Drugs are exogenous compounds for human bodies, and will be metabolized by many enzymes after administration. CYP450 enzyme, as a major metabolic enzyme, is an important phase I drug metabolizing enzyme. In human bodies, about 75% of drug metabolism is conducted by CYP450 enzymes, and CYP450 enzymes is the key factor for drug interactions between traditional Chinese medicine( TCM) -TCM, TCM-medicine and other drug combination. In order to make clear the interaction between metabolic enzymes and TCM metabolism, we generally chose the enzymatic activity as an evaluation index. That is to say, the enhancement or reduction of CYP450 enzyme activity was used to infer the inducing or inhibitory effect of active ingredients and extracts of traditional Chinese medicine on enzymes. At present, the common method for measuring metabolic enzyme activity is Cocktail probe drugs, and it is the key to select the suitable probe substrates. This is of great significance for study drug's absorption, distribution, metabolism and excretion (ADME) process in organisms. The study focuses on the interaction between TCMs, active ingredients, herbal extracts, cocktail probe substrates as well as CYP450 enzymes, in order to guide future studies.
Animals ; Cytochrome P-450 Enzyme Inhibitors ; metabolism ; pharmacology ; Cytochrome P-450 Enzyme System ; chemistry ; metabolism ; Drugs, Chinese Herbal ; metabolism ; pharmacology ; Enzyme Activation ; drug effects ; Enzyme Activators ; metabolism ; pharmacology ; Humans

Glucokinase (GK) is a new target for the treatment of type II diabetes mellitus (T2DM). In order to find a structure-simplified small molecule GK activator, 19 salicylic acid derivatives were designed and synthesized based on new lead compound (1). Experimental results showed that the potency of compound 8h is superior to control RO-28-0450 in GK activation.
Drug Design ; Enzyme Activation ; drug effects ; Enzyme Activators ; chemical synthesis ; chemistry ; pharmacology ; Glucokinase ; metabolism ; Hypoglycemic Agents ; chemical synthesis ; chemistry ; pharmacology ; Molecular Structure ; Salicylates ; chemical synthesis ; chemistry ; pharmacology ; Thiazoles ; pharmacology

Animals ; Binding Sites ; Blood Glucose ; metabolism ; Diabetes Mellitus, Type 2 ; blood ; Enzyme Activation ; drug effects ; Enzyme Activators ; chemistry ; pharmacology ; Glucokinase ; chemistry ; metabolism ; Humans ; Hypoglycemic Agents ; chemistry ; pharmacology ; Molecular Conformation ; Phosphorylation ; drug effects ; Sulfones ; pharmacology ; Thiazoles ; pharmacology

BACKGROUNDHepatitis B virus (HBV) X protein (HBx) and p53 could mutually down-regulate at transcriptional level and HBx could bind with p53 protein within its transactivation domain and inhibit the function of p53 protein. In recent years, effects of arsenic trioxide (As2O3) on the expression of p53 protein have been widely studied, while little is known about the activity of p53 protein. This study was undertaken to delineate the effect of HBV X gene and As2O3 on p53 protein expression (level and activity) in HepG2 cells by small hairpin RNA (shRNA)-mediated RNA interference (RNAi) technique.

METHODSCell line HepG2 and cells with stable expression of HBV X gene (HepG2-X) were treated with 2 micromol/L As2O3, with corresponding untreated cells serving as controls. Cell lysates and nuclear extracts were extracted. Total level and the relative activity of p53 protein were detected by modified enzyme-linked immunosorbent assay (ELISA). HBV X gene sequence-specific shRNA expression vector (pXi-1 and pXi-2) and sequence-unrelated control (pXi-3) were transfected into HepG2-X. Single cell clone with stable expression of shRNA was selected and exposed to propagating culture. The effect of As2O3 on p53 protein expression and activity was re-observed.

RESULTSTotal p53 protein level was up-regulated and its relative activity ratio was enhanced by As2O3 in HepG2 and HepG2-X cells. The total p53 protein level induced by As2O3 was up-regulated by HBV X gene expression, while its relative activity was significantly suppressed. The suppression was removed after HBV X gene expression was repressed by shRNA.

CONCLUSIONSAs2O3 up-regulates p53 protein expression and enhance its activity. HBV X up-regulates As2O3 induced-p53 protein expression while suppresses its activity.

Arsenicals ; pharmacology ; Cell Line, Tumor ; Enzyme-Linked Immunosorbent Assay ; Humans ; Oxides ; pharmacology ; RNA Interference ; Trans-Activators ; genetics ; Tumor Suppressor Protein p53 ; analysis

AIMTo determine the involvement of NO signal pathway in the development of hyperalgesia induced by activation of protein kinase C (PKC ), nociceptive responses and nitric oxide synthase(NOS) expression and nitric oxide (NO) content in the spinal cord were observed after administration of Phorbol 12-Myristate-Acetate (PMA), a PKC agonist, in rats.

METHODSNociceptive response was observed by behavioral approach. Pain threshold was assayed using thermal tail-flick test. NADPH-d histochemistry was used to investigate the changes of NOS expression. Nitrate/nitrite (NO3-/NO2-) was assayed to represent NO content of lumbar enlargement of spinal cord.

RESULTSNociceptive response was induced and pain threshold decreased after intrathecal injection of PMA. The number of NADPH-d positive cells increased significantly in the superficial layer of the spinal cord dorsal horn (Laminae I - II ) and the grey matter surrounding the central canal (Laminae X), and the reactive degree of NADPH-d positive soma and processes and NO content of the lumbar enlargement of the spinal cord increased significantly after intrathecal injection of PMA. Pretreatment of PKC inhibitor chelerythrine chloride blocked the changes induced by PMA.

CONCLUSIONThe activation of PKC in the spinal cord neurons might induce spontaneous nociceptive responses and hyperalgesia in rats, as well as promote NOS expression and NO production, suggesting that increase in NO production is one of mechanisms of hyperalgesia induced by activation of PKC.

Animals ; Enzyme Activators ; pharmacology ; Nitric Oxide ; biosynthesis ; Nociception ; drug effects ; Pain Threshold ; drug effects ; Protein Kinase C ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; drug effects ; Spinal Cord ; drug effects ; metabolism ; Tetradecanoylphorbol Acetate ; analogs & derivatives ; pharmacology

In order to investigate the effect of PP2A activator and PP2A inhibitor on proliferation of HL-60 cells and analyze the changes of PP2A activity in patients with acute myeloid leukemia (AML), HL-60 cells were treated with FTY720 alone or in combination with okadaic acid (OA) for 24 hours in culture. Cell proliferation was assayed with CCK8 kit. In addition, 20 AML patients including de novo AML and relapsed AML were enrolled in this study. The activity of PP2A in the peripheral blood mononuclear cells of patients was assayed with a PP2A Immunoprecipitation Phosphatase Assay Kit, the data were analyzed by software SPSS 16.0. The results indicated that as compared with control group, the proliferation of cells in FTY720 group was obviously inhibited (p < 0.05). The proliferation of cells in FTY720 + OA group was slightly inhibited as compared with the control group, there was no statistical difference (p > 0.05), but there was significant difference between the FTY720 + OA and FTY720 groups (p < 0.05). The activity of PP2A in AML patients (453.67 ± 102.52 pmol phosphate) was obviously lower than that in the normal controls (673.29 ± 96.32 pmol phosphate), there was significant difference between them (p < 0.01). It is concluded that the activation or inhibition of PP2A can affect the proliferation of HL-60 cells in vitro. Compared with healthy individuals, the activity of PP2A in AML patients is obviously lower. PP2A protein playing a key role in the occurrence and development of AML may be valuable for the diagnosis and treatment of AML.
Adult ; Aged ; Apoptosis ; Case-Control Studies ; Cell Proliferation ; drug effects ; Enzyme Activators ; pharmacology ; Enzyme Inhibitors ; pharmacology ; Female ; Fingolimod Hydrochloride ; HL-60 Cells ; Humans ; Leukemia, Myeloid, Acute ; metabolism ; Male ; Middle Aged ; Okadaic Acid ; pharmacology ; Propylene Glycols ; pharmacology ; Protein Phosphatase 2 ; antagonists & inhibitors ; metabolism ; Sphingosine ; analogs & derivatives ; pharmacology ; Young Adult

BACKGROUNDHepatitis B virus (HBV) x protein (HBx) in HepG2 cells causes a moderate decrease in proteolysis activity of the proteasome. A highly conserved Kunitz-type serine protease inhibitor domain within 154 amino acid residues of HBx has been identified. In this study, a peptide chain derived from the Kunitz domain (PKD) was used to study its effect on the cell cycle and apoptosis of HepG2 cells, and investigated the function of PKD on the activities of proteasomes and AAA-ATPase p97, which involves in the ubiquitin-proteasome protein degradation pathway.

METHODSThe PKD peptide (Phe-Val-Leu-Gly-Gly-Cys-Arg-His-Lys) was chemically synthesized. MTT assays were used to determine the effects of PKD on HepG2 cell growth. Mouse anti-p97 antibody was developed for Western blotting to detect the expression of p97. ATPase activity of proteasomes was measured using a colorimetric assay. Peptidase activities of proteasomes were analyzed with various peptidase-specific fluorogenic peptide substrates. Flow cytometry was used to determinate cell cycle phase and apoptosis.

RESULTSViability of HepG2 cells decreased in a PKD-dose-dependent manner. Cells exhibited significant cytotoxicity in the presence of 15 mmol/L of PKD. Western blotting analysis showed that expression of p97 was suppressed in HepG2 cells treated with PKD compared to untreated cells. The ATPase activity of proteasomes from immunoprecipitates of HepG2 cells pretreated with PKD was apparently decreased. Chymotryptic activity of proteasomes in HepG2 cells was significantly inhibited by 10 mmol/L PKD; tryptic activity and peptidylglutamyl peptide hydrolase activity of proteasomes were less inhibited by PKD than chymotryptic activity. The cell cycle phase of HepG2 cells treated with PKD for 36 hours was blocked largely at the G(0)-G(1) phase, while untreated control cells were mainly in S phase. PKD also significantly induced apoptosis.

CONCLUSIONSThe peptide derived from Kunitz domain of HBx protein induces HepG2 cell growth arrest and apoptosis, which may result from down-regulation of p97 expression, and decrease of both the ATPase and chymotryptic activities of proteasomes.

Adenosine Triphosphatases ; metabolism ; Animals ; Apoptosis ; drug effects ; Blotting, Western ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Enzyme Activation ; drug effects ; Humans ; Lipopeptides ; chemistry ; pharmacology ; Mice ; Nuclear Proteins ; metabolism ; Trans-Activators ; chemistry ; Viral Regulatory and Accessory Proteins ; chemistry

BACKGROUND/AIMS: 5'-Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a cellular energy sensor that monitors intracellular AMP/adenosine triphosphate (ATP) ratios and is a key regulator of the proliferation and survival of diverse malignant cell types. In the present study, we investigated the effect of activating AMPK by 5-aminoimidazole-4-carboxamide-ribonucleotide (AICAR) in thyroid cancer cells. METHODS: We used FRO thyroid cancer cells harboring the BRAF(V600E) mutation to examine the effect of AICAR on cell proliferation and cell survival. We also evaluated the involvement of mitogen-activated protein kinase (MAPK) pathways in this effect. RESULTS: We found that AICAR treatment promoted AMPK activation and suppressed cell proliferation and survival by inducing p21 accumulation and activating caspase-3. AICAR significantly induced activation of p38 MAPK, and pretreatment with SB203580, a specific inhibitor of the p38 MAPK pathway, partially but significantly rescued cell survival. Furthermore, small interfering RNA targeting AMPK-alpha1 abolished AICAR-induced activation of p38 MAPK, p21 accumulation, and activation of caspase-3. CONCLUSIONS: Our findings demonstrate that AMPK activation using AICAR inhibited cell proliferation and survival by activating p38 MAPK and proapoptotic molecules in FRO thyroid cancer cells. These results suggest that the AMPK and p38 MAPK signaling pathways may be useful therapeutic targets to treat thyroid cancer.
AMP-Activated Protein Kinases/genetics/metabolism ; Aminoimidazole Carboxamide/*analogs & derivatives/pharmacology ; Antineoplastic Agents/*pharmacology ; Caspase 3/metabolism ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Cell Survival/drug effects ; Cyclin-Dependent Kinase Inhibitor p21/metabolism ; Dose-Response Relationship, Drug ; Enzyme Activation ; Enzyme Activators/pharmacology ; Humans ; Mutation ; Protein Kinase Inhibitors/pharmacology ; Proto-Oncogene Proteins B-raf/genetics ; RNA Interference ; Ribonucleotides/*pharmacology ; Signal Transduction/*drug effects ; Thyroid Neoplasms/*enzymology/genetics/pathology ; Time Factors ; Transfection ; p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors/*metabolism

Curcumin, an active ingredient of dietary spice used in curry, has been shown to exhibit anti-oxidant, anti-inflammatory and anti-proliferative properties. Using EB directed differentiation protocol of H-9 human embryonic stem (ES) cells; we evaluated the effect of curcumin (0-20 μmol/L) in enhancing such differentiation. Our results using real time PCR, western blotting and immunostaining demonstrated that curcumin significantly increased the gene expression and protein levels of cardiac specific transcription factor NKx2.5, cardiac troponin I, myosin heavy chain, and endothelial nitric oxide synthase during ES cell differentiation. Furthermore, an NO donor enhanced the curcumin-mediated induction of NKx2.5 and other cardiac specific proteins. Incubation of cells with curcumin led to a dose dependent increase in intracellular nitrite to the same extent as giving an authentic NO donor. Functional assay for second messenger(s) cyclic AMP (cAMP) and cyclic GMP (cGMP) revealed that continuous presence of curcumin in differentiated cells induced a decrease in the baseline levels of cAMP but it significantly elevated baseline contents of cGMP. Curcumin addition to a cell free assay significantly suppressed cAMP and cGMP degradation in the extracts while long term treatment of intact cells with curcumin increased the rates of cAMP and cGMP degradation suggesting that this might be due to direct suppression of some cyclic nucleotide-degrading enzyme (phosphodiesterase) by curcumin. These studies demonstrate that polyphenol curcumin may be involved in differentiation of ES cells partly due to manipulation of nitric oxide signaling.
Animals ; Antioxidants ; pharmacology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Curcumin ; pharmacology ; Cyclic GMP ; metabolism ; Embryoid Bodies ; drug effects ; metabolism ; physiology ; Enzyme Activators ; pharmacology ; Gene Expression ; drug effects ; Guanylate Cyclase ; genetics ; metabolism ; Homeobox Protein Nkx-2.5 ; Homeodomain Proteins ; genetics ; metabolism ; Humans ; Mice ; Myosin Heavy Chains ; genetics ; metabolism ; Nitric Oxide ; metabolism ; Nitric Oxide Donors ; pharmacology ; Nitric Oxide Synthase Type III ; genetics ; metabolism ; Nitroso Compounds ; pharmacology ; Pyrazoles ; pharmacology ; Pyridines ; pharmacology ; Second Messenger Systems ; Transcription Factors ; genetics ; metabolism ; Troponin ; genetics ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

PURPOSE: The ketogenic diet has long been used to treat epilepsy, but its mechanism is not yet clearly understood. To explore the potential mechanism, we analyzed the changes in gene expression induced by the ketogenic diet in the rat kainic acid (KA) epilepsy model. MATERIALS AND METHODS: KA-administered rats were fed the ketogenic diet or a normal diet for 4 weeks, and microarray analysis was performed with their brain tissues. The effects of the ketogenic diet on cathepsin E messenger ribonucleic acid (mRNA) expression were analyzed in KA-administered and normal saline-administered groups with semi-quantitative and real-time reverse transcription polymerase chain reaction (RT-PCR). Brain tissues were dissected into 8 regions to compare differential effects of the ketogenic diet on cathepsin E mRNA expression. Immunohistochemistry with an anti-cathepsin E antibody was performed on slides of hippocampus obtained from whole brain paraffin blocks. RESULTS: The microarray data and subsequent RT-PCR experiments showed that KA increased the mRNA expression of cathepsin E, known to be related to neuronal cell death, in most brain areas except the brain stem, and these increases of cathepsin E mRNA expression were suppressed by the ketogenic diet. The expression of cathepsin E mRNA in the control group, however, was not significantly affected by the ketogenic diet. The change in cathepsin E mRNA expression was greatest in the hippocampus. The protein level of cathepsin E in the hippocampus of KA-administered rat was elevated in immunohistochemistry and the ketogenic diet suppressed this increase. CONCLUSION: Our results showed that KA administration increased cathepsin E expression in the rat brain and its increase was suppressed by the ketogenic diet.
3-Hydroxybutyric Acid/blood ; Animals ; Cathepsin E/genetics/*metabolism ; Enzyme Activators/pharmacology ; *Gene Expression Regulation, Enzymologic/drug effects ; Hippocampus/*drug effects/*metabolism ; Immunohistochemistry ; Kainic Acid/*pharmacology ; *Ketogenic Diet ; Male ; Oligonucleotide Array Sequence Analysis ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction