LncRNA-Mediated TPI1 and PKM2 Promote Self-Renewal and Chemoresistance in GBM.

Temozolomide (TMZ) resistance is one of the major reasons for poor prognosis in patients with glioblastoma (GBM). Long noncoding RNAs (lncRNAs) are involved in multiple biological processes, including TMZ resistance. Linc00942 is a potential regulator of TMZ sensitivity in GBM cells is shown previously. However, the underlying mechanism of TMZ resistance induced by Linc00942 is unknown. In this study, the sequence of Linc00942 by rapid amplification of cDNA ends assay in TMZ-resistant GBM cells is identified and confirmed that Linc00942 contributes to self-renewal and TMZ resistance in GBM cells. Chromatin isolation by RNA purification followed by mass spectrometry (ChIRP-MS) and followed by Western blotting (ChIRP-WB) assays shows that Linc00492 interacted with TPI1 and PKM2, subsequently promoting their phosphorylation, dimerization, and nuclear translocation. The interaction of Linc00942 with TPI1 and PKM2 leads to increased acetylation of H3K4 and activation of the STAT3/P300 axis, resulting in the marked transcriptional activation of SOX9. Moreover, the knockdown of SOX9 reversed TMZ resistance induced by Linc00492 both in vitro and in vivo. In summary, Linc00942 strongly promotes SOX9 expression by interacting with TPI1 and PKM2 is found, thereby driving self-renewal and TMZ resistance in GBM cells. These findings suggest potential combined therapeutic strategies to overcome TMZ resistance in patients with GBM.

Polymer-locking fusogenic liposomes for glioblastoma-targeted siRNA delivery and CRISPR-Cas gene editing.

In patients with glioblastoma (GBM), upregulated midkine (MDK) limits the survival benefits conferred by temozolomide (TMZ). RNA interference (RNAi) and CRISPR-Cas9 gene editing technology are attractive approaches for regulating MDK expression. However, delivering these biologics to GBM tissue is challenging. Here we demonstrate a polymer-locking fusogenic liposome (Plofsome) that can be transported across the blood-brain barrier (BBB) and deliver short interfering RNA or CRISPR-Cas9 ribonucleoprotein complexes into the cytoplasm of GBM cells. Plofsome is designed by integrating a 'lock' into the fusogenic liposome using a traceless reactive oxygen species (ROS)-cleavable linker so that fusion occurs only after crossing the BBB and entering the GBM tissue with high ROS levels. Our results showed that MDK suppression by Plofsomes significantly reduced TMZ resistance and inhibited GBM growth in orthotopic brain tumour models. Importantly, Plofsomes are effective only at tumour sites and not in normal tissues, which improves the safety of combined RNAi and CRISPR-Cas9 therapeutics.

Histone lactylation-derived LINC01127 promotes the self-renewal of glioblastoma stem cells via the cis-regulating the MAP4K4 to activate JNK pathway.

Gliomas are the most prevalent and aggressive brain tumors, exhibiting high proliferation, abnormal glycolysis, and poor prognosis. LncRNAs act as regulatory molecules and play crucial roles in the malignant behaviors of GBM cells, including cell self-renewal. However, the regulatory mechanisms involved are largely unknown. In this study, we performed bioinformatics analysis to explore NF-κB pathway-related lncRNAs. ECAR and qRT-PCR were used to measure the relationship between glycolytic activity and lncRNA expression. Assays such as RIP-PCR and ChIP-PCR were employed to reveal the regulatory mechanisms of the lncRNA. Neurosphere formation and limiting dilution assays were performed to evaluate the self-renewal capacity of GBM cells. In our study, we identified an NF-κB pathway-related lncRNA named LINC01127 in GBM, which was found to be associated with poor progression of GBM. Functionally, the NF-κB pathway promoted warburg effect, which, in turn, induced the lactylation of H3 histone and increased the expression of LINC01127. Consequently, this enhancement of LINC01127 expression led to the promotion of self-renewal in GBM cells. Furthermore, LINC01127 regulated MAP4K4 expression in cis by directly guiding POLR2A to the MAP4K4 promoter regions, thereby leading to JNK pathway activation, and ultimately modulating the self-renewal of GBM cells. Moreover, the activated JNK pathway promoted the phosphorylation of IκBα. Overall, targeting LINC01127-mediated axis impeded orthotopic tumor growth in GBM xenografts. Taken together these results revealed that warburg effect-induced histone lactylation drives NF-κB-related LINC01127 expression, thereby promoting the self-renewal of GBM cells through the MAP4K4/JNK/NF-κB axis, and providing substantial evidence that LINC01127 might provide a novel therapeutic strategy for GBM patients.

Using integrated analysis from multicentre studies to identify RNA methylation-related lncRNA risk stratification systems for glioma.

BACKGROUND: N6-methyladenosine (m6A), 5-methylcytosine (m5C) and N1-methyladenosine (m1A) are the main RNA methylation modifications involved in the progression of cancer. However, it is still unclear whether RNA methylation-related long noncoding RNAs (lncRNAs) affect the prognosis of glioma. METHODS: We summarized 32 m6A/m5C/m1A-related genes and downloaded RNA-seq data and clinical information from The Cancer Genome Atlas (TCGA) database. Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were used to identify differentially expressed (DE-) RNA methylation-related lncRNAs in order to construct a prognostic signature of glioma and in order to determine their correlation with immune function, immune therapy and drug sensitivity. In vitro and in vivo assays were performed to elucidate the effects of RNA methylation-related lncRNAs on glioma. RESULTS: A total of ten RNA methylation-related lncRNAs were used to construct a survival and prognosis signature, which had good independent prediction ability for patients. It was found that the high-risk group had worse overall survival (OS) than the low-risk group in all cohorts. In addition, the risk group informed the immune function, immunotherapy response and drug sensitivity of patients with glioma in different subgroups. Knockdown of RP11-98I9.4 and RP11-752G15.8 induced a more invasive phenotype, accelerated cell growth and apparent resistance to temozolomide (TMZ) both in vitro and in vivo. We observed significantly elevated global RNA m5C and m6A levels in glioma cells. CONCLUSION: Our study determined the prognostic implication of RNA methylation-related lncRNAs in gliomas, established an RNA methylation-related lncRNA prognostic model, and elucidated that RP11-98I9.4 and RP11-752G15.8 could suppress glioma proliferation, migration and TMZ resistance. In the future, these RNA methylation-related lncRNAs may become a new choice for immunotherapy of glioma.

Glioblastoma Cell-Derived lncRNA-Containing Exosomes Induce Microglia to Produce Complement C5, Promoting Chemotherapy Resistance.

Glioblastoma (GBM), the most common malignant primary brain cancer in adults, nearly always becomes resistant to current treatments, including the chemotherapeutic temozolomide (TMZ). The long noncoding RNA (lncRNA) TMZ-associated lncRNA in GBM recurrence (lnc-TALC) promotes GBM resistance to TMZ. Exosomes can release biochemical cargo into the tumor microenvironment (TME) or transfer their contents, including lncRNAs, to other cells as a form of intercellular communication. In this study, we found that lnc-TALC could be incorporated into exosomes and transmitted to tumor-associated macrophages (TAM) and could promote M2 polarization of the microglia. This M2 polarization correlated with secretion of the complement components C5/C5a, which occurred downstream of lnc-TALC binding to ENO1 to promote the phosphorylation of p38 MAPK. In addition, C5 promoted the repair of TMZ-induced DNA damage, leading to chemotherapy resistance, and C5a-targeted immunotherapy showed improved efficacy that limited lnc-TALC-mediated TMZ resistance. Our results reveal that exosome-transmitted lnc-TALC could remodel the GBM microenvironment and reduce tumor sensitivity to TMZ chemotherapy, indicating that the lnc-TALC-mediated cross-talk between GBM cells and microglia could attenuate chemotherapy efficacy and pointing to potential combination therapy strategies to overcome TMZ resistance in GBM.See related Spotlight by Zhao and Xie, p. 1372.