Wang Che, Chen Yin-Wang, Zhang Liang, Gong Xian-Ge, Zhou Yang, Shang De-Jing
a Department of Pharmacy , School of Chemistry and Chemical Engineering, Liaoning Normal University , Dalian , China and.
b Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery , School of Life Science, Liaoning Normal University , Dalian , China.
J Drug Target. 2016;24(6):548-56. doi: 10.3109/1061186X.2015.1113539. Epub 2015 Nov 23.
We have previously reported that temporin-1CEa, a cationic antimicrobial peptide, exerts preferential cytotoxicity toward cancer cells. However, the exact molecular mechanism for this cancer-selectivity is still largely unknown. Here, we found that the negatively charged phosphatidylserine (PS) expressed on cancer cell surface serves as a target for temporin-1CEa. Our results indicate that human A375 melanoma cells express 50-fold more PS than non-cancerous HaCaT cells. The expression of cell surface PS in various cancer cell lines closely correlated with their ability to be recognized, bound and killed by temporin-1CEa. Additionally, the cytotoxicity of temporin-1CEa against A375 cells can be ameliorated by annexin V, which binds to cell surface PS with high affinity. Moreover, the data of isothermal titration calorimetry assay further confirmed a direct binding of temporin-1CEa to PS, at a ratio of 1:5 (temporin-1CEa:PS). Interestingly, the circular dichroism spectra analysis using artificial biomembrane revealed that PS not only provides electrostatic attractive sites for temporin-1CEa but also confers the membrane-bound temporin-1CEa to form α-helical structure, therefore, enhances the affinity and membrane disrupting ability of temporin-1CEa. In summary, these findings suggested that the melanoma cells expressed PS may serve as a promising target for temporin-1CEa or other cationic anticancer peptides.
我们之前报道过，阳离子抗菌肽天蚕素-1CEa对癌细胞具有优先细胞毒性。然而，这种癌症选择性的确切分子机制仍 largely未知。在这里，我们发现癌细胞表面表达的带负电荷的磷脂酰丝氨酸（PS）是天蚕素-1CEa的靶点。我们的结果表明，人A375黑色素瘤细胞表达的PS比非癌细胞HaCaT细胞多50倍。各种癌细胞系中细胞表面PS的表达与其被天蚕素-1CEa识别、结合和杀伤的能力密切相关。此外，膜联蛋白V可以改善天蚕素-1CEa对A375细胞的细胞毒性，膜联蛋白V能以高亲和力结合细胞表面的PS。此外，等温滴定量热法测定的数据进一步证实了天蚕素-1CEa与PS以1:5（天蚕素-1CEa:PS）的比例直接结合。有趣的是，使用人工生物膜的圆二色光谱分析表明，PS不仅为天蚕素-1CEa提供静电吸引位点，还使膜结合的天蚕素-1CEa形成α-螺旋结构，因此增强了天蚕素-1CEa的亲和力和膜破坏能力。总之，这些发现表明黑色素瘤细胞表达的PS可能是天蚕素-1CEa或其他阳离子抗癌肽的一个有前景的靶点。
