Development of a three-dimensional culture model of prostatic epithelial cells and its use for the study of epithelial-mesenchymal transition and inhibition of PI3K pathway in prostate cancer.
Appropriate 3D culture models of human prostatic epithelial cells resembling normal growth pattern and architecture of prostate gland and its malignant development are scarce. Here, we optimized the 3D culture conditions of the immortalized non-transformed human prostatic epithelial cell line BPH-1 in Matrigel and developed a 3D culture model closely mimicking prostatic glandular structure. Our results showed that BPH-1 cells cultured in Matrigel formed acinus-like spheroids with lumen formation and polarized differentiation. To establish an androgen-stimulated differentiation in AR-negative BPH-1, we generated AR-transduced BPH-1 cells, which displayed androgen-induced secretory differentiation and growth suppression in 3D culture. We also evaluated the spheroid forming capacity of tumorigenic derivative BPH-1(CAFTD) sublines in 3D culture and their responses to PI3K inhibitor LY294002. Results showed that these tumorigenic BPH-1(CAFTD) sublines did not exhibit polarized differentiation in Matrigel culture. Interestingly, polarization could be restored by LY294002 treatment of BPH-1(CAFTD1) but not of BPH-1(CAFTD3) subline. Finally, we employed this 3D culture model to examine the significance of an EMT-regulatory transcription factor Snail in prostate cancer development by its stable transduction into BPH-1 cells. Results showed that BPH-1-Snail cells lost their spheroid forming capacity and exhibited an invasive phenotype. Taken together, we established a 3D culture model of human prostatic epithelial cells with structural and functional relevance to normal prostate gland and prostate cancer development and also demonstrated that this 3D model might be useful to assess the ability of drugs to restore differentiation as a potential surrogate measure of efficacy for prostate cancer therapy.