A novel proteomic coculture model of prostate cancer cell growth.

Chemotherapy and androgen ablation therapy are only temporarily effective against prostate cancer, and current studies are ongoing to test agents that target proteins responsible for autocrine and paracrine stimulated growth. Given limitations of current laboratory models to test the effect of these agents on cell growth and protein targets, we developed a coculture model that can distinguish paracrine stimulated growth and effects on proteins. We found that LNCaP prostate cancer cells and an immortalized rat prostate cell line transfected to overexpress the antiapoptotic resistance protein Bcl-2 were stimulated to grow (>2-fold increase, p < 0.01) through autocrine effects from additional cells in an upper chamber of our system. Using a proteomic approach with a two-dimensional differential in gel electrophoresis method to increase fidelity, four proteins were found to increase after autocrine induced growth stimulation. These proteins were all identified by mass spectrometry as enzymes in the glycolytic pathway, validating the ability of this system to detect both clonogenic growth and the effect on proteins. These data, therefore, demonstrate a novel coculture model for further study of agents that target proteins in pathways of paracrine or autocrine stimulated cell growth.