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

• 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
• 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

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.

项目摘要 胶质母细胞瘤（GBM）是具有广泛遗传和细胞异质性的最致命的人类癌症之一。 通过激活多种受体酪氨酸激酶（RTK），可以看到GBM中的遗传异质性 egfr。大约〜50-60％的GBM肿瘤具有EGFR基因的扩增，包括 组成性活性变体EGFRVIII和EGFR细胞外域内的点突变。临床工作 针对EGFR本身的目标未能提高生存率，部分原因是下游信号的冗余 通过EGFR或其他致癌RTK触发的途径。我们的数据表明，egfrviii，可能是热 点突变通过致癌STAT5信号的下游激活促进治疗性抗性。 因此，了解STAT5如何用作致癌RTK的收敛点，例如EGFR 为GBM患者提供治疗干预措施的新机会。 STAT5角色的原因之一 信号传导在GBM中被低估了，因为长期培养的GBM细胞通常会失去EGFRVIII 表达，不显示STAT5激活。但是，保留EGFRVIII表达的主要GBM 展示活动的STAT5信号。我们的数据表明，EGFRVIII信号通过JAK1/2-激活STAT5。 独立的机制，代表了一个有吸引力的RTK模型，用于了解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） STAT5激活增加了。在GSC中，EGFR参与了具有钥匙单元命运的馈送回路 和促有丝分裂转录因子Olig2。寡聚2耗尽的GSC显示磷酸水平降低 STAT5及其下游目标的表达（例如FN14）。 STAT5和OLIG2都充当二聚体 在GSC中，我们发现STAT5与Olig2相互作用。此外，STAT5抑制降低了olig2- 依赖的GSC入侵。但是，涉及olig2依赖性的上游分子机制 必须识别由Olig2-Stat5复合物调节的STAT5和信号通路的激活 有效靶向浸润性和抗性神经胶质瘤干细胞。我们假设激活 由致癌RTK（例如EGFRVIII）介导的STAT5-OLIG2信号传导促进了侵袭，促进了增加的侵袭， GBM中的治疗耐药性和干性特性。 AIM 1将确定STAT5的机械作用 GBM细胞中EGFR变体的背景下的同工型信号传导。 AIM 2将确定分子 与GSC中STAT5激活的Olig2介导的调节有关的机制。 AIM 3将评估 GBM中STAT5-OLIG2信号轴的功能和临床意义。提案的成功将 识别，验证并将其置于临床上有意义的环境中 通常是GBM死亡基础的浸润细胞的治疗靶标。