An integrated biophysics approach towards realisation of a new class of membrane-active anticancer therapies

众所周知，生物体产生其自身的抗生素宿主防御肽，其通过破坏细菌膜起作用，这是由于其与宿主生物体自身细胞相比的不同分子组成。这些抗微生物肽中的一些也已知具有抗癌特性。一种特别有前途的抗癌肽是来自巴西黄蜂保利斯塔Polybia毒液的Polybia MP 1（MP1）。最近，我们发现MP1的膜破坏作用被两类脂质PE和PS显著放大，这两类脂质在癌细胞表面的组成比正常组织的细胞高得多。因此，MP1是一个有前途的候选肽开发一种新的抗癌药物。该项目旨在优化这种肽的效力和特异性，以产生有前途的化合物，用于进一步的临床开发。通过我们目前对其相互作用机制的理解以及这与分子结构的关系，我们将产生一组氨基酸组成预定单一变化的MP1衍生肽。将筛选这些肽对具有代表癌症和正常细胞以及癌症和正常细胞系的组成的模型膜的活性。与MP1相比显示出增强的效力或特异性的突变将在第二轮设计的肽和活性筛选中组合。来自该筛选阶段的最有希望的肽将被用于更详细地表征它们与膜和细胞的相互作用。我们将使用一种新的方法，利用不同的见解，我们可以从系统的复杂性不断增加，从最小的膜模型与简化的脂质混合物代表的关键组成内容的相关细胞，膜提取相关的细胞，细胞本身。这将允许从模型膜获得的详细生物物理信息与整个细胞中的复杂生物反应之间的前所未有的相关性。的细胞系的脂质组合物也将被表征，与特别感兴趣的膜的组合物是最敏感的和那些是最耐肽诱导的膜disruption.Application的高灵敏度的表面分析和光学显微镜技术将提供详细的洞察肽膜相互作用的性质。重要的是，除了抗癌肽的开发之外，这些信息将有助于对肽结构、膜组成和相互作用机制之间的关系的有价值的基本见解，这将用于开发广泛的膜活性肽，包括抗微生物肽和细胞穿透肽。我们的目标是确定三种最有效的化合物，可以向前迈进，在一个项目中，通过完整的临床前开发进行临床试验。目前没有抗癌药物靶向这些细胞的膜。因此，MP1衍生肽的成功翻译将标志着在针对癌症的治疗武器库中的一类新的抗癌药物。特别是，我们还将测试肽与现有化疗药物联合使用的前景，并研究任何协同效应。

Organisms are well known to produce their own antibiotic host-defence peptides that act through damaging bacterial membranes due to their different molecular composition compared to the host organism's own cells. Some of these antimicrobial peptides are also known to have anticancer properties. One particularly promising anticancer peptide is polybia MP1 (MP1) from the venom of the Brazilian wasp Paulista Polybia.The mechanistic basis for the anticancer properties of these peptides bears similarities to their antimicrobial mode of action. Recently we showed that MP1's membrane disrupting effects were significantly amplified by two classes of lipid, PE and PS, which are present in much higher composition on the surface of cancer cells than the cells of normal tissue. Therefore, MP1 is a promising candidate peptide for development of a novel anticancer agent. This project will aim to optimise this peptide for potency and specificity to generate promising compounds for further clinical development.Through our current understanding of its interaction mechanism and how this relates to molecular structure, we will generate a set of MP1-derived peptides with predetermined single changes in amino acid composition. These peptides will be screened for activity against model membranes with compositions representative of cancer and normal cells as well as cancer and normal cell lines. Mutations that display enhanced potency or specificity compared to MP1 will be combined in a second round of designed peptides and activity screening. The most promising peptides from this screening phase will be taken forward for more detailed characterisation of their interactions with membranes and cells. We will use a novel approach that takes advantage of the different insights we can gain from systems of increasing complexity from minimal membrane models with simplified lipid mixtures representative of key compositional contents of the relevant cells, to membranes extracted from the relevant cells, to the cells themselves. This will allow unprecedented correlation between the detailed biophysical information obtained from model membranes to the complex biological response in whole cells. The lipid compositions of the cell lines will also be characterised, with particular interest in the compositions of membranes that are most sensitive to and those that are most resistant to peptide-induced membrane disruption.Application of highly sensitive surface analytical and optical microscopy techniques will provide detailed insight into the nature of peptide-membrane interactions. Importantly, beyond development of an anticancer peptide, this information will contribute valuable fundamental insight into the relationship between peptide structure, membrane composition and interaction mechanism that will be of use in the development of a wide range of membrane-active peptides, including antimicrobial peptides and cell penetrating peptides.We aim to identify the three most potent compounds that can be taken forward towards first-in-man clinical trials through full preclinical development in a project that will follow on from this one. No current anticancer drug targets the membrane of these cells. Therefore successful translation of an MP1-derived peptide would signal a new class of anticancer drug in the therapeutic arsenal against cancer. In particular we will also test the peptides' promise for use in combination with existing chemotherapeutics and investigate any synergistic effects.