Phosphatidylserine Targeted Tumor Cell Lytic Peptoids

描述（由申请人提供）：靶向癌细胞的新药有望彻底改变癌症医学。因为它们是癌症特异性的，它们使身体的其他部分免受有毒副作用的影响。不幸的是，对于许多类型的癌症，合适的蛋白质靶标不可用，并且即使在蛋白质标志物可用于的肿瘤中，标志物表达也存在异质性。这限制了靶向药物对选定患者群体的有效性。因此，迫切需要一种全球癌症标志物。脂质磷脂酰丝氨酸（PS）普遍存在于肿瘤血管内皮上，而在健康正常组织中不存在。PS也在许多类型的癌细胞的表面上表达。为了特异性靶向PS，从大型文库中选择了称为类肽的肽样分子。在动物肿瘤模型中，二聚体形式的类肽通过溶解癌细胞的质膜和破坏肿瘤内的肿瘤血管来有效地杀死癌细胞。类肽对正常细胞没有影响。该提案的总体目标是开发这种类肽的不同版本，以识别更有效的化合物。类肽的分子结构将以2种方式修饰：（i）活性类肽将组装成多聚体形式（例如二聚体、三聚体、四聚体等）。以增强活性和（ii）活性序列将被修饰以改善PS识别。这些衍生物将在许多不同的癌症模型中测试特异性溶解活性;乳腺癌、前列腺癌、白血病、神经胶质瘤和肺癌。接下来，将研究PS靶向类肽的作用机制。预期类肽通过破坏肿瘤的血管，导致肿瘤细胞通过氧和营养物的饥饿而死亡，以及通过溶解PS阳性肿瘤细胞而起作用。动物研究将全面评估这些活动。类肽制备便宜、稳定，并且可以在结构上快速精制以获得最佳功效。因此，本研究中鉴定的类肽可能构成一类新的药物，有可能对多种类型癌症的治疗产生重大影响。

DESCRIPTION (provided by applicant): New drugs that target cancer cells promise to revolutionize cancer medicine. Because they are cancer-specific, they spare the rest of the body from toxic side effects. Unfortunately, suitable protein targets are not available for many types o cancer and there is heterogeneity in marker expression even in tumors for which protein markers are available. This limits the usefulness of targeted drugs to selected groups of patients. Thus, there is a pressing need for a global marker of cancer. The lipid phosphatidylserine (PS) is universally present on the tumor vascular endothelium and absent from healthy normal tissues. PS is also expressed on the surface of many types of cancer cells. To target PS specifically, a peptide-like molecule, called a peptoid, was selected from a large library. The dimeric version of the peptoid potently killed cancer cells by lysing their plasma membrane and disrupted tumor blood vessels inside tumors in an animal tumor model. The peptoid had no effect on normal cells. The overall goal of this proposal is to develop different versions of this peptoid to identify even more effective compounds. The molecular structure of the peptoid will be modified in 2 ways: (i) The active peptoid will be assembled into multimeric forms (e.g. dimers, trimers, tetramers etc.) to enhance the activity and (ii) The active sequence will be modified to improve PS-recognition. These derivatives will be tested for specific lytic activity in many different cancer models; breast, prostate, leukemia, glioma and lung. Next, the mechanism of action of the PS-targeting peptoids will be investigated. The peptoids are expected to act by destroying the tumor's blood vessels, resulting in death of tumor cells through starvation of oxygen and nutrients, and by lysing PS-positive tumor cells. Animal studies will comprehensively evaluate these activities. Peptoids are inexpensive to prepare, stable and can be rapidly refined structurally for optimal efficacy. Thus, the peptoids identified n this study could constitute a new class of drugs with the potential to make a major impact on the treatment of multiple types of cancer.