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1.
Leukemia ; 29(7): 1485-95, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25736236

ABSTRACT

In this study, we investigated the role of inositol polyphosphate-4-phosphatase, type-II (INPP4B) in acute myeloid leukemia (AML). We observed that AML patients with high levels of INPP4B (INPP4B(high)) had poor response to induction therapy, shorter event-free survival and shorter overall survival. Multivariate analyses demonstrated that INPP4B(high) was an independent predictor of poor prognosis, significantly improving current predictive models, where it outperformed conventional biomarkers including FLT3-ITD and NPM1. Furthermore, INPP4B(high) effectively segregated relative risk in AML patients with normal cytogenetics. The role of INPP4B on the biology of leukemic cells was assessed in vitro. Overexpression of INPP4B in AML cell lines enhanced colony formation potential, recapitulated the chemotherapy resistance observed in AML patients and promoted proliferation in a phosphatase-dependent, and Akt-independent manner. These findings reveal that INPP4B(high) has an unexpected role consistent with oncogenesis in AML, in contrast to its previously reported tumor-suppressive role in epithelial cancers. Overall, we propose that INPP4B is a novel prognostic biomarker in AML that has potential to be translated into clinical practice both as a disease marker and therapeutic target.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Drug Resistance, Neoplasm , Leukemia, Myeloid, Acute/metabolism , Leukemia, Myeloid, Acute/therapy , Phosphoric Monoester Hydrolases/metabolism , fms-Like Tyrosine Kinase 3/metabolism , Adolescent , Adult , Aged , Aged, 80 and over , Apoptosis/drug effects , Apoptosis/radiation effects , Blotting, Western , Cell Proliferation/drug effects , Cell Proliferation/radiation effects , Chemoradiotherapy , Cytarabine/administration & dosage , Daunorubicin/administration & dosage , Female , Fluorescent Antibody Technique , Follow-Up Studies , Humans , Immunoenzyme Techniques , Leukemia, Myeloid, Acute/mortality , Leukemia, Myeloid, Acute/pathology , Male , Middle Aged , Mutation/genetics , Neoplasm Staging , Nucleophosmin , Phosphoric Monoester Hydrolases/genetics , Prognosis , RNA, Messenger/genetics , Radiation, Ionizing , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Survival Rate , Tandem Repeat Sequences/genetics , Tumor Cells, Cultured , Young Adult , fms-Like Tyrosine Kinase 3/genetics
2.
Bone Marrow Transplant ; 48(8): 1040-5, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23396407

ABSTRACT

Success of umbilical cord blood transplantation (UCBT) has been limited by a high rate of graft failure and delayed hematological recovery. It has been postulated that MSCs have hematopoiesis-supportive properties. Therefore, to overcome the limitation of UCBT, third-party UCB-derived MSCs were co-transplanted in recipients receiving unrelated UCBT. Seven patients received UCB and third-party UCB-MSCs. Hematopoietic recovery and transplantation outcomes were compared with historic controls. There was no acute toxicity associated with the infusion of MSCs. The median day to neutrophil engraftment was 19 days in patients, as compared with 24 days in controls (P=0.03). The median day of platelet engraftment was 47 days and 57 days in patients and controls, respectively (P=0.26). In addition, there was no engraftment failure in the MSC group. The incidence of acute and chronic GVHD was comparable between the two groups. However, veno-occlusive disease and TRM did not occur in the MSC group. Third-party UCB-MSCs infusion was safe and feasible. MSCs may also enhance the engraftment of UCBT and prevent rejection. In addition, MSCs may have a role in decreasing TRM. Randomized, controlled trials are required to confirm these results and longer follow-up will determine the effects of MSCs on the risk of relapse.


Subject(s)
Cord Blood Stem Cell Transplantation/methods , Mesenchymal Stem Cell Transplantation/methods , Acute Disease , Case-Control Studies , Child , Child, Preschool , Cord Blood Stem Cell Transplantation/adverse effects , Female , Graft Rejection/prevention & control , Graft Survival , Graft vs Host Disease/etiology , Graft vs Host Disease/prevention & control , Humans , Leukemia/surgery , Male , Mesenchymal Stem Cell Transplantation/adverse effects , Treatment Outcome
3.
Bone Marrow Transplant ; 48(1): 68-73, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22635247

ABSTRACT

From January 2004 to December 2008, 50 consecutive patients with high-risk neuroblastoma were assigned to receive tandem HDCT (high-dose chemotherapy)/auto-SCT after nine cycles of induction chemotherapy. CEC (carboplatin + etoposide + cyclophosphamide) regimen and TM (thiotepa + melphalan)-TBI regimen (or TM regimen for stage 3 patients) were the first and second HDCT regimens. Local radiotherapy, differentiation therapy with 13-cis-retinoid acid and immunotherapy with interleukin-2 were given after tandem HDCT/auto-SCT. Of the 50 patients, 49 underwent a first HDCT/auto-SCT and 47 underwent a second HDCT/auto-SCT. The tumor relapsed or progressed in 14 patients, secondary malignancy developed in one patient and one patient died from chronic lung disease. Therefore, 34 patients remained event free with a median follow-up of 54.5 months (range, 14-94 months) from diagnosis. The probabilities of 5-year OS and EFS for all 50 patients were 77.0% (95% confidence interval (CI), 63.7-90.3) and 71.4% (95% CI, 58.7-84.1), respectively. However, all patients who remained event free for >3 years after tandem HDCT/auto-SCT experienced late adverse effects. Chemotherapeutic dose-escalation strategy using tandem HDCT/auto-SCT was very encouraging for survival. However, further studies incorporating newer treatment modalities are needed to reduce late adverse effects without jeopardizing the survival rate.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Induction Chemotherapy , Neuroblastoma/therapy , Radiotherapy/methods , Stem Cell Transplantation , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/adverse effects , Antineoplastic Agents/therapeutic use , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Bone Neoplasms/diagnosis , Bone Neoplasms/pathology , Bone Neoplasms/secondary , Bone Neoplasms/therapy , Child , Child, Preschool , Combined Modality Therapy/adverse effects , DNA Copy Number Variations , Feasibility Studies , Humans , Induction Chemotherapy/adverse effects , Infant , Interleukin-2/administration & dosage , Interleukin-2/adverse effects , Interleukin-2/therapeutic use , Isotretinoin/administration & dosage , Isotretinoin/adverse effects , Isotretinoin/therapeutic use , N-Myc Proto-Oncogene Protein , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Neoplasm Staging , Neuroblastoma/diagnosis , Neuroblastoma/pathology , Neuroblastoma/secondary , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Oncogene Proteins/genetics , Oncogene Proteins/metabolism , Prognosis , Prospective Studies , Radiotherapy/adverse effects , Stem Cell Transplantation/adverse effects , Survival Analysis , Transplantation, Autologous , Whole-Body Irradiation/adverse effects
4.
Int J Obes (Lond) ; 34(3): 547-56, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20029379

ABSTRACT

OBJECTIVE: To investigate whether drugs targeting peripheral cannabinoid-1 (CB1) receptor ameliorate adiposity comparable to central CB1-receptor antagonist or not. MEASUREMENTS: Receptor binding assay and functional assay in vitro. Pharmacokinetic parameters in mice, brain uptake clearance of compounds in rats and antagonism on the CB1-agonist-induced hypothermia in mice. Diet consumption, body weight changes, hepatic gene expression of sterol-regulatory element-binding protein-1 (SREBP-1) and plasma/tissue concentrations of compounds in HF diet-induced obese (HF-DIO) mice after acute and chronic treatment. RESULTS: Compound-1, an SR141716A derivative, is a peripheral CB1-receptor-selective antagonist that is 10 times less potent than SR141716A in in vitro evaluations. Although the plasma concentrations of Compound-1 are five times higher than those of SR141716A, its potency is still 10 times lower than that of SR141716A in reducing the consumption of normal or HF diet by mice. Through evaluations of brain uptake and the effect on CB1-agonist-induced hypothermia, it was verified that the blood-brain barrier (BBB) penetration of Compound-1 is much lower than that of SR141716A. In HF-DIO mice, chronic treatment by Compound-1 showed dose-dependent antiobesity activities, while its brain distribution was very low as compared with that of SR141716A. Compound-1's effective doses for antiobesity activity were just over 30 mg kg(-1). However, Compound-1 completely suppressed the elevated hepatic SREBP-1 expression even at 10 mg kg(-1). CONCLUSION: These results suggest that (1) central CB1 receptors mediate anorectic response of CB1-receptor antagonists and (2) peripheral modulations, including SREBP-1 expression, are not major mechanisms in the antiobesity effects of CB1-receptor antagonists.


Subject(s)
Adiposity/drug effects , Feeding Behavior/drug effects , Obesity/drug therapy , Pyrazoles/pharmacology , Receptor, Cannabinoid, CB1/antagonists & inhibitors , Adiposity/physiology , Animals , Benzoxazines/antagonists & inhibitors , Benzoxazines/pharmacokinetics , Benzoxazines/pharmacology , Brain/metabolism , Cricetinae , Cricetulus , Dose-Response Relationship, Drug , Feeding Behavior/physiology , Hypothermia/chemically induced , Male , Mice , Mice, Inbred C57BL , Morpholines/antagonists & inhibitors , Morpholines/pharmacokinetics , Morpholines/pharmacology , Naphthalenes/antagonists & inhibitors , Naphthalenes/pharmacokinetics , Naphthalenes/pharmacology , Obesity/metabolism , Piperidines/pharmacokinetics , Piperidines/pharmacology , Pyrazoles/blood , Pyrazoles/pharmacokinetics , Rats , Rats, Sprague-Dawley , Receptor, Cannabinoid, CB1/agonists , Rimonabant , Sterol Regulatory Element Binding Protein 1/metabolism , Tissue Distribution
5.
Nanotechnology ; 19(10): 105305, 2008 Mar 12.
Article in English | MEDLINE | ID: mdl-21817698

ABSTRACT

We demonstrate a hybrid process for fabricating one-dimensional wire devices. The process is a combination of an alignment procedure using dielectrophoresis and subsequent contact metal formation utilizing electrochemical deposition with non-toxic organic-based Au electrolytes. Several devices have been successfully made from GaN nanowires or multi-walled carbon nanotubes (MWCNTs) using our hybrid technique. We demonstrate that rapid thermal annealing improves the ohmic characteristics by five orders of magnitude in the case of the GaN devices and ∼300% in the case of the MWCNT devices. One of the reasons for this improvement is enhanced gold wetting due to the reduction of grain size at the annealing temperature.

6.
J Pharmacol Exp Ther ; 318(2): 555-62, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16699068

ABSTRACT

Human cathepsin K, a cysteine proteinase of the papain family, has been recognized as a potential drug target for the treatment of osteoporosis. The predominant expression of cathepsin K in osteoclasts has rendered the enzyme into a major target for the development of novel antiresorptive drugs. Now, we report the pharmacological properties of OST-4077 [furan-2-carboxylic acid (1-{1-[4-fluoro-2-(2-oxo-pyrrolidin-1-yl)-phenyl]-3-oxo-piperidin-4-ylcarbamoyl}-cyclohexyl)-amide] as a novel selective cathepsin K inhibitor. Human and rat cathepsin K were inhibited in vitro by OST-4077 with the IC50 values of 11 and 427 nM, respectively. OST-4077 suppressed bone resorption induced by rabbit osteoclasts (IC50, 37 nM) but did not affect bone mineralization or cellular alkaline phosphatase activity in MC3T3-E1 cells. Parathyroid hormone-induced bone resorption was inhibited in a dose-dependent manner in thyroparathyroidectomized rats gavaged with a single dose of OST-4077 (ED50, 69 mg/kg). When given orally twice daily for 4 weeks to 3-month-old ovariectomized (OVX) rats, OST-4077 dose-dependently prevented bone loss, as monitored by bone densitometry, ash content, and urinary excretion of deoxypyridinoline. No change in serum osteocalcin in the OVX rats by OST-4077 suggested that bone formation might not be affected by the agent. In summary, OST-4077 selectively inhibited bone resorbing activities of osteoclasts and prevented bone loss induced by estrogen deficiency but did not affect bone formation. OST-4077, an orally active selective human cathepsin K inhibitor, may have the therapeutic potential for the treatment of diseases characterized by excessive bone loss including osteoporosis.


Subject(s)
Amides/pharmacology , Amides/therapeutic use , Bone Density Conservation Agents/pharmacology , Bone Density Conservation Agents/therapeutic use , Bone Resorption/drug therapy , Cathepsins/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Furans/pharmacology , Furans/therapeutic use , Osteoclasts/drug effects , Alkaline Phosphatase/metabolism , Animals , Biomarkers , Bone Density/drug effects , Bone Resorption/metabolism , Cathepsin K , Cathepsins/genetics , Cloning, Molecular , Estrogens/deficiency , Female , Humans , Ovariectomy , Parathyroid Hormone/pharmacology , Rabbits , Rats , Rats, Sprague-Dawley
7.
Allergy ; 58(7): 585-8, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12823115

ABSTRACT

BACKGROUND: There has been an increase in allergic diseases as a result of increased air pollution emanating from traffic and various industries. OBJECTIVE: This study evaluated the association between air pollution and airway hyperresponsiveness in a cross-sectional study of a cohort of 670 children, aged 10-13 years. METHODS: We measured spirometry and conducted allergic skin tests and methacholine challenge tests in 670 schoolchildren. The methacholine concentration causing a 20% fall in FEV1 (PC20) was used as the threshold of airway hyperresponsiveness (AHR). Thresholds of 16 mg/dl or less were assumed to indicate AHR. RESULTS: All of the schoolchildren had normal pulmonary function. Of the children, 257 (38.3%) had AHR. There was a significant increase in AHR in schoolchildren living near a chemical factory [45.0% (138/306), 6.50 +/- 0.48] compared to those in rural [31.9% (52/163), 9.84 +/- 0.83] and coastal [33.3% (67/201), 7.17 +/- 0.68] areas. Atopy was significantly more prevalent near the chemical factory vs the coastal and rural areas [35.6% (109/306) vs 27.3% (55/201) and 23.3% (38/163), respectively, P < 0.007]. Schoolchildren with atopy had lower PC20 than those without atopy (5.98 +/- 0.60 vs 8.15 +/- 0.45, P < 0.001). Positive allergy skin tests and living in a polluted area were risk factors in multivariate analyses adjusted for sex, parents' smoking habits, age, body mass index, nose symptoms and lung symptoms (odds ratio for location = 2.4875, confidence interval 1.6542-3.7406, P < 0.000; odds ratio for allergy skin test = 1.5782, confidence interval 1.1130-2.2379, P < 0.0104). CONCLUSION: Our findings demonstrate that more children living in polluted areas have airway hyperresponsiveness than do those living in less polluted areas.


Subject(s)
Air Pollutants/adverse effects , Environmental Exposure/adverse effects , Inhalation Exposure/adverse effects , Respiratory Hypersensitivity/epidemiology , Respiratory Hypersensitivity/etiology , Adolescent , Allergens/adverse effects , Child , Child Welfare , Cohort Studies , Cross-Sectional Studies , Female , Humans , Korea/epidemiology , Lung/drug effects , Lung/physiology , Male , Nitrogen Dioxide/adverse effects , Prevalence , Respiratory Hypersensitivity/diagnosis , Skin Tests , Statistics as Topic , Sulfur Dioxide/adverse effects
8.
Allergy ; 57(4): 341-5, 2002 Apr.
Article in English | MEDLINE | ID: mdl-11906366

ABSTRACT

BACKGROUND: The balance between the two subsets of T cell is pivotal for allergic sensitization. OBJECTIVE: We conducted a cross-sectional study of 486 children vaccinated with bacillus Calmette-Guérin (BCG), aged 10-13 years, to evaluate whether tuberculin responses may contribute to airway hyperresponsiveness (AHR). METHODS: Tuberculin skin test, allergic skin test, and methacholine challenge test were done. The methacholine concentration causing a 20% fall (PC20) in forced expiratory volume in 1 second (FEV1) was used as a threshold of AHR. Atopy was defined as a reaction showing a mean wheal size of > or = 3 mm to one or more allergens on skin prick test (SPT). Two tuberculin units of polysorbate-stabilized purified protein derivatives (PPD) were injected intradermally into the volar surface of the forearm. Reactions were read at 48-72 h as the transverse diameter in millimeters of induration. RESULTS: Of the children in the study, 12.3% (60/486) had PPD induration; 7.8% (38/486) of children had PPD induration of greater than 10 mm. The PPD induration size was 10.5 +/- 1.03 mm (confidence interval (CI) 7.19-12.33) in atopic children and 11.2 +/- 0.76 mm (CI 7.89-13.1) in nonatopic children. The differences of PPD induration diameter between the two groups were not significant. There was no difference of log PC20 between PPD induration > or = 10 mm and < 10 mm (0.13 +/- 0.18 vs. 0.42 +/- 0.05). The difference of log PC20 between positive and negative tuberculin response was not significant. Children with atopy had lower log PC20 than those without atopy (0.16 +/- 0.07 vs. 0.51 +/- 0.05, P = 0.001). After adjusting for sex, age, height, weight, tuberculin response, atopy was associated with AHR in multivariate analyses (odds ratio = 1.895, CI 1.285-2.505, P = 0.002). CONCLUSION: These data suggested that a tuberculin response due to mycobacterial infection status have no effect on AHR in schoolchildren.


Subject(s)
Bronchial Hyperreactivity/physiopathology , Tuberculin/immunology , Adolescent , BCG Vaccine/therapeutic use , Bronchial Hyperreactivity/drug therapy , Child , Child Welfare , Cross-Sectional Studies , Dose-Response Relationship, Immunologic , Female , Humans , Korea/epidemiology , Male , Multivariate Analysis , Skin Tests , Tuberculin/drug effects
9.
Biochem Pharmacol ; 62(10): 1379-90, 2001 Nov 15.
Article in English | MEDLINE | ID: mdl-11709198

ABSTRACT

The mechanisms of cadmium-induced toxicity may include oxidative stress, altered redox homeostasis, and injuries to organelles. The current study was designed to study the effect of decreased cellular glutathione (GSH) content by sulfur amino acid deprivation on cadmium toxicity and to identify the signaling pathways responsible for the cytotoxicity. GSH content was increased by cadmium in H4IIE cells prior to cell death, which was prevented by excess GSH or cysteine. Cell viability, however, was not improved by GSH or cysteine complexation of cadmium. Cadmium-induced cytotoxicity was 40-fold potentiated in cells with decreased GSH by sulfur amino acid deprivation. Cadmium in combination with decreased GSH markedly increased apoptotic cell death. Mitogen-activated protein kinases including extracellular signal-regulated kinase 1/2, p38 kinase and c-Jun N-terminal kinase (JNK) were all activated 1-12 hr after sulfur amino acid deprivation. U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene), which inhibited activation of extracellular signal-regulated kinase1/2 and p38 kinase in cells under sulfur amino acid deprivation, completely prevented potentiation in Cd-induced cytotoxicity and apoptosis. Potentiation of cadmium toxicity by sulfur amino acid deprivation was prevented in part by either PD98059 or SB203580, or in cells stably expressing dominant negative mutant of JNK1, and to greater extents by PD98059 in combination with either SB203580 or JNK1(-) transfection. These results demonstrated that decreased cellular GSH content potentiated cytotoxicity induced by cadmium at the level of human exposure, and that the potentiation of cytotoxicity resulted from activation of extracellular signal-regulated kinase1/2 in conjunction with p38 kinase or JNK.


Subject(s)
Amino Acids, Sulfur/metabolism , Butadienes/pharmacology , Cadmium/pharmacology , Enzyme Inhibitors/pharmacology , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Mitogen-Activated Protein Kinases/metabolism , Nitriles/pharmacology , Amino Acids/metabolism , Animals , Cysteine/metabolism , Drug Synergism , Enzyme Activation/drug effects , Flavonoids/pharmacology , Glutathione/metabolism , JNK Mitogen-Activated Protein Kinases , Rats , Tumor Cells, Cultured , p38 Mitogen-Activated Protein Kinases
10.
Cancer Chemother Pharmacol ; 47(6): 511-8, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11459204

ABSTRACT

PURPOSE: DA-125 [(8S,10S)-8-(3-Aminopropanoyloxyacetyl)-10-[(2,6-dideoxy-2-fluoro-alpha-L-talopyranosyl) oxy]-7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-methoxy-5,12-naphthacene-dione hydrochloride] is a novel anthracycline derivative with anticancer activity. In the present study, we compared the cytotoxicity of DA-125 with that of doxorubicin in H4IIE rat hepatoma cells and investigated the mechanistic basis. Because activation of MAP kinases, in particular c-Jun N-terminal kinase (JNK), is implicated in apoptotic cell death, the signaling pathways responsible for DA-125-induced apoptosis were studied. METHODS: Cytotoxicity and apoptosis were measured in H4IIE cells and cells were stably transfected with a dominant-negative mutant of JNK1 (JNK1-) by MTT and TUNEL assays. Inhibition of topoisomerase II activity was determined in vitro. Drug accumulation and DNA binding affinity were determined by fluorescence spectroscopy. RESULTS: The cytotoxicity of DA-125 was greater than that of doxorubicin (IC50 11.5 vs 70 microM). DA-125 induced apoptosis with 30-fold greater potency than doxorubicin. Inhibition of topoisomerase II by DA-125 was fourfold greater. The presence of excess beta-alanine, a DA-125 moiety, failed to alter cytotoxicity and accumulation of DA-125, indicating that the improved cytotoxicity of DA-125 did not result from the beta-alanine moiety. Greater cellular accumulation of DA-125 correlated with its high-affinity DNA binding. Although neither PD98059 nor SB203580 altered the degree of cytotoxicity induced by DA-125, JNK1 cells exhibited about a twofold greater viability than control cells. DA-125-induced apoptosis was also decreased in JNK1- -transfected cells. CONCLUSIONS: DA-125 potently inhibited topoisomerase II activity and induced apoptosis by a high rate of prooxidant production. DA-125 exhibited high-affinity DNA binding with improved cellular drug accumulation. Apoptosis induced by DA-125 involved the pathway of JNK1, but not ERK1/2 or p38 kinase.


Subject(s)
Antineoplastic Agents/pharmacology , DNA, Neoplasm/metabolism , Doxorubicin/pharmacology , Enzyme Inhibitors/pharmacology , Mitogen-Activated Protein Kinases/metabolism , Topoisomerase II Inhibitors , Animals , Antineoplastic Agents/metabolism , Carcinoma, Hepatocellular/drug therapy , Carcinoma, Hepatocellular/metabolism , Doxorubicin/analogs & derivatives , Doxorubicin/metabolism , JNK Mitogen-Activated Protein Kinases , Liver Neoplasms/drug therapy , Liver Neoplasms/metabolism , Peroxidase/metabolism , Rats , Tumor Cells, Cultured , beta-Alanine/metabolism
11.
Toxicol Lett ; 121(1): 45-55, 2001 Apr 08.
Article in English | MEDLINE | ID: mdl-11312036

ABSTRACT

Sulfur amino acid deficiency occurs in certain pathophysiological situations (e.g. protein-calorie malnutrition). Previous studies revealed that sulfur amino acid deprivation (SAAD) activated MAP kinases and potentiated cadmium-induced cytotoxicity by activation of ERK1/2 in conjunction with p38 kinase or JNK. The present study was designed to determine susceptibility of cells to a variety of heavy metals in combination with SAAD. Viability was assessed in H4IIE cells treated with sodium arsenite, mercuric chloride, sodium selenite, lead acetate, chromium trioxide or manganese chloride. SAAD potentiated the cytotoxicity of H4IIE cells by arsenic or mercury (i.e. EC50, 19 and 5 microM in SAAD vs. 401 and 42 microM in control medium, respectively). TUNEL assays revealed that the potentiated arsenic or mercury toxicity involved apoptotic cell death. Lead or selenite moderately elicited cell death, which was not enhanced by SAAD. Chromium or manganese caused no significant cytotoxicity. Treatment of cells with U0126 [1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene] an ERK1/2 inhibitor or SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole] a p38 kinase inhibitor effectively prevented SAAD-potentiated arsenic toxicity. The potentiated arsenic toxicity was also inhibited in cells stably expressing a dominant negative mutant of c-Jun N-terminal kinase 1 [JNK1(-)]. The inhibitors of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 kinase failed to prevent mercury-induced toxicity enhanced by SAAD. JNK1(-) cells were minimally susceptible to mercury in SAAD medium. These results demonstrated that SAAD potentiated cytotoxicity induced by arsenic or mercury and that activation of ERK1/2, p38 kinase and JNK1 was responsible for the potentiated arsenic toxicity, whereas the mercury toxicity enhanced by SAAD was mediated with the activity of JNK1.


Subject(s)
Amino Acids, Sulfur/deficiency , Arsenic/toxicity , Mercury/toxicity , Mitogen-Activated Protein Kinases/metabolism , Poisons/toxicity , Animals , Cell Survival/drug effects , Enzyme Activation/drug effects , In Situ Nick-End Labeling , Mitogen-Activated Protein Kinase 8 , Rats , Signal Transduction/drug effects , Tetrazolium Salts , Thiazoles , Tumor Cells, Cultured , p38 Mitogen-Activated Protein Kinases
12.
Chem Biol Interact ; 127(1): 13-28, 2000 Jun 15.
Article in English | MEDLINE | ID: mdl-10903416

ABSTRACT

Growth hormone and insulin are the primary determinants for cytochrome P450 2E1 (CYP2E1) expression. The role of glucose on the induction of CYP2E1 by hypophysectomy and on the restorative effect by growth hormone was investigated in the rat liver. Western and Northern blot analyses revealed that hypophysectomy induced CYP2E1 by 5-fold at 1-4 weeks, relative to control, with a concomitant increase in CYP2E1 mRNA. Hypophysectomized rats (HXR) showed a 20% reduction in the plasma glucose level. Hypophysectomy-induced increase in the CYP2E1 mRNA was completely abolished by glucose feeding in drinking water (10%) for 7 days. Treatment of HXR with hGH (2 I.U./kg, twice a day, for 7 days) inhibited the increases in CYP2E1 protein and mRNA levels with restoration of the plasma glucose level. In contrast to the effect of human growth hormone (hGH) on CYP2E1 in HXR with free access to foods, CYP2E1 expression failed to be restored by hGH in starving HXR. However, glucose feeding of starving HXR abolished the induction of CYP2E1. Effects of hypophysectomy and hGH treatment were studied in streptozotocin-induced diabetic rats. Insulin, but not hGH, prevented an increase in CYP2E1 mRNA in diabetic rats. The hepatic CYP2E1 induction in hypophysectomized diabetic rats was inhibited by hGH treatment, indicating that the hGH effect on CYP2E1 expression did not involve insulin production. These results provide evidence that the induction of hepatic CYP2E1 by hypophysectomy may result from reduced glucose utilization, and that the effect of hGH on CYP2E1 expression may be mediated with enhanced glucose utilization, but not with insulin production.


Subject(s)
Cytochrome P-450 CYP2E1/biosynthesis , Glucose/metabolism , Human Growth Hormone/pharmacology , Hypophysectomy , Liver/enzymology , Animals , Blood Glucose/metabolism , Cytochrome P-450 CYP2E1/genetics , Enzyme Induction/drug effects , Gene Expression/drug effects , Glucose/administration & dosage , Humans , Male , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Starvation
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