treatment success, and 66% and 82% achieved CGIC treatment success in schizophrenia/schizoaffective disorder and mood disorder patients, respectively. Overall AE incidence (exposure-adjusted incidence rates [incidence/patient-years]) was low: any, 1.02 and 1.71; serious, 0.10 and 0.12; leading to discontinuation, 0.07 and 0.05).ConclusionLong-term deutetrabenazine treatment provided clinically meaningful improvements in TD-related movements, with a favorable safety profile, regardless of underlying comorbid psychiatric illness.FundingTeva Pharmaceutical Industries Ltd., Petach Tikva, Israel

Rates of genetic testing in Huntington disease (HD) are lower than was predicted before direct DNA testing became available. Clinicians often do not have in-depth conversations with people at risk who chose not to test. We queried 733 research subjects who chose not to learn their HD gene status when enrolling in the Prospective Huntington At-Risk Observational Study, carried out between 1999 and 2008. Lack of an effective cure or treatment (66% of subjects) and inability to undo knowledge (66%) were the major reasons cited for choosing not to undergo HD DNA testing. Most subjects were not concerned about the length or burden of the testing process (61% and 59%, respectively). Subjects were optimistic that a treatment to improve symptoms or postpone onset would be developed within the next 10 years (56% and 53%, respectively), but they had less certainty about the prospects to prevent HD onset (36%). This is the first large, systematic study of why people at risk for HD choose not to undergo genetic testing. Attitudes about how people at risk for HD approach this life-altering choice should be reassessed as new treatments develop, and as clinical trials now require genetic testing at entry.

Co-occurring somatoform symptoms complicate the diagnosis and treatment of Parkinson disease (PD).To learn more about the relationship between somatoform symptoms and PD by comparing demographic and clinical features across PD groups differing in somatoform symptom severity.Using standardized Brief Symptom Inventory-18 (BSI-18) scores to measure somatoform symptom severity, we assigned 1093 individuals with PD to one of four subgroups using comparisons to normative means: low (M-½ SD), average (M ± ½ SD), high (M +½ SD to +1 SD), very high (M+1 SD). We used demographics and disease severity measures to assess each subgroup.Most of the individuals with PD (56%) had high or very high somatoform symptom levels. Increased somatoform symptom levels were associated with female gender, lower socioeconomic status, greater disease duration, increased PD severity (Total Unified Parkinson's Disease Rating Scale), greater disability (Older Americans Resource and Services Disability subscale), increased BSI-18 Depression and Anxiety subscale scores, lower cognitive function (Mini-Mental State Examination), lower self-efficacy scores (Self-Efficacy to Manage Chronic Disease Scale), lower quality of life scores (SF-12 Health Status Survey), and greater medical comorbidity (Cumulative Illness Rating Scale-Geriatrics) (all comparisons: P0.001). We found no significant between-group differences for age, race, or marital status.Somatoform symptom severity in individuals with PD is associated with greater PD severity and disability and is more common in females and in individuals with low socioeconomic status. Greater awareness of somatoform symptoms should help improve PD treatment.

Introduction: An understanding of the clinimetric properties of clinical assessments, including their constraints, is critical to sound clinical study and trial design. Utilizing data from Enroll-HD—a global, prospective HD observational study and clinical research platform—we examined several well-established HD clinical assessments across all stages of disease for evidence of instrument constraints, specifically floor/ceiling effects, to inform selection of appropriate instruments for use in future studies/trials and identify gaps in instrument utility over the life-course of the disease.Material and Methods: Analyzing publicly available data from 6,614 HD gene-expansion carriers (HDGECs), we grouped participants into deciles based on baseline CAP score, which ranged from 26 to 229. We used descriptive statistics to characterize data distribution for 25 outcome measures (encompassing motor, function, cognition, and psychiatric/behavioral domains) in each CAP decile. A skewness statistic threshold of ±2 was defined a priori to indicate floor/ceiling effects.Results: We found evidence of floor/ceiling effects in the early premanifest stages of disease for most motor and function assessments (e.g., TMS, TFC) and select cognitive tasks (MMSE, Trail Making tests). Other cognitive assessments, and the HADS-SIS scales, performed well ubiquitously, with no evidence of floor/ceiling effects at any disease stage. Floor/ceiling effects were evident at every disease stage for certain assessments, including PBA-s measures. Ceiling effects were apparent for DCL from onset stages onwards, as expected.Discussion: Developing instruments sensitive to subtle differences in performance at the earlier stages of the disease spectrum, particularly in motor and function domains, is warranted.

Significance The stereotype of ROS produced by NADPH oxidases as cause of malignant diseases persists in a generalized manner. In fact, high levels of ROS formation could be harmful in the context of a disease process. This study demonstrates that loss of the NADPH oxidase Nox4, as a constitutive source of ROS, promotes cancerogen-induced formation of solid tumors. Accordingly, a certain tonic, constitutive low level of Nox4-derived hydrogen peroxide appears to reduce the risk of cancerogen-induced tumor formation., Reactive oxygen species (ROS) can cause cellular damage and promote cancer development. Besides such harmful consequences of overproduction of ROS, all cells utilize ROS for signaling purposes and stabilization of cell homeostasis. In particular, the latter is supported by the NADPH oxidase 4 (Nox4) that constitutively produces low amounts of H2O2. By that mechanism, Nox4 forces differentiation of cells and prevents inflammation. We hypothesize a constitutive low level of H2O2 maintains basal activity of cellular surveillance systems and is unlikely to be cancerogenic. Utilizing two different murine models of cancerogen-induced solid tumors, we found that deletion of Nox4 promotes tumor formation and lowers recognition of DNA damage. Nox4 supports phosphorylation of H2AX (γH2AX), a prerequisite of DNA damage recognition, by retaining a sufficiently low abundance of the phosphatase PP2A in the nucleus. The underlying mechanism is continuous oxidation of AKT by Nox4. Interaction of oxidized AKT and PP2A captures the phosphatase in the cytosol. Absence of Nox4 facilitates nuclear PP2A translocation and dephosphorylation of γH2AX. Simultaneously AKT is left phosphorylated. Thus, in the absence of Nox4, DNA damage is not recognized and the increased activity of AKT supports proliferation. The combination of both events results in genomic instability and promotes tumor formation. By identifying Nox4 as a protective source of ROS in cancerogen-induced cancer, we provide a piece of knowledge for understanding the role of moderate production of ROS in preventing the initiation of malignancies.

SRX246 is a vasopressin (AVP) 1a receptor antagonist that crosses the blood-brain barrier. It reduced impulsive aggression, fear, depression and anxiety in animal models, blocked the actions of intranasal AVP on aggression/fear circuits in an experimental medicine fMRI study and demonstrated excellent safety in Phase 1 multiple-ascending dose clinical trials. The present study was a 3-arm, multicenter, randomized, placebo-controlled, double-blind, 12-week, dose escalation study of SRX246 in early symptomatic Huntington&rsquo, s disease (HD) patients with irritability. Our goal was to determine whether SRX246 was safe and well tolerated in these HD patients given its potential use for the treatment of problematic neuropsychiatric symptoms. Participants were randomized to receive placebo or to escalate to 120 mg twice daily or 160 mg twice daily doses of SRX246. Assessments included standard safety tests, the Unified Huntington&rsquo, s Disease Rating Scale (UHDRS), and exploratory measures of problem behaviors. The groups had comparable demographics, features of HD and baseline irritability. Eighty-two out of 106 subjects randomized completed the trial on their assigned dose of drug. One-sided exact-method confidence interval tests were used to reject the null hypothesis of inferior tolerability or safety for each dose group vs. placebo. Apathy and suicidality were not affected by SRX246. Most adverse events in the active arms were considered unlikely to be related to SRX246. The compound was safe and well tolerated in HD patients and can be moved forward as a candidate to treat irritability and aggression.

The PI3Kγ isoform is activated by Gi-coupled GPCRs in myeloid cells, but the extent to which the two endogenous complexes of PI3Kγ, p101/p110γ and p84/p110γ, receive direct regulation through Gβγ or indirect regulation through RAS and the sufficiency of those inputs is controversial or unclear. We generated mice with point mutations that prevent Gβγ binding to p110γ (RK552DD) or to p101 (VVKR777AAAA) and investigated the effects of these mutations in primary neutrophils and in mouse models of neutrophilic inflammation. Loss of Gβγ binding to p110γ substantially reduced the activation of both p101/p110γ and p84/p110γ in neutrophils by various GPCR agonists. Loss of Gβγ binding to p101 caused more variable effects, depending on both the agonist and cellular response, with the biggest reductions seen in PIP3 production by primary neutrophils in response to LTB4 and MIP-2 and in the migration of neutrophils during thioglycolate-induced peritonitis or MIP2-induced ear pouch inflammation. We also observed that p101(VVKR777AAAA) neutrophils showed enhanced p84-dependent ROS responses to fMLP and C5a, suggesting that competition may exist between p101/p110γ and p84/p110γ for Gβγ subunits downstream of GPCR activation. GPCRs did not activate p110γ in neutrophils from mice lacking both the p101 and p84 regulatory subunits, indicating that RAS binding to p110γ is insufficient to support GPCR activation in this cell type. These findings define a direct role for Gβγ subunits in activating both of the endogenous PI3Kγ complexes and indicate that the regulatory PI3Kγ subunit biases activation towards different GPCRs.

**Background:** Huntington’s disease (HD) is a multifaceted neurodegenerative disorder characterized by involuntary movements, specifically chorea, as well as behavioral and psychiatric disturbance, and cognitive dysfunction. Tetrabenazine was the first approved treatment for chorea, although tolerability concerns exist. **Objectives:** To characterize demographic and clinical characteristics of HD patients with chorea based on tetrabenazine use and examine treatment persistence with tetrabenazine in a real-world setting. **Methods:** Patients with a claim for HD-associated chorea (ICD-9-CM code 333.4) between 1/1/08 and 9/30/15 were selected from the MarketScan® Commercial and Medicare Supplemental databases. The first diagnosis date during the study period was considered the index date, with ≥6 months of continuous medical and prescription coverage before and after the index date. Treatment persistence was defined as the number of days from initiation to discontinuation or end of follow-up period. Discontinuation was defined as a gap in therapy of ≥60 days. **Results:** 1644 patients met selection criteria (mean age ± standard deviation: 54.5 ± 15.5), of which 151 (9.2%) were treated with tetrabenazine during the study period. The average (median) daily dose of tetrabenazine during the treatment period was 45.5 (42.3) mg/day. A total of 41.8% (59/141) of HD patients who initiated tetrabenazine experienced a ≥60-day gap in tetrabenazine therapy, with a median time to discontinuation of 293.5 days. During the 6-month post-index period after HD diagnosis, HD patients incurred higher all-cause healthcare costs ($20 204) vs the 6-month pre-index period ($6057), driven by higher hospitalization and pharmacy costs. **Conclusions:** A small percentage of HD patients with chorea were treated with tetrabenazine and discontinuation rates were high among those receiving treatment, with a median time to discontinuation of 9 months.

IntroductionTardive dyskinesia (TD) is an involuntary movement disorder that can result from exposure to dopamine-receptor antagonists (DRAs). Deutetrabenazine demonstrated significant improvements in Abnormal Involuntary Movement Scale (AIMS) scores in the 12-week pivotal trials (ARM-TD/AIM-TD). This post hoc analysis assessed the long-term efficacy and safety of deutetrabenazine by baseline DRA use.MethodsPatients who completed ARM-TD or AIM-TD enrolled in the 3-year, open-label extension (OLE) study, with deutetrabenazine dose titrated based on dyskinesia control and tolerability. Change from baseline in total motor AIMS score, Patient Global Impression of Change (PGIC), Clinical Global Impression of Change (CGIC), and adverse event (AE) rates were analyzed in subgroups by baseline DRA use.ResultsOf 337 patients in the OLE study, 254 were taking DRAs at baseline (mean age, 56 years; 48% male; 6.0 years since diagnosis) and 83 were not (mean age, 60 years; 31% male; 4.9 years since diagnosis). Mean ± SE dose at week 145 was 39.9 ± 1.0 mg/day in patients taking DRAs (n = 108) and 38.5 ± 1.5 mg/day in patients not taking DRAs (n = 53). At week 145, mean ± SE change from baseline in AIMS score was −6.1 ± 0.43 and −7.5 ± 0.71; 64% and 62% achieved PGIC treatment success; and 69% and 81% achieved CGIC treatment success, respectively. Overall AE incidence was low (exposure-adjusted incidence rates [incidence/patient-years]: any, 1.08 and 1.97; serious, 0.10 and 0.12; leading to discontinuation, 0.06 and 0.05).ConclusionThis analysis suggests that deutetrabenazine for long-term treatment of TD is beneficial, with a favorable safety profile, regardless of concomitant DRA use.FundingTeva Pharmaceutical Industries Ltd., Petach Tikva, Israel

BackgroundDeutetrabenazine, a novel vesicular monoamine transporter 2 (VMAT2) inhibitor, is approved by the FDA for treatment of tardive dyskinesia (TD) in adults. Dopamine-receptor antagonists (DRAs) are associated with worsening of metabolic parameters, including weight gain, hyperlipidemia, and elevated blood glucose. This post hoc analysis assessed the short- and long-term effects of deutetrabenazine treatment on weight and metabolic parameters in individuals treated for TD.MethodsTwo 12-week, randomized placebo-controlled trials (RCTs) of deutetrabenazine for patients with TD evaluated either fixed dosing (AIM-TD; 12, 24, or 36 mg) or dose titration (ARM-TD; max dose, 48 mg/day). Patients completing ARM-TD or AIM-TD were included in an open-label extension (OLE) study, in which all patients underwent response-driven titration of deutetrabenazine from 12 mg/day up to a maximum total dose of 48 mg/day. Weight, body mass index (BMI), serum glucose, serum total cholesterol, and serum triglycerides were evaluated at baseline and during treatment in the RCTs and in the OLE.ResultsIn the RCTs, 282 and 133 patients received deutetrabenazine or placebo. At baseline, 77% of patients used DRAs. At Week 12, no meaningful changes in weight were observed, with mean (standard error) weight changes of 0.9–1.2 (0.3–0.5) and 0.2 (0.3) kg in the deutetrabenazine and placebo groups, respectively, and mean BMI changes of 0.3–0.5 (0.1–0.2) and 0.1 (0.1) kg/m2. 337 patients were included in the analysis of the OLE study. No meaningful changes were observed in weight (mean change: 0.4 [0.4] kg at Week 54, –0.5 [0.6] kg at Week 106, and –1.1 [0.6] kg at Week 145) or BMI (mean change: 0.1 [0.2] kg/m2 at Week 54, –0.2 [0.2] kg/m2 at Week 106, and –0.3 [0.2] kg/m2 at Week 145). Across the studies, no meaningful changes were observed in triglyceride, cholesterol, or glucose levels.ConclusionDeutetrabenazine does not affect common metabolic parameters in patients with TD, even during long-term exposure.FundingTeva Pharmaceutical Industries Ltd., Petach Tikva, Israel

Activation of the PI3K–AKT signaling cascade is a common critical event during malignant transformation. In this study, we used thyroid gland epithelial cells and a series of genetically engineered mouse strains as model systems to demonstrate that, although necessary, AKT activation is not sufficient for PI3K-driven transformation. Instead, transformation requires the activity of the PDK1-regulated AGC family of protein kinases. In particular, SGK1 was found to be essential for proliferation and survival of thyroid cancer cells harboring PI3K-activating mutations. Notably, cotargeting SGK1 and AKT resulted in significantly higher growth suppression than inhibiting either PI3K or AKT alone. Overall, these findings underscore the clinical relevance of AKT-independent pathways in tumors driven by genetic lesions targeting the PI3K cascade. Cancer Res; 77(24); 6914–26. ©2017 AACR.

Summary Background Tardive dyskinesia results from exposure to dopamine receptor antagonists, such as typical and atypical antipsychotics. If clinically appropriate, clinicians often manage this disorder by lowering the dose of, or discontinuing, the causative drug. There is a significant unmet need for a treatment option that does not disrupt treatment regimens for underlying psychiatric illnesses. We aimed to assess the efficacy, safety, and tolerability of fixed doses of deutetrabenazine—a novel vesicular monoamine transporter-2 inhibitor—in patients with tardive dyskinesia. Methods We did this double-blind, randomised, placebo-controlled, phase 3 trial at 75 centres in the USA and Europe. Patients aged 18–80 years with tardive dyskinesia (≥3 months before screening) were randomly assigned centrally (1:1:1:1), via interactive response technology, to receive one of three fixed doses of deutetrabenazine (12 mg/day, 24 mg/day, or 36 mg/day) or matching placebo. Randomisation was stratified by baseline use of dopamine receptor antagonists. Patients were started on oral deutetrabenazine 12 mg/day, and this dose was increased through week 4 until the randomised dose was achieved, then maintained over 8 weeks. During the treatment period, patients, investigators, their site personnel, and sponsor were masked to group assignment. The primary efficacy endpoint was change in Abnormal Involuntary Movement Scale (AIMS) score from baseline to week 12 in patients with at least one post-baseline rating. The primary efficacy analysis was done in the modified intention-to-treat population (baseline AIMS score ≥6 and at least one post-baseline rating). The safety analysis was done in patients who received any study drug. This trial is registered with ClinicalTrials.gov, number NCT02291861. Findings Between Oct 29, 2014, and Aug 19, 2016, we randomly assigned 298 patients to receive at least one dose of placebo (n=74), deutetrabenazine 12 mg/day (n=75), 24 mg/day (n=74), or 36 mg/day (n=75); 222 patients comprised the modified intention-to-treat population and 293 patients comprised the safety population. From baseline to week 12, the least-squares mean AIMS score improved by −3·3 points (SE 0·42) in the deutetrabenazine 36 mg/day group, −3·2 points (0·45) in the 24 mg/day group, and −2·1 points (0·42) in the 12 mg/day group, with a treatment difference of −1·9 points (SE 0·58, 95% CI −3·09 to −0·79; p=0·001), −1·8 points (0·60, −3·00 to −0·63; p=0·003), and −0·7 points (0·57, −1·84 to 0·42; p=0·217), respectively, versus −1·4 points (0·41) in the placebo group. The rate of adverse events was similar between patients in the deutetrabenazine 36 mg/day group (n=38/74 [51%]), 24 mg/day group (n=32/73 [44%]), and 12 mg/day group (n=36/74 [49%]), and those in the placebo group (n=34/72 [47%]). Serious adverse events were reported in four (5%) patients given deutetrabenazine 36 mg/day, six (8%) patients given 24 mg/day, and two (3%) patients given 12 mg/day, compared with four (6%) patients given placebo. Two (1%) patients in the safety population died, one each in the deutetrabenazine 24 mg/day and 36 mg/day groups; neither death was deemed related to study drug by the investigator or sponsor. Interpretation Deutetrabenazine 24 mg/day and 36 mg/day provided a significant reduction in tardive dyskinesia, with favourable safety and tolerability. These findings suggest that dosing regimens could be individualised and tailored for patients on the basis of dyskinesia control and tolerability. Funding Teva Pharmaceutical Industries.

Dissecting the logic of individual signaling modules in complex networks can be challenging for cascades that exhibit feedback and redundancy. In this study, Graziano et al. take an optogenetics-based approach to identify and dissect a module that converts sustained PIP3 production to transient Rac activation in the neutrophil chemotaxis signaling network., Sensory systems use adaptation to measure changes in signaling inputs rather than absolute levels of signaling inputs. Adaptation enables eukaryotic cells to directionally migrate over a large dynamic range of chemoattractant. Because of complex feedback interactions and redundancy, it has been difficult to define the portion or portions of eukaryotic chemotactic signaling networks that generate adaptation and identify the regulators of this process. In this study, we use a combination of optogenetic intracellular inputs, CRISPR-based knockouts, and pharmacological perturbations to probe the basis of neutrophil adaptation. We find that persistent, optogenetically driven phosphatidylinositol (3,4,5)-trisphosphate (PIP3) production results in only transient activation of Rac, a hallmark feature of adaptive circuits. We further identify the guanine nucleotide exchange factor P-Rex1 as the primary PIP3-stimulated Rac activator, whereas actin polymerization and the GTPase-activating protein ArhGAP15 are essential for proper Rac turnoff. This circuit is masked by feedback and redundancy when chemoattractant is used as the input, highlighting the value of probing signaling networks at intermediate nodes to deconvolve complex signaling cascades.