Glioblastoma (GBM) exhibits profound metabolic plasticity for survival and therapeutic resistance, while the underlying mechanisms remain unclear. Here, we show that GBM stem cells reprogram the epigenetic landscape by producing substantial amounts of phosphocreatine (PCr). This production is attributed to the elevated transcription of brain-type creatine kinase, mediated by Zinc finger E-box binding homeobox 1. PCr inhibits the poly-ubiquitination of the chromatin regulator bromodomain containing protein 2 (BRD2) by outcompeting the E3 ubiquitin ligase SPOP for BRD2 binding. Pharmacological disruption of PCr biosynthesis by cyclocreatine (cCr) leads to BRD2 degradation and a decrease in its targets’ transcription, which inhibits chromosome segregation and cell proliferation. Notably, cyclocreatine treatment significantly impedes tumor growth and sensitizes tumors to a BRD2 inhibitor in mouse GBM models without detectable side effects. These findings highlight that high production of PCr is a druggable metabolic feature of GBM and a promising therapeutic target for GBM treatment. Significance: Glioblastoma (GBM) exhibits an adaptable metabolism crucial for survival and therapy resistance. We demonstrate that GBM stem cells modify their epigenetics by producing phosphocreatine (PCr), which prevents bromodomain containing protein 2 (BRD2) degradation and promotes accurate chromosome segregation. Disrupting PCr biosynthesis impedes tumor growth and improves the efficacy of BRD2 inhibitors in mouse GBM models.

Background: Glioma stem-like cells (GSCs) are key drivers of treatment resistance and recurrence in glioblastoma (GBM). Phosphoglycerate dehydrogenase (PHGDH), a crucial enzyme in the de novo serine synthesis pathway (SSP), is implicated in tumorigenesis and therapy resistance across various cancers. However, its specific role in GBM, particularly in radioresistance, remains poorly understood. Methods: In silico analysis of GBM patient data assessed SSP enrichment and PHGDH expression linked with tumor stemness. Comparative gene expression analysis focused on PHGDH in paired GBM specimens and GSCs. Genetic and pharmacological loss-of-function assays were performed in vitro and in vivo to evaluate PHGDH’s impact on GSC self-renewal and malignant progression. Comprehensive transcriptomic and metabolomic analyses, along with chromatin immunoprecipitation, mass spectrometry, and various other biochemical assays, were used to elucidate PHGDH-mediated mechanisms in GBM progression and radioresistance. Results: PHGDH expression is significantly elevated in GSCs, associated with aggressive glioma progression and poor clinical outcomes. PHGDH activation enhances GSC self-renewal by regulating redox homeostasis, facilitating one-carbon metabolism, and promoting DNA damage response via SSP activation. Importantly, MYC was identified as a crucial transcriptional regulator of PHGDH expression. Furthermore, genetic ablation or pharmacological inhibition of PHGDH markedly reduced tumor growth and increased tumor sensitivity to radiotherapy, thereby improving survival outcomes in orthotopic GSC-derived and patient-derived GBM xenograft models. Conclusions: This study underscores the pivotal role of MYC-mediated PHGDH activation in driving GSC malignant progression and radioresistance in GBM. Targeting PHGDH presents a promising approach to enhance radiotherapy efficacy in GBM patients.

Cisplatin‐based chemotherapy is the standard treatment for metastatic ovarian cancer (OC). However, chemoresistance continues to pose significant clinical challenges. Recent research has highlighted the baculoviral inhibitor of the apoptosis protein repeat‐containing 5 (BIRC5) as a member of the inhibitor of the apoptosis protein (IAP) family. Notably, BIRC5, which has robust anti‐apoptotic capabilities, is overexpressed in numerous cancers. Its dysfunction has been linked to challenges in cancer treatment. Yet, the role of BIRC5 in the chemoresistance of OC remains elusive. In our present study, we observed an upregulation of BIRC5 in cisplatin‐resistant cell lines. This upregulation was associated with enhanced chemoresistance, which was diminished when the expression of BIRC5 was silenced. Intriguingly, BIRC5 exhibited a high number of N6‐methyladenosine (m⁶A) binding sites. The modification of m⁶A was found to enhance the expression of BIRC5 by recognizing and binding to the 3′‐UTR of mRNA. Additionally, the insulin‐like growth factor 2 mRNA‐binding protein 1 (IGF2BP1) was shown to stabilize BIRC5 mRNA, synergizing with METTL3 and intensifying chemoresistance. Supporting these in vitro findings, our in vivo experiments revealed that tumors were significantly smaller in size and volume when BIRC5 was silenced. This reduction was notably counteracted by co‐silencing BIRC5 and overexpressing IGF2BP1. Our results underscored the pivotal role of BIRC5 in chemoresistance. The regulation of its expression and the stability of its mRNA were influenced by m⁶A modifications involving both METTL3 and IGF2BP1. These insights presented BIRC5 as a promising potential therapeutic target for addressing cisplatin resistance in OC.

Background: N6-methyladenosine (m6A) and 5-methylcytosine (m5C) are the main RNA methylation modifications involved in the oncogenesis of cancer. However, it remains obscure whether m6A/m5C-related long non-coding RNAs (lncRNAs) affect the development and progression of low grade gliomas (LGG). Methods: We summarized 926 LGG tumor samples with RNA-seq data and clinical information from The Cancer Genome Atlas and Chinese Glioma Genome Atlas. 105 normal brain samples with RNA-seq data from the Genotype Tissue Expression project were collected for control. We obtained a molecular classification cluster from the expression pattern of sreened lncRNAs. The least absolute shrinkage and selection operator Cox regression was employed to construct a m6A/m5C-related lncRNAs prognostic signature of LGG. In vitro experiments were employed to validate the biological functions of lncRNAs in our risk model. Results: The expression pattern of 14 sreened highly correlated lncRNAs could cluster samples into two groups, in which various clinicopathological features and the tumor immune microenvironment were significantly distinct. The survival time of cluster 1 was significantly reduced compared with cluster 2. This prognostic signature is based on 8 m6A/m5C-related lncRNAs (GDNF-AS1, HOXA-AS3, LINC00346, LINC00664, LINC00665, MIR155HG, NEAT1, RHPN1-AS1). Patients in the high-risk group harbored shorter survival times. Immunity microenvironment analysis showed B cells, CD4 + T cells, macrophages, and myeloid-derived DC cells were significantly increased in the high-risk group. Patients in high-risk group had the worse overall survival time regardless of followed TMZ therapy or radiotherapy. All observed results from the TCGA-LGG cohort could be validated in CGGA cohort. Afterwards, LINC00664 was found to promote cell viability, invasion and migration ability of glioma cells in vitro. Conclusion: Our study elucidated a prognostic prediction model of LGG by 8 m6A/m5C methylated lncRNAs and a critical lncRNA regulation function involved in LGG progression. High-risk patients have shorter survival times and a pro-tumor immune microenvironment.

Supplementary Table S4 shows PCr and BRD2 IHC staining scores in the serial sections of human glioma microarrays.

Supplementary Figures S1 shows that GSCs produce high levels of phosphocreatine through upregulating CKB. Supplementary Figures S2 shows that ZEB1 promotes CKB transcription in GSCs. Supplementary Figures S3 shows that knockdown of CKB impedes GBM growth. Supplementary Figures S4 shows that disruption of phosphocreatine production impedes GBM growth. Supplementary Figures S5 shows that cCr treatment shows no side effect on mice. Supplementary Figures S6 shows that phosphocreatine binds to BRD2 and inhibits its ubiquitin mediated proteasomal degradation. Supplementary Figures S7 shows that phosphocreatine promotes chromosome segregation and GSC proliferation through BRD2 mediated transcription. Supplementary Figures S8 shows that disruption of phosphocreatine biosynthesis by cCr improves JQ1 therapeutic efficacy in GBM.