Identification of lipid-phosphatidylserine (PS) as the target of unbiasedly selected cancer specific peptide-peptoid hybrid PPS1
Identification of lipid-phosphatidylserine (PS) as the target of unbiasedly selected cancer specific peptide-peptoid hybrid PPS1
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DOI：
10.16632/oncotarget.8929
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发表时间：
2016-05-24
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影响因子：
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通讯作者：
Udugamasooriya, Damith Gomika
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作者：
Desai, Tanvi J.;Toombs, Jason E.;Udugamasooriya, Damith Gomika
磷脂酰丝氨酸（PS）是维持在细胞膜的内小叶上的阴离子磷脂，并且在恶性细胞中外化。我们之前通过利用来自同一患者的HCC 4017肺癌和HBEC 3 OKT正常上皮细胞，鉴定HCC 4017特异性肽-类肽杂合PPS 1，启动了针对与癌细胞不同的生物分子（例如蛋白质，脂质或碳水化合物）的仔细无偏选择。在目前的研究中，我们确定PS为PPS 1的靶点。我们使用ELISA样测定、脂质斑点印迹和基于脂质体的结合测定来验证PPS 1与PS的直接结合。此外，PPS 1还识别其他带负电荷的癌症特异性脂质，如磷脂酸、磷脂酰肌醇和磷脂酰甘油。PPS 1不与中性脂质结合，如在癌症中发现的磷脂酰乙醇胺和在正常细胞中发现的磷脂酰胆碱和鞘磷脂。此外，我们发现PPS 1的二聚体版本（PPS 1D 1）对将PS外化的肺癌细胞系表现出强烈的细胞毒性，但对正常细胞则不然。PPS 1D 1在荷H460肺癌异种移植物的小鼠中显示出有效的单药抗肿瘤活性，并增强了多西他赛的疗效。由于PS和阴离子磷脂外化在许多癌症类型中很常见，PPS 1可能是克服蛋白质靶向药物局限性的替代方案。
Phosphatidylserine (PS) is an anionic phospholipid maintained on the inner leaflet of the cell membrane and is externalized in malignant cells. We previously launched a careful unbiased selection targeting biomolecules (e.g. protein, lipid or carbohydrate) distinct to cancer cells by exploiting HCC4017 lung cancer and HBEC3OKT normal epithelial cells derived from the same patient, identifying HCC4017 specific peptide-peptoid hybrid PPS1. In this current study, we identified PS as the target of PPS1. We validated direct PPS1 binding to PS using ELISA-like assays, lipid dot blot and liposome based binding assays. In addition, PPS1 recognized other negatively charged and cancer specific lipids such as phosphatidic acid, phosphatidylinositol and phosphatidylglycerol. PPS1 did not bind to neutral lipids such as phosphatidylethanolamine found in cancer and phosphatidylcholine and sphingomyelin found in normal cells. Further we found that the dimeric version of PPS1 (PPS1D1) displayed strong cytotoxicity towards lung cancer cell lines that externalize PS, but not normal cells. PPS1D1 showed potent single agent anti-tumor activity and enhanced the efficacy of docetaxel in mice bearing H460 lung cancer xenografts. Since PS and anionic phospholipid externalization is common across many cancer types, PPS1 may be an alternative to overcome limitations of protein targeted agents.