OBJECTIVETo assess the effects of LiCl on prostate cancer growth and to explore the underlying mechanisms.

METHODSEffects of LiCl on cell growth in vitro and in vivo were determined by cell counting and xenografts of prostate cancer cells. Alterations in cell proliferation and the expression of DNA replication-related protein were determined by MTT assay, BrdU incorporation and Western blot.

RESULTSCompared to PBS control group, the number of prostate cancer cells (PC-3) were lower treated with 10 mmol/L LiCl, the number was 1.9×10(5), 4.8×10(5) and the difference was significant (P < 0.05). The inhibition rate of cellular proliferation were 50%, 95% and 98%, respectively, in LiCl group, NaCl and KCl control group, the difference was significant (P < 0.05). The A-Value of BrdU incorporation was 1.5, 1.3 treated with 10 mmol/L, 30 mmol/L LiCl, while the A-value of BrdU incorporation was 4 in PBS control group, the difference was significant (P < 0.05). On the protein level, LiCl downregulates expression of cdc 6, cyclins A and cyclins E, and cdc 25C, and upregulates expression of the CDK inhibitor p21(CIP1). The mean volume and weight of xenograft tumor were 50 mm(3) and 296 mg after LiCl intraperitoneal injection, But PBS control group were 180 mm(3) and 957 mg, the difference was significant (P < 0.05).

CONCLUSIONLiCl disrupts DNA replication and suppresses tumor growth of prostate cancer cells in vitro and in vivo.