Recently, we reported that human breast cancer-associated fibroblasts show functional inactivation of the retinoblastoma (RB) tumor suppressor and down-regulation of caveolin-1 (Cav-1) protein expression. However, it remains unknown whether loss of Cav-1 is sufficient to confer functional RB inactivation in mammary fibroblasts. To establish a direct cause-and-effect relationship, mammary stromal fibroblasts (MSFs) were prepared from Cav-1(-/-) null mice and subjected to phenotypic analysis. Here, we provide evidence that Cav-1(-/-) MSFs share many characteristics with human cancer-associated fibroblasts. The Cav-1(-/-) MSF transcriptome significantly overlaps with human cancer-associated fibroblasts; both show a nearly identical profile of RB/E2F-regulated genes that are up-regulated, which is consistent with RB inactivation. This Cav-1(-/-) MSF gene signature is predictive of poor clinical outcome in breast cancer patients treated with tamoxifen. Consistent with these findings, Cav-1(-/-) MSFs show RB hyperphosphorylation and the up-regulation of estrogen receptor co-activator genes. We also evaluated the paracrine effects of "conditioned media" prepared from Cav-1(-/-) MSFs on wild-type mammary epithelia. Our results indicate that Cav-1(-/-) MSF "conditioned media" is sufficient to induce an epithelial-mesenchymal transition, indicative of an invasive phenotype. Proteomic analysis of this "conditioned media" reveals increased levels of proliferative/angiogenic growth factors. Consistent with these findings, Cav-1(-/-) MSFs are able to undergo endothelial-like transdifferentiation. Thus, these results have important implications for understanding the role of cancer-associated fibroblasts and RB inactivation in promoting tumor angiogenesis.
Pubmed ID: 19234134 RIS Download
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Database which provides on-line searching of microarray datasets generated from rat spinal cord after contusion injury. Both the primary injury site and a site 5 mm distal to the injury site were assayed. Tissue was obtained from Long Evans rats subject to spinal cord contusion injury using the MASCIS impactor (formerly known as the NYU impactor). RNA expression was assayed at the site of injury and distal to the site of injury using the Affymetrix Rat Neuro U34 chip.
View all literature mentionsPowerful, accessible statistical tools for fast visualization and analysis of microarrays - expression arrays, miRNA, exon arrays and genomics copy number data.
View all literature mentionsSoftware that allows users to manually or automatically design custom primers and probes for gene quantitation and allelic discrimination (SNP) real-time PCR applications. It supports assays based on TaqMan and SYBR Green I dye chemistries.
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