Vadakekolathu Jayakumar, Boocock David J, Pandey Kirti, Guinn Barbara-Ann, Legrand Antoine, Miles Amanda K, Coveney Clare, Ayala Rochelle, Purcell Anthony W, McArdle Stephanie E
John van Geest Cancer Research Centre, Nottingham Trent University, Nottingham NG11 8NS, UK.
Centre for Health, Ageing and Understanding Disease, School of Science and Technology, Nottingham Trent University, Nottingham NG1 4FQ, UK.
Cancers (Basel). 2022 Aug 17;14(16):3975. doi: 10.3390/cancers14163975.
The p53 protein is mutated in more than 50% of human cancers. Mutated p53 proteins not only lose their normal function but often acquire novel oncogenic functions, a phenomenon termed mutant p53 gain-of-function. Mutant p53 has been shown to affect the transcription of a range of genes, as well as protein-protein interactions with transcription factors and other effectors; however, no one has intensively investigated and identified these proteins, or their MHC presented epitopes, from the viewpoint of their ability to act as targets for immunotherapeutic interventions. We investigated the molecular changes that occurred after the null osteosarcoma cells, SaOS-2, were transfected with one of two conformational p53-mutants, either R175H or R273H. We then examined the phenotypic and functional changes using macroscopic observations, proliferation, gene expression and proteomics alongside immunopeptidome profiling of peptide antigen presentation in the context of major histocompatibility complex (MHC) class I molecules. We identified several candidate proteins in both mutant cell lines with differential expression when compared to the null vector control, SaOS-V. Quantitative SWATH proteomics combined with immune-peptidome analysis of the class-I eluted peptides identified several epitopes presented on pMHC and in silico analysis shortlisted which antigens were expressed in a range of cancerous but not adjacent healthy tissues. Out of all the candidates, KLC1 and TOP2A showed high levels of expression in every tumor type examined. From these proteins, three A2 and four pan HLA-A epitopes were identified in both R175H and R273H from TOP2A. We have now provided a short list of future immunotherapy targets for the treatment of cancers harboring mutated .
超过50%的人类癌症中存在p53蛋白突变。突变的p53蛋白不仅失去其正常功能，还常常获得新的致癌功能，这种现象被称为突变型p53功能获得。已表明突变型p53会影响一系列基因的转录，以及与转录因子和其他效应器的蛋白质-蛋白质相互作用；然而，从它们作为免疫治疗干预靶点的能力角度，没有人深入研究和鉴定这些蛋白质或其MHC呈递的表位。我们研究了骨肉瘤空细胞系SaOS-2用两种构象的p53突变体之一（R175H或R273H）转染后发生的分子变化。然后，我们通过宏观观察、增殖、基因表达和蛋白质组学以及在主要组织相容性复合体（MHC）I类分子背景下的肽抗原呈递免疫肽组分析，来检测表型和功能变化。与空载体对照SaOS-V相比，我们在两种突变细胞系中都鉴定出了几种差异表达的候选蛋白。定量SWATH蛋白质组学结合I类洗脱肽的免疫肽组分析，鉴定出了pMHC上呈递的几种表位，并且通过计算机分析筛选出了在一系列癌组织而非相邻健康组织中表达的抗原。在所有候选蛋白中，KLC1和TOP2A在所检测的每种肿瘤类型中都显示出高表达水平。从这些蛋白中，在TOP2A的R175H和R273H中都鉴定出了三个A2和四个泛HLA-A表位。我们现在已经提供了一份用于治疗携带p53突变癌症的未来免疫治疗靶点的简短清单。
