目的·制备包载辣根过氧化物酶（horseradish peroxidase，HRP）和阿霉素（doxorubicin，DOX）的DNA纳米花（DNA nanoflowers，DF），探究其对小鼠Lewis肺癌（Lewis lung carcinoma，LLC）细胞的抑癌作用。方法·通过滚环扩增反应（rolling circle amplification，RCA）合成包载HRP的DF，即HRP-DF，并负载DOX制备DOX/HRP-DF。扫描电子显微镜和激光粒度仪检测其物理特性。利用酸性缓冲溶液检验DOX/HRP-DF的体外药物释放能力。通过CCK-8实验检测DOX/HRP-DF和游离DOX处理不同时间对人支气管上皮细胞16HBE的细胞毒性，评价DOX/HRP-DF的安全性。在缺氧环境下，利用氧敏感探针检测DOX/HRP-DF在LLC细胞中的氧气产生能力；通过CCK-8实验检测不同剂量的游离DOX、DOX-DF和DOX/HRP-DF对LLC细胞增殖能力的影响。设置不同剂量DOX/HRP-DF处理的实验组和PBS处理的对照组，通过划痕实验和Transwell小室实验检测DOX/HRP-DF对LLC细胞迁移和侵袭能力的影响。结果·成功制备DOX/HRP-DF，扫描电子显微镜下其呈花瓣状结构，大小均一，粒径为（415.90±9.32）nm，电位为（-17.43±1.20）mV；DOX的负载率为（38.19±0.39）%，且具有良好的pH敏感释药特性。DOX/HRP-DF能显著降低DOX对人类正常细胞的毒性作用。激光共聚焦显微镜观察显示DOX/HRP-DF能有效缓解LLC细胞的缺氧状况。CCK-8实验结果显示，与游离DOX组和DOX-DF组相比，DOX/HRP-DF组的LLC细胞增殖率显著降低，且呈剂量依赖性减少（均P<0.05）。细胞划痕实验结果显示，DOX/HRP-DF组的划痕愈合率与对照组相比呈剂量依赖性降低（均P<0.05）；Transwell小室实验结果显示，DOX/HRP-DF组穿过Matrigel基质胶的LLC细胞数量与对照组相比呈剂量依赖性减少（均P<0.05）。结论·成功制备的DOX/HRP-DF能安全有效传递药物，并缓解肿瘤微环境中乏氧情况，对LLC细胞的增殖、迁移和侵袭能力有显著抑制作用，有望为肺癌治疗提供新思路。

Objective ·To investigate the anti-cancer effects of DNA nanoflowers (DF) loaded with horseradish peroxidase (HRP) and doxorubicin (DOX) on mice Lewis lung carcinoma (LLC) cells. Methods ·The DF loaded with HRP (HRP-DF) was synthesized by rolling circle amplification (RCA) reaction and DOX was loaded to prepare DOX/HRP-DF, the physical properties of which were detected by scanning electron microscopy and laser particle sizer. In vitro drug release capacity of DOX/HRP-DF was tested with acid buffer solution. The safety of DOX/HRP-DF was evaluated by CCK-8 assay to detect the cytotoxicity of 16HBE cells treated with DOX/HRP-DF and free DOX at different time points. Under anoxic conditions, the oxygen production capacity of DOX/HRP-DF in LLC cells was detected by using the oxygen-sensitive probe, and the effects of different dosages of free DOX, DOX-DF and DOX/HRP-DF on the proliferation capacity of LLC cells were examined by CCK-8 assay. The effects of DOX/HRP-DF on the migration and invasion of LLC cells were detected by scratching assay and Transwell assay in the experimental group treated with different dosages of DOX/HRP-DF and the control group treated with Phosphate Buffered Saline (PBS). Results ·DOX/HRP-DF were successfully prepared and observed as flower-like structures under scanning electron microscopy with uniform size. The average diameter and potential of DOX/HRP-DF were (415.90±9.32) nm and (-17.43±1.20) mV, respectively. DOX/HRP-DF had a DOX loading of (38.19±0.39)% with good pH-sensitive drug release properties. DOX/HRP-DF could significantly reduce the toxic effect of DOX on human normal cells. The results of Laser confocal microscopy showed that DOX/HRP-DF could effectively alleviate the hypoxic condition of LLC cells. CCK-8 assay results showed that the proliferation rate of LLC cells in the DOX/HRP-DF group was significantly lower in a dose-dependent manner, compared to the free DOX and DOX-DF groups (P<0.05). The results of scratching assay showed that the scratch healing rate of the DOX/HRP-DF group was lower than that of PBS group in a dose-dependent manner (P<0.05). Transwell experiments showed the number of LLC cells passing through Matrigel gel in the DOX/HRP-DF group was reduced in a dose-dependent manner, compared with the PBS group (P<0.05). Conclusion ·The successfully prepared DOX/HRP-DF could effectively deliver drugs, and alleviate hypoxia in the tumor microenvironment, and significantly inhibit the proliferation, migration and invasion ability of LLC cells, which is expected to provide new ideas for lung cancer treatment.