目的: 观察选择性增殖腺病毒CNHK500对乳腺癌的特异性杀伤作用。方法: 行病毒增殖实验和细胞生长抑制实验，验证CNHK500选择性复制和杀伤能力； Western blot检测腺病毒E1A和E1B在细胞中的表达。 结果: CNHK500在乳腺癌细胞中复制能力与野生型腺病毒wtAd5相似,较ONYX-015增殖能力强。在正常成纤维细胞中CNHK500病毒增殖能力明显减弱， 较wtAd5增殖能力弱1 000倍左右。CNHK500可有效杀伤乳腺癌细胞株；而CNHK500对正常成纤维细胞的杀伤力较wtAd5减弱约100倍。CNHK500病毒的E1A可以选择性在端粒酶阳性的乳腺癌细胞株中表达，在端粒酶阴性的正常成纤维细胞株BJ中不表达， CNHK500可以选择性地在缺氧条件下表达E1B。动物实验结果显示，静脉注射CNHK500可以显著抑制MCF-7乳腺癌细胞裸鼠移植瘤的生长，治疗效果与给药剂量相关。结论： 肿瘤选择性增殖腺病毒CNHK500可选择性在端粒酶阳性的乳腺癌细胞中复制，并产生体内外杀伤作用

Objective: To evaluate the selectively oncolytic effect of conditionally replicating adenovirus CNHK500 in breast cancer. Methods: We used virus proliferation assay cell viability assay to evaluate the proliferation and cytolysis selectivity of CNHK500. And we used Western-blot to confirm the expression of adenovirus CNHK500 E1A and E1B in cancer and normal cells. Results: The CNHK500 virus proliferation ability in breast cancer cell lines is similar to that of wtAd5, better than that of ONYX-015 virus. However, CNHK500 virus replicate 1000-fold less than that of wtAd5 in normal fibroblast cell lines. CNHK500 can effectively kill breast cancer cell, while it shows attenuated cytolysis in normal fibroblast cells, with about 100-fold less than that of wtAd5. CNHK500 E1A is expressed in telomerase-positive breast cancer cells but not in telomerase-negative normal fibroblast cells. E1B protein can be detected under hypoxia condition but not in normoxia conditions. Intravenous injections of CNHK500, yielded significant tumor growth delay in the telomerase-positive breast cancer xenografts though the MCF-7 represent a very fast growing tumor cell line. Antitumor efficacy of replication-competent adenovirus CNHK500 in vivo was associated with increased dosage of CNHK500. Conclusions: The results prove that CNHK500 has highly proliferation selectivity and potent cytolysis effect on breast cancer.

国家863计划重点资助项目(2001AA217031); 国家自然科学基金国际合作项目(30120160824)