Alzheimer's disease-associated P460L variant of EphA1 dysregulates receptor activity and blood-brain barrier function.

INTRODUCTION: Genome-wide association studies link susceptibility to late-onset Alzheimer's disease (LOAD) with EphA1. Sequencing identified a non-synonymous substitution P460L as a LOAD risk variant. Other Ephs regulate vascular permeability and immune cell recruitment. We hypothesized that P460L dysregulates EphA1 receptor activity and impacts neuroinflammation. METHODS: EphA1/P460L receptor activity was assayed in isogenic Human Embryonic Kidney (HEK) cells. Soluble EphA1/P460L (sEphA1/sP460L) reverse signaling in brain endothelial cells was assessed by T-cell recruitment and barrier function assays. RESULTS: EphA1 and P460L were expressed in HEK cells, but membrane and soluble P460L were significantly reduced. Ligand engagement induced Y781 phosphorylation of EphA1 but not P460L. sEphA1 primed brain endothelial cells for increased T-cell recruitment; however, sP460L was less effective. sEphA1 decreased the integrity of the brain endothelial barrier, while sP460L had no effect. DISCUSSION: These findings suggest that P460L alters EphA1-dependent forward and reverse signaling, which may impact blood-brain barrier function in LOAD. HIGHLIGHTS: EphA1-dependent reverse signaling controls recruitment of T cells by brain endothelial cells. EphA1-dependent reverse signaling remodels brain endothelial cell contacts. LOAD-associated P460L variant of EphA1 shows reduced membrane expression and reduced ligand responses. LOAD-associated P460L variant of EphA1 fails to reverse signal to brain endothelial cells.

Cabozantinib plus docetaxel and prednisone in metastatic castration-resistant prostate cancer.

OBJECTIVE: To evaluate the safety and efficacy of cabozantinib combined with docetaxel. PATIENTS AND METHODS: This was a phase 1/2 multicentre study in patients with metastatic castration-resistant prostate cancer (mCRPC). Docetaxel (75 mg/m2 every 3 weeks with daily prednisone 10 mg) was combined with escalating doses of daily cabozantinib (20, 40 and 60 mg). Based on the results of the phase 1 study, the investigation was expanded into a randomized study of docetaxel with prednisone (hereafter 'docetaxel/prednisone') plus the maximum tolerated dose (MTD) of cabozantinib compared with docetaxel/prednisone alone. RESULTS: A total of 44 men with mCRPC were enrolled in this phase 1/2 trial. An MTD of 40 mg cabozantinib plus docetaxel/prednisone was determined. Dose-limiting toxicities were neutropenic fever and palmar-plantar erythrodysesthesia, and there was one death attributable to a thromboembolic event. In addition, grade 3 or 4 myelosuppression, hypophosphataemia and neuropathy were seen in three or more patients. In the phase 1 study, the median time to progression (TTP) and overall survival (OS) time were 13.6 and 16.3 months, respectively. In the phase 2 study, which was terminated early because of poor accrual, the median TTP and OS favoured the combination (n = 13) compared to docetaxel/prednisone alone (n = 12; 21.0 vs 6.6 months; P = 0.035 and 23.8 vs 15.6 months; P = 0.072, respectively). CONCLUSION: Despite the limited number of patients in this study, preliminary data suggest that cabozantinib can be safely added to docetaxel/prednisone with possible enhanced efficacy.

Anaplastic Features in Advanced Prostate Cancer With and Without DNA Damage Repair Mutations.

BACKGROUND: Anaplastic prostate cancer has a poor prognosis with limited treatment options. Seven clinical features of anaplastic prostate cancer have been prospectively identified. In this phase II clinical trial, we identified mutations, including DNA damage repair (DDR) mutations, in patients with metastatic castration-resistant prostate cancer (mCRPC) who were treated with durvalumab and olaparib and determined how many of them can be described as anaplastic, and we examined the overlap between anaplastic features and DDR mutations. METHODS: Eligible patients with mCRPC received prior enzalutamide, abiraterone, or both. Patients were treated with durvalumab 1500 mg i.v. every 28 days and olaparib 300 mg p.o. every 12 hours until disease progression or unacceptable toxicity. Patients underwent mandatory baseline biopsies of metastatic lesions. RESULTS: Baseline characteristics were similar between anaplastic and nonanaplastic patients. Eleven patients (20%) displayed clear anaplastic features, and 43 (78.2%) lacked anaplastic features. In the anaplastic group, 2/11 (18.2%) had germline DRR mutations, and 4/11 (36.3%) had somatic DDR mutations. In the nonanaplastic group, 7/43 (16.3%) had germline mutations, and 13/43 (30.2%) had somatic mutations. Median progression-free survival (PFS) times in patients with anaplastic features (6.5 months) and without anaplastic features (5.1 months) were similar (hazard ratio 0.998, P = .996). CONCLUSIONS: Patients with and without anaplastic features appear to have similar total rates of DDR mutations and also similar rates of somatic and germline DDR mutations. Patients with anaplastic features have a trend toward improved PFS when treated with olaparib and durvalumab compared with nonanaplastic patients.

Clinical and immunologic impact of short-course enzalutamide alone and with immunotherapy in non-metastatic castration sensitive prostate cancer.

BACKGROUND: The standard treatment for non-metastatic castration sensitive prostate cancer (nmCSPC) is androgen deprivation therapy (ADT) or surveillance. This study evaluated the potential synergy of immunotherapy and enzalutamide (without ADT) in nmCSPC. In addition, the immunologic impact of enzalutamide was also evaluated in men with normal testosterone. METHODS: Patients with rising prostate-specific antigen (PSA) after definitive therapy, normal testosterone and no radiographic metastasis were randomized to enzalutamide for 3 months with/without PROSTVAC for 6 months. Thereafter, patients could be retreated with another 3 month course of enzalutamide when PSA returned to baseline. Immune profiles were evaluated in these patients. RESULTS: Thirty-eight patients were randomized with a median PSA=4.38 ng/dL and PSA doubling time=4.1 months. No difference was observed between the two groups for PSA growth kinetics, but PSA responses to enzalutamide were noteworthy regardless of PROSTVAC. The median PSA decline after short-course enzalutamide without ADT/testosterone lowering therapy was 99% in both courses. The median time to PSA recovery to baseline after each 84-day course of enzalutamide was also noteworthy because of the duration of response after enzalutamide was discontinued. After the first and second 3 month cycle of enzalutamide, PSA recovery to baseline took a median 224 (range 84-1246) and 189 days (78-400), respectively. The most common adverse events related to the enzalutamide were grade 1 fatigue (71%) and grade 1 breast pain/nipple tenderness (81%). The only grade 3 toxicity was aspartate aminotransferase (AST)/alanine aminotransferase (ALT) elevation in two patients. Enzalutamide was independently associated with immune changes, increasing natural killer cells, naïve-T cells, and decreasing myeloid-derived suppressor cells. CONCLUSIONS: Three months of enzalutamide without ADT induced substantial PSA control beyond the treatment period and was repeatable, perhaps representing an alternative to intermittent ADT in nmCSPC. In addition, enzalutamide was associated with immune changes that could be relevant as future immune combinations are developed. TRAIL REGISTRATION NUMBER: clinicaltrials.gov (NCT01875250).

Phase 2 Study of Seviteronel (INO-464) in Patients With Metastatic Castration-Resistant Prostate Cancer After Enzalutamide Treatment.

BACKGROUND: Seviteronel was being developed by Innocrin Pharmaceuticals as a selective cytochrome P450c17a (CYP17) 17,20-lyase (lyase) inhibitor and androgen receptor antagonist with activity against prostate cancer cells in vitro and in vivo. This open-label phase 2 clinical study evaluated the tolerability and efficacy of seviteronel in patients with metastatic castration-resistant prostate cancer (mCRPC) previously treated with enzalutamide. PATIENTS AND METHODS: Patients with mCRPC whose disease previously progressed while receiving enzalutamide therapy were divided into 2 cohorts on the basis of prior exposure to docetaxel. Seviteronel was administered without routine oral steroids either twice daily with dose titration (450 mg) or once daily without dose titration (600 or 750 mg). The primary objective was to determine the rate of significant prostate-specific antigen response (ie, decline of ≥ 50%) after 12 weeks of seviteronel therapy. RESULTS: Seventeen patients, with a median (range) age of 71 (60-92) years, were enrolled, with 8 patients having received prior docetaxel. Patients received a median of 2 cycles of treatment, with most patients discontinuing treatment because of toxicity related to the study drug. The most common adverse events included concentration impairment, fatigue, tremor, and nausea. Despite changes in dosing, the study was closed prematurely because of the high magnitude of toxicity. One (6%) of 17 patients experienced a significant decline in prostate-specific antigen. CONCLUSION: Seviteronel was not generally well tolerated nor associated with significant clinical responses in patients with mCRPC who had previously received enzalutamide. Further investigation of single-agent seviteronel in this patient population is not warranted; however, studies investigating seviteronel with low-dose dexamethasone are ongoing in patients with androgen receptor-positive tumors.

Activity of durvalumab plus olaparib in metastatic castration-resistant prostate cancer in men with and without DNA damage repair mutations.

BACKGROUND: Checkpoint inhibitors have not been effective for prostate cancer as single agents. Durvalumab is a human IgG1-K monoclonal antibody that targets programmed death ligand 1 and is approved by the U.S. Food and Drug Administration for locally advanced or metastatic urothelial cancer and locally advanced, unresectable stage 3 non-small cell lung cancer. Olaparib, a poly (ADP-ribose) polymerase inhibitor, has demonstrated an improvement in median progression-free survival (PFS) in select patients with metastatic castration-resistant prostate cancer (mCRPC). Data from other trials suggest there may be improved activity in men with DNA damage repair (DDR) mutations treated with checkpoint inhibitors. This trial evaluated durvalumab and olaparib in patients with mCRPC with and without somatic or germline DDR mutations. METHODS: Eligible patients had received prior enzalutamide and/or abiraterone. Patients received durvalumab 1500 mg i.v. every 28 days and olaparib 300 mg tablets p.o. every 12 h until disease progression or unacceptable toxicity. All patients had biopsies of metastatic lesions with an evaluation for both germline and somatic mutations. RESULTS: Seventeen patients received durvalumab and olaparib. Nausea was the only nonhematologic grade 3 or 4 toxicity occurring in > 1 patient (2/17). No patients were taken off trial for toxicity. Median radiographic progression-free survival (rPFS) for all patients is 16.1 months (95% CI: 4.5-16.1 months) with a 12-month rPFS of 51.5% (95% CI: 25.7-72.3%). Activity is seen in patients with alterations in DDR genes, with a median rPFS of 16.1 months (95% CI: 7.8-18.1 months). Nine of 17 (53%) patients had a radiographic and/or PSA response. Patients with fewer peripheral myeloid-derived suppressor cells and with alterations in DDR genes were more likely to respond. Early changes in circulating tumor cell counts and in both innate and adaptive immune characteristics were associated with response. CONCLUSIONS: Durvalumab plus olaparib has acceptable toxicity, and the combination demonstrates efficacy, particularly in men with DDR abnormalities. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02484404 .

Topographic indications of emerging keratoconus in teenage New Zealanders.

PURPOSE: To screen a population of teenagers for emerging topographic signs of keratoconus (KC), with particular reference to ethnicity. METHODS: Corneal topography, visual acuity, and an environmental risk factor analysis were included in a screening program designed to identify early indications of potential KC in teenagers. Two schools from central North Island, New Zealand, were invited to participate: one with predominantly Maori/Polynesian students and the other with students of mainly European descent. RESULTS: A total of 198 Maori/Polynesian, 16.8 +/- 1.05 years of age, and 243 European students, 16.2 +/- 1.3 years of age, participated in the study. Corneal topography suggestive strongly of KC was evident in 3 Maori/Polynesian [1.2%; 95% confidence interval (CI): 0.3-4.3] and no European students (0%; 95% CI, 0%-1.5%). Anomalous corneal topography reminiscent of emerging KC in at least 1 eye were found in 19% (95% CI, 15.6%-22.9%). A significant difference (P = 0.0014) in the percentage of suspected KC was found between European students (12.9%; 95% CI, 9.2%-17.9%) and Maori/Polynesian students (26.9%; 95% CI, 21.0%-33.7%). In multivariate analyses, the significant independent predictors of probable or suspected KC included being Maori/Polynesian [odds ratio (OR) = 2.1; 95% CI, 1.25-3.54; P = 0.0052], increasing age (OR = 1.4; 95% CI, 1.10-1.80; P = 0.0067), and a history of hayfever (OR = 2.0; 95% CI, 1.16-3.59; P = 0.013). Topographical indicators that were associated significantly with suspected KC included central keratometry (P < 0.0001), astigmatism (P = 0.014), and inferior-superior asymmetry (P < 0.0001). CONCLUSIONS: Although only a longitudinal study will determine the proportion of true KC candidates, these data provide evidence of ethnicity-related differences in corneal topography in teenage New Zealanders.

Insulin and IGF1 signalling pathways in human astrocytes in vitro and in vivo; characterisation, subcellular localisation and modulation of the receptors.

BACKGROUND: The insulin/IGF1 signalling (IIS) pathways are involved in longevity regulation and are dysregulated in neurons in Alzheimer's disease (AD). We previously showed downregulation in IIS gene expression in astrocytes with AD-neuropathology progression, but IIS in astrocytes remains poorly understood. We therefore examined the IIS pathway in human astrocytes and developed models to reduce IIS at the level of the insulin or the IGF1 receptor (IGF1R). RESULTS: We determined IIS was present and functional in human astrocytes by immunoblotting and showed astrocytes express the insulin receptor (IR)-B isoform of Ir. Immunocytochemistry and cell fractionation followed by western blotting revealed the phosphorylation status of insulin receptor substrate (IRS1) affects its subcellular localisation. To validate IRS1 expression patterns observed in culture, expression of key pathway components was assessed on post-mortem AD and control tissue using immunohistochemistry. Insulin signalling was impaired in cultured astrocytes by treatment with insulin + fructose and resulted in decreased IR and Akt phosphorylation (pAkt S473). A monoclonal antibody against IGF1R (MAB391) induced degradation of IGF1R receptor with an associated decrease in downstream pAkt S473. Neither treatment affected cell growth or viability as measured by MTT and Cyquant® assays or GFAP immunoreactivity. DISCUSSION: IIS is functional in astrocytes. IR-B is expressed in astrocytes which differs from the pattern in neurons, and may be important in differential susceptibility of astrocytes and neurons to insulin resistance. The variable presence of IRS1 in the nucleus, dependent on phosphorylation pattern, suggests the function of signalling molecules is not confined to cytoplasmic cascades. Down-regulation of IR and IGF1R, achieved by insulin + fructose and monoclonal antibody treatments, results in decreased downstream signalling, though the lack of effect on viability suggests that astrocytes can compensate for changes in single pathways. Changes in signalling in astrocytes, as well as in neurons, may be important in ageing and neurodegeneration.

Accuracy of Orbscan II slit-scanning elevation topography.

PURPOSE: To establish the accuracy of Orbscan II (Orbtek Inc.) slit-scanning elevation topography in analyzing the anterior surface of complex test objects. SETTING: Discipline of Ophthalmology, University of Auckland, Faculty of Medical and Health Sciences, Auckland, New Zealand. METHODS: Six test objects were created from 2 materials: standard calibration poly(methyl methacrylate) (PMMA) (Orbtek Inc.) and a research PMMA material. The test objects were produced with spherical (radii of curvature 6.00 mm, 7.67 mm, and 8.88 mm), aspherical (apical radius 7.67, eccentricity 0.5, Q -0.25), and toroidal (7.67/7.92 mm radii of curvature) surfaces. The accuracy of the test surfaces was established by Form Talysurf Analysis. A single calibrated Orbscan II device was used to obtain 20 separate anterior elevation maps of each test object. The data obtained from Orbscan II, at 0.2 mm intervals along the chosen meridian, were directly compared with the Talysurf values for each test surface. RESULTS: Orbscan II measurements of all test objects were statistically significantly different from the Talysurf values (P <.001). The test objects produced from standard calibration material were more accurately measured by Orbscan II than the objects produced from the research material. Data obtained by Orbscan II from the central 3.5 mm of all test objects were more accurate than peripheral data when compared with the Talysurf values (P =.001). CONCLUSIONS: Orbscan II anterior surface elevation measurements differed significantly from Form Talysurf Analysis of complex test surfaces. However, the magnitude of the errors in the measurement of standard test objects was small, less than 0.20 microm centrally and 0.70 microm peripherally. Clinically, if similar accuracy of measurement is confirmed in the human eye, anterior surface elevation maps can be considered accurate representations of corneal shape.

A profile of keratoconus in New Zealand.

PURPOSE: To examine the characteristics and risk factors for keratoconus in a New Zealand population. METHODS: A one-page questionnaire was designed and sent to optometrists and ophthalmologists in New Zealand. Eye care practitioners then issued questionnaires to their keratoconic patients over a 6-month period. RESULTS: A total of 673 completed questionnaires were received from patients with keratoconus. A male bias (59%) was apparent in the sample. In line with previous work, a high proportion of the keratoconic cohort rubbed their eyes and suffered from atopy. A familial rate of 23.5% was evident, with several families reporting multiple keratoconus cases. Eleven pairs of twins were identified with at least one keratoconic sibling. Multivariate statistical analysis revealed significant independent correlations between the early development of keratoconus and gender, allergy, asthma, and latitude of childhood domicile. CONCLUSION: Results from the survey concur with a previous local report that keratoconus affects males more frequently and earlier in life than females in New Zealand. The concurrence of atopic disease and eye rubbing with keratoconus was as expected, and an association between the early development of the disease and latitude of the childhood domicile emerged. A strong familial component, exceeding previously reported figures, was evident in the cohort.

The Nepal Longitudinal Study: biometric characteristics of developing eyes.

PURPOSE: To identify differences in potential biometric markers for predicting refractive error in school children. METHODS: Biometric data on 895 Tibetan children, aged 6 to 18 years, residing in Katmandu, Nepal, were collected biennially from 1992 to 2000. Measurements included cycloplegic autorefraction, A-scan ultrasonography, and video phakometry. Only those children who had been studied at least once at age 12 years or more were included in the analysis. Subjects were divided into two groups: a myopia group if the refractive error was myopic by more than -0.50 D and a nonmyopia group if the refractive error was maximally myopic by -0.50 D, expressed as a spherical equivalent error in the left eye. RESULTS: Biometric measures that differed significantly with increasing age between the two refractive groups included: anterior chamber depth + 0.012 mm/year (p = 0.014), anterior lens radius of curvature + 0.073 mm/year (p = 0.001), lens power -0.059 D/year (p = 0.082), lens thickness -0.005 mm/year (p = 0.02), and vitreous chamber depth + 0.084 mm/year (p < 0.001). Corneal radii of curvature of the myopic group were steeper at all ages by 0.09 mm (p < 0.001), but the rate of change with age was equivalent across the refractive groups. CONCLUSIONS: Compared with those who remained nonmyopic, children who developed myopia had a crystalline lens that was initially thicker and steeper, and a vitreous chamber that was initially shorter. With age, children who became myopic developed greater lens thinning, greater flattening of the anterior lens surface radius, and a greater increase in vitreous chamber depth than their nonmyopic counterparts.

Effect of softperm lens wear on corneal thickness and topography: a comparison between keratoconic and normal corneae.

PURPOSE: Complications related to contact lens-induced anoxia in the keratoconic eye are well documented, but the underlying mechanisms are poorly understood. This study compared topographical changes in corneal thickness and anterior corneal radius following SoftPerm (Ciba Vision, Atlanta, GA) (rigid-and-soft combination) lens wear in a group of keratoconic and normal individuals. METHODS: Video keratoscopic (VKS) (EyeSys, Houston, TX) and ultrasonographic pachometry measurements were taken at nine ocular locations, at central, mid-peripheral, and peripheral corneal areas of keratoconic and normal subjects. Subjects were subsequently fitted with SoftPerm lenses and further measurements of corneal topography and thickness were noted after 1 day, 2 weeks, and 1 month of daily wear. RESULTS: Corneal thickness increased significantly in normal and keratoconic eyes following SoftPerm lens wear. Radius values obtained from the VKS measurements indicated that a significant and progressive degree of corneal flattening occurred for the keratoconic subjects at the 1-day, 2-week, and 1-month intervals, in contrast to the normal group, whose corneal radii remained unchanged. CONCLUSIONS: Corneal swelling occurs in both normal and keratoconic corneas following SoftPerm lens wear. Differences in the apparent central edema response within the keratoconic group may relate to the ease with which these corneas may be molded by a rigid contact lens.

The relationship between the sagitta of the anterior corneal surface and refractive error of the eye.

Changes in the sagitta of the anterior corneal surface associated with a change in the corneal radius of curvature have been used to calculate the change in refractive error of the eye in two areas: the ablation depth for laser surgery, and the change in corneal thickness associated with orthokeratology lens wear. An approximate formula known as Munnerlyn's formula is commonly used to calculate the refractive error change from sagittal data. This article compares the change in refraction calculated using the approximate formulae with the change calculated from a formula based on an elliptical corneal section. The approximate formula underestimates the ablation depth for a given refractive change and overestimates the refractive change for a given change in corneal thickness, assuming a constant asphericity. When the corneal asphericity increases together with an increase in radius of curvature, a suggested mechanism in orthokeratology, the approximate formula underestimates the change in ocular refraction.

Posterior corneal changes with orthokeratology.

PURPOSE: To investigate changes in corneal thickness and the radius of curvature of the posterior corneal surface after orthokeratology (OK) rigid lens wear. METHODS: Nineteen young myopic subjects wore reverse-geometry OK lenses (BE/ABE, Ultravision Contact Lenses, Brisbane, Australia) every night for 1 month. Central and midperipheral corneal thickness (Allergan Humphrey ultrasound, Carl Zeiss Meditec, Dublin, CA), topography (EyeSys v.3.1, Houston, TX), subjective refraction, and posterior corneal radii (video photography of Purkinje images) were evaluated within 2 h of waking, prelens wear, and on four occasions postlens wear during a 1-month period. A mixed-models approach was used to analyze the data. We modeled the changes in posterior corneal radius of curvature and corneal thickness in terms of the sagittal height of the anterior and posterior cornea using an ellipsoidal model for the corneal surfaces. RESULTS: Refractive error reduced from -2.28 to -0.01 DS within 1 month. A significant thinning of the cornea was evident between 1 (p = 0.03) and 2 weeks (p = 0.0048) postlens wear. A significant increase in the anterior corneal radius of curvature was present at all time periods beyond 1 night (p < 0.001), and a significant posterior corneal flattening occurred centrally and midperipherally after 1 week (p = 0.04 and p = 0.013, respectively). CONCLUSIONS: These findings suggest that in addition to the significant topographic flattening of the anterior corneal surfaces, there is also a significant flattening of the posterior surface during the early adaptive stages of OK lens wear.

Age dependence of ocular biometric measurements under cycloplegia with tropicamide and cyclopentolate.

BACKGROUND: Cyclopentolate continues to be the cycloplegic of choice for refracting young children, although many studies of ocular biometry promote the use of tropicamide. METHODS: To clarify the role of drug type in biometric measurements, cycloplegia was induced in two disparate age groups using cyclopentolate and tropicamide on two separate occasions. Refraction, phakometry and A-scan ultrasonography measurements were made on two groups of Tibetan children resident in Nepal. RESULTS: Cyclopentolate produced significantly more cycloplegia in the younger group, which was supported by phakometry measurements. However, in clinical terms, the difference between the measurements was not significant. CONCLUSION: We conclude that although cyclopentolate is more effective than tropicamide in relaxing accommodation in young children, the use of a local anaesthetic prior to instillation of tropicamide produces refractive data virtually equivalent to that of cyclopentolate, regardless of the age group measured. However, biometric measurements may be susceptible to greater error when near fixation targets are used during phakometry procedures.