目的:观察肿瘤选择性增殖腺病毒CNHK300对HER-2高表达乳腺癌细胞株的杀伤作用。方法: 用TRAP-ELISA方法检测乳腺癌细胞株(MDA-MB-453、SK-BR-3）和正常成纤维细胞株MRC-5的端粒酶活性；进行病毒增殖实验和细胞生长抑制实验，并与野生型腺病毒wtAd5进行对比,验证CNHK300选择性复制和选择性杀伤能力；用细胞生长抑制实验进一步考察CNHK300与化疗药物紫杉醇联合应用对乳腺癌细胞的杀伤作用；用Western blot检测腺病毒E1A在细胞中的表达。结果: 乳腺癌细胞株端粒酶均为阳性，而MRC-5正常成纤维细胞株端粒酶为阴性。CNHK300在乳腺癌细胞中的病毒增殖能力与野生型腺病毒相似,两者也具有相似的肿瘤细胞杀伤能力。在MRC-5正常成纤维细胞中,CNHK300病毒增殖能力较wtAd5明显减弱,同时对正常成纤维细胞的杀伤力明显减弱。CNHK300病毒和紫杉醇联合应用，较同样剂量的两者单独应用,细胞存活率明显下降。CNHK300病毒E1A可以选择性地在端粒酶阳性的乳腺癌细胞中表达，在端粒酶阴性的正常成纤维细胞中不表达。结论: 肿瘤选择性增殖腺病毒CNHK300可选择性地在某些端粒酶阳性的乳腺癌细胞中复制，并产生溶瘤作用。与化疗药物紫杉醇联合应用可产生协同作用。

Objective: To evaluate the killing effect of tumor-selective replicating adenovirus CNHK300 combined with paclitaxel (chemotherapy agents) on human breast cancer cells over-expressing HER-2. Methods: The telomerase activity in breast cancer cells and MRC-5 cell line were detected semi-quantitively by TRAP-ELISA assay. Virus proliferation assay and cell viability assay were used to evaluate the proliferation and cytolysis selectivity of CNHK300, and the results were compared with those of wtAd5. The breast cancer cells were treated with CNHK300 combining paclitaxel to evaluate the killing effect of the combined regimen. Western-blot was used to detect the expression of adenovirus CNHK300 E1A in cancer and normal cells. Results: The telomerase activity of the 2 breast cancer cell lines were both positive, while telomerase in MRC-5 fibroblast cell was negative. The proliferative ability of CNHK300 virus and its killing effect on breast cancer cells were similar to those of wtAd5. However, CNHK300 exhibited attenuated replicative ability and killing effect in normal fibroblast cell line than wtAd5 did. Combination of CNHK300 and paclitaxel exhibited increased killing effect in breast cancer cells. CNHK300 E1A was expressed in telomerase-positive breast cancer cells but not in the telomerase-negative normal fibroblast cells.

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）