Please note that we have stopped the regular imports of Gene Expression Omnibus (GEO) data into ArrayExpress. This may not be the latest version of this experiment.
E-GEOD-40558 - Involvement of transcription factor early growth response 4 (EGR4) in lung cancer bone metastasis
Released on 1 April 2013, last updated on 2 June 2014
EGR4 (early growth response 4), a transcription factor, was previously shown to be up-regulated in lung cancer bone metastasis, compared with its expression in metastasis in other organs, using a multiorgan metastasis model of human small-cell lung cancer cells (SBC-5) in NK cell-depleted SCID mice (Kakiuchi S et al. Mol Cancer Res 2003). Here we show that EGR4 was essential for survival cancer cells, and migration ability. Next, in searching of downstream genes regulated by EGR4, we analyzed the changes in transcriptomes of SBC-5 cells at different time-points (24, 48 and 72 hr) when knockdown of EGR4 by siRNA. Lots of genes were identified either up-regulated or down-regulated in siEGR4 samples compared with control siRNA. Among these genes, there were genes with roles in metastasis or bone biology. The fact that EGR4 knockdown led to up-regulation or suppression of these genes also indicated dual roles of EGR4 in transcriptional regulation, which is consistent with previous reports: EGR4 may repress its own promoter (Zipfel PF et al. Biochim Biophys Acta. 1997) or activate certain inflammatory genes (Decker EL et al. Nucleic Acids Res. 2003; Wieland GD et al. J Cell Sci. 2005). SBC-5 cells were cultured at 1x10^6 cells/2 ml in 3.5 cm plate. After seeding 24 hours, cells were transfected either siEGR4 or siEGFP (for control), using Lipofectamin. At 24, 48 and 72 hours after starting of siRNA, we extracted RNA from these cells, and subjected these RNAs to microarray analysis. The labeling, amplification, hybridization and microarray data analysis were described previously (Dat LT et al. Int J Oncol, 40: 1455-1469 2012).
transcription profiling by array
Le Tan Dat <firstname.lastname@example.org>, Atsushi Mitsuhashi, Hisatsugu Goto, Le T Dat, Masaki Hanibuchi, Saburo Sone, Soji Kakiuchi, Taisuke Matsuo, Takuya Kuramoto, Tetsuro Yoshimaru, Toyomasa Katagiri, Yasuhiko Nishioka