The detection and quantification of highly reactive oxygen species using the novel HPF fluorescence probe in a rat model of focal cerebral ischemia

A novel fluorescence probe, 2-[6-(4'-hydroxy) phenoxy-3H-xanthen-3-on-9-yl] benzoic acid (HPF) was used to investigate the generation of highly reactive oxygen species (hROS) under ischemia both in vitro and in vivo. In the in vitro study, HT 22 cells were used to demonstrate that was predominantly detected in the cytoplasm, which coincides with the location of the mitochondria and then its HPF fluorescence gradually increased from 6 to 24 h due to glutamate induced oxidative stress. In the in vivo study, the permanent and transient middle cerebral artery occlusion (MCAO) was induced in rats. Brain slices were incubated in an artificial medium containing HPF. The area of enhanced HPF fluorescence existed in both the ischemic core and the peri-infarct area at 4h after MCAO in both permanent and transient MCAO models. The area extended beyond the boundary of the ischemic damage into biochemically viable tissue. The enhanced fluorescent intensity following transient MCAO was higher than that observed in the permanent MCAO model. Hydroxyl radical scavenger, MCI-186 significantly suppressed the enhanced fluorescence intensity. This study demonstrated that HPF has a high sensitivity and specificity for the detection of hROS in focal cerebral ischemia as well as in a cellular model of oxidative stress.     

An examination of retrieval processes in implicit and explicit memory tests

The purpose of this study was to examine the retrieval processes in implicit and explicit memory tests by manipulating study tasks and test types. Ninety-six students wrote down target words embedded in the sentences and generated target words using 2-letter cues embedded in the sentences. Students in one test group were asked to recall the target words using the 2-letter cues and then recognize them from the words recalled. Students in the second group were asked to generate words using the 2-letter cues. Students in the third test group were asked to generate words using the 2-letter cues and then recognize the target words from the words generated. The results showed the generation effects in the cued recall test, but in the other test groups, there were no differences between the writing and the generation tasks. The results of the recognition test also showed the interaction between study task and test type. The results suggest that the targets generated are accessed differently between implicit and explicit memory tests.     

Thoracic intradural extramedullary lesions causing progressive myelopathy as an initial manifestation of granulomatosis with polyangiitis: a case report and review of literature

Context: To our knowledge, only a few reports regarding the spinal involvement of granulomatosis with polyangiitis (GPA)—also termed as Wegener's granulomatosis—have been published. However, all these cases reportedly exhibited epidural tumor-like lesions or dural thickening.

Findings: We report the case of a 57-year-old woman with progressive myelopathy caused by multiple spinal lesions with GPA, which appeared to be protruding inwards, within the dura mater, on magnetic resonance imaging (MRI); these lesions were difficult to distinguish from intradural tumors. Moreover, these lesions exhibited low intensity on both T1- and T2-weighted MRI, and showed prominent enhancement on gadolinium-contrast imaging. Resection biopsy was effective for both diagnosis and the recovery of the neurological deficit.

Conclusion: Based on these findings, we suggest that GPA lesions can exhibit variable patterns in the spine. Nevertheless, clinicians should consider the possibility of GPA in such cases, particularly when multiple, inwardly protruding tumor-like lesions are detected within the dura mater on MRI.     

Durable outcomes of thoracic endovascular aortic repair with Zenith TX1 and TX2 devices

Objective

Long-term data regarding the safety and durability of thoracic endovascular aortic repair (TEVAR) are limited. The study objective was to evaluate the long-term outcomes of TEVAR in high-risk patients with descending thoracic aortic pathology.

Immunostimulatory oncolytic activity of coxsackievirus A11 in human malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive solid cancer with a poor prognosis, whereas coxsackievirus A11 (CVA11) is a potential oncolytic virus for cancer treatment. We here investigated the oncolytic activity of CVA11 with human MPM cell lines. CVA11 infection was cytotoxic in all six MPM cell lines examined and showed no or minimal cytotoxicity toward normal human normal cell lines. MPM cells with a higher surface level of intercellular adhesion molecule-1 (ICAM-1) expression tended to be more susceptible to CVA11-induced cytotoxicity, and a neutralizing antibody to ICAM-1 attenuated such cytotoxicity. CVA11 infection activated signaling by Akt and extracellular signal-regulated kinase (ERK) pathways, and inhibitors of such signaling also abrogated CVA11-mediated cytotoxicity. Furthermore, CVA11 infection-triggered multiple modes of tumor cell death including apoptosis, pyroptosis, and necroptosis, and such death was accompanied by the release or exposure of the proinflammatory cytokine interleukin-1β and damage-associated molecular patterns such as calreticulin, high-mobility group box-1, annexin A1, and heat shock protein 70, which are hallmarks of immunogenic cell death. Notably, in vivo treatment of human MPM xenografts with intratumoral CVA11 injection resulted in significant suppression of tumor growth in SCID mice, and all mice infected with CVA11 showed no significant change in body weight. Our findings collectively suggest that the oncolytic activity of CVA11 for MPM is dependent on ICAM-1 as a virus receptor, as well as on Akt and ERK signaling, and that oncolytic virotherapy with CVA11 is a promising treatment modality with immunostimulatory activity for human MPM.     

Regulation of MEK inhibitor selumetinib sensitivity by AKT phosphorylation in the novel BRAF L525R mutant

Background

Oncogenic mutations in BRAF genes are found in approximately 5–10% of colorectal cancers. The majority of BRAF mutations are located within exons 11–15 of the catalytic kinase domains, with BRAF V600E accounting for more than 80% of the observed BRAF mutations. Sensitivity to BRAF- and mitogen-activated protein kinase (MEK) inhibitors varies depending on BRAF mutations and tumor cell types. Previously, we newly identified, BRAF L525R-mutation, in the activation segment of the kinase in colorectal cancer patient. Here, we characterized the function of the BRAF L525R mutation.

Methods

HEK293 cells harboring a BRAF mutation (V600E or L525R) were first characterized and then treated with cetuximab, dabrafenib, and selumetinib. Cell viability was measured using WST-1 assay and the expression of proteins involved in the extracellular signal-regulated kinase (ERK) and protein kinase B (AKT) signaling pathways was evaluated using western blot analysis.

Results

The MEK inhibitor selumetinib effectively inhibited cell proliferation and ERK phosphorylation in BRAF L525R cells but not in BRAF V600E cells. Further studies revealed that AKT phosphorylation was reduced by selumetinib in BRAF L525R cells but not in BRAF V600E cells or selumetinib-resistant BRAF L525R cells. Moreover, the AKT inhibitor overcame the selumetinib resistance.

Conclusions

We established a model system harboring BRAF L525R using HEK293 cells. BRAF L525R constitutively activated ERK. AKT phosphorylation caused sensitivity and resistance to selumetinib. Our results suggest that a comprehensive network analysis may provide insights to identify effective therapies.

     

Lactosome-Conjugated siRNA Nanoparticles for Photo-Enhanced Gene Silencing in Cancer Cells

The A₃B-type Lactosome comprised of poly(sarcosine)₃-block-poly(l-lactic acid), a biocompatible and biodegradable polymeric nanomicelle, was reported to accumulate in tumors in vivo via the enhanced permeability and retention (EPR) effect. Recently, the cellular uptake of Lactosome particles was enhanced through the incorporation of a cell-penetrating peptide (CPP), L7EB1. However, the ability of Lactosome as a drug delivery carrier has not been established. Herein, we have developed a method to conjugate the A₃B-type Lactosome with ATP-binding cassette transporter G2 (ABCG2) siRNA for inducing in vitro apoptosis in the cancer cell lines PANC-1 and NCI-H226. The L7EB1 peptide facilitates the cellular uptake efficiency of Lactosome but does not deliver siRNA into cytosol. To establish the photoinduced cytosolic dispersion of siRNA, a photosensitizer loaded L7EB1-Lactosome was prepared, and the photosensitizer 5,10,15,20-tetra-kis(pentafluorophenyl)porphyrin (TPFPP) showed superiority in photoinduced cytosolic dispersion. We exploited the combined effects of enhanced cellular uptake by L7EB1 and photoinduced endosomal escape by TPFPP to efficiently deliver ABCG2 siRNA into the cytosol for gene silencing. Moreover, the silencing of ABCG2, a protoporphyrin IX (PpIX) transporter, also mediated photoinduced cell death via 5-aminolevulinic acid (ALA)-mediated PpIX accumulated photodynamic therapy (PDT). The synergistic capability of the L7EB1/TPFPP/siRNA-Lactosome complex enabled both gene silencing and PDT.     

Early administration of amatuximab,a chimeric high-affinity anti-mesothelin monoclonal antibody,suppresses liver metastasis of mesothelin-expressing pancreatic cancer cells and enhances gemcitabine sensitivity in a xenograft mouse model

Investigational New Drugs - Amatuximab is a promising therapeutic antibody targeting mesothelin, a 40-kDa glycoprotein that is highly expressed in pancreatic cancer. We investigated the...