胶质母细胞瘤（GBM）是浸润性恶性脑肿瘤，大多数在手术切除和放化疗后一年内复发。对放化疗后胶质母细胞瘤细胞的研究已被证明可诱导转分化、细胞可塑性、DNA 损伤反应的激活和干性。由于胶质母细胞瘤是一种异质性肿瘤，会产生治疗耐药性和可塑性，因此我们研究了复发肿瘤中是否存在全基因组 DNA 甲基化变化。利用全基因组 DNA 甲基化芯片，我们比较了 11 种原发性（首次出现）肿瘤与13 复发性（复发性）GBM，以描绘与治疗暴露、治疗抵抗和疾病复发相关的表观遗传变化的贡献。我们的数据显示，与原发性疾病相比，复发性胶质母细胞瘤中有 1,224 个高甲基化探针和 526 个低甲基化探针。我们发现溶质载体和离子通道基因、白细胞介素受体/配体基因、肿瘤抑制基因和与转移相关的基因的差异甲基化。我们对这样一个低甲基化上调基因进行了功能性表征，即炭疽毒素受体 1/肿瘤内皮标志物 8 (ANTXR1/TEM8)，与原发性肿瘤相比，其表达被证实在复发性胶质母细胞瘤中显着上调，并通过免疫组织化学证实。通过过表达和敲低方法，我们发现 TEM8 诱导胶质母细胞瘤细胞的增殖、侵袭、迁移和化疗放射抗性。此外，我们还证明了由于 TEM8 通过 Src/PI3K/AKT/GSK3β/β-catenin 通路过度表达而导致 β-catenin 稳定和激活 β-catenin 转录程序的新机制。我们报告了复发性乳腺癌中全基因组 DNA 甲基化的变化GBM 并提示 TEM8 基因参与 GBM 复发和进展。版权所有 © 2024，国际抗癌研究所（George J. Delinasios 博士），保留所有权利。

Glioblastomas (GBM) are infiltrative malignant brain tumors which mostly recur within a year's time following surgical resection and chemo-radiation therapy. Studies on glioblastoma cells following radio-chemotherapy, have been demonstrated to induce trans-differentiation, cellular plasticity, activation of DNA damage response and stemness. As glioblastomas are heterogenous tumors that develop treatment resistance and plasticity, we investigated if there exist genome-wide DNA methylation changes in recurrent tumors.Utilizing genome-wide DNA methylation arrays, we compared the DNA methylation profile of 11 primary (first occurrence) tumors with 13 recurrent (relapsed) GBM, to delineate the contribution of epigenetic changes associated with therapy exposure, therapy resistance, and relapse of disease.Our data revealed 1,224 hypermethylated- and 526 hypomethylated-probes in recurrent glioblastomas compared to primary disease. We found differential methylation of solute carrier and ion channel genes, interleukin receptor/ligand genes, tumor-suppressor genes and genes associated with metastasis. We functionally characterized one such hypomethylated-up-regulated gene, namely anthrax toxin receptor 1/tumor endothelial marker 8 (ANTXR1/TEM8), whose expression was validated to be significantly up-regulated in recurrent glioblastomas compared to primary tumors and confirmed by immunohistochemistry. Using overexpression and knockdown approaches, we showed that TEM8 induces proliferation, invasion, migration, and chemo-radioresistance in glioblastoma cells. Additionally, we demonstrated a novel mechanism of β-catenin stabilization and activation of the β-catenin transcriptional program due to TEM8 overexpression via a Src/PI3K/AKT/GSK3β/β-catenin pathway.We report genome-wide DNA methylation changes in recurrent GBM and suggest involvement of the TEM8 gene in GBM recurrence and progression.Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.