化学蛋白组学揭示免疫原性及肿瘤相关的细胞表面底物——外源激酶CK2α

Chemoproteomics reveals immunogenic and tumor-associated cell surface substrates of ectokinase CK2α

Cell Chemical Biology

影响因子:7.2

分区:生物学1区 Top / 生化与分子生物学2区

发表日期:2024 Sep 19

作者: Corleone S Delaveris, Sophie Kong, Jeff Glasgow, Rita P Loudermilk, Lisa L Kirkemo, Fangzhu Zhao, Fernando Salangsang, Paul Phojanakong, Juan Antonio Camara Serrano, Veronica Steri, James A Wells

DOI: 10.1016/j.chembiol.2024.07.018

摘要

外源性表位是免疫识别的基础，提供抗癌免疫的依据。鉴于肿瘤微环境中细胞外腺苷三磷酸（ATP）浓度较高，我们假设细胞外激酶（外源激酶）可能具有异常活性，在细胞表面蛋白上引入异常磷酸化位点。我们构建了细胞外激酶CK2α的细胞外连接型版本，证明其在肿瘤相关条件下具有活性，并通过化学蛋白组学流程分析其底物范围。实验中发现，免疫耐受的匹配肿瘤细胞经过表面高磷酸化处理后，能诱导小鼠产生多反应性抗血清。令人感兴趣的是，这些小鼠在应答抗原时产生B细胞和CD4+ T细胞反应，但未能引发CD8+ T细胞反应。该工作提供了一种探测细胞外磷酸化蛋白组的流程，显示即使在同源系统中，细胞外磷酸蛋白仍具有免疫原性。

Abstract

Foreign epitopes for immune recognition provide the basis of anticancer immunity. Due to the high concentration of extracellular adenosine triphosphate in the tumor microenvironment, we hypothesized that extracellular kinases (ectokinases) could have dysregulated activity and introduce aberrant phosphorylation sites on cell surface proteins. We engineered a cell-tethered version of the extracellular kinase CK2α, demonstrated it was active on cells under tumor-relevant conditions, and profiled its substrate scope using a chemoproteomic workflow. We then demonstrated that mice developed polyreactive antisera in response to syngeneic tumor cells that had been subjected to surface hyperphosphorylation with CK2α. Interestingly, these mice developed B cell and CD4+ T cell responses in response to these antigens but failed to develop a CD8+ T cell response. This work provides a workflow for probing the extracellular phosphoproteome and demonstrates that extracellular phosphoproteins are immunogenic even in a syngeneic system.