Brain Tumors Research Today is a free monthly online journal that collates and summarizes the latest research about Brain Tumors, including details on symptoms, benign and malignant tumors, gliomas, screening, treatment. | ||||||||
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Heme oxygenase-1-mediated partial cytoprotective effect by NO on cadmium-induced cytotoxicity in C6 rat glioma cells.Srisook K, Jung NH, Kim BR, Cha SH, Kim HS, Cha YN Department of Pharmacology and Toxicology, College of Medicine, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 382-751, South Korea. Heme oxygenase-1 (HO-1) is a 32-kDa stress induced enzyme that degrades heme to carbon monoxide (CO) and biliverdin. By employing RT-PCR and Western blotting techniques, we have examined the HO-1 induction in C6 glioma cells that were treated with cadmium chloride (CdCl(2)) or spermine NONOate (SPER/NO). By employing a cell viability assay, we have also examined the cytoprotective effect of HO-1 induction against the cytotoxicity caused by toxic dose of CdCl(2). In C6 glioma cells exposed to CdCl(2), expression of HO-1 (mRNA and protein) was increased in a dose- and time-dependent manner. Nitric oxide (NO) generated from SPER/NO very rapidly increased HO-1 mRNA expression in the C6 glioma cells. The induction of HO-1 by SPER/NO protected the cells from toxic dose of CdCl(2). The up-regulation of HO-1 mRNA expression by CdCl(2) was inhibited by a pre-incubation of the cells with actinomycin D, a potent inhibitor of mRNA transcription. Upon the inhibition of elevated HO-1 mRNA expression by the use of zinc protoporphyrin IX (ZnPP), an inhibitor of HO activity, the change of HO-1 mRNA expression by ZnPP was not observed. Thus, the glial cell may respond to CdCl(2) toxicity by enhancing the HO-1 expression in its effort to minimize the CdCl(2)-derived oxidative damage, and to survive. In the glioma cells, when the HO-1 expression was elevated by a prior incubation with SPER/NO, the cell viability against the cytotoxicity of CdCl(2) was significantly increased. When the results of our experiment are taken together, we discovered that NO provided a rapid enhancement of HO-1 expression, and it provided a protective effect against CdCl(2)-derived oxidative injury in the C6 rat glioma cells. Published 7 December 2004 in Toxicol In Vitro, 19(1): 31-9.
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