Abstract: OBJECTIVE To explore the effects of uroacitides(CDA-2) on the proliferation of RPMI 8226 cells and its mechanisms. METHODS The proliferative inhibition of CDA-2 on RPMI 8226 cells was detected by MTT and the drug concentrations for further researches were screened out. The apoptosis of RPMI8226 cells after treating with CDA-2 was analyzed by Hoechst33258 staining, Annexin-V/PI staining, PI staining, and DNA gel electrophoresis. Changes in the expression of caspase-8, caspase-3 and their active forms were tested by Western Blot. The expression of TNF, ADD and TRAF3 mRNA were detected by semi-quantitative RT-PCR. RESULTS CDA-2 inhibited the proliferation of RPMI8226 cells in a dose-dependent manner with the IC50 1.64 mg·mL^-1. Condensed nuclei and apoptotic body were found via Hoechst33258 fluorescence staining when cells were treated with CDA-2. Annexin-V/PI analysis showed that the proportion of early apoptotic cells raised in a time-dependent manner. Cell cycle analysis showed that the apoptotic peak was up-regulated and G1 phase was decreased in a dose-dependent manner. DNA gel electrophoresis revealed integer multiples of 180~200 bp “ladder” bands. Western blot revealed that the expression of caspase-8, caspase-3 was down-regulated, while the expression of active caspase-8, activecaspase-3 was increased as the exposed time extended. The semi-quantitative RT-PCR showed up-regulation of TNF, FADD, TRAF3 mRNA, which were associated with apoptosis. CONCLUSION CDA-2 inhibited the proliferation of RPMI8226 cells and induced apoptosis via death receptor pathway.