突破免疫治疗耐药：GBP2 相分离驱动铁死亡，为黑色素瘤治疗赋能

2025 年 12 月，《Nature Communications》发表的一项重磅研究揭示了 GBP2 在黑色素瘤免疫治疗中的关键调控机制。该研究由武汉大学中南医院团队完成，全程使用爱必信（absin）#abs955 GBP2 抗体，为机制验证提供了核心工具支撑，为克服 PD-L1 免疫治疗耐药提供了全新靶点与策略。

文献标题：GBP2 condensates promote ferroptosis to sensitize anti-PD-L1 immunotherapy in melanoma

发表期刊：Nature Communications (IF=15.7)

DOI：https://doi.org/10.1038/s41467-025-67690-9

使用 Absin 产品：免疫(共)沉淀(IP/CoIP)试剂盒（货号：abs955）

一、研究背景：免疫治疗耐药的未解难题

免疫检查点阻断（ICB）疗法（如抗 PD-L1 抗体）已成为黑色素瘤治疗的核心手段，但超过 50% 患者会出现原发或获得性耐药。其核心瓶颈在于肿瘤微环境（TME）的免疫抑制状态，尤其是干扰素 -γ（IFN-γ）信号通路受损，导致 CD8?T 细胞杀伤功能减弱。

近年研究发现，铁死亡（ferroptosis） 可增强肿瘤免疫原性，与 ICB 具有显著协同效应。但 IFN-γ 如何调控铁死亡、能否通过靶向该通路逆转耐药，仍缺乏清晰机制。本研究以此为切入点，聚焦 IFN-γ 诱导的关键分子 GBP2，探索其在 “铁死亡 - 免疫激活” 轴中的作用。

二、研究思路：从大数据到机制的精准锁定

研究团队采用 “生信筛选 + 体内外验证 + 机制深挖 + 临床关联” 的递进式思路，层层破解 GBP2 的功能：

1. WGCNA 生信筛选：分析黑色素瘤队列，锁定与 IFN-γ 应答、CTL 杀伤活性高度相关的GBP2 基因；
2. 临床样本验证：证实 GBP2 高表达与患者良好预后、ICB 应答率正相关；
3. 体内外功能实验：构建 GBP2 敲除 / 过表达细胞系与动物模型，验证其对铁死亡和 ICB 疗效的调控作用；
4. 机制解析：聚焦 GBP2 相分离，明确其通过 “GBP2-SHP1-STAT1-SLC7A11” 轴调控铁死亡；
5. 临床转化：验证 GBP2/ SLC7A11 可作为 ICB 疗效预测标志物。

三、核心研究成果：GBP2—— 免疫治疗的 “黄金靶点”

1. GBP2 是 IFN-γ 驱动铁死亡的关键放大器

研究证实，GBP2 是IFN-γ 诱导的核心功能分子，可显著增强 CD8?T 细胞介导的铁死亡。

? 体外实验：GBP2 过表达显著升高脂质 ROS（铁死亡标志物），敲除则完全逆转该效应（对应原文图 2G、2H）；
? 体内实验：GBP2 过表达联合抗 PD-L1 可显著抑制肿瘤生长，敲除则疗效丧失（对应原文图 2C、2D）。

Fig2 Knockout of GBP2 blunted the efficacy of ICB and inhibited the CTL-induced ferroptosis.

A Tumor growth in mice subcutaneously injected with sgCtrl or GBP2?/? B16-OVA cells and treated with OT 1 T cells or PBS every 7 days. B Tumor inhibition rate of GBP2?/? relative to sgCtrl tumors under OT-1 treatment (n?=?6). C Tumor growth in mice bearing sgCtrl or GBP2?/?B16-OVA tumors treated with anti–PD L1 (200?μg/mouse) or IgG every 3 days. D Tumor inhibition rate of GBP2?/? versus sgCtrl tumors following anti–PD-L1 treatment (n?=?6). E Control or GBP2-overexpressing tumor cells were co-cultured with OT-1 cells (E:T?=?1:1, 24?h) with or without emricasan (20?μM), ferrostatin-1 (Fer-1, 10?μM), necrostatin-1 (Nec-1, 20?μM), or disulfiram (20?μM) (n?=?3). F GSEA of ferroptosis between high- and low-GBP2 patients according to the SKCM cohort. Lipid ROS in B16-OVA tumors treated with OT-1 (G) or anti–PD-L1 (H), quantified in CD45? cells by flow cytometry. Representative lipid ROS images (I) and viability (J) of Vec or GBP2oe B16-OVA cells co-cultured with OT-1 (E:T?=?5:1, 24?h), followed by Fer-1 (10?μM) for 24?h. K IFN-γ levels in tumor lysates from anti–PD-L1 or IgG-treated mice measured by ELISA. L Viability of Vec or GBP2oe cells after co-culture (24?h, E:T?=?1:1) with OT-1 T cells transduced with sgCtrl, sgIFNγ, sgTNFα, or sgPRF1 (n?=?3). M Vec or GBP2oe B16-OVA cells were subcutaneously implanted into C57BL/6 mice. When tumors reached ~125?mm3, both Vec and GBP2oe groups were respectively treated with either anti-IFN-γ or control IgG antibodies every 3 days. Tumor-bearing mice from both groups received anti-PD-L1 therapy every 3 days. All p value?<?0.05 as statistic difference. n?=?3 independent experiments (E, J, L); n?=?6 independent experiments (A–D, G–I, K, M). The data are represented as mean?±?SD. p value by unpaired two-tailed t-test (B, D, G, H) or one-way ANOVA (I–K) or two-way ANOVA (A, C, E, L, M) or two-sided permutation test (F). Source data are provided as a Source Data file.

2. GBP2 通过相分离 “扣押” SHP1，激活 STAT1 通路

这是本研究最突破性的发现：IFN-γ 诱导 GBP2 发生液 - 液相分离（LLPS），形成动态凝聚体。

? 机制：GBP2 通过其无序区（IDR，aa436-579）形成凝聚体，特异性结合并扣押磷酸酶 SHP1，阻止 SHP1 去磷酸化 STAT1；
? 效应：持续激活的 STAT1 抑制铁死亡抑制蛋白 SLC7A11 转录，触发铁死亡（对应原文图 4、5）；
? 验证：删除 GBP2 的 IDR 区域，凝聚体无法形成，SHP1 不能被扣押，STAT1 激活受阻，铁死亡完全抑制（对应原文图 5K、5L）。

Fig5 GBP2 sequesters SHP1 via IDR-mediated phase separation to augment ferroptosis.

A B16-OVA cells treated with IFN-γ (10?ng/mL, 12?h) were immunoprecipitated with anti-GBP2 for mass spectrometry (MS); SHP1 was selected. B IP assay shows endogenous GBP2 interact with SHP1 in B16-OVA and A375 cells. C sgCtrl and GBP2?/? of B16-OVA and A375 cells were treated with IFN-γ (10?ng/mL, 12?h), followed by SHP1 knockdown using siRNA for 24?h; cell lysates were analyzed by western blot. D Representative live-cell imaging of B16-OVA cells expressing GBP2-mCherry stimulated with 10?ng/ml IFN-γ for 6?h, and transfected with SHP1-mEGFP plasmid for 36?h. The line plots show GBP2-mCherry and SHP1-mEGFP colocalization of areas. E Western blot analysis of B16-OVA GBP2?/? and A375 GBP2?/? cells treated with 10?ng/ml IFN-γ for 12?h, followed by transfection with vector, GBP2-FL, or GBP2 ΔIDR plasmids for 24?h. F, G Representative live-cell imaging and high-resolution confocal demonstrated colocalization of GBP2-mCherry with SHP1-mEGFP, but not GBP2ΔIDR, upon IFN-γ stimulation. H In vitro kinase assays revealed enhanced STAT1 phosphorylation in the presence of GBP2 condensates. I, J In vitro phase separation assays compared condensate formation between GBP2-WT, GBP2ΔIDR, and GBP2-MBP, confirming IDR-dependent condensate activity and STAT1 phosphorylation enhancement. K GBP2?/? B16-OVA cells expressing GBP2-FL or GBP2ΔIDR (1?×?106) were subcutaneously injected into C57BL/6 mice and treated with anti–PD-L1 antibody (200?μg/mouse) or IgG every 3 days. L Lipid ROS in CD45? tumor cells were quantified by flow cytometry. M Tumors from GBP2-FL and GBP2ΔIDR groups were immunoprecipitated with anti-SHP1 and analyzed by western blot. N Representative immunofluorescence images of GBP2 in GBP2-FL and GBP2ΔIDR tumors treated with anti–PD-L1 (n?=?3). All p value?<?0.05 as statistic difference. n?=?3 independent experiments (B–J, M, N); n?=?6 independent experiments (K, L). The data are represented as mean?±?SD. p value by unpaired two-tailed t-test (L) or two-way ANOVA (K). Source data are provided as a Source Data file.

3. GBP2 增强肿瘤免疫原性，促进 CD8?T 细胞浸润

铁死亡的肿瘤细胞释放HMGB1等损伤相关分子（DAMPs），促进树突状细胞（DC）成熟，增强 CD8?T 细胞浸润与活化。

? GBP2 高表达肿瘤中 CD8?T 细胞浸润显著增加（对应原文图 6G）；
? 临床样本证实：GBP2 高表达患者肿瘤组织中 CD8?T 细胞浸润水平更高，预后更好（对应原文图 7I）。

4. GBP2 可作为 ICB 疗效预测标志物

多中心临床队列验证：

? GBP2 高表达 + SLC7A11 低表达的黑色素瘤患者，抗 PD-L1 治疗应答率最高、生存期最长（对应原文图 7D、7F）；
? 该标志物在肺癌、尿路上皮癌中同样具有预测价值。

Fig7 GBP2 acts as an immunotherapeutic target in patients with cancer.

A Box plots showing expression of ICB response-related signatures between high and low GBP2 group in the SKCM cohort (n?=?470). IMPRES: Minimum (high vs. low: 0.064 vs. 0.001); Median (high vs. low: 0.668 vs. 0.332); Maximum (high vs. low: 1.0 vs. 0.751). IPRES: Minimum (high vs. low: 0.0 vs. 0.0); Median (high vs. low: 0.57 vs. 0.419); Maximum (high vs. low: 1.0 vs. 1.0). T cell-inflam GEP: Minimum (high vs. low: 0.047 vs. 0.0); Median (high vs. low: 0.707 vs. 0.316); Maximum (high vs. low: 0.941 vs. 0.732). B Submap analysis demonstrates high GBP2 group in SKCM samples closely align with the PD1-response (PD1-R) group defined in the melanoma cohort. C Treatment response rates to anti-PD-1 or combination immunotherapy in pre-therapy (PRE) patients stratified in high or low GBP2 expression groups. SD stable disease, PD progressive disease, CR complete response, PR partial response. D PRE patients were stratified into three groups based on SLC7A11 and GBP2 expression, with corresponding immunotherapy response rates shown. Kaplan–Meier survival analysis for GBP2-high vs. -low groups (E), and for the three SLC7A11/GBP2-based groups (F). G Spatial transcriptomics of two hepatocellular carcinoma sections (one responder, one non-responder) identified morphology-aligned clusters, annotated as malignant, boundary, or non-malignant regions. H The spatial feature plot that visualizes the proportion of the CD8+T cells and spatial expression patterns of GBP2 and SLC7A11 in spatial spots (n?=?2). I The tissue sections from 12 patients with melanoma were immunohistochemically stained with anti-GBP2 or anti-SLC7A11 antibody. The correlation between the expression of GBP2 and SLC7A11 is shown (right). Scale bars, 200?μm. All p value?<?0.05 as statistic difference. p value by unpaired two-tailed Wilcoxon test (A) or two-sided permutation test (B) or Pearson’s chi-square test (D) or Log-rank test (E, F) or the correlation coefficient and two-tailed p value were calculated using Pearson’s correlation analysis (I). Source data are provided as a Source Data file.

四、爱必信（absin）#abs955 抗体：研究的核心工具

本研究全程使用爱必信（absin）#abs955 GBP2 抗体，支撑了从分子机制到临床验证的全链条实验，其高特异性、高灵敏度成为关键保障。

1. 核心应用场景（对应原文图片）

? Western Blot（WB）：精准检测细胞 / 组织中 GBP2 表达及 STAT1、SLC7A11 等通路蛋白变化（对应原文图 3G、5E）；
? 免疫荧光（IF）：清晰显示 GBP2 在细胞内的凝聚体结构及与 SHP1 的共定位（对应原文图 4B、5D）；

? 免疫组化（IHC）：验证临床样本中 GBP2 表达水平及与 CD8?T 细胞的空间分布（对应原文图 7I）；

? 免疫共沉淀（Co-IP）：证实 GBP2 与 SHP1 的直接相互作用（对应原文图 5B）。

2. 产品核心优势

? 高特异性：仅识别天然 / 重组 GBP2，无交叉反应，保障机制结论可靠性；
? 多应用兼容：适配 WB、IF、IHC、Co-IP 等多种实验，满足多维度验证需求；
? 性能稳定：批次间一致性强，助力体内外实验重复性与可靠性。

五、研究意义与转化价值

1. 机制创新：首次揭示GBP2 相分离是连接 IFN-γ、铁死亡与肿瘤免疫的核心桥梁，填补了免疫治疗耐药机制的空白；
2. 靶点价值：GBP2 可作为黑色素瘤联合免疫治疗的全新靶点，通过靶向 GBP2 相分离，逆转 ICB 耐药；
3. 临床应用：GBP2/SLC7A 表达谱可作为 ICB 疗效预测标志物，指导精准用药；
4. 工具认可：爱必信 #abs955 GBP2 抗体在顶级研究中的成功应用，印证了其在生命科学研究中的可靠性与权威性。