Brain Tumour Research Centre, Bristol Medical School, University of Bristol, Bristol, UK.
IGFs & Metabolic Endocrinology Group, Bristol Medical School, Translational Health Sciences, University of Bristol, Southmead Hospital, Bristol, UK.
Cancer Med. 2023 Jul;12(13):14426-14439. doi: 10.1002/cam4.6071. Epub 2023 May 22.
The overall survival of IDH-wildtype glioblastoma patients is poor despite best available treatments. There is an urgent need for new biomarkers to inform more precise disease stratification. Previous studies have identified insulin-like growth factor binding protein-2 (IGFBP-2) as a potential biomarker for glioblastoma diagnosis and therapeutic targeting. Other studies have indicated links between the insulin-like growth factor (IGF) axis and tumorigenic functions of a molecular chaperone glucose related protein of 78 kDa (GRP78). We aimed to interrogate the oncogenic effects of IGFBP-2 and GRP78 in our glioma stem cell (GSC) lines and clinical cohort.
Immunoblotting, reverse transcription quantitative real-time PCR were used to quantify protein and mRNA levels derived from GSCs and non-malignant neural stem cells (NSCs). Microarray analysis was used to compare the differences in IGFBP-2 (IGFBP-2) and GRP78 (HSPA5) transcript expression between NSCs, GSCs and adult human cortex samples. Immunohistochemistry was used to quantify IGFBP-2 and GRP78 expression in IDH-wildtype glioblastoma tissue sections (n = 92) and clinical implications assessed using survival analysis. Finally, the relationship between IGFBP-2 and GRP78 was further explored molecularly using coimmunoprecipitation.
Here, we demonstrate that IGFBP-2 and HSPA5 mRNA is overexpressed in GSCs and NSCs in comparison to non-malignant brain tissue. We also determined a relationship in which G144 and G26 GSCs expressed higher IGFBP-2 protein and mRNA than GRP78, and this was reversed in mRNA isolated from adult human cortex samples. Clinical cohort analysis revealed that Glioblastomas with high IGFBP-2 protein expression paired with low GRP78 protein expression were significantly associated with a much shorter survival time (Median = 4 months, p = 0.019) compared with 12-14 months for any other combination of high/low protein expression.
Inverse levels of IGFBP-2 and GRP78 may be adverse clinical prognostic markers in IDH-wildtype glioblastoma. Further interrogation of the mechanistic link between IGFBP-2 and GRP78 may be important for rationalisation of their potential as biomarkers and therapeutic targets.
尽管采用了最佳治疗方法，IDH 野生型胶质母细胞瘤患者的总体生存率仍然很差。因此迫切需要新的生物标志物来更精确地进行疾病分层。先前的研究已经确定胰岛素样生长因子结合蛋白-2（IGFBP-2）是胶质母细胞瘤诊断和治疗靶点的潜在生物标志物。其他研究表明胰岛素样生长因子（IGF）轴与分子伴侣葡萄糖相关蛋白 78kDa（GRP78）的肿瘤发生功能之间存在联系。我们旨在研究 IGFBP-2 和 GRP78 在我们的神经胶质瘤干细胞（GSC）系和临床队列中的致癌作用。
使用免疫印迹和逆转录定量实时 PCR 来定量源自 GSCs 和非恶性神经干细胞（NSCs）的蛋白质和 mRNA 水平。微阵列分析用于比较 NSCs、GSCs 和成人人类皮质样本中 IGFBP-2（IGFBP-2）和 GRP78（HSPA5）转录表达的差异。免疫组织化学用于量化 IDH 野生型胶质母细胞瘤组织切片中的 IGFBP-2 和 GRP78 表达（n = 92），并使用生存分析评估临床意义。最后，使用共免疫沉淀进一步探索了 IGFBP-2 和 GRP78 之间的分子关系。
在这里，我们证明与非恶性脑组织相比，IGFBP-2 和 HSPA5 mRNA 在 GSCs 和 NSCs 中过度表达。我们还确定了一种关系，其中 G144 和 G26 GSCs 表达的 IGFBP-2 蛋白和 mRNA 高于 GRP78，而从成人人类皮质样本中分离的 mRNA 则相反。临床队列分析表明，高 IGFBP-2 蛋白表达与低 GRP78 蛋白表达相关的胶质母细胞瘤与任何其他高/低蛋白表达组合相比，存活时间明显更短（中位= 4 个月，p = 0.019）。
IGFBP-2 和 GRP78 的水平可能是 IDH 野生型胶质母细胞瘤的不利临床预后标志物。进一步研究 IGFBP-2 和 GRP78 之间的机制联系对于合理化它们作为生物标志物和治疗靶点的潜力可能很重要。
