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.     

Inhibitory effect of survivin-siRNA on prostatic subcutaneous xenografts in nude mice

AIM: To investigate the inhibitory effect of survivin-siRNA recombinant plasmid on prostate cancer xenografts. METHODS: Prostatic cancer DU145 cells were cultured and subcutaneously injected into nude mice. When the tumor grew to 8 mm in diameter, it was aseptically removed and divided into about 2 mm blocks through surgery and subcutaneously implanted into another nude mice. After the prostatic cancer xenograft model was reconstructed, the mice were treated with survivin-siRNA plasmid and control scrambled siRNA plasmid using electric transfection method. The tumor growth curve was plotted and the inhibitory rate was calculated. HE staining, immunohistochemical staining and TUNEL assay were applied to observe the effect of survivin-siRNA on the xenografts. RESULTS: The prostatic cancer xenograft model was successfully constructed in vivo. Compared with mock and scrambled siRNA groups, transfection of survivin-siRNA recombinant plasmid obviously inhibited the tumor growth with the inhibitory rates of 61.81% and 62.87%, respectively. Compared with both controls, survivin-siRNA depressed the protein expression of survivin and promoted the cell apoptosis. CONCLUSION: Survivin-siRNA recombinant plasmid significantly inhibits the growth of prostatic tumor xenografts by inhibiting the protein expression of endogenous survivin and promoting cell apoptosis.     

Nucleostemin specific RNAi influences cell proliferation in HeLa cells in vitro and in vivo

AIM: To examine Nucleostemin (NS) expression in tumor cells, and observe the effect of NS specific RNA interference on the cell proliferation in Hela cells. METHODS: Total RNA was extracted from 6 kinds of cultured tumor lines, the NS expression level was measured by RT-PCR and Northern blot. An NS-specific siRNA expression vector was constructed to transfect HeLa cell (NS-siRNA-HeLa), and the proliferation of the cell was observed. RESULTS: NS was highly expressed in 6 kinds of tumor cells. NS expression level in the NS-siRNA-HeLa cells was remarkably reduced, and the percentage of G0/G1 cells increased. The neoplasm forming ability in nude mice by the NS-siRNA-HeLa cells was decreased. CONCLUSION: NS is highly expressed among tumor cells. NS-specific siRNA inhibits the entry of the cell cycle into the S phase, and remarkably reduces the proliferation ability of HeLa cells in vitro and in vivo.     

Relationship between EGFR/HER2 gene knocked down and the downstream signal pathway in SPC-A-1

AIM: RNAi technique was applied to explore the relationship between downstream signal pathway in EGFR family and the cell proliferation, cell cycle alteration, apoptosis after EGFR/HER2 RNA interference. METHODS: Sequence-specific siRNA for EGFR and HER2 were designed as literatures described. “Tuschl rules” and BLAST on the full length of EGFR/HER2 cDNA were used to ensure the sequence-specific siRNA for EGFR/HER2 joint interference. Based on the above sequence-specific siRNA, recombinant plasmids with GFP and neomycin resistance marker were constructed. Six groups including mock, negative control, shRNA-EGFR, shRNA-HER2, shRNA-EGFR/HER2 and shRNA-EGFR+shRNA-HER2 were established by transient transfection. Real time quantitative RT-PCR was used to detect the silencing of the EGFR/HER2 gene level. Western blotting was used to measure the levels of EGFR/HER2 protein and protein phosphorylation expression. Transfected cells were stimulated with EGF 15 min before protein extraction. MTT assay and flow cytometry were used to evaluate the cell proliferation, apoptosis and cell cycle distribution after RNAi. The protein expression levels of downstream signaling pathway proteins including Akt, p-Akt, p-Erk1/2, p-p38 were measured by real time quantitative RT-PCR and Western blotting. Randomized block analysis of variance and SNK methods were used to compare the differences between groups. RESULTS: Cell proliferation was inhibited in the groups of shRNA-EGFR, shRNA-HER2, shRNA-EGFR+shRNA-HER2 and shRNA-EGFR/HER by MTT assay. Cell cycle analysis by flow cytometry showed that apoptosis ratio in shRNA-HER2 (P<0.01), shRNA-EGFR/HER2 (P<0.01) and shRNA-EGFR+shRNA-HER2 (P<0.05) groups were significantly higher than those in negative control group, while there was no statistical difference between shRNA-EGFR and negative control (P>0.05), and that the distributions in phase G1 and phase S in shRNA-EGFR (P<0.01), shRNA-HER2 (P<0.01), shRNA-EGFR/HER2 (P<0.01) and shRNA-EGFR+shRNA-HER2 (P<0.01) were significantly different compared with the negative control. The level of EGFR/HER2 protein and protein phosphorylation expression were down regulated. The cell proliferation, apoptosis and cell cycle alterations induced by EGFR/HER2 RNA interference showed no significant relationship with downstream signal pathway molecular in EGFR family. CONCLUSION: EGFR gene knockdown may not cause significant apoptosis in SPC-A-1 cell line. The variations of cell proliferation, apoptosis and cell cycle alterations induced by EGFR/HER2 RNA interference were not found to have significant relationship with downstream signal pathway molecules in EGFR family.     

Effect of RNA interference on HIF-2 in the renal cancer cell line 786-0

AIM: To study the effect of RNA interference on hypoxia-inducible factor-2 (HIF-2) in the renal cell cancer in vitro and in vivo. METHODS: HIF-2 RNAi was synthesized and inserted into RNA interference eukaryotic expression vector which was confirmed by sequencing. The vector was transfected into the renal cancer cell 786-0 and positive clone was selected by using G418. The HIF-2 expression was detected by RT-PCR and Western blotting method. The growth of cells was measured by MTT method. Nude mouse xenograft assays were also done. RESULTS: Compared with empty vector group and control group, the amounts of HIF-2 mRNA and protein expression were lower in the HIF-2 RNAi group, the difference was significant (P<0.01). No significant difference between empty vector group and control group was observed. The cell growth in the HIF-2 RNAi group become slower. Compared with control group, the growth of tumor was slower in the RNAi group in the nude mice (P<0.01). CONCLUSION: HIF-2 RNAi inhibits the expression of 786-0 and cell growth, and slows the growth of tumor in the nude mice. The result provides new application for biological therapy in the renal cell cancer.     

Effect of specific hTERT-siRNA on growth of human tongue cancer cells in vivo and in vitro

AIM: To investigate the effect and mechanisms of siRNA-hTERT-induced inhibition of Tca8113 tongue cancer cells in vitro and in vivo. METHODS: A small interference RNA (siRNA) targeting to hTERT mRNA (siRNA-hTERT1) was constructed. The siRNA was transfected into Tca8113 tongue cancer cells in vivo and in vitro with cationic liposome. A non-specific siRNA (siRNA-hTERT2) and non-treatment were used as negative control group and blank group. The cell growth in vitro was detected by MTT method. The cell apoptosis in vitro was analyzed by flow cytometry. The effect of siRNA-hTERT1 on xenografts in nude mice was observed by determining the tumor size. The cell apoptosis in xenografts was analyzed by Hoechst staining. The expressions of hTERT mRNA in vitro and in vivo were detected by RT- PCR. RESULTS: The inhibition rates of cell growth in vitro 72 h after siRNA-hTERT1 treatment was 47.2％, significantly higher than that in siRNA-hTERT2 treatment group (2.6％, P<0.01). The cell apoptosis rate was 27.30%±0.18% in vitro, significantly increased at 48 h after transfection of siRNA-hTERT1, compared to negative control group and blank group (P<0.01). The size of xenografts in siRNA-hTERT1 treatment group was (298.8±138.7)mm3, significantly smaller than that in siRNA-hTERT2 treatment group and blank group (495.1±151.6)mm3 and (506.8±207.4)mm3, the inhibition rate was 40.0% (P<0.01). The numbers of apoptotic cells in xenografts significantly increased after transfection of siRNA-hTERT1, compared to negative control group and blank group (P<0.01). Compared to negative control group and blank group, the expression of hTERT mRNA in Tca8113 tongue cancer cells in vitro and in vivo was inhibited by siRNA-hTERT1. CONCLUSION: siRNA-hTERT1 powerfully inhibits the growth of Tca8113 tongue cancer cells in vitro and in vivo. The specific inhibition of hTERT mRNA expression and cell apoptosis may be its main mechanisms.     

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.     

The suppressive effects of IFN-α on human gastric carcinoma cell line BGC-823

AIM:To observe the inhibitory effect of interferon-α (IFN-α) on the growth invasiveness and metastasis of human gastric carcinoma cell line BGC-823,and mechanism of its action.METHODS:We detected the influence of IFN-α on the proliferative ability of BGC-823 in cell culture system,the cell vitality with the MTT colorimetric assay,and the cell cycle with flow cytometer (FCM).The regulatory functions of IFN-α to the expression of E-cadherin and matrix metalloproteinase-2 (MMP-2) in tumor cells were estimated by immunohistochemical analysis (S-P).The ultrastructural changes of the junction among the tumor cells were observed under electron microscope.RESULTS:IFN-α can significantly inhibit the growth of human gastric carcinoma cell line BGC-823 in a dose-dependent manner.When the concentration of IFN-α was ≥106 U/L,the cell proliferation can be effectively suppressed，the suppression rate was ≥12.2%,and the blockage appeared at the phase of G1-S of the cell cycle.Under the induction of IFN-α,the expression level of the cell E-cadherin increased while the MMP-2 decreased.The changes on ultrastructure of the cells showed the increased adhesive junctions and the relative compact structure.CONCLUSION:IFN-α can suppress the growth of human gastric carcinoma cell line BGC-823 through its influence on cell cycle.IFN-α can regulate the expression of E-cadherin and MMP-2,make the cell junction closely,so that it has the potential on restricting the invasion and metastasis of gastric carcinoma cells.     

Knockdown of survivin expression using siRNA inhibits the growth of PC-3M cells

AIM: To study the inhibitory effects of survivin siRNAs on the growth of PC-3M cells. METHODS: Two pairs of DNA template coding siRNA against survivin were synthesized to construct two recombinant plasmids, pSi-sur1 and pSi-sur2. The two recombinants and the two controls, lipofectin and vacant plasmid were transfected into PC-3M cells. The expressions of survivin mRNA and protein were detected respectively by RT-PCR and Western blotting. Proliferation abilities were measured by MTT, and the cell cycle and apoptosis were assayed by FCM. RESULTS: After 72 h of transfection, the level of cell survivin mRNA in the two siRNA groups was 48%±6% (n=3) and 30%±5% (n=3) of that in lipofectin group, and expression of survivin protein were 38%±4% (n=3) and 36%±4% (n=3) respectively of that in lipofectin control. The proliferation rate of cells in pSi-sur1 and pSi-sur2 groups was also inhibited according to MTT, about 44.20%±2.08% (n=3) and 39.20%±1.93% (n=3) of that in lipofectin group. Cell numbers of G1 phase in two siRNA groups were significantly higher than that in two controls, while cells of G2 phase and S phase were much lower. Cell apoptosis was found in both siRNA groups. CONCLUSION: The two survivin siRNA significantly inhibit the expression of survivin in mRNA and protein levels, arrest the cell cycle in G1 phase, and suppress the growth of PC-3M cells and induce apoptosis in vitro.     

Effect of RNA interference on Polo-like kinase-1 in A549 cells

AIM: To investigate whether RNA interference(RNAi) induced by small interference RNA(siRNA) could suppress Polo-like kinase-1 (Plk 1) expression and its effects in A549 cells.METHODS: A recombinant plasmid containing siRNA targeting Plk1 (psiRNA-hH1-Plk1) was transfected into A549 cells with Lipofectamine 2000.Expressions of Plk1,cyclin B1 and p53 protein were detected by Western blotting.Cell proliferation was evaluated by direct cell counting,while cell cycle and apoptosis were examined by flow cytometry,and expression of α-tubulin was detected by immunofluorescence.RESULTS: The results demonstrated that sequence specific siRNA targeting Plk1 was capable of suppressing Plk1 expression,and reflecting in lower kinase activity in A549 cells.The level of Plk1 protein was reduced by at least 70% after 48 h of psiRNA-hH1-Plk1 treatment relative to controls.Expressions of cyclin B1 and p53 were increased greatly after Plk1 depletion,and cells showed absence of microtubule polymerization and spindle abnormalities in staining for α-tubulin.Growth inhibition,G₂/M arrest and apoptosis were observed in psiRNA-hH1-Plk1 transfected group.CONCLUSION: All these data suggest that siRNA targeted against human Plk1 may be a valuable tool in cancer therapy.     

Effect of hPTTG1 siRNA on proliferation and apoptosis of ovarian cancer cells

AIM: To observe the proliferation and apoptosis of ovarian cancer cells by silencing the expression of human pituitary tumor-transforming gene 1 ( hPTTG1 ) using RNA interference technique.METHODS: The chemically synthesized siRNA targeting hPTTG1 was transfected into ovarian cancer cell line A2780 in vitro. The expression levels of hPTTG1 and c-myc were examined by RT-PCR and Western blotting. Cell proliferation was measured by MTT colorimetric assay and -TdR incorporation test. Cell apoptosis was detected by flow cytometry with annexin V/PI and TUNEL labeling.RESULTS: The expression of hPTTG1 at mRNA and protein levels was inhibited after transfection of hPTTG1 siRNA. The inhibitory efficiency was 70.5%±3.9% and 63.8%±4.5%, respectively. The absorbance began to decrease 24 h after transfection of hPTTG1 siRNA,and the highest inhibitory rate was 42.9%±5.2% at 48 h post-transfection. Radioactive incorporation of -TdR in hPTTG1 siRNA group was lower than that in normal and negative groups. The survival rate declined while the apoptotic rate and necrotic rate increased in hPTTG1 siRNA group. Apoptotic index in hPTTG1 siRNA group was higher than that in normal and negative groups. The expression of c-myc at mRNA and protein levels was down-regulated.CONCLUSION: Cell proliferation is inhibited and cell apoptosis is induced by hPTTG1 siRNA through down-regulating the expression of c-myc. hPTTG1 can be regarded as a candidate gene for ovarian cancer gene therapy.     

Effect of Beclin 1 RNA interference on Vit K3 injured SMMC-7721 cells

AIM: To observe the effect of Beclin 1 silencing by RNA interference (RNAi) technique to the injury of SMMC-7721 hepatoma cells by vitamin K3 (Vit K3).METHODS: The recombinant plasmid Psilencer 3.1-siRNA-Beclin 1 was transfected into SMMC-7721 hepatoma cells by eukaryotic cell transfection technique. Plasmid vector and cell culture medium were used as negative and control, respectively. The cells were collected 48 h later to extract cell RNA and total protein and to detect Beclin 1 gene expression by RT-PCR and Western blotting. 40 μmol/L Vit K3 was used to treate the Beclin 1-siRNA cells, Hoechst33342 staining was used for the determination of the percentage of cell apoptosis.RESULTS: Compared with the control group, the synthetic siRNA of Beclin 1 significantly decreased the levels of Beclin 1 mRNA and protein expressions. Beclin 1 mRNA was up-regulated in 40 μmol/L Vit K3 treated SMMC-7721 hepatoma cells, the percentage of apoptosis cells increased (P﹤0.01). In beclin 1-siRNA cells, Beclin 1 mRNA was down-regulated obviously, the percentage of apoptosis cells increased significantly compared with the 40 μmol/L Vit K3 group (P﹤0.01).CONCLUSION: The transfection of SMMC-7721 hepatoma cells by Psilencer3.1-siRNA-Beclin 1 effectively inhibits the expressions of Beclin 1 mRNA and protein, inhibits the activation of Beclin 1 dependent autophagic signaling pathway, and aggravates the apoptosis induced by Vit K3.     

Dihydroartemisinin enhances antitumor effect of 5-fluorouracil against gastric cancer by down-regulating SIRT1 expression

AIM: To investigate the effect of dihydroartemisinin (DHA) adjuvant treatment on enhancing the antitumor effect of 5-fluorouracil (5-FU) against gastric cancer. METHODS: The gastric cancer BGC-823 cells were divided into control group, DHA group, 5-FU group, 5-FU+DHA group and 5-FU+DHA+SIRT1 plasmid group. The viability of BGC-823 cells treated with DHA and 5-FU was measured by MTT assay. The expression of SIRT1 and NADPH oxidase, activation of caspase-9 and caspase-3, and phosphorylation of ASK1 and JNK in the BGC-823 cells treated with DHA and 5-FU were determined by Western blot. The production of ROS and the apoptosis of the BGC-823 cells treated with DHA and 5-FU were analyzed by flow cytometry. RESULTS: Dihydroartemisinin significantly inhibited the expression of SIRT1 and increased NADPH oxidase protein level (P<0.05). DHA increased the sensitivity of BGC-823 cells to 5-FU, thus decreasing the IC₅₀ of 5-FU to the gastric cancer cells. However, transfection with SIRT1 plasmid decreased the cytotoxicity of DHA and 5-FU co-treatment to the BGC-823 cells. DHA promoted the production of ROS and phosphorylation of ASK1 and JNK induced by 5-FU in the BGC-823 cells (P<0.05). However, ROS scavenger N-acetylcysteine (NAC) or JNK specific inhibitor SP600125 inhibited the cell death and activation of caspase-9 and caspase-3 induced by DHA and 5-FU co-treatment (P<0.05). In addition, NAC significantly inhibited the phosphorylation of JNK in the BGC-823 cells co-treated with DHA and 5-FU. However, treatment with SP600125 did not influence the ROS production in the BGC-823 cells, indicating that JNK was the downstream target of ROS pathway. CONCLUSION: Combination of DHA with 5-FU induces caspase-dependent apoptosis in gastric cancer cells through the SIRT1/NADPH oxidase/ROS/JNK signaling pathway.     

Combined targeting blockage of miR-29b/92b/106b inhibits gastric can-cer cell growth and migration

AIM: To investigate the metastasis-associated microRNAs (miRNAs, miR) in gastric cancer, and to determine their biological and therapeutic roles in this malignancy. METHODS: The tumor tissue samples from gastric cancer patients with or without lymph node metastasis were collected (n=3 each). miRNA microarray was used to determine the metastasis-associated miRNAs. Gastic cancer cell line BGC-823 was transfected with locked nucleic acidmodified antisense oligonucleotides of candidate miRNAs and subsequently used for functional assays including CCK-8 assay, flow cytometry, wound healing assay and Transwell migration assay. Furthermore, the in vivo xenograft mice were used to evaluate the tumor suppressive effect of collaborative inhibition of the candidate miRNAs. RESULTS: miR-29b, miR-92b and miR-106b were up-regulated in the tumor tissues from the gastric cancer patients with lymph node metastasis. The functional assays showed that blockage of miR-29b, miR-92b and miR-106b by antisense oligonucleotides in the BGC-823 cells significantly inhibited cell growth and migration, and induced apoptosis. Furthermore, the collaborative inhibition of these triple miRNAs remarkably suppressed tumor growth in vivo. CONCLUSION: miR-29b, miR-92b and miR-106b are metastasis-associated miRNAs. These miRNAs may provide promising therapeutic targets in gastric cancer.     

Effects of p21siRNA on cell cycle uncoupling and apoptosis

AIM:To investigate the effects of P21 protein on cell cycle uncoupling and cell apoptosis with RNA interference assay. METHODS:The expression of P21 protein in HeLa cells was induced by mitomycin (MMC). Lipofect transfection assay was used to take the p21 siRNA into HeLa cells and MMC was given 48 h after transfection. FCM assay was applied to detect the expression of P21 and ratio of polyploid cells and apoptosis. RESULTS:p21 siRNA plasmid interfered the expression of P21 protein in HeLa cells. The number of 2 haploid cells was decreased obviously (P<0.01). The number of 4 haploid and 8 haploid cells was increased significantly (P<0.01) compared with control plasmid 24 and 48 h after MMC was given. CONCLUSION:p21 siRNA silenced the P21 protein and cell death in HeLa cells was induced by p53-independent pathway in the condition of lower expression of P21 protein. The mechanism may be related to cell cycle uncoupling and apoptosis by p53-independent pathway.     

Effects of MAGEA3 inhibition by shRNA on apoptosis in human hepatocellular cancer cells

AIM:To investigate the inhibitory effect of vector-based RNA interference ( RNAi) on the expression of melanoma associated antigen A3 (MAGEA3) protein in hepatocellular carcinoma cells and on apotposis of hepatocellular carcinoma cells. METHODS:A vector for transcribing specific small hairpin RNA ( shRNA) targeting MAGEA3 gene was constructed ,introduced into hepatocellular carcinoma MEL-ED1 cells by Lipofectamine 2000. The MAGEA3 protein and mRNA expression levels of MEL-ED1 cells were detected by Western blotting and RT-PCR, respectively. The cell apoptosis was studied by DNA fragmentation, electron microscopy ，TUNEL assay, and annexin V/PI staining. RESULTS:The vector of RNA interference was successfully constructed and MAGEA3 expression was descreased significantly in MEL-ED1 cells. After the shRNA expression vector was transfected into the MEL-ED1 cells, the expression of MAGEA3 gene was inhibited significantly ( by 90% ). DNA fragmentation，electron microscopy and TUNEL assay showed classic apoptosis characters in the MEL-ED1 cells transfected with pSilencer-MAGEA3 plasmid with an apoptosis rate of 21.41% ±1.98%, significantly higher than those in the negative control group transfected with pSilencer-neo and in the non-transfected group (both P<0.01). CONCLUSION:The specific small hairpin RNA targeting MAGEA3 mRNA can inhibit the expression of MAGEA3 and cause apoptosis of hepatocellular carcinoma cells , which suggests inhibitory effect of MAGEA3 on apoptosis in cancer and provides an experimental basis for treating human tumors with RNAi.     

“中国园艺学会热带南亚热带果树分会成立大会暨首届学术研讨会”会讯

“中国园艺学会热带南亚热带果树分会”是由广东省农业科学院果树研究所、福建省农业科学院果树研究所、仲恺农业技术学院园艺系、中国热带农业科学院南亚热带作物研究所等单位联合申请,并经中国园艺学会第九届六次常务理事会扩大会议讨论同意成立的。经筹委会讨论决定,将于200