title: Electroporation of synthetic oligodeoxynucleotides: a novel technique for ex vivo bone marrow purging.
abstract: Recent data suggest that tumor cells contaminating reinfused bone marrow may contribute to relapse in patients undergoing autologous bone marrow transplantation. Purging strategies that are able to remove these contaminating tumor cells need to be developed. This study describes how electroporation (EP) can be used to improve intracellular delivery of synthetic antisense oligodeoxynucleotides (ODNs), thereby enhancing their ability to suppress a target protein. Antisense ODNs that were introduced into cells by EP led to immediate suppression of targeted c-myc protein; this was associated with rapid cell death in the diffuse histiocytic lymphoma, U937; Burkitt's lymphoma, ST486; breast carcinoma, MCF-7; and Ewing's sarcoma, CHP-100, cell lines. Electroporation was found to have little or no detrimental effect on cells responsible for murine hematopoietic long-term reconstitution as determined from in vivo competitive repopulation studies. Using human c-myc-directed antisense ODNs as a model for the application of this approach to bone marrow purging, selective killing of human lymphoma U937 cells relative to normal human bone marrow cells was shown in cell mixing studies. In vivo studies were performed in which a survival advantage was shown for athymic mice that were inoculated with antisense-treated U937 cells as opposed to control cells. These studies suggest that EP of bone marrow may be of use in enhancing intracellular delivery of a variety of molecular/pharmaceutical agents. Taken together, these data suggest that the use of electroporation to enhance delivery of antisense ODNs is a promising new approach towards ex vivo bone marrow purging.
authors.affiliation: Clinical Pharmacology Branchel, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: R
authors.initials: R
authors.lastname: Bergan
authors.forename: F
authors.initials: F
authors.lastname: Hakim
authors.forename: G N
authors.initials: GN
authors.lastname: Schwartz
authors.forename: E
authors.initials: E
authors.lastname: Kyle
authors.forename: R
authors.initials: R
authors.lastname: Cepada
authors.forename: J M
authors.initials: JM
authors.lastname: Szabo
authors.forename: D
authors.initials: D
authors.lastname: Fowler
authors.forename: R
authors.initials: R
authors.lastname: Gress
authors.forename: L
authors.initials: L
authors.lastname: Neckers
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology; D000818:Animals; D017209:Apoptosis; D001853:Bone Marrow / Q000473:pathology*; D016465:Bone Marrow Purging / Q000379:methods*; D001859:Bone Neoplasms / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology; D002051:Burkitt Lymphoma / Q000473:pathology; D003114:Colony-Forming Units Assay; D018274:Electroporation; D005260:Female; D006410:Hematopoiesis / Q000187:drug effects; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000187:drug effects*; D016376:Oligonucleotides, Antisense / Q000138:chemical synthesis / Q000494:pharmacology*; D016271:Proto-Oncogene Proteins c-myc / Q000037:antagonists & inhibitors* / Q000235:genetics; D012512:Sarcoma, Ewing / Q000473:pathology; D014407:Tumor Cells, Cultured
chemical_list: D016376:Oligonucleotides, Antisense; D016271:Proto-Oncogene Proteins c-myc