ROR1 Facilitates Glioblastoma Growth via Stabilizing GRB2 to Promote c-fos Expression in Glioma Stem Cells
Academic Background
Glioblastoma (GBM) is the most common and aggressive primary brain tumor, with significant treatment challenges and a poor prognosis. Despite advancements in surgery, chemotherapy, and radiotherapy, the 5-year survival rate for GBM patients remains below 4%. The recurrence and therapeutic resistance of GBM are primarily attributed to the presence of glioma stem cells (GSCs). GSCs possess self-renewal, sustained proliferation, and multilineage differentiation capabilities, making them a key factor in GBM recurrence and treatment resistance. Therefore, targeting GSCs has become a critical direction in GBM research.
ROR1 (Receptor Tyrosine Kinase-Like Orphan Receptor 1) is a receptor tyrosine kinase-like orphan receptor that is highly expressed in various tumors but exhibits very low expression in normal tissues. Studies have shown that ROR1 plays a significant role in the maintenance of cancer stem cells (CSCs) and tumor progression. However, the expression characteristics of ROR1 in GBM and its specific mechanisms in GSCs remain unclear. This study aims to elucidate the role of ROR1 in GSCs and explore its potential as a therapeutic target for GBM.
Source of the Paper
This paper was completed by a research team from Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, with primary authors including Hongtao Zhu and Lidong Cheng, among others. The paper was published in Neuro-Oncology in 2025, titled “ROR1 facilitates glioblastoma growth via stabilizing GRB2 to promote c-fos expression in glioma stem cells.”
Research Process and Results
1. Expression Characteristics of ROR1 in GBM and GSCs
The study first assessed the expression characteristics of ROR1 in GBM and GSCs through bioinformatic analysis, patient specimens, and patient-derived GSCs. The results showed that ROR1 is significantly upregulated in GBM and preferentially expressed in GSCs. Further immunohistochemical (IHC) and immunofluorescence (IF) staining confirmed that ROR1 expression is positively correlated with GSC markers such as CD133 and CD15.
2. Impact of ROR1 on GSC Proliferation and Self-Renewal
Using lentivirus-mediated gene knockdown and overexpression experiments, the study evaluated the effects of ROR1 on GSC proliferation and self-renewal. The results demonstrated that ROR1 knockdown significantly inhibited GSC proliferation and self-renewal, while ROR1 overexpression promoted these processes. Additionally, ROR1 knockdown increased the expression of apoptosis markers (e.g., cleaved PARP and cleaved caspase3) and reduced the expression of stem cell markers (e.g., SOX2).
3. Regulation of the GRB2/ERK/c-Fos Signaling Pathway by ROR1
Through RNA sequencing (RNA-seq) and immunoblot analysis, the study revealed that ROR1 activates the ERK/c-Fos signaling pathway by stabilizing GRB2. ROR1 directly binds to GRB2, reducing its lysosomal degradation and thereby promoting the activation of the downstream ERK/c-Fos signaling pathway. Overexpression of c-Fos partially reversed the inhibitory effects of ROR1 knockdown on GSC proliferation and self-renewal.
4. Clinical Significance of the ROR1-GRB2-c-Fos Axis in GBM Patients
Using multivariate Cox regression analysis and gene set enrichment analysis (GSEA), the study validated the activation of the ROR1-GRB2-c-Fos axis in GBM patients and its correlation with GSC markers. The results showed that the expression levels of ROR1, GRB2, and c-Fos were significantly associated with poor prognosis in GBM patients.
Conclusions and Significance
This study elucidates the critical role of ROR1 in GSCs and its mechanism of promoting GBM progression through the GRB2/ERK/c-Fos signaling pathway. ROR1 stabilizes GRB2 by binding to it, reducing its lysosomal degradation, and thereby activating the downstream ERK/c-Fos signaling pathway, which promotes GSC proliferation and self-renewal. Overexpression of c-Fos reversed the inhibitory effects of ROR1 knockdown on GSCs, further validating the importance of this signaling axis.
Scientific and Application Value
The scientific value of this study lies in its first-time revelation of the regulatory mechanism of the ROR1-GRB2-c-Fos axis in GSCs, providing new theoretical foundations for GBM treatment. ROR1, as a potential therapeutic target for GBM, exhibits high specificity due to its low expression in normal tissues. Additionally, c-Fos, as a key transcription factor in this signaling pathway, offers new insights for GBM treatment.
Research Highlights
- Key Finding: ROR1 activates the ERK/c-Fos signaling pathway by stabilizing GRB2, promoting GSC proliferation and self-renewal.
- Problem Solved: The study elucidates the specific mechanism of ROR1 in GBM, providing a new target for GBM treatment.
- Methodological Innovation: The study combines bioinformatic analysis, RNA-seq, immunoblotting, and immunofluorescence to comprehensively dissect the regulatory mechanism of ROR1.
- Specific Focus: The study focuses on the regulatory mechanisms of GSCs, offering new insights into GBM recurrence and treatment resistance.
Other Valuable Information
The study also found that ROR1 expression is significantly associated with poor prognosis in GBM patients, further validating its potential as a therapeutic target for GBM. Additionally, the study established a prognostic model based on stem cell markers through multivariate Cox regression analysis, providing a new tool for predicting the prognosis of GBM patients.
Through this study, we have gained a deeper understanding of the specific mechanisms of ROR1 in GBM and provided new targets and strategies for GBM treatment. Future research can further explore the application of ROR1-targeted therapy in GBM and validate its efficacy in clinical trials.