Temozolomide (TMZ) is a promising chemotherapeutic agent for treating glioblastomas. However, resistance develops quickly and with a high frequency. Efforts to overcome chemoresistance are, therefore, critically needed. In present study, a poly(amidoamine; PAMAM) dendrimer was used as a vector to deliver microRNA-21 inhibitor (miR-21i) into U87 cells and the chemosensitivity of the combination effect of miR-21i and TMZ for glioma therapy was investigated. Flow cytometry analysis showed the uptake efficiency of microRNA-21 inhibitor after complexation with PAMAM. Real-time PCR and in situ hybridization indicated that, compared with TMZ or miR-21i treated cells, cells simultaneously treated with miR-21i and TMZ showed a remarkable decrease in the microRNA-21 (miR-21) level. The transfection of miR-21i enhanced the chemosensitivity by significantly decreasing the IC50 value of TMZ to glioma cells. Knockdown of miR-21 promoted the cells' apoptosis, and at the same time, inhibited cell invasion. In conclusion, the combination treatment of glioma cells with TMZ and miR-21i could yield a synergistic effect in inhibition of human glioma cell line. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

In the current study, we evaluated the efficiency of folate-polyamidoamine dendrimers conjugates (FA-PAMAM) for the in situ delivery of therapeutic antisense oligonucleotides (ASODN) that could inhibit the growth of C6 glioma cells. Folic acid was coupled to the surface amino groups of G5-PAMAM dendrimer (G5D) through a 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide bond, and ASODNs corresponding to rat epidermal growth factor receptor (EGFR) were then complexed with FA-PAMAM. At an ASODN to PAMAM ratio of 16:1, agarose electrophoresis indicated that antisense oligonucleotides were completely complexed with PAMAM or FA-PAMAM. The ASODN transfection rates mediated by FA-PAMAM and PAMAM were superior to oligofectamine, resulting in greater suppression of EGFR expression and glioma cell growth. Stereotactic injection of EGFR ASODN:FA-PAMAM complexes into established rat C6 intracranial gliomas resulted in greater suppression of tumor growth and longer survival time of tumor-bearing rats compared with PAMAM and oligofectamine-mediated EGFR-ASODN therapy. The current study demonstrates the suitability of folate-PAMAM dendrimer conjugates for efficient EGFR ASODN delivery into glioma cells, wherein they release the ASODN from the FA-PAMAM to knock down EGFR expression in C6 glioma cells, both in vitro and in vivo. FA-PAMAM may thus represent a novel delivery system for short oligonucleotides in glioma-targeted therapy. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010

The major aim of this work was to prepare injectable paclitaxel-loaded poly(D,L-lactide) microspheres for the inhibition of brain glioma. Paclitaxel-loaded PLA microspheres were prepared by spray drying method employing ethyl acetate as solvent. And the microspheres were characterized by scanning electron microscopy (SEM) for the morphology and differential scanning calorimetry for thermal analysis. The encapsulation efficiency (EE) and in vitro release profiles of paclitaxel-loaded microspheres were determined by using ultraviolet spectrophotometer. The results showed that the microspheres possess a narrow size distribution with the average diameter of 4.6 μm. The surface of the microspheres was smooth, and the paclitaxel dispersed in microspheres in amorphous state. The solvent residue was 0.03%, and the EE reaches ∼ 90%. The microspheres exhibited a sustained release behavior, and the release period last for at least three months, depending on the EE of the microspheres. The γ irradiation sterilization had little effect on the EE and drug release in vitro. Compared with the commercial formulation, the sustained release microsphere showed a stronger inhibition on the tumor cells, suggesting the potential application of long-term delivery of paclitaxel-loaded PLA microspheres in clinic tumor therapy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Carmustine-loaded poly(lactic acid) (PLA) nanoparticles were prepared with a spontaneous emulsification-solvent diffusion method by using Pluroinc F68 as emulsifying agent, and the influence of micellar behavior of surfactant in aqueous solution on the sizes of the nanoparticles was studied. The results revealed that F68 dissolved as unimers in water or sodium acetate-acetic acid buffer with pH value ranged from 5.0 to 5.5, resulting in larger PLA particles (226 nm) or clumps. In acidic media with pH of 4.0 and 4.5, however, F68 aggregated into micelles over the concentration of 3.7 and 4.8 mg/mL, as a result, ultrasmall nanoparticles with a size 50 and 80 nm could be obtained, respectively. The change in size had less effect on the drug content and entrapment efficiency, and the nanoparticles strongly enhanced the cytotoxic effect of the loaded drug in vitro, and this effect being more relevant for prolonged incubation times. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008