Epilepsy ; drug therapy ; metabolism ; Humans ; Signal Transduction ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism

OBJECTIVETo study the effects of rapamycin on cell growth and cell cycle in CNE-1 and CNE-2 cells.

METHODSGrowth inhibition effect of rapamycin on CNE-1 and CNE-2 cells were assessed by cell counting kit-8 (CCK-8) assay. Morphological alterations of the cells were observed by microscope. Cell cycle and cell apoptosis were analyzed by FCM. The expression of mammalian target of rapamycin (mTOR) was analyzed by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTSThe growth of CNE-1 and CNE-2 cells was inhibited significantly by rapamycin dose-dependently. FCM showed that CNE-1 and CNE-2 cells at 48 hours after rapamycin (150 nmol/L) treatment were arrested in the G0/G1 phase of cell cycle. However rapamycin treatment did not significantly induce apoptosis of CNE-1 and CNE-2 cells (P > 0.05). RT-PCR showed that rapamycin significantly inhibited mRNA expression of mTOR in CNE-2 cells (t = 10.625, P < 0.01).

CONCLUSIONSRapamycin inhibits the growth of CNE-1 and CNE-2 cells by inhibiting the progression of cell cycle, which could be achieved through decreasing the expression of mTOR.

Cell Cycle ; drug effects ; Cell Line, Tumor ; Humans ; Signal Transduction ; drug effects ; Sirolimus ; pharmacology ; TOR Serine-Threonine Kinases ; antagonists & inhibitors

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

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

BACKGROUNDNeurofibromatosis type 1 (NF1) is the most common genetic syndrome predisposing patients to various tumors due to dysregulation of the Ras signaling pathway. Recent research has shown NF1 patients also suffer a spectrum of bone pathologies. The pathogenesis of NF1 bone diseases is largely unknown. There is no current treatment. By Nf1 heterozygote (Nf1+/-) mice and Nf1 conditional knockout mice, we and other groups demonstrated abnormal osteoblast and osteoclast function due to dysregulation of Ras signaling. However, the specific downstream effector pathways linked to NF1 abnormal osteoblastogenesis and osteoclastogenesis have not been defined. In this study, we investigated the Ras downstream effector related with NF1 bone disease.

METHODSWe used Nf1+/+ and Nf1+/- mice as normal and NF1 models. Bone stromal cells extracted from Nf1+/+ and Nf1+/- mice were induced osteoclasts. The osteoclast cell was stained by tartrate resistant acid phosphatase staining. The osteoclast cell number was counted and the surface area of osteoclast cells was calculated under the microscope. The mRNA of mammalian target of rapamycin (mTOR) was determined by quantitative reverse-transcription-polymerase chain reaction. The presence of ribosomal protein S6 kinase was determined by Western blotting.

RESULTSCompared with Nf1+/+ mice, Nf1+/- mice had about 20% more of osteoclast cells. These osteoclast cells were larger in size with more nuclei. Hyperactive mTOR was detected in Nf1+/- osteoclast cells. Inhibition of mTOR signaling by rapamycin in Nf1+/- osteoclasts abrogated abnormalities in cellular size and number.

CONCLUSIONmTOR pathway inhibition may represent a viable therapy for NF1 bone diseases.

Animals ; Male ; Mice ; Neurofibromatosis 1 ; drug therapy ; Osteoclasts ; drug effects ; physiology ; Osteogenesis ; drug effects ; Sirolimus ; pharmacology ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; physiology

The mammalian target of rapamycin (mTOR), a master regulator of translation initiation, has recently emerged as an attractive therapeutic target for cancer therapy. It has been demonstrated that mTOR inhibitors activate several cell survival pathways including phosphatidyl inositol 3-kinase/serine or threonine-specific protein kinase Akt and mitogen-activated protein kinase or extracellular signal-regulated kinase kinase/extracellular signal-regulated kinase while suppressing mTOR signaling in different types of cancer cell lines and human tumor samples and thus make the cancer cells acquire resistance to the mTOR-targeted therapy. However, these cancer cells may be more dependent on (or addicted to) these survival pathways after receiving the mTOR-targeted therapy. It can be assumed that the combination of mTOR inhibitor and the suppressor of these survival pathways might achieve greater efficacy in inhibiting the growth of cancer cells. In this article we discuss the results of many pre-clinical and clinical studies of mTOR targeted therapy, with an emphasis of its effect against the non-small cell lung cancer.
Carcinoma, Non-Small-Cell Lung ; drug therapy ; metabolism ; Humans ; Lung Neoplasms ; drug therapy ; metabolism ; Sirolimus ; therapeutic use ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism

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

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

Studies of epilepsy have mainly focused on the membrane proteins that control neuronal excitability. Recently, attention has been shifting to intracellular proteins and their interactions, signaling cascades and feedback regulation as they relate to epilepsy. The mTOR (mammalian target of rapamycin) signal transduction pathway, especially, has been suggested to play an important role in this regard. These pathways are involved in major physiological processes as well as in numerous pathological conditions. Here, involvement of the mTOR pathway in epilepsy will be reviewed by presenting; an overview of the pathway, a brief description of key signaling molecules, a summary of independent reports and possible implications of abnormalities of those molecules in epilepsy, a discussion of the lack of experimental data, and questions raised for the understanding its epileptogenic mechanism.
Astrocytes/metabolism ; Cell Death ; Epilepsy/diet therapy/drug therapy/*metabolism/virology ; Humans ; Ketogenic Diet ; Protein Binding/physiology ; Protein Kinase Inhibitors/therapeutic use ; Receptors, Cannabinoid/metabolism ; Signal Transduction/*physiology ; Synapses/metabolism ; TOR Serine-Threonine Kinases/antagonists & inhibitors/*metabolism ; Temporal Lobe/metabolism