RESUMO
Here we report on the application of cationic liposomes formed by new cationic lipids and the lipid-helper DOPE (dioleoylphosphatidylethanolamine) for the transfection of plasmid DNA and mRNA into dendritic cells (DCs) progenitors and immature DCs of bone-marrow origin in vitro and the use of these DCs to induce the suppression of B16 melanoma metastases in vivo. The cationic lipids contain one (X2, S1, S2 and S3) or two (2X3) cholesterol residues or long-chain hydrocarbon substituent (2D3) linked with spermine. Data show that liposomes 2X3-DOPE, 2D3-DOPE, X2-DOPE and S2-DOPE display high transfection efficiency in respect to DNA (30-47% of DC progenitors and up to 57% of immature DC were transfected) and RNA (up to 57% of cells were transfected). The studied lipids exhibited an efficiency of DNA and RNA delivery in DCs several times higher in comparison with Lipofectamine 2000. Observed ex vivo the higher transfection efficiencies of DCs with mRNAs encoding of a set of tumor-associated antigens provided by cationic liposomes 2X3-DOPE and 2X2-DOPE corresponded to a 3-5 fold suppression of metastasis number in a model of murine B16 melanoma in vivo. The injection into mice of these pulsed DCs resulted in a slight pro-inflammatory response which was balanced by the positive effect of the antitumor cytokine production induced by the DCs. The obtained data show that the novel spermine-based polycationic lipids can be applied in the preparation of antitumor DC-based vaccine.
Assuntos
Células da Medula Óssea/metabolismo , DNA/administração & dosagem , Células Dendríticas/metabolismo , Portadores de Fármacos/química , RNA Mensageiro/administração & dosagem , Células-Tronco/metabolismo , Animais , Células da Medula Óssea/imunologia , Linhagem Celular Tumoral , Citocinas/sangue , DNA/genética , Células Dendríticas/imunologia , Proteínas de Fluorescência Verde/genética , Lipossomos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/secundário , Neoplasias Pulmonares/terapia , Masculino , Melanoma Experimental/genética , Melanoma Experimental/imunologia , Melanoma Experimental/secundário , Melanoma Experimental/terapia , Camundongos , Camundongos Endogâmicos C57BL , Estrutura Molecular , Transplante de Neoplasias , Fosfatidiletanolaminas/química , Plasmídeos , Poliaminas/química , Polieletrólitos , RNA Mensageiro/genética , Células-Tronco/imunologia , TransfecçãoRESUMO
BACKGROUND: One of the main obstacles for successful cancer polychemotherapy is multiple drug resistance phenotype (MDR) acquired by tumor cells. Currently, RNA interference represents a perspective strategy to overcome MDR via silencing the genes involved in development of this deleterious phenotype (genes of ABC transporters, antiapoptotic genes, etc.). METHODS: In this study, we used the siRNAs targeted to mdr1b, mdr1a, and bcl-2 mRNAs to reverse the MDR of tumors and increase tumor sensitivity to chemotherapeutics. The therapy consisting in ex vivo or in vivo application of mdr1b/1a siRNA followed by cyclophosphamide administration was studied in the mice bearing RLS40 lymphosarcoma, displaying high resistance to a wide range of cytostatics. RESULTS: Our data show that a single application of mdr1b/1a siRNA followed by treatment with conventionally used cytostatics results in more than threefold decrease in tumor size as compared with the control animals receiving only cytostatics. CONCLUSIONS: In perspective, mdr1b/1a siRNA may become a well-reasoned adjuvant tool in the therapy of MDR malignancies.
