Animals ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; metabolism ; Humans ; Intracellular Signaling Peptides and Proteins ; antagonists & inhibitors ; metabolism ; Lung Neoplasms ; drug therapy ; metabolism ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism ; Signal Transduction ; drug effects ; Sirolimus ; therapeutic use ; TOR Serine-Threonine Kinases

p70 ribosomal protein S6 kinase (p70S6K), an important member of AGC family, is a kind of multifunctional Ser/Thr kinases, which plays an important role in mTOR signaling cascade. The p70 ribosomal protein S6 kinase is closely associated with diverse cellular processes such as protein synthesis, mRNA processing, glucose homeostasis, cell growth and apoptosis. Recent studies have highlighted the important role of S6K in cancer, which arose interests of scientific researchers for the design and discovery of anti-cancer agents. Herein, the mechanisms of S6K and available inhibitors are reviewed.
Antineoplastic Agents ; Humans ; Protein Kinase Inhibitors ; chemistry ; Ribosomal Protein S6 Kinases, 70-kDa ; antagonists & inhibitors ; metabolism ; Signal Transduction ; TOR Serine-Threonine Kinases

Recent work indicates that an Aurora kinase inhibitor MK-0457 (VX-680), a small-molecule inhibitor of Aurora kinases A, B, C and BCR-ABL, FLT-3, JAK-2, can block the progression of cell growth cycle, causing apoptosis in a range of human tumors. MK-0457 has the activity against expressions of wild-type and mutated bcr-abl gene, including the T315I mutant, and can inhibit the activity of FLT-3, JAK-2 and their mutated types as well. Clinical applications suggest that the MK-0457 has therapeutic effect on the highly refractory CML and CML with poor prognosis, Ph(+) ALL with T315I mutant, relapse refractory AML and JAK-2 positive myeloproliferative diseases (MPD). The intensive preclinical studies and the on-going phase II clinical trials will open up a new vista of therapy for some hematological malignancies. This review focuses on the pharmacologic action of MK-0457 and its clinical trial as well as combined application.
Aurora Kinases ; Hematologic Neoplasms ; classification ; drug therapy ; Humans ; Piperazines ; therapeutic use ; Protein Kinase Inhibitors ; therapeutic use ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors

AIMTo study the direct effect and kinetics of sodium quercetin-7,4'-disulphate (SQDS) on recombinant human protein kinase CK2 holoenzyme.

METHODSThe recombinant human CK2 holoenzyme activity was assayed by detecting incorporation of 32P of [gamma-32P] ATP into the substrate in various conditions.

RESULTSThe recombinant human CK2 was a second messenger (Ca2+, cAMP and cGMP) independent protein kinase. The characterization and function of the reconstituted holoenzyme were consistent with those of native CK2. SQDS was shown to strongly inhibit the holoenzyme activity of recombinant human protein kinase CK2 with an IC50 of 4.4 mumol.L-1, which was more effective than DRB and A3, known CK2 special inhibitors. Kinetic studies of SQDS on recombinant human CK2 showed: the inhibition was competitive with ATP and noncompetitive with casein.

CONCLUSIONSQDS is a potent inhibitor of protein kinase CK2. This study provide experimental basis for the development of more effective inhibitors of CK2 and for clinical application of SQDS in the future.

Casein Kinase II ; Dichlororibofuranosylbenzimidazole ; pharmacology ; Enzyme Inhibitors ; pharmacology ; Humans ; Kinetics ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism ; Quercetin ; analogs & derivatives ; pharmacology ; Recombinant Proteins ; antagonists & inhibitors ; metabolism

OBJECTIVESTo explore the effects of insulin on the expression and the regulatory pathway of AQP9 in normal human liver cells.

METHODSNormal human liver cells L02 were cultured and treated with PI3K inhibitor LY294002, AKT inhibitor A-443654, MAPK inhibitors SB2030580 and insulin at different concentrations respectively. The AQP9 mRNA and protein expressions were detected with semi-quantitative RT-PCR and Western blot respectively.

RESULTSThe insulin (100 nmol/L approximately 500 nmol/L) treatment decreased the expression of AQP9 in normal human liver cells (P less than 0.05) concentration dependently, and the expression of AQP9 began to reduce from 3 hours of insulin stimulation (P less than 0.05), especially at insulin treatment for 12 hours (P less than 0.05); Incubated with the selective inhibitor of PI3K (LY294002) and AKT (A-443654), the inhibitory effects of insulin on AQP9 expression decreased (P less than 0.05); but it did not change significantly by blocking the MAPK signaling pathway.

CONCLUSIONThe insulin treatment inhibited the expression of AQP9 and the PI3K/akt signal transduction pathway was involved in the mechanism.

Aquaporins ; metabolism ; Cells, Cultured ; Chromones ; pharmacology ; Hepatocytes ; drug effects ; metabolism ; Humans ; Insulin ; pharmacology ; Morpholines ; pharmacology ; Phosphatidylinositol 3-Kinase ; antagonists & inhibitors ; metabolism ; Protein-Serine-Threonine Kinases ; metabolism ; Signal Transduction

Malignant tumor, one of the most refractory diseases, plays a threaten role in human health, the therapy and research on malignant tumor have taken a long way to go. The anti-tumor drugs which are the essential therapy strategies upgrade with the development of new anti-tumor targets and the research on tumor pathogenesis. Aurora kinase and Pin1, the novel anti-tumor targets, maintain the important relationship with tumor. Many new compounds designed on these targets have excellent anti-tumor effects and also enter into phase I or phase II clinical trial.
Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Aurora Kinases ; Humans ; NIMA-Interacting Peptidylprolyl Isomerase ; Naphthoquinones ; pharmacology ; Neoplasms ; metabolism ; pathology ; Peptidylprolyl Isomerase ; antagonists & inhibitors ; metabolism ; Piperazines ; pharmacology ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism

OBJECTIVETo investigate the synergistic effect of rapamycin (RPM) and PD98059 on human colorectal cancer cells and its potential mechanisms.

METHODSThree human colorectal cancer cell lines SW480, HCT116 and HT29 were treated with RPM 10 nmol/L, PD98059 (10 micromol/L, 20 micromol/L, 40 micromol/L, 50 micromol/L), or RPM plus PD98059, respectively, and the sensitivity was analyzed by MTT assay. The cell cycle progression was evaluated by flow cytometry. Western blotting analysis was performed to examine the total and phosphorylated levels of mammalian target of rapamycin (mTOR) and its downstream translational signaling intermediates, 70 kDa ribosomal protein S6 kinase (p70s6k) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1).

RESULTSBoth RPM and PD98059 could inhibit viability of the three cell lines. The anti-proliferative effect of PD98059 exhibited a time/dose dependent manner and was strengthen by RPM. All the treatment with RPM, PD98059, and RPM + PD98059 induced arrest of cell cycle, although the arrest was confined at different cell cycle phases. In addition to their effect on proliferation and cell cycle, both inhibitors also reduced phosphorylation levels of mTOR, p70s6k, and 4E-BP1, as well as total 4E-BP1 levels in SW480 and HCT116 cells. That effect was reinforced when cells were treated with RPM plus PD98059 simultaneously, whereas total protein levels of mTOR and p70s6k remained unchanged.

CONCLUSIONRPM and PD98059 inhibit proliferation of colorectal cancer cells synergistically, and induce cell cycle arrest. The modulation of mammalian target of rapamycin signaling pathway is involved in its potential mechanisms.

Adaptor Proteins, Signal Transducing ; metabolism ; Antibiotics, Antineoplastic ; pharmacology ; Calcium-Calmodulin-Dependent Protein Kinases ; antagonists & inhibitors ; Cell Cycle ; drug effects ; Cell Proliferation ; Colorectal Neoplasms ; metabolism ; pathology ; Drug Synergism ; Flavonoids ; pharmacology ; HCT116 Cells ; HT29 Cells ; Humans ; Intracellular Signaling Peptides and Proteins ; antagonists & inhibitors ; metabolism ; Phosphoproteins ; metabolism ; Phosphorylation ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism ; Ribosomal Protein S6 Kinases, 70-kDa ; metabolism ; Signal Transduction ; Sirolimus ; pharmacology ; TOR Serine-Threonine Kinases

OBJECTIVETribbles, a protein family controlling mitogen-activated protein kinase cascades, might contribute to the remodeling process in dilated cardiomyopathy. We investigated the gene expression of Tribble 3 (TRB(3)), cardiac function and collagen changes in rats with diabetic cardiomyopathy (DCM) and the modulating effects of valsartan on them.

METHODSMale Wistar rats were fed with high cholesterol diet throughout the study period, streptozocin (30 mg/kg, i.p) was given at the 28th day, valsartan (30 mg.kg(-1).d(-1), n = 13) or placebo (n = 11) was administered at the 35th day to rats with fasting blood glucose > or = 11.1 mmol/L per gavage for another 12 weeks. Control rats (n = 8) were fed with regular chow. Fasting blood glucose was monitored throughout the study, left ventricular function was determined by echocardiography, myocardial collagen content quantified after Masson-staining and myocardial mRNA expression of TRB(3) detected by quantification real-time RT-PCR at the end of study.

RESULTSCardiac function was significantly improved (EF: 74% +/- 10% vs. 66% +/- 7%, P < 0.05), myocardial collagen content decreased (13.23 +/- 3.14 vs. 16.92 +/- 3.18, P < 0.05) in rats with DCM treated with valsartan. Moreover, TRB(3) mRNA was significantly increased in rats with DCM compared to control rats (0.0198 +/- 0.0082 vs. 0.1108 +/- 0.0933, P < 0.05) and the increase could be significantly attenuated by valsartan (0.0367 +/- 0.0234, P < 0.05 vs. DCM). A significant positive correlation was observed between myocardial TRB(3) mRNA and myocardial collagen content (r = 0.67, P < 0.05) and between TRB(3) mRNA and fasting blood glucose (r = 0.69, P < 0.05) in rats with DCM.

CONCLUSIONOur results show for the first time that myocardial TRB(3) mRNA is upregulated in rats with DCM and which could be down-regulated by valsartan.

Animals ; Cardiomyopathy, Dilated ; metabolism ; physiopathology ; Diabetes Mellitus, Experimental ; Gene Expression ; Male ; Protein Kinases ; metabolism ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors ; RNA, Messenger ; metabolism ; Rats ; Rats, Wistar ; Tetrazoles ; pharmacology ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

Rapamycin and its derivatives (rapalogs), a group of allosteric inhibitors of mammalian target of rapamycin (mTOR), have been actively tested in a variety of cancer clinical trials, and some have been approved by the Food and Drug Administration for the treatment of certain types of cancers. However, the single agent activity of these compounds in many tumor types remains modest. The mTOR axis is regulated by multiple upstream signaling pathways. Because the genes (e.g., PIK3CA, KRAS, PTEN, and LKB1) that encode key components in these signaling pathways are frequently mutated in human cancers, a subset of cancer types may be addicted to a given mutation, leading to hyperactivation of the mTOR axis. Thus, efforts have been made to demonstrate the potential impact of genetic alterations on rapalog-based or mTOR-targeted cancer therapy. This review will primarily summarize research advances in this direction.
Antibiotics, Antineoplastic ; therapeutic use ; Cell Line, Tumor ; Class I Phosphatidylinositol 3-Kinases ; Humans ; Mutation ; Neoplasms ; drug therapy ; metabolism ; PTEN Phosphohydrolase ; genetics ; metabolism ; Phosphatidylinositol 3-Kinases ; genetics ; metabolism ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Proto-Oncogene Proteins p21(ras) ; Signal Transduction ; Sirolimus ; analogs & derivatives ; therapeutic use ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism ; ras Proteins ; genetics ; metabolism

OBJECTIVETo investigate the effect of aurora kinase inhibitor ENMD-2076 on human acute myelogenous leukemia (AML) cell lines.

METHODSAML THP-1 and Kasumi-1 cells were treated with ENMD-2076 for 24 h and 48 h,respectively. Cell growth was measured by MTT assay. Apoptosis was determined using Hoechst staining apoptosis detection kit. Activation of Caspase pathway and expression of apoptosis regulator proteins were detected by Western blot.

RESULTSENMD-2076 significantly induced growth arrest and apoptosis in THP-1 and Kasumi-1 cells. Enhanced apoptosis was observed in ENMD-2076 group evidenced by strong activation of Caspase-9,Caspase-3 and PARP. Furthermore,the ENMD-2076 treatment resulted in down-regulation of anti-apoptotic protein Mcl-1 expression. Also,up-regulated expression of pro-apoptotic protein Bak,Bad and Bax was detected after ENMD-2076 treatment.

CONCLUSIONENMD-2076 can kill effectively AML cells by inhibiting cell growth and inducing apoptosis,which is associated with activation of Caspase pathway and regulation of pro-apoptotic and anti-apoptotic proteins.

Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; metabolism ; Aurora Kinases ; Caspases ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Humans ; Leukemia, Myeloid, Acute ; metabolism ; pathology ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors ; Pyrazoles ; pharmacology ; Pyrimidines ; pharmacology