ObjectiveTo explore apoptosis-inducing effect of lanthanum chloride in cervical cancer cells in vitro and the related mechanism, so as to provide a theoretical basis for medical use of rare earth complex. MethodsThe anti-tumor activity of lanthanum chloride against HeLa cells was examined by morphological observation and MTT (3-\[4,5-dimethylthiazol-2-yl\] -2,5-diphenyltetrazolium bromide) assay. Distribution of cell cycle and cell apoptosis were analyzed using flow cytometry (FCM). The expression and activation of Caspase-3 were examined by Western blotting assay and spectrophotometry. ResultsMorphological observation and MTT assay showed that lanthanum chloride significantly induced apoptosis in HeLa cells and inhibited cell growth in a dose-dependent manner(P<0.05). FCM analysis showed that the cell ratio of G0/G1 phase increased and that of S phase decreased significantly with the increase of lanthanum chloride doses. Lanthanum treatment also induced cell apoptosis dose-dependently. The minimum dose of lanthanum chloride to trigger apoptosis was 5 μmol/L, and the apoptosis rate increased in a dose-dependent manner compared with the control group (P＜0.01). Western blotting analysis showed that lanthanum chloride up-regulated Caspase-3 expression in a dose-dependent manner. Conclusion Lanthanum chloride can inhibit growth of human cervical cancer HeLa cells and induce cell apoptosis via Caspase pathway.