Unlocking the Potential of the GSC-Associated lncRNA GIHCG as a Therapeutic Target in Glioblastoma - PROJECT SUMMARY Glioblastoma (GBM), the most aggressive and prevalent brain tumor, is marked by a grim prognosis despite standard treatments like surgery, chemotherapy, and radiotherapy. The limited success of these treatments is largely due to GBM's high recurrence and resistance, underscoring the urgent need for innovative treatment strategies. Numerous studies have indicated that glioblastoma stem cells (GSCs) are key drivers of tumor growth, therapy resistance, and relapse. Recent advancements in sequencing technologies revealed a vast landscape of long noncoding RNAs (lncRNAs), a class of RNAs with significant regulatory potential in cancer biology, that may serve as promising therapeutic targets. Here, we propose to characterize a newly identified GSC-associated lncRNA GIHCG, which is essential for GSC survival. Our preliminary data revealed that GIHCG- specific siRNA-mediated knockdown reduced GSC proliferation, migration, and self-renewal capacity. Notably, high levels of GIHCG expression correlate with poor patient outcomes in GBM, suggesting its oncogenic potential. Based on these findings, we hypothesize that GSC-associated oncogenic lncRNA GIHCG plays a critical role in GBM initiation and progression and could function as a potential biomarker and/or therapeutic target in GBM. To achieve this, we propose three specific aims: First, we will generate a GIHCG knockout in GSCs using a dual-guide CRISPR/Cas9 approach to delineate the molecular pathways involved in GSC proliferation, migration, and stemness (Aim 1). Second, we will assess the crucial role of GIHCG in GBM progression using preclinical ex vivo cerebral organoid and in vivo xenograft mouse models (Aim 2). Finally, we will investigate the functional interactions of GIHCG with chromatin and proteins using chromatin isolation by RNA purification (ChIRP) and ChIRP- mass spectrometry (ChIRP-MS) (Aim 3). In summary, this study aims to provide a comprehensive molecular characterization of the GSC-specific lncRNA GIHCG and elucidate its role in GBM progression, with the goal of advancing RNA-based therapy for high-grade brain cancers.
