Genomic and phenotypic analysis reveals a key role for CCN1 (CYR61) in BAG3-modulated adhesion and invasion
Journal
The Journal of Pathology
Date Issued
2009-04
Author(s)
Abstract
Chaperone protein quantity may regulate the balance of proteins involved in invasion and malignancy. BAG3 is a co-chaperone and pro-survival protein that has been implicated in adhesion, migration, and metastasis. We reported that BAG3 overexpression in MDA435 human breast cancer cells results in a significant decrease in migration and adhesion to matrix molecules that is reversed upon deletion of the BAG3 proline-rich domain (dPXXP). We now hypothesize that transcriptional analysis would identify proteins involved in matrixrelated processes that are regulated by BAG3 and/or its PXXP domain mutant. Expression array analysis of MDA435 cells overexpressing either wild-type BAG3 (FL) or dPXXP identified CCN1 as a BAG3 target protein. CCN1 is a known AP-1 target. Increased AP-1 transcriptional activity and AP-1 DNA-binding was found in MDA435 dPXXP cells. Consistent with these findings, CCN1 quantity and secretion were increased in dPXXP mutants but suppressed in FL cells; both BAG3 forms resulted in up-regulated CCN1 in HeLa cells. CCN1 silencing in the BAG3 FL overexpressors reduced the already low phospho-integrin β1 in response to attachment on collagen IV. Matrigel invasion of HeLa cells engineered with the BAG3 constructs was enhanced in FL cells and minimal in dPXXP cells. CCN1 silencing blocked a greater percentage of the serum-induced invasion in FL cells than in dPXXP cells. This implies a context-dependent function of BAG3 on CCN1 and thus mesenchymal behaviour. CCN1 may be necessary for adhesion and matrix-related signalling in FL cells, abrogating a negative signal of the PXXP domain when BAG3 is intact. We propose that BAG3 regulates CCN1 expression to regulate tumour cell adhesion and migration.
Subjects
Adhesion; BAG3; CCN1; Cyr61; Genomic analysis; Integrin engagement
Other Subjects
beta1 integrin; carrier protein; collagen type 4; cysteine rich protein 61; immunoglobulin enhancer binding protein; matrigel; proline; protein BAG3; transcription factor AP 1; unclassified drug; article; breast cancer; cancer cell; cell adhesion; cell invasion; controlled study; DNA binding; gel mobility shift assay; gene expression; gene overexpression; gene silencing; genetic transcription; genome analysis; HeLa cell; human; human cell; phenotype; priority journal; protein analysis; protein expression; protein secretion; protein targeting; upregulation; Adaptor Proteins, Signal Transducing; Antigens, CD29; Cell Adhesion; Cell Line, Tumor; Collagen; Cysteine-Rich Protein 61; Drug Combinations; Electrophoretic Mobility Shift Assay; Gene Expression Profiling; Gene Silencing; Genomics; Hela Cells; Humans; Laminin; Neoplasm Invasiveness; Oligonucleotide Array Sequence Analysis; Phosphorylation; Proteoglycans; RNA, Messenger; Up-Regulation
Type
journal article