Gene expressional changes in prostate fibroblasts from cancerous tissue.

Prostate cancer is the most common type of cancer in men. It is assumed that the tumor microenvironment of the prostate contributes to invasion and metastasis. Stroma-epithelial crosstalk has shown to change with progression of prostate cancer, and thereby the stromal compartment might be an attractive target in diagnostic and therapeutic approaches to prostate cancer. The purpose of this project was to study the reciprocal influence between fibroblasts and cancer cells in prostate cancer. Prostate fibroblast primary cultures from areas with cancer and hyperplasia were cocultivated with cells of the PC-3 lineage. Gene expression profiles of both cell types were studied to reveal possible associations to cancer invasion and metastasis. There were 383 differentially expressed genes between fibroblasts from cancerous areas and fibroblasts from areas with hyperplasia before cocultivation with PC-3 cells. Several of the differentially expressed gene classes are associated with cancer development and metastasis. After cocultivation, there were 26 differentially expressed genes between cancerous and hyperplastic fibroblasts. There were only three differentially expressed genes between PC-3 cells that had been cocultivated with cancerous fibroblasts and PC-3 cells that had been cocultivated with hyperplastic fibroblasts. The fibroblasts from cancer areas showed a different expression pattern from the characteristics reported as reactive stroma in previous studies. We found tenascin C to be downregulated, which is contrary to previous findings. TGF-β3 and TGF-βR3 were also downregulated, which has been associated with disturbance of TGF-β signaling during prostate cancer progression. Cocultivation with PC-3 cells seems to make the cancerous and hyperplastic fibroblasts more alike each other, as the number of differentially expressed genes decreases. It is desirable to find out if the reduction in differential gene expression is attributable to that hyperplastic fibroblasts become more alike the cancerous fibroblasts or vice versa. Also, we think that the lower expression levels of c-Jun and c-Fos in cancerous fibroblasts without coculture may cause loss of normal fibroblast differentiation, proliferation and inflammatory response, and hence, favor the proliferation and invasion of cancer cells.