OBJECTIVE: The purpose of this study was to determine whether xenon post-conditioning affects mTOR signaling as well as endoplasmic reticulum stress (ERS)-apoptosis pathway in rats with spinal cord ischemia/reperfusion injury. METHODS: Fifty male rats were randomized equally into sham-operated group (Sham group), I/R model group (I/R group), I/R model+ xenon post-conditioning group (Xe group), I/R model+rapamycin (a mTOR signaling pathway inhibitor) treatment group (I/R+ Rapa group), and I/R model + xenon post- conditioning with rapamycin treatment group (Xe + Rapa group).. In the latter 4 groups, SCIRI was induced by clamping the abdominal aorta for 85 min followed by reperfusion for 4 h. Rapamycin (or vehicle) was administered by daily intraperitoneal injection (4 mg/kg) for 3 days before SCIRI, and xenon post-conditioning by inhalation of 1∶1 mixture of xenon and oxygen for 1 h at 1 h after initiation of reperfusion; the rats without xenon post-conditioning were given inhalation of nitrogen and oxygen (1∶ 1). After the reperfusion, motor function and histopathologic changes in the rats were examined. Western blotting and real-time PCR were used to detect the protein and mRNA expressions of GRP78, ATF6, IRE1α, PERK, mTOR, p-mTOR, Bax, Bcl-2 and caspase-3 in the spinal cord. RESULTS: The rats showed significantly lowered hind limb motor function following SCIRI (P < 0.01) with a decreased count of normal neurons, increased mRNA and protein expressions of GRP78, ATF6, IRE1α, PERK, and caspase-3, and elevated p-mTOR/mTOR ratio and Bax/Bcl-2 ratio (P < 0.01). Xenon post-conditioning significantly decreased the mRNA and protein levels of GRP78, ATF6, IRE1α, PERK and caspase-3 (P < 0.05 or 0.01) and reduced p-mTOR/mTOR and Bax/Bcl-2 ratios (P < 0.01) in rats with SCIRI; the mRNA contents and protein levels of GRP78 and ATF6 were significantly decreased in I/R+Rapa group (P < 0.01). Compared with those in Xe group, the rats in I/R+Rapa group and Xe+Rapa had significantly lowered BBB and Tarlov scores of the hind legs (P < 0.01), and caspase-3 protein level and Bax/Bcl-2 ratio were significantly lowered in Xe+Rapa group (P < 0.05 or 0.01). CONCLUSION By inhibiting ERS and neuronal apoptosis, xenon post- conditioning may have protective effects against SCIRI in rats. The mTOR signaling pathway is partially involved in this process.
Animals ; Apoptosis ; Caspase 3/metabolism* ; Endoplasmic Reticulum Stress ; Endoribonucleases/pharmacology* ; Injections, Intraperitoneal ; Male ; Neurons/pathology* ; Nitrogen/metabolism* ; Oxygen/metabolism* ; Protein Serine-Threonine Kinases ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; RNA, Messenger/metabolism* ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury/metabolism* ; Sirolimus/pharmacology* ; Spinal Cord Ischemia/pathology* ; TOR Serine-Threonine Kinases/metabolism* ; Xenon/therapeutic use* ; bcl-2-Associated X Protein/metabolism*

OBJECTIVE: To investigate the effect of rapamycin on Parkinson's disease (PD) and its underlying mechanism in mice. METHODS: Sixty SPF adult male C57BL/6 mice were randomly divided into control group, model group and treatment group. 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine(MPTP) was used to induce Parkinson's disease in model group and treatment group. All mice were trained to cross the runway and were subjected to computer-assisted CatWalk. The numbers of tyrosine hydroxylase positive (TH) neurons in the substantia nigra (SN) were assessed by unbiased stereology using the optical fractionator method; protein expression was detected by Western blot analysis; and glutathione peroxidase (GSH-Px), malondialdehyde (MDA) and superoxide dismutase (SOD) were detected by spectrophotometry. RESULTS: In the model group, a decrease in stride rate and an increase in variation of stance and swing were noted by CatWalk system (<0.05 or <0.01); the numbers of TH neurons decreased (<0.01); expression of p-Akt, p-S6K, p-S6 and p-ULK increased (all <0.01); LC3-Ⅱ/Ⅰ ratio decreased (<0.01); MDA level was elevated while the levels of SOD and GSH-PX were reduced (all <0.01). Compared with the model group, after treated with rapamycin, the abnormal behavior including the stride length, variation of stance and swing and step patterns induced by MPTP were all improved (<0.05 or <0.01); the numbers of TH neurons increased (<0.05); the expression of p-Akt, p-S6K, p-S6 and p-ULK was suppressed (all <0.01); the LC3-Ⅱ/Ⅰ ratio was upregulated (<0.05); MDA level decreased while the levels of GSH-Px and SOD increased (all <0.01). CONCLUSIONS Rapamycin inhibits the activation of mTOR pathway, which contributes to protect against the loss of dopaminergic neurons and provide behavioral improvements in mice with Parkinson's disease. These results are partially related to the ability of rapamycin in inducing autophagy and reducing oxidative stress.
Animals ; Behavior, Animal ; drug effects ; Disease Models, Animal ; Male ; Mice ; Mice, Inbred C57BL ; Neuroprotective Agents ; pharmacology ; therapeutic use ; Oxidative Stress ; drug effects ; Parkinson Disease ; drug therapy ; Random Allocation ; Sirolimus ; pharmacology ; therapeutic use ; Substantia Nigra ; drug effects

OBJECTIVE: To investigate the efficacy of brain-targeted rapamycin (T-Rap) in treatment of epilepsy in rats. METHODS: Rapamycin nanoparticles targeting brain were prepared. The epilepsy model was induced by injection of pilocarpine in rats. The rats with pilocarpine-induced epilepsy were treated with rapamycin (Rap group) or brain-targeted rapamycin (T-Rap group). Seizure activity was observed by electroencephalography; the effect on mTOR signaling pathway was detected by Western blot; neuronal death and moss fiber sprouting were analyzed by Fluoro-Jade B (FJB) and Timm's staining, respectively. RESULTS: Electroencephalography showed that both preparation of rapamycin significantly reduced the frequency of spontaneous seizures in rats, and the effect of T-Rap was stronger than that of conventional rapamycin (<0.05). Western blot showed that the phosphorylation levels of S6K and S6 in T-Rap group were lower than those in Rap group (all <0.05), indicating that T-Rap had a stronger inhibitory effect on mTOR signaling pathway. FJB staining showed that T-Rap significantly decreased neuronal death, but there was no significant difference as compared with Rap group. Timm's staining showed that both preparations of rapamycin significantly reduced the germination of mossy fibers, while the effect of T-Rap was more pronounced than Rap group (<0.05). The inhibition of body weight gain of T-Rap group was less than that of Rap group (<0.05). CONCLUSIONS T-Rap has a better therapeutic effect on epilepsy than conventional rapamycin with a less adverse effects in rats.
Animals ; Brain ; drug effects ; Disease Models, Animal ; Epilepsy ; chemically induced ; drug therapy ; Neurons ; drug effects ; Pilocarpine ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; drug effects ; Sirolimus ; pharmacology ; therapeutic use ; Treatment Outcome

Cancer stem cells (CSCs) have tumor initiation, self-renewal, metastasis and chemo-resistance properties in various tumors including colorectal cancer. Targeting of CSCs may be essential to prevent relapse of tumors after chemotherapy. Phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR) signals are central regulators of cell growth, proliferation, differentiation, and apoptosis. These pathways are related to colorectal tumorigenesis. This study focused on PI3K and mTOR pathways by inhibition which initiate differentiation of SW620 derived CSCs and investigated its effect on tumor progression. By using rapamycin, LY294002, and NVP-BEZ235, respectively, PI3K and mTOR signals were blocked independently or dually in colorectal CSCs. Colorectal CSCs gained their differentiation property and lost their stemness properties most significantly in dual-blocked CSCs. After treated with anti-cancer drug (paclitaxel) on the differentiated CSCs cell viability, self-renewal ability and differentiation status were analyzed. As a result dual-blocking group has most enhanced sensitivity for anti-cancer drug. Xenograft tumorigenesis assay by using immunodeficiency mice also shows that dual-inhibited group more effectively increased drug sensitivity and suppressed tumor growth compared to single-inhibited groups. Therefore it could have potent anti-cancer effects that dual-blocking of PI3K and mTOR induces differentiation and improves chemotherapeutic effects on SW620 human colorectal CSCs.
AC133 Antigen/genetics/metabolism ; Animals ; Antineoplastic Agents/pharmacology/therapeutic use ; Cell Differentiation/*drug effects ; Cell Line, Tumor ; Cell Survival/drug effects ; Chromones/pharmacology/therapeutic use ; Colorectal Neoplasms/drug therapy/metabolism/pathology ; Humans ; Imidazoles/pharmacology/therapeutic use ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Morpholines/pharmacology/therapeutic use ; Neoplastic Stem Cells/cytology/drug effects/metabolism ; Paclitaxel/pharmacology/therapeutic use ; Phosphatidylinositol 3-Kinases/*antagonists & inhibitors/metabolism ; Quinolines/pharmacology/therapeutic use ; SOXB1 Transcription Factors/genetics/metabolism ; Signal Transduction/*drug effects ; Sirolimus/pharmacology/therapeutic use ; TOR Serine-Threonine Kinases/*antagonists & inhibitors/metabolism ; Xenograft Model Antitumor Assays

OBJECTIVETo observe enhanced effects of polypeptide extract from scorpion venom (PESV) combined Rapamycin on autophagy of H22 hepatoma cells in mice and to explore its possible mechanism.

METHODSThe H22 hepatocarcinoma cell suspension was subcutaneously inoculated into 40 Kunming mice. Then tumor-bearing mice were randomly divided into four groups, i.e., the control group,the high dose PESV group, the low dose PESV group, and the combination group (high dose PESV + Rapamycin), 10 in each group. Mice in high and dose PESV groups were administered with 20 mg/kg and 10 mg/kg PESV respectively by gastrogavage. Mice in the combination group were administered with 2 mg/kg rapamycin and 20 mg/kg PESV by gastrogavage. The intervention lasted for 14 successive days. The tumor volume was measured once every other day, the tumor growth curve was drawn, and then the tumor inhibitory rate calculated. Pathological changes of the tumor tissue were observed by HE staining. Protein expression levels of mammal target of rapamycin (mTOR), UNC-51-like kinase-1 (ULK1), microtubule-associated protein1 light chain3 (MAPILC3A), and Beclin1 were detected by immunohistochemical assay.

RESULTSThe growth of H22 hepatoma transplantation tumor was inhibited in high and low dose PESV groups and the combination group (P < 0.05). And there was statistical difference in tumor weight and tumor volume between the combination group and high and low dose PESV groups (P < 0.05). There was no statistical difference in tumor weight or tumor volume between the high dose PESV group and the low dose PESV group (P > 0.05). lmmunohistochemical assay showed that the protein expression of mTOR was higher, but protein expressions of ULK1, MAP1LC3A, Beclin1 were lower in the control group than in the rest 3 groups (P < 0.05, P < 0.01). Compared with the high dose PESV group, protein expressions of ULK1, MAP1LC3A, and Beclin1 were obviously lower (P < 0.05).

CONCLUSIONPESV combined Rapamycin might inhibit the development of H22 hepatoma transplantation tumor in mice possibly through inhibiting the activity of mTOR, enhancing expressions of ULK1, MAP1LC3A, and Beclin1.

Animals ; Antineoplastic Combined Chemotherapy Protocols ; pharmacology ; therapeutic use ; Autophagy ; drug effects ; Carcinoma, Hepatocellular ; Cell Line, Tumor ; Liver Neoplasms ; Mice ; Neoplasm Transplantation ; Peptides ; Scorpion Venoms ; pharmacology ; therapeutic use ; Sirolimus ; pharmacology ; therapeutic use

BACKGROUNDIdiopathic pulmonary fibrosis (IPF) is the most common and devastating form of interstitial lung disease (ILD) in the clinic. There is no effective therapy except for lung transplantation. Rapamycin is an immunosuppressive drug with potent antifibrotic activity. The purpose of this study was to examine the effects of rapamycin on bleomycin-induced pulmonary fibrosis in rats and the relation to the expression of metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1).

METHODSSprague-Dawley rats were treated with intratracheal injection of 0.3 ml of bleomycin (5 mg/kg) in sterile 0.9% saline to make the pulmonary fibrosis model. Rapamycin was given at a dose of 0.5 mg/kg per gavage, beginning one day before bleomycin instillation and once daily until animal sacrifice. Ten rats in each group were sacrificed at 3, 7, 14, 28 and 56 days after bleomycin administration. Alveolitis and pulmonary fibrosis were semi-quantitatively assessed after HE staining and Masson staining under an Olympus BX40 microscope with an IDA-2000 Image Analysis System. Type I and III collagen fibers were identified by Picro-sirius-polarization. Hydroxyproline content in lung tissue was quantified by a colorimetric-based spectrophotometric assay, MMP-9 and TIMP-1 were detected by immunohistochemistry and by realtime quantitative reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTSBleomycin induced alveolitis and pulmonary fibrosis of rats was inhibited by rapamycin. Significant inhibition of alveolitis and hydroxyproline product were demonstrated when daily administration of rapamycin lasted for at least 14 days. The inhibitory efficacy on pulmonary fibrosis was unremarkable until rapamycin treatment lasted for at least 28 days (P < 0.05). It was also demonstrated that rapamycin treatment reduced the expression of MMP-9 and TIMP-1 in lung tissue that was increased by bleomycin.

CONCLUSIONThese results highlight the significance of rapamycin in alleviating alveolitis and pulmonary fibrosis, which is associated with decreased expression of MMP-9 and TIMP-1.

Animals ; Bleomycin ; pharmacology ; Lung ; drug effects ; metabolism ; Male ; Matrix Metalloproteinase 9 ; metabolism ; Pulmonary Fibrosis ; chemically induced ; drug therapy ; Rats ; Rats, Sprague-Dawley ; Sirolimus ; therapeutic use ; Tissue Inhibitor of Metalloproteinase-1 ; metabolism

Deregulation of the phosphatidylinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) signaling pathway occurs frequently in a wide range of human cancers and is a major driving force in tumorigenesis. Thus, small molecules targeting this pathway are under active development as anticancer therapeutics. Although small-molecule inhibitors of the PI3K-mTOR pathway have shown promising clinical efficacy against human cancers, the emergence of drug resistance may limit their success in the clinic. To date, several resistance mechanisms, including both PI3K-dependent and -independent mechanisms, have been described. Here, we summarize the current understanding of resistance mechanisms to PI3K-mTOR inhibitors and discuss potential strategies for overcoming resistance for potential clinical application.
Antineoplastic Agents ; pharmacology ; therapeutic use ; Drug Resistance, Neoplasm ; Genes, myc ; Humans ; Molecular Targeted Therapy ; methods ; Neoplasms ; drug therapy ; metabolism ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-myc ; metabolism ; Signal Transduction ; Sirolimus ; pharmacology ; therapeutic use ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism

Adult ; Antibiotics, Antineoplastic ; therapeutic use ; Benzamides ; Blast Crisis ; drug therapy ; Drug Resistance, Neoplasm ; Humans ; Imatinib Mesylate ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; drug therapy ; Male ; Piperazines ; pharmacology ; Pyrimidines ; pharmacology ; Sirolimus ; therapeutic use

BACKGROUNDThe mammalian target of rapamycin (mTOR) pathway, a key cellular signaling pathway associated with various cellular functions, has distinct roles in the inflammatory process. In this study, the mTOR inhibitor rapamycin (Rapa) was used to test whether inhibition of mTOR activation attenuates lipopolysaccharide (LPS)-induced acute lung injury (ALI) in a murine model.

METHODSMice pretreated with Rapa or vehicle were given LPS intratracheally. Local cell numbers and inflammatory cytokines present in the bronchoalveolar lavage fluid (BAL), wet-to-dry weight ratio, histopathology of the lungs, and survival were evaluated.

RESULTSThe phosphorylation of S6, a major downstream target of mTOR, had a 3-fold increase in lung tissue after LPS stimulation, but the increase was blocked by Rapa. Rapa reduced the levels of TNF-α (LPS vs. LPS + Rapa, (1672.74 ± 193.73) vs. (539.17 ± 140.48) pg/ml, respectively; P < 0.01) and IL-6 (LPS vs. LPS + Rapa: (7790.88 ± 1170.54) vs. (1968.57 ± 474.62) pg/ml, respectively; P < 0.01) in the BAL fluid. However, Rapa had limited effects on the overall severity of ALI, as determined by the wet-to-dry weight ratio of the lungs, number of neutrophils in the BAL fluid, and changes in histopathology. In addition, Rapa failed to reduce mortality in the LPS-induced ALI model.

CONCLUSIONSWe confirmed that mTOR was activated during LPS-induced ALI and strongly inhibited by Rapa. Although Rapa reduced the levels of the mediators of inflammation, the overall severity and survival of the ALI murine model were unchanged.

Acute Lung Injury ; chemically induced ; drug therapy ; Animals ; Lipopolysaccharides ; Mice ; Mice, Inbred C57BL ; Phosphorylation ; Sirolimus ; pharmacology ; therapeutic use ; TOR Serine-Threonine Kinases ; drug effects

Angioplasty, Balloon, Coronary ; adverse effects ; Aspirin ; pharmacology ; therapeutic use ; Coronary Angiography ; Drug-Eluting Stents ; adverse effects ; Humans ; Male ; Middle Aged ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology ; therapeutic use ; Sirolimus ; pharmacology ; therapeutic use ; Ticlopidine ; analogs & derivatives ; pharmacology ; therapeutic use ; Treatment Outcome ; Tyrosine ; analogs & derivatives ; pharmacology ; therapeutic use