Death-Associated Protein Kinase 1 as a Promising Drug Target in Cancer and Alzheimer's Disease.

BACKGROUND: Death-Associated Protein Kinase 1 (DAPK1) plays an important role in apoptosis, tumor suppression and neurodegeneration including Alzheimer's Disease (AD). OBJECTIVE: This review will describe the diverse roles of DAPK1 in the development of cancer and AD, and the current status of drug development targeting DAPK1-based therapies. METHODS: Reports of DAPK1 regulation, function and substrates were analyzed using genetic DAPK1 manipulation and chemical DAPK1 modulators. RESULTS: DAPK1 expression and activity are deregulated in cancer and AD. It is down-regulated and/or inactivated by multiple mechanisms in many human cancers, and elicits a protective effect to counteract numerous death stimuli in cancer, including activation of the master regulator Pin1. Moreover, loss of DAPK1 expression has correlated strongly with tumor recurrence and metastasis, suggesting that lack of sufficient functional DAPK1 might contribute to cancer. In contrast, DAPK1 is highly expressed in the brains of most human AD patients and has been identified as one of the genetic factors affecting susceptibility to late-onset AD. The absence of DAPK1 promotes efficient learning and better memory in mice and prevents the development of AD by acting on many key proteins including Pin1 and its downstream targets tau and APP. Recent patents show that DAPK1 modulation might be used to treat both cancer and AD. CONCLUSION: DAPK1 plays a critical role in diverse physiological processes and importantly, its deregulation is implicated in the pathogenesis of either cancer or AD. Therefore, manipulating DAPK1 activity and/or expression may be a promising therapeutic option for cancer or AD.

Stability Analysis of Neural Networks With Time-Varying Delay by Constructing Novel Lyapunov Functionals.

This paper presents two novel Lyapunov functionals for analyzing the stability of neural networks with time-varying delay. Based on our newly proposed Lyapunov functionals and a relaxed Wirtinger-based integral inequality, new stability criteria are derived in the form of linear matrix inequalities. A comprehensive comparison of results is given to illustrate the newly proposed stability criteria from both the conservative and computational complexity point of views.

Best Core Stabilization for Anticipatory Postural Adjustment and Falls in Hemiparetic Stroke.

OBJECTIVES: To compare the effects of conventional core stabilization and dynamic neuromuscular stabilization (DNS) on anticipatory postural adjustment (APA) time, balance performance, and fear of falls in chronic hemiparetic stroke. DESIGN: Two-group randomized controlled trial with pretest-posttest design. SETTING: Hospital rehabilitation center. PARTICIPANTS: Adults with chronic hemiparetic stroke (N=28). INTERVENTIONS: Participants were randomly divided into either conventional core stabilization (n=14) or DNS (n=14) groups. Both groups received a total of 20 sessions of conventional core stabilization or DNS training for 30 minutes per session 5 times a week during the 4-week period. MAIN OUTCOME MEASURES: Electromyography was used to measure the APA time for bilateral external oblique (EO), transverse abdominis (TrA)/internal oblique (IO), and erector spinae (ES) activation during rapid shoulder flexion. Trunk Impairment Scale (TIS), Berg Balance Scale (BBS), and Falls Efficacy Scale (FES) were used to measure trunk movement control, balance performance, and fear of falling. RESULTS: Baseline APA times were delayed and fear of falling was moderately high in both the conventional core stabilization and DNS groups. After the interventions, the APA times for EO, TrA/IO, and ES were shorter in the DNS group than in the conventional core stabilization group (P<.008). The BBS and TIS scores (P<.008) and the FES score (P<.003) were improved compared with baseline in both groups, but FES remained stable through the 2-year follow-up period only in the DNS group (P<.003). CONCLUSIONS: This is the first clinical evidence highlighting the importance of core stabilization exercises for improving APA control, balance, and fear of falls in individuals with hemiparetic stroke.

Kinetic analysis of de novo centriole assembly in heat-shocked mammalian cells.

Mammalian cells are capable of de novo centriole formation after the removal of existing centrioles. This suggests that de novo centriole assembly is repressed in normally duplicating cells to maintain a constant number of centrioles in the cells. However, neither the mechanism of de novo centriole assembly nor that of its hypothesized repression is understood due to the lack of an experimental system. We found that the heat shock (HS; 42°C, 2 h) of mouse embryonic fibroblasts caused the separation of centriole pairs, a transient increase in polo-like kinase (Plk) 4 expression, and the formation of a complex containing γ-tubulin, pericentrin, HS protein (Hsp) 90, and Plk4, in approximately half of the cells. Subsequently, spindle-assembly abnormal protein (Sas) 6, centrosomal protein (Cep) 135, and centrin localized to the complex, and tubulin consequently became polyglutamylated, indicating de novo centriole assembly in the heat-shocked cells. These results suggested that HS-induced de novo centriole assembly could provide an experimental system for further elucidating the regulation of centrosome number in mammalian cells. © 2016 Wiley Periodicals, Inc.

Extended dissipative analysis for neural networks with time-varying delays.

In this brief, an extended dissipativity analysis was conducted for a neural network with time-varying delays. The concept of the extended dissipativity can be used to solve for the H∞, L2-L∞, passive, and dissipative performance by adjusting the weighting matrices in a new performance index. In addition, the activation function dividing method is modified by introducing a tuning parameter. Examples are provided to show the effectiveness and less conservatism of the proposed method.

Stochastic sampled-data control for state estimation of time-varying delayed neural networks.

This study examines the state estimation problem for neural networks with a time-varying delay. Unlike other studies, the sampled-data with stochastic sampling is used to design the state estimator using a novel approach that divides the bounding of the activation function into two subintervals. To fully use the sawtooth structure characteristics of the sampling input delay, a discontinuous Lyapunov functional is proposed based on the extended Wirtinger inequality. The desired estimator gain can be characterized in terms of the solution to linear matrix inequalities (LMIs). Finally, the proposed method is applied to two numerical examples to show the effectiveness of our result.

UNC119a bridges the transmission of Fyn signals to Rab11, leading to the completion of cytokinesis.

Src family kinases (SFKs) regulate the completion of cytokinesis through signal transduction pathways that lead to the Rab11-dependent phosphorylation of ERK and its localization to the midbody of cytokinetic cells. We find that UNC119a, a known activator of SFKs, plays essential roles in this signaling pathway. UNC119a localizes to the centrosome in interphase cells and begins to translocate from the spindle pole to the spindle midzone after the onset of mitosis; it then localizes to the intercellular bridge in telophase cells and to the midbody in cytokinetic cells. We show that the midbody localization of UNC119a is dependent on Rab11, and that knocking down UNC119a inhibits the Rab11-dependent phosphorylation and midbody localization of ERK and cytokinesis. Moreover, we demonstrate that UNC119a interacts with a Src family kinase, Fyn and is required for the activation of this kinase. These results suggest that UNC119a plays a key role in the Fyn signal transduction pathway, which regulates the completion of cytokinesis via Rab11.

State estimation for genetic regulatory networks with mode-dependent leakage delays, time-varying delays, and Markovian jumping parameters.

This paper considers the state estimation problem for Markovian jumping genetic regulatory networks (GRNs) with mode-dependent leakage and time-varying delays. In order to approximate the true concentrations of the mRNA and protein, the state estimator is designed using available measurement outputs. The GRNs are composed of N modes. The system switches from one mode to another according to a Markovian chain with known transition probabilities. Based on the Lyapunov functionals, including triple integral terms, some inequalities, and a time-varying delay partitioning approach, delay-dependent criteria which employ all upper bounds of time delays of each mode are obtained in terms of linear matrix inequalities (LMIs). This guarantees that the estimation error dynamics can be globally asymptotically stable from solutions of LMIs. Finally, a numerical example is presented to demonstrate the efficiency of the proposed estimation scheme.

Oncogenic extracellular vesicles in brain tumor progression.

The brain is a frequent site of neoplastic growth, including both primary and metastatic tumors. The clinical intractability of many brain tumors and their distinct biology are implicitly linked to the unique microenvironment of the central nervous system (CNS) and cellular interactions within. Among the most intriguing forms of cellular interactions is that mediated by membrane-derived extracellular vesicles (EVs). Their biogenesis (vesiculation) and uptake by recipient cells serves as a unique mechanism of intercellular trafficking of complex biological messages including the exchange of molecules that cannot be released through classical secretory pathways, or that are prone to extracellular degradation. Tumor cells produce EVs containing molecular effectors of several cancer-related processes such as growth, invasion, drug resistance, angiogenesis, and coagulopathy. Notably, tumor-derived EVs (oncosomes) also contain oncogenic proteins, transcripts, DNA, and microRNA (miR). Uptake of this material may change properties of the recipient cells and impact the tumor microenvironment. Examples of transformation-related molecules found in the cargo of tumor-derived EVs include the oncogenic epidermal growth factor receptor (EGFRvIII), tumor suppressors (PTEN), and oncomirs (miR-520g). It is postulated that EVs circulating in blood or cerebrospinal fluid (CSF) of brain tumor patients may be used to decipher molecular features (mutations) of the underlying malignancy, reflect responses to therapy, or molecular subtypes of primary brain tumors [e.g., glioma or medulloblastoma (MB)]. It is possible that metastases to the brain may also emit EVs with clinically relevant oncogenic signatures. Thus, EVs emerge as a novel and functionally important vehicle of intercellular communication that can mediate multiple biological effects. In addition, they provide a unique platform to develop molecular biomarkers in brain malignancies.

A case of esophageal stricture after iodine 131 ablation.

OBJECTIVE: To report the first case of esophageal stricture as a complication of radioiodine (¹³¹I) ablation therapy. METHODS: We review the medical and surgical history of this patient and discuss various potential causes of the esophageal stricture. RESULTS: A 79-year-old woman presented with increasing dysphagia and weight loss of about 4.5 kg after recent ¹³¹I therapy for thyroid cancer remnant ablation. Her pertinent history included gastroesophageal reflux disease, an anterior midcervical esophageal web, and a distal esophageal stricture. She also had a history of radiation therapy to her chest for breast cancer about 28 years previously. On the day of ¹³¹I therapy, the 5.5-GBq ¹³¹I capsule lodged accidentally in her midcervical area for approximately 2.5 hours. The resulting radiation dose to the proximal esophagus was estimated to be 7.86 Gy from gamma radiation and possibly as high as several thousand grays from beta radiation. During this time, the esophagus had possible direct exposure to the sodium phosphate dibasic that was used as filler in the sodium iodide capsule. Because of the worsening dysphagia, an esophagogastroduodenoscopy was performed 4 weeks after the ¹³¹I therapy, which showed a new proximal esophageal stricture. CONCLUSION: We believe that the additional localized radiation and sodium phosphate exposure from the lodging of the ¹³¹I capsule may have contributed to the development of a proximal esophageal stricture. To our knowledge, such an occurrence has not previously been described in the medical literature. For prevention of such an occurrence, we recommend a careful swallowing evaluation of patients with any history of esophageal radiation exposure, dysphagia, or esophageal strictures before administration of ¹³¹I in capsule form. Alternative methods of ¹³¹I delivery, if available, should be considered.

A novel inhibitor of apoptosis protein (IAP)-interacting protein, Vestigial-like (Vgl)-4, counteracts apoptosis-inhibitory function of IAPs by nuclear sequestration.

The inhibitors of apoptosis proteins (IAP), which include cIAP1, cIAP2 and XIAP, suppress apoptosis through the inhibition of caspases, and the activity of IAPs is regulated by a variety of IAP-binding proteins. Herein, we report the identification of a Vestigial-like 4 (Vgl-4), which functions as a transcription cofactor in cardiac myocytes, as a new IAP binding protein. Vgl-4 is expressed predominantly in the nucleus and its overexpression triggers a relocalization of IAPs from the cytoplasm to the nucleus. cIAP1/2-interacting protein TRAF2 (TNF receptor-associated factor 2) prevented the Vgl-4-driven nuclear localization of cIAP2. Accordingly, the forced relocation of IAPs to the nucleus by Vgl-4 significantly reduced their ability to prevent Bax- and TNFα-induced apoptosis, which can be recovered by co-expression with TRAF2. Our results suggest that Vgl-4 may play a role in the apoptotic pathways by regulating translocation of IAPs between different cell compartments.

Dose-dependent pharmacokinetics of SP-8203 in rats.

The pharmacokinetics of SP-8203, a potential protective agent for the treatment of cerebral infarction, were evaluated after its intravenous (10, 20 and 30 mg/kg) and oral (10, 20, 30 and 100 mg/kg) administration in rats. After the intravenous administration of SP-8203, the AUCs of SP-8203 were dose-dependent; the dose-normalized AUCs were significantly greater with increasing doses. After the oral administration of SP-8203, plasma concentrations of SP-8203 were much lower than those after intravenous administration. This could be due to considerable hepatic and intestinal metabolism and the high percent of the dose recovered from the gastrointestinal tract (including its contents and feces) at 24 h as unchanged drug.

An electronic device for accelerating bone formation in tissues surrounding a dental implant.

A dental implant is a unique structure which can be used with a noninvasive method because it is inserted into the bone in part and extended extracorporally. This study presents an electronic device that is temporarily connected with the dental implant, and reports its effect on accelerating bone formation in the surrounding tissues in a canine mandibular model. A small sized and low power consumption biphasic electrical current (BEC) stimulator ASIC was developed and the surrounding tissue was exposed to continuous BEC stimulation for 7 days with the parameters of 20 microA/cm(2), 125 micros duration, and 100 pulses/s. After 2 (n = 5) and 5 weeks (n = 5), animals were sacrificed and the specimens were histomorphometrically evaluated. The newly formed bone area (BA) was 1.30 times (3 weeks, P < 0.05) and 1.35 times (5 weeks, P < 0.05) higher in the experimental group compared to the control group, respectively. Bone-implant contact (BIC) in 3-week specimens was 1.62 times (P < 0.05) greater in the experimental group, while there was no statistically significant difference in 5-week specimens. Based on these results showing accelerated bone formation on and around the dental implant, it could be suggested that the latent time for osseointegration in dental implants can be reduced, and the success rate of implants in poor quality bone can be increased by using our device with BEC.

cIAP1, cIAP2, and XIAP act cooperatively via nonredundant pathways to regulate genotoxic stress-induced nuclear factor-kappaB activation.

Various genotoxic agents cause monoubiquitination of NEMO/IKKgamma-the regulatory subunit of IkappaB kinase (IKK) complex-in the nucleus. Ubiquitinated NEMO exits from the nucleus and forms a complex with the IKK catalytic subunits IKKalpha and IKKbeta, resulting in IKK activation and, ultimately, nuclear factor-kappaB (NF-kappaB) activation. Thus, NEMO ubiquitination is a prerequisite for IKK-dependent activation of NF-kappaB. However, the IKK activation mechanism is unknown and the NEMO-ubiquitinating E3 enzyme has not been identified. We found that inhibitors of apoptosis protein (IAP) regulate genotoxic stress-induced NF-kappaB activation at different levels. XIAP mediates activation of the upstream IKK kinase, TAK1, and couples activated TAK1 to the IKK complex. This XIAP-dependent event occurs in response to camptotechin or etoposide/VP16; however, XIAP is dispensable for activation of NF-kappaB by doxorubicin, which engages a MEK-ERK pathway to activate IKK. We also show that cIAP1 mediates NEMO ubiquitination and cIAP2 regulates an event downstream of NEMO ubiquitination. Our study highlights nonredundant cooperative contributions of IAPs to antiapoptotic NF-kappaB activation by genotoxic signals beyond their classic caspase inhibitory functions.

Ubiquitination mediated by inhibitor of apoptosis proteins.

Inhibitor of apoptosis (IAP) proteins are a family of evolutionarily conserved proteins that regulate apoptosis as well as other cellular processes. The functions of many IAPs are defined by their RING domains, which possess E3 ubiquitin ligase activity and promote proteasomal degradation of an increasing number of target proteins. In this chapter, we describe the methods used in our laboratories to study the IAP's E3 activity.

Oxidative modification of peroxiredoxin is associated with drug-induced apoptotic signaling in experimental models of Parkinson disease.

The aim of this study was to investigate changes in protein profiles during the early phase of dopaminergic neuronal death using two-dimensional gel electrophoresis in conjunction with mass spectrometry. Several protein spots were identified whose expression was significantly altered following treatment of MN9D dopaminergic neuronal cells with 6-hydroxydopamine (6-OHDA). In particular, we detected oxidative modification of thioredoxin-dependent peroxidases (peroxiredoxins; PRX) in treated MN9D cells. Oxidative modification of PRX induced by 6-OHDA was blocked in the presence of N-acetylcysteine, suggesting that reactive oxygen species (ROS) generated by 6-OHDA induce oxidation of PRX. These findings were confirmed in primary cultures of mesencephalic neurons and in rat brain injected stereotaxically. Overexpression of PRX1 in MN9D cells (MN9D/PRX1) exerted neuroprotective effects against death induced by 6-OHDA through scavenging of ROS. Consequently, generation of both superoxide anion and hydrogen peroxide following 6-OHDA treatment was decreased in MN9D/PRX1. Furthermore, overexpression of PRX1 protected cells against 6-OHDA-induced activation of p38 MAPK and subsequent activation of caspase-3. In contrast, 6-OHDA-induced apoptotic death signals were enhanced by RNA interference-targeted reduction of PRX1 in MN9D cells. Taken together, our data suggest that the redox state of PRX may be intimately involved in 6-OHDA-induced dopaminergic neuronal cell death and also provide a molecular mechanism by which PRX1 exerts a protective role in experimental models of Parkinson disease.

Cell cycle-dependent expression of cIAP2 at G2/M phase contributes to survival during mitotic cell cycle arrest.

cIAP2 (cellular inhibitor of apoptosis protein 2) is induced by NF-kappaB (nuclear factor kappaB) when cells need to respond quickly to different apoptotic stimuli. A recent study using cDNA microarray technology has suggested that cIAP2 transcription is regulated in a cell cycle-dependent manner, although the mechanism for such regulation is unknown. In this study, we confirmed the cell cycle-dependent regulation of cIAP2 expression at both the mRNA and protein levels. Additionally, we found that a bipartite CDE (cell cycle-dependent element)/CHR (cell cycle gene homology region) element in the cIAP2 promoter mediates cIAP2 gene activation in G2/M phase. Cell cycle-dependent G2/M-phase-specific cIAP2 expression is enhanced by NF-kappaB activation, and selective down-regulation of cIAP2 causes cells blocked in mitosis with nocodazole to become susceptible to apoptosis, indicating that the G2/M-phase-specific expression of cIAP2 contributes to the survival of mitotically arrested cells. Our studies describing the NF-kappaB-independent G2/M-phase-specific expression of cIAP2 will help in further understanding the molecular basis of cIAP2 over-expression in a variety of human cancers.