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

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

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

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

OBJECTIVETo explore the mechanisms involved in Staphylococcus aureus (S. aureus) invading human monocytic U937 cells.

METHODSS. aureus were added to U937 cells at multiplicity of infections (MOI) of 20:1 for 0, 15, 30, 60, and 90 minutes, respectively. Cell apoptosis was analyzed with Hoechst 33258 staining and Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) flow cytometry analysis. Akt and nuclear factor-kappaB (NF-kappaB) activities were detected by Western blotting.

RESULTSInfection of U937 cells with S. aureus induced rapid cell death in a time-dependent manner, and the cells displayed characteristic features of apoptosis. S. aureus-induced apoptosis was associated with a prominent downregulation of activated (phosphorylated) Akt and NF-kappaB. The inhibition of phosphorylated Akt by LY294002 led to the inhibition of NF-kappaB in a dose-dependent manner. Inhibition of Akt with LY294002 caused further increase in apoptosis of U937 cells.

CONCLUSIONSS. aureus can stimulate the apoptosis of U937 cells. S. aureus induces apoptosis of U937 cells by inhibiting Akt-regulated NF-kappaB.

Apoptosis ; Chromones ; pharmacology ; Humans ; Morpholines ; pharmacology ; NF-kappa B ; physiology ; Phosphatidylinositol 3-Kinases ; physiology ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; physiology ; Staphylococcus aureus ; pathogenicity ; U937 Cells

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 study the effects of combinative therapy of tumor necrosis factor related apoptosis-inducing ligand (TRAIL) and PI3-K-Akt inhibitor on the growth and apoptosis of nasopharyngeal carcinoma (NPC) cells and underlying mechanisms.

METHODSWith cell growth assay, flow cytometric analysis and Western blotting, the effects of TRAIL and PI3-K-Akt special inhibitor (LY294002) on cell growth, apoptosis and related proteins expressions in CNE-2 cell lines were studied.

RESULTSWhen concentrate of TRAIL>1 ng/ml, viability rate of cells in combinative treatment group with TRAIL and LY294002 was higher than that in the single treatment group with TRAIL (all P<0.05). When concentrate of TRAIL were 10 ng/ml and 100 ng/ml, the combinative treatment induced CNE-2 apoptosis more obviously than single treatments (t were 7.167 and 7.206, all P<0.05). The combination group showed more cleavage of Caspase-8, Caspase-3, Caspase-9 than single treatment groups.

CONCLUSIONSCombinative application of TRAIL and PI3-K-Akt pathway inhibitor inhibits the growth of CNE-2 and induces apoptosis. The mitochondrial dependent pathway is implicated for the underlying mechanism.

Apoptosis ; Carcinoma ; Caspases ; metabolism ; Cell Line, Tumor ; drug effects ; Chromones ; pharmacology ; Humans ; Morpholines ; pharmacology ; Nasopharyngeal Neoplasms ; pathology ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; TNF-Related Apoptosis-Inducing Ligand ; pharmacology

Axin is a negative regulator of the Wnt/beta-catenin pathway and is involved in the regulation of axis formation and proliferation. Involvement of Axin in the regulation of other signaling pathways is poorly understood. In this study, we investigated the involvement of Akt in growth regulation by Axin in L929 fibroblasts stimulated by EGF. Akt activity was increased by EGF treatment and Ras activation, respectively. Both the EGF- and Ras-induced Akt activations were abolished by Axin induction, as revealed by both Western blot and immunocytochemical analyses. The proliferation and Akt activation induced by EGF were decreased by Axin induction, and the effects of EGF were abolished by treatment of an Akt-specific inhibitor. Therefore, Axin inhibits EGF-induced proliferation of L929 fibroblasts by blocking Akt activation.
Animals ; Cell Line ; Cell Nucleus/metabolism ; Cell Proliferation ; Epidermal Growth Factor/*pharmacology ; Fibroblasts/drug effects/physiology ; Mice ; Proto-Oncogene Proteins c-akt/antagonists & inhibitors/*metabolism ; Repressor Proteins/genetics/*physiology ; Signal Transduction ; ras Proteins/biosynthesis/genetics

OBJECTIVETo explore the signal transduction pathway in the differentiation and apoptosis of leukemia cells induced by heat shock protein 90 (HSP90) inhibitor 17-Allyl amide-17-demethoxygeldanamycin (17AAG).

METHODSKasumi-1 cells were treated with increasing concentrations or exposure time of 17AAG. The total kit protein (CD117), phosphorylated kit protein and its downstream signaling molecules were measured by Western blot analysis. Mutated kit protein from control and 17AAG-treated Kasumi-1 cells was immunoprecipitated and immunoblotted for associated chaperones.

RESULTSTotal kit protein and kit activity were decreased in 17AAG treated cells, but c-kit mRNA level was not. Total AKT protein and phospho-AKT, as well as phospho-STAT3 were rapidly down-regulated in Kasumi-1 cell after treatment with 17AAG. There was no change in total STAT3 protein. Immunoprecipitation showed that 1 microM 17AAG treatment for 1 hour caused kit associated HSP90 decrease and HSP70 increase.

CONCLUSION17AAG-induced apoptosis of Kasumi-1 cells is associated with a decline in Asn822Lys mutated kit protein level and phosphorylated kit, and with a downregulation in its downstream activated signaling molecules involved in proliferation. AKT is a client protein of HSP90. The changes of kit associated HSP90 and HSP70 satisfy the circulation mode of molecular chaperone complex.

Apoptosis ; drug effects ; Benzoquinones ; pharmacology ; Cell Differentiation ; drug effects ; HSP90 Heat-Shock Proteins ; antagonists & inhibitors ; Heat-Shock Proteins ; metabolism ; Humans ; Lactams, Macrocyclic ; pharmacology ; Leukemia ; metabolism ; pathology ; Proto-Oncogene Proteins c-akt ; metabolism ; Proto-Oncogene Proteins c-kit ; metabolism ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; drug effects ; Tumor Cells, Cultured