Purpose: Cancer cells can use X-linked inhibitor of apoptosis (XIAP) to evade apoptotic cues, including chemotherapy. The antitumor potential of AEG35156, a novel second-generation antisense oligonucleotide directed toward XIAP, was assessed in human cancer models when given as a single agent and in combination with clinically relevant chemotherapeutics. Experimental Design: AEG35156 was characterized for its ability to cause dose-dependent reductions of XIAP mRNA and protein in vitro and in vivo, to sensitize cancer cell lines to death stimuli, and to exhibit antitumor activity in multiple human cancer xenograft models as a single agent or in combination with chemotherapy. Results: AEG35156 reduced XIAP mRNA levels with an EC 50 of 8 to 32 nmol/L and decreased XIAP protein levels by >80%. Loss of XIAP protein correlated with increased sensitization to tumor necrosis factor^related apoptosis-inducing ligand (TRAIL)^mediated apoptosis in Panc-1 pancreatic carcinoma cells. AEG35156 exhibited potent antitumor activity relative to control oligonucleotides in three human cancer xenograft models (prostate, colon, and lung) and was capable of inducing complete tumor regression when combined with taxanes. Antitumor effects of AEG35156 correlated with suppression of tumor XIAP levels. Conclusions: AEG35156 reduces XIAP levels and sensitizes tumors to chemotherapy. AEG35156 is presently under clinical assessment in multiple phase I trials in cancer patients as a single agent and in combination with docetaxel in solid tumors or cytarabine/idarubicin in leukemia.Chemotherapy is the mainstay of clinical treatment for many solid tumors. However, the development of chemoresistance is a common feature, resulting in a decrease or loss of therapeutic effectiveness. One of the major mechanisms responsible for chemoresistance is the loss of apoptotic sensitivity in cancer cells. Possible causes include alterations in the initiation or execution of the apoptotic machinery, which results from increased activity of antiapoptotic proteins. Novel anticancer therapies that specifically target antiapoptotic mechanisms or that act to lower the apoptotic threshold of cancer cells are in preclinical development or under clinical evaluation (1). An appealing therapeutic candidate target is the X-linked inhibitor of apoptosis (XIAP), a potent antiapoptotic protein whose overexpression and dysfunction is associated with resistance to chemotherapy and radiotherapy (2 -5).Although apoptotic pathways in cells are complex, most seem to converge on a single family of proteases, the caspases that dismantle the cell in an orderly, noninflammatory fashion. The human IAP family, characterized by the presence of one to three baculovirus IAP repeat motifs at the NH 2 terminus of the polypeptide chain (reviewed in refs. 3, 6), are the only known cellular inhibitors of caspases. Specifically, they inhibit two key effector caspases, caspase-3 and caspase-7, and the key initiator caspase, caspase-9, which is responsible for the intrinsic mitochondria...

In vitro toxicological studies for tobacco product assessment have traditionally been undertaken using the particulate phase of tobacco smoke. However, this does not truly reflect exposure conditions that occur in smokers. Thus in vitro cell culture systems are required in which cells are exposed to tobacco whole smoke (WS) at the air-liquid interface (ALI). In this study bronchial epithelial cells were cultured on semi-permeable membranes, transitioned to the ALI and the robustness and sensitivity of the cells to tobacco WS and vapour phase (VP) assessed. Although no effect of air exposure was observed on cell viability, IL-6 and IL-8 release was increased. Exposure to WS resulted in a significant dose dependent decrease in cell viability and a significant non-dose dependent increase in inflammatory mediator secretion. The VP was found to contribute approximately 90% of the total cytotoxicity derived from WS. The cell culture system was also able to differentiate between two smoking regimens and was sensitive to passage number with increased inflammatory mediator secretion and lower cell viability observed in cell cultures of low passage number following WS exposure. This simple cell culture system may facilitate studies on the toxicological impact of future tobacco products and nicotine delivery devices.

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NMDA receptor antagonists, such as (ϩ)-5-methyl-10,11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine maleate (MK-801), potently block glutamate-induced neuronal death in myriad in vitro cell models and effectively attenuate ischemic damage in vivo. In this report, a novel role for MK-801 and other NMDA receptor antagonists in preconditioning neurons to withstand a wide range of subsequent lethal insults is described. A brief 30 min exposure to 0.1 M MK-801, applied up to 96 hr before a "lethal" insult, protected primary cortical neurons from a diverse group of neurotoxic agents, including NMDA, ␤-amyloid, staurosporine, etoposide, and oxygen-glucose deprivation. This neuroprotective preconditioning by MK-801 arose from transient NMDA receptor inactivation, because the noncompetitive NMDA receptor antagonists memantine and nylindin and the competitive antagonist AP-5 gave similar effects. MK-801 protection was dependent on new protein synthesis during the first 2 hr, but not from 2 to 5 hr, after MK-801 exposure. The MK-801 transient did not alter the ability of NMDA to trigger normally lethal [Ca 2ϩ ] i influx 48 hr later, but it did block early downstream signaling events coupled to NMDA neurotoxicity, including PKC inactivation and the activation of calpain. Moreover, MK-801 protected neurons from staurosporine-induced apoptosis, although caspase activation in these cells was unimpeded. It is likely that the stress associated with transient inactivation of NMDA receptors triggered a rapid compensatory survival response that provided long-term protection from a spectrum of insults, inducing apoptotic and nonapoptotic death. The possibility that MK-801 preconditioning blocks an event common to seemingly diverse death mechanisms suggests it will be an important tool for obtaining a clearer understanding of the salient molecular events at work in neuronal death and survival pathways.

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BackgroundDigital pathology (DP) has the potential to fundamentally change the way that histopathology is practised, by streamlining the workflow, increasing efficiency, improving diagnostic accuracy and facilitating the platform for implementation of artificial intelligence–based computer-assisted diagnostics. Although the barriers to wider adoption of DP have been multifactorial, limited evidence of reliability has been a significant contributor. A meta-analysis to demonstrate the combined accuracy and reliability of DP is still lacking in the literature.ObjectivesWe aimed to review the published literature on the diagnostic use of DP and to synthesise a statistically pooled evidence on safety and reliability of DP for routine diagnosis (primary and secondary) in the context of validation process.MethodsA comprehensive literature search was conducted through PubMed, Medline, EMBASE, Cochrane Library and Google Scholar for studies published between 2013 and August 2019. The search protocol identified all studies comparing DP with light microscopy (LM) reporting for diagnostic purposes, predominantly including H&E-stained slides. Random-effects meta-analysis was used to pool evidence from the studies.ResultsTwenty-five studies were deemed eligible to be included in the review which examined a total of 10 410 histology samples (average sample size 176). For overall concordance (clinical concordance), the agreement percentage was 98.3% (95% CI 97.4 to 98.9) across 24 studies. A total of 546 major discordances were reported across 25 studies. Over half (57%) of these were related to assessment of nuclear atypia, grading of dysplasia and malignancy. These were followed by challenging diagnoses (26%) and identification of small objects (16%).ConclusionThe results of this meta-analysis indicate equivalent performance of DP in comparison with LM for routine diagnosis. Furthermore, the results provide valuable information concerning the areas of diagnostic discrepancy which may warrant particular attention in the transition to DP.

Several lines of evidence indicate that a rapid loss of neuronal protein kinase C (PKC) activity is a characteristic feature of cerebral ischemia and is a necessary step in the NMDA-induced death of cultured neurons. Exposing embryonic day 18 primary rat cortical neurons to 50 M NMDA or 50 M glutamate for 10 min caused ϳ80% cell death over the next 24 h, but excitotoxic death was largely averted, i.e., by 70 -80%, in cells pretreated with brain-derived neurotrophic factor (BDNF). An 8-h preexposure to BDNF (50 -100 ng/ml) maximally protected cortical cells from the effects of NMDA and glutamate, although the transient application of BDNF between 8 and 4 h before NMDA was equally protective. These effects of BDNF were abolished at supralethal, i.e., Ͼ100 M, NMDA concentrations. It is significant that BDNF pretreatment prevented the inactivation of PKC in cortical cells normally seen 30 min to 2 h following lethal NMDA or glutamate exposure. This BDNF effect did not arise from changes in NMDA channel activity because neither whole-cell NMDA current amplitudes nor increases in intracellular free Ca 2ϩ concentration were altered by the 8-h BDNF pretreatment. Furthermore, BDNF offered no neuroprotection to cells treated with the PKC inhibitors staurosporine (10 -20 nM), calphostin C (1-2.5 M), or GF-109203X (100 nM) at the time of NMDA addition. These results underscore the importance of PKC inactivation in glutamate-induced neuronal death. They also suggest that BDNF neuroprotection arises, at least in part, via its ability to block the mechanism by which pathophysiological Ca 2ϩ influx through the NMDA receptor causes membrane PKC inactivation. Key Words: Glutamate toxicity-Protein kinase C-Brain-derived neurotrophic factor-Cortical cultures.