Development of glioblastoma organoids and their applications in personalized therapy

Glioblastomas(GBMs)are the brain tumors with the highest malignancy and poorest prognoses.GBM is characterized by high heterogeneity and resistance to drug treatment.Organoids are 3-dimensional cultures that are constructed in vitro and comprise cell types highly similar to those in organs or tissues in vivo,thus simulating specific structures and physiological functions of organs.Organoids have been technically developed into an advanced ex vivo disease model used in basic and preclinical research on tumors.Brain organoids,which simulate the brain microenvironment while preserving tumor heterogeneity,have been used to predict patients’therapeutic responses to antitumor drugs,thus enabling a breakthrough in glioma research.GBM organoids provide an effective supplementary model that reflects human tumors’biological characteristics and functions in vitro more directly and accurately than traditional experimental models.Therefore,GBM organoids are widely applicable in disease mechanism research,drug development and screening,and glioma precision treatments.This review focuses on the development of various GBM organoid models and their applications in identifying new individualized therapies against drug-resistant GBM.

Temporal and spatial stability of the EM/PM molecular subtypes in adult diffuse glioma

Detailed characterizations of genomic alterations have not identified subtype-specific vulnerabilities in adult gliomas. Mapping gliomas into developmental programs may uncover new vulnerabilities that are not strictly related to genomic alterations. After identifying conserved gene modules co-expressed with EGFR or PDGFRA (EM or PM), we recently proposed an EM/PM classification scheme for adult gliomas in a histological subtype- and grade-independent manner. By using cohorts of bulk samples, paired primary and recurrent samples, multi-region samples from the same glioma, single-cell RNA-seq samples, and clinical samples, we here demonstrate the temporal and spatial stability of the EM and PM subtypes. The EM and PM subtypes, which progress in a subtype-specific mode, are robustly maintained in paired longitudinal samples. Elevated activities of cell proliferation, genomic instability and microenvironment, rather than subtype switching, mark recurrent gliomas. Within individual gliomas, the EM/PM subtype was preserved across regions and single cells. Malignant cells in the EM and PM gliomas were correlated to neural stem cell and oligodendrocyte progenitor cell compartment, respectively. Thus, while genetic makeup may change during progression and/or within different tumor areas, adult gliomas evolve within a neurodevelopmental framework of the EM and PM molecular subtypes. The dysregulated developmental pathways embedded in these molecular subtypes may contain subtype-specific vulnerabilities.

Blockage of EGFR/AKT and mevalonate pathways synergize the antitumor effect of temozolomide by reprogramming energy metabolism in glioblastoma

Background Metabolism reprogramming plays a vital role in glioblastoma(GBM)progression and recurrence by producing enough energy for highly proliferating tumor cells.In addition,metabolic reprogramming is crucial for tumor growth and immune-escape mechanisms.Epidermal growth factor receptor(EGFR)amplification and EGFR-vIII mutation are often detected in GBM cells,contributing to the malignant behavior.This study aimed to investigate the functional role of the EGFR pathway on fatty acid metabolism remodeling and energy generation.Methods Clinical GBM specimens were selected for single-cell RNA sequencing and untargeted metabolomics analysis.A metabolism-associated RTK-fatty acid-gene signature was constructed and verified.MK-2206 and MK-803 were utilized to block the RTK pathway and mevalonate pathway induced abnormal metabolism.Energy metabolism in GBM with activated EGFR pathway was monitored.The antitumor effect of Osimertinib and Atorvastatin assisted by temozolomide(TMZ)was analyzed by an intracranial tumor model in vivo.Results GBM with high EGFR expression had characteristics of lipid remodeling and maintaining high cholesterol levels,supported by the single-cell RNA sequencing and metabolomics of clinical GBM samples.Inhibition of the EGFR/AKT and mevalonate pathways could remodel energy metabolism by repressing the tricarboxylic acid cycle and modulating ATP production.Mechanistically,the EGFR/AKT pathway upregulated the expressions of acyl-CoA synthetase short-chain family member 3(ACSS3),acyl-CoA synthetase long-chain family member 3(ACSL3),and long-chain fatty acid elongation-related gene ELOVL fatty acid elongase 2(ELOVL2)in an NF-κB-dependent manner.Moreover,inhibition of the mevalonate pathway reduced the EGFR level on the cell membranes,thereby affecting the signal transduction of the EGFR/AKT pathway.Therefore,targeting the EGFR/AKT and mevalonate pathways enhanced the antitumor effect of TMZ in GBM cells and animal models.Conclusions Our findings not only uncovered the mechanism of metabolic reprogramming in EGFR-activated GBM but also provided a combinatorial therapeutic strategy for clinical GBM management.