ObjectiveTo observe the effects of A549 cells under hypoxicconditions on the migration of human umbilical vein endothelial cells (HUVECs) and microvascular formation. MethodsAfter cultured for 24 h in normoxia condition(21% O2),hypoxia condition (2% O2),and anaerobic condition (0% O2),respectively,morphology of A549 cells was observed with inverted phase contrast microscope,proliferation was detected by MTT assay,and intracellular hypoxia-inducible factor-1α (HIF-1α) protein was detected by immunocyto-chemical technique,for determining whether the hypoxia model is successful. Then A549 cells' supernatant in the normoxic group,the hypoxia group and HUVECs culture medium were taken to intervene HUVECs. The migration of HUVECs was observed with cell scratch test,pseudopodia formation of HUVECs was observed with microfilament green fluorescent staining method,and blood vessel formation was observed with three-dimensional culture techniques in vitro. ResultsCompared with the normoxic group,the growth of A549 cells was better in the hypoxia group with more proliferation,and was poor in the anaerobic group with decreased number of cells. A549 cells in the hypoxia group and the anaerobic group both expressed HIF-1α protein,which was more obvious in the anaerobic group. Compared with the HUVECs supernatant intervention group,the hypoxia supernatant intervention group and the normoxic supernatant intervention group both had varying degrees of migration,pseudopodia structure formation and vascular lumen sample structure formation,which were more obvious in the former group. ConclusionA549 cells in hypoxic environment grow very well,proliferated significantly,but anaerobic environment is not conducive to the growth of A549 cells which found to be apoptosis. A549 cells in hypoxic environment can promote HUVECs migration,pseudopodia formation and angiogenesis.
Objective To study the effect of nontypeable Hemophilus influenzae(NTHi) strain ATCC49247 on proinflammatory cytokines expression of human A549 lung epithelial cell line. Methods Confluent A549 cells were co-incubated with NTHi, NTHi+Erythromycin(10 mg/L), NTHi+Gentamicin(100 mg/L), and NTHi+Dexamethasone(100 μmol/L),and nuclear factor kappa B(NF-κB) inhibitor primed cells were co-incubated with NTHi for 24 h. Then levels of interleukin-8（IL-8） and tumor necrosis factor-α(TNF-α) in the supernatant was assayed by enzyme-linked immunosorbent assay(ELISA) and the expression of intercellular adhesion molecule-1(ICAM-1) in cells was detected by immunohistochemistry staining. Results A549 cells were transformed and died after co-intubated with NTHi for 24 h. NTHi induced A549 cells to release significantly greater amounts of IL-8, which was inhibited by NF-κB inhibitor pyrrolidine dithiocarbamate（PDTC）. Incubating of A549 cells with NTHi significantly induced release of IL-8 and the expression of ICAM-1, which was blocked by erythromycin and dexamethasone and not by gentamicin. TNF-α was not detected in all circumstances. Conclusions NTHi can increase significantly the release and expression of proinflammatory cytokines through NF-κB pathway. Antibacterial drug erythromycin also has anti-inflammatory effect.
Objective To investigate the radiation-sensitizing effects of Ku80 silencing by siRNA interference for A549 lung cancer cells. Methods The sequences of Ku80 siRNA and negative siRNA were chemically synthesized and transfected into A549 lung cancer cells by lipofectamine. RT-PCR and Western bolt analysis were used to determine Ku80 gene expression. The transfected cells in culture dishes were irradiated with X ray at doses of 2 Gy, 4 Gy, 6 Gy, 8 Gy, 10 Gy, respectively. Once all treatments were completed, the cells were processed with the colony formation assay. Results RT-PCR detection showed that Ku80 mRNA levels in A549 lung cancer cells were reduced after transfected with Ku80 siRNA at 24 h, 48 h and 72 h time points. Western blot analysis showed that Ku80 protein content decreased at 48 h and 72 h time points compared with the control group ( P lt; 0. 05 ) . Cloning formation assay indicated that radiosensitivity of A549 lung cancer cells was enhanced after transfected with Ku80 siRNA. Conclusion Ku80 siRNA can effectively inhibit Ku80 gene expression of A549 lung cancer cells, and therefore enhance its radiosensitivity.
Objective To identify the effects of single immunoglobin IL-1 receptor related protein （SIGIRR） on inflammation induced by high mobility group box 1 （HMGB1） in A549 derived from human alveolar epithelial cells. Methods Eukaryotic expression vectors pCDNA3.1（+） constructed with SIGIRR cDNA were transiently transfected into A549 cells，in which SIGIRR was forced to be over-expressed. Western blot and RT-PCR were applied to detect the expression level of SIGIRR after transfection. After the stimulation by HMGB1，the transcriptional activity of NF-κB in A549 cells was detected by dual-luciferase reporter assay system，and the protein levels of inflammatory cytokine TNF-α and IL-1β were measured by ELISA. Results The expression level of SIGIRR increased significantly in A549 cells transfected with SIGIRR vectors. The transcriptional activity of NF-κB was enhanced obviously after HMGB1 treatment in A549 cells by dual-luciferase reporter assay system，while the transfection of SIGIRR vectors decreased the activity. The protein levels of TNF-α and IL-1β were down-regulated in A549 cells over-expressing SIGIRR after HMGB1 stimulation compared with the non-transfected cells. Conclusions Up-regulated SIGIRR expression can inhibit HMGB1-induced proinlammatory cytokine release in A549 cells such as TNF-α and IL-1β. The transcriptional activity of NF-κB is dampened by SIGIRR transfection，implying that the anti-inflammatory effects of SIGIRR may be involved in the regulation of NF-κB.
Objective To observe the genotype distribution of Haemophilus parainfluenzae from patients with acute exacerbations of chronic obstructive pulmonary disease ( AECOPD) and their effects on A549 cells. Methods 80 hospitalized patients with AECOPD in our hospital were enrolled. Haemophilus parainfluezae were collected by sputum culture and genotyped, then inoculated with cell line A549. IL-6 and IL-8 concentrations in the supernatant were detected and cell morphology was observed at different time points. Results The patients were divided into three groups according to their symptoms. 15 Haemophilus parainfuenzae strains were collected and the positive culture rate between type 1 and type 3 COPD patients were statistically different. The concentrations of IL-6 and IL-8 were both significantly higher than control and increased as time passed. 4 genotypes were got by random amplification of polymorphic DNA ( RAPD) . In RAPD Ⅲ group, the IL-8 concentration was higher at 12h and 24h than others. No morphologic change was found in the cells inoculated with Haemophilus parainfuenzae by microscope after fixing. Conclusions Positive culture rate of Haemophilus parainfuenzae was different in different COPD groups according to symptoms. Haemophilus parainfuenzae can stimulate a cytokine response in A549 cells, maybe one of the pathogens of AECOPD, especially the RAPDⅢ type. Haemophilus parainfuenzae is not an intracellular bacteria.
ObjectiveTo investagte the effects of single immunoglobin IL-1 receptor related protein (SIGIRR) on inflammation induced by cigarette smoke extract (CSE) in A549 cells derived from mouse alveolar epithelial cells. MethodsA549 cells were divided into a control group and an over-expressed SIGIRR group. Eukaryotic expression vectors pcDNA3.1(+) constructed with SIGIRR cDNA were transiently transfected into A549 cells, in which SIGIRR was forced to be over-expressed. The expression level of SIGIRR after transfection was detected with Western blot and RT-PCR method. After stimulated by CSE in both groups, the protein level of IL-6 was detected by ELISA, the transcriptional activity of cyclooxygenase-2(COX-2) was detected by dual-luciferase reporter assay system, and the release of reactive oxygen species (ROS) was measured by chemiluminescence method. ResultsThe expression level of SIGIRR increased significantly in A549 cells transfected with SIGIRR vectors. The COX-2 expression and the levels of ROS and IL-6 were significantly increased in the control group after CSE stimulation. Nevertheless, in the over-expressed SIGIRR group, the COX-2 expression and the release of ROS was reduced while the protein level of IL-6 was down-regulated compared with the control group(P < 0.05). ConclusionsUp-regulated SIGIRR expression can suppress the levels of ROS, COX-2 and IL-6 in A549 cells stimulated by CSE. It suggests that SIGIRR can inhibit airway inflammation caused by smoking.
Objective To study the differences in gene expression in A549 cells transfected with Forkhead box protein O1(FOXO1),and provide clues to further exploring the mechanism of FOXO1 in acute lung injury. Methods After using TNF-α to stimulate A549 cells,the eukaryotic expression vector GV230-FOXO1 was transfected into A549 cells by using lipofectamine transfection reagent.The RNA was isolated and differentially expressed genes were screened with high-throughout DNA microarray. Results The eukaryotic expression vector GV230-FOXO1 was successfully constructed and verified.High quality mRNA was isolated and prepared for microarray screening,which passed RNA quality control.The DNA microarray data indicated that 317 genes were up-regulated and 237 genes were down-regulated in A549 cells transfected with FOXO1.The function of these differentially expressed genes involved in many aspects,such as proliferation,apoptosis and differentiation. Conclusions Differentially expressed genes in A549 cells transfected with FOXO1 can be successfully screened by using DNA microarray.FOXO1 may influence the progression of the disease by changing the level of cell proliferation,apoptosis and differentiation in acute lung injury.
Objective To evaluate the expression of reactive oxygen species (ROS), glutataione (GSH), total superoxide dismutase (T-SOD), total antioxidation capacity (T-AOC), thioredoxin reductase (TrxR) under the intervention of hedysarum polysaccharides-1 (HPS-1) in A549 cells. Methods After treated by HPS-1 in different doses (50 mg/L, 100 mg/L, 200 mg/L, respectively), the viability of cell lines was detected by MTT method under microscope. The apoptosis of cell lines was detected by flow cytometry (FCM). The expressions of ROS, GSH, T-SOD, T-AOC, and TrxR in cell supernatant were measured by chemiluminescence method. Results Determined by MTT/FCM/ELISA, the results showed that different doses of HPS-1 could inhibit the proliferation and promote the apoptosis of A549 cells (allP<0.05). The expression levels of GSH, T-SOD, T-AOC, and TrxR were significantly decreased (allP<0.05) and the expression levels of ROS and MDA were significantly increased (allP<0.05) in a concentration-dependent manner in A549 cells treated with HPS-1, and these effects were significantly weakened in A549 cells with time extending (allP<0.05). Conclusion HPS-1 has a markedly effect on inhibiting cellular proliferation and inducing cellular apoptosis of lung adenocarcinoma A549 cells, which may be associated with the change of oxidation/antioxidant.
Objective To explore the effect of interfering RNA (shRNA) on biological activity of A549 cells and tumor growth in nude mice after knockdown of estrogen receptor α (ERα) gene. Methods The ERα gene in A549 cells was knocked down by shRNA. RT-PCR and Western blot were used to detect the gene expression and protein expression after knockdown; colony formation experiment was used to detect the proliferation of cells, and RT-PCR was used to detect the expression of Ki-67 and PCNA; flow cytometry was used to detect apoptosis rate; transwell assay was used to detect cell invasion ability; Western blot was used to detect the expression of epithelial cadherin (E-cad) and neuropathic cadherin (N-cad) protein. The control group and A549 cells transfected with ERα-shRNA1 were injected subcutaneously in nude mice to construct transplanted tumors. Immunohistochemistry was used to detect the expression of Ki-67 and N-cad in tumor tissues. Results Compared with the control group, after transfection of ERα-shRNA1 and ERα-shRNA2, the mRNA and protein expressions of ERα were reduced significantly (P<0.05), and shRNA1 with high interference efficiency was used for subsequent experiments. Compared with the control group, the A549 cells were transfected with ERα-shRNA1, the colony formation rate was down-regulated significantly (P<0.05), the apoptosis rate was increased significantly (P<0.05), the expression of Ki-67 and PCNA were down-regulated significantly (P<0.05), the number of invasive cells was reduced significantly, the expression of E-cad was increased, and the expression of N-cad was decreased (P<0.05). The results of tumor formation in nude mice showed that interfering with ERα expression can significantly inhibit tumor growth (P<0.05), and down-regulate the rate of Ki-67 and N-cad positive cells (P<0.05). Conclusion Knockdown of ERα inhibits the proliferation and migration ability of NSCLC cells and the occurrence and development of transplanted tumors in nude mice.
Objective To monitor the importance of establishing lung cancer models for immunological treatment through in vivo imaging system (IVIS). Methods In this study, a new optical bioluminescence IVIS was used to confirm the tumour formation and luminescence in male BALB/c nude mice by injecting A549-luc cells. First, A549-luc cells which expressed luciferase stably were transferred into nude mice by tail vein injection in order to establish a stable and reliable model of lung cancer. Then, D-fluorescein potassium salt was intraperitoneally injected every other week. The tumor formation and growth were dynamically observed on day 7th, 14th and 21st by IVIS Spectrum and pathological exam with hematoxylin-eosin staining. Results Animal model of lung cancer was successfully established, and the development of lung cancer was effectively monitored by IVIS real-time fluorescence value which was consistent with pathological exam, and tumor volume was correlated with fluorescence intensity (r=0.7996, P<0.01). Conclusions IVIS has multiple benefits, including high sensitivity and specificity, simple operation, and no radiation. IVIS Spectrum can measure the fluorescence of tumor formed by injection of A549-luc cells in nude mice metastasis of lung cancer in a non-invasive, real-time and dynamic mode, which is worthy of promotion for using in clinical research.