lipofectamine and Colonic-Neoplasms

Bcl-2-associated athanogene 1 (Bag-1) is a positive regulator of Bcl-2 which is an anti-apoptotic gene. Bag-1 was very slightly expressed in normal tissues, but often highly expressed in many tumor tissues, particularly in colon cancer, which can promote metastasis, poor prognosis and anti-apoptotic function of colon cancer. We prepared and evaluated magnetic gold nanoparticle/Bag-1 siRNA recombinant plasmid complex, a gene therapy system, which can transfect cells efficiently, for both therapeutic effect and safety in vitro mainly by electrophoretic mobility shift assays, flow cytometric analyses, cell viability assays, western blot analyses and RT-PCR (real-time) assays. Magnetic gold nanoparticle/Bag-1 siRNA recombinant plasmid complex was successfully transfected into LoVo colon cancer cells and the exogenous gene was expressed in the cells. Flow cytometric results showed apoptosis rate was significantly increased. In MTT assays, magnetic gold nanoparticles revealed lower cytotoxicity than Lipofectamine 2000 transfection reagents (P<0.05). Both in western blot analyses and RT-PCR assays, magnetic gold nanoparticle/Bag-1 siRNA recombinant plasmid complex transfected cells demonstrated expression of Bag-1 mRNA (P<0.05) and protein (P<0.05) was decreased. In further study, c-myc and β-catenin which are main molecules of Wnt/β‑catenin pathway were decreased when Bag-1 were silenced in nanoparticle plasmid complex transfected LoVo cells. These results suggest that magnetic gold nanoparticle mediated siRNA silencing Bag-1 is an effective gene therapy method for colon cancer.

Topics: Adenocarcinoma; Apoptosis; Cell Line, Tumor; Colonic Neoplasms; DNA-Binding Proteins; Down-Regulation; Drug Screening Assays, Antitumor; Flow Cytometry; Genetic Vectors; Gold Colloid; Humans; Lipids; Magnets; Nanoparticles; Neoplasm Proteins; Particle Size; Plasmids; RNA Interference; RNA, Messenger; RNA, Neoplasm; RNA, Small Interfering; Transcription Factors; Transfection

To study the effect of synthesized ST6Gal I specific siRNA on the adhesion and invasiveness of human colon carcinoma cell line SW480 with over expression of ST6Gal I.. A double strand small interference RNA (siRNA) targeting ST6Gal I was designed and synthesized, and then transfected into SW480 cells by lipofectmine 2000. SW480 cells were cultured and divided into 4 groups: blank control group, liposome control group, non-specific siRNA group and ST6Gal I siRNA group. The expression of ST6Gal I mRNA was examined by RT-PCR and the amount of alpha-2, 6-sialylation on the SW480 cell surface was detected by flow cytometry. The adhesion and invasion of SW480 cells to extracellular matrix (ECM) were analyzed by using CytoMatrix kit and cell invasion assay kit, respectively.. After SW480 cells were transfected for 48 hours, the expression of ST6Gal I mRNA in ST6Gal I siRNA group was significantly decreased compared with that in the blank control group, liposome control group, and non-specific siRNA group (P<0.05). After SW480 cells were transfected for 72 hours, the amount of alpha-2, 6-sialylation on cell surface, the adhesion and invasion of the cells in ST6Gal I siRNA group were markedly lower than those in the other 3 groups (P<0.05).. The chemically synthesized specific siRNA targeting ST6Gal I can effectively inhibit the expression of ST6Gal I and reduce cell adhesion and invasion to ECM in SW480 cells. Our research is important for further study of anti-tumor treatment with RNA interference.

Topics: beta-D-Galactoside alpha 2-6-Sialyltransferase; Cell Adhesion; Cell Line, Tumor; Colonic Neoplasms; Flow Cytometry; Gene Silencing; Humans; Lipids; Neoplasm Invasiveness; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; RNA, Small Interfering; Sialyltransferases; Transfection

To explore the effects of human FRNK gene on E-cadherin/beta-catenin complex in colon cancer cell line Colo320WT cells stimulated with extrinsic gastrinl7.. AdEasy system was used to construct pAdhFRNK expressing human FRNK gene by recombination in E. coli. BJ5283. pCR3.1/GR plasmid expressing gastrin receptor CCK-2 was transfected into colon cancer cell line Colo320 cells by Lipofectamine 2000 and expressing stably CCK-2R clones were screened by G418 (500 pg/ml). The expression levels of gastrin receptor in Colo320 cells and the transfected Colo320WT cells were assayed by RT-PCR. Colo320WT cells were treated by 10(-8) mol/L gastrinl7 for 12 h; and after Colo320WT cells were infected by pAdhFRNK (MOI: 100) for 2 d the cells were treated by gastrin17 for 12 h again. The expression levels of E-cadherin and beta-catenin in TX-100 soluble fraction and TX-100 insoluble fraction of Colo320WT cells were assayed by co-immunoprecipation and Western blot. E-cadherin and beta-catenin's distribution in Colo320WT cells were detected by immunocytochemistry.. When 10(-8) mol/L gastrin17 stimulated Colo320WT cells for 12 h, the expression levels of E-cadherin and beta-catenin in TX-100-soluble fraction decreased apparently, while the expression levels of E-cadherin and beta-catenin in TX-100-insoluble fraction increased markedly. When pAdhFRNK infected Colo320WT cells for 2 d and 10(-8) mol/L gastrin17 treated the cells for 12 h, the expression levels of E-cadherin and beta-catenin in TX-100-soluble fraction increased apparently again, and the expression levels of E-cadherin and beta-catenin in TX-100-insolutble fraction decreased markedly. Immunocytochemistry showed that the distribution of E-cadherin and beta-catenin was translocated from plasma membrane into cytoplasm and nucleus in the cells stimulated with gastrinl7, and after the cells were infected with pAdhFRNK and stimulated by gastrinl7 again. beta-catenin was mainly observed in cytoplasm and little nuclear immunoreactivity.. An adenovirus vector pAdhFRNK can inhibit abnormal distribution of E-cadherin and beta-catenin in the gastrin17-stimulated cells. The mechanism is probably that hFRNK can disphosphorylate phosphorylated FAK and block FAK pathway.

Topics: Adenoviridae; beta Catenin; Blotting, Western; Cadherins; Cell Line, Tumor; Cell Membrane; Cell Nucleus; Colonic Neoplasms; Cytoplasm; Gastrins; Genetic Vectors; Humans; Immunohistochemistry; Immunoprecipitation; Lipids; Protein Binding; Protein Transport; Protein-Tyrosine Kinases; Receptor, Cholecystokinin B; Transfection