N6-甲基腺苷修饰的假基因 HSPA7 与肿瘤微环境相关，并预测胶质母细胞瘤对免疫检查点治疗的反应。

BACKGROUND: Glioblastoma (GBM), one of the most aggressive tumors of the brain, has no effective or sufficient therapies. Identifying robust biomarkers for the response to immune checkpoint blockade (ICB) therapy, a promising treatment option for GBM patients, is urgently needed. METHODS: We comprehensively evaluated lncRNA mA modification patterns in mA-sequencing (mA-seq) data for GBM tissues and systematically investigated the immune and stromal regulators of these mA-regulated lncRNAs. We used the single-sample gene-set enrichment analysis (ssGSEA) algorithm to investigate the difference in enriched tumor microenvironment (TME) infiltrating cells and the functional annotation of HSPA7 in individual GBM samples. Further, we validated that HSPA7 promoted the recruitment of macrophages into GBM TME , as well as in our GBM tissue section. We also explored its impact on the efficacy of ICB therapy using the patient-derived glioblastoma organoid (GBO) model. RESULTS: Here, we depicted the first transcriptome-wide mA methylation profile of lncRNAs in GBM, revealing highly distinct lncRNA mA modification patterns compared to those in normal brain tissues. We identified the mA-modified pseudogene HSPA7 as a novel prognostic risk factor in GBM patients, with crucial roles in immunophenotype determination, stromal activation, and carcinogenic pathway activation. We confirmed that HSPA7 promoted macrophage infiltration and SPP1 expression upregulating the YAP1 and LOX expression of glioblastoma stem cells (GSCs) and in our clinical GBM tumor samples. We also confirmed that knockdown of HSPA7 might increase the efficiency of anti-PD1 therapy utilizing the GBO model, highlighting its potential as a novel target for immunotherapy. CONCLUSIONS: Our results indicated that HSPA7 could be a novel immunotherapy target for GBM patients.

背景：胶质母细胞瘤（GBM）是最具侵袭性的脑肿瘤之一，目前尚无有效的治疗方法。因此，迫切需要确定免疫检查点阻断（ICB）治疗反应的稳健生物标志物，ICB 治疗是 GBM 患者的一种很有前途的治疗选择。

方法：我们全面评估了 GBM 组织中 mA 测序（mA-seq）数据中的 lncRNA mA 修饰模式，并系统研究了这些 mA 调控的 lncRNA 的免疫和基质调节剂。我们使用单样本基因集富集分析（ssGSEA）算法来研究单个 GBM 样本中富含肿瘤微环境（TME）浸润细胞的差异和 HSPA7 的功能注释。此外，我们验证了 HSPA7 促进了巨噬细胞在 GBM TME 中的募集，以及在我们的 GBM 组织切片中的募集。我们还使用患者来源的胶质母细胞瘤类器官（GBO）模型探索了其对 ICB 治疗效果的影响。

结果：在这里，我们描绘了 GBM 中 lncRNA 的首个转录组范围的 mA 甲基化图谱，与正常脑组织相比，lncRNA 的 mA 修饰模式存在高度差异。我们确定了 mA 修饰的假基因 HSPA7 是 GBM 患者的一个新的预后风险因素，它在免疫表型确定、基质激活和致癌途径激活中起着关键作用。我们证实 HSPA7 促进了巨噬细胞的浸润和 SPP1 的表达上调，从而上调了 GSCs 中的 YAP1 和 LOX 表达，并且在我们的临床 GBM 肿瘤样本中也是如此。我们还证实，利用 GBO 模型敲低 HSPA7 可能会提高抗 PD1 治疗的效率，这凸显了其作为免疫治疗新靶点的潜力。

结论：我们的研究结果表明，HSPA7 可能是 GBM 患者的一种新的免疫治疗靶点。