ANALYSIS OF THE HUMAN α6 INTEGRIN PROMOTER

点击翻译按钮获取中文摘要

Cell to matrix interactions play important roles in tumor metastasis. integrin α6 subunit associates with β1 or β4 subunit to form receptors for laminin, a major component of the basement membrane. The expression of integrin α6 subunit is thought to be important for tumor cell invasion through the basement membrane. To investigate the regulatory mechanism of integrin α6 gene we previously cloned 5' flanking region of the human α6 integrin. The promoter region contained a TATA-like sequence, consensus binding sites for Sp1 and NF-κB. A putative GRE/PRE, together with Ap1 and c-myc binding sites were located around 350-360 bp upstream of the transcription start site. We analyzed the methylation of CpG loci around Ap1 and c-myc binding sites. DNA extracted from cultured breast cancer cell lines showed higher methylation than that from prostate cancer cell lines by Southern blotting after the restriction enzyme digestion as well as by the sodium bisulfite-modified sequencing analysis. Thus DNA methylation around Ap1 and c-myc binding sites of the human α6 integrin gene promoter might regulate, in part, the gene expression in breast cancer cells.We established the methods to detect methylated-cytosine residue of gene promoter from formalin-fixed paraffin-embedded histological specimen. We furthermore continue to analyze the effects of DNA methylation of human α6 integrin promoter on expression of the gene using archived pathological samples of the cases with breast cancer. To assess the expression of genes of cell adhesion molecules and extracellular matrices on cancer tissues, we set up the system of in situ hybridization using PCR-derived single stranded DNA probes. We have presented our data at various international as well as domestic meetings, and publish a lot of scientific papers for academic journals.