Stromal Mesenchyme Cell Genes in Prostate Cancer Development: Epigenetic Markers for Cancer and Potential Targets for Therapy

Functional development of the prostate is governed by stromal induction and epithelial response. Stromal/epithelial signaling can be mediated through direct cell-cell contact and diffusible factors with their cell surface receptors. One approach to gain a molecular understanding of epithelial/stromal interaction is to identify the organ-specific stromal signaling factors. We proposed to do this through a comparative analysis between prostate stromal and bladder stromal cells. For the prostate/bladder transcriptome analysis, we isolated stromal cell populations by the use of specific CD markers: CD49a for prostate and CD13 for bladder with magnetic cell sorting (MACS) and laser-capture microdissection (LCM). The Affymetrix microarray platform was used to determine the cell type-specific transcriptomes. The glycopeptide-capture method was used to profile protein expression differences because most secreted proteins are glycosylated. We have identified an increased expression in prostate stromal cells of signal transducers like AXL receptor tyrosine kinase, and protein tyrosine kinase 7, which have been implicated in tumor progression. Western blot analysis was performed to validate their expression. Our comparative stable isotope-free proteomic analysis using a modification of the N-linked glycopeptide-capture method allowed facile measurement of changes in protein expression. A number of secreted proteins which may be involved in stromal/epithelial signaling and organ-specific differentiation were identified. The original document contains color images.