as-1411 and Brain-Neoplasms

Topics: Animals; Antineoplastic Agents; Brain Neoplasms; Cell Line, Tumor; Docetaxel; Humans; Micelles; Transferrin

Radioresistance significantly decreases the efficacy of radiotherapy, which can ultimately lead to tumor recurrence and metastasis. As a novel type of nano-radiosensitizer, silver nanoparticles (AgNPs) have shown promising radiosensitizing properties in the radiotherapy of glioma, but their ability to efficiently enter and accumulate in tumor cells needs to be improved. In the current study, AS1411 and verapamil (VRP) conjugated bovine serum albumin (BSA) coated AgNPs (AgNPs@BSA-AS-VRP) were synthesized and characterized. Dark-field imaging and inductively coupled plasma mass spectrometry were applied to investigate the accumulation of AgNPs@BSA-AS and AgNPs@BSA-AS-VRP mixed in different ratios in U251 glioma cells. To assess the influences of 19:1 mixed AgNPs@BSA-AS and AgNPs@BSA-AS-VRP on the P-glycoprotein (P-gp) efflux activity, rhodamine 123 accumulation assay was carried out. Colony formation assay and tumor-bearing nude mice model were employed to examine the radiosensitizing potential of 19:1 mixed AgNPs@BSA-AS and AgNPs@BSA-AS-VRP. Thioredoxin Reductase (TrxR) Assay Kit was used to detect the TrxR activity in cells treated with different functionally modified AgNPs. Characterization results revealed that AgNPs@BSA-AS-VRP were successfully constructed. When AgNPs@BSA-AS and AgNPs@BSA-AS-VRP were mixed in a ratio of 19:1, the amount of intracellular nanoparticles increased greatly through AS1411-mediated active targeting and inhibition of P-gp activity. In vitro and in vivo experiments clearly showed that the radiosensitization efficacy of 19:1 mixed AgNPs@BSA-AS and AgNPs@BSA-AS-VRP was much stronger than that of AgNPs@BSA and AgNPs@BSA-AS. It was also found that 19:1 mixed AgNPs@BSA-AS and AgNPs@BSA-AS-VRP significantly inhibited intracellular TrxR activity. These results indicate that 19:1 mixed AgNPs@BSA-AS and AgNPs@BSA-AS-VRP can effectively accumulate in tumor cells and have great potential as high-efficiency nano-radiosensitizers in the radiotherapy of glioma.

Topics: Aptamers, Nucleotide; Brain Neoplasms; Cell Line, Tumor; Glioma; Humans; Metal Nanoparticles; Oligodeoxyribonucleotides; Radiation Tolerance; Radiation-Sensitizing Agents; Silver; Verapamil

Chemotherapy is still the main adjuvant strategy after surgery in glioblastoma therapy. As the main obstacles of chemotherapeutic drugs for glioblastoma treatment, the blood brain barrier (BBB) and non-specific delivery to non-tumor tissues greatly limit the accumulation of drugs into tumor tissues and simultaneously cause serious toxicity to nearby normal tissues which altogether compromised the chemotherapeutic effect. In the present study, we established an aptamer AS1411-functionalized poly (l-γ-glutamyl-glutamine)-paclitaxel (PGG-PTX) nanoconjugates drug delivery system (AS1411-PGG-PTX), providing an advantageous solution of combining the precisely active targeting and the optimized solubilization of paclitaxel. The receptor nucleolin, highly expressed in glioblastoma U87 MG cells as well as neo-vascular endothelial cells, mediated the binding and endocytosis of AS1411-PGG-PTX nanoconjugates, leading to significantly enhanced uptake of AS1411-PGG-PTX nanoconjugates by tumor cells and three-dimension tumor spheroids, and intensive pro-apoptosis effect of AS1411-PGG-PTX nanoconjugates. In vivo fluorescence imaging and tissue distribution further demonstrated the higher tumor distribution of AS1411-PGG-PTX as compared with PGG-PTX. As a result, the AS1411-PGG-PTX nanoconjugates presented the best anti-glioblastoma effect with prolonged median survival time and most tumor cell apoptosis in vivo as compared with other groups. In conclusion, the AS1411-PGG-PTX nanoconjugates exhibited a promising targeting delivery strategy for glioblastoma therapy.

Topics: Animals; Antineoplastic Agents, Phytogenic; Aptamers, Nucleotide; Brain; Brain Neoplasms; Cell Line, Tumor; Drug Delivery Systems; Glioblastoma; Human Umbilical Vein Endothelial Cells; Humans; Mice, Inbred BALB C; Mice, Nude; Nanoconjugates; Oligodeoxyribonucleotides; Paclitaxel; Proteins

AS1411 binds nucleolin (NCL) and is the first oligodeoxynucleotide aptamer to reach phase I and II clinical trials for the treatment of several cancers. However, the mechanisms by which AS1411 targets and kills glioma cells and tissues remain unclear. Here we report that AS1411 induces cell apoptosis and cycle arrest, and inhibits cell viability by up-regulation of p53 and down-regulation of Bcl-2 and Akt1 in human glioma cells. NCL was overexpressed in both nucleus and cytoplasm in human glioma U87, U251 and SHG44 cells compared to normal human astrocytes (NHA). AS1411 bound NCL and inhibited the proliferation of glioma cells but not NHA, which was accompanied with up-regulation of p53 and down-regulation of Bcl-2 and Akt1. Moreover, AS1411 treatment resulted in the G2/M cell cycle arrest in glioma cells, which was however abolished by overexpression of NCL. Further, AS1411 induced cell apoptosis, which was prevented by silencing of p53 and overexpression of Bcl-2. In addition, AS1411 inhibited the migration and invasion of glioma cells in an Akt1-dependent manner. Importantly, AS1411 inhibited the growth of glioma xenograft and prolonged the survival time of glioma tumor-bearing mice. These results revealed a promising treatment of glioma by oligodeoxynucleotide aptamer.

Topics: Animals; Antineoplastic Agents; Apoptosis; Aptamers, Nucleotide; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Female; G2 Phase Cell Cycle Checkpoints; Gene Expression Regulation, Neoplastic; Glioma; Humans; Male; Mice; Mice, SCID; Middle Aged; NF-kappa B; Nucleolin; Oligodeoxyribonucleotides; Phosphoproteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; RNA-Binding Proteins; Signal Transduction; Survival Analysis; Tumor Suppressor Protein p53; Xenograft Model Antitumor Assays

To evaluate the internalization and subcellular fate of AS1411 aptamer (for glioma targeting) and TGN peptide (for blood-brain barrier targeting)-modified nanoparticles (AsTNPs), which was important for optimizing targeted delivery systems and realizing the potential toxicity to cells.. Organelles were labelled with specific markers. Several uptake inhibitors were used to determine the endocytosis pathways. Transmission electron microscopy (TEM) was utilized to directly observe the endocytosis procedure and subcellular fate of AsTNPs.. Subcellular localization demonstrated that endosomes and mitochondria were involved in the uptake of AsTNPs by both C6 and bEnd.3 cells, however, lysosomes and Golgi apparatus were only involved in the internalization by C6 cells rather than bEnd.3 cells. Uptake mechanism study demonstrated the clathrin- and caveolae-mediated endocytosis were the main pathways in the uptake of AsTNPs by C6 and bEnd.3 cells. However, other pathways, including clathrin- and caveolae-independent endocytosis and macropinocytosis are also involved in the uptake by C6 cells and not by bEnd.3 cells. TEM directly demonstrated the involvement of these pathways. Particles could be found mostly in endosomes.. Compared to unmodified nanoparticles, AsTNPs displayed different internalization pathways involved in several cell organelles.

Topics: Animals; Aptamers, Nucleotide; Blood-Brain Barrier; Brain Neoplasms; Cell Line, Tumor; Drug Carriers; Endocytosis; Endothelial Cells; Glioma; Mice; Microscopy, Electron, Transmission; Nanoparticles; Oligodeoxyribonucleotides; Particle Size; Peptides; Subcellular Fractions; Surface Properties

The three oncogenes, ErbB receptors, Ras proteins and nucleolin may contribute to malignant transformation. Previously, we demonstrated that nucleolin could bind both Ras protein and ErbB receptors. We also showed that the crosstalk between the three proteins facilitates anchorage independent growth and tumor growth in nude mice, and that inhibition of this interaction in prostate and colon cancer cells reduces tumorigenicity. In the present study, we show that treatment with Ras and nucleolin inhibitors reduces the oncogenic effect induced by ErbB1 receptor in U87-MG cells. This combined treatment enhances cell death, reduces cell proliferation and cell migration. Moreover, we demonstrate a pivotal role of nucleolin in ErbB1 activation by its ligand. Nucleolin inhibitor prevents EGF-induced receptor activation and its downstream signaling followed by reduced proliferation. Furthermore, inhibition of Ras by Salirasib (FTS), mainly reduces cell viability and motility. The combined treatment, which targets both Ras and nucleolin, additively reduces tumorigenicity both in vitro and in vivo. These results suggest that targeting both nucleolin and Ras may represent an additional opportunity for inhibiting cancers, including glioblastoma, that are driven by these oncogenes.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Aptamers, Nucleotide; Brain Neoplasms; Cell Death; Cell Line, Tumor; Cell Movement; Cell Proliferation; ErbB Receptors; Farnesol; Glioblastoma; Humans; Mice, Nude; Nucleolin; Oligodeoxyribonucleotides; Phosphoproteins; Phosphorylation; ras Proteins; Receptor Cross-Talk; RNA-Binding Proteins; Salicylates; Signal Transduction; Time Factors; Tumor Burden