Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA.
Biomolecules. 2023 Aug 31;13(9):1335. doi: 10.3390/biom13091335.
High mobility group box 1 (HMGB1) is secreted from activated immune cells, necrotic cells, and certain cancers. Previous studies have reported that different patterns of post-translational modification, particularly acetylation and oxidation, mediate HMGB1 release and confer distinct extracellular HMGB1 signaling activity. Here we report that cisplatin but not carboplatin induces secretion of HMGB1 from human A549 non-small cell lung cancer (NSCLC) cells. Cisplatin-mediated HMGB1 secretion was dose-dependent and was regulated by nuclear exportin 1 (XPO1) also known as chromosomal maintenance 1 (CRM1) rather than adenosine diphosphate (ADP)-ribosylation, acetylation, or oxidation. HMGB1, as well as lysine acetylation and cysteine disulfide oxidation of secreted HMGB1, were monitored by sensitive and specific assays using immunoprecipitation, stable isotope dilution, differential alkylation, and nano liquid chromatography parallel reaction monitoring/high-resolution mass spectrometry (nano-LC-PRM/HRMS). A major fraction of the HMGB1 secreted by low-dose cisplatin treatment of A549 NSCLC cells was found to be in the fully reduced form. In contrast, mainly oxidized forms of HMGB1 were secreted by dimethyl sulfoxide (DMSO)-mediated apoptosis. These findings suggest that inhibition of XPO1 could potentiate the anti-tumor activity of cisplatin by increasing the nuclear accumulation of HMGB1 protein, an inhibitor of cisplatin DNA-adduct repair. Furthermore, low-dose cisplatin therapy could modulate the immune response in NSCLC through the established chemokine activity of extracellular reduced HMGB1. This could potentially enhance the efficacy of subsequent immunotherapy treatment.
高迁移率族蛋白 B1（HMGB1）可从活化的免疫细胞、坏死细胞和某些癌症中分泌。先前的研究报告表明，不同的翻译后修饰模式，特别是乙酰化和氧化，介导 HMGB1 的释放，并赋予独特的细胞外 HMGB1 信号转导活性。在这里，我们报告顺铂而非卡铂诱导人 A549 非小细胞肺癌（NSCLC）细胞分泌 HMGB1。顺铂介导的 HMGB1 分泌是剂量依赖性的，并且受核输出蛋白 1（XPO1）也称为染色体维持蛋白 1（CRM1）调节，而不是 ADP-核糖基化、乙酰化或氧化。HMGB1 以及分泌的 HMGB1 的赖氨酸乙酰化和半胱氨酸二硫键氧化，通过使用免疫沉淀、稳定同位素稀释、差异烷基化和纳米液相色谱平行反应监测/高分辨率质谱（nano-LC-PRM/HRMS）的灵敏和特异性测定来监测。在 A549 NSCLC 细胞用低剂量顺铂处理时分泌的 HMGB1 的主要部分被发现处于完全还原形式。相比之下，DMSO 介导的细胞凋亡主要以氧化形式分泌 HMGB1。这些发现表明，抑制 XPO1 可以通过增加 HMGB1 蛋白（顺铂 DNA 加合物修复的抑制剂）的核积累，增强顺铂的抗肿瘤活性。此外，低剂量顺铂治疗可以通过建立的细胞外还原 HMGB1 的趋化因子活性来调节 NSCLC 中的免疫反应。这可能会增强随后免疫治疗的疗效。
