STAT5/OLIG2 regulation of GBM therapeutic resistance and recurrence - Resubmit 3.22

STAT5/OLIG2 对 GBM 治疗耐药和复发的调节 - 重新提交 3.22

基本信息

批准号：
10583973
负责人：
SHWETAL MEHTA
金额：
$ 62.96万
依托单位：
MAYO CLINIC ARIZONA
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-02-21 至 2028-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10583973
关键词：
Affect Animals Brain Cell Line Cell model Cells Clinical Complex Data EGFR Gene Amplification EGFR gene Epidermal Growth Factor Receptor Exhibits Extracellular Domain Gene Amplification Genes Genetic Genetic Heterogeneity Glioblastoma Glioma Goals Heterogeneity Hot Spot Human Immunocompetent Infiltration Invaded JAK1 gene Malignant Neoplasms Mediating Modeling Molecular Mutation Oncogenic Patients Phosphorylation Point Mutation Property Protein Isoforms Receptor Protein-Tyrosine Kinases Recurrence Recurrent tumor Regimen Regulation Resistance Resistance profile Role Signal Pathway Signal Transduction Specimen Stat5 protein Testing Therapeutic Agents Therapeutic Intervention Treatment Efficacy Variant cancer cell clinically significant combinatorial dimer epidermal growth factor receptor VIII genetic manipulation genetic resistance in vivo Model knock-down mouse model mutant patient derived xenograft model response stem cell model stem cell self renewal stem cells stemness success targeted treatment temozolomide therapeutic target therapy resistant transcription factor tumor tumor progression upstream kinase

项目摘要

Project Summary Glioblastoma (GBM) is among the most lethal human cancers with extensive genetic and cellular heterogeneity. Genetic heterogeneity in GBM is seen through activation of multiple receptor tyrosine kinases (RTKs) including EGFR. Approximately ~50-60% of GBM tumors harbor amplification of the EGFR gene, including the constitutively active variant EGFRvIII, and point mutations within the extracellular domain of EGFR. Clinical effort at targeting EGFR itself has failed to increase survival, in part due to redundancy in the downstream signaling pathways triggered through EGFR or other oncogenic RTKs. Our data shows that EGFRvIII and possibly the hot spot mutations promote therapeutic resistance through downstream activation of oncogenic STAT5 signaling. Thus, understanding how STAT5 can serve as a point of convergence for oncogenic RTKs, such as EGFR will provide new opportunities for therapeutic interventions in GBM patients. One of the reasons why role of STAT5 signaling has been underappreciated in GBM is because long-term cultured GBM cells often lose EGFRvIII expression and do not show STAT5 activation. However, primary GBMs that retain EGFRvIII expression exhibit active STAT5 signaling. Our data indicate that EGFRvIII signaling activates STAT5 through JAK1/2- independent mechanisms and represents an attractive RTK model for understanding the role of STAT5 in GBM. We also find that therapy-resistant glioma stem cells (GSCs) that retain EGFRvIII expression also have increased STAT5 activation. In GSCs, EGFR participates in a feed-forward loop with a key cell fate and pro-mitogenic transcription factor, OLIG2. GSCs depleted of OLIG2 show decreased levels of phospho- STAT5 and expression of its downstream targets, (e.g. Fn14). Both STAT5 and OLIG2 function as dimers and in GSCs we find that STAT5 interacts with OLIG2. Furthermore, STAT5 inhibition decreases OLIG2- dependent GSC invasion. However, the upstream molecular mechanisms involved in OLIG2-dependent activation of STAT5 and signaling pathway(s) regulated by the OLIG2-STAT5 complex must be identified to effectively target the infiltrative and resistant glioma stem cells. We hypothesize that activation of STAT5-OLIG2 signaling mediated by oncogenic RTKs, such as EGFRvIII, promote increased invasion, therapy resistance, and stemness properties in GBM. Aim 1 will determine the mechanistic role of STAT5 isoform signaling in the context of EGFR variants in GBM cells. Aim 2 will determine the molecular mechanism(s) involved in OLIG2-mediated regulation of STAT5 activation in GSCs. Aim 3 will assess the functional and clinical significance of STAT5-OLIG2 signaling axis in GBM. Success of the proposal will identify, validate, and place into a clinically meaningful context the STAT5/OLIG2 signaling pathway as a therapeutic target for infiltrating cells that commonly underlie GBM fatality.

项目概要胶质母细胞瘤（GBM）是最致命的人类癌症之一，具有广泛的遗传和细胞异质性。 GBM 的遗传异质性可以通过多种受体酪氨酸激酶 (RTK) 的激活来观察，包括 EGFR。大约 50-60% 的 GBM 肿瘤存在 EGFR 基因扩增，包括组成型活性变体 EGFRvIII 以及 EGFR 胞外域内的点突变。临床努力靶向 EGFR 本身未能提高生存率，部分原因是下游信号传导存在冗余通过 EGFR 或其他致癌 RTK 触发的途径。我们的数据显示 EGFRvIII 以及可能的热点点突变通过下游致癌 STAT5 信号激活促进治疗耐药。因此，了解 STAT5 如何作为致癌 RTK（例如 EGFR）的汇聚点将为 GBM 患者的治疗干预提供了新的机会。 STAT5发挥作用的原因之一 GBM 中的信号传导一直被低估，因为长期培养的 GBM 细胞经常会丢失 EGFRvIII 表达并且不显示 STAT5 激活。然而，保留 EGFRvIII 表达的原发性 GBM 表现出活跃的 STAT5 信号传导。我们的数据表明 EGFRvIII 信号传导通过 JAK1/2 激活 STAT5- 独立的机制，并代表了一个有吸引力的 RTK 模型，用于理解 STAT5 在 GBM。我们还发现，保留 EGFRvIII 表达的耐药性神经胶质瘤干细胞 (GSC) 也 STAT5 激活增加。在 GSC 中，EGFR 参与具有关键细胞命运的前馈循环和促有丝分裂转录因子 OLIG2。耗尽 OLIG2 的 GSC 显示磷酸化水平降低 STAT5 及其下游靶标的表达（例如 Fn14）。 STAT5 和 OLIG2 均作为二聚体发挥作用在 GSC 中，我们发现 STAT5 与 OLIG2 相互作用。此外，STAT5 抑制会降低 OLIG2- 依赖性 GSC 侵袭。然而，OLIG2依赖的上游分子机制必须确定 STAT5 的激活以及 OLIG2-STAT5 复合物调节的信号通路有效靶向浸润性和耐药性胶质瘤干细胞。我们假设激活由致癌 RTK（例如 EGFRvIII）介导的 STAT5-OLIG2 信号传导可促进侵袭增加， GBM 的治疗抵抗性和干性特性。目标 1 将确定 STAT5 的机制作用 GBM 细胞中 EGFR 变异的同种型信号传导。目标 2 将确定分子参与 GSC 中 OLIG2 介导的 STAT5 激活调节的机制。目标 3 将评估 GBM 中 STAT5-OLIG2 信号轴的功能和临床意义。该提案的成功将识别、验证 STAT5/OLIG2 信号通路并将其置于具有临床意义的环境中通常导致 GBM 死亡的浸润细胞的治疗靶点。