免疫检查点疗法（ICT）为特定癌症患者提供了持久的反应，但耐药性仍然是一个重大挑战，促使人们探索潜在的分子机制。酪氨酰蛋白磺基转移酶-2 (TPST2)以其在蛋白质酪氨酸O-硫酸化中的作用而闻名，已被认为可以调节细胞外蛋白质-蛋白质相互作用，但其在癌症免疫中的具体作用仍然很大程度上尚未被探索。探索影响肿瘤细胞内在因素为了提高抗 PD1 反应性，我们对植入人类免疫细胞的人源化小鼠进行了功能丧失遗传筛查。通过评估 IFNγ 介导的靶基因诱导、STAT1 磷酸化、HLA 表达和细胞生长抑制来评估癌细胞对干扰素 γ (IFNγ) 的反应性。通过免疫共沉淀和质谱鉴定了 TPST2 的磺基酪氨酸修饰的靶基因。使用小鼠同基因肿瘤模型评估了 TPST2 抑制的体内效果，并通过批量和单细胞 RNA 测序分析进行了证实。通过体内全基因组 CRISPR 筛选，TPST2 功能丧失成为抗 PD1 的潜在增强剂治疗效果。 TPST2 通过在 Y397 残基处硫酸化 IFNγ 受体 1 来抑制 IFNγ 信号传导，而其下调则增强 IFNγ 介导的信号传导和抗原呈递。癌细胞中 TPST2 的缺失通过增强肿瘤浸润淋巴细胞来增强同基因小鼠肿瘤模型中的抗 PD1 抗体功效。 RNA测序数据显示TPST2与抗原呈递呈负相关，并且TPST2表达增加与癌症类型的不良预后和癌症免疫改变相关。我们提出TPST2作为癌症免疫抑制剂的新作用，并主张将其考虑作为ICT的治疗靶点基于治疗。© 2024。作者。

Immune checkpoint therapy (ICT) provides durable responses in select cancer patients, yet resistance remains a significant challenge, prompting the exploration of underlying molecular mechanisms. Tyrosylprotein sulfotransferase-2 (TPST2), known for its role in protein tyrosine O-sulfation, has been suggested to modulate the extracellular protein-protein interactions, but its specific role in cancer immunity remains largely unexplored.To explore tumor cell-intrinsic factors influencing anti-PD1 responsiveness, we conducted a pooled loss-of-function genetic screen in humanized mice engrafted with human immune cells. The responsiveness of cancer cells to interferon-γ (IFNγ) was estimated by evaluating IFNγ-mediated induction of target genes, STAT1 phosphorylation, HLA expression, and cell growth suppression. The sulfotyrosine-modified target gene of TPST2 was identified by co-immunoprecipitation and mass spectrometry. The in vivo effects of TPST2 inhibition were evaluated using mouse syngeneic tumor models and corroborated by bulk and single-cell RNA sequencing analyses.Through in vivo genome-wide CRISPR screening, TPST2 loss-of-function emerged as a potential enhancer of anti-PD1 treatment efficacy. TPST2 suppressed IFNγ signaling by sulfating IFNγ receptor 1 at Y397 residue, while its downregulation boosted IFNγ-mediated signaling and antigen presentation. Depletion of TPST2 in cancer cells augmented anti-PD1 antibody efficacy in syngeneic mouse tumor models by enhancing tumor-infiltrating lymphocytes. RNA sequencing data revealed TPST2's inverse correlation with antigen presentation, and increased TPST2 expression is associated with poor prognosis and altered cancer immunity across cancer types.We propose TPST2's novel role as a suppressor of cancer immunity and advocate for its consideration as a therapeutic target in ICT-based treatments.© 2024. The Author(s).