as-1411 and Stomach-Neoplasms

Chemotherapy, a conventional method assessed in recent oncology studies, poses numerous problems in the clinical environment. To overcome the problems inherent in chemotherapy, an intelligent drug delivery system has come to the forefront of cancer therapeutics. In this study, we designed a dendrimer-based pharmaceutical system together with a single-stranded AS1411 aptamer (APT

Topics: Animals; Aptamers, Nucleotide; Cell Line, Tumor; Dendrimers; Drug Carriers; Drug Delivery Systems; HEK293 Cells; Humans; Male; Mice; Mice, Inbred BALB C; Nanoparticles; Oligodeoxyribonucleotides; Stomach Neoplasms; Treatment Outcome; Xenograft Model Antitumor Assays

In this project, synergistic cancer cell death was achieved by a targeted delivery system comprising Bcl-xL-specific shRNA and a very low DOX content, which simultaneously activated an intrinsic apoptotic pathway. A modified branched polyethylenimine (PEI 10kDa) was grafted through polyethylene glycol (PEG) linker to carboxylated single-walled carbon nanotubes (SWCNT) to serve as a vehicle for shRNA delivery. The SWNT-PEG-PEI conjugate was covalently attached to AS1411 aptamer as the nucleolin ligand to target the co-delivery system to the tumor cells overexpressing nucleolin receptors on their surface. The final vehicle was eventually obtained after intercalation of DOX with pBcl-xL shRNA-SWCNT-PEG-10-10%PEI-Apt. Cell viability assay, GFP expression and transfection experiment against L929 (-nucleolin) and AGS (+nucleolin) cells illustrated that the tested targeted delivery system inhibited the growth of nucleolin-abundant gastric cancer cells with strong cell selectivity. Subsequently, we illustrated that the combination treatment of the selected shRNAs and DOX had excellent tumoricidal efficacy as verified by MTT assay. Furthermore, very low concentration of DOX, approximately 58-fold lower than its IC50 concentration, was used which could mitigate toxic side effects of DOX. Overall, our work revealed that combination of shRNA-mediated gene-silencing strategy with chemotherapeutic agents constitutes a valuable and safe approach for antitumor activity.

Topics: Antineoplastic Agents; Aptamers, Nucleotide; Cell Line, Tumor; Cell Survival; Doxorubicin; Drug Delivery Systems; Gene Silencing; Gene Transfer Techniques; Humans; Inhibitory Concentration 50; Nanotubes, Carbon; Nucleolin; Oligodeoxyribonucleotides; Phosphoproteins; Polyethylene Glycols; Polyethyleneimine; RNA-Binding Proteins; RNA, Small Interfering; Stomach Neoplasms; Transfection

Nucleolin is an abundant non-ribosomal protein found in nucleolus and a major component of silver-stained nucleolar organizer region (AgNOR), a histopathological marker of cancer which is highly elevated in cancer cells. We recently reported that nucleolin on the cell surface of mouse gastric cancer cells acts as a receptor for tumor necrosis factor-alpha-inducing protein (Tipalpha), a new carcinogenic factor of Helicobacter pylori. In this study, we first examined the localization of nucleolin on cell surface of five gastric cancer cell lines by cell fractionation and flow cytometry: We found that large amounts of nucleolin were present on surface of MKN-45, KATOIII, MKN-74, and AGS cells, with smaller amounts on surface of MKN-1 cells. The membrane fraction of normal epithelial cells of mouse glandular stomach did not contain much nucleolin, suggesting that translocation of nucleolin to the cell surface occurs during carcinogenesis, making for easier binding with Tipalpha. AS1411, a nucleolin targeted DNA aptamer, inhibited growth of gastric cancer cell lines in this order of potency: MKN-45>KATOIII>AGS>MKN-74=MKN-1, associated with induction of S-phase cell cycle arrest. Fluorescein isothiocyanate (FITC)-AS1411 was more rapidly incorporated into MKN-45 and AGS than into MKN-1 cells, based on varying amounts of cell surface nucleolin. We think that AS1411 first binds to nucleolin on the cell surface and that the binding complex is then incorporated into the cells. All results indicate that nucleolin on the cell surface is a new and promising therapeutic target for treatment of gastric cancer.

Topics: Animals; Antineoplastic Agents; Aptamers, Nucleotide; Bacterial Proteins; Biological Transport; Cell Line, Tumor; Cell Membrane; Epithelial Cells; Fluorescein; Gastric Mucosa; Helicobacter pylori; Humans; Isothiocyanates; Mice; Mice, Inbred BALB C; Nucleolin; Oligodeoxyribonucleotides; Phosphoproteins; Receptors, Cell Surface; RNA-Binding Proteins; S Phase; Stomach Neoplasms