背景:聚乙二醇化精氨酸脱亚胺酶(ADI-PEG20;聚乙二醇化亚胺酶)可消耗精氨酸并改善精氨酸琥珀酸合成酶1(ASS1)缺陷型恶性胸膜间皮瘤(MPM)患者的生存结果。优化基于ADI-PEG20的治疗将需要对耐药机制有更深入的了解。包括由肿瘤微环境介导的那些。这里,我们试图逆转ASS1缺陷型MPM复发患者肿瘤巨噬细胞浸润的增加。
方法:巨噬细胞-MPM肿瘤细胞系(2591,MSTO,通过流式细胞术分析用ADI-PEG20处理的JU77)共培养物。基因表达谱的微阵列实验在ADI-PEG20处理的MPM肿瘤细胞中进行,和巨噬细胞相关的遗传“命中”通过qPCR进行验证,ELISA,和LC/MS使用gegargiminaminase治疗的MPM患者的血浆进行细胞因子和精氨酸琥珀酸酯分析。
结果:我们鉴定表达ASS1的巨噬细胞促进ADI-PEG20处理的ASS1阴性MPM细胞系的活力。微阵列基因表达数据显示,在ADI-PEG20处理的MPM细胞系中,主要的CXCR2依赖性趋化特征和VEGF-A和IL-1α的共表达。我们证实巨噬细胞中的ASS1是IL-1α诱导型的,并且细胞上清液中的精氨酸琥珀酸盐浓度增加了一倍,足以在与ADI-PEG20共培养条件下恢复MPM细胞活力。为了进一步验证,我们检测到血浆VEGF-A和CXCR2依赖性细胞因子升高,在ADI-PEG20上,MPM进展患者的精氨酸琥珀酸增加。最后,脂质体氯膦酸盐耗尽ADI-PEG20驱动的巨噬细胞浸润,并在MSTO异种移植鼠模型中显著抑制生长。
结论:总的来说,我们的数据表明,ADI-PEG20可诱导的细胞因子通过巨噬细胞协调精氨酸琥珀酸促进ASS1缺陷型间皮瘤的作用.这种新的基质介导的抗性途径可用于优化间皮瘤和相关精氨酸依赖性癌症的精氨酸剥夺治疗。
BACKGROUND: Pegylated arginine deiminase (ADI-PEG20; pegargiminase) depletes arginine and improves survival outcomes for patients with argininosuccinate synthetase 1 (ASS1)-deficient malignant pleural mesothelioma (MPM). Optimisation of ADI-PEG20-based therapy will require a deeper understanding of resistance mechanisms, including those mediated by the tumor microenvironment. Here, we sought to reverse translate increased tumoral macrophage infiltration in patients with ASS1-deficient MPM relapsing on pegargiminase therapy.
METHODS: Macrophage-MPM tumor cell line (2591, MSTO, JU77) co-cultures treated with ADI-PEG20 were analyzed by flow cytometry. Microarray experiments of gene expression profiling were performed in ADI-PEG20-treated MPM tumor cells, and macrophage-relevant genetic \"hits\" were validated by qPCR, ELISA, and LC/MS. Cytokine and argininosuccinate analyses were performed using plasma from pegargiminase-treated patients with MPM.
RESULTS: We identified that ASS1-expressing macrophages promoted viability of ADI-PEG20-treated ASS1-negative MPM cell lines. Microarray gene expression data revealed a dominant CXCR2-dependent chemotactic signature and co-expression of VEGF-A and IL-1α in ADI-PEG20-treated MPM cell lines. We confirmed that ASS1 in macrophages was IL-1α-inducible and that the argininosuccinate concentration doubled in the cell supernatant sufficient to restore MPM cell viability under co-culture conditions with ADI-PEG20. For further validation, we detected elevated plasma VEGF-A and CXCR2-dependent cytokines, and increased argininosuccinate in patients with MPM progressing on ADI-PEG20. Finally, liposomal clodronate depleted ADI-PEG20-driven macrophage infiltration and suppressed growth significantly in the MSTO xenograft murine model.
CONCLUSIONS: Collectively, our data indicate that ADI-PEG20-inducible cytokines orchestrate argininosuccinate fuelling of ASS1-deficient mesothelioma by macrophages. This novel stromal-mediated resistance pathway may be leveraged to optimize arginine deprivation therapy for mesothelioma and related arginine-dependent cancers.