In this study the effects of two unrelated vasodilators, nifedipine and nitroprusside, on the pressor responsiveness to the 1-adrenoceptor full agonist cirazoline and partial agonist Sgd 101/75 in pithed rats were examined. The experiments were performed on the vasoconstriction which was mediated by newly synthetized 1-adrenoceptors after removal of existing 1-adrenoceptors by phenoxybenzamine treatment(5mg/kg, i. p.). The t1/2 for recovery of the maximum response and ED50 of cirazoline were 23.1 +/- 5.5 and 26.9 +/- 7.4 hours, respectively, while that for recovery of the maximum response of Sgd 101/75 was 59.2 +/- 18.9 hours. The relationship between the pressor response and the fractional receptor occupancy for cirazoline showed a rectangular hyperbola. This occupancy-response curve markedly shifted to the right one day after phenoxybenzamine and subsequently returned to the control, indicative of a large receptor reserve. However, for Sgd 101/75 the occupancy-response curve exerted less of a hyperbola and shifited little after phenoxybenzamine. While the maximum response to cirazoline in the control rats was resistant to inhibition by the calcium entry blocker nifedipine, this resistance was significantly reduced one and 3 days after phenoxybenzamine, just as the maximum response to Sgd 101/75 was sensitive to nifedipine in the control rats. Likewise, when nitroprusside was used instead, the results were similar for the cirazoline and Sgd 101/75 effects. In summary, it seems unlikely that the resistance to the calcium entry blocker of the full agonist effect can be wholly ascribed either to the receptor reserves or to the differential calcium utilization itself. Alternatively, it is suggested that the differential resistance to calcium antagonists can result from the magnitude of the variables involved in the activation of 1-adrenoceptor coupling processes depending on the full or partial agonist.
Animal ; Blood Pressure/*drug effects ; Clonidine/*analogs and derivatives/antagonists and inhibitors/pharmacology ; Comparative Study ; Ferricyanides/*pharmacology ; Imidazoles/antagonists and inhibitors/*pharmacology ; Male ; Nifedipine/*pharmacology ; Nitroprusside/*pharmacology ; Rats ; Rats, Inbred Strains ; Vasoconstriction/*drug effects

This study was purposed to explore the changes of possible angiogenetic factors other than VEGF after inhibition of NHE1 and their related mechanisms. The K562 cells were treated by NHE1 specific inhibitor cariporide, the angiogenesis factors after inhibition of NHE1 were screened by using protein chip, the IL-8 expression level after cariporide treatment was detected by real-time quantitative PCR; the K562 cells with stable interference of NHE1 were constructed, the IL-8 expression level after interference of NHE1 was detected by real-time quantitative PCR; the p38 phosphorylation level in K562 cells treated with cariporide was detected by Western blot. After treatment of K562 cells with p38 inhibitor SB203580, the IL-8 expression level was decreased by real-time quantitative PCR. The results of protein chip showed that IL-8 expression decreased after cariporide treatment. Real-time quantitative PCR confirmed this inhibitory effect. The p38 phosphorylation level increased after cariporide treatment. The down-regulation of IL-8 expression induced by cariporide treatment was partially restored after K562 cells were treated with p38 inhibitor SB203580. It is concluded that the inhibition of NHE1 can inhibit IL-8 expression through up-regulation of p38 phosphorylation.
Cation Transport Proteins ; antagonists & inhibitors ; Down-Regulation ; Guanidines ; pharmacology ; Humans ; Imidazoles ; pharmacology ; Interleukin-8 ; metabolism ; K562 Cells ; Phosphorylation ; drug effects ; Pyridines ; pharmacology ; Sodium-Hydrogen Exchanger 1 ; Sodium-Hydrogen Exchangers ; antagonists & inhibitors ; Sulfones ; pharmacology ; p38 Mitogen-Activated Protein Kinases ; metabolism

The mammalian target of rapamycin (mTOR), a serine/threonine protein kinase, acts as a "master switch" for cellular anabolic and catabolic processes, regulating the rate of cell growth and proliferation. Dysregulation of the mTOR signaling pathway occurs frequently in a variety of human tumors, and thus, mTOR has emerged as an important target for the design of anticancer agents. mTOR is found in two distinct multiprotein complexes within cells, mTORC1 and mTORC2. These two complexes consist of unique mTOR-interacting proteins and are regulated by different mechanisms. Enormous advances have been made in the development of drugs known as mTOR inhibitors. Rapamycin, the first defined inhibitor of mTOR, showed effectiveness as an anticancer agent in various preclinical models. Rapamycin analogues (rapalogs) with better pharmacologic properties have been developed. However, the clinical success of rapalogs has been limited to a few types of cancer. The discovery that mTORC2 directly phosphorylates Akt, an important survival kinase, adds new insight into the role of mTORC2 in cancer. This novel finding prompted efforts to develop the second generation of mTOR inhibitors that are able to target both mTORC1 and mTORC2. Here, we review the recent advances in the mTOR field and focus specifically on the current development of the second generation of mTOR inhibitors as anticancer agents.
Antineoplastic Agents ; pharmacology ; Cell Proliferation ; drug effects ; Furans ; pharmacology ; Humans ; Imidazoles ; pharmacology ; Indoles ; pharmacology ; Mechanistic Target of Rapamycin Complex 1 ; Mechanistic Target of Rapamycin Complex 2 ; Morpholines ; pharmacology ; Multiprotein Complexes ; antagonists & inhibitors ; Naphthyridines ; pharmacology ; Neoplasms ; pathology ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Purines ; pharmacology ; Pyridines ; pharmacology ; Pyrimidines ; pharmacology ; Quinolines ; pharmacology ; Signal Transduction ; Sirolimus ; pharmacology ; TOR Serine-Threonine Kinases ; antagonists & inhibitors

This study was aimed to investigate whether the inhibition of NHE1 activity and intracellular acidification can reverse resistance of leukemia cells to the imatinib and to explore downstream signal molecule networks of BCR/ABL in the cells of chronic myelocytic leukemia (CML) patients. The mRNA and protein expression of P-glycoprotein (Pgp) and the drug accumulation were assayed after acidifying the primary leukemia cells of patients or K562/DOX and K562/G01 cells. The effects of intracellular acidification of primary leukemia cells on the phosphorylation level changes of ERK1/2 and p38 MAPK were analyzed by Western blot. The results showed that the intracellular concentration of drugs in the advanced patients increased and the sensitivity of K562/DOX and K562/G01 cells to imatinib was enhanced after intracellular acidification or treatment with NHE1 inhibitor cariporide. With downregulation of intracellular pH, the phosphorylation of p38 MAPK decreased in advanced patients and the phosphorylation of ERK1/2 increased within 3 min and then decreased after 30 min. SB203580, the specific inhibitor of p38 MAPK, displayed a synergistic effect with the inhibitor of NHE1 to downregulate the mRNA and protein expression of Pgp. It is concluded that the inhibiton of NHE1 can significantly decrease the protein expression of Pgp in K562/DOX and K562/G01 cells, increase the accumulation of Rhodamine123 and doxorubicin in the cells of advanced patients and enhance the sensitivity of cells to imatinib in which the p38 MAPK signal transduction pathways involves.
ATP-Binding Cassette, Sub-Family B, Member 1 ; metabolism ; Benzamides ; pharmacology ; Cation Transport Proteins ; antagonists & inhibitors ; metabolism ; Drug Resistance, Neoplasm ; drug effects ; Enzyme Inhibitors ; pharmacology ; Gene Expression Regulation, Leukemic ; Humans ; Imatinib Mesylate ; Imidazoles ; pharmacology ; K562 Cells ; MAP Kinase Signaling System ; Piperazines ; pharmacology ; Pyridines ; pharmacology ; Pyrimidines ; pharmacology ; Sodium-Hydrogen Exchanger 1 ; Sodium-Hydrogen Exchangers ; antagonists & inhibitors ; metabolism ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; metabolism

AIMDesign, synthesis and evaluation of a series of 7-imidazolylalkanamido-1-carboxylalkylbenzodiazepine farnesyltransferase (FTase) inhibitors.

METHODS AND RESULTSCoupling of imidazolylalkylcarboxylic acids and 1-substituted 7-aminobenzodiazepines (5a-5c) yielded 10 new compounds (6-12, 16-18) which were biologically tested against FTase using scintillation proximity assay method.

CONCLUSIONFive target compounds were found to be potential farnesyltransferase inhibitors.

Alkyl and Aryl Transferases ; antagonists & inhibitors ; drug effects ; Benzodiazepines ; chemical synthesis ; chemistry ; pharmacology ; Farnesyltranstransferase ; Imidazoles ; chemical synthesis ; chemistry ; pharmacology ; Inhibitory Concentration 50 ; Molecular Conformation ; Molecular Structure ; Structure-Activity Relationship

We stimulated preadipocyte of mice with calcium acetate, p38 mitogen-activated protein kinase (p38 MAPK) inhibitor SB203580, the paralysors and excitomotors of calcium channel. Then we detected expression level of preadipocyte differentiation's marker genes and calcium signal related acceptor genes by real-time PCR, and determined intracellular free Ca2+ concentration ([Ca2+]i]) with Fura-2/AM, intracellular lipid accumulation by oil red O staining. Our aim was to investigate the potential mechanism between calcium signal and preadipocyte differentiation. The results indicated that the paralysors and excitomotors of calcium channel changed the expression level of lipoprotein lipase (LPL), peroxisome proliferators-activated receptor gamma (PPARgamma), fatty acid synthetase (FAS), and the lipid accumulation, markedly. Compared with exocellular Ca2+'s decrease, inhibited intracellular Ca2+'s liberation can promoted preadipocyte differentiation (P < 0.01), and compared with intracellular Ca2+'s increase, promoted exocellular Ca2+'s ingest inhibited preadipocyte differentiation (P < 0.01). SB203580 degraded [Ca2+]i, promoted differentiation marker genes' expression and lipid accumulation in preadipocyte (P < 0.01). But calcium signal didn't have effects to vitamin D receptor (VDR) and extracellular Ca2+-sensing receptor (CaSR)'s expression. It indicated that calcium signal may effect preadipocyte different and lipid accumulation by p38 MAPK pathway.
Adipocytes ; cytology ; Animals ; Calcium ; metabolism ; Calcium Signaling ; drug effects ; Cell Differentiation ; physiology ; Cells, Cultured ; Imidazoles ; pharmacology ; Lipids ; biosynthesis ; Mice ; Pyridines ; pharmacology ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors

Acyltransferases ; antagonists & inhibitors ; chemistry ; Animals ; Antifungal Agents ; chemical synthesis ; pharmacology ; Benzofurans ; chemical synthesis ; pharmacology ; Benzothiazoles ; chemical synthesis ; pharmacology ; Drug Design ; Enzyme Inhibitors ; chemical synthesis ; pharmacology ; Fungi ; drug effects ; enzymology ; Imidazoles ; chemical synthesis ; pharmacology ; Molecular Structure

OBJECTIVETo explore roles of extracellular signal-regulated kinase (ERK) 1/2, p38 mitogen activated protein kinase (p38 MAPK) and nuclear factor (NF) -KB in expression of inducible nitric oxide synthase (iNOS) in rat alveolar macrophages induced by high mobility group box 1 (HMGB1 ).

METHODSPrimary rat alveolar macrophages (PRAMs) cultured in vitro were incubated with PD98059 ( inhibitor against ERK), SB203580 (inhibitor against p38 MAPK) , PDTC (inhibitor against NF-kappaB), or PD98059 plus SB203580 for 2 hours, respectively. HMGB1 was added into the cultures and incubated with cells for 6 hours. Total RNA of PRAMs was extracted and iNOS mRNA expression was semi-quantified with reverse transcription-polymerase chain reaction ( RT-PCR). Greiss reaction was applied to determine nitrite/nitrate (NO2-/NO3- ) concentration in PRAMs culture supernatants.

RESULTSExpression of iNOS mRNA and NO production in PRAMs culture supernatants were down-regulated by inhibition of ERK or p38 MAPK by PD98059 or SB203580, respectively (P <0. 05). Moreover, inhibition of iNOS expression and NO production was observed after simultaneous pretreatment with PD98059 and SB203580 (P < 0. 05). Expression of iNOS mRNA in PRAMs and NO production in PRAMs culture supernatants were down-regulated by inhibition of NF-kappaB by PDTC (P <0. 05).

CONCLUSIONCellular signal molecules of ERK, p38 MAPK, and NF-kappaB all participate in the expression of iNOS and NO production in PRAMs induced by HMGB1.

Animals ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; physiology ; Flavonoids ; pharmacology ; HMGB1 Protein ; pharmacology ; Imidazoles ; pharmacology ; Macrophages, Alveolar ; metabolism ; Male ; NF-kappa B ; antagonists & inhibitors ; physiology ; Nitric Oxide Synthase Type II ; biosynthesis ; Proline ; analogs & derivatives ; pharmacology ; Pyridines ; pharmacology ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Thiocarbamates ; pharmacology ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; physiology

PURPOSE: Dexmedetomidine, a full agonist of alpha2B-adrenoceptors, is used for analgesia and sedation in the intensive care units. Dexmedetomidine produces an initial transient hypertension due to the activation of post-junctional alpha2B-adrenoceptors on vascular smooth muscle cells (SMCs). The aims of this in vitro study were to identify mitogen-activated protein kinase (MAPK) isoforms that are primarily involved in full, alpha2B-adrenoceptor agonist, dexmedetomidine-induced contraction of isolated rat aortic SMCs. MATERIALS AND METHODS: Rat thoracic aortic rings without endothelium were isolated and suspended for isometric tension recording. Cumulative dexmedetomidine (10(-9) to 10(-6) M) dose-response curves were generated in the presence or absence of extracellular signal-regulated kinase (ERK) inhibitor PD 98059, p38 MAPK inhibitor SB 203580, c-Jun NH2-terminal kinase (JNK) inhibitor SP 600125, L-type calcium channel blocker (verapamil and nifedipine), and alpha2-adrenoceptor inhibitor atipamezole. Dexmedetomidine-induced phosphorylation of ERK, JNK, and p38 MAPK in rat aortic SMCs was detected using Western blotting. RESULTS: SP 600125 (10(-6) to 10(-5) M) attenuated dexmedetomidine-evoked contraction in a concentration-dependent manner, whereas PD 98059 had no effect on dexmedetomidine-induced contraction. SB 203580 (10(-5) M) attenuated dexmedetomidine-induced contraction. Dexmedetomidine-evoked contractions were both abolished by atipamezole and attenuated by verapamil and nifedipine. Dexmedetomidine induced phosphorylation of JNK and p38 MAPK in rat aortic SMCs, but did not induce phosphorylation of ERK. CONCLUSION: Dexmedetomidine-induced contraction involves a JNK- and p38 MAPK-mediated pathway downstream of alpha2-adrenoceptor stimulation in rat aortic SMCs. In addition, dexmedetomidine-induced contractions are primarily dependent on calcium influx via L-type calcium channels.
Adrenergic alpha-2 Receptor Agonists/*pharmacology ; Animals ; Anthracenes/pharmacology ; Aorta/cytology ; Dexmedetomidine/*pharmacology ; Enzyme Inhibitors/pharmacology ; Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors/physiology ; Flavonoids/pharmacology ; Imidazoles/pharmacology ; JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors/*physiology ; Male ; *Muscle Contraction ; Muscle, Smooth, Vascular/drug effects/enzymology/*physiology ; Protein Isoforms/antagonists & inhibitors/physiology ; Pyridines/pharmacology ; Rats ; Rats, Sprague-Dawley ; p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors/physiology

OBJECTIVETo investigate the regulatory effect of erythropoietin-producing hepatocellular receptor (EphA2) on the expression of VEGF protein, a pro-angiogenic factor, via p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway in squamous cell carcinoma of the head and neck(SCCHN) in vitro.

METHODSSCCHN Tu686 cells were transfected with EphA2 overexpression vector pEGFP-N1-EphA2. Western blot was used to detect the expression of p38 MAPK and enzyme-linked immunosorbent assay (ELISA) was applied to assay of VEGF. SB203580 as a inhibitor of p38 MAPK signaling pathway was used.

RESULTSThe expression of VEGF protein was significantly up-regulated in Tu686 cells transfected with EphA2 overexpression vector (535.31 ± 45.71) pg/ml, when compared with Tu686 cells transfected with empty vector (400.99 ± 33.50) pg/ml and Tu686 cells with no transfection (385.30 ± 33.50) pg/ml (F = 17.091, P < 0.01). The expression of phosphorylated p38 MAPK was obviously increased in Tu686 cells with EphA2 overexpression. SB203580 inhibited the expressions of VEGF and phosphorylated p38 MAPK proteins in Tu686 cells with EphA2 overexpression.

CONCLUSIONEphA2 can regulate the expression of VEGF protein and stimulate p38 MAPK signaling pathway.

Carcinoma, Squamous Cell ; metabolism ; Cell Line, Tumor ; Enzyme Inhibitors ; pharmacology ; Head and Neck Neoplasms ; metabolism ; Humans ; Imidazoles ; pharmacology ; MAP Kinase Signaling System ; Pyridines ; pharmacology ; Receptor, EphA2 ; physiology ; Vascular Endothelial Growth Factor A ; metabolism ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; metabolism