Project description:This SuperSeries is composed of the following subset Series: GSE18182: Expression profile of lung adenocarcinoma, A549 cells following targeted depletion of non metastatic 2 (NME2/NM23 H2) GSE18284: Genomic binding sites of non-metastatic 2 (NME2) across promoters in lung cancer A549 cells Refer to individual Series
Project description:Non-metastatic 2 (NME2) is an established metastases suppressor in multiple human cancer types. However, the molecular mechanisms of NME2 action remain insufficiently resolved. We recently validated the transcription regulatory activity of NME2 with respect to control of proto-oncogene c-MYC expression. We hypothesized that large scale transcriptional potential of NME2 may be at the core of metastases suppression by NME2. Using a combination of high throughput genomic assays such as chromatin immunoprecipitation coupled to promoter array hybridization (ChIP-chip) and gene expression profiling, we characterized the transcriptional roles of NME2. Specifically, we found a set of NME2 target genes which changed expression upon selective depletion of NME2 in a lung cancer cell line, A549. The analysis of gene expression suggested control of various biological pathways esp. cell adhesion and apoptosis by NME2 target genes which could be important in regulation of metastases. For transcriptome analysis, total RNA was purified from A549 cells transiently silenced for NME2 (siRNA duplex against NME2/ NM23 H2(Santa Cruz)) or transfected with control siRNA duplexes. Isolated RNA was converted to cDNA, transcribed in vitro to synthesize biotinylated cRNA, and hybridized to Affymetrix HG-U133 plus 2.0 GeneChip oligonucleotide microarrays, according to manufacturer’s instructions. Three biological replicates were averaged and significance analysis performed using GCOS (P <0.005 of fold change).
Project description:Non-metastatic 2 (NME2) is an established metastases suppressor in multiple human cancer types. However, the molecular mechanisms of NME2 action remain insufficiently resolved. We recently validated the transcription regulatory activity of NME2 with respect to control of proto-oncogene c-MYC expression. We hypothesized that large scale transcriptional potential of NME2 may be at the core of metastases suppression by NME2. Using a combination of high throughput genomic assays such as chromatin immunoprecipitation coupled to promoter array hybridization (ChIP-chip) and gene expression profiling, we characterized the transcriptional roles of NME2. Specifically, we found a set of NME2 target genes which changed expression upon selective depletion of NME2 in a lung cancer cell line, A549. The analysis of gene expression suggested control of various biological pathways esp. cell adhesion and apoptosis by NME2 target genes which could be important in regulation of metastases.
Project description:Non-metastatic 2 (NME2) is one of the first discovered suppressors of metastases. However, the molecular mechanisms underlying its anti-metatsic activity remain insufficiently characterized. We hypothesized that large scale transcriptional potential of NME2 might be at the core of this function. Using a combination of gene expression meta-analysis, and high throughput genomic assays, we explored the transcriptional targets of NME2. Specifically, we found >250 binding sites of NME2 across human gene promoters. Several of the novel targets identified in this way regulated cell adhesion and survival. We subsequently constructed NME2 target gene network which delineated a transcriptional program responsive to NME2 capable of restricting metastasis. Three sets of ChIP vs. mock-ChIP experiments were done. pcDNA plasmid was transfected to lung cancer, A549 cells to express NME2 tagged with MYC epitope which was subsequently immunoprecipitated using anti-MYC antibodies (after 48 hours of transfection). Non-specific IgG was used for mock immunoprecipitation.
Project description:Exogenous overexpression of the metastasis suppressor gene Nm23-H1 reduces the metastatic potential of multiple types of cancer cells. In addition, Nm23-H1 expression suppresses in vitro tumor cell motility and invasion, important correlates of metastasis. The molecular mechanism by which Nm23-H1 suppresses metastasis, motility and invasion has yet to be defined. However, mutational analysis of Nm23-H1 has revealed that substitution mutant P96S and S120G are unable to inhibit cell motility. To elucidate the molecular mechanism of Nm23-H1 motility suppression, we performed expression microarray analysis of an MDA-MB- 435 carcinoma cell line overexpressing wild-type Nm23-H1 and cross-compared the expression profile to lines expressing P96S and S120G mutants. Nine genes, MET, PTN, SMO, FZD1, L1CAM, MMP2, NETO2, CTGF and EDG2, were down regulated by wild-type but not by mutant Nm23-H1 expression (p<0.05). Reduced expression of these genes coincident with elevated Nm23-H1 expression was observed in human breast tumor cohorts, a panel of breast carcinoma cell lines and hepatocellular carcinomas from control and Nm23-M1 knockout mice. The functional significance of down regulated genes was assessed by transfection and in vitro motility assays. Only EDG2 overexpression significantly restored motility to Nm23-H1- suppressed cancer cells and it enhanced motility by 60-fold in these cells. In addition, silencing EDG2 expression with siRNA, reduced the motile phenotype of metastatic breast cancer cells. These data suggest that Nm23-H1 suppresses metastasis, at least in part, through downregulation of EDG2 expression and that compounds directed toward EDG2 may be useful for treating aggressive, low Nm23-H1-expressing breast tumors. Keywords: Human MDA-MB-435 Breast cancer derived cell lines