Based on previous evidence, in the present study, we investigated the antitumor mechanism of hUCMSCs in PC-3 prostate cancer cells and report that hUCMSCs induce antiproliferative and apoptotic effects in PC-3 cells via activation of JNK and inhibition of the PI3K/AKT pathway in either direct or indirect culture conditions. The gene discussed is MAPK8; the disease is prostate cancer.