Let-7a-3p inhibits activity of cancer stem cells in human lung cancer A549 cells by targeting IGF1R

AIM:To study the effect of let-7a-3p on the activity of cancer stem cells in human lung cancer A549 cells and its molecular biological mechanism. METHODS:The exepression levels of let-7a-3p in lung cancer cell lines A549, NCI-H1299, SPC-A1, H1650 and HCC-827, and human normal bronchial epithilial cell line BEAS-2B were compared by RT-qPCR. The lung cancer A549 cells were transfected with let-7a-3p mimic and negative control mimic, as let-7a-3p group and negative control group, respectively, and non-transfected control group was also set up. The content of let-7a-3p in each group was detected by RT-qPCR. Tumor sphere formation assay was used to detect the tumor sphere formation ability in 3 groups of the cancer stem cells. The proportion of cancer stem cells was detected by flow cytometry. The protein levels of NANOG, OCT4 and insulin-like growth factor 1 receptor (IGF1R) were determined by Western blot. The target gene of let-7a-3p was predicted by the bioinformatic method. The relationship between let-7a-3p and IGF1R was analyzed by double luciferase assay. Western blot was used to detect whether IGF1R over-expression antagonized the inhibitory effect of let-7a-3p on the activity of cancer stem cells. A subcutaneous transplantation tumor model was also established and the effect of let-7a-3p in vivo was observed. RESULTS:The expression level of let-7a-3p in the lung cancer cell lines was significantly lower than that in the normal bronchial epithelial cell line (P<0.01). The expression level of let-7a-3p in the A549 cells of let-7a-3p group was significantly up-regulated compared with non-transfected group (P<0.01). The number of tumor spheres in let-7a-3p group was significantly lower than that in non-transfected group. The percentage of CD133⁺ cells in let-7a-3p group was significantly lower than that in non-transfected group (P<0.01). The protein expression of NANOG and OCT4 in let-7a-3p group was significantly lower than that in non-transfected group (P<0.01). Bioinformatic prediction showed that let-7a-3p complementarily matched the 3'-UTR of IGF1R, and IGF1R might be the target gene of let-7a-3p. Luciferase assay confirmed that IGF1R was the direct downstream target gene of let-7a-3p. The protein expression of IGF1R in let-7a-3p group was significantly decreased (P<0.01). Subcutaneously transplantated tumor in let-7a-3p group was significantly smaller than that in non-transfected group. CONCLUSION:Let-7a-3p may affect the expression of lung cancer stem cell-related proteins and inhibit the potential of lung cancer stem cells by down-regulating its downstream target gene IGF1R.     

β-estradiol promotes invasion and migration of lung cancer A549 cells via ERβ-mediated ERK1/2 membrane-initiated steroid signaling

AIM: To investigate the regulatory mechanism of β-estradiol in the invasion and migration of lung cancer A549 cells. METHODS: Breast cancer MCF-7 cells and lung cancer A549 cells were cultured in vitro. The MCF-7 cells were used as the estrogen receptor (ER) positive expression cell model. Real-time PCR and immunofluorescence were employed to measure the expression level and the localization of ER in A549 cells. The phosphorylation of ERK1/2 upon β-estradiol stimulation was quantified by Western blot. The invasion and migration abilities of A549 cells upon β-estradiol stimulation with or without ERK1/2 inhibitor PD98059 were measured by Transwell and Cell-IQ assays. RESULTS: ERβ was the dominant ER subtype in the A549 cells and primarily comprised of ERβ2 and ERβ5. Immunofluorescence revealed that ERβ expression was mainly localized in the cytoplasm. β-estradiol induced phosphorylation of ERK1/2 and promoted the invasion and migration of the cells. Inhibition of ERK1/2 signaling reversed β-estradiol-promoted invasion and migration of A549 cells. CONCLUSION: ERβ-mediated membrane-initiated steroid signaling is involved in the process of β-estradiol-promoted invasion and migration of A549 cells, through which ERK1/2 signaling plays a pivotal role.     

Anticancer function of Shp2 in lung adenocarcinoma A549 cells and rela-ted molecular mechanisms

AIM: To explore the anticancer function of Shp2 in lung adenocarcinoma A549 cells and the related molecular mechanisms. METHODS: The viability and proliferation of A549 cells treated with Shp2 specific inhibitor Phps-1 or cisplatin (DDP) were measured by CCK-8 assay and EdU assay. Annexin V-FITC/PI double staining was applied to detect apoptotic rate of A549 cells with different interventions. The protein levels of caspase-3-17p, Bcl-2, Bax, p-STAT3/STAT3 and p-ERK/ERK were determined by Western blot. RESULTS: Compared with control group, Phps-1 at the concentration of 20 μmol/L significantly increased the viability of A549 cells after 24 h of treatment (P<0.05). Meanwhile, the proliferation rate of A549 cells in Phps-1 20 μmol/L group was significant increased compared with control group (P<0.05). The apoptotic rate of A549 cells in DDP treatment group decreased from 13.01%±2.62% to 3.67%±0.93% after adding Phps-1 (P<0.05). Phps-1 down-regulated the protein levels of caspase-3-17p, Bax and p-ERK, but up-regulated p-STAT3.CONCLUSION: Shp2 is a tumor suppressor in A549 cells, which may be associated with the activation of STAT3 signal pathway.     

Study on expression of long non-coding RNA in colon cancer tissues and adjacent tissues

AIM: To screen the differentially expressed long non-coding RNA (lncRNA) in colon cancer, and to explore its expression in colon cancer tissues and adjacent tissues. METHODS: The "Colon adenocarcinoma:Person neoplasm cancer status" which consisted of 36 cases of colon cancer tissues and 29 cases of normal colonic tissues was downloaded from the lncRNAtor database. The candidate genes were selected from these differentially expressed lncRNAs based on artificial criterion (P<0.01; fold change ≥ 2 or<0.5) and then validated by real-time PCR in 60 pairs of colon cancer tissues and adjacent tissues. RESULTS: A total of 50 lncRNAs were differentially expressed in colon cancer tissues, including 28 up-regulated and 22 down-regulated (P<0.01). The verifying results displayed that HNF1A-AS1 and ZDHHC8P1 were up-regulated (P<0.01), and SUZ12P expression was down-regulated (P<0.05), but the expression of AC069513.3 was not statistically significant between colon cancer tissues and adjacent tissues. The abilities of HNF1A-AS1, ZDHHC8P1, SUZ12P and AC069513.3 to discriminate the colon cancer from normal adjacent tissue by the ROC curve with an AUC of 0.729 (sensitivity 78%, specificity 67%), 0.617 (sensitivity 68%, specificity 55%), 0.689 (sensitivity 66%, specificity 55%) and 0.518 (sensitivity 52%, specificity 48%) were observed. CONCLUSION: Long non-coding RNA HNF1A-AS1 and ZDHHC8P1 are up-regulated and SUZ12P is down-regulated in colon cancer tissues, suggesting that they may be involved in the pathogenesis of colon cancer.     

CASC2/miR-18a/BTG3 signaling inhibits cell migration and invasion of non-small cell lung cancer

AIM: To explore the function and molecular mechanism of long non-coding RNA CASC2 in non-small-cell lung cancer (NSCLC) cell migration and invasion. METHODS: RT-qPCR and Western blot were used to detect the expression of CASC2, microRNA-18a (miR-18a) and BTG3 in human bronchial epithelial cell line 16-HBE, and NSCLC cell lines A549 and H1299. The interaction between CASC2 and miR-18a or miR-18a and BTG3 was predicted by bioinformatics software and verified by double-luciferase reporter assays. Transwell assays were performed to detect the migration and invasion abilities of the NSCLC cells. RT-qPCR and Western blot were used to determine the regulatory effects of CASC2 on miR-18a and BTG3 expression. RESULTS: Compared with 16-HBE cells, the expression of CASC2 and BTG3 was significantly down-regulated in the NASCL cells, while miR-18a was significantly over-expressed (P<0.05). CASC2 acted as a molecular sponge for miR-18a, and BTG3 was verified to be a target gene of miR-18a. Up-regulation of CASC2 inhibited the migration and invasion abilities of NSCLC cells, while exogenous restoration of miR-18a stimulated cell migration and invasion abilities. In addition, exogenously over-expressed miR-181a reversed the promoting effect of CASC2 on BTG3 protein expression. CONCLUSION: CASC2 promotes BTG3 expression by negatively regulating miR-18a, and then inhibits the migration and invasion abilities of NSCLC cells.     

MicroRNA-330 inhibits growth and migration of gastric cancer cells by directly targeting EGR-2

AIM:To explore the function and significance of microRNA-330 (miR-330) in the development of gastric cancer. METHODS:Forty-eight cases of gastric cancer tissues and paired adjacent tissues were collected in Department of Oncology, Affiliated Hospital of Gansu University of Chinese Medicine, and the expression levels of miR-330 were detected by RT-qPCR. The expression levels of miR-330 in the gastric cancer cells and human gastric epithelial GES-1 cells were evaluated by RT-qPCR. The viability, colony formation and migration of gastric cancer cells after transfected with miR-330 inhibitor or miR-330 mimic were analyzed by CCK-8 assay, colony formation assay and Transwell assay, respectively. Furthermore, miR-330 target gene was predicted by miRanda target gene prediction database. RESULTS:miR-330 expression was down-regulated both in gastric cancer tissues and gastric cancer cells (P<0.05). The expression levels of miR-330 were negatively associated with the tumor size, lymph metastasis, pathological grade stage and T stage (P<0.05). The viability, colony formation and migration of gastric cancer cells were significantly increased after transfected with miR-330 inhibitor (P<0.05). However, the viability, colony formation and migration of gastric cancer cells were significantly decreased after transfected with miR-330 mimic (P<0.05). Furthermore, EGR-2 was the direct target gene of miR-330. CONCLUSION:miR-330 suppresses gastric cancer cell growth and migration, and the mechanism may be related to its direct target gene EGR-2, suggesting that miR-330 may be used as a potential new target for diagnosis and targeted therapy for gastric cancer.     

Protein expression of EMMPRIN,MMP-2 and P53 detected by technique of quantum dots immunofluorescence in human lung cancer

AIM: To investigate the expression of extracellular matrix metalloproteinase inducer (EMMPRIN/CD147), matrix metalloproteinase2 (MMP-2) and P53 proteins in human lung cancer tissues and to explore the relationship between EMMPRIN protein and malignant biological behaviour of lung cancer.METHODS: Fluorescent semiconductor nanocrystals were applied, which were nanometer-sized light-emitting particles and were emerging as a new class of fluorescent probes for cancer detection due to the unique optical and electronic properties. The technique of QDs immunofluorescence histochemistry (QDs-IHC) was used to detect the protein expression of EMMPRIN, P53 and MMP-2 in the human lung cancer microarray, and co-expression of EMMPRIN/P53 proteins was also simultaneously detected by double-labeling immunofluorescence.RESULTS: Compared with non-cancerous lung tissues, the positive rates of EMMPRIN, P53 and MMP-2 proteins in the lung cancer tissues were 70.00%, 77.14% and 72.86%, respectively, and the differences were all significant (P<0.05). The positive rates of EMMPRIN, P53 and MMP-2 proteins were all significantly related with tumor staging(TNM stage) and lymph node metastasis (P<0.05). The positive correlation between EMMPRIN expression and protein levels of MMP-2 and P53 was observed (P<0.01).CONCLUSION: The protein expression of EMMPRIN, P53 and MMP-2 is correlated with the development of lung cancer. Malignant progression of lung cancer promoted by EMMPRIN may be closely related with the expression of MMP-2 and P53.     

miRNA-101-3p inhibits proliferation and migration of gastric cancer cells by targeting EZH2

AIM: To investigate the role of microRNA-101-3p (miRNA-101-3p) on the proliferation, apoptosis and invasion of gastric cancer cells and the possible regulatory mechanisms. METHODS: The expression of miRNA-101-3p in two kinds of gastric cancer cells and a gastric mucosal cell line was detected by real-time PCR. The miRNA-101-3p was overexpressed by Lipofectamine 2000 transfection with miRNA-101-3p mimics. The effects of miRNA-101-3p on cell cycle distribution and apoptosis were analyzed by flow cytometry. The effects of miRNA-101-3p on cell proliferation and migration abilities were detected by CCK-8 assay, trypan blue exclusion test and Transwell assay. The protein expression of enhancer of zeste homolog 2 (EZH2) was determined by Western blot. RESULTS: The expression of miRNA-101-3p in gastric cancer cells was lower than that in gastric mucosal cells (P<0.05). The gastric cancer cell MGC-803 had the lowest expression level of miRNA-101-3p. The result of flow cytometry showed that the population of S phase was reduced, and the population of G₀/G₁ phase and the early stage apoptotic rate were increased after the expression of miRNA-101-3p was overexpressed (P<0.05). The results of CCK-8 assay, trypan blue exclusion test and Transwell assay showed that overexpression of miRNA-101-3p significantly reduced the proliferation and migration abilities of gastric cancer cells (P<0.05). Overexpression of miRNA-101-3p decreased the protein level of EZH2 (P<0.05). CONCLUSION: miRNA-101-3p may suppresses the gastric cancer cell proliferation and migration, and promotes the gastric cancer cell apotosis by down-regulation of EZH2.     

Signal peptide sequence of human interleukin-2 influenced hEndostatin gene expression and protein secretion in HepG2 cells

AIM:The role of human interleukin-2(IL-2) signal peptide sequence in the effect of human Endostatin (hEndostatin) expression and secretion was investigated in HeG2 cells.METHODS:RT-PCR and Western-blotting were conduct to observe mRNA level difference of hEndostatin gene, its protein expression and secretion level difference between with hIL-2 signal peptide sequence and without it.RESULTS:mRNA level of hEndostatin gene in HepG2 (pBlast-hIL2-hEndo) cells was higher than that in HepG2(pBlast-hEndo)(P＜0.05). hEndostatin protein was detected only in HepG2 (pBlast-hIL2-hEndo) cells and its medium, and not in other HepG2 cells and medium.CONCLUSION:Human interleukin-2(IL-2) signal peptide sequence facilitate to increase mRNA level of hEndostatin gene, its protein expression and secretion in HepG2 cells.     

Curcumin inhibits migration and invasion of lung cancer PC-9 cells via down-regulation of nectin-4 expression

AIM: To investigate the effects of curcumin on the abilities of migration and invasion in the lung cancer PC-9 cells, and to observe the relationship between curcumin and nectin-4 expression.METHODS: The viability, migration and invasion of lung cancer PC-9 cells treated with curcumin or transfected with siNectin-4 were measured by MTT assay, wound healing test and Transwell assay, respectively. The protein levels of nectin-4, p-AKT and AKT in the PC-9 cells treated with curcumin or transfected with siNectin-4 were detected by Western blot.RESULTS: Curcumin inhibited the viability of PC-9 cells. The wound healing rates and the numbers of the transmembrane cells in curcumin 10 μmol/L and 20 μmol/L groups were decreased compared with control group without curcumin treatment. The expression level of nectin-4 was reduced after curcumin treatment for 24 h. The viability of the PC-9 cells was significantly inhibited after transfected with siNectin-4 for 48 h or 72 h (P<0.01), and the wound healing rates was decreased in siNectin-4 group compared with NC group (P<0.01). The numbers of the transmembrane cells in siNectin-4 group was significantly reduced (P<0.01). Curcumin and knockdown of nectin-4 suppressed the activation of AKT pathway in PC-9 cells. In siNectin-4+curcumin group, the cell viability reduced compared with curcumin group, and wound healing rates, cell invasive ability and AKT phosphorylation levels were decreased.CONCLUSION: Curcumin inhibits migration and invasion of the lung cancer PC-9 cells via down-regulation of nectin-4 expression and inhibition of AKT pathway.     

Effect of HMGB2 on cell cycle and proliferation of lung adenocarcinoma

AIM: To investigate the effect of high-mobility group protein B2 (HMGB2) on cell cycle and proliferation of lung adenocarcinoma cells. METHODS: Cancer RNA-Seq Nexus (CRN) was used to analyze HMGB2 expression in lung adenocarcinoma tissues. OncoLnc was used to analyze the correlation between HMGB2 and prognosis of lung adenocarcinoma patients. Cancer Single-cell State Atlas (CancerSEA) was used to analyze the correlation between HMGB2 and 14 kinds of functional states of lung adenocarcinoma. siRNA was used to inhibit HMGB2 expression in human lung adenocarcinoma A549 cells. The silencing effects were verified by real-time PCR and Western blot, and the cell proliferation was detected by CCK8 and EdU assays. RESULTS: HMGB2 was over-expressed in the lung adenocarcinoma tissues. The overall survival of the patients with lung adenocarcinoma in HMGB2 high expression group was significantly lower than that of the patients with low expression of HMGB2 (log-rank test P=0.017 3). HMGB2 expression was positively correlated with cell cycle and proliferation of lung adenocarcinoma cells. The viability and proliferation ability of A549 cells after HMGB2 expression knock-down were significantly reduced (P < 0.05). CONCLUSION: The expression of HMGB2 is positively correlated with the cell cycle and proliferation of lung adenocarcinoma, and it can be used as a potential marker for evaluating the prognosis and therapeutic target of patients with lung adenocarcinoma.     

NFATc1 promotes vascular generation of epithelial ovarian cancer transplanted tumor by regulating CXCR2, FGF-2 and PDGF-BB

AIM: To investigate the role of NFATc1 in vascular generation in the nude mice transplanted with human ovarian cancer SKOV3 cells. METHODS: NFATc1 expression was silenced by siRNA in SKOV3 cells. Human ovarian cancer transplantation nude mouse model was established by transplanting with SKOV3 cells in which the NFATc1 gene was silenced by siRNA technique. The expression of NFATc1, CXCR2, FGF-2 and PDGF-BB at mRNA and protein levels was determined by RT-PCR, Western blotting and immunohistochemical staining. The tumor growth, angiogenesis and lymphangiogenesis were also observed. RESULTS: Over-expression of NFATc1 was observed in human ovarian cancer tissues. The silencing of NFATc1 expression by siRNA decreased tumorigenesis of transplanted ovarian cancer cells in the nude mice, reduced tumor vascular generation and inhibited the expression of CXCR2, FGF-2 and PDGF-BB at mRNA and protein levels. CONCLUSION: NFATc1 is overexpressed in ovarian cancer. NFATc1 silencing regulates the tumor vascular generation. NFATc1 thus has potential as a therapeutic target and for use in the diagnosis and evaluating prognosis of epithelial ovarian cancer.     

Mechanism of microRNA-138-5p inhibiting proliferation,migration and invasion of lung cancer cells

AIM: To investigate the mechanism of microRNA-138-5p (miR-138-5p) inhibiting the proliferation, migration and invasion abilities of lung cancer cells.METHODS: The lung cancer A549 and H460 cells were transfected with miR-NC (control group) or miR-138-5p (experimental group). The bioinformatic analysis was performed to predict the target genes of miR-138-5p.The expression levels of miR-138-5p, forkhead box protein C1 (FOXC1) mRNA and vimentin mRNA were detected by RT-qPCR. The protein expression of FOXC1, vimentin, E-cadherin, N-cadherin and β-catenin was determined by Western blot. MTS method and colony formation assay were used to detect cell viability and proliferation ability. Wound healing assay and Transwell assay were used to detect cell migration and invasion ability.RESULTS: Over-expression of miR-138-5p significantly reduced the expression of FOXC1 and vimentin at mRNA and protein levels (P<0.05). The expression of E-cadherin and β-catenin were up-regulated and the expression of N-cadherin was down-regulated. The proliferation, migration and invasion abilities of the lung cancer cells were inhibited by the over-expression of miR-138-5p.CONCLUSION: miR-138-5p inhibits the proliferation, migration and invasion abilities of lung cancer cells by targeting FOXC1 and vimentin. It may be a potential target for lung cancer gene therapy.     

MicroRNA-98 suppresses viability and invasion ability of colorectal can-cer cells by targeting EZH2

AIM: To study the target relationship between microRNA-98 (miR-98) and enhancer of Zeste homolog 2 (EZH2), and the effect of miR-98 on the viability and invasion ability of colorectal cancer cells.METHODS: The target relationship between EZH2 and miR-98 was predicted by TargetScan software and confirmed by dual-luciferase reporter assay. The miR-98 mimic and miR-98 inhibitor were transfected into human colorectal cancer SW480 cells and SW620 cells. The protein expression level of EZH2 was determined by Western blot. The cell viability was measured by MTT assay, and the invasion ability was detected by Transwell assay. EZH2 over-expression vector was transfected into the colorectal cancer cells, and the cell viability and invasion ability were measured.RESULTS: miR-98 targeted EZH2 and down-regulated EZH2 protein expression in the SW480 cells and SW620 cells. miR-98 over-expression significantly decreased, while miR-98 knockdown dramatically increased the viability and invasion ability of SW480 cells and SW620 cells. Additionally, EZH2 over-expression enhanced the viability and invasion ability of SW480 cells and SW620 cells.CONCLUSION: miR-98 inhibits the viability and invasion ability of SW480 cells and SW620 cells by targeting EZH2, which may provide new therapeutic target and method for colorectal cancer treatment.     

Effects of microRNA-141 regulating Nrf2/ARE signaling pathways by targeting Keap1 on viability of T47D breast cancer cells

AIM:To investigate the effects of microRNA-141 (miRNA-141) regulating Nrf2/ARE signaling pathways by targeting Keap1 on the viability of T47D breast cancer cells. METHODS:The breast cancer T47D cells were transfected with miRNA-141 mimic and the negative control sequence (negative control, NC), as miRNA-141 group and NC group, respectively, and the cell without transfection was used as control group. Real-time PCR was used to detect the expression level of miRNA-141. The cell viability was measured by MTT assay. Fluorescent probe 2',7'-dihydrodichlorofluorescein diacetate ester (DCFH-DA) was used to detect cell reactive oxygen species (ROS) level. The protein expression levels of Keap1, nuclear factor E2-related factor 2 (Nrf2), superoxide dismutase 2 (SOD2) and glutathione peroxidase 1 (GPx1) were determined by Western blot. Dual luciferase assay was used to analyze relationship between miRNA-141 and Keap1. RESULTS:After the cells were transfected with miRNA-141 mimic, the expression of miRNA-141 was obviously higher in miRNA-141 group than that in other groups (P<0.05). The cell viability, ROS level and Keap1 protein expression were significantly decreased, while the Nrf2 protein in the nucleus and antioxidants SOD2 and GPx1 expression were up-regulated in miRNA-141 group. Moreover, the luciferase reporter assay demonstrated that Keap1 was the target gene of miRNA-141. CONCLUSION:miRNA-141 may negatively regulates Keap1 and activates Nrf2/ARE signaling pathways, which inhibits the viability of breast cancer cells via inducing the expression of antioxidant enzymes to reduce the oxidative stress levels of the cells.     

A 3D cell culture system to study epithelial-mesenchymal transition and drug resistance of lung cancer

AIM To explore the molecular mechanism of transforming growth factor-β1 （TGF-β1）-induced epithelial-mesenchymal transition （EMT） and cisplatin resistance in three-dimensionally cultured lung cancer cells. METHODS Under three-dimensional culture condition, the morphological changes and protein expression changes of human non-small-cell lung cancer 95D cells were observed by inversed fluorescence microscopy, scanning electron microscopy, laser scanning confocal microscopy and Western blot before or after TGF-β1 stimulation. The cisplatin sensitivity was determined by MTT assay. RESULTS Under the three-dimensional culture condition, the structure of 95D cell spheroids after TGF-β1 stimulation collapsed, the cells were dispersed and migrating, and the spheroids merged with each other. The results of laser confocal microscopy showed that E-cadherin protein expression in the 95D cells did not changed after TGF-β1 stimulation, and the protein expression of N-cadherin and vimentin was significantly up-regulated. The results of Western blot showed that the expression of E-cadherin was down-regulated after TGF-β1 stimulation, and the protein levels of N-cadherin, vimentin, phosphorylated AKT and phosphorylated mTOR were up-regulated. LY294002 and rapamycin reversed TGF-β1-induced expression of the above proteins. The results of MTT assay showed that TGF-β1 reduced the sensitivity of three-dimensionally cultured 95D cells to cisplatin, while LY294002 and rapamycin reversed the cisplatin resistance of the 95D cells stimulated by TGF-β1. CONCLUSION TGF-β1 induces the EMT and cisplatin resistance of three-dimensionally cultured lung cancer cells through the activation of PI3K/AKT/mTOR signaling pathway.     

Artesunate enhances anti-tumor activity of gemcitabine on pancreatic cancer through MDM2/p53 pathway

AIM: To explore the effect of artesunate on gemcitabine-dependent anti-tumor activity for pancrea-tic cancer.METHODS: The viability of p53 wild-type pancreatic cancer cell line Capan-2 was measured by MTT assay. The protein levels of murine double minute protein 2 (MDM2), p53, Noxa and Puma, the release of cytochrome C and apoptosis-inducing factor, and the activation of caspase-9 and caspase-3 in the Capan-2 cells were determined by Western blot. The mitochondrial membrane potential and apoptotic rate of the Capan-2 cells were analyzed by flow cytometry.RESULTS: The viability of Capan-2 cells in artesunate plus gemcitabine group was significantly lower than that in single gemcitabine treatment group (P<0.05). Gemcitabine treatment significantly inhibited the expression of MDM2 in the Capan-2 cells. The expression levels of p53, Noxa and Puma in the artesunate plus gemcitabine group were significantly higher than those in single gemcitabine treatment group. Artesunate obviously promoted the apoptosis, the release of cytochrome C and apoptosis-inducing factor, the activation of caspase-9 and caspase-3, and the collapse of mitochondrial membrane potential in the Capan-2 cells treated with gemcitabine. On the other hand, transfection with MDM2 plasmid obviously suppressed the apoptotic pathway of Capan-2 cells which were treated with artesunate and gemcitabine.CONCLUSION: Artesunate enhances the anti-tumor activity of gemcitabine on pancreatic cancer Capan-2 cells through the MDM2/p53 pathway.     

miRNA-126 inhibits proliferation,migration and invasion of human lung cancer A549 cells via EGFR/AKT/mTOR pathway

AIM: To investigate the effects of microRNA(miRNA)-126 on the proliferation, migration and invasion of human lung cancer cell lines, and to explore its mechanism. METHODS: The A549 cells were transfected with miRNA-126 agomir by Lipofectamine 2000. The expression of miRNA-126 was detected by real-time PCR. The cell activity was detected by MTT assay. The number of viable A549 cells was counted by the method of Trypan blue exclusion. The cell colony-forming capability was determined by cell colony formation test. The cell migration and invasion abilities were assayed by wound healing and Transwell methods, respectively. The protein levels of p-EGFR, EGFR, p-AKT, AKT, p-mTOR and mTOR were determined by Western blot. RESULTS: The expression level of miRNA-126 was significantly increased in the A549 cells compared with negative control(NC) group and control group(P<0.01). The proliferation of A549 cells was decreased extremely after transfected with the miRNA-126 agomir(P<0.01), so did the result of the cell colony-formation test. The migration and invasion abilities of the lung cancer cells were also significantly inhibited. The protein levels of p-EGFR, p-AKT and p-mTOR were significantly down-regulated compared with NC group and control group(P<0.01). CONCLUSION: Over-expression of miRNA-126 significantly inhibits the proliferation, migration and invasion ability of human lung cancer A549 cells by down-regulation of EGFR/AKT/mTOR pathway.     

Sphingosine kinase 1 enhances invasion and migration of non-small-cell lung cancer cells by ERK1/2 signaling pathway

AIM To explore the effects of sphingosine kinase 1 (SphK1) on the migration and invasion of non-small-cell lung cancer (NSCLC) cells and its mechanism. METHODS Thirty-one tumor specimens, which were surgically resected and routinely histologically confirmed as NSCLC, and matched adjacent lung tissues were selected. Immunohistochemical staining and RT-qPCR were used to detect the expression of SphK1. The pcDNA3.1-SphK1 vector (SphK1 group), empty pcDNA3.1 vector control (NC group), SphK1 siRNA (siSphK1 group) or control siRNA (siNC group) was transfected into human lung adenocarcinoma A549 cells, and the protein levels of SphK1, E-cadherin, fibronectin and p-ERK1/2 were determined by Western blot. The effects of over-expression of SphK1 and inhibition of ERK1/2 on migration and invasion of A549 cells were evaluated by Transwell assays. RESULTS SphK1 was highly expressed in the NSCLC tissues and was associated with tumor stage. SphK1 over-expression significantly promoted the migration and invasion of A549 cells, increased the protein levels of p-ERK1/2 and fibronectin, and decreased the protein expression of E-cadherin (P<0.05), but the opposite result was observed after SphK1 interference. The ERK1/2 inhibitor U0126 significantly inhibited the up-regulation of p-ERK1/2 and fibronectin levels and the down-regulation of E-cadherin expression induced by SphK1 over-expression, and also inhibited the invasion and migration of A549 cells promoted by SphK1 over-expression (P<0.05). CONCLUSION SphK1 may reduce E-cadherin protein levels, increase fibronectin protein levels, and promote the invasion and migration of NSCLC cells through ERK1/2 signaling pathway.     

miR-140-3p inhibits viability,invasion and migration of non-small-cell lung cancer A549 cells by targeting PD-L1

AIM: To explore the target relationship between microRNA-140-3p (miR-140-3p) and programmed cell death ligand 1 (PD-L1) and their effect on the viability, migration and invasion of non-small-cell lung cancer A549 cells.METHODS: RT-qPCR was used to detect the miR-140-3p expression in HLF-1, A549 and H1299 cells, and then the A549 cells with the most significant difference were selected as the subsequent research object. TargetScan software and dual-luciferase reporter assay were performed to predict and confirm the target relationship between miR-140-3p and PD-L1. RT-qPCR and Western blot were used to determine the effects of miR-140-3p mimic and inhibitor on PD-L1 expression level. MTT assay was used to detect the viability of A549 cells. Transwell assay was performed to detect the migration and invasion abilities of the A549 cells.RESULTS: miR-140-3p was significantly down-regulated in the A549 cells and H1299 cells (P<0.05). Transfection with miR-140-3p mimic decreased the expression of PD-L1 and inhibited the viability, migration and invasion of the A549 cells. Transfection with pcDNA3.0-PD-L1 reversed the inhibitory effect of miR-140-3p on the viability, migration and invasion of the A549 cells.CONCLUSION: miR-140-3p inhibits the viability, migration and invasion of A549 cells by targeting PD-L1.