目的：探究新型LL-37 杂合肽对乳腺癌MCF-7 细胞的抗肿瘤活性及其作用机制。方法:利用抗菌肽数据库（http://aps.unmc.edu/AP/main.php）筛选出人源的抗肿瘤抗菌肽，即LL-37 和中性粒细胞防御素-1（human neutrophil peptide 1，HNP-1），经生物信息学软件分析提取有效肽片段，改造整合成新型LL-37 杂合肽；采用CCK-8 法检测0~70 μmol/L 的新型LL-37 杂合肽对MCF-7 细胞和人正常乳腺细胞MCF10A增殖的影响，激光扫描共聚焦显微镜观察分析新型LL-37 杂合肽与肿瘤细胞的亲和能力，流式细胞仪检测新型LL-37 杂合肽和caspase 抑制剂对MCF-7 细胞凋亡和周期的影响。结果:经软件分析得出新型LL-37 杂合肽为水脂两亲性的阳离子多肽，可靶向性地抑制乳腺癌MCF-7 细胞的增殖（P<0.05），其IC50值为58.34 μmol/L，而对正常乳腺MCF10A细胞无明显抑制作用；新型LL-37 杂合肽与MCF-7 细胞具有较高的亲和力，可引起细胞周期阻滞于S期及显著增加细胞早期凋亡率（P<0.01）；但在加入caspase 抑制剂后，细胞周期阻滞及凋亡情况明显缓解（P<0.01）。结论:新型LL-37 杂合肽对乳腺癌MCF-7 细胞具有抗肿瘤活性，可能通过caspase依赖的信号通路阻滞细胞周期和诱导细胞凋亡。

Objective: To investigate the anti-tumor effect and mechanism of new LL-37 hybrid peptide on breast cancer MCF-7 cells.Methods: Human antimicrobial peptide LL-37 and human neutrophil peptide 1(HNP-1) were screened by using of Antimicrobial Peptides Database (http:// aps.unmc.edu/AP/main.php). The new LL-37 hybrid peptide was synthesized by integrating the active fragments,which were selected by bioinformatics analysis. The breast cancer MCF-7 cells and human normal breast MCF10A cells were treated with the new LL-37 hybrid peptides (0~70 μmol/L). Cell viability was monitored by CCK-8 assay and the affinity of the new LL-37 hybrid peptide with MCF-7 cells was observed using confocal laser scanning microscope (CLSM). The effects of LL-37 and caspase inhibitor on apoptosis and cell cycle of MCF-7 cells were measured by FCM (flow cytometry). Results: The new LL-37 hybrid peptide, as an amphiphilic cationic polypeptide, could selectively inhibit the proliferation of breast cancer MCF-7 cells (P<0.05) with an IC50 of 58.34 μmol/L, but exerted no significant effect on normal breast MCF10A cells. LL-37 peptide had high affinity with MCF-7 cells, which could cause S-stage stagnation and significantly increased early apoptosis (P<0.01); however, the cell cycle block and apoptosis were significantly attenuated after the treatment of caspase inhibitor (P<0.01). Conclusion: The new LL-37 hybrid peptide has anti-tumor activity on breast cancer MCF-7 cells, and could induce MCF-7 cells apoptosis possibly by arresting cell cycle via the caspase-dependent signaling pathway.

国家自然科学基金资助项目（No.81560668；81860719）；西藏民族大学校内科研基金资助项目（No.19MDQ02）