Abstract: Objective : To investigate the effects of antisense oligodeoxynucleotide (ASODN) for hTERT mediated by nanoparticles on esophageal carcinoma cells EC9706 in vitro. Methods : As an oligodeoxynucleotide carrier,the polybutylcyanoacrylate nanoparticle was prepared by emulsion polymerization method. The diameter and zeta potential were measured by atom force microscopy (AFM) and Nanosize machine, respectively. Theeight different ASODNs (NPs-ASODN Ⅰ, NPs-ASODN Ⅱ, NPs-ASODN Ⅲ, NPs-ASODN Ⅳ, NPs-ASODNⅤ, NPs-ASODN Ⅵ, NPs-ASODN Ⅶ and NPs-ASODN Ⅷ) for hTERT were transfected into EC9706 cells by polybutylcyanoacrylate nanoparticles (NPs). The MTT assay was used to detect the proliferation of EC9706cells. The level of hTERT mRNA expression was measured by RT-PCR. Apoptosis was detected by flow cy-tometry (FCM). Results : NPs with even size and smooth surface were successfully obtained. The inhibitory ef-fects of different NPs-ASODNs on the proliferation of EC9706 cells after transfection were time- and concen-tration-dependent. Significant differences were found in the inhibitory rates between NPs-ASODN transfected cells and the control cells (P<0.05). However, no significant inhibitory effect was observed in cells transfectedwith NPs, SODN or ASODN. At 72 hours after transfection, the level of hTERT mRNA in EC9706 cells was lower than that in the control cells (P<0.05). EC9706 cell apoptosis was seen in NPs-ASODN I, V, VI, VII, and VIII groups at 72 hour after transfection. No obvious apoptosis was found in the NPs-ASODN II, III, and IVgroups (P>0.05). Conclusion : NPs can be used as good gene carriers. ASODNs for hTERT mRNA mediatedby NPs can effectively inhibit the proliferation of EC9706 cells, decrease the level of hTERT mRNA, and in-duce EC9706 cell apoptosis in vitro, indicating that NPs may be used in targeted cancer therapy. The inhibito-ry effects are concentration-dependent, time-dependent, and sequence specific, indicating that differenthTERT gene points play different roles in telomerase activity.