Malignant gliomas are resistant to various proapoptotic therapies, such as radiotherapy and conventional chemotherapy. In this study, we show that selenite is preferentially cytotoxic to various human glioma cells over normal astrocytes via autophagic cell death. Overexpression of Akt, survivin, XIAP, Bcl-2, or Bcl-xL failed to block selenite-induced cell death, suggesting that selenite treatment may offer a potential therapeutic strategy against malignant gliomas with apoptotic defects. Before selenite-induced cell death in glioma cells, disruption of the mitochondrial cristae, loss of mitochondrial membrane potential, and subsequent entrapment of disorganized mitochondria within autophagosomes or autophagolysosomes along with degradation of mitochondrial proteins were noted, showing that selenite induces autophagy in which mitochondria serve as the main target. At the early phase of selenite treatment, high levels of superoxide anion were generated and overexpression of copper/zinc superoxide dismutase or manganese superoxide dismutase, but not catalase, significantly blocked seleniteinduced mitochondrial damage and subsequent autophagic cell death. Furthermore, treatment with diquat, a superoxide generator, induced autophagic cell death in glioma cells. Taken together, our study clearly shows that superoxide anion generated by selenite triggers mitochondrial damage and subsequent mitophagy, leading to irreversible cell death in glioma cells. [Cancer Res 2007;67(13):6314-24]

Background and Purpose-Astrocytic glutamate transporter protein, GLT-1 (EAAT2), recovers extracellular glutamate and ensures that neurons are protected from excess stimulation. Recently, ␤-lactam antibiotics, like ceftriaxone (CTX), were reported to induce the upregulation of GLT-1. Here, we investigated ischemic tolerance induction by CTX in an experimental model of focal cerebral ischemia. Methods-CTX (200 mg/kg per day, IP) was administered for 5 consecutive days before transient focal ischemia, which was induced by intraluminal thread occlusion of the middle cerebral artery for 90 minutes or permanently. Results-Repeated CTX injections enhanced GLT-1 mRNA and protein expressions after 3 and 5 days of treatment, respectively. CTX-pretreated animals showed a reduction in infarct volume by 58% (reperfusion) and 39% (permanent), compared with the vehicle-pretreated animals at 24 hours postischemia (PϽ0.01). Lower doses of CTX (20 mg/kg per day and 100 mg/kg per day) reduced infarct volumes to a lesser degree. The injection of GLT-1 inhibitor (dihydrokainate) at 30 minutes before ischemia ameliorated the effect of CTX pretreatment. However, CTX administration at 30 minutes after ischemia produced no significant reduction in infarct volume. CTX reduced the levels of proinflammatory cytokines (tumor necrosis factor-␣, FasL), matrix metalloproteinase (MMP)-9, and activated caspase-9 (PϽ0.01). In addition, CTX-pretreated animals showed better functional recovery at day 1 to week 5 after ischemia (PϽ0.05). Conclusions-This study presents evidence that CTX induces ischemic tolerance in focal cerebral ischemia and that this is mediated by GLT-1 upregulation. (Stroke. 2007;38:177-182.)

Sulforaphane is a chemopreventive agent present in various cruciferous vegetables, including broccoli. Here, we show that treatment with tumor necrosis factor (TNF)-related apoptosisinducing ligand (TRAIL) in combination with subtoxic doses of sulforaphane significantly induces rapid apoptosis in TRAIL-resistant hepatoma cells. Neither TNF-A-nor Fasmediated apoptosis was sensitized in hepatoma cells by cotreatment with sulforaphane, suggesting that sulforaphane can selectively sensitize cells to TRAIL-induced apoptosis but not to apoptosis mediated by other death receptors. We found that sulforaphane treatment significantly up-regulated mRNA and protein levels of DR5, a death receptor of TRAIL. This was accompanied by an increase in the generation of reactive oxygen species (ROS). Pretreatment with N-acetyl-Lcysteine and overexpression of catalase inhibited sulforaphane-induced up-regulation of DR5 and almost completely blocked the cotreatment-induced apoptosis. Furthermore, the sulforaphane-mediated sensitization to TRAIL was efficiently reduced by administration of a blocking antibody or small interfering RNAs for DR5. These results collectively indicate that sulforaphane-induced generation of ROS and the subsequent up-regulation of DR5 are critical for triggering and amplifying TRAIL-induced apoptotic signaling. We also found that sulforaphane can sensitize both Bcl-xL-and Bcl-2-overexpressing hepatoma cells to TRAIL-induced apoptosis, indicating that treatment with a combination of TRAIL and sulforaphane may be a safe strategy for treating resistant hepatomas. (Cancer Res 2006; 66(3): 1740-50)

No abstract

Erythropoietin (EPO), a pleiotropic cytokine involved in erythropoiesis, is tissue-protective in ischemic, traumatic, toxic and inflammatory injuries. In this study, we investigated the effect of EPO in experimental intracerebral hemorrhage (ICH). Two hours after inducing ICH via the stereotaxic infusion of collagenase, recombinant human EPO (500 or 5000 IU/kg, ICH + EPO group) or PBS (ICH + vehicle group) was administered intraperitoneally, then once daily afterwards for 1 or 3 days. ICH + EPO showed the better functional recovery in both rotarod and modified limb placing tests. The brain water content was decreased in ICH + EPO dose-dependently, as compared with ICH + vehicle. The effect of EPO on the brain water content was inhibited by N(omega)-Nitro-Larginine methyl ester hydrochloride (L-NAME, 10 mg/kg).Mean hemorrhage volume was also decreased in ICH + EPO. EPO reduced the numbers of TUNEL +, myeloperoxidase + or OX-42 + cells in the perihematomal area. In addition, EPO reduced the mRNA level of TNF-a, Fas and Fas-L, as well as the activities of caspase-8, 9 and 3. EPO treatment showed up-regulations of endothelial nitric oxide synthase (eNOS) and p-eNOS, pAkt, pSTAT3 and pERK levels. These data suggests that EPO treatment in ICH induces better functional recovery with reducing perihematomal inflammation and apoptosis, coupled with activations of eNOS, STAT3 and ERK. Keywords: apoptosis, endothelial nitric oxide synthase, extracellular signal-regulated kinase, erythropoietin, inflammation, intracerebral hemorrhage, STAT3. J. Neurochem. (2006Neurochem. ( ) 96, 1728Neurochem. ( -1739 Intracerebral hemorrhage (ICH) represents 15% of all strokes in Western populations and a higher proportion (20-30%) in Asian and black populations, and is the least treatable form of stroke with high mortality and morbidity (Qureshi et al. 2001). Nevertheless, supportive care or invasive neurosurgical evacuation of hematoma in selective patients is all that can be done (Mendelow et al. 2005). However, a controlled trial indicates that ICH patients show no overall benefit from early surgery when compared with medical treatment (Mendelow et al. 2005 These authors contributed equally to this study.Abbreviations used: EPO, erythropoietin; ICH, intracerebral hemorrhage; TUNEL, terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling; MPO, myeloperoxidase, STAT, signal transducers and activators of transcription; NOS, nitric oxide synthase; TNF, tumor necrosis factor; MLPT, modified limb placing test; BDNF, brainderived neurotrophic factor; ROS, reactive oxygen species; MCP-1, monocyte chemoattractant protein-1; MAPK, mitogen-activated protein kinase; PI3K, phosphatidylinositol 3-kinase; NFjB, nuclear factor-b; JAK-2, Janus kinase-2; L-NAME, N(omega)-Nitro-L-arginine methyl ester hydrochloride; ERK, extracellular signal-regulated kinase.Journal of Neurochemistry, 2006Neurochemistry, , 96, 1728Neurochemistry, -1739Neurochemistry, doi:10.1111Neurochemistry, /j.1471Neurochemistry, -4159.2006 (Broderick e...

No abstract

Dairy cattle are a primary reservoir of Coxiella burnetii, which causes Q fever. However, no recent nationwide studies have assessed the prevalence and risks of Q fever in dairy cattle. We report ≥94% prevalence in samples of bulk tank milk from U.S. dairy herds tested during the past 3 years.

Silibinin, a flavonoid isolated from Silybum marianum, has been reported to have cancer chemopreventive and therapeutic effects. Here, we show that treatment with subtoxic doses of silibinin in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces rapid apoptosis in TRAIL-resistant glioma cells, but not in human astrocytes, suggesting that this combined treatment may offer an attractive strategy for safely treating gliomas. Although the proteolytic processing of procaspase-3 by TRAIL was partially blocked in glioma cells, cotreatment with silibinin efficiently recovered TRAIL-induced caspase activation in these cells. Silibinin treatment up-regulated DR5, a death receptor of TRAIL, in a transcription factor CHOP-dependent manner. Furthermore, treatment with silibinin down-regulated the protein levels of the antiapoptotic proteins FLIP L , FLIP S , and survivin through proteasome-mediated degradation. Taken together, our results show that the activity of silibinin to modulate multiple components in the death receptormediated apoptotic pathway is responsible for its ability to recover TRAIL sensitivity in TRAIL-resistant glioma cells.