SPOCK1 and posterior cortical atrophy: In order to determine whether API interferes with cell invasion by modulating SPOCK1 expression in PCa cells, we first evaluated endogenous protein expression levels of SPOCK1 in prostate epithelial PNT2 cells, the weakly malignant LNCaP cells, and the highly malignant DU145, PC3, and PC-3 M cells.