Enhancement of cytotoxicity of antimicrobial peptide magainin II in tumor cells by bombesin-targeted delivery
Enhancement of cytotoxicity of antimicrobial peptide magainin II in tumor cells by bombesin-targeted delivery
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DOI：
10.1038/aps.2010.162
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Shan Liu;Hao Yang;L. Wan;H. Cai;Sheng-fu Li;You-ping Li;Jingqiu Cheng;Xiaofeng Lu
中科院分区：
文献类型：
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作者：
Shan Liu;Hao Yang;L. Wan;H. Cai;Sheng-fu Li;You-ping Li;Jingqiu Cheng;Xiaofeng Lu
目的：探讨抗菌肽magainin II （MG2）与肿瘤归巢肽bombesin结合后是否能增强其对肿瘤细胞的毒性。方法：将magainin II （MG2）连接到bombesin的n端，构建magainin II-bombesin偶联物（MG2B）。利用fmoc化学合成了这些肽。采用CCK-8细胞计数试剂盒定量测定该肽对癌细胞的体外细胞毒性。此外，在异种肿瘤移植模型中测定了该肽的体内抗肿瘤作用。结果：MG2B对癌细胞的ic50 （10 ~ 15 μmol/L）比未偶联的MG2 （125 μmol/L）低至少10倍。此外，与未结合的MG2相比，MG2B对癌细胞的结合亲和力更高。相比之下，与缺乏受体结合结构域的bombesin类似物偶联未能增加MG2的细胞毒性，这表明bombesin偶联通过改善结合增强了MG2在癌细胞中的细胞毒性。MG2B在体外选择性诱导癌细胞死亡，ic50为10 ~ 15 μmol/L，比正常细胞的ic50低6 ~ 10倍。MG2B（每天20 mg/kg，瘤内注射5 d）在MCF-7肿瘤移植小鼠中也表现出抗肿瘤作用。mg2b和pbs处理小鼠的肿瘤移植物平均重量分别为0.21±0.05 g和0.59±0.12 g。结论：AMPs与bombesin的结合可能是肿瘤靶向治疗的一种替代方法。
Aim:To investigate whether the conjugation of magainin II (MG2), an antimicrobial peptides (AMPs), to the tumor-homing peptide bombesin could enhance its cytotoxicity in tumor cells.Methods:A magainin II-bombesin conjugate (MG2B) was constructed by attaching magainin II (MG2) to bombesin at its N-terminus. The peptides were synthesized using Fmoc-chemistry. The in vitro cytotoxicity of the peptide in cancer cells was quantitatively determined using the CCK-8 cell counting kit. Moreover, the in vivo antitumor effect of the peptide was determined in tumor xenograft models.Results:The IC 50 of MG2B for cancer cells (10–15 μmol/L) was at least 10 times lower than the IC 50 of unconjugated MG2 (125 μmol/L). Moreover, the binding affinity of MG2B for cancer cells was higher than that of unconjugated MG2. In contrast, conjugation to a bombesin analog lacking the receptor-binding domain failed to increase the cytotoxicity of MG2, suggesting that bombesin conjugation enhances the cytotoxicity of MG2 in cancer cells through improved binding. Indeed, MG2B selectively induced cell death in cancer cells in vitro with the IC 50 ranging from 10 to 15 μmol/L, which was about 6–10 times lower than the IC 50 for normal cells. MG2B (20 mg/kg per day, intratumorally injected for 5 d) also exhibited antitumor effects in mice bearing MCF-7 tumor grafts. The mean weights of tumor grafts in MG2B-and PBS-treated mice were 0.21±0.05 g and 0.59±0.12 g, respectively.Conclusion:The results suggest that conjugation of AMPs to bombesin might be an alternative approach for targeted cancer therapy.