title: Combined modality doxorubicin-based chemotherapy and chitosan-mediated p53 gene therapy using double-walled microspheres for treatment of human hepatocellular carcinoma.
abstract: The therapeutic efficiency of combined chemotherapy and gene therapy on human hepatocellular carcinoma HepG2 cells was investigated using double-walled microspheres that consisted of a poly(D,L-lactic-co-glycolic acid) (PLGA) core surrounded by a poly(L-lactic acid) (PLLA) shell layer and fabricated via the precision particle fabrication (PPF) technique. Here, double-walled microspheres were used to deliver doxorubicin (Dox) and/or chitosan-DNA nanoparticles containing the gene encoding the p53 tumor suppressor protein (chi-p53), loaded in the core and shell phases, respectively. Preliminary studies on chi-DNA nanoparticles were performed to optimize gene transfer to HepG2 cells. The transfection efficiency of chi-DNA nanoparticles was optimal at an N/P ratio of 7. In comparison to the 25-kDa branched polyethylenimine (PEI), chitosan showed no inherent toxicity towards the cells. Next, the therapeutic efficiencies of Dox and/or chi-p53 in microsphere formulations were compared to free drug(s) and evaluated in terms of growth inhibition, and cellular expression of tumor suppressor p53 and apoptotic caspase 3 proteins. Overall, the combined Dox and chi-p53 treatment exhibited enhanced cytotoxicity as compared to either Dox or chi-p53 treatments alone. Moreover, the antiproliferative effect was more substantial when cells were treated with microspheres than those treated with free drugs. High p53 expression was maintained during a five-day period, and was largely due to the controlled and sustained release of the microspheres. Moreover, increased activation of caspase 3 was observed, and was likely to have been facilitated by high levels of p53 expression. Overall, double-walled microspheres present a promising dual anticancer delivery system for combined chemotherapy and gene therapy.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576, Singapore.
authors.forename: Qingxing
authors.initials: Q
authors.lastname: Xu
authors.forename: Jiayu
authors.initials: J
authors.lastname: Leong
authors.forename: Qi Yi
authors.initials: QY
authors.lastname: Chua
authors.forename: Yu Tse
authors.initials: YT
authors.lastname: Chi
authors.forename: Pierce Kah-Hoe
authors.initials: PK
authors.lastname: Chow
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Pack
authors.forename: Chi-Hwa
authors.initials: CH
authors.lastname: Wang
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry*; D003131:Combined Modality Therapy; D004247:DNA / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology / Q000627:therapeutic use*; D005455:Fluorescent Antibody Technique; D015316:Genetic Therapy; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000473:pathology; D008156:Luciferases / Q000378:metabolism; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000627:therapeutic use
chemical_list: D016159:Tumor Suppressor Protein p53; D004317:Doxorubicin; D004247:DNA; D048271:Chitosan; D008156:Luciferases; D053148:Caspase 3