The purpose of this study was to determine the acute pulmonary toxicity of metallic silver nanoparticles (MSNPs, 20.30 nm in diameter). Acute pulmonary toxicity and body distribution of inhaled MSNPs in mice were evaluated using a nose-only exposure chamber (NOEC) system. Bronchoalveolar lavage (BAL) fluid analysis, Western blotting, histopathological changes, and silver burdens in various organs were determined in mice. Mice were exposed to MSNPs for 6 hrs. The mean concentration, total surface area, volume and mass concentrations in the NOEC were maintained at 1.93 x 10(7) particles/cm3, 1.09 x 10(10) nm2/cm3, 2.72 x 10(11) nm3/cm3, and 2854.62 microg/m3, respectively. Inhalation of MSPNs caused mild pulmonary toxicity with distribution of silver in various organs but the silver burdens decreased rapidly at 24-hrs post-exposure in the lung. Furthermore, inhaled MSNPs induced activation of mitogen-activated protein kinase (MAPK) signaling in the lung. In summary, single inhaled MSNPs caused mild pulmonary toxicity, which was associated with activated MAPK signaling. Taken together, our results suggest that the inhalation toxicity of MSNPs should be carefully considered at the molecular level.
Animals ; Blotting, Western ; Bronchoalveolar Lavage ; Inhalation ; Lung ; Mice ; Nanoparticles ; Protein Kinases ; Silver

Conventional lung cancer therapies are associated with poor survival rates; therefore, new approaches such as gene therapy are required for treating cancer. Gene therapies for treating lung cancer patients can involve several approaches. Among these, aerosol gene delivery is a potentially more effective approach. In this study, Akt1 kinase-deficient (KD) and wild-type (WT) Akt1 were delivered to the lungs of CMV-LucR-cMyc-IRES-LucF dual reporter mice through a nose only inhalation system using glucosylated polyethylenimine and naphthalene was administrated to the mice via intraperitoneal injection. Aerosol delivery of Akt1 WT and naphthalene treatment increased protein levels of downstream substrates of Akt signaling pathway while aerosol delivery of Akt1 KD did not. Our results showed that naphthalene affected extracellular signal-regulated kinase (ERK) protein levels, ERK-related signaling, and induced Clara cell injury. However, Clara cell injury induced by naphthalene was considerably attenuated in mice exposed to Akt1 KD. Furthermore, a dual luciferase activity assay showed that aerosol delivery of Akt1 WT and naphthalene treatment enhanced cap-dependent protein translation, while reduced cap-dependent protein translation was observed after delivering Akt1 KD. These studies demonstrated that our aerosol delivery is compatible for in vivo gene delivery.
Administration, Inhalation ; Aerosols ; Animals ; Gene Expression Regulation ; Gene Knockdown Techniques ; Gene Therapy/*methods ; Gene Transfer Techniques ; Genes, Reporter ; Injections, Intraperitoneal ; Luciferases/genetics/*metabolism ; Lung Diseases/*chemically induced ; Male ; Mice ; Mice, Transgenic ; Naphthalenes/administration & dosage/*toxicity ; Proto-Oncogene Proteins c-akt/*administration & dosage/genetics/*metabolism

Tetrandrine (TET), a bis-benzylisoquinoline alkaloid from the root of Stephania tetrandra, is known to have anti-tumor activity in various malignant neoplasms. However, the precise mechanism by which TET inhibits tumor cell growth remains to be elucidated. The present studies were performed to characterize the potential effects of TET on phosphoinositide 3-kinase/Akt and extracellular signal-regulated kinase (ERK) pathways since these signaling pathways are known to be responsible for cell growth and survival. TET suppressed cell proliferation and induced apoptosis in A549 human lung carcinoma cells. TET treatment resulted in a down-regulation of Akt and ERK phosphorylation in both time-/concentration-dependent manners. The inhibition of ERK using PD98059 synergistically enhanced the TET-induced apoptosis of A549 cells whereas the inhibition of Akt using LY294002 had a less significant effect. Taken together, our results suggest that TET: i) selectively inhibits the proliferation of lung cancer cells by blocking Akt activation and ii) increases apoptosis by inhibiting ERK. The treatment of lung cancers with TET may enhance the efficacy of chemotherapy and radiotherapy and increase the apoptotic potential of lung cancer cells.
Antineoplastic Agents, Phytogenic/*pharmacology ; Apoptosis/drug effects ; Benzylisoquinolines/*pharmacology ; Carcinoma/*drug therapy ; Cell Line, Tumor ; Dose-Response Relationship, Drug ; Extracellular Signal-Regulated MAP Kinases/*antagonists & inhibitors ; Humans ; Lung Neoplasms/*drug therapy

Inorganic phosphate (Pi) plays a critical role in diverse cellular functions, and regulating the Pi balance is accomplished by sodium-dependent Pi co-transporter (NPT). Pulmonary NPT has recently been identified in mammalian lungs. However, to date, many of the studies that have involved Pi have mainly focused on its effect on bone and kidney. Therefore, current study was performed to discover the potential effects of low Pi on the lung of developing transgenic mice expressing the renilla/firefly luciferase dual reporter gene. Two-weeks old male mice divided into 2 groups and these groups were fed either a low PI diet or a normal control diet (normal: 0.5% Pi, low: 0.1% Pi) for 4 weeks. After 4 weeks of the diet, all the mice were sacrificed. Their lungs were harvested and analyzed by performing luciferase assay, Western blotting, kinase assay and immunohistochemistry. Our results demonstrate that low Pi affects the lungs of developing mice by disturbing protein translation, the cell cycle and the expression of fibroblast growth factor-2. These results suggest that optimally regulating Pi consumption may be important to maintain health.
Animals ; Blotting, Western ; Carrier Proteins/metabolism ; Immunohistochemistry ; Lung/drug effects/enzymology/*growth & development/metabolism ; Male ; Mice ; Mice, Transgenic ; Phosphoproteins/metabolism ; Phosphorus, Dietary/*administration & dosage ; Phosphorylation ; Phosphotransferases (Alcohol Group Acceptor)/metabolism ; Proto-Oncogene Proteins c-akt/metabolism ; Sodium-Phosphate Cotransporter Proteins, Type IIa/*metabolism