Project description:Genome wide DNA methylation profiling of control and mTORC2-suppressed glioblastoma cells (U87-EGFRvIII cells). The Illumina Infinium HumanMethylation EPIC BeadChip Array was used to obtain DNA methylation profiles with 865,918 probes in glioblastoma cell line samples. Samples included 2 control U87-MG cells without mTORC2 suppresion, and mTORC2-knockdown U87-MG cells with lentivirus-mediated suppression of mTORC2.
Project description:We herein demonstrate that mammalian target of rapamycin complex 2 (mTORC2), a critical core component of the growth factor signaling system, globally alters histone modification as well as transcriptome through metabolic reprogramming in the highly malignant brain tumor glioblastoma (GBM). Integrated analyses unravel that mTORC2 regulates mineral metabolism including iron trafficking via histone H3K9 acetylation of the ferritin promoter, facilitating GBM growth and survival.
Project description:We herein demonstrate that mammalian target of rapamycin complex 2 (mTORC2), a critical core component of the growth factor signaling system, globally alters histone acetylation through metabolic reprogramming in the highly malignant brain tumor glioblastoma (GBM). Integrated analyses unravel that mTORC2 regulates iron trafficking via histone H3K9 acetylation of the ferritin promoter, facilitating GBM growth and survival. These findings nominate mTORC2 as a critical epigenetic regulator of iron metabolism in cancer.
Project description:The mTOR complex 2 (mTORC2) has been implicated as a key regulator of glioblastoma cell migration. However, the roles of mTORC2 in the migrational control process have not been entirely elucidated. Here we elaborate that mTORC2 is crucial for GBM cell motility. Inhibition of mTORC2 resulted in impaired cell movement, affecting microfilaments and microtubules' functions. Later, we quantitatively characterized the mTORC2 interactome using affinity-purification mass spectrometry (AP-MS) in glioblastoma. We demonstrated that changes in cell migration ability alter mTORC2-associated proteins. These interacting proteins help determine the capability of glioma cell movement.
Project description:Glioblastoma (GBM) is a devastating primary brain cancer with a poor prognosis. GBM is associated with an abnormal mechanistic target of rapamycin (mTOR) signaling pathway, consisting of two distinct kinase complexes: mTORC1 and mTORC2. The complexes play critical roles in cell proliferation, survival, migration, metabolism, and DNA damage response. This study investigated the aberrant mTORC2 signaling pathway in GBM cells by performing quantitative phosphoproteomic analysis of U87MG cells under different drug treatment conditions. Interestingly, a functional analysis of phosphoproteome revealed that mTORC2 inhibition might be involved in double-strand break (DSB) repair. We further characterized the relationship between mTORC2 and BRISC and BRCA1-A Complex Member 1 (BABAM1). We demonstrated that pBABAM1 at Ser29 is regulated by mTORC2 to initiate DNA damage response, contributing to DNA repair and cancer cell survival. Accordingly, the inactivation of mTORC2 significantly ablated pBABAM1 (Ser29), reduced DNA repair activities in the nucleus, and promoted apoptosis of the cancer cells. Furthermore, we also recognized that histone H2AX phosphorylation at Ser139 (γH2AX) could be controlled by mTORC2 to repair the DNA. These results provided a better understanding of mTORC2 function in oncogenic DNA damage response and might lead to specific mTORC2 treatments for brain cancer patients in the future.
Project description:Primary glioblastoma, representing over 90% of adult glioblastoma, develop rapidly without preexisting lower-grade glioma. We have generated a mouse model of primary glioblastoma driven by a single p53 mutation. These p53-mutant gliomas lose the syntenic region of human chromosome 10q, which is mapped to mouse chr19 and chr7. Loss of mouse chr19, containing Pten, activates PI3K/Akt signaling. Rictor/mTORC2 deletion inhibits Akt signaling, causing a significant delay in p53-mutant driven glioma formation. Unexpectedly, Rictor/mTORC2 loss promotes p53-mutant driven medulloblastomas with unique features of pediatric SHH medulloblastoma. Mechanistically, Rictor/mTORC2 loss inhibits the generation of glioma precursor cells from neural stem/progenitor cells in the adult brain, while causing a delay in differentiation of granule cell precursors in the developing brain, a cell-of-origin of SHH medulloblastoma.
Project description:Glioblastoma (GBM) stem cells (GSCs) are largely associated with a poor prognosis of GBM. Although the importance of identifying and validating molecular markers in GBM has been emphasized, single markers covering all GSCs are lacking. Through in vitro antibody screening, in this study, we demonstrated that CD97 identifies GSCs as a novel surface marker. Compared to conventional well-known GSC markers, such as CD133, CD44 and CD15, only CD97 was notably detected in all tested patient-derived GSCs. GBM patients expressing high levels of CD97 experienced worse clinical outcomes, and were predictive of poor overall survival in the public database. CD97 is required for GSC proliferation and self-renewal and was shown to reduce mouse survival with aggressive tumor progression in an orthotopic xenograft model. A comparative transcriptomic analysis revealed that CD97 triggers mTORC2 signaling through Akt (S473) phosphorylation, enhancing the expression of downstream genes, including ARHGAP1, BZW1, and BZW2. Moreover, inhibition of mTORC2 signaling with the pharmacological inhibitor JR-AP2-011 suppressed GSC proliferation, self-renewal, and downstream gene expression. Furthermore, sorting of CD97-enriched cells from patient-derived GSCs revealed that CD97 promotes GSC self-renewal and tumorigenicity via mTORC2/AKT signaling. Thus, our findings suggest that CD97 may be a general GSC enrichment marker in GBM and that the CD97-related pathway might serve as a therapeutic target for GBM.
Project description:To screen miRNAs specifically regulated by mTORC1 or mTORC2, a global miRNA expression profile in MCF-7 cells treated with rapamycin or PP242 (mTORC1/2 kinase inhibitor) was developed using microarray. control, rapamycin or PP242 treated human MCF-7 cells were harvested 48h post-treatment and subjected to total RNA extraction.