ABSTRACT
OBJECTIVE: Gene therapy is a frontier in modern medicine. In the present study, we explored a new technique for the effective treatment of multidrug-resistant (MDR) breast cancer by combining fully the advantages of multidisciplinary fields, including image-guided minimally invasive interventional oncology, radiofrequency technology, and direct intratumoral gene therapy. RESULTS: Combination treatment with PHSP-TK plus RFH resulted in significantly higher TK gene transfection/expression, as well as a lower cell proliferation rate and a higher cell apoptosis index, than those of control groups. In vivo validation experiments with MRI confirmed that combination therapy resulted in a significant reduction of relative tumor volume compared with those of control animals, which was supported by the results of histologic and apoptosis analyses. MATERIALS AND METHODS: The heat shock protein promoter (PHSP) was used to precisely control the overexpression of thymidine kinase (TK) (PHSP-TK). Serial in vitro experiments were performed to confirm whether radiofrequency hyperthermia (RFH) could enhance PHSP-TK transfection and expression in a MDR breast cancer cell line (MCF7/Adr). Serial in vivo experiments were then carried out to validate the feasibility of the new technique, termed interventional RFH-enhanced direct intratumoral PHSP-TK gene therapy. The therapeutic effect of combination therapy was evaluated by MRI and confirmed by subsequent laboratory correlation. CONCLUSIONS: This study has established "proof-of-principle" of a new technique, interventional RFH-enhanced local gene therapy for MDR breast cancer, which may open new avenues for the effective management of MDR breast cancers via the simultaneous integration of interventional oncology, RF technology, and direct intratumoral gene therapy.
Subject(s)
Breast Neoplasms , Genetic Therapy/methods , Hyperthermia, Induced/methods , Thymidine Kinase/genetics , Transfection/methods , Animals , Drug Resistance, Multiple , Drug Resistance, Neoplasm , Female , Genes, Transgenic, Suicide , Heat-Shock Proteins/genetics , Humans , MCF-7 Cells , Mice , Mice, Inbred BALB C , Promoter Regions, Genetic , Thymidine Kinase/administration & dosage , Thymidine Kinase/biosynthesis , Xenograft Model Antitumor AssaysABSTRACT
PURPOSE: The effect of the combination therapy of curcumin and the herpes simplex virus thymidine kinase (HSVtk) gene using R7L10 as a carrier was evaluated in a glioblastoma animal model. METHODS: Curcumin was loaded into the cores of R7L10 peptide micelles using an oil-in-water emulsion/solvent evaporation method to generate curcumin loaded R7L10 micelles (R7L10-Cur), which were used as a carrier to deliver the HSVtk gene. The plasmid DNA (pDNA)/R7L10-Cur complex was confirmed by gel retardation, heparin competition, and dynamic light scattering analyses. Transfection efficiency and cytotoxicity were measured using luciferase, MTT, and TUNEL assays. Intracellular delivery of curcumin was determined by fluorescence and absorbance. In the glioblastoma animal model, the effects of the intratumoral delivery of curcumin and the HSVtk gene were evaluated according to tumor size, immunohistochemistry, and TUNEL assays. RESULTS: R7L10-Cur delivered pDNA into the cells more efficiently than PLL and R7L10. In addition, R7L10-Cur delivered curcumin into the cells more efficiently than curcumin alone. The pHSVtk/R7L10-Cur complex induced cell death efficiently both in vitro and in vivo. Likewise, the combination of curcumin and the HSVtk gene using the pHSVtk/R7L10-Cur complex reduced tumor size more efficiently than the pHSVtk/PEI and pHSVtk/R7L10 complexes in a glioblastoma animal model. CONCLUSION: R7L10 is an efficient carrier for delivery of curcumin and the HSVtk gene, which may be a useful combination therapy for glioblastoma.
Subject(s)
Curcumin/administration & dosage , Gene Transfer Techniques , Glioblastoma/genetics , Micelles , Peptides/administration & dosage , Thymidine Kinase/administration & dosage , Animals , Cell Line, Tumor , Cell Survival/drug effects , Cell Survival/physiology , Combined Modality Therapy/methods , Curcumin/metabolism , Glioblastoma/metabolism , Glioblastoma/therapy , HEK293 Cells , Humans , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Peptides/genetics , Rats , Thymidine Kinase/genetics , Xenograft Model Antitumor Assays/methodsABSTRACT
Controlled release of a water-soluble low-molecular-weight drug from silicone and its usefulness as a local therapeutic drug were studied. For application to ganciclovir/helpes simplex virus thymidine kinase (GCV/HSV-tk) suicide gene therapy for brain tumor, two kinds of GCV-containing silicone formulations were prepared for evaluation. In vitro, GCV release from matrix-type formulation consisting of a single matrix was characterized by Fickian diffusion, while covered-rod-type formulation, in which the side surface of the outer layer was covered with 100% silicone, exhibited a near-zero-order release pattern. In an in vivo study using a rat 9L glioblastoma model, administration of GCV-silicone formulation into brain tumor yielded sustained intracerebral GCV concentration for 4 days after administration, with excellent antitumor effect equal to or better than that of daily intraperitoneal administration of aqueous solution of GCV, at a dose less than 1/100 of the total dose of solution for intraperitoneal administration. Furthermore, GCV was undetectable in blood, suggesting that decrease in systemic adverse reactions can be expected with intracerebral administration of GCV-silicone formulation.