Abstract | AIM: METHODS: Endogenous c-Myc suppression and apoptosis induction by a transient FIR-expressing vector was examined in vivo via a HA-tagged FIR (HA-FIR) expression vector. A fusion gene-deficient, non-transmissible, Sendai virus (SeV) vector encoding FIR cDNA, SeV/dF/FIR, was prepared. SeV/dF/FIR was examined for its gene transduction efficiency, viral dose dependency of antitumor effect and apoptosis induction in HeLa (cervical squamous cell carcinoma) cells and SW480 ( colon adenocarcinoma) cells. Antitumor efficacy in a mouse xenograft model was also examined. The molecular mechanism of the anti- tumor effect and c-Myc suppression by SeV/dF/FIR was examined using Spliceostatin A (SSA), a SAP155 inhibitor, or SAP155 siRNA which induce c-Myc by increasing FIR∆exon2 in HeLa cells. RESULTS: FIR was found to repress c-myc transcription and in turn the overexpression of FIR drove apoptosis through c-myc suppression. Thus, FIR expressing vectors are potentially applicable for cancer therapy. FIR is alternatively spliced by SAP155 in cancer cells lacking the transcriptional repression domain within exon 2 (FIR∆exon2), counteracting FIR for c-Myc protein expression. Furthermore, FIR forms a complex with SAP155 and inhibits mutual well-established functions. Thus, both the valuable effects and side effects of exogenous FIR stimuli should be tested for future clinical application. SeV/dF/FIR, a cytoplasmic RNA virus, was successfully prepared and showed highly efficient gene transduction in in vivo experiments. Furthermore, in nude mouse tumor xenograft models, SeV/dF/FIR displayed high antitumor efficiency against human cancer cells. SeV/dF/FIR suppressed SSA-activated c-Myc. SAP155 siRNA, potentially produces FIR∆exon2, and led to c-Myc overexpression with phosphorylation at Ser62. HA-FIR suppressed endogenous c-Myc expression and induced apoptosis in HeLa and SW480 cells. A c-myc transcriptional suppressor FIR expressing SeV/dF/FIR showed high gene transduction efficiency with significant antitumor effects and apoptosis induction in HeLa and SW480 cells. CONCLUSION: SeV/dF/FIR showed strong tumor growth suppression with no significant side effects in an animal xenograft model, thus SeV/dF/FIR is potentially applicable for future clinical cancer treatment.
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Authors | Kazuyuki Matsushita, Hideaki Shimada, Yasuji Ueda, Makoto Inoue, Mamoru Hasegawa, Takeshi Tomonaga, Hisahiro Matsubara, Fumio Nomura |
Journal | World journal of gastroenterology
(World J Gastroenterol)
Vol. 20
Issue 15
Pg. 4316-28
(Apr 21 2014)
ISSN: 2219-2840 [Electronic] United States |
PMID | 24764668
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- DNA, Complementary
- FARP2 protein, human
- Guanine Nucleotide Exchange Factors
- Pyrans
- RNA Splicing Factors
- RNA-Binding Proteins
- Repressor Proteins
- Spiro Compounds
- poly-U binding splicing factor 60KDa
- spliceostatin A
- Green Fluorescent Proteins
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Topics |
- Animals
- Apoptosis
- Cell Line, Tumor
- Cell Survival
- Colonic Neoplasms
(metabolism, therapy)
- DNA, Complementary
(metabolism)
- Genes, myc
- Genetic Vectors
- Green Fluorescent Proteins
(metabolism)
- Guanine Nucleotide Exchange Factors
(genetics, metabolism)
- HeLa Cells
- Humans
- Male
- Mice
- Mice, Inbred BALB C
- Neoplasm Transplantation
- Phosphorylation
- Plasmids
(metabolism)
- Pyrans
(chemistry)
- RNA Splicing Factors
- RNA-Binding Proteins
(genetics, metabolism)
- Repressor Proteins
(genetics, metabolism)
- Sendai virus
(genetics)
- Spiro Compounds
(chemistry)
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