Construction of eukaryotic expression vector miRNA let-7a1 and its effect on the proliferation of lung cancer A549 cells

AIM: To construct a recombinant eukaryotic expression vector, pSilencer 4.1-let-7a1 and to express it in lung cancer A549 cells for detecting its effect on the proliferation of A549 cells. METHODS: The pre-let-7a1 sequence was amplified by RT-PCR using RNA from human lung cancer A549 cells, and then inserted into pSilencer 4.1-CMV neo vector to generate pSilencer 4.1-let-7a1 which was transfected into lung cancer A549 cells. The expression of miRNA let-7a1 was verified by RT-PCR. Its activity in A549 cells was determined by luciferase reporter assay after cotransfection of let-7a1 target sequence-reporter gene plasmid with pMIR-report let-7a1T, which was constructed by inserting let-7a1 target sequence into the luciferase reporter 3’UTR of pMIR-report luciferase vector. The effect of pSilencer 4.1-let-7a1 transfection on A549 cell proliferation was detected by MTT method. RESULTS: The sequences of cloned pre-let-7a1 were correct. RT-PCR results indicated that pSilencer 4.1-let-7a1 was effectively expressed in the transfected A549 cells. The relative luciferase activity was decreased significantly after A549 cells were co-transfected with pSilencer 4.1-let-7a1 and pMIR-report let-7a1T, indicating that let-7a1 was expressed effectively and had biologic activity in A549 cells that were transfected with pSilencer 4.1-let-7a1. MTT results showed that miRNA let-7a1 gene overexpression in A549 inhibited cell proliferation. CONCLUSION: The eukaryotic expression vector pSilencer 4.1-let-7a1 is successfully constructed and effectively expresses in A549 cell. The overexpression of miRNAlet-7a1 gene inhibits lung cancer A549 cell proliferation.     

miR-486 targeted regulation of PTEN on LPS-induced apoptosis of alveolar epithelial cell A549

AIM: To investigate the effect of microRNA-486 (miR-486) on lipopolysaccharide (LPS)-induced apoptosis of alveolar epithelial cell A549. METHODS: A549 cells were treated with LPS, and the expression of miR-486 was detected by RT-qPCR. miR-486 mimics were transfected into LPS-induced A549 cells, and RT-qPCR was used to detect the up-regulation effect. The apoptotic rate was analyzed by flow cytometry and the protein levels of cleaved caspase-3 (C-caspase-3) and C-caspase-9 were determined by Western blot. The target gene prediction software was used to predict the target gene PTEN of miR-486. Luciferase reporter vector was used to identify the target relationship. pcDNA 3.1-PTEN and miR-486 mimics were co-transfected into A549 cells to detect the effect of PTEN up-regulation on apoptosis of miR-486 mimics transfected A549 cells stimulated with LPS. RESULTS: After LPS treatment, the expression of miR-486 in A549 cells was significantly decreased (P<0.05). Transfection of miR-486 mimics significantly up-regulated the expression of miR-486 in A549 cells stimulated with LPS (P<0.05). The apoptotic rate of A549 cells and the protein levels of C-caspase-3 and C-caspase-9 were significantly increased after LPS treatment (P<0.05). Up-regulation of miR-486 significantly down-regulated LPS-induced apoptosis of A549 cells (P<0.05). The expression of PTEN was negatively regulated by miR-486. Transfection of pcDNA 3.1-PTEN significantly increased the expression of PTEN, promoted the apoptosis and increased the protein levels of C-caspase-3 and C-caspase-9 in A549 cells stimulated with LPS after co-transfection with miR-486 mimics(P<0.05). CONCLUSION: miR-486 inhibits PTEN expression and reduces LPS-induced apoptosis of A549 cells.     

Role of androgen receptor in prostate cancer cell proliferation by use of RNAi

AIM: To study the role of androgen receptor (AR) in hormone-dependent and hormone-independent prostate cancer cell proliferation by knocking down AR expression with adenovirus-delivered siRNA. METHODS: Four well-designed siRNAs were synthesized and inserted into the adenovirus plasmid pShuttle-H1-Ri. The recombinant pShuttle-H1-Ri-AR plasmid was then co-transfected with pcDNA-AR to HEK293 cell line and Western blot was used to detect the inhibitory efficiency of different siRNAs on AR expression. Recombinant adenovirus containing more efficient siRNAs were prepared and used to infect three different humane prostate cancer cell lines including LNCap、C4-2B and CWR22Rv1. The efficiency of knocking down AR expression was detected by Western blot. The effect of AR-knocking down on cell proliferation was detected by MTT colorimetric assay. RESULTS: All of the four designed siRNAs could knock down AR expression in transient co-transfection. Infecting with recombinant adenovirus containing more efficient siRNAs in hormone-dependent and hormone-independent prostate cancer cell lines specifically knocked down AR expression with high efficiency. Knocking down AR expression significantly decreased the proliferation rate in all these prostate cancer cells. CONCLUSION: The suppressed expression of AR in prostate cell lines mediated by siRNA could efficiently inhibit the cell proliferation, and these results show that AR plays an important role in the proliferation of hormone-dependent and hormone-independent prostate cancer cells. AR is an important therapeutic target for the treatment of prostate cancer.     

Inhibitory effects of nm23-H1 gene on proliferation and invasion of A549 cell line

AIM:To study the inhibitory effects of nm23-H1 gene on proliferation and invasion of human lung adenocarcinoma A549 cell line. METHODS:Recombinant eukaryotic expression vector pcDNA3.1-nm23-H1 containing full length of human nm23-H1 cDNA was constructed and transfected into a human lung adenocarcinoma A549 cell line by lipofectamine. Cell strain that expressed nm23-H1 stably was screened out by G418 and named pcDNA-nm23-A549. Expression of nm23-H1 was identified by RT-PCR and immunohistochemistry. Growth curves were drawn to detect the inhibitory effects on cell proliferation. Cell cycle of pcDNA-nm23-A549 was examined by flow cytometry. Atomic force microscopy was used to observe the filopodia on the surface of the cells. RESULTS:Introduction of nm23-H1 obviously inhibited the proliferation of A549. Expression of nm23-H1 did not induce apotosis in A549 cells but increased the percentage of phase G₁ cells and decreased phase S cells. Meanwhile, phase G₁ to phase S transition was restrained. Filopodia in the cell surface was much fewer and its structure changed in cells transformed. CONCLUSION:nm23-H1 is capable of inhibiting A549 proliferation and decreasing its metastatic ability, probably by interfering with cell cycle and cell surface structure.     

H IF-1αm ediates effect of interm ittent hypoxia on biological behavior of A 549 cells in vitro

ATM: To investigate whether hypoxia-inducible factor 1α (HIF-1α) mediates the effect of intermittent hypoxia on A549 cell viability, apoptosis and invasive ability METHODS: A549 cells were transfected with HIF-1α-siRNA and cultured under intermittent hypoxia. The expression of HIF-1α and its downstream genes, such as Bcl-2, Bax, P53, P21 and VEGF at mRNA and protein levels was determined by real-time PCR and Western blot. The viability of the A549 cells was measured by MTT assay. The apoptosis and cell cycle distribution of the A549 cells were examined by flow cytometry. The invasive ability of the A549 cells was detected by transwell test. RESULTS: The expression levels of HIF-1α, Bcl-2 and VEGF in non-HIF-1α-siRNA transfected A549 cells cultured in intermittent hypoxia environment[blank controlgroup(IH C),empty vector control group (IH E) and negative control group (IH N)] were higher than those in the A549 cells in normoxia group (RA), but the expression levels of Bax and P21 were lower than those in RA group (P<0.05). The siRNA-mediated HIF-1α gene silencing[intermittent hypoxia silenced group (IHS)] resulted in obvious down-regulation of HIF-1α, Bcl-2 and VEGF, and significant increase in the protein expression of P21 and Bax(P<0.05). The expression level of P53 in intermittent hypoxia groups was significantly higher than that in RA group, and no significant difference of P53 expression in different intermittent hypoxia groups was observed. Compared with normoxia, intermittent hypoxia resulted in significantly enhanced cell viability, decreased apoptosis, and enhanced invasive ability of non-HIF-1α-siRNA transfected A549 cells (P<0.05). The siRNA-mediated HIF-1α gene silencing resulted in significant cell viability inhibition, elevated apoptotic rate and decreased invasive ability under hypoxic condition (P<0.05).CONCLUSION: Intermittent hypoxia promotes the viability and invasion of A549 cells by HIF-1α-mediated downstream gene expression. HIF-1α gene silencing inhibits A549 cell growth and invasion under intermittent hypoxia by inhibition of HIF-1α signal pathways in vitro.     

Effect of antisense RNA targeting Polo-like kinase 1 on cell growth in A549 lung cancer cells

AIM: To investigate the effect of Polo-like kinase-1 (Plk1) depletion on cell cycle progression and cell growth in lung cancer cells.METHODS: A recombinant plasmid containing antisense RNA targeting Plk1 (pcDNA3-Plk1) was transfected into A549 cells by lipofectine. RT-PCR and Western blotting were used to examine Plk1 gene expression. Cell proliferation was evaluated by cell counting and BrdU labeling. Cell cycle distribution and apoptosis were examined by flow cytometry. Inhibition rate (IR) of vinorebline (NVB) was determined by MTT assay. RESULTS: After transfected with pcDNA3-Plk1 into A549 cells, the expression levels of Plk1 mRNA and protein were greatly decreased. Abnormal morphological changes of cells and growth inhibition were observed in pcDNA3-Plk1 transfected cells. The BrdU labeling index was significantly lower than that in control group (P<0.05). Cells showed a strong G₂/M arrest and apoptosis 72 h post transfection. IR of vinorebline in pcDNA3-Plk1 transfected groups was significantly higher than that in other groups. CONCLUSION: Antisense RNA targeting Plk1 is capable of suppressing Plk1 expression, and therefore, significantly inhibits cellular proliferation, induces cell cycle arrest and apoptosis. Moreover, the sensitivity of lung cancer cells to chemotherapy is increased.     

Cepharanthine promotes A549 cell apoptosis by regulating miR-150 and miR-182

AIM: To investigate the effect of cepharanthine on the growth of human lung carcinoma A549 cells and the underlying mechanism. METHODS: After A549 cells were treated with cepharanthine, the growth inhibitory rate was detected by MTT assay. The cell morphological changes were observed under light microscope. The apoptosis of the A549 cells was analyzed by flow cytometry. The expression of microRNA (miR)-150, miR-182, p53 mRNA and FOXO1 mRNA were detected by real-time PCR. The downstream target genes were predicted by software, and the expression of p53 and FOXO1 was determined by Western blot. RESULTS: After cepharanthine treatment, the growth of A549 cells was inhibited, the apoptosis rate was significantly increased, and the expression levels of miR-150 and miR-182 were significantly decreased. With cepharanthine treatment at 10 μmol/L, the expression levels of p53 and FOXO1 were elevated; however, with cepharanthine at 30 μmol/L, the expression levels of p53 and FOXO1 were decreased. After transfection with miR-150, the expression of p53 was significantly decreased, while the expression of FOXO1 was significantly decreased after transfection with miR-182. CONCLUSION: Cepharanthine inhibits the growth of A549 cells and promotes the apoptosis of A549 cells by inhibiting the expression of miR-150 and miR-182. miR-150 and miR-182 may down-regulate the expression of p53 and FOXO1, respectively.     

Expression of miRNA-181a in human lung adenocarcinoma cells and its effect on cell function

AIM: To study the expression of microRNA (miRNA)-181a in different human lung adenocarcinoma cell lines, and to investigate the effect of miRNA-181a on cell function and its mechanism in human lung adenocarcinoma drug resistant cell A549/DDP. METHODS: Real-time PCR was used to detect the expression of miRNA-181a in BEAS-2B cells, A549 cells and A549/DDP cells. The A549/DDP cells were transfected with pGenesil-miRNA-181a eukaryotic expression plasmid. At the same time, the untransfection group and negative transfection group were also set up. The expression of miRNA-181a, cell viability, cell growth inhibition and apoptosis rate during cis-diamminedichloroplatinum (DDP) treatment, cell cycle, cell invasion, the protein expression of miRNA-181a target genes bcl-2 and p53 in the A549/DDP cells were determined by real-time fluorescence quantitative PCR, MTT assay, flow cytometry, Transwell method and Western blot, respectivly. RESULTS: The expression of miRNA-181a in A549 cells and A549/DDP cells was significantly lower than that in BEAS-2B cells, and the lowest expression level was observed in A549/DDP cells (P<0.05). The expression of miRNA-181a in A549/DDP cells was significantly increased after transfection with pGenesil-miRNA-181a (P<0.05). The cell viability, cell cycle and invasion ability of the A549/DDP cells were inhibited after miRNA-181a transfection (P<0.05). The cell growth inhibition rate and apoptotic rate of the A549/DDP cells were increased (P<0.05). The expression of Bcl-2 was reduced, but the expression of P53 was increased after transfection with miRNA-181a in A549/DDP cells (P<0.05). CONCLUSION: miRNA-181a may be correlated with the development of human lung adenocarcinoma. miRNA-181a can serve as a new target for treatment of lung cancer.     

Effect of siRNA for survivin gene on growth and apoptosis in A549 cells

AIM:To observe the influence of lentiviral vectors expressing siRNA for survivin gene knockdown in A549 cells, sequentially as tools to explore the molecule pathogenesis and new gene therapy of lung adenocarcinoma. METHODS:The lentiviral vectors, which express survivin siRNA, were constructed and transfected into A549 cell strain. The titers of the lentiviruses were determined by 293T cells. The expressions of survivin and caspase-3 were detected by Western blotting and RT-PCR. The cell cycle and cell growth of A549 cells were examined by MTT and FCM．RESULTS:The expression of survivin was suppressed effectively by siRNA targeting survivin. The expression of survivin mRNA decreased by 97%. The expression of survivin protein decreased by 94%. The rate of cell growth was decreased. The G1 phase cells were increased, whereas S phase cells were decreased. CONCLUSION:The lentivirus vectors expressing siRNA for survivin can significantly inhibit gene expression and the cell growth, and markedly induce the apoptosis. It is hopeful to be a new gene therapy of lung adenocarcinoma.     

Salinomycin promotes the apoptosis-inducing effect of gefitinib on human lung adenocarcinoma cell line A549

AIM: To investigate the effect of salinomycin alone or in combination with gefitinib (an inhibitor of epidermal growth factor receptor tyrosine kinase) on the growth and apoptosis of human non-small-cell lung cancer cell line A549. METHODS: The inhibitory effect of salinomycin on the growth of A549 cells was tested by MTT assay. The cell apoptosis and the level of mitochondrial membrane potential were determined by flow cytometry. The activity of caspase-3, -8, and -9 was measured by the method of colorimetry. The protein levels of cytochrome C, Bcl- 2, p-EGFR, p-Akt and p-ERK were detected by Western blotting. RESULTS: Salinomycin or gefitinib alone inhibited the growth of A549 cells in a dose-dependent manner. Salinomycin or gefitinib also induced apoptosis of the cells. Salinomycin combined with gefitinib produced stronger inhibitory effect on the cell proliferation, and a significant increase in cell apoptosis was also observed. Compared with control group, salinomycin alone significantly reduced mitochondrial membrane potential, transitorily increased the levels of intracellular reactive oxygen species (ROS), cytoplasmic cytochrome C and Ca2+, and increased the activity of caspase-3, -8 and -9 in A549 cells. Gefitinib alone inhibited the protein expression of p-EGFR, p-Akt and p-ERK, but no obvious effect on the release of cytochrome C and the activity of caspase-3, -8 and -9 was found. The combination of salinomycin and gefitinib significantly reduced the protein levels of Bcl-2, p-EGFR, p-Akt and p-ERK, but the protein levels of EGFR, Akt and ERK were not obviously changed. CONCLUSION: The synergy of salinomycin and gefitinib is observed. Salinomycin inhibits the growth and induces apoptosis of human lung carcinoma A549 cells through Bcl-2 pathway and mitochondrial apoptosis pathway. Salinomycin also increases the sensitivity of A549 cells to gefitinib.     

Effect of PDK1 on biological characteristics of lung cancer A549 cells

AIM: To investigate the effects of 3-phosphoinositide-dependent protein-1 (PDK1) on the biological characteristics of non-small-cell lung cancer cell line A549 and the underlying mechanisms.METHODS: The expression levels of PDK1 in lung normal epithelial cell line BEAS-2B and different lung cancer cell lines H460, SPCA1 and A549 were determined by Western blot and real-time PCR. Small interfering RNA was used to down-regulated PDK1 expression in the A549 cells, and then cell viability and apoptosis were measured by CCK-8 assay and flow cytometry, respectively. The expression of cell cycle-and apoptosis-related molecules at protein level and the activation of Akt/FoxO1 pathway were measured by Western blot. Insulin-like growth factor-1 (IGF-1, one of the most potent Akt activators) was used to evaluate the interaction between PDK1 and Akt/FoxO1 pathway.RESULTS: Compared with lung normal epithelial cell line BEAS-2B, PDK1 expression in the lung cancer cell lines was obviously increased (P<0.05). Knockdown of PDK1 suppressed cell viability and cell cycle, but promoted the apoptosis of the A549 cells. The results of Western blot showed that the protein levels of cyclin D1, CDK4, p-Rb, Bcl-2, p-Akt and cytoplasmic p-FoxO1 were significantly decreased after knockdown of PDK1, with increases in the protein levels of P27, cleaved caspase-3 and nuclear FoxO1. Pre-incubation with IGF-1 partly reversed the effect of PDK1 knockdown on Akt/FoxO1 pathway and increased the viability of A549 cells.CONCLUSION: In human non-small-cell lung cancer A549 cells, knockdown of PDK1 suppresses cell viability and promotes cell apoptosis by regulating the expression of cell cycle-and apoptosis-related molecules via Akt/FoxO1 pathway, suggesting that PDK1 may be a potential target for diagnosis and theatment of lung cancer.     

Celastrol blocks cell cycle of A549 cells by regulating miR-17-5p/miR-155-5p and targeting cyclin D1

AIM: To investigate the effect of celastrol on the cell cycle of human lung adenocarcinoma A549 cells and to probe into its mechanisms.METHODS: A549 cells were exposed to celastrol at gradient concentrations. The cell viability and apoptosis were detected by MTT assay and flow cytometry, respectively, and the median lethal concentration (LC₅₀) of celastrol was screened. The A549 cells were treated with celastrol at LC₅₀, and the cell cycle was detected by flow cytometry. The expression of cyclin D1 was determined by Western blot, and the expression of microRNA (miR)-17-5p and miR-155-5p was detected by real-time PCR. The correlation between cyclin D1 and miR-17-5p or miR-155-5p was predicted by bioinformatics software. After miR-17-5p mimics/miR-155-5p mimics/mutant-miR-17-5p/mutant-miR-155-5p and pcDNA-GFP-cyclin D1-3'UTR were cotransfected into the A549 cells, the changes of GFP expression were evaluated by fluorescence microscopy and flow cytometry. Finally, after miR-17-5p mimics or miR-155-5p mimics were transfeced into the A549 cells, the expression of miR-17-5p and miR-155-5p was detected by real-time PCR, and the protein level of cyclin D1 was determined by Western blot. RESULTS: With the increasing concentration of celastrol, the viability inhibition rate and apoptotic rate of the A549 cells were increased, indicating that celastrol effectively inhibited the growth of A549 cells and induced apoptosis. The LC₅₀ of celastrol was almost 3 μmol/L. After treatment with celastrol at LC₅₀, the A549 cell cycle was arrested at G₁ phase, the protein expression of cyclin D1 was down-regulated (P<0.01), and the expression levels of miR-17-5p and miR-155-5p were significantly increased (P<0.01). The results of bioinformatics software prediction indicated that there were binding sites for miR-17-5p and miR-155-5p in the 3'-UTR of cyclin D1. After cotransfected with miR-17-5p or miR-155-5p and pcDNA-GFP-cyclin D1-3'UTR into the A549 cells, the expression of GFP declined (P<0.05). After miR-17-5p or miR-155-5p mimics were transfected into A549 cells, the results of real-time PCR showed this treatment significantly increased the miRNA expression (P<0.01), and the results of Western blot showed the transfection inhibited cyclin D1 expression (P<0.01).CONCLUSION: Celastrol blocks the A549 cells at G₁ phase, inhibits the viability and induces apoptosis, which may be caused by up-regulating the expression of miR-17-5p and miR-155-5p, and then down-regulating cyclin D1 expression. This study provides a new theoretical basis for the treatment of non-small-cell lung cancer with celastrol.     

Construction of siArid2 recombinant adenovirus and its effect on proliferation of hepatocarcinoma cells

AIM: To observe the effects of Arid2gene on cell proliferation and cell cycle by interference of endogenous Arid2 expression in hepatoma cells. METHODS: Three pairs of shRNA targeting Arid2gene were cloned into a shuttle vector to construct recombinant adenovirus plasmids. HEK293 cells were transfected with the recombinant adenovirus plasmids. After several rounds of the package and amplification, the high-titer adenoviruses AdsiArid2-1~3 were obtained. To verify the inhibitory effects of AdsiArid2 adenoviruses, Western blotting was used to detect the endogenous Arid2 protien expression in SMMC-7721 cells. Cell growth and cell cycle analysis were carried out by MTS assay and flow cytometry. RESULTS: High- titer recombinant adenovirus of siArid2 were successfully obtained, and named AdsiArid2-1~3, among which the AdsiArid2-3 had the best inhibitory effects. MTS assay showed that the absorbance values at 490 nm were increased at 72 h and 96 h after transduction compared with the mock and Adsicontrol groups. These data indicated that knockdown of Arid2 promoted the proliferation rate of SMMC-7721 cells(P<0.05). Moreover, the flow cytometry analysis revealed that the G1-phase distribution at 72 h in AdsiArid2 group was lower than that in mock group and Adsicontrol group. In contrast, the S-phase distribution in AdsiArid2 group was much higher than that in mock group and Adsicontrol group. CONCLUSION: The recombinant plasmids and recombinant adenovirus were successfully constructed. shRNA-mediated knockdown of Arid2 promotes the proliferation and the transition from G1 phase to S phase of hepatoma cells.     

Radiosensitizing effect of 2-methoxyestradiol on NSCLC cell lines by blocking cell cycle

AIM: To investigate the efficiency of 2-methoxyestradiol (2-ME) as radiosensitizing agent for the treatment of lung cancer cells. METHODS: Cell line A549 and GLC-82 originated from human non-small cell lung cancer were cultured in vitro. Study group (2-ME in different concentrations) and control group without 2-ME were set up. Cell proliferation was measured by MTT assay that lung cancer cells were treated with 2-ME for 24 h, then the cells were exposed from 0 to 8Gy radiation, and the survival fraction was determined by clone forming test. Flow cytometry was used to measure the effects of 2-ME on cell cycle distribution. RESULTS: MTT assay showed minimum effective concentration value was 0.15625×10-6 mol/L in GLC-82 and 1.25×10-6 mol/L in A549 cells. Compared to control group, exposed GLC-82 cells or A549 cells to minimum effective concentration of 2-ME for 24 h before irradiation resulted in an enhancement of radiation. The protection enhancement factor was 1.98 and 2.06 in GLC-82 and A549 cells, respectively. Flow cytometry analysis of cell cycle progression demonstrated G2/M phase arrest in both cells in a dose dependent manner. No obvious change of CDK2 activity in both GLC-82 cells and A549 cells was observed. CONCLUSION: 2-ME enhances radiosensitivity by G2/M phase arrest in the cell cycle.     

Antisense nucleic acid of K-ras inhibits growth of lung adenocarcinoma cancer cell A549

AIM: To explore the mechanism of inhibiting lung adenocarcinoma cancer mediated by antisense nucleic acid of K-ras.METHODS: The expression of K-ras was detected in A549 cells and 6 lung adenocarinoma samples. The antisense expression vector of K-ras was successfully constucted (named antisense- K-ras-pcDNA3.1). After transfection, the growth curve and Apoptosis were determined by MTT assay and Annexin V staining, respectively. Cyclin A, cyclin D1, cyclin E, CDK2, CDK4, P53, Rb and caspase-3 were detected by Western blotting. RESULTS: K-ras was highly expressed in 4 samples of lung adenocarcinoma and A549 cells. In A549 cells transfected with antisense nucleic acid of K-ras, the cell growth was significantly inhibited and the apoptosis was visible.The expression levels of cyclin A, cyclin D1, cyclin E, CDK2 and CDK4 were significantly decreased, and the expression levels of P53, Rb and caspase-3 were significantly increased. CONCLUSION: The growth inhibition in A549 cells mediated by antisense nucleic acid of K-ras is related to the decreases in the expression of cyclin A, cyclin D1, cyclin E, CDK2 and CKD4 , and the increases in the expression of P53, Rb and caspase-3.     

Salinomycin inhibited proliferation and induced apoptosis of cisplatin-resistant human lung adenocarcinoma cell line A549/DDP

AIM: To investigate the effect of salinomycin on the proliferation and apoptosis of cisplatin-resistant human lung adenocarcinoma cell line A549/DDP. METHODS: The inhibitory effect of salinomycin on the growth of A549/DDP cells was tested by MTT method in vitro . The apoptosis and mitochondrial membrane potential (ΔΨ_m) of A549/DDP cells were assayed by flow cytometry. The activity of caspase-3, 8 and 9 was determined by the method of colorimetry. The levels of cytochrome C, Bcl- 2, Bax, β-catenin, and phosphorylated low-density lipoprotein receptor-related protein 6(p-LRP6) were measured by Western blotting. RESULTS: Salinomycin inhibited the growth of A549/DDP cells in a dose-dependent manner. Salinomycin at concentration of 0.2 μmol/L decreased ΔΨ_m level, and increased reactive oxygen species (ROS), cytochrome C and cytosolic Ca²⁺ release in the cells. Salinomycin also increased the acti-vity of caspase-3, 8, and 9 in the cells, reduced the ratio of Bcl-2/Bax, and decreased the levels of β-catenin and p-LRP6. CONCLUSION: Salinomycin depresses the cell growth by inhibiting Wnt signaling, and induces the apoptosis of cisplatin-resistant human lung adenocarcinoma cell line A549/DDP via mitochondria-dependent and Bcl-2/Bax pathways.     

Roles of maspin in biological behaviors of A549 cells

AIM: To investigate the roles of maspin in the biological behaviors of non-small-cell lung cancer A549 cells.METHODS: Full-length coding region of maspin was amplified by PCR from human normal breast tissue and cloned into MSCV vector. Virus supernatants was produced by Phoenix A packaging system, and target cell line was infected with the virus supernatants. The transfected cells were screened with puromycin. The cell line with maspin over-expression was identified by real-time PCR and Western blot. Cell growth, migration and invasion were investigated by xCelligence system.RESULTS: Maspin over-expression vector was successfully constructed. The cell line with maspin over-expression was established. No difference of the growth between A549-control cells and A549-maspin cells was observed. The migration and invasion were quite different between A549-control cells and A549-maspin cells. The expression level of integrin β1 in A549-maspin cells was decreased compared with A549-control cells.CONCLUSION: Maspin has no effect on the growth of A549 cells. Maspin suppresses the migration and invasion of A549 cells, in which integrin β1 is involved.