MAPK8 and prostate cancer: The results obtained with specific inhibitors of various pathways inferred that the antiproliferative effect induced by spisulosine in prostate cancer cells was independent of peroxisome proliferator-activated receptor gamma (PPARγ), p38/classical protein kinase C (PKCs) pathways, Jun N-terminal kinase (JNK), and phosphatidylinositol 3-kinase/(PI3K/Akt).