title: Tumor-targeted inhibition by a novel strategy - mimoretrovirus expressing siRNA targeting the Pokemon gene.
abstract: Pokemon gene has crucial but versatile functions in cell differentiation, proliferation and tumorigenesis. It is a master regulator of the ARF-HDM2-p53 and Rb-E2F pathways. The facts that the expression of Pokemon is essential for tumor formation and many kinds of tumors over-express the Pokemon gene make it an attractive target for therapeutic intervention for cancer treatment. In this study, we used an RNAi strategy to silence the Pokemon gene in a cervical cancer model. To address the issues involving tumor specific delivery and durable expression of siRNA, we applied the Arg-Gly-Asp (RGD) peptide ligand and polylysine (K(18)) fusion peptide to encapsulate a recombinant retrovirus plasmid expressing a siRNA targeting the Pokemon gene and produced the 'mimoretrovirus'. At charge ratio 2.0 of fusion peptide/plasmid, the mimoretrovirus formed stable and homogenous nanoparticles, and provided complete DNase I protection and complete gel retardation. This nanoparticle inhibited SiHa cell proliferation and invasion, while it promoted SiHa cell apoptosis. The binding of the nanoparticle to SiHa cells was mediated via the RGD-integrin α(v)β(3) interaction, as evidenced by the finding that unconjugated RGD peptide inhibited this binding significantly. This tumor-targeting mimoretrovirus exhibited excellent anti-tumor capacity in vivo in a nude mouse model. Moreover, the mimoretrovirus inhibited tumor growth with a much higher efficiency than recombinant retrovirus expressing siRNA or the K(18)/P4 nanoparticle lacking the RGD peptide. Results suggest that the RNAi/RGD-based mimoretrovirus developed in this study represents a novel anti-tumor strategy that may be applicable to most research involving cancer therapy and, thus, has promising potential as a cervical cancer treatment.
authors.affiliation: Department of Immunology, Third Military Medical University, Chongqing 400038, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Tian
authors.forename: Huaizhi
authors.initials: H
authors.lastname: Wang
authors.forename: Zhengcai
authors.initials: Z
authors.lastname: Jia
authors.forename: Jinglei
authors.initials: J
authors.lastname: Shi
authors.forename: Jun
authors.initials: J
authors.lastname: Tang
authors.forename: Liwei
authors.initials: L
authors.lastname: Mao
authors.forename: Hongli
authors.initials: H
authors.lastname: Liu
authors.forename: Yijing
authors.initials: Y
authors.lastname: Deng
authors.forename: Yangdong
authors.initials: Y
authors.lastname: He
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Ruan
authors.forename: Jintao
authors.initials: J
authors.lastname: Li
authors.forename: Yuzhang
authors.initials: Y
authors.lastname: Wu
authors.forename: Bing
authors.initials: B
authors.lastname: Ni
mesh_terms: D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002448:Cell Adhesion; D002465:Cell Movement; D049109:Cell Proliferation; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D016503:Drug Delivery Systems; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D053758:Nanoparticles; D010957:Plasmids; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D012190:Retroviridae / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms / Q000235:genetics* / Q000628:therapy*
chemical_list: D004268:DNA-Binding Proteins; D039302:Integrin alphaVbeta3; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014157:Transcription Factors; C485514:ZBTB7A protein, human