Pre-existing cell subpopulations in primary prostate cancers display surface fingerprint of docetaxel-resistant cells
BackgroundDocetaxel resistance represents a leading obstacle in the therapy of prostate cancer (PCa), resulting in lethal disease. Intratumoral heterogeneity, which is frequently driven by epithelial-mesenchymal plasticity significantly contributes to the limited treatment response, chemoresistance, and subsequent poor prognosis of patients with lethal PCa. MethodsWe employed a high-throughput flow cytometry screening to identify cell surface fingerprint that associates with docetaxel resistance in PCa cells. Using patient-derived xenografts, we validated protein expression of the most robustly changed antigens in vivo and further assessed this 6-molecule surface fingerprint in primary PCa tumors. ResultsWe revealed the overexpression of SSEA-4 antigen in both in vitro and in vivo docetaxel-resistant models and confirmed the SSEA-4 enrichment in a subpopulation of freshly isolated primary PCa tumors. The level of ST3GAL2, an enzyme that is critically involved in the SSEA-4 synthesis, correlated with increased expression of CD44, CD59, and CD95 and reduced expression of EpCAM and CD9. SSEA-4 was further directly linked to the antimicrotubule agent resistance and poor prognosis in PCa patients. ConclusionsWe propose that the 6-molecule surface fingerprint associates with docetaxel resistance and pre-exists in a cell subpopulation of primary PCa tumors even before docetaxel treatment.