No abstract available.
Buthionine Sulfoximine* ; Cell Line* ; Cisplatin* ; Humans* ; Lung Neoplasms* ; Lung* ; Stomach*

OBJECTIVES: To evaluate the effect of glutathione(GSH) on lead induced modulation of nitric oxide(NO) synthesis, and to examine how lead modulates NO production in macrophages. METHODS: This study was observed in a culture of RAW 264.7 cells, which originated from a tumor in a Balb/c mouse that was induced by the Abelson murine leukemia virus. The compounds investigated were lead chloride, N-acetyl-cystein(NAC), and Buthionine Sulfoximine(BSO). RESUJLTS: ATP synthesis in RAW 264.7 cells was unchanged by each lead concentration exposure in a dose dependent manner. The NO synthesis was decreased when exposed to lead(PbCl2) concentration 0.5 micro M. The presence of 300 micro M NAC, used as a pretreatment in the culture medium, caused the recovery of the lead induced decrease in NO synthesis, but in the presence of 300 micro M BSO as a pretreatment, there was no recoverey. Pretreatment with NAC and BSO had no affect on ATP synthesis at any of the lead concentrations used. CONCLUSIONS: These results indicated that GSH has a protective effect toward lead toxicity, and suggested that the inhibition of NO production in macrophage due to lead toxicity may be related to cofactors of iNOS (inducible nitric oxide synthase)
Abelson murine leukemia virus ; Acetylcysteine ; Adenosine Triphosphate ; Animals ; Buthionine Sulfoximine ; Glutathione* ; Macrophages ; Mice ; Nitric Oxide

OBJECTIVES: To evaluate the effect of glutathione(GSH) on lead induced modulation of nitric oxide(NO) synthesis, and to examine how lead modulates NO production in macrophages. METHODS: This study was observed in a culture of RAW 264.7 cells, which originated from a tumor in a Balb/c mouse that was induced by the Abelson murine leukemia virus. The compounds investigated were lead chloride, N-acetyl-cystein(NAC), and Buthionine Sulfoximine(BSO). RESUJLTS: ATP synthesis in RAW 264.7 cells was unchanged by each lead concentration exposure in a dose dependent manner. The NO synthesis was decreased when exposed to lead(PbCl2) concentration 0.5 micro M. The presence of 300 micro M NAC, used as a pretreatment in the culture medium, caused the recovery of the lead induced decrease in NO synthesis, but in the presence of 300 micro M BSO as a pretreatment, there was no recoverey. Pretreatment with NAC and BSO had no affect on ATP synthesis at any of the lead concentrations used. CONCLUSIONS: These results indicated that GSH has a protective effect toward lead toxicity, and suggested that the inhibition of NO production in macrophage due to lead toxicity may be related to cofactors of iNOS (inducible nitric oxide synthase)
Abelson murine leukemia virus ; Acetylcysteine ; Adenosine Triphosphate ; Animals ; Buthionine Sulfoximine ; Glutathione* ; Macrophages ; Mice ; Nitric Oxide

PURPOSE: Cycloporine A (CsA) is a immunosuppressive agent most widely used in organ transplanted patients for preventing immunorejection, but it has some side effects, including hypertension, nephrotoxicity, hepatotoxicity and diabetes. The mechanism of toxicity of CsA was not completely understood, but the reactive oxygen species has been proposed to be involved in the reaction of toxicity of CsA. The purpose of this study is to determine the effects of glutathione, as a physiological antioxidant on CsA induced cytotoxicity in rat insulinoma (RINm5F) cells. METHODS: RINm5F cells were incubated in the presence of CsA (105~108 M) and buthionine sulfoximine (BSO), as a inhibitor of r-glutamyl cysteine synthetase, was added to cultured media (RPMI1640). Twenty four hours of incubation with CsA and BSO, viable cells were determined by MTT method. RESULTS: CsA decreased cell viability in dose response in cultured RINm5F cells and significantly decreased according to redusing glutathione. CONCLUSION: These results suggested that CsA may induce the diabetes and glutathione have some roles in the pathogenesis of CsA-induced diabetes.
Animals ; Buthionine Sulfoximine ; Cell Survival ; Cyclosporine* ; Cysteine ; Glutathione* ; Humans ; Hypertension ; Insulinoma* ; Ligases ; Rats ; Reactive Oxygen Species

We examined the neurotoxic effects of 3 glutathione (GSH) depletors, buthionine sulfoximine (BSO), diethyl maleate (DEM) and phorone, under the presence of trolox, cycloheximide (CHX), pyrrolidine dithiocarbamate (PDTC) or MK-801 in primary mouse cortical cell cultures. All three depletors induced neuronal death in dose and exposure time dependent manner, and decreased total cellular GSH contents. The patterns of the neuronal death and the GSH decrements were dependent on the individual agents. DEM (200 micrometer) induced rapid and irreversible decrement of the GSH. BSO (1 mM) also decreased the GSH irreversibly but the rate of decrement was more progressive than that of DEM. Phorone (1 mM) reduced the GSH content to 40% by 4 hr exposure, that is comparable to the decrement of BSO, but the GSH recovered and reached over the control value by 36 hr exposure. BSO showed a minimal neurotoxicity (0-10%) at the end of 24 hr exposure, but marked neuronal cell death at the end of 48 hr exposure. The BSO (1 mM)-induced neurotoxicity was markedly inhibited by trolox or CHX and partially attenuated by MK-801. DEM induced dose-dependent cytotoxicity at the end of 24 hr exposure. Over the doses of 400 micrometer, glial toxicity also appeared. DEM (200 micrometer)-induced neurotoxicity was markedly inhibited by trolox or PDTC. Phorone (1 mM) induced moderate neurotoxicity (40%) at the end of 48 hr exposure. Only CHX showed significant inhibitory effect on the phorone-induced neurotoxicity. These results suggest that the GSH depletors induce neuronal injury via different mechanisms and that GSH depletors should be carefully employed in the researches of neuronal oxidative injuries.
Animals ; Buthionine Sulfoximine ; Cell Culture Techniques* ; Cell Death ; Cycloheximide ; Dizocilpine Maleate ; Glutathione* ; Mice* ; Neurons

This study was performed to evaluate in vitro cytotoxicity of chemotherapeutic agents in established human retinoblastoma cell line, Y79 and to study the possibility of enhancing the cytotoxicity of chemotherapeutic agents by administration of buthionine sulfoximine(BSO) which lowers the intracellular glutathione(GSH) level. IC50 defined as the concentration which inhibits the cell survival rates to 50% compared with control group was used to evaluate cytotoxicity. Intracellular level after 13.50 adminstration were measured and compared with the level prior to administration of BSO. Doxorubicin, cisplatin, and melphalan showed significant decrease of IC50 by administration of BSO(p<0.01). But vincristine did not show significant decrease of IC50 by administration of BSO(p>0.05). Intracellular GSH level prior to the administration of BSO was 0.931nM/mg protein. After the administration of BSO, they were lowered to 0.095nM/mg protein in both BSO concentrations. Results listed above suggest that cytotoxicity of doxorubicin, cisplatin, and melphalan can be enhanced by ESO. This effect may be mediated by decreased intracellualr level of GSH by BSO.
Buthionine Sulfoximine* ; Cell Line* ; Cell Survival ; Cisplatin ; Doxorubicin ; Drug Therapy ; Glutathione ; Humans ; Inhibitory Concentration 50 ; Melphalan ; Retinoblastoma* ; Vincristine

OBJECTIVE: The purpose of this study is to determine the effects of glutathione on cisplatin-induced cytotoxicity of human cervical carcinoma cell lines (SiHa: squamous cell carcinoma cell, CaSki: epidermoid metastatic carcinoma cell). METHODS: Human cervical carcinoma cells (SiHa, CaSki) were incubated with culture media (RPMI1640) in the presence of cisplatin and/or buthionine sulfoximine (BSO), as a inhibitor of gamma-glutamyl- cysteine synthetase, and/or glutathione (GSH) and/or 2-oxo 4-thiazolidine carboxylic acid (OTC). The viable cells were examined by using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and was determined by spectrophotometer at 570 nm. RESULTS: The incubation of cervical cells with cisplatin resulted in an decreasing cells viability by dose response. The MTT reduction rate were not different by BSO (5 mM) treatment in cervical cell lines. The viable cells were increased significantly by glutathione (5 mM) or OTC (5 mM) in cisplatin-treated cell lines. CONCLUSION: gamma-glutamylcysteine synthetase inhibitor had no effect on cisplatin toxicity. GSH and OTC had effect on cisplatin cytotoxicity. So, These result suggested that cervical cancer line cells were more susceptive to protective effects of glutathione and OTC than BSO on cisplatin induced-toxicity.
Buthionine Sulfoximine ; Carcinoma, Squamous Cell ; Cell Line* ; Cisplatin ; Culture Media ; Cysteine ; Glutathione* ; Humans* ; Ligases ; Uterine Cervical Neoplasms*

Retinal neurons are highly vulnerable to hypoxia/ischemia. Excitotoxicity and free radical injury have been proposed as the major mechanisms of ischemic retinal injury have been proposed as the major mechanisms of ischemic retinal neuronal death. In the present study, we examined these possibilities in retinal cultures. Exposure of these cultures to hypoxia for 48 hr induced selective death of neurons. Addition of an antioxidiant trolox markedly attenuated hypoxiainduced retinal neuronal death, whereas addition of glutamate antagonists, MK-801 or CNQX,did not. Morphologically, hypoxic neuronal death in cultures was accompanied by cell body swelling, a feature of necrosis, yet simultaneously exhibited some features of apoptosis such as TUNEL positivity and protection by cycloheximide. However, unlike in classical programmed cell death, adding buthionine sulfoximine, a potent inhibitor of glutathione synthesis, completely reversed the protective effect of cycloheximide. The results have demonstrated that free radical injury is the main mechanism of neuronal death in the present retinal culture, and suggest an intriguing possibility that free redical injury may become a prominent mechanism, when excitotoxic injury is masked.
Animals ; Anoxia ; Apoptosis ; Buthionine Sulfoximine ; Cell Death ; Cycloheximide ; Dizocilpine Maleate ; Excitatory Amino Acid Antagonists ; Glutathione ; In Situ Nick-End Labeling ; Masks ; Necrosis ; Neurons ; Rats* ; Retinal Neurons* ; Retinaldehyde*

Glutathione based detoxification system in tumor cells was proposed as one of the drug resistance mechanisms and appeared to play as an obstacle in anticancer chemotherapy. It was evaluated that depletion of glutathione content in MBT-2, murine bladder tumor cells by buthionine sulfoximine could enhance the chemotherapeutic effect of carboplatin. Glutathione contents were measured by an enzymatic assay and chemosensitivity was assessed by MTT colorimetric test. Twenty-four hours exposure to 1, 2.5, 5 and 10uM buthionine sulfoximine reduced intracellular glutathione levels to 84.9, 24.8, 18.3 and 11.0% of the control level, respectively, in MBT-2 tumor cell line. Pretreatment with 2.5, 5 and 10uM buthionine sulfoximine for 24 hours and continuous exposure to buthionine sulfoximine and carboplatin for 72 hours potentiated the carboplatin cytotoxicity by 1.26, 1.56 and 1.90 folds, respectively. The potentiation of antitumor effect of carboplatin in C3H/He mice MBT-2 tumor by buthionine sulfoximine was evaluated with the use of tumor growth and tumor volume-doubling time. Glutathione contents in the tumor and liver were reduced to 12.8 and 21.8% of the control level by oral administration of 30mM buthionine sulfoximine for 5 days. No significant change in serum creatinine levels and renal histology was found in the mice treated with buthionine sulfoximine. Combination of carboplatin and buthionine sulfoximine significantly reduced tumor growth rate and delayed tumor volume-doubling time compared to carboplatin alone(p <0.05), while buthionine sulfoximine alone did not influence the tumor growth(p >0.05). Weight loss or mortality due to carboplatin and buthionine sulfoximine administration was not noted. Since buthionine sulfoximine significantly enhanced the effect of carboplatin on murine bladder tumor without apparent toxicity, combination of buthionine sulfoximine and carboplatin could be a new strategy in chemotherapy against advanced bladder cancer.
Administration, Oral ; Animals ; Buthionine Sulfoximine* ; Carboplatin* ; Cell Line, Tumor ; Creatinine ; Drug Resistance ; Drug Therapy ; Enzyme Assays ; Glutathione ; Liver ; Mice ; Mortality ; Urinary Bladder Neoplasms* ; Urinary Bladder* ; Weight Loss

OBJECTIVETo investigate the apoptosis-induction, P-glycoprotein (P-gp) and mdr1 mRNA inhibition effects of arsenic trioxide (As2O3) and buthionine sulfoximine (BSO) on multidrug-resistant cell line K562/ADM cells, and to determine the relationship between intracellular GSH content and arsenic effect.

METHODSK562/ADM cells were treated with arsenic (0.5, 2.0, 5.0 micromol/L) alone or combined with BSO (100 micromol/L). The cell proliferating capacity was assessed with MTT assay, and cell apoptosis by Annexin V and propidium iodide (PI) staining. Intracellular GSH contents were measured using a glutathione assay kit by spectrophotometry. P-gp expression was determined by flow cytometry, and mdr1 mRNA expression by semi-quantitative RT-PCR.

RESULTSThe GSH contents in K562/ADM cell was (81.13 +/- 3.91) mg/g protein. After the GSH contents were degraded by BSO, the K562/ADM cell proliferating capacity was obviously inhibited and the cells were induced apoptosis in 24 hours by the combination of clinic dose arsenic group (0.5, 2.0 micromol/L) and BSO (100 micromol/L). The cell apoptosis rates at 48 hours in arsenic alone group and combination group were (59.29 +/- 6.01)% and (65.06 +/- 8.29)%, and at 72 hours were (82.15 +/- 9.28)% and (92.72 +/- 9.41)% retrospectively. At 48 hours, the mdr1 mRNA inhibition effect of the combination group was obviously stronger than that of high dose arsenic alone group. At 72 hours, the P-gp inhibition effect of the combination group (clinic dose arsenic group, 0.5, 2.0 micromol/L) was obviously stronger than that of high dose arsenic alone group (5.0 micromol/L).

CONCLUSIONThe intracellular GSH contents are closely correlated with the arsenic effect. The combination of conventional dose arsenic and BSO significantly induces K562/ADM cell apoptosis and inhibits P-gp and mdr1 mRNA expression in the cells.

ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; metabolism ; Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Buthionine Sulfoximine ; pharmacology ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Genes, MDR ; drug effects ; Glutathione ; metabolism ; Humans ; K562 Cells ; Oxides ; pharmacology