Incubation Of A549 Cells Research Articles

Size-fractionated ambient particulate matter induce toxicity: Oxidative potential, cytotoxic effect and inflammatory potential

Present study highlighted the importance of examining the toxicological profile of size-segregated particulate matter (PM) bound metals (Fe, Mn, Ni, Pb, Zn, Cu, Cr, Co, Cd) at urban site of Pune city, India. The total aerosol mass was composed of 61.2% and 38% fine and coarse particles, respectively with maximum distribution observed in 4.7–2.1 μm size mode. Elemental size distributions indicated the prime association of Fe, Mn and Zn with coarse sized PM, while remaining metals were predominantly associated with fine PM. Seasonal mass and elemental distribution profile of size-resolved PM was characterized with maximum concentration found in winter season. Enrichment factor analysis revealed the contribution of anthropogenic emissions to Co and Ni in fine mode while less enriched metals, Fe and Mn were allied with crustal and natural sources. Oxidative potential of particles in terms of Dithiothreitol (DTT) loss was found to be maximum in the size range of 4.7–1.1 μm with dominant contribution of PM bound metals (Fe, Cu, Cr, Mn, Ni, Pb, and Zn). On exposure to PM samples, prominent enhancement in the expression of cytokines (especially TNFα) as compared to the control has confirmed their inflammatory nature. Incubation of A549 cells with PM suspension (75 mg/ml) caused pronounced reduction (p < 0.01) in cell viability with significant morphological changes, associated with cell death. Respiratory deposition doses of PM in head region were found to be more impacted by coarse sized particles while contribution of fine PM was dominant in alveolar and tracheobronchial region, signifying serious health risks to the exposed population. In addition to the basic knowledge of toxicity mechanisms associated with size fractionated PM, these results together with the analysis of correlation between PM bound metals and biological assays will be relevant to better characterize the potential health risks and possible future mitigation strategies.

Human Blood Extracellular Vesicles Activate Transcription of NF-kB-Dependent Genes in A549 Lung Adenocarcinoma Cells.

Extracellular vesicles (EVs) produced by various cell types are heterogeneous in size and composition. Changes in the RNA sets of EVs in biological fluids are considered the basis for the development of new approaches to minimally invasive diagnostics and the therapy of human diseases. In this study, EVs were obtained from the blood of healthy donors by centrifugation, followed by ultracentrifugation. It was shown that EVs consist of several populations including small exosome-like vesicles and larger microvesicle-like particles. The composition of EVs' RNAs was determined. A549 lung adenocarcinoma cells were incubated with EV and the NGS analysis of differentially expressed genes was performed. During the incubation of A549 cells with EVs, the levels of mRNA encoding components for the NF-kB signaling pathway increased, as well as the expression of genes controlled by the NF-kB transcription factor. Overall, our results suggest that components of EVs trigger the NF-kB signaling cascade in A549 cells, leading to the transcription of genes including cytokines, adhesion molecules, cell cycle regulators, and cell survival factors. Our data provide insight into the interaction between blood EVs and human cells and can be used for designing new tools for the diagnosis and treatment of human diseases.

The liver X receptor agonist T0901317 reduces the inflammation of alveolar epithelial cells induced by polyhexamethylene guanidine through inhibition of the NFκB signaling pathway

BackgroundAs a kind of disinfectant, polyhexamethylene guanidine (PHMG) can cause pulmonary inflammation. In addition to liver X receptors (LXRs) playing an important role in cholesterol and lipid metabolism, it has also been found to be involved in inflammation in recent years. This article explores the role of LXRs agonist T0901317 in the inflammation of alveolar epithelial cells induced by PHMG.MethodsThe A549 human alveolar basal epithelial cell line was exposed to PHMG, T0901317, or the nuclear factor (NF)κB inhibitor BAY11-7082. The cell survival rate was used to determine the cytotoxicity of PHMG and T0901317 to A549 cells. Western blot analysis was used to determine the expression of proteins related to the LXRs and the NFκB signaling pathway. Enzyme-linked immunosorbent assay (ELISA) was conducted to examine the expression of inflammatory cytokines such as interleukin (IL)-8 and interleukin (IL)-6.ResultsIncubation of A549 cells with PHMG decreased the expression of LXRs-related proteins, reduced the expression of cellular IκB, increased the expression of nuclear NFκB, and increased the levels of the inflammatory cytokineIL-8 and IL-6. However, pretreatment with the LXR agonist T0901317 partially reversed the effects of PHMG. The effects of T0901317on NFκB signaling pathway was similar to that observed with the NFκB inhibitor BAY11-7082.ConclusionsThe LXRs agonist T0901317 may reduce the inflammation of alveolar epithelial cells induced by PHMG by inhibiting the NFκB signaling pathway.

Aspirin eugenol ester ameliorates paraquat-induced oxidative damage through ROS/p38-MAPK-mediated mitochondrial apoptosis pathway

Paraquat (PQ) is an effective and commercially important herbicide that is widely used worldwide. However, PQ is highly toxic and can cause various complications and acute organ damage. Aspirin eugenol ester (AEE) is a potential new compound with anti-inflammatory and antioxidant stress pharmacological activity. The present study was to reveal the therapeutic effects and the protective effect of AEE against PQ-induced acute lung injury (ALI) with the help of PQ-induced oxidative damage in A549 cells and PQ-induced lung injury in rats. AEE might have no significant therapeutic effect on PQ-induced lung injury in rats. However, AEE had a significant protective effect on PQ-induced lung injury in rats. AEE pretreatment significantly reduced the stimulatory effect of PQ on malondialdehyde (MDA), the inhibitory effect of PQ on catalase (CAT) activity, superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, the ratio of GSH/GSSH, the activity of caspase-3 and the overexpression of p38 mitogen-activated protein kinase (MAPK) phosphorylation in vivo. In vitro, A549 cells were treated with 250 μM PQ for 24 h. Incubation of A549 cells with PQ led to apoptosis, and increased the level of superoxide anions, reactive oxygen species (ROS), malondialdehyde and the activity of caspase-3 and up-regulation of phosphorylated p38-MAPK, reduced mitochondrial membrane potential (ΔΨm) and the activity of SOD. However, after 24 h on AEE pretreatment of A549 cells, the above-mentioned adverse reactions caused by PQ were significantly alleviated. In addition, AEE pretreatment reduced p38-MAPK phosphorylation in PQ-treated A549 cells. SB203580, the specific p38-MAPK inhibitor, and p38-MAPK shRNA attenuated the activation of the p38-MAPK signaling pathway. N-acetylcysteine (NAC) reduced the level of phosphorylated p38-MAPK and the production of intracellular ROS and inhibited apoptosis. The results showed that AEE may inhibit PQ-induced cell damage through ROS/p38-MAPK-mediated mitochondrial apoptosis pathway.

MUC1 mediates Pneumocystis murina binding to airway epithelial cells.

Previous studies have shown that Pneumocystis binds to pneumocytes, but the proteins responsible for binding have not been well defined. Mucins are the major glycoproteins present in mucus, which serves as the first line of defence during airway infection. MUC1 is the best characterised membrane-tethered mucin and is expressed on the surface of most airway epithelial cells. Although by electron microscopy Pneumocystis primarily binds to type I pneumocytes, it can also bind to type II pneumocytes. We hypothesized that Pneumocystis organisms can bind to MUC1 expressed by type II pneumocytes. Overexpression of MUC1 in human embryonic kidney HEK293 cells increased Pneumocystis binding, while knockdown of MUC1 expression by siRNA in A549 cells, a human adenocarcinoma-derived alveolar type II epithelial cell line, decreased Pneumocystis binding. Immunofluorescence labelling indicated that MUC1 and Pneumocystis were co-localised in infected mouse lung tissue. Incubation of A549 cells with Pneumocystis led to phosphorylation of ERK1/2 that increased with knockdown of MUC1 expression by siRNA. Pneumocystis caused increased IL-6 and IL-8 secretion by A549 cells, and knockdown of MUC1 further increased their secretion in A549 cells. Taken together, these results suggest that binding of Pneumocystis to MUC1 expressed by airway epithelial cells may facilitate establishment of productive infection.

AUTOPHAGY REGULATION BY RUBELLA VIRUS

Aim. Some viruses can subvert host defense mechanism, autophagy, to their own benefit. We analysed the effect of Rubella virus (RV) infection on autophagy in human alveolar epithelial cells A549. Materials and methods. Cells were infected with the wild type and lab-attenuated strain, C-77w and C-77a, respectively, with a multiplicity of infection of 1.0, in parallel, the expression level of genes encoding Beclin1, Atg5, Rab7, and p62 (SQSTM1) proteins participating in different steps of autolysosome formation was measured. To investigate the role of autophagy on RV replication cycle, we measured the amount of infectious RV particles, together with the viral RNA in supernatants and cell lysates, after incubation of A549 cells with wild type or attenuated strain in the presence of the autophagy inhibitor, Bafilomycin A1, or inducer, Rapamycin. Results. The significant increase in Beclin1 and Atg5 gene expression at 24-48 (for the wild type) and 24-72 (for the attenuated type) hours after infection was observed, while significant induction of either Rab7 or SQSTM1 gene expression was not noticed. This effect was correlated with more delayed increase of IFNβ expression and IFNβ-mediated pro-apoptotic gene expression leading to apoptotic cell death 72-96 hours after infection. Moreover, Bafilomycin A1 diminished the RV infection non significantly, as evidenced by the RT-qPCR and plaque assay, while Rapamycin increased the amount of infectious RV particles released by the infected cells more dramatically with wild type comparing with attenuated strain. Conclusion. Thus, we hypothesized that RV can use an antiviral mechanism to prevent degradation and ensure its replication, differentially regulating the process of autophagy, by stimulating the initiation and suppression of later steps.

Ferrous glycinate regulates cell energy metabolism by restrictinghypoxia-induced factor-1α expression in human A549 cells

Iron or oxygen regulates the stability of hypoxia inducible factor-1α (HIF-1α). We investigated whether ferrous glycinate would affect HIF-1α accumulation, aerobic glycolysis and mitochondrial energy metabolism in human A549 lung cancer cells. Incubation of A549 cells with ferrous glycinate decreased the protein levels of HIF-1α, which was abrogated by proteosome inhibitor, or prolyl hydroxylase inhibitor. The addition of ferrous glycinate decreased protein levels of glucose transporter-1, hexokinase-2, and lactate dehydrogenase A, and decreased pyruvate dehydrogenase kinase-1 (PDK-1) and pyruvate dehydrogenase (PDH) phosphorylation in A549 cells. Ferrous glycinate also increased the expression of the mitochondrial transcription factor A (TFAM), and the mitochondrial protein, cytochrome c oxidase (COX-IV). Silencing of HIF-1α expression mimicked the effects of ferrous glycinate on PDK-1, PDH, TFAM and COX-IV in A549 cells. Ferrous glycinate increased mitochondrial membrane potential and ATP production in A549 cells. These results suggest that ferrous glycinate may reverse Warburg effect through down regulating HIF-1α in A549 cells.

Hinokitiol Inhibits Migration of A549 Lung Cancer Cells via Suppression of MMPs and Induction of Antioxidant Enzymes and Apoptosis

Hinokitiol, a natural monoterpenoid from the heartwood of Calocedrus formosana, has been reported to have anticancer effects against various cancer cell lines. However, the detailed molecular mechanisms and the inhibiting roles of hinokitiol on adenocarcinoma A549 cells remain to be fully elucidated. Thus, the current study was designed to evaluate the effect of hinokitiol on the migration of human lung adenocarcinoma A549 cells in vitro. The data demonstrates that hinokitiol does not effectively inhibit the viability of A549 cells at up to a 10 µM concentration. When treated with non-toxic doses (1–5 µM) of hinokitiol, the cell migration is markedly suppressed at 5 µM. Hinokitiol significantly reduced p53 expression, followed by attenuation of Bax in A549 cells. A dose-dependent inhibition of activated caspase-9 and -3 was observed in the presence of hinokitiol. An observed increase in protein expression of matrix metalloproteinases (MMPs) -2/-9 in A549 cells was significantly inhibited by hinokitiol. Remarkably, when A549 cells were subjected to hinokitiol (1–5 µM), there was an increase in the activities of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) from the reduction in cells. In addition, the incubation of A549 cells with hinokitiol significantly activated the cytochrome c expression, which may be triggered by activation of caspase-9 followed by caspase-3. These observations indicate that hinokitiol inhibited the migration of lung cancer A549 cells through several mechanisms, including the activation of caspases-9 and -3, induction of p53/Bax and antioxidant CAT and SOD, and reduction of MMP-2 and -9 activities. It also induces cytochrome c expression. These findings demonstrate a new therapeutic potential for hinokitiol in lung cancer chemoprevention.

IL-1\u03b2 is a key cytokine that induces trypsin upregulation in the influenza virus\u2013cytokine\u2013trypsin cycle

Severe influenza is characterized by a cytokine storm, and the influenza virus–cytokine–trypsin cycle is one of the important mechanisms of viral multiplication and multiple organ failure. The aim of this study was to define the key cytokine(s) responsible for trypsin upregulation. Mice were infected with influenza virus strain A/Puerto Rico/8/34 (H1N1) or treated individually or with a combination of interleukin-1β, interleukin-6, and tumor necrosis factor α. The levels of these cytokines and trypsin in the lungs were monitored. The neutralizing effects of anti-IL-1β antibodies on cytokine and trypsin expression in human A549 cells and lung inflammation in the infected mice were examined. Infection induced interleukin-1β, interleukin-6, tumor necrosis factor α, and ectopic trypsin in mouse lungs in a dose- and time-dependent manner. Intraperitoneal administration of interleukin-1β combined with other cytokines tended to upregulate trypsin and cytokine expression in the lungs, but the combination without interleukin-1β did not induce trypsin. In contrast, incubation of A549 cells with interleukin-1β alone induced both cytokines and trypsin, and anti-interleukin-1β antibody treatment abrogated these effects. Administration of the antibody in the infected mice reduced lung inflammation area. These findings suggest that IL-1β plays a key role in trypsin upregulation and has a pathological role in multiple organ failure.

Identification of Helicobacter pylori VacA in human lung and its effects on lung cells

ObjectivePrior reports suggested that infection with Helicobacter pylori was associated with respiratory diseases; pathogenetic mechanisms however, were not defined. We tested the hypothesis that VacA, an exotoxin of H. pylori, a gastric pathogen, was aspirated into the lung and could stimulate secretion of inflammatory cytokines by lung epithelial cells. MethodsThe presence of VacA was determined by immunohistochemistry in surgical lung biopsy tissue samples from 72 patients with interstitial pneumonia. The effects of VacA on A549 human alveolar epithelial adenocarcinoma cells and normal human bronchial epithelial cells were determined. After incubation with VacA, the secretions of cytokines were measured by Multiplex Luminex® Assays. ResultsVacA was detected with anti-VacA antibodies in bronchial epithelial cells and alveolar epithelial cells from 10 of 72 patients with interstitial pneumonia. VacA was more prevalent in lungs of patients with collagen vascular disease-associated interstitial pneumonia than in those of patients with idiopathic pulmonary fibrosis, nonspecific interstitial pneumonia and cryptogenic organizing pneumonia. Incubation of A549 cells and normal human bronchial epithelial cells with VacA for 24 h was cytotoxic, and resulted in vacuolation. VacA induced interleukin-8 production by A549 cells and normal human bronchial epithelial cells and interleukin-6 production by A549 cells. Based on multiplex screening, interleukin-8 and interleukin-6 were the primary secretory products induced by VacA. ConclusionsH. pylori VacA is present in human lung and can induce interleukin-8 and interleukin-6 production by human lung cells. VacA could have a role in the pathogenesis of respiratory diseases by its cytotoxic effects and by inducing the secretion of interleukin-8 and interleukin-6 by targeted airway epithelial cells.

Annona muricata leaves induced apoptosis in A549 cells through mitochondrial-mediated pathway and involvement of NF-κB.

BackgroundAnnona muricata leaves have been reported to have antiproliferative effects against various cancer cell lines. However, the detailed mechanism has yet to be defined. The current study was designed to evaluate the molecular mechanisms of A. muricata leaves ethyl acetate extract (AMEAE) against lung cancer A549 cells.MethodsThe effect of AMEAE on cell proliferation of different cell lines was analyzed by MTT assay. High content screening (HCS) was applied to investigate the suppression of NF-κB translocation, cell membrane permeability, mitochondrial membrane potential (MMP) and cytochrome c translocation from mitochondria to cytosol. Reactive oxygen species (ROS) formation, lactate dehydrogenase (LDH) release and activation of caspase-3/7, -8 and -9 were measured while treatment. The western blot analysis also carried out to determine the protein expression of cleaved caspase-3 and -9. Flow cytometry analysis was used to determine the cell cycle distribution and phosphatidylserine externalization. Quantitative PCR analysis was performed to measure the gene expression of Bax and Bcl-2 proteins.ResultsCell viability analysis revealed the selective cytotoxic effect of AMEAE towards lung cancer cells, A549, with an IC50 value of 5.09 ± 0.41 μg/mL after 72 h of treatment. Significant LDH leakage and phosphatidylserine externalization were observed in AMEAE treated cells by fluorescence analysis. Treatment of A549 cells with AMEAE significantly elevated ROS formation, followed by attenuation of MMP via upregulation of Bax and downregulation of Bcl-2, accompanied by cytochrome c release to the cytosol. The incubation of A549 cells with superoxide dismutase and catalase significantly attenuated the cytotoxicity caused by AMEAE, indicating that intracellular ROS plays a pivotal role in cell death. The released cytochrome c triggered the activation of caspase-9 followed by caspase-3. In addition, AMEAE-induced apoptosis was accompanied by cell cycle arrest at G0/G1 phase. Moreover, AMEAE suppressed the induced translocation of NF-κB from cytoplasm to nucleus.ConclusionsOur data showed for the first time that the ethyl acetate extract of Annona muricata inhibited the proliferation of A549 cells, leading to cell cycle arrest and programmed cell death through activation of the mitochondrial-mediated signaling pathway with the involvement of the NF-kB signalling pathway.

Simvastatin prevents proliferation and bone metastases of lung adenocarcinoma in vitro and in vivo

To explore the mechanism about how HMG-CoA reductase (HMGR) inhibitor inhibit proliferation and bone metastases of lung adenocarcinoma in vitro and in vivo. The HMGR inhibitor simvastatin, human lung cancer cell line A549 and Balb/c nude mouse were used in this study. The mice were randomly divided into 2 groups: control group (0.9% NaCl solution, i.v.) and simvastatin group (5mg/kg simvastatin, i.v.). A scratch assay using A549 cell monolayer was also tested. An invasion assay using collagen-coated membrane in trans-wells was applied to evaluate the effect of simvastatin on the metastatic potential of A549 cells in vitro. The expressions of CD44, PUMA, P53, MMP2 and MMP9 were determined by real-time PCR and western blotting; the phosphorylation status of MAPK/ERK signaling parthway was investigated by western blot. . Compared with the control group, the migration of A549 cells in simvastatin-treated group was markedly inhibited (p ≤ 0.01). Untreated A549 cells showed marked invasion, while simvastatin significantly inhibited the invasion of tumor cells (p ≤ 0.001). Incubation of A549 cells with simvastatin significantly reduced the levels of CD44, MMP2 and MMP9 (p <0.01), while significantly increased p53 (p < 0.01). Simvastatin significantly inhibits tumor growth and bone metastasis in lung cancer xenograft mouse model, simvastatin can inhibit the kinase phosphorylation inMAPK/ERK signaling parthway. The HMGR inhibitor simvastatin prevents proliferation and osteolytic bone metastases of lung adenocarcinoma cells in vitro and vivo. Its mechanism may be associated with regulation of CD44, P53, MMP family and inactivation of MAPK/ERK signaling parthway.

Inhibition of mitogen activated protein kinases increases the sensitivity of A549 lung cancer cells to the cytotoxicity induced by a kava chalcone analog

We are interested in investigating the biological activity of chalcones, a major class of compounds found in the beverage kava, in order to develop potent and selective chemopreventive candidates. Consumption of kava in the South Pacific Islands is inversely correlated with cancer incidence, even among smokers. Accordingly, chalcones have anti-cancer activities in animal and cell culture models. To investigate signaling pathways that affect chalcone action we studied a potent analog, (E)-3-(3-hydroxy-4-methoxyphenyl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (chalcone-24). Chalcone-24 was selected from a series of chalcone analogs that were synthesized based on the structures derived from flavokawain compounds found in kava, and screened in A549 lung cancer cells for induction of cytotoxicity and inhibition of NF-κB, a transcription factor associated with cell survival. Incubation of A549 cells with chalcone-24 resulted in a dose-dependent inhibition of cell viability, inhibition of NF-κB, activation of caspases, and activation of extracellular signal regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK); ERK1/2 and JNK are mitogen activated protein kinases that play central roles in regulating cell fate. Pharmacological inhibitors of ERK1/2 or JNK increased the sensitivity of A549 cells to chalcone-24-induced cytotoxicity, without affecting NF-κB or caspase activity. These results will help refine the synthesis of chalcone analogs to maximize the combination of actions required to prevent and treat cancer.

Seawater induces apoptosis in alveolar epithelial cells via the Fas/FasL-mediated pathway

Our previous study showed that seawater can cause lung tissue cell apoptosis; in the present study, the immunohistochemistry and Western blot analysis results demonstrated that Fas, FasL, and cleaved caspase-8 and caspase-3 were up-regulated in the rat lungs exposed to seawater. We found that seawater-induced human lung alveolar epithelial A549 cell apoptosis was concentration and time dependent. Moreover, seawater increased the expression of Fas, FasL, and cleaved caspase-8 and caspase-3 in A549 cells. The incubation of A549 cells in the presence of FasL-neutralising antibody (NOK-2) or caspase-8 inhibitor (Z-IETD-FMK) resulted in a decrease of seawater-induced cell apoptosis. NOK-2 inhibited Fas/FasL interaction and reduced the cleavage of caspase-8 and caspase-3, and Z-IETD-FMK blocked caspase-8 and caspase-3 activation. Seawater similarly produced a significant increase in rat alveolar type II cell apoptosis and expression of Fas and cleaved caspase-8. In summary, the Fas/FasL pathway involved in alveolar epithelial cell (AEC) apoptosis could be important in the pathogenesis of seawater-induced acute lung injury (SW-ALI).

Investigation of IL-6 Effects on SP-A Expression in A549 Lung Cell Line

ABSTRACTInterleukin-6 (IL-6) is a multifunctional cytokine that is important in inflammatory processes, cell differentiation and growth.Pulmonary surfactant is a protein-lipid complex, which reduce surface tension at the alveolar air-liquid interface, thereby preventing lung collapse. Surfactant protein A (SP-A) is the most abundant of four surfactant proteins (SP-A, SP-B, SP-C and SP-D). It binds to alveolar macrophages, stimulates their chemotaxis and serves as an opsonin in the phagocytosis.Low SP-A levels are associated with increased inflammation in the lung. In the absence of infection SP-A inhibited IL-6 production. In infected macrophages, SP-A augmented IL-6 production. In humans, SP-A levels are altered by a number of disease states. In some of them there is increased levels of SP-A in the bronchoalveolar lavage fluid.Here we investigate presence/absence of correlation between increased levels of IL-6 and production of SP-A from A549 lung cell line. Our results suggest that incubation of A549 cells with IL-6 for different time changes significantly the expression levels of SP-A.

Angelica sinensis suppresses human lung adenocarcinoma A549 cell metastasis by regulating MMPs/TIMPs and TGF-β1

In this study we investigated the potential effects of Angelica sinensis on the growth and metastasis in human lung adenocarcinoma A549 cells. Invitro the Cck-8 assays showed that Angelica sinensis had weak antiproliferative effect on A549 cells only at high concentration. The cell adhesion assay showed that Angelica sinensis decreased the adhesive ability of A549 cells in a dose- and time-dependent manner. Transwell invasion and migration assay showed that Angelica sinensis reduced the invasive and migratory abilities of A549 cells in a dose-dependent manner. Invivo the animal experiments showed that Angelica sinensis suppressed lung metastasis of nude mice at high concentration. Then, we attempted to clarify the mechanisms of anti-metastatic activities of Angelica sinensis. The results showed Angelica sinensis inhibited the enzymatic activity of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), it involved the down-regulation of the expressions of MMP-2 and MMP-9 at both the protein and mRNA levels, which may be associated with Angelica sinensis suppressing the expression of TGF-β1. It also involved the increase of the tissue inhibitors of metalloproteinases TIMP-2, but TIMP-1 decreased upon incubation of A549 cells with Angelica sinensis. The results suggest that Angelica sinensis might exert anti-growth and anti-metastasis activity against lung cancer cells through the decrease of MMP-2, MMP-9, TGF-β1 and TIMP-1 and increase of TIMP-2.

Abstract 3987: Src regulates inhibitor of differentiation 1 (Id1) via c-Myc induced repression of microRNA-29b: Implications for invasion of lung cancer cells and their resistance against Src inhibitors

Abstract Background: Src and Id1 mediate cancer cell invasion and are frequently co-expressed in non-small cell lung cancer (NSCLC). We previously demonstrated that Src regulates Id1 in human lung cancer cells. MicroRNAs (miRNAs) are noncoding RNAs that regulate gene expression by inducing translational inhibition or cleavage of their target mRNAs. The current study aimed at identifying miRNAs controlled by Src that target Id1, and to test if modulation of these miRNAs and Id1 in NSCLC cells leads to resistance against Src inhibitors. Methods: The study included the following human lung cancer cell lines: A549, H460, H1299, H820, HCC827. Cells were incubated with the Src inhibitors Saracatinib and Dasatinib and miRNA was extracted. To assess miRNA expression profiles, we used TaqMan® Array MicroRNA Cards (Applied Biosystems). Western Blotting was performed using antibodies for Src, phospho-Src, Id1, c-Myc, active beta-Catenin and Actin. Id1 and miR-29b transcript levels were measured using real-time quantitative RT-PCR. Lentiviral vectors expressing pre-miR-29b, anti-sense miR-29b, Id1 and c-Myc were used. Migration was tested with wound healing assays. For invasion matrigel coated membranes for transwell assays were used. Formalin-fixed and paraffin-embedded adenocarcinoma samples and matched lung tissue from 23 patients were used for miRNA expression analysis. Results: Upon incubation of A549 cells with Saracatinib, miR-29b was the most highly upregulated miRNA with a predicted binding site in the Id1 3’UTR. Indeed, Id1 3’UTR luciferase reporter assays revealed direct binding of miR-29b to the Id1 3’UTR, but not to a mutated Id1 3’UTR. Anti-miR-29b enhanced Id1 mRNA and protein levels and significantly increased cell migration and invasion (p=0.0006). Anti-miR-29b or Id1 overexpression abolished the effects of Src inhibitors on invasion and migration. In contrast, transfection with pre-miR-29b suppressed Id1 and significantly reduced cell migration and invasion (p&amp;lt;0.00001). Overexpression of c-Myc repressed the level of miR-29b and induced the expression of Id1. Saracatinib and Dasatinib decreased active beta-Catenin, c-Myc and Id1 levels, and increased miR-29b levels in a dose-dependent manner. In 19 of 23 human lung adenocarcinoma biopsies, miR-29b was significantly downregulated compared with matched normal lung tissue (p=0.031). miR-29b was a strong prognostic factor for event-free (p=0.003) and overall survival (p=0.04) Conclusions: These results demonstrate that Id1 is a direct target of miR-29b, which in turn is regulated by Src, active beta-Catenin and c-Myc. Therefore, miR-29b is involved in lung cancer cell migration and invasion. Furthermore, miR-29b is downregulated in human lung adenocarcinomas, and may be involved in the resistance of lung cancer cells against Src kinase inhibitors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3987. doi:10.1158/1538-7445.AM2011-3987

Purinergic Receptor-mediated Rapid Depletion of Nuclear Phosphorylated Akt Depends on Pleckstrin Homology Domain Leucine-rich Repeat Phosphatase, Calcineurin, Protein Phosphatase 2A, and PTEN Phosphatases

Akt is an important oncoprotein, and data suggest a critical role for nuclear Akt in cancer development. We have previously described a rapid (3-5 min) and P2X7-dependent depletion of nuclear phosphorylated Akt (pAkt) and effects on downstream targets, and here we studied mechanisms behind the pAkt depletion. We show that cholesterol-lowering drugs, statins, or extracellular ATP, induced a complex and coordinated response in insulin-stimulated A549 cells leading to depletion of nuclear pAkt. It involved protein/lipid phosphatases PTEN, pleckstrin homology domain leucine-rich repeat phosphatase (PHLPP1 and -2), protein phosphatase 2A (PP2A), and calcineurin. We employed immunocytology, immunoprecipitation, and proximity ligation assay techniques and show that PHLPP and calcineurin translocated to the nucleus and formed complexes with Akt within 3 min. Also PTEN translocated to the nucleus and then co-localized with pAkt close to the nuclear membrane. An inhibitor of the scaffolding immunophilin FK506-binding protein 51 (FKBP51) and calcineurin, FK506, prevented depletion of nuclear pAkt. Furthermore, okadaic acid, an inhibitor of PP2A, prevented the nuclear pAkt depletion. Chemical inhibition and siRNA indicated that PHLPP, PP2A, and PTEN were required for a robust depletion of nuclear pAkt, and in prostate cancer cells lacking PTEN, transfection of PTEN restored the statin-induced pAkt depletion. The activation of protein and lipid phosphatases was paralleled by a rapid proliferating cell nuclear antigen (PCNA) translocation to the nucleus, a PCNA-p21(cip1) complex formation, and cyclin D1 degradation. We conclude that these effects reflect a signaling pathway for rapid depletion of pAkt that may stop the cell cycle.

Effect of endotoxin on COX-2 dependent proliferation of NSCLC cells: Role of CD14, TLRs, and EGFR signaling

e22190 Background: Bacterial infections are common in NSCLC and growing evidence indicates that inflammation is contributing to cancer growth. Against this background, we investigated the effect of the bacterial cell wall components LPS on the proliferation of the NSCLC cell line A549. Methods: Proliferation of A549 cells was quantified by MTS-assay. PGE2 production was analyzed by ELISA and COX-2 mRNA was quantified by RT-PCR. Results: Incubation of A549 cells with LPS induced a time- and dose-dependent proliferation of A549 cells. Pro-proliferative effects of endotoxin could be inhibited by neutralizing antibodies targeting CD14 and TLR4, but not by inhibition of TLR2. Interestingly, interference with COX-2 activity by the specific inhibitor NS-398 strongly attenuated the LPS-induced tumor cell proliferation. In parallel, large amounts of COX-2 dependent PGE2were released by LPS-stimulated A549 cells. Moreover, enhanced transcription of COX-2 specific mRNA was detected in LPS-stimulated A549 cells. Interestingly, EGFR signaling was obviously involved in LPS-induced tumor cell proliferation and PGE2 release, as both effects could be inhibited by the neutralizing EGFR-antibody cetuximab. Conclusions: We conclude that LPS induces COX-2 dependent proliferation of A549 cells in a CD14, TLR4, and EGFR dependant manner. These effects might contribute to pathogen induced tumor proliferation in NSCLC. No significant financial relationships to disclose.

α-Hederin, but Not Hederacoside C and Hederagenin fromHedera helix, Affects the Binding Behavior, Dynamics, and Regulation of β2-Adrenergic Receptors

Hederacoside C, alpha-hederin, and hederagenin are saponins of dry extracts obtained from the leaves of ivy (Hedera helix L.). Internalization of beta(2)-adrenergic receptor-GFP fusion proteins after stimulation with 1 microM terbutaline was inhibited by preincubation of stably transfected HEK293 cells with 1 microM alpha-hederin for 24 h, whereas neither hederacoside C nor hederagenin (1 microM each) influenced this receptor regulation. After incubation of A549 cells with 5 nM Alexa532-NA, two different diffusion time constants were found for beta(2)AR-Alexa532-NA complexes by fluorescence correlation spectroscopy. Evaluation of the autocorrelation curve revealed diffusion time constants: tau(bound1) = 1.4 +/- 1.1 ms (n = 6) found for receptor-ligand complexes with unrestricted lateral mobility, and tau(bound2) = 34.7 +/- 14.1 ms (n = 6) for receptor-ligand complexes with hindered mobility. The distribution of diffusion time constants was 24.3 +/- 2.5% for tau(bound1) and 8.7 +/- 4.3% for tau(bound2) (n = 6). A549 cells pretreated with 1 microM alpha-hederin for 24 h showed dose-dependent alterations in this distribution with 37.1 +/- 5.5% for tau(bound1) and 4.1 +/- 1.1% for tau(bound2). Simultaneously, the level of Alexa532-NA binding was significantly increased from 33.0 +/- 6.8 to 41.2 +/- 4.6%. In saturation experiments, alpha-hederin did not influence the beta(2)-adrenergic receptor density (B(max)), whereas the K(D) value for Alexa532-NA binding decreased from 36.1 +/- 9.2 to 24.3 +/- 11.1 nM. Pretreatment of HASM cells with alpha-hederin (1 microM, 24 h) revealed an increased intracellular cAMP level of 13.5 +/- 7.0% under stimulating conditions. Remarkably, structure-related saponins like hederacoside C and hederagenin did not influence either the binding behavior of beta(2)AR or the intracellular cAMP level.