Humans ; Leukemia ; drug therapy ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; TOR Serine-Threonine Kinases ; antagonists & inhibitors

BACKGROUNDBmi-1 gene determines the proliferative capacity of normal and leukemia stem cells. Expression of Bmi-1 has been found in all types of myeloid leukemia cells in both humans and mice. This study aimed at assessing the effect of antisense Bmi-1 expression on K562 cells proliferation and p16 protein (p16) expression.

METHODSA transcriptional repressor, Bmi-1 cDNA was cloned by reverse transcriptase polymerase chain reaction (RT-PCR) of its mRNA from K562 cells. A plasmid expressing antisense Bmi-1 mRNA was then constructed by reverse design of PCR primers and cloned to the plasmid pLNCX2; G418 was added to the medium after the plasmid was successfully introduced in K562 cells by lipofectin-mediated DNA transfection. The effects of the antisense expression on the proliferation of K562 cells were analyzed by using microculture tetrazolium and colony forming. Cell cycle was analyzed by using flow cytometry. The p16 expression of K562 cells was observed by immunofluorescence histochemical stain.

RESULTSK562 cells transfected with antisense Bmi-1 plasmid grew significantly slower than that of controls (the parental K562 and cells transfected with empty plasmid). The colony forming ability of antisense Bmi-1 plasmid transfected cells decreased significantly (P < 0.01) compared with controls. The p16 expression of cells transfected with antisense Bmi-1 was upgraded more apparently than that of controls.

CONCLUSIONThe antisense Bmi-1 gene can inhibit the growth of K562 cell and upgrade expression of p16 in K562 cells.

Cell Cycle ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p16 ; analysis ; Humans ; K562 Cells ; Nuclear Proteins ; antagonists & inhibitors ; genetics ; Plasmids ; Polycomb Repressive Complex 1 ; Proto-Oncogene Proteins ; antagonists & inhibitors ; genetics ; RNA, Antisense ; physiology ; Repressor Proteins ; antagonists & inhibitors ; genetics

OBJECTIVETo study the inhibitory effect of Akt inhibitor deguelin on PC-3 human prostate cancer cell lines and its possible mechanism.

METHODSPC-3 human prostate cancer cells were cultured in deguelin at the concentrations of 10, 100, 500 and 1 000 nmol/L for 24, 48 and 72 hours, respectively. Then the inhibitory effect of deguelin on the proliferation of the PC-3 cells was determined by MTT assay and that on the cell cycle was detected by flow cytometry. The expression levels of MDM2 and GSK3beta mRNA were measured by RT-PCR and those of MDM2 and GSK3beta proteins by Western blot.

RESULTSAt 24, 48 and 72 hours, the inhibition rates of deguelin on the proliferation of the PC-3 prostate cancer cells were (91.10 +/- 3.75), (86.39 +/- 1.16) and (79.51 +/- 2.63)% at 10 nmol/L, (82.46 +/- 3.65), (76.84 +/- 0.97) and (69.69 +/- 2.30) % at 100 nmol/L, (81.46 +/- 0.41), (75.56 +/- 1.12) and (54.07 +/- 3.21)% at 500 nmol/L, and (66.77 +/- 2.82), (58.22 +/- 0.35) and (39.34 +/- 2.40)% at 1000 nmol/L, all with statistically significant differences from the control group (P < 0.01). Deguelin at 10, 100, 500 and 1 000 nmol/L increased the cell cycles blocked in the G0/G1 phase ([62.4 +/- 2.2], [63.6 +/- 1.1 ], [65.0 +/- 0.3] and [66.5 +/- 1.9]%, P < 0.01) and reduced the percentage of the S-phase cells ([14.7 +/- 2.4], [11.1 +/- 5.2], [5.8 +/- 1.1] and [7.0 +/- 0.6]%, P < 0.01). RT-PCR and Western blot showed markedly up-regulated expressions of GSK3 P3 a3beta down-regulated expressions of MDM2 mRNA and proteins in the PC-3 cells treated with deguelin.

CONCLUSIONAkt inhibitor deguelin can inhibit the proliferation of PC-3 human prostate cancer cells by affecting the down-stream signal molecules GSK3P3 and betaDM2 in the Akt pathway.

Cell Line, Tumor ; Cell Proliferation ; drug effects ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Humans ; Male ; Prostatic Neoplasms ; metabolism ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Rotenone ; analogs & derivatives ; pharmacology

Mdm2 and Mdm4 are two key negative regulators of the tumor suppressor p53. Deletion of either Mdm2 or Mdm4 induces p53-dependent early embryonic lethality in knockout mouse models. The tissue-specific deletion of Mdm2 induces p53-dependent apoptosis, whereas the deletion of Mdm4 induces both p53-dependent apoptosis and cell cycle arrest. Compared to Mdm4 deletion, Mdm2 deletion causes more severe phenotypic defects. Disrupting the Mdm2 and Mdm4 interaction using knockin mice models causes embryonic lethality that can be completely rescued by the concomitant loss of p53, suggesting that Mdm2 and Mdm4 heterodimerization is critical to inhibit p53 activity during embryogenesis. Overexpression of Mdm2 and Mdm4 in mice induces spontaneous tumorigenesis, which clearly indicates that Mdm2 and Mdm4 are bona fide oncogenes. Studies from these mouse models strongly suggest that blocking Mdm2- and Mdm4-mediated p53 inhibition is an appealing therapeutic strategy for cancer patients with wild-type p53 alleles.
Animals ; Apoptosis ; Cell Cycle Checkpoints ; Mice ; Mice, Knockout ; Models, Animal ; Proto-Oncogene Proteins ; genetics ; metabolism ; Proto-Oncogene Proteins c-mdm2 ; genetics ; metabolism ; Tumor Suppressor Protein p53 ; antagonists & inhibitors ; genetics ; metabolism ; Ubiquitin-Protein Ligases ; genetics ; metabolism

Hepatocellular carcinoma (HCC) is a major global health problem, which has a grave morbidity and mortality. Over the past few decades, no effective systemic therapeutic modalities have been established for patients with the unresectable HCC in advanced stage. Sorafenib is a small molecule that blocks cancer cell proliferation by targeting the intracellular signaling pathway at the level of Raf-1 and B-Raf serine-threonine kinases, and exerts an anti-angiogenic effect by targeting the vascular endothelial growth factor receptor-1, 2 and 3, and platelet-derived growth factor receptor-beta tyrosine kinases. Recently, two clinical successful applications, SHARP and Asia-Pacific trial, of multikinase inhibitor sorafenib represent a significant advance in the treatment of advanced HCC patients without a curative chance. However, because the results of clinical trials show diverse responses in a subset of HCC patients, a molecular classification of HCC through the excavation of specific biomarkers related to its biological behavior is necessary for sorting HCC patients to each group with a biological homogeneity, ultimately leading to the most suitable individualization of molecular targeted therapy in HCC.
Antineoplastic Agents/therapeutic use ; Benzenesulfonates/therapeutic use ; Carcinoma, Hepatocellular/pathology/secondary/*therapy ; Humans ; Liver Neoplasms/blood supply/pathology/*therapy ; Neovascularization, Pathologic ; Proto-Oncogene Proteins B-raf/antagonists & inhibitors/metabolism ; Proto-Oncogene Proteins c-raf/antagonists & inhibitors/metabolism ; Pyridines/therapeutic use ; Receptors, Platelet-Derived Growth Factor/antagonists & inhibitors/metabolism ; Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors/metabolism ; Signal Transduction

AIMTo investigate the inhibitory effects and mechanism of action of isoliensinine (IL) on the proliferation of porcine coronary arterial smooth muscle cells (CASMCs) induced by phenylephrine (Phen) and its mechanisms of action.

METHODSMTT assay, immunohistochemical method and Western blotting were adopted.

RESULTSIL (0.03 - 3 micromol x L(-1)) could inhibit the CASMCs proliferation induced by Phen (0.1 micromol x L(-1)) in a concentration-dependent manner. IL (0.1 micromol x L(-1)) antagonized Phen-induced overexpression of PDGF-beta and bFGF from 0.545 +/- 0.026 and 0.47 +/- 0.03 to 0.458 +/- 0.019 and 0.376 +/- 0.017 (P < 0.01 , P < 0.01). IL (0.1 micromol x L(-1)) also decreased c-fos, c-myc and hsp70 overexpression induced by Phen from 0.57 +/- 0.04, 0.44 +/- 0.04 and (173 +/- 36)% to 0.46 +/- 0.05, 0.372 +/- 0.021 and (115 +/- 35)% respectively (P < 0.01, P < 0.01, P < 0.01).

CONCLUSIONIL exerted antiproliferative effect on CASMCs induced by phenylephrine, and its mechanisms were related to decrease the overexpression of growth factors (PDGF-beta, bFGF), protooncogene (c-fos, c-myc) and hsp70.

Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Coronary Vessels ; cytology ; Dose-Response Relationship, Drug ; Fibroblast Growth Factor 2 ; metabolism ; HSP70 Heat-Shock Proteins ; metabolism ; Isoquinolines ; administration & dosage ; isolation & purification ; pharmacology ; Muscle, Smooth, Vascular ; cytology ; Nelumbo ; chemistry ; Phenylephrine ; antagonists & inhibitors ; Plants, Medicinal ; chemistry ; Proto-Oncogene Proteins c-fos ; metabolism ; Proto-Oncogene Proteins c-myc ; metabolism ; Proto-Oncogene Proteins c-sis ; metabolism ; Swine

The phosphatidylinositol 3 kinase (PI3K) pathway is frequently altered in cancer, including ovarian cancer (OC). Unfortunately, despite a sound biological rationale and encouraging activity in preclinical models, trials of first-generation inhibitors of mammalian target of rapamycin (mTOR) in OC have demonstrated negative results. The lack of patient selection as well as resistance to selective mTOR complex-1 (mTORC1) inhibitors could explain the disappointing results thus far. Nonetheless, a number of novel agents are being investigated, including dual mTORC1/mTORC2, Akt, and PI3K inhibitors. Although it is likely that inhibition of the PI3K/Akt/mTOR pathway may have little effect in unselected OC patients, certain histological types, such as clear cell or endometrioid OC with frequent phosphatidylinositol-4,5-biphosphate 3-kinase, catalytic subunit alpha (PIK3CA) and/or phosphatase and tensin homolog (PTEN) alterations, may be particularly suited to this approach. Given the complexity and redundancy of the PI3K signaling network, PI3K pathway inhibition may be most useful in combination with either chemotherapy or other targeted therapies, such as MEK inhibitors, anti-angiogenic therapy, and hormonal therapy, in appropriately selected OC patients. Here, we discuss the relevance of the PI3K pathway in OC and provide an up-to-date review of clinical trials of novel PI3K inhibitors alone or in combination with cytotoxics and novel therapies in OC. In addition, the challenges of drug resistance and predictive biomarkers are addressed.
Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Drug Resistance, Neoplasm ; Female ; Humans ; Ovarian Neoplasms ; drug therapy ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; physiology ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; physiology ; Signal Transduction ; drug effects ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; physiology

The phosphoinositide 3-kinase-AKT-mammalian target of rapamycin (PI3K-AKT-mTOR) pathway is a frequently hyperactivated pathway in cancer and is important for tumor cell growth and survival. The development of targeted therapies against mTOR, a vital substrate along this pathway, led to the approval of allosteric inhibitors, including everolimus and temsirolimus, for the treatment of breast, renal, and pancreatic cancers. However, the suboptimal duration of response in unselected patients remains an unresolved issue. Numerous novel therapies against critical nodes of this pathway are therefore being actively investigated in the clinic in multiple tumor types. In this review, we focus on the progress of these agents in clinical development along with their biological rationale, the need of predictive biomarkers and various combination strategies, which will be useful in counteracting the mechanisms of resistance to this class of drugs.
Antineoplastic Agents ; therapeutic use ; Drug Resistance, Neoplasm ; Humans ; Molecular Targeted Therapy ; Neoplasms ; drug therapy ; genetics ; metabolism ; PTEN Phosphohydrolase ; genetics ; metabolism ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; metabolism ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; metabolism ; Proto-Oncogene Proteins c-ret ; metabolism ; Sirolimus ; therapeutic use ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism

OBJECTIVETo investigate the effects on chemotherapeutic sensitization of the PI3K inhibitor LY294002 in diffuse large B cell Lymphoma (DLBCL) cell lines ly1, ly8, ly10.

METHODSThe three cell lines were treated with LY294002, or doxorubicin alone or combined or sequentially respectively. Western blotting was used to detect the level of phospho-AKT after the treatment. Flow cytometry combined with annexin V-FITC assay and Brdu incorporation assay were used to analyze the alterations of cell cycle, proliferation, and apoptosis, respectively.

RESULTSLY294002 decreased the level of phospha-AKT efficiently in the three DLBCL cell lines. The ratio of S phase cells was significantly decreased (P < 0.05). Sequential use of LY294002 and doxorubicin increased the ratio of apoptosis and there was significant difference between the sequential group and the other four groups (P < 0.05) at 24, 48, 72(ly1), 48, 72 (ly8) or 24 h (ly10).

CONCLUSIONLY294002 can sensitize doxorubicin-induced apoptosis and may be a potential molecular therapeutic agent targeted at AKT signaling pathway in DLBCL.

Apoptosis ; drug effects ; Cell Line, Tumor ; Humans ; Lymphoma, Large B-Cell, Diffuse ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; Proto-Oncogene Proteins c-akt ; metabolism

Animals ; Apoptosis ; drug effects ; Glutamic Acid ; pharmacology ; Oligonucleotides, Antisense ; pharmacology ; PC12 Cells ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Receptors, Thrombin ; antagonists & inhibitors ; genetics