Construction of folate-conjugated pRNA of bacteriophage phi29 DNA packaging motor for delivery of chimeric siRNA to nasopharyngeal carcinoma cells.
Nasopharyngeal carcinoma is a poorly differentiated upper respiratory tract cancer that highly expresses human folate receptors (hFR). Binding of folate to hFR triggers endocytosis. The folate was conjugated into adenosine 5'-monophosphate (AMP) by 1,6-hexanediamine linkages. After reverse HPLC to reach 93% purity, the folate-AMP, which can only be used for transcription initiation but not for chain extension, was incorporated into the 5'-end of bacteriophage phi29 motor pRNA. A 16:1 ratio of folate-AMP to ATP in transcription resulted in more than 60% of the pRNA containing folate. A pRNA with a 5'-overhang is needed to enhance the accessibility of the 5' folate for specific receptor binding. Utilizing the engineered left/right interlocking loops, polyvalent dimeric pRNA nanoparticles were constructed using RNA nanotechnology to carry folate, a detection marker, and siRNA targeting at an antiapoptosis factor. The chimeric pRNAs were processed into ds-siRNA by Dicer. Incubation of nasopharyngeal epidermal carcinoma (KB) cells with the dimer resulted in its entry into cancer cells, and the subsequent silencing of the target gene. Such a protein-free RNA nanoparticle with undetectable antigenicity has a potential for repeated long-term administration for nasopharyngeal carcinoma as the effectiveness and specificity were confirmed by ex vivo delivery in the animal trial.
Guo
S
S
Department of Pathobiology and Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
Huang
F
F
Guo
P
P
D000249:Adenosine Monophosphate / Q000235:genetics / Q000378:metabolism; D000818:Animals; D017103:Bacillus Phages / Q000235:genetics*; D002352:Carrier Proteins / Q000378:metabolism; D002478:Cells, Cultured; D002678:Chimera; D042003:DNA Packaging; D058973:Folate Receptors, GPI-Anchored; D005492:Folic Acid / Q000235:genetics*; D020868:Gene Silencing; D005818:Genetic Engineering; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D049329:Nanostructures; D009303:Nasopharyngeal Neoplasms / Q000628:therapy*; D009374:Neoplasms, Experimental / Q000378:metabolism / Q000628:therapy; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D011956:Receptors, Cell Surface / Q000378:metabolism
D002352:Carrier Proteins; D058973:Folate Receptors, GPI-Anchored; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; D000249:Adenosine Monophosphate; D005492:Folic Acid