Folate-Conjugated PAMAM Dendrimer For The Targeting Gene Tranfection To Glioma And Brain Tumor Inbition In Vitro And In Vivo

FA-PAMAM was synthesized for the targeting gene delivery to glioma. The complexing of ODN to PAMAM and FA-PAMAM was investigated via garose gel electrophoretogram, the result showed that the N/P ratio of positive electricity complexes should above 16:1. The mophologies of FA-PAMAM/ODN and PAMAM/ODN were observed by TEM, and complexes with N/P ratio of 16:1 and 32:1 were spheral in shape, and the size was between 50nm to 80 nm.To investigate the gene transfection mediated by PAMAM on human U251 giloma cell line, dynamic fluorescent microscope observation,RT-PCR and cell immunofluorescence experiments were carried out. The results demonstrated that EGFR mRNA expression and EGFR protein expression were knocked down remarkably in glioma cell after ASODN transfection. MTT analysis revealed that PAMAM exhibited a week cell-toxicity comparabled with oligofectamine, and the cell-toxicity increased with the N/P ratio of PAMAM to ASODN.The gene transfection and tumor inhibition were investigated in vitro and in vivo using C6 glioma cell line as cell model. Flow cytometry measurement domonstrated a high transfection ratio (97.36%) of FA-PAMAM. And both the cell experiments in vitro and in vivo showed the lowering cell proliferation activity, attenuated cell invasive ability and induced cell apoptosis of glioma cell after the ASODN delivery mediated by FA-PAMAM, PAMAM and oligofectamine. However, FA-PAMAM/ASODN showed a significent tumor inbition than PAMAM/ASODN and oligofectamine/ASODN, suggesting the tumor targeting ability of FA-PAMAM as gene carrier.The biodistributions of ODN after injection FA-PAMAM/ODN, PAMAM/ODN, oligofectamine/ODN and naked ODN intravenously were investigated using floursecence spectrophotometer and fluorescent microscope observation, the ODN deliveried by FA-PAMAM predominantly distributed on tumor compared with the biodistribution of other gene delivery system, proving the tumor targeting ability in vivo of PAMAM mediated by FA functional factor.