Objective: A gradient stress model of PC12 cells induced by corticosterone was established to provide a basis for the evaluation and regulation of cell stress. Methods: The effect of corticosterone on cell viability was observed by measuring PC12 cell viability at different concentrations of corticosterone (0~1 000 μmol/L) after different intervention times (8~48 h) to screen the cell models for optimal intervention conditions. Key stress indicators (MDA, SOD, NADH, LDH) were measured spectrophotometrically and microscopically to evaluate the models. Results: When the concentration of corticosterone was below 200 μmol/L and the intervention time was 12 h, the cell viability was below half inactivation rate, which could reduce the confounding factors due to the decrease of cell viability in each group. Compared with the blank control group, corticosterone increased the levels of MDA, NADH and LDH,and decreased the levels of SOD in the model group in a concentration-dependent manner (P＜0.01), which was consistent with the construction of the gradient stress model. Conclusion: A gradient stress injury model of PC12 cells was successfully established, with intervention concentrations of 0 μmol/L, 25 μmol/L, 50 μmol/L, 100 μmol/L, 150 μmol/L and 200 μmol/L corticosterone at an intervention time of 12 h. The degree of stress injury of the cell model was increased gradually, which could be used as a basis and object for conducting cell stress injury assessment and regulation experiments.
Animals ; Cell Survival ; Corticosterone/pharmacology* ; NAD/pharmacology* ; PC12 Cells ; Rats ; Superoxide Dismutase

Bacterial Proteins ; Humans ; Metronidazole/pharmacology* ; Mycobacterium tuberculosis ; NAD ; Nitroreductases ; Tuberculosis, Lymph Node

Inosine 5'-monophosphate dehydrogenase (IMPDH) is a key enzyme of de novo GMP biosynthesis. The expression and activity of IMPDH can be affected by diseases and physiological process. It is the drug target for anticancer, antiviral, antimicrobial and immunosuppressive therapeutics. Not only catalytic action but the other biological functions of IMPDH also play an important role in diseases. The basic functions, mechanism of catalysis, classification of inhibitors, biological functions and the latest advances to IMPDH will be illustrated in this review. It is expected to be helpful to the discovery of new inhibitors and biological functions of IMPDH.
Animals ; Binding Sites ; Catalysis ; Drug Design ; Drug Discovery ; Enzyme Inhibitors ; classification ; pharmacology ; Humans ; IMP Dehydrogenase ; antagonists & inhibitors ; genetics ; metabolism ; Inosine Monophosphate ; metabolism ; Molecular Structure ; NAD ; metabolism ; Polymorphism, Genetic

Nicotinamide phosphoribosyltransferase (NAMPT) catalyzes the first rate-limiting step in converting nicotinamide to NAD(+), essential for a number of enzymes and regulatory proteins involved in a variety of cellular processes, including deacetylation enzyme SIRT1 which modulates several tumor suppressors such as p53 and FOXO. Herein we report that NQO1 substrates Tanshione IIA (TSA) and β-lapachone (β-lap) induced a rapid depletion of NAD(+) pool but adaptively a significant upregulation of NAMPT. NAMPT inhibition by FK866 at a nontoxic dose significantly enhanced NQO1-targeting agent-induced apoptotic cell death. Compared with TSA or β-lap treatment alone, co-treatment with FK866 induced a more dramatic depletion of NAD(+), repression of SIRT1 activity, and thereby the increased accumulation of acetylated FOXO1 and the activation of apoptotic pathway. In conclusion, the results from the present study support that NAMPT inhibition can synergize with NQO1 activation to induce apoptotic cell death, thereby providing a new rationale for the development of combinative therapeutic drugs in combating non-small lung cancer.
Abietanes ; pharmacology ; Apoptosis ; drug effects ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; enzymology ; genetics ; physiopathology ; Cell Line, Tumor ; Cytokines ; antagonists & inhibitors ; genetics ; metabolism ; Enzyme Inhibitors ; pharmacology ; Humans ; NAD ; metabolism ; NAD(P)H Dehydrogenase (Quinone) ; genetics ; metabolism ; Naphthoquinones ; pharmacology ; Nicotinamide Phosphoribosyltransferase ; antagonists & inhibitors ; genetics ; metabolism

Hypoxia, a state of low oxygen, is a common feature of solid tumors and is associated with disease progression as well as resistance to radiotherapy and certain chemotherapeutic drugs. Hypoxic regions in tumors, therefore, represent attractive targets for cancer therapy. To date, five distinct classes of bioreactive prodrugs have been developed to target hypoxic cells in solid tumors. These hypoxia-activated prodrugs, including nitro compounds, N-oxides, quinones, and metal complexes, generally share a common mechanism of activation whereby they are reduced by intracellular oxidoreductases in an oxygen-sensitive manner to form cytotoxins. Several examples including PR-104, TH-302, and EO9 are currently undergoing phase II and phase III clinical evaluation. In this review, we discuss the nature of tumor hypoxia as a therapeutic target, focusing on the development of bioreductive prodrugs. We also describe the current knowledge of how each prodrug class is activated and detail the clinical progress of leading examples.
Anthraquinones ; chemistry ; pharmacology ; Antineoplastic Agents ; chemistry ; pharmacology ; Aziridines ; chemistry ; pharmacology ; Cell Hypoxia ; drug effects ; Humans ; Indolequinones ; chemistry ; pharmacology ; Molecular Structure ; NAD(P)H Dehydrogenase (Quinone) ; chemistry ; pharmacology ; Neoplasms ; drug therapy ; pathology ; Nitrogen Mustard Compounds ; chemistry ; pharmacology ; Nitroimidazoles ; chemistry ; pharmacology ; Phosphoramide Mustards ; chemistry ; pharmacology ; Prodrugs ; chemistry ; pharmacology ; Triazines ; chemistry ; pharmacology

The xylose reductase of Pichia stipitis is one of the most important enzymes. It can be used to build up recombinant Saccharomyces cerevisiae strain for utilizing xylose and producing ethanol. Intercellular redox imbalance caused by NADPH preference over NADH for Pichia stipitis xylose reductase (PsXR) has been considered to be one of the main factors for poor ethanol productivity. Some key amino acids of PsXR, which affect the activity or coenzyme preference, were investigated in our previous study. In this study, Lys21 were rational designed for site-directed mutagenesis to alter coenzyme specificity of PsXR from NADPH and NADH into single NADH. The wild gene and mutagenesis genes were ligated into pET28b, and were transferred into E.coli BL21(DE3). After induced by IPTG, the xylose reductases were purified. Purified mutants K21A (Lys21-->Ala), K21R(Lys21-->Arg) were characterized by steady-state kinetic analysis. The results showed that the coenzyme dependence of K21A was completely reversed to NADH.
Aldehyde Reductase ; metabolism ; Amino Acid Substitution ; genetics ; Coenzymes ; pharmacology ; Escherichia coli ; genetics ; metabolism ; Ethanol ; pharmacology ; Lysine ; genetics ; Mutagenesis, Site-Directed ; NAD ; metabolism ; NADP ; metabolism ; Pichia ; chemistry ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics ; metabolism ; Recombination, Genetic ; Xylose ; pharmacology

AIMTo study the effects of hydroxysafflor yellow A (HSYA) on the mitochondrial function of cortex mitochondrial during cerebral ischemia in rats.

METHODSRat focal cerebral ischemia model in rats was established by ligation of middle cerebral central artery. Cortex mitochondria were isolated and prepared for the measurement of membrane fluidity, swelling, respiratory function, activities of mitochondrial respiratory enzymes and superoxide dismutase (SOD), contents of phospholipid, malondial dehyde (MDA) and Ca2+ to evaluate the function of mitochondria.

RESULTSFocal cerebral ischemia resulted in severe neuronal mitochondrial injuries, which could be alleviated by i.v. HSYA (10, 20 mg x kg(-1)), and nimodipine (Nim, 1.0 mg x kg(-1)). The swelling of mitochondria was ameliorated, the decomposability of membrane phospholipid was decreased, the membrane fluidity of mitochondria was increased, HSYA also significantly inhibited the decrease in the activities of respiratory enzymes and SOD of mitochondria, and the increase in MDA and Ca2+ levels caused by cerebral ischemia in rats.

CONCLUSIONHSYA showed a protective action against the cortex mitochondrial injuries in rats induced by cerebral ischemia. The mechanisms may be derived from reducing lipid peroxides, inhibiting Ca2+ overload, scavenging free radicals and improving the energy metabolism.

Animals ; Brain Ischemia ; metabolism ; pathology ; Calcium ; metabolism ; Chalcone ; analogs & derivatives ; pharmacology ; Male ; Malondialdehyde ; metabolism ; Membrane Fluidity ; drug effects ; Mitochondria ; metabolism ; pathology ; Mitochondrial Swelling ; drug effects ; NAD ; metabolism ; Neuroprotective Agents ; pharmacology ; Quinones ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Superoxide Dismutase ; metabolism

MDM2 is a substrate of caspase-3 in p53-mediated apoptosis. In addition, MDM2 mediates its own ubiquitination in a RING finger-dependent manner. Thus, we investigated whether MDM2 is degraded through a ubiquitin-dependent proteasome pathway in the absence of p53. When HL-60 cells, p53 null, were treated with etoposide, MDM2 was markedly decreased prior to caspase-3-dependent retinoblastoma tumor suppressor protein (pRb) and poly (ADP- ribose) polymerase (PARP) cleavages. Moreover, down-regulation of MDM2 level was not coupled with its mRNA down-regulation. However, the level of MDM2 was partially restored by proteasome inhibitors such as LLnL and lactacystin, even in the presence of etoposide. Our results suggest that, in the p53 null status, MDM2 protein level is decreased by proteasome-mediated proteolysis prior to caspase-3-dependent PARP and pRb cleavages.
Antineoplastic Agents, Phytogenic/pharmacology ; Apoptosis/drug effects/physiology ; Caspases/*metabolism ; Cysteine Endopeptidases/*metabolism ; Down-Regulation (Physiology)/physiology ; Etoposide/pharmacology ; HL-60 Cells ; Human ; Multienzyme Complexes/*metabolism ; NAD+ ADP-Ribosyltransferase/*metabolism ; Proto-Oncogene Proteins/*metabolism ; Retinoblastoma Protein/*metabolism

OBJECTIVETo investigate the protective effect of tert-butylhydroquinone on bone marrow cells in rats from cytotoxicity induced by benzene in vitro.

METHODSThe bone marrow cells in rats were divided into two groups randomizedly. Cells of the control group were stimulated by 0, 5, 10, 15, 20 mmol/L benzene for 2, 4, 6 hours respectively. Cells of the tBHQ-pretreated group were treated by 100 micromol/L tBHQ for 12 hours followed by the same conditions as the control group. The DNA damage was detected by single cell gel electrophoresis assay (SCGE) and cell apoptosis was examined by flow cytometry. The activities of NAD (P) H: quinone oxidoreductase (NQO1) in bone marrow cells of rats were also measured before benzene treatment in two groups.

RESULTSIn control group, the DNA damage and the apoptosis of bone marrow cells was increased with the growing concentration and time of benzene treatment. The DNA migration and the lengths of DNA migration of the bone marrow cells in the rats under 5, 10, 15, 20 mmol/L benzene treatment in the tBHQ-pretreated group were significantly lower than those in control group at the same time point (P < 0.05). The apoptosis of the bone marrow cells in the rats stimulated by 15, 20 mmol/L benzene for 2 hours and 10, 15, 20 mmol/L benzene for 4 hours as well as 5, 10, 15, 20 mmol/L benzene for 6 hours were also significantly lower than those in control group (P < 0.05). The activities of NQO1 in the bone marrow cells in the rats were increased after tBHQ treatment (P < 0.01) (1.62 +/- 0.16 min(-1).mg(-1) vs. the control group: 0.95 +/- 0.08 min(-1).mg(-1)).

CONCLUSIONThe benzene can induce the DNA damage and the apoptosis of bone marrow cells in rats in a time dependent and dose dependent manner to some extent. The tBHQ can protect the bone marrow cells in rats from the cytotoxicity induced by benzene, which can be partly explained by the increase of the NQO1 activity induced by tBHQ.

Animals ; Apoptosis ; drug effects ; Benzene ; toxicity ; Bone Marrow Cells ; cytology ; drug effects ; enzymology ; Cells, Cultured ; DNA Damage ; drug effects ; Dose-Response Relationship, Drug ; Enzyme Inhibitors ; pharmacology ; Hydroquinones ; pharmacology ; Male ; NAD(P)H Dehydrogenase (Quinone) ; metabolism ; Rats ; Rats, Wistar

OBJECTIVETo investigate the protective effect and mechanism of Ecliptae Herba extract on cigarette smoke extract-induced cytotoxicity.

METHODThe effect of Ecliptae Herba extract on CSE-induced NHBE cell proliferation was detected by MTT assay. GSH content was determined by DTNB colorimetry. GST activity was measured by CDNB colorimetric assay. NQO1 activity was detected by NADPH and DCIP. The protein expression was determined by Western blot assay.

RESULTEcliptae Herba extract reduced CSE's inhibitory effect on NHBE cells, recover the decrease in intracellular GSH caused by CSE and reduce the CSE-induced activity of GST and NQO1 and NQO1 protein expression.

CONCLUSIONEcliptae Herba extract can reduce CSE-induced injury on NHBE cells, which may be related to phase II detoxification enzymes.

Cell Line ; Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Eclipta ; chemistry ; Gene Expression ; drug effects ; Humans ; NAD(P)H Dehydrogenase (Quinone) ; genetics ; metabolism ; Protective Agents ; pharmacology ; Smoke ; analysis ; Smoking ; adverse effects ; Tobacco ; chemistry