Preliminary exploration for effect of EphA2 on drug resistance of colorectal carcinoma cells

AIM: To investigate the effect of Eph receptor A2 (EphA2) on drug resistance of colorectal carcinoma cells and its possible mechanisms. METHODS: Real-time PCR and Western blot were used to detect the expression of EphA2 at mRNA and protein levels in LoVo and LoVo/5-FU cells. EphA2 siRNA was transfected to down-regulate the EphA2 expression in LoVo/5-FU cells, and the drug sensitivity was calculated by CCK-8 assay. Meanwhile, cell migration and invasion were measured by wound healing assay and Transwell assay, and the protein levels of E-cadherin, β-catenin, N-cadherin, vimentin, Notch and Snail were determined by Western blot. RESULTS: The expression of EphA2 at both mRNA and protein levels was significantly up-regulated in LoVo/5-FU cells (P<0.05). Knockdown of EphA2 suppressed the cell viability, and migration and invasion abilities, but promoted drug sensitivity of LoVo/5-FU cells. Up-regulation of E-cadherin and β-catenin, and down-regulation of N-cadherin and vimentin were observed, indicating that the epithelial-mesenchymal transition (EMT) process was suppressed. Knockdown of EphA2 decreased the expression levels of Notch and Snail. CONCLUSION: Down-regulation of EphA2 partly reverses drug resistance of LoVo/5-FU cells. The mechanism may be related to suppressing cell growth, migration, invasion and EMT process via Notch/Snail signaling pathway.     

Effect of CD97 gene silencing by small interfering RNA on migration and invasion of gastric carcinoma cell lines

AIM: To investigate the effect of CD97 gene silencing by small interfering RNA(siRNA) on migration and invasion of gastric carcinoma cell lines. METHODS: Gastric carcinoma cell lines AGS and MGC803 were used in the study. Four pairs of siRNA were designed according to the sequence of CD97 gene and synthesized chemically. The siRNAs were transfected into the gastric carcinoma cell lines. Forty-eight hours after transfection, the total RNA was extracted and the mRNA expression of CD97 was detected by real-time RT-PCR so as to screen the most effective siRNA. The protein level of CD97 was also measured by fluorescence-activated cell sorting (FACS) 72 h after Transfection. The abilities of migration and invasion were evaluated by Transwell test. The viability of the cells was measured by MTT method. RESULTS: Real-time RT-PCR and FACS revealed that CD97-siRNA notably down-regulated CD97 expression at both mRNA and protein levels. The mRNA level decreased by (89.34±9.95)% and (95.42±1.93)% in AGS and MGC803 cells,respectively. The protein levels of CD97^EGF and CD97^stalk in AGS cells decreased by (19.29±3.45)% and (30.11±5.93)%,respectively. The protein levels of CD97^EGF and CD97^stalk in MGC803 cells decreased by (26.25±5.73)% and (16.22±3.23)%,respectively. No change of the cell viability after siRNA transfection was observed. The cell number of migration and invasion in AGS cells was decreased by (67.63±12.03)% and (68.02±15.63)%,respectively. The cell number of migration and invasion in MGC803 cells was decreased by (14.92±2.03)% and (22.09±5.43)%,respectively. CONCLUSION: The siRNA effectively inhibits CD97 expression and restrains the migration and invasion capacities of gastric carcinoma cell lines, suggesting that CD97 plays an important role in the metastasis of gastric cancer.     

Effect of specific hTERT RNA interference on biological characteristics of colon carcinoma in vivo and in vitro

AIM: To investigate the effect of specific hTERT RNA interference on biological characteristics of colon carcinoma in vivo and in vitro. METHODS: A small interference RNA (siRNA) targeting to hTERT mRNA (pU6-hTERT-siRNA) was constructed. The siRNA was transfected into LoVo colon cancer cells in vivo and in vitro with Lipofectamine^TM2000. The groups of non-specific siRNA (pU6-hTERT) and non-treatment were designed as negative control and blank control,respectively. The cell growth in vitro was detected by MTT method. The effect of pU6-hTERT-siRNA on xenografts in nude mice was observed by determining the tumor size. The mRNA expression of hTERT in vitro and in vivo was detected by FQ-PCR quantitatively. The protein level of hTERT was determined by Western blotting. RESULTS: The inhibition rate of cell growth in vitro 72 h after transfection with recombinant plasmids containing hTERT-target sequences was 42.1%, significantly higher than that in control group (3.2%, P<0.01). The size of xenografts in pU6-hTERT-siRNA group was (85.9±18.7)mm³, significantly smaller than that in control group and blank group , P<0.01. The mRNA expression and the protein level of hTERT were both specifically inhibited by pU6-hTERT-siRNAs in LoVo colon cancer cells and xenografts (P<0.01). No difference between control group and blank group was observed (P>0.05).CONCLUSION: hTERT expression in LoVo colon cancer cells is inhibited significantly in vivo and in vitro by using plasmid-based siRNA. Down-regulation of hTERT expression distinctly inhibits the growth of LoVo colon cancer cells in vitro or subcutaneously transplanted in athymic mice.     

Effects of G6PD silencing by siRNA on expression of HIF-1α in human colon cancer cells

AIM: To study the effects of glucose-6-phosphate dehydrogenase (G6PD) silencing by small interference RNA(siRNA) on the levels of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) and hypoxia-inducible factor 1α(HIF-1α) under hypoxia in human colon cancer cell line LoVo.METHODS: Specific siRNA expression vector targeting G6PD gene was constructed. The recombinant plasmid was identified by restriction endonuclease and DNA sequencing, and then transfected into LoVo cells. The effects of G6PD silencing were evaluated by detecting the activity and mRNA expression of G6PD. LoVo cells were cultured in vitro under hypoxic condition. NADPH levels were determined.The mRNA and protein levels of HIF-1α were analyzed by RT-PCR and Western blotting,respectively. RESULTS: The recombinant plasmid for G6PD silencing by siRNA was successfully constructed and transfected into LoVo cells. Compared with untransfected cells,the mRNA expression of G6PD in transfected cells was decreased by 43% and G6PD activity was decreased by 63.5%. Under hypoxic condition, the level of NADPH in transfected cells was significantly decreased (41% vs 100%, P<0.05).HIF-1α protein was also decreased significantly but its mRNA expression had no change as compared with the control cells. CONCLUSION: G6PD silencing by siRNA decreases NADPH level, resulting in the decline of HIF-1α stability in cancer cells under hypoxic condition. By this mechanism, G6PD silencing can influence the hypoxic responses in cancer.     

Expression of Gab2 in human osteosarcoma U2-OS cells

AIM: To investigate the expression of Grb2-associated binding protein 2 (Gab2) in human osteosarcoma cells and its relationship with the invasion and metastases of human osteosarcoma cells. METHODS: The technique of small RNA interference was used to transfect human osteosarcoma U2-OS cell lines. Western blotting and RT-PCR were used to detect the protein and mRNA expression of Gab2 in transfected U2-OS cells. After transfection, through chemotaxis and invasion assays in vitro, the cell migration and invasion abilities were detected. RESULTS: After transfection, the expression of Gab2 at mRNA and protein levels in Gab2 siRNA transfected cells (SiGab2/U2-OS) was lower than that in scrambled siRNA transfected cells (Scr/U2-OS) and U2-OS cells. After stimulation with epidermal growth factor (EGF) at concentration of 10 μg/L, the migration SiGab2/U2-OS cells was significantly less than Scr/U2-OS cells and U2-OS cells (P<0.01). The number of invasion cells of SiGab2/U2-OS group was significantly lower than the other 2 control groups (P<0.01). CONCLUSION: Inhibition of Gab2 expression obviously attenuates the migration and invasion abilities of human osteosarcoma U2-OS cell line.     

Effect of silencing hHBrk1 on proliferation and migration of lung carcinoma cells

AIM: To observe the effect of hHBrk1 gene on proliferation and migration of lung carcinoma cells. METHODS: Recombinant plasmids harboring 19-nt-long small interfering RNA (siRNA) were constructed and tested to selectively downregulate hHBrk1 gene in human lung cancer 95D cell line in vitro by stable transfection with Lipofectamine 2000. The mRNA level of the cells transfected with siRNA plasmids were monitored by Northern blotting and RT-PCR. Growth curve and flow cytometry were applied to determine the cell proliferation and cell cycle. Ability of cell migration was measured by Trans-well system. RESULTS: hHBrk1 gene was silenced by targeting siRNA, and stable silencing cell model was constructed. No difference in proliferation and clone formation between hHBrk1 silencing cells and control cells was observed. The ability of migration was decreased in hHBrk1 silencing cells as compared with control cells. CONCLUSION: hHBrk1 may play an important role in migration of the lung cancer cells.     

Role of translationally controlled tumor protein in PRL-3-promoted metastasis of colon cancer cells

AIM: To study the role of translationally controlled tumor protein (TCTP) in the proliferation, migration and invasion of phosphatase of regenerating liver-3(PRL-3)-promoted colon cancer cells.METHODS: The vectors pAcGFP-C3 and pAcGFP-C3-PRL-3 were constructed and transfected into the colon cancer cell line LoVo.LoVo-PRL-3 cells stably expressing PRL-3 and LoVo-control cells were established. The expression levels of PRL-3 and TCTP in both cells were detected by Western blotting and real-time PCR. The specific siRNA sequence for TCTP mRNA and control-siRNA were synthesized and transfected into the LoVo-PRL-3 cells. TCTP expression at mRNA and protein levels in LoVo-PRL-3 was detected by Western blotting and real-time PCR 24 h, 48 h and 72 h after transfection. The proliferation, migration and invasion abilities of LoVo-control cells, LoVo-PRL-3 cells, TCTP-siRNA and control-siRNA cells were detected by CCK-8 assay and the method of Transwell cell culture chambers.RESULTS: The expression of TCTP at mRNA and protein levels in LoVo cells was significantly increased after PRL-3 transfection (P<0.05). TCTP mRNA was significantly inhibited 24 h, 48 h and 72 h after transfection of TCTP-siRNA (P<0.01). TCTP protein was also significantly inhibited 48 h and 72 h after transfection (P<0.01). Compared with LoVo-control cells, the proliferation, migration and invasion abilities of LoVo-PRL-3 cells were significantly enhanced (P<0.05). However, lowering the up-regulated expression of TCTP in LoVo-PRL-3 cells inhibited the proliferation, migration and invasion abilities (P<0.05). CONCLUSION: PRL-3 promotes proliferation, migration and invasion of colon cancer cells by up-regulating the TCTP expression. siRNA targeting TCTP may be an effective method for prevention and treatment of colon cancer cell metastasis.     

RNAi-mediated knocking-down of LBH gene promotes cell cycle progress in 16HBE cells

AIM: To investigate the effect of small interfering RNA(siRNA) on limb-bud and heart(LBH) gene expression in 16HBE cells, and further to observe the change of 16HBE cell cycle after knocking down of LBH gene. METHODS: Synthetical siRNA targeting LBH gene was transfected into 16HBE cells by the method of lipofectamine 2000. The mRNA expression of LBH was examined by real time RT-PCR. The cell cycle was assayed by flow cytometry. The expression of cyclin E1 and E2 was also detected by real time RT-PCR and Western blotting.RESULTS: The expression of LBH gene decreased by 86% in 16HBE cells transfected with 50 nmol/L of siRNA for 48 h. After transfected with siRNA for 48 h, 16HBE cells in G₁ phase decreased by 9.28% and the cells in S phase increased by 14.08%. The expression level of cyclin E2 in 16HBE cells transfected with siRNA was twice higher than that of the negative control cells.CONCLUSION: Sequence-specific siRNA targeting LBH is capable of suppressing LBH gene expression in 16HBE cells. Down-regulation of LBH expression in 16HBE cells may promote the progress of cell cycle, and up-regulation of cyclin E2 expression plays a role in the process of G₁/S phase.     

Effects of BCL6B on proliferation and migration of human colorectal carcinoma LoVo cells and its potential mechanism

AIM: To detect the endogenous expression of B-cell leukemia/lymphoma 6 member B (BCL6B) in FHC and LoVo cells, and to investigate the effects of BCL6B on proliferation and migration of LoVo cells for further exploring the underlying mechanism. METHODS: The endogenous expression of BCL6B in the FHC and LoVo cells was detected by RT-PCR and Western blot. The methods of MTT assay, colony formation assay, wound healing assay and Transwell chamber experiment were employed to examine the biological functions of BCL6B in the LoVo cells. The mRNA and protein levels of BCL6B, cyclin D1 and matrix metalloproteinase-9 (MMP-9) were determined by RT-PCR and Western blot, respectively. The level of phosphorylated protein kinase B (p-AKT) was detected by Western blot. RESULTS: BCL6B expression was notably repressed in the LoVo cells as compared with the FHC cells, which were significantly increased by transfection with pcDNA3.1-BCL6B. The abilities of proliferation and migration of the LoVo cells at 72 h were inhibited by 28.33%(P<0.01) and 36.11%(P<0.05) in BCL6B group. The mRNA levels of cyclin D1 and MMP-9 in the cells of BCL6B group were decreased by 39.90%(P<0.01) and 77.36% (P<0.05), and the protein levels of cyclin D1, MMP-9 and p-AKT were reduced by 44.00%(P<0.05), 47.06%(P<0.01) and 32.88% (P<0.05), respectively. CONCLUSION: BCL6B inhibits proliferation and migration of the LoVo cells, and the PI3K/AKT signaling pathway is involved in this process.     

Influence of siRNA-mediated MIF knockdown on inhibition of inflammatory lipid mediator release by glucocorticoids

AIM：To investigate the influence of siRNA-mediated macrophage migration inhibitory factor (MIF) knockdown on inhibition of inflammatory lipid mediator release by glucocorticoids.
METHODS：Mouse macrophage cell line RAW2647 was transiently transfected with MIF siRNA and control siRNA by liposome method. The transfection efficiency was assessed by immunofluorescence technique. The expression of MIF mRNA and protein was examined by RT-PCR and Western blotting, respectively. Prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) production in cell culture supernatants was measured by ELISA, and the protein expression of Annexin 1, cytosolic phospholipase A2α (cPLA2α) and phospho-cPLA2α were evaluated by Western blotting.
RESULTS：MIF siRNA significantly inhibited MIF expression both at mRNA and protein levels in RAW2647 cells and subsequently enhanced the inhibitory effect of dexamethasone (Dex) on PGE2 and LTB4 production. MIF siRNA also increased Annexin 1 expression becreased by Dex, and strengthened the inhibitory effect of Dex on the phosphorylation of cPLA2α.
CONCLUSION：MIF siRNA enhances the inhibitory effect of Dex on PGE2 and LTB4 production from RAW2647 cells partly via increasing Annexin 1 expression and inhibiting cPLA2α phosphorylation. Intracellular MIF knockdown mediated by siRNA may enhance the sensitivity of RAW2647 cells to the anti-inflammatory effect of glucocorticoids.     

Effect of ABCE 1 gene silencing on proliferation and migration of human bladder cancer cell line T24

AIM: To investigate the effect of small interfering RNA (siRNA)-mediated ABCE1 knockdown on the survival, cell cycle and invasion of human bladder cancer cell line T24. METHODS: The siRNA against ABCE1 was constructed and transfected into the T24 cells with Lipofectamine^TM 2000. The expression of ABCE1 was detected by RT-PCR and Western blot. Flow cytometry was used to detect the cell cycle. The effects of ABCE1 gene silencing on proliferation, migration and invasion of T24 cells were evaluated by CCK-8 assay, wound-healing assay and Transwell invasion assay, respectively. RESULTS: Compared with control group and blank group, the mRNA and protein levels of ABCE1 were significantly decreased in experimental group after transfected with ABCE1 siRNA. The cell cycle was arrested at G₀/G₁ phase and the cell number in S phase was decreased in the T24 cells. Compared with control group and blank group, the proliferation of T24 cells in experimental group was inhibited significantly, and the migration and invasion abilities of T24 cells in experimental group decreased significantly. CONCLUSION: Knockdown of ABCE1 gene may decrease migration, invasion and proliferation abilities in T24 cells.     

Growth-inhibitory effects of selective cyclooxygenase-2 inhibitor on colon cancer cells and its possible mechanisms

AIM: To evaluate the growth-inhibitory effects of NS-398, a selective cyclooxygenase-2 inhibitor, in human colon cancer HT-29 cells and its possible mechanisms. METHODS: MTT assay was applied to detect the cell proliferation. Flow cytometry was performed to detect apoptosis rate and cell cycle. RT-PCR was used to detect the expression of bcl-2 mRNA and bax mRNA. Alteration of cytoskeleton component F-actin was observed by confocal laser scanning microscope. RESULTS: NS-398 could inhibit growth of HT-29 cells in dose-and time-dependent manners. Flow cytometry revealed that NS-398 could induce apoptosis and cause G0/G1 arrest of HT-29 cells in a dose-dependent manner. After 72 h incubation with NS-398 at different concentrations, the expression level of bcl-2 mRNA was lowered and the ratio of bcl-2 to bax was decreased in HT-29 cells. F-actin was mainly distributed around nuclei forming annular structure in HT-29 cells. After exposure to NS-398, the annular structure around nuclei disappeared and fluorescence intensity of F-actin decreased obviously. CONCLUSION: NS-398 can inhibit the growth effectively and induce apoptosis in HT-29 cells in vitro, which is associated with the down-regulation of bcl-2 to bax ratio and the disruption of cytoskeleton.     

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.     

Effect of long non-coding RNA MEG3 on invasion and migration of colorectal cancer cells

AIM: To investigate the expression of long non-coding RNA maternally expressed gene 3(MEG3) in colorectal cancer(CRC) cells, and to observe the effect of MEG3 on the invasion and migration of CRC cells. METHODS: The levels of MEG3 in human normal colon cell NCM460 and CRC cells SW48 and LoVo were detected by real- time PCR. MEG3 was over-expressed by plasmid transfection, and the effects of MEG3 on the invasion and migration of SW48 and LoVo cells were analyzed by Transwell assay and wound healing assay. The expression of matrix metalloproteinase(MMP) family proteins was determined by Western blotting. RESULTS: The level of MEG3 was down-regulated in CRC cells compared with normal colon cell NCM460. The invasion and migration of CRC cells were reduced after MEG3 over-expression. Transwell invasion and migration assays showed that the numbers of transmembrane SW48 and LoVo cells were smaller in MEG3 over-expression group than control group(CONCLUSION: The expression of MEG3 is down-regulated in CRC cells. Over-expression of MEG3 inhibits the invasion and migration of CRC cells. TIMP-2, MMP-2 and MMP-9 might play an important role in this regulation.     

Screening of differentially expressed genes in colorectal cancer based on TCGA database and verification of novel gene CCDC78

AIM To explore novel genes closely related to the prognosis of colorectal cancer through bioinformatics analysis of RNA sequencing (RNA-Seq） data of gene expression profile in large samples of colorectal cancer tissues from The Cancer Genome Atlas (TCGA) database, and to validate the new genes and study their functions. METHODS The RNA-Seq data were downloaded from TCGA database to screen differentially expressed genes, R-survival package was used to carry out survival analysis of differentially expressed genes to screened out genes related to prognosis of colorectal cancer, and the most significantly up-regulated genes that have not been reported in cancer studies were selected for further verification. RT-qPCR was employed to detect mRNA expression of these novel genes in human colon cancer cell lines and human colorectal cancer tissues. The colon cancer cell line with stable silencing of the novel gene expression was constructed by transfection of lentivirus vector, and its viability, migration and invasion were detected by CCK-8 assay and Transwell assay. RESULTS (1) A total of 4 017 differentially expressed genes were found in the gene expression profile of the colorectal cancer samples. Kaplan-Meier survival analysis showed that 69 genes were closely related to poor prognosis in patients with colorectal cancer, 36 of which were up-regulated, and 11 of these 36 genes have not been reported in cancer studies. (2) The mRNA expression of the top 3 up-regulated genes CCDC78, PGGHG and TSPEAR of the 11 genes was significantly increased in colon cancer cell lines, and the expression of CCDC78 mRNA was also up-regulated in colorectal cancer tissues. (3) CCDC78 gene silencing significantly suppressed the viability, migration and invasion of colon cancer cells (P<0.01). CONCLUSION Bioinformatics analysis based on TCGA database is helpful to discover nov?el genes related to prognosis of colorectal cancer, and CCDC78 may be a novel oncogene associated with poor prognosis of colorectal cancer.     

Long noncoding RNA MALAT1 regulates Rac1b expression and is associated with colorectal cancer metastasis

AIM: To investigate the role of MALAT1 in colorectal cancer metastasis.METHODS: The mRNA expression levels of MALAT1 and Rac1b in the tumor and adjacent normal tissues were examined by real-time PCR. MALAT1 was knocked down by siRNA in colorectal cancer cell lines. The expression of Rac1b and the epithelial-mesenchymal transition markers was examined by Western blot. Cell proliferation was determined by EdU analysis. The effects of MALAT1 on the cell migration and invasion were examined by Transwell assay. RESULTS: The expression of MALAT1 was down-regulated in colorectal cancer. Down-regulation of MALAT1 induced Rac1b overexpression, which in turn increased the expression levels of E-cadherin and β-catenin. Furthermore, down-regulation of MALAT1 promoted the cell proliferation, invasion and migration. CONCLUSION: MALAT1 is associated with metastasis of colorectal cancer through regulating the expression of Rac1b and the downstream factors.     

Effects of propofol on biological characteristics of colorectal cancer cells

AIM: To investigate the effect of propofol on the viability, invasion ability and apoptosis of colorectal cancer cells.METHODS: Propofol at 10, 25, 50 and 100 μmol/L was used to treat LoVo cells for 72 h, and propofol at 100 μmol/L was used to treat the LoVo cells for 12, 24, 48 and 72 h. The cell viability was measured by CCK-8 assay. The invasion ability of the LoVo cells treated with propofol at 100 μmol/L for 72 h was detected by Transwell assay. The cell cycle distribution and cell apoptotic rate were analyzed by flow cytometry. The protein levels of matrix metalloproteinase (MMP)-2, MMP-9, cleaved caspase-3, Notch1 and hairy and enhancer of split 1 (Hes1) were determined by Western blot.RESULTS: Propofol inhibited LoVo cell viability. The cell invasion ability, S stage cells, and the protein levels of MMP-2, MMP-9, Notch1 and Hes1 in propofol group were significantly lower than those in control group, and the apoptotic rate, G₀/G₁ cells and the protein level of cleaved caspase-3 were significantly higher than those in control group (P<0.01).CONCLUSION: Propofol inhibits the viability and invasion ability of colorectal cancer LoVo cells, blocks cell cycle and induces apoptosis. The mechanism is related to down-regulation of Notch1 signaling pathway.     

Knockdown of astrocyte elevated gene-1 by siRNA inhibits cell proliferation and induces apoptosis in human neuroblastoma cell line

AIM: To investigate the effect of siRNA-induced astrocyte elevated gene-1 ( AEG-1 ) down-regulation on the proliferation, apoptosis and cell cycle of neuroblastoma cells. METHODS: An siRNA targeting to AEG-1 mRNA (AEG-1 siRNA) was constructed and transfected into neuroblastoma cells with Lipofectamine 2000. A non-specific siRNA (control siRNA) and non-treatment were used as negative control and blank control,respectively . The cell proliferation was detected by MTT method and colony formation assay. The apoptosis and cell cycle were analyzed by flow cytometry. RESULTS: Compared with control groups, the expression of AEG-1 mRNA was evidently declined in the cells transfected with AEG-1 siRNAs (P<0.05). AEG-1 siRNA significantly decreased the cell proliferation. After treated with AEG-1 siRNA for 48 h, the percentage of apoptotic cells was significant increased and the cell cycle was arrested in G₀/G₁ phase compared with the control cells (P<0.05). CONCLUSION: The mRNA expression of AEG-1 is down-regulated by AEG-1 siRNA in neuroblastoma cells. Knockdown of AEG-1 expression in human neuroblastoma cells significantly inhibits cell proliferation and apoptosis, and induces cell arrest in G₀/G₁ phase of the cell cycle.