Environmental microcystin exposure triggers the poor prognosis of prostate cancer: Evidence from case-control, animal, and in vitro studies

Microcystin-leucine-arginine(MC-LR)is positively linked with multiple cancers in humans.However,the association between MC-LR and the risk and prognosis of prostate cancer has not been conducted in epidemiological studies.No reported studies have linked MC-LR exposure to the poor prognosis of prostate cancer by conducting experimental studies.The content of MC-LR was detected in most of the aquatic food in wet markets and supermarkets in Nanjing and posed a health risk for consumers.MC-LR levels in both prostate cancer tissues and serum were significantly higher than controls.The adjusted odds ratio(OR)for prostate cancer risk by serum MC-LR was 1.75(95%CI:1.21-2.52)in the whole subjects,and a positive correlation between MC-LR and advanced tumor stage was observed.Survival curve analysis indicated patients with higher MC-LR levels in tissues exhibited poorer overall survival.Human,animal,and cell studies confirmed that MC-LR exposure increases the expression of estrogen receptor-α(ERα)and promotes epithelial-mesenchymal transition(EMT)in prostate cancer.Moreover,MC-LR-induced decreased E-cadherin levels,increased vimentin levels,and increased migratory and invasive capacities of prostate cancer cells were markedly suppressed upon ERαknockdown.MC-LR-induced xenograft tumor growth and lungmetastasis in BALB/c nude mice can be effectively alleviated with ERαknockdown.Our data demonstrated that MC-LR upregulated vimentin and downregulated E-cadherin through activating ERα,promoting migration and invasion of prostate cancer cells.Our findings highlight the role of MC-LR in prostate cancer,providing new perspectives to understand MC-LR-induced prostatic toxicity.