Project description:The skeleton is the most common metastasis site of breast cancer cells and the molecular underpinning of this process is incompletely understood. The tumor suppressor gene deleted in liver cancer-1 (DLC1) encodes a multi-domain protein including a RhoGTPase activating protein (RhoGAP) domain and has been reported to suppress the lung colonization of breast cancer cells. However, the role of DLC1 in breast cancer bone metastasis and the importance of RhoGAP-dependent and -independent pathways in this process remain unclear. Here, we showed that DLC1 silencing is linked to enhanced bone-tropism of breast cancer cell lines and poor prognosis of clinical samples. In the study presented here, DLC1 was overexpressed in the SCP2 breast cancer cells, and the control SCP2 and overexpression cells were treated with TGFbeta. Microarray profiling of mRNA levels was performed in the control and overexpression cells with or without TGFbeta treatment.
Project description:The skeleton is the most common metastasis site of breast cancer cells and the molecular underpinning of this process is incompletely understood. The tumor suppressor gene deleted in liver cancer-1 (DLC1) encodes a multi-domain protein including a RhoGTPase activating protein (RhoGAP) domain and has been reported to suppress the lung colonization of breast cancer cells. However, the role of DLC1 in breast cancer bone metastasis and the importance of RhoGAP-dependent and -independent pathways in this process remain unclear. Here, we showed that DLC1 silencing is linked to enhanced bone-tropism of breast cancer cell lines and poor prognosis of clinical samples.
Project description: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).
Project description: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).