Human tumor cell lines treated with 5AZA-dC vs control untreated cells.

Equal amounts of test and reference cDNA Cy-labeled mRNA targets were competitively hybridized against a customized cDNA platform with 4,608 ORESTES (open reading frame expressed sequences tags) representing human genes. With this microarray experiment, we found that N-Myc downstream-regulated gene 4 (NDRG4) is silenced in tumor cells and acts as a mechanistic biomarker of metastasis in ductal invasive breast tumors. While aberrant NDRG4 silencing, by DNA hypermethylation, is significantly associated with the development of metastatic disease, downregulation of NDRG4 transcription and protein expression is functionally associated with enhanced lymph node adhesion and cell mobility. Based on following functional assays, we show that silencing of NDRG4 modulates integrin signaling by assembling β1-integrins into large punctate clusters at the leading edge of tumor cells to promote an “adhesive switch,” decreasing cell adhesion to fibronectin and increasing cell adhesion and migration towards vitronectin, an important component of human lymph nodes. Two condition experiments: untreated (Mock) vs 5Aza-dC treated cells (T1) (1uM, 6 days). Three tested human tumor cell lines: MCF-7 (breast cancer), MDA-MB231 (breast cancer) and MDA-MB435 (melanoma) and one cell line used as reference: non-tumor human mammary epithelial cell line HB4a. Two replicates per array. ---------------------------------------- The author is unable to extract data from the TIFF files thus this record is incomplete.