Sphingosine kinase 1 (SphK1) plays critical roles in cell biological functions. Here we investigated the effects of SphK1 inhibitor SKI II on hepatoma HepG2 cell cycle progression and invasion. Cell survival was determined by SRB assay, cell cycle progression was assayed by flow cytometry, the ability of cell invasion was measured by Matrigel-Transwell assay and protein expression was detected by Western blotting. The results showed that SKI II markedly inhibited HepG2 cell survival in a dose-dependent manner, induced G1 phase arrest in HepG2 cell and inhibited cell invasion. SKI II markedly decreased the expressions of G1-phase-related proteins CDK2, CDK4 and Cdc2 and the levels of cell invasion-associated proteins MMP2 and MMP9. The results showed that SKI II inhibited cell cycle progression and cell invasion, implying SphK1 as a potential target for hepatoma treatment.
CDC2 Protein Kinase ; Cell Movement ; drug effects ; Cell Survival ; drug effects ; Cyclin-Dependent Kinase 2 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; Cyclin-Dependent Kinases ; metabolism ; G1 Phase ; drug effects ; Hep G2 Cells ; Humans ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Phosphotransferases (Alcohol Group Acceptor) ; antagonists & inhibitors ; Thiazoles ; pharmacology

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

The present study was to investigate the effects of exogenous insulin-like growth factor binding protein 7 (IGFBP7) on the proliferation of human breast cancer cell line MDA-MB-453 and its possible mechanism. By means of MTT method in vitro, the results showed exogenous IGFBP7 inhibited the growth of MDA-MB-453 cells (IC50 of IGFBP7 = 8.49 μg/mL) in time- and concentration-dependent manner. SB203580, p38(MAPK) inhibitor, blocked the anti-proliferative effect of exogenous IGFBP7. The flow cytometry assay showed that exogenous IGFBP7 remarkably induced G0/G1 arrest in MDA-MB-453 cells. The Western blot showed that exogenous IGFBP7 promoted phosphorylation of p38(MAPK), up-regulated expression of p21(CIP1/WAF1), and inhibited phosphorylation of Rb. SB203580 restrained exogenous IGFBP7-induced regulation of p21(CIP1/WAF1) and p-Rb in MDA-MB-453 cells. In conclusion, the present study suggests that exogenous IGFBP7 could activate the p38(MAPK) signaling pathway, upregulate p21(CIP1/WAF1) expression, inhibit phosphorylation of Rb, and finally induce G0/G1 arrest in MDA-MB-453 cells.
Breast Neoplasms ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Female ; Humans ; Imidazoles ; pharmacology ; Insulin-Like Growth Factor Binding Proteins ; pharmacology ; Phosphorylation ; Pyridines ; pharmacology ; Signal Transduction ; Somatomedins ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; metabolism

Pyrimidine derivatives have been the subject of much attention in pesticide and medicine fields owing to their unique biological properties. Particularly, a large number of these compounds have recently been reported to show substantial antitumor activities, and some of them have been investigated in clinical trials. Although these structurally novel compounds have a common chemical moiety of a pyrimidine ring, there are a variety of mechanisms of their antitumor action, such as, inhibition of cyclin-dependent-kinases, inhibition of protein tyrosine kinase, inhibition of carbonic anhydrases, inhibition of dihydrofolate reductase and disruption of microtubule assembly. In this paper, we described the latest advances in the research of such pyrimidine derivatives as antitumor drug according to their action on targets.
Animals ; Antineoplastic Agents ; chemistry ; pharmacology ; therapeutic use ; Carbonic Anhydrase Inhibitors ; pharmacology ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinases ; antagonists & inhibitors ; Folic Acid Antagonists ; pharmacology ; Humans ; Neoplasms ; drug therapy ; pathology ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; Pyrimidines ; chemistry ; pharmacology ; therapeutic use ; Tetrahydrofolate Dehydrogenase ; pharmacology ; Tubulin Modulators ; pharmacology ; therapeutic use

Protein arginine methylation is important for a variety of cellular processes including transcriptional regulation, mRNA splicing, DNA repair, nuclear/cytoplasmic shuttling and various signal transduction pathways. However, the role of arginine methylation in protein biosynthesis and the extracellular signals that control arginine methylation are not fully understood. Basic fibroblast growth factor (bFGF) has been identified as a potent stimulator of myofibroblast dedifferentiation into fibroblasts. We demonstrated that symmetric arginine dimethylation of eukaryotic elongation factor 2 (eEF2) is induced by bFGF without the change in the expression level of eEF2 in mouse embryo fibroblast NIH3T3 cells. The eEF2 methylation is preceded by ras-raf-mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK1/2)-p21(Cip/WAF1) activation, and suppressed by the mitogen-activated protein kinase (MAPK) inhibitor PD98059 and p21(Cip/WAF1) short interfering RNA (siRNA). We determined that protein arginine methyltransferase 7 (PRMT7) is responsible for the methylation, and that PRMT5 acts as a coordinator. Collectively, we demonstrated that eEF2, a key factor involved in protein translational elongation is symmetrically arginine-methylated in a reversible manner, being regulated by bFGF through MAPK signaling pathway.
Animals ; Arginine ; Cell Dedifferentiation ; Cyclin-Dependent Kinase Inhibitor p21/genetics/metabolism ; Elongation Factor 2 Kinase/*metabolism ; Fibroblast Growth Factor 2/*metabolism ; Fibroblasts/*metabolism/pathology ; Flavonoids/pharmacology ; MAP Kinase Signaling System/drug effects/genetics ; Methylation ; Mice ; Mitogen-Activated Protein Kinases/antagonists & inhibitors ; Myofibroblasts/pathology ; NIH 3T3 Cells ; Protein Methyltransferases/*metabolism ; Protein-Arginine N-Methyltransferases/*metabolism ; RNA, Small Interfering/genetics

Protein arginine methylation is important for a variety of cellular processes including transcriptional regulation, mRNA splicing, DNA repair, nuclear/cytoplasmic shuttling and various signal transduction pathways. However, the role of arginine methylation in protein biosynthesis and the extracellular signals that control arginine methylation are not fully understood. Basic fibroblast growth factor (bFGF) has been identified as a potent stimulator of myofibroblast dedifferentiation into fibroblasts. We demonstrated that symmetric arginine dimethylation of eukaryotic elongation factor 2 (eEF2) is induced by bFGF without the change in the expression level of eEF2 in mouse embryo fibroblast NIH3T3 cells. The eEF2 methylation is preceded by ras-raf-mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK1/2)-p21(Cip/WAF1) activation, and suppressed by the mitogen-activated protein kinase (MAPK) inhibitor PD98059 and p21(Cip/WAF1) short interfering RNA (siRNA). We determined that protein arginine methyltransferase 7 (PRMT7) is responsible for the methylation, and that PRMT5 acts as a coordinator. Collectively, we demonstrated that eEF2, a key factor involved in protein translational elongation is symmetrically arginine-methylated in a reversible manner, being regulated by bFGF through MAPK signaling pathway.
Animals ; Arginine ; Cell Dedifferentiation ; Cyclin-Dependent Kinase Inhibitor p21/genetics/metabolism ; Elongation Factor 2 Kinase/*metabolism ; Fibroblast Growth Factor 2/*metabolism ; Fibroblasts/*metabolism/pathology ; Flavonoids/pharmacology ; MAP Kinase Signaling System/drug effects/genetics ; Methylation ; Mice ; Mitogen-Activated Protein Kinases/antagonists & inhibitors ; Myofibroblasts/pathology ; NIH 3T3 Cells ; Protein Methyltransferases/*metabolism ; Protein-Arginine N-Methyltransferases/*metabolism ; RNA, Small Interfering/genetics

The objective of study was to investigate the combined effect of tyrosine-kinase inhibitor (imatinib) and p15 gene on the proliferation, cell cycle and apoptosis of chronic myeloid leukemia cell line K562. p15 gene was amplified from peripheral blood mononuclear cells by RT-PCR, and confirmed by DNA sequencing, then the recombinant p15-pcDNA3.1 vector was constructed and transfected into K562 cell line by Lipofectine. After screening with G418, p15-pcDNA3.1-K562 cell clone stably expressing P15 was isolated. P15 protein was identified by Western blot. The cell survival rate was determined by MTT, cell cycle and apoptosis were detected by flow cytometry. The results showed that partial deletion of p15 gene in K562 cells was verified by DNA sequencing, leading to the function of P15 protein to be lost. The expression of P15 protein can be detected by Western blot in p15-pcDNa3.1-K562 cells. A strong inhibition of cell proliferation was observed in p15-pcDNA3.1-K562 cells as compared with that of the control K562 cell. The cells of G(0)/G(1) phase in p15-pcDNA3.1-K562 cells increased apparently, and S phase cells declined signifcantly. Cell cycle was arrested in G(0)/G(1) phase. The percentage of apoptotic cells greatly increased after transfection with p15-pcDNA3.1-K562 cells combined with imatinib, and cell survival rate notably declined. It is concluded that the imatinib in combination with the expression of p15 gene has a synergistic effect on the inhibition of K562 cell proliferation and promotion of its apoptosis.
Apoptosis ; drug effects ; Base Sequence ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinase Inhibitor p15 ; genetics ; Humans ; K562 Cells ; Molecular Sequence Data ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; Transfection

Animals ; Antineoplastic Agents ; pharmacology ; therapeutic use ; Cell Cycle ; drug effects ; physiology ; Cyclin-Dependent Kinases ; antagonists & inhibitors ; metabolism ; Cyclins ; metabolism ; Flavonoids ; pharmacology ; therapeutic use ; Humans ; Neoplasms ; drug therapy ; metabolism ; pathology ; Piperidines ; pharmacology ; therapeutic use ; Purines ; pharmacology ; therapeutic use ; Staurosporine ; analogs & derivatives ; pharmacology ; therapeutic use

Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Chromones ; pharmacology ; Cyclin-Dependent Kinase Inhibitor p27 ; antagonists & inhibitors ; physiology ; Endometrial Neoplasms ; drug therapy ; pathology ; Estradiol ; pharmacology ; Female ; G1 Phase ; drug effects ; Humans ; Intracellular Signaling Peptides and Proteins ; antagonists & inhibitors ; physiology ; Morpholines ; pharmacology ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; physiology ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; physiology ; Signal Transduction ; drug effects ; physiology

OBJECTIVETo screen and evaluate the active constituents of Chinese medicinal herbs as potent inhibitors of Cdc25 phosphatase.

METHODSThe affinity chromatography purified glutashione-S-transferase/Cdc25A phosphatase fusion protein and Cdc2/cyclin B from the extracts of starfish M phase oocytes are used as the cell cycle-specific targets for screening the antimitotic constituents. We tested 9 extracts isolated from the Chinese medicinal herbs and vegetables including the agents currently used in cancer treatment by measuring the inhibition of Cdc25A phosphatase and Cdc2 kinase activity. The antitumor activity of the extracts was also evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and flow cytometry.

RESULTSCdc25A inhibitory activity and antitumor activity are detected in the extracts isolated from three Chinese medicinal herbs Agrimona pilosa; Herba solani lyrati; Galla chinesis.

CONCLUSIONWe found three extracts isolated from Chinese medicinal herbs have potential inhibitory activity of Cdc25 phosphatase using a highly specific mechanism-based screen assay for antimitotic drug discovery.

Apoptosis ; drug effects ; Cell Cycle Proteins ; antagonists & inhibitors ; metabolism ; Cell Line, Tumor ; Cyclin-Dependent Kinases ; metabolism ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; analysis ; chemistry ; pharmacology ; Humans ; Lethal Dose 50 ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; drug therapy ; enzymology ; pathology ; Medicine, Chinese Traditional ; methods ; Mitosis ; drug effects ; Phytotherapy ; methods ; Plants, Medicinal ; chemistry ; cdc25 Phosphatases ; antagonists & inhibitors ; metabolism