Background and Purpose-Minocycline, a semisynthetic tetracycline antibiotic, has been reported to ameliorate brain injury and inhibit microglial activation after focal cerebral ischemia. However, the cerebroprotective mechanism of minocycline remains unclear. In the present study, we investigated that mechanism of minocycline in a murine model of 4-hour middle cerebral artery (MCA) occlusion. Methods-One day after 4-hour MCA occlusion, minocycline was administered intraperitoneally for 14 days. Neurologic scores were measured 1, 7, and 14 days after cerebral ischemia. Motor coordination was evaluated at 14 days by the rota-rod test at 10 rpm. Activated microglia and high-mobility group box1 (HMGB1), a cytokine-like mediator, were also evaluated by immunostaining and Western blotting. In addition, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling immunostaining was carried out 14 days after cerebral ischemia. Results-Repeated treatment with minocycline (1, 5, and 10 mg/kg) for 14 days improved neurologic score, motor coordination on the rota-rod test, and survival in a dose-dependent manner. Minocycline decreased the expression of Iba1, a marker of activated microglia, as assessed by both immunostaining and Western blotting. Moreover, minocycline decreased the activation of microglia expressing HMGB1 within the brain and also decreased both brain and plasma HMGB1 levels. Additionally, minocycline significantly decreased the number of terminal deoxynucleotidyl transferasemediated dUTP nick end-labeling-positive cells and prevented ischemic brain atrophy 14 days after cerebral ischemia.
Conclusions-Our
We examined the neuroprotective mechanism of cannabidiol, non-psychoactive component of marijuana, on the infarction in a 4 h mouse middle cerebral artery (MCA) occlusion model in comparison with D 9 -tetrahydrocannabinol (D 9 -THC). Release of glutamate in the cortex was measured at 2 h after MCA occlusion. Myeloperoxidase (MPO) and cerebral blood flow were measured at 1 h after reperfusion. In addition, infarct size and MPO were determined at 24 and 72 h after MCA occlusion. The neuroprotective effect of cannabidiol was not inhibited by either SR141716 or AM630. Both pre-and postischemic treatment with cannabidiol resulted in potent and long-lasting neuroprotection, whereas only pre-ischemic treatment with D 9 -THC reduced the infarction. Unlike D 9 -THC, cannabidiol did not affect the excess release of glutamate in the cortex after occlusion. Cannabidiol suppressed the decrease in cerebral blood flow by the failure of cerebral microcirculation after reperfusion and inhibited MPO activity in neutrophils. Furthermore, the number of MPO-immunopositive cells was reduced in the ipsilateral hemisphere in cannabidioltreated group. Cannbidiol provides potent and long-lasting neuroprotection through an anti-inflammatory CB 1 receptorindependent mechanism, suggesting that cannabidiol will have a palliative action and open new therapeutic possibilities for treating cerebrovascular disorders. Keywords: cannabidiol, cannabinoid, cerebral blood flow, cerebral ischemia, glutamate, myeloperoxidase. Cannabis contains about 60 different cannabinoids, including the psychoactive component D 9 -tetrahydrocannabinol (D 9 -THC) and other major non-psychoactive components such as cannabidiol, cannabinol, and cannabigerol. D 9 -THC has been demonstrated to produce hypothermia, neuroprotection, and tolerance (Hampson et al. 2000;Rubino et al. 2000;Wiley and Martin 2002;Braida et al. 2003;Leker et al. 2003;Hayakawa et al. 2004;Mishima et al. 2005). These effects are, at least in part, related to binding to the CB 1 receptor. On the other hand, cannabidiol has a very low affinity (in the micromolar range) for CB 1 and CB 2 receptors and has been found to act as an anticonvulsant in animal models of epilepsy and in humans with epilepsy. Moreover, cannabidiol has been shown to have antispasmodic, anxiolytic, anti-nausea, and anti-rheumatoid properties
Oral squamous cell carcinoma (OSCC) constitutes over 90% of all cancers in the oral cavity. The prognosis for patients with invasive OSCC is poor; therefore, it is important to understand the molecular mechanisms of invasion and subsequent metastasis not only to prevent cancer progression but also to detect new therapeutic targets against OSCC. Recently, extracellular vesicles-particularly exosomes-have been recognized as intercellular communicators in the tumor microenvironment. As exosomic cargo, deregulated microRNAs (miRNAs) can shape the surrounding microenvironment in a cancer-dependent manner. Previous studies have shown inconsistent results regarding miR-200c-3p expression levels in OSCC cell lines, tissues, or serum-likely because of the heterogeneous characters of the specimen materials. For this reason, single-cell clone analyses are necessary to effectively assess the role of exosome-derived miRNAs on cells within the tumor microenvironment. The present study utilized integrated microarray profiling to compare exosome-derived miRNA and exosome-treated cell-derived mRNA expression. Data were acquired from noninvasive SQUU-A and highly invasive SQUU-B tongue cancer cell clones derived from a single patient to determine candidate miRNAs that promote OSCC invasion. Matrigel invasion assays confirmed that hsa-miR-200c-3p was a key pro-invasion factor among six miRNA candidates. Consistently, silencing of the miR-200c-3p targets, CHD9 and WRN, significantly accelerated the invasive potential of SQUU-A cells. Thus, our data indicate that miR-200c-3p in exosomes derived from a highly invasive OSCC line can induce a similar phenotype in non-invasive counterparts.
A real-time cell-monitoring analysis (RTCA) system was previously developed based on the change in impedance when cells attach and spread in a culture dish coated with a gold microelectrode array. However, the potential applications of this system have not yet been fully demonstrated. The purpose of this study was to test the utility of the RTCA system to determine the cytotoxicity of four anticancer agents in carcinoma cells. The results were compared with those of the conventional WST-8 assay at the endpoint to determine the potential of the RTCA system as a new real-time assay method to evaluate cytotoxicity. iCELLigence was used as the RTCA system in this study. Suspensions of oral squamous cell carcinoma (OSCC) cell lines were seeded (2x10 4 cells/well) onto the E-plate (the culture plate of the iCELLigence system). After 24 h of culture, anticancer agents were added to each well, and changes in electrical impedance (cell index, CI) were recorded for another 72 h of culture. Cell proliferation was detected in real-time by the RTCA device in an automated, high throughput manner. Then, the IC 50 profiles of the four anticancer agents were calculated based on the real-time cell index values. The results indicated that the RTCA system was useful in evaluating cytotoxic reactions immediately after the addition of the anticancer agents as it was able to record the data in real-time. Furthermore, the IC 50 levels measured by the real-time assay were lower than those measured by the endpoint assay. Thus, RTCA systems can be used to evaluate chemotherapeutic agents in cancer cells as well as their side effects in normal cells.
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