title: Specific delivery of therapeutic RNAs to cancer cells via the dimerization mechanism of phi29 motor pRNA.
abstract: The application of small RNA in therapy has been hindered by the lack of an efficient and safe delivery system to target specific cells. Packaging RNA (pRNA), part of the DNA-packaging motor of bacteriophage phi29(Phi29), was manipulated by RNA nanotechnology to make chimeric RNAs that form dimers via interlocking right- and left-hand loops. Fusing pRNA with receptor-binding RNA aptamer, folate, small interfering RNA (siRNA), ribozyme, or another chemical group did not disturb dimer formation or interfere with the function of the inserted moieties. Incubation of cancer cells with the pRNA dimer, one subunit of which harbored the receptor-binding moiety and the other harboring the gene-silencing molecule, resulted in their binding and entry into the cells, and subsequent silencing of anti/proapoptotic genes. The chimeric pRNA complex was found to be processed into functional double-stranded siRNA by Dicer (RNA-specific endonuclease). Animal trials confirmed the suppression of tumorigenicity of cancer cells by ex vivo delivery. It has been reported [Shu, D., Moll, W.-D., Deng, Z., Mao, C., and Guo, P. (2004). Nano Lett. 4:1717-1724] that RNA can be used as a building block for bottom-up assembly in nanotechnology. The assembly of protein-free 25-nm RNA nanoparticles reported here will allow for repeated long-term administration and avoid the problems of short retention time of small molecules and the difficulties in the delivery of particles larger than 100 nm.
authors.affiliation: Department of Pathobiology and Purdue Cancer Research Center, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Songchuan
authors.initials: S
authors.lastname: Guo
authors.forename: Nuska
authors.initials: N
authors.lastname: Tschammer
authors.forename: Sulma
authors.initials: S
authors.lastname: Mohammed
authors.forename: Peixuan
authors.initials: P
authors.lastname: Guo
mesh_terms: D000818:Animals; D017209:Apoptosis; D017103:Bacillus Phages / Q000235:genetics*; D045744:Cell Line, Tumor; D019281:Dimerization; D016503:Drug Delivery Systems; D015316:Genetic Therapy; D051034:Inhibitor of Apoptosis Proteins; D051379:Mice; D008819:Mice, Nude; D008869:Microtubule-Associated Proteins / Q000187:drug effects; D009363:Neoplasm Proteins / Q000187:drug effects; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D034741:RNA, Small Interfering / Q000378:metabolism / Q000627:therapeutic use*; D012367:RNA, Viral / Q000235:genetics; D000077022:Survivin; D014162:Transfection
chemical_list: C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering; D012367:RNA, Viral; D000077022:Survivin