Knockdown of Efp by DNA-modified small interfering RNA inhibits breast cancer cell proliferation and in vivo tumor growth.
The estrogen-responsive gene Efp promotes the growth of breast cancer cells by stimulating the degradation of a negative cell-cycle regulator, 14-3-3sigma, and is hence considered a suitable molecular target for breast cancer therapy. The use of small interfering RNA (siRNA) and its derivatives to silence cancer-related genes is being investigated with the aim of identifying clinical applications for these molecules. Recently, it has been shown that DNA-modified siRNA (chimeric siRNA) has good potential in clinical applications, because it induces fewer off-target effects or immune responses in mammalian cells. In the present study, we identified the most specific and effective siRNA (siEfp-1) for silencing Efp expression in MCF-7 breast cancer cells. For this purpose, we used an algorithm that primarily eliminates off-target effects. siEfp-1 considerably suppressed the in vitro proliferation and cell-cycle progression of MCF-7 cells, as well as the in vivo growth of MCF-7 tumors, in athymic mice. DNA-modified siEfp-1 (chimeric siEfp) significantly inhibited the expression of Efp, proliferation of cultured cells and the in vivo growth of MCF-7-derived tumors in athymic mice. In addition, the silencing of Efp expression by siEfp-1 and chimeric siEfp increased the expression of the 14-3-3sigma protein. These results suggest that siEfp-1 and chimeric siEfp could be useful in breast cancer therapy. Chimeric siEfp, in particular, has a high specificity and induces few side effects and is therefore expected to be used as a novel nucleic acid-based therapeutic agent.
Ueyama
K
K
Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Hidaka, Saitama, Japan.
Ikeda
K
K
Sato
W
W
Nakasato
N
N
Horie-Inoue
K
K
Takeda
S
S
Inoue
S
S
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology*; D002453:Cell Cycle; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004247:DNA / Q000008:administration & dosage / Q000737:chemistry* / Q000235:genetics; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014157:Transcription Factors; D000070584:Tripartite Motif Proteins; D004247:DNA; C084523:TRIM25 protein, human; D044767:Ubiquitin-Protein Ligases