Comparing gene-expression profiles between bone-metastatic vs. non bone-metastatic human prostate cancer cells

Disseminated prostate cancer cells colonize the skeleton to progress into macroscopic lesions only if they successfully adapt to the bone microenvironment. We previously reported that the ability of prostate cancer cells to generate skeletal tumors in animal models correlated with the expression of the alpha-receptor for Platelet-Derived Growth Factor (PDGFRa). In this study we aimed to identify PDGFRa-regulated genes responsible for the acquisition of a bone-metastatic prostate phenotype. We performed genome-wide expression comparative analyses of human prostate cancer cell lines that differ for PDGFRa expression and propensity to establish tumors in the skeleton of animal models. We investigated the genes that were differentially regulated in the highly bone-metastatic PC3-ML cells and their low-metastatic counterpart PC3-N cells, and the genes differentially regulated between PC3-N and PC3-N with overexpression of PDGFRa (PC3NRa). We have previously shown that DU-145 cells lack PDGFRa and fail to survive longer than three days as disseminated tumor cells after homing to the mouse bone marrow. Interestingly, and in contrast to PC3-N cells, the exogenous expression of PDGFRa did not promote metastatic bone-tropism of DU-145 cells in our model. Thus, we examined the genes that were differentially regulated between DU-145 and DU-145(Ra) and excluded them from our candidate genes. Finally, to refine our findings and compensate for PC3 and DU-145 genetic disparity, we performed a comparative analysis of the genes differentially regulated between two bone metastatic single-cell progenies that were derived from PC3-ML cells. Seven human prostate cancer cell lines were analyzed in total for this study. Each cell line was analyzed in duplicate from two different passages in culture.