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Use of RNA interference to elucidate the effect of MYCN on cell cycle in neuroblastoma
Author(s) -
Woo ChanWook,
Tan Fei,
Cassano Hope,
Lee JungHwa,
Lee Kwang Chul,
Thiele Carol J.
Publication year - 2008
Publication title -
pediatric blood and cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.116
H-Index - 105
eISSN - 1545-5017
pISSN - 1545-5009
DOI - 10.1002/pbc.21195
Subject(s) - neuroblastoma , cyclin dependent kinase 6 , cell cycle , e2f , cancer research , rna interference , medicine , small interfering rna , cyclin dependent kinase 1 , gene , microbiology and biotechnology , biology , cyclin d1 , rna , cell culture , genetics
Background MYCN amplification marks poor prognosis in neuroblastoma (NB) tumors. In evaluating the mechanisms by which retinoic acid (RA) or nerve growth factor (NGF) decrease cell number in MYCN amplified NB cells, we have identified a number of proteins whose expression either decreases (E2F, CDC2, CDK6, cyclin dependent kinase activity) or increases (p27) in association with a decrease in MYCN expression. However, it was still unclear which were MYCN dependent effects or not. Procedure This study aimed to determine which changes in cell cycle gene expression are modulated as a consequence of the decrease in MYCN. We silenced MYCN expression using siRNA targeted to the coding region of MYCN. Then, by using siRNA transient transfections, we analyzed the change of cell cycle related genes and cell cycle in MYCN amplified NB cell lines. Results We demonstrate that expression of MYCN can be suppressed by almost 60% in MYCN amplified NB cell using siRNAs targeted to MYCN. Functionally, the decrease in MYCN leads to a decrease in cells in the S‐phase of the cell cycle. Decreases in MYCN are associated with decreases in E2F1‐2 and ID2 along with increases in p27 protein levels by post‐transcriptional modification. Moreover, we find that a decrease in MYCN is accompanied by a decrease in cdk6 mRNA and protein expression. Conclusions These results show that E2F and ID2 expression is associated with MYCN regulation and that cdk6 is a possible new transcriptional target of MYCN. Pediatr Blood Cancer 2008;50:208–212. © 2007 Wiley‐Liss, Inc.