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ARG1-expressing microglia show a distinct molecular signature and modulate postnatal development and function of the mouse brain. Nat Neurosci 2023:10.1038/s41593-023-01326-3. [PMID: 37169859 DOI: 10.1038/s41593-023-01326-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 04/11/2023] [Indexed: 05/13/2023]
Abstract
Molecular diversity of microglia, the resident immune cells in the CNS, is reported. Whether microglial subsets characterized by the expression of specific proteins constitute subtypes with distinct functions has not been fully elucidated. Here we describe a microglial subtype expressing the enzyme arginase-1 (ARG1; that is, ARG1+ microglia) that is found predominantly in the basal forebrain and ventral striatum during early postnatal mouse development. ARG1+ microglia are enriched in phagocytic inclusions and exhibit a distinct molecular signature, including upregulation of genes such as Apoe, Clec7a, Igf1, Lgals3 and Mgl2, compared to ARG1- microglia. Microglial-specific knockdown of Arg1 results in deficient cholinergic innervation and impaired dendritic spine maturation in the hippocampus where cholinergic neurons project, which in turn results in impaired long-term potentiation and cognitive behavioral deficiencies in female mice. Our results expand on microglia diversity and provide insights into microglia subtype-specific functions.
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Abstract
Macroautophagy/autophagy is a tightly regulated catabolic process, which contributes at baseline level to cellular homeostasis, and upon its stimulation to the adaptive cellular response to intra- and extracellular stress stimuli. Decrease of autophagy activity is occurring upon aging and thought to contribute to age-related-diseases. Recently, we uncovered, upon autophagy induction, the role of de novo DNMT3A (DNA methyltransferase 3 alpha)-mediated DNA methylation on expression of the MAP1LC3 (microtubule associated protein 1 light chain 3) proteins, core components of the autophagy pathway, which resulted in reduced baseline autophagy activity. Here, we report that serine/threonine kinase ULK3 (unc-51 like kinase 3)-dependent activation of GLI1 (GLI family zinc finger 1) contributes to the transcriptional upregulation of DNMT3A gene expression upon autophagy induction, thereby bringing additional understanding of the long-term effect of autophagy induction and a possible mechanism for its decline upon aging, pathological conditions, or in response to treatment interventions.Abbreviations: CBZ: carbamazepine; ChIP: chromatin immunoprecipitation; Clon: clonidine; DNMT3A: DNA methyltransferase 3 alpha; GLI1: GLI family zinc finger 1; GLI2: GLI family zinc finger 2; MAP1LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; PLA: proximity ligation assay; RT-qPCR: quantitative reverse transcription PCR; shRNA: small hairpin RNA; siRNA: small interfering RNA; Treh: trehalose; ULK3: unc-51 like kinase 3.
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Atg7 deficiency in microglia drives an altered transcriptomic profile associated with an impaired neuroinflammatory response. Mol Brain 2021; 14:87. [PMID: 34082793 PMCID: PMC8173846 DOI: 10.1186/s13041-021-00794-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/18/2021] [Indexed: 02/08/2023] Open
Abstract
Microglia, resident immunocompetent cells of the central nervous system, can display a range of reaction states and thereby exhibit distinct biological functions across development, adulthood and under disease conditions. Distinct gene expression profiles are reported to define each of these microglial reaction states. Hence, the identification of modulators of selective microglial transcriptomic signature, which have the potential to regulate unique microglial function has gained interest. Here, we report the identification of ATG7 (Autophagy-related 7) as a selective modulator of an NF-κB-dependent transcriptional program controlling the pro-inflammatory response of microglia. We also uncover that microglial Atg7-deficiency was associated with reduced microglia-mediated neurotoxicity, and thus a loss of biological function associated with the pro-inflammatory microglial reactive state. Further, we show that Atg7-deficiency in microglia did not impact on their ability to respond to alternative stimulus, such as one driving them towards an anti-inflammatory/tumor supportive phenotype. The identification of distinct regulators, such as Atg7, controlling specific microglial transcriptional programs could lead to developing novel therapeutic strategies aiming to manipulate selected microglial phenotypes, instead of the whole microglial population with is associated with several pitfalls.
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The DNA methyltransferase DNMT3A contributes to autophagy long-term memory. Autophagy 2021; 17:1259-1277. [PMID: 32876528 PMCID: PMC8143216 DOI: 10.1080/15548627.2020.1816664] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 10/25/2022] Open
Abstract
Macroautophagy/autophagy is a conserved catabolic pathway that targets cytoplasmic components for their degradation and recycling in an autophagosome-dependent lysosomal manner. Under physiological conditions, this process maintains cellular homeostasis. However, autophagy can be stimulated upon different forms of cellular stress, ranging from nutrient starvation to exposure to drugs. Thus, this pathway can be seen as a central component of the integrated and adaptive stress response. Here, we report that even brief induction of autophagy is coupled in vitro to a persistent downregulation of the expression of MAP1LC3 isoforms, which are key components of the autophagy core machinery. In fact, DNA-methylation mediated by de novo DNA methyltransferase DNMT3A of MAP1LC3 loci upon autophagy stimulation leads to the observed long-term decrease of MAP1LC3 isoforms at transcriptional level. Finally, we report that the downregulation of MAP1LC3 expression can be observed in vivo in zebrafish larvae and mice exposed to a transient autophagy stimulus. This epigenetic memory of autophagy provides some understanding of the long-term effect of autophagy induction and offers a possible mechanism for its decline upon aging, pathological conditions, or in response to treatment interventions.Abbreviations: ACTB: actin beta; ATG: autophagy-related; 5-Aza: 5-aza-2'-deoxycytidine; BafA1: bafilomycin A1; CBZ: carbamazepine; CDKN2A: cyclin dependent kinase inhibitor 2A; ChIP: chromatin immunoprecipitation; Clon.: clonidine; CpG: cytosine-guanine dinucleotide: DMSO: dimethyl sulfoxide; DNA: deoxyribonucleic acid; DNMT: DNA methyltransferase; DNMT1: DNA methyltransferase 1; DNMT3A: DNA methyltransferase alpha; DNMT3B: DNA methyltransferase beta; dpf: days post-fertilization; EBSS: Earle's balanced salt solution; EM: Zebrafish embryo medium; GABARAP: GABA type A receptor associated protein; GABARAPL1: GABA type A receptor associated protein like 1; GABARAPL2: GABA type A receptor associated protein like 2; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GRO-Seq: Global Run-On sequencing; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MAP1LC3A: microtubule-associated protein 1 light chain 3 alpha; MAP1LC3B: microtubule-associated protein 1 light chain 3 beta; MAP1LC3B2: microtubule-associated protein 1 light chain 3 beta 2; MEM: minimum essential medium; MEF: mouse embryonic fibroblasts; mRNA: messenger RNA; MTOR: mechanistic target of rapamycin kinase; PBS: phosphate-buffered saline; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; RB1CC1/FIP200: RB1 inducible coiled-coil 1; RT-qPCR: quantitative reverse transcription polymerase chain reaction; SQSTM1/p62: sequestosome 1; Starv.: starvation; Treh.: trehalose; ULK1: unc-51 like autophagy activating kinase 1.
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Multifaceted microglia - key players in primary brain tumour heterogeneity. Nat Rev Neurol 2021; 17:243-259. [PMID: 33692572 DOI: 10.1038/s41582-021-00463-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2021] [Indexed: 01/31/2023]
Abstract
Microglia are the resident innate immune cells of the immune-privileged CNS and, as such, represent the first line of defence against tissue injury and infection. Given their location, microglia are undoubtedly the first immune cells to encounter a developing primary brain tumour. Our knowledge of these cells is therefore important to consider in the context of such neoplasms. As the heterogeneous nature of the most aggressive primary brain tumours is thought to underlie their poor prognosis, this Review places a special emphasis on the heterogeneity of the tumour-associated microglia and macrophage populations present in primary brain tumours. Where available, specific information on microglial heterogeneity in various types and subtypes of brain tumour is included. Emerging evidence that highlights the importance of considering the heterogeneity of both the tumour and of microglial populations in providing improved treatment outcomes for patients is also discussed.
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Abstract
BACKGROUND Diffuse intrinsic pontine gliomas (DIPG), within diffuse midline gliomas are aggressive pediatric brain tumors characterized by histone H3-K27M mutation. Small-molecule inhibitors for the EZH2-H3K27 histone methyltransferase have shown promise in preclinical animal models of DIPG, despite having little effect on DIPG cells in vitro. Therefore, we hypothesized that the effect of EZH2 inhibition could be mediated through targeting of this histone modifying enzyme in tumor-associated microglia. METHODS Primary DIPG tissues, and cocultures between microglia and patient-derived DIPG or -pediatric high-grade glioma (pHGG) cell lines, were used to establish the H3-K27M status of each cell type. Antisense RNA strategies were used to target EZH2 gene expression in both microglia and glioma cells. Microglia anti-tumoral properties were assessed by gene expression profile, tumor cell invasion capacity, microglial phagocytic activity, and associated tumor cell death. RESULTS In primary DIPG tissues, microglia do not carry the H3-K27M mutation, otherwise characteristic of the cancer cells. Activation of a microglial tumor-supportive phenotype by pHGG, independently of their H3-K27M status, is associated with a transient H3K27me3 downregulation. Repression of EZH2 in DIPG cells has no impact on tumor cell survival or their ability to activate microglia. However, repression of EZH2 in microglia induces an anti-tumor phenotype resulting in decreased cancer cell invasion capability, increased microglial phagocytosis, and tumor-related cell death. CONCLUSIONS These results indicate that microglia, beyond the tumor cells, contribute to the observed response of DIPG to EZH2 inhibition. Results highlight the potential importance of microglia as a new therapeutic avenue in DIPG.
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Cytosine methylation of mature microRNAs inhibits their functions and is associated with poor prognosis in glioblastoma multiforme. Mol Cancer 2020; 19:36. [PMID: 32098627 PMCID: PMC7041276 DOI: 10.1186/s12943-020-01155-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 02/13/2020] [Indexed: 12/23/2022] Open
Abstract
Background Literature reports that mature microRNA (miRNA) can be methylated at adenosine, guanosine and cytosine. However, the molecular mechanisms involved in cytosine methylation of miRNAs have not yet been fully elucidated. Here we investigated the biological role and underlying mechanism of cytosine methylation in miRNAs in glioblastoma multiforme (GBM). Methods RNA immunoprecipitation with the anti-5methylcytosine (5mC) antibody followed by Array, ELISA, dot blot, incorporation of a radio-labelled methyl group in miRNA, and miRNA bisulfite sequencing were perfomred to detect the cytosine methylation in mature miRNA. Cross-Linking immunoprecipiation qPCR, transfection with methylation/unmethylated mimic miRNA, luciferase promoter reporter plasmid, Biotin-tagged 3’UTR/mRNA or miRNA experiments and in vivo assays were used to investigate the role of methylated miRNAs. Finally, the prognostic value of methylated miRNAs was analyzed in a cohorte of GBM pateints. Results Our study reveals that a significant fraction of miRNAs contains 5mC. Cellular experiments show that DNMT3A/AGO4 methylated miRNAs at cytosine residues inhibit the formation of miRNA/mRNA duplex and leading to the loss of their repressive function towards gene expression. In vivo experiments show that cytosine-methylation of miRNA abolishes the tumor suppressor function of miRNA-181a-5p miRNA for example. Our study also reveals that cytosine-methylation of miRNA-181a-5p results is associated a poor prognosis in GBM patients. Conclusion Together, our results indicate that the DNMT3A/AGO4-mediated cytosine methylation of miRNA negatively. Graphical abstract ![]()
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Epigenetic protein complexes: the adequate candidates for the use of a new generation of epidrugs in personalized and precision medicine in cancer. Epigenomics 2020; 12:171-177. [DOI: 10.2217/epi-2019-0169] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Until recently, drug development in oncology was focused on treating most patients for a specific cancer type without taking in account the heterogeneity between these patients in term of response to treatment. Therefore, this type of broad treatment approach excludes the treatment of patient not responding to disease-specific common drugs. In this review, we focus on the different types of epigenetic drugs currently used as DNA methylation inhibitor agents and their limits in patient care due to their lack of specificity. We also highlight the emergence of a new type of epidrug with higher target specificity due to their original mechanism of action: the disruption of protein complexes involved in the epigenetic modifications.
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The Rules of Engagement: Do Microglia Seal the Fate in the Inverse Relation of Glioma and Alzheimer's Disease? Front Cell Neurosci 2019; 13:522. [PMID: 31824268 PMCID: PMC6879422 DOI: 10.3389/fncel.2019.00522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 11/07/2019] [Indexed: 12/30/2022] Open
Abstract
Microglia, the immune cells of the brain, play a major role in the maintenance of brain homeostasis and constantly screen the brain environment to detect any infection or damage. Once activated by a stimulus, microglial cells initiate an immune response followed by the resolution of brain inflammation. A failure or deviation in the housekeeping function of these guardian cells can lead to multiple diseases, including brain cancer and neurodegenerative diseases such as Alzheimer's disease (AD). A small number of studies have investigated the causal relation of both diseases, thereby revealing an inverse relationship where cancer patients have a reduced risk to develop AD and vice versa. In this review, we aim to shed light on the role of microglia in the fate to develop specifically glioma as one type of cancer or AD. We will examine the common and/or opposing genetic predisposition as well as associated pathways of these diseases to unravel a possible involvement of microglia in the occurrence of either disease. Lastly, a set of guidelines will be proposed for future research and diagnostics to clarify and improve the knowledge on the role of microglia in the decision toward one pathology or another.
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TET2 Regulates the Neuroinflammatory Response in Microglia. Cell Rep 2019; 29:697-713.e8. [PMID: 31618637 DOI: 10.1016/j.celrep.2019.09.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 04/18/2019] [Accepted: 09/06/2019] [Indexed: 12/17/2022] Open
Abstract
Epigenomic mechanisms regulate distinct aspects of the inflammatory response in immune cells. Despite the central role for microglia in neuroinflammation and neurodegeneration, little is known about their epigenomic regulation of the inflammatory response. Here, we show that Ten-eleven translocation 2 (TET2) methylcytosine dioxygenase expression is increased in microglia upon stimulation with various inflammogens through a NF-κB-dependent pathway. We found that TET2 regulates early gene transcriptional changes, leading to early metabolic alterations, as well as a later inflammatory response independently of its enzymatic activity. We further show that TET2 regulates the proinflammatory response in microglia of mice intraperitoneally injected with LPS. We observed that microglia associated with amyloid β plaques expressed TET2 in brain tissue from individuals with Alzheimer's disease (AD) and in 5xFAD mice. Collectively, our findings show that TET2 plays an important role in the microglial inflammatory response and suggest TET2 as a potential target to combat neurodegenerative brain disorders.
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Abstract
Microglia, resident immune cells of the central nervous system, fulfill multiple functions in the brain throughout life. These microglial functions range from participation in innate and adaptive immune responses, involvement in the development of the brain and its homeostasis maintenance, to contribution to degenerative, traumatic, and proliferative diseases; and take place in the developing, the aging, the healthy, or the diseased brain. Thus, an impressive level of cellular plasticity, appears as a requirement for the pleiotropic biological functions of microglia. Epigenetic changes, including histone modifications or DNA methylation as well as microRNA expression, are important modifiers of gene expression, and have been involved in cell phenotype regulation and reprogramming and are therefore part of the mechanisms regulating cellular plasticity. Here, we review and discuss the epigenetic mechanisms, which are emerging as contributors to this microglial cellular plasticity and thereby can constitute interesting targets to modulate microglia associated brain diseases, including developmental diseases, neurodegenerative diseases as well as cancer.
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Glioma-induced SIRT1-dependent activation of hMOF histone H4 lysine 16 acetyltransferase in microglia promotes a tumor supporting phenotype. Oncoimmunology 2017; 7:e1382790. [PMID: 29308302 PMCID: PMC5749650 DOI: 10.1080/2162402x.2017.1382790] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 09/14/2017] [Accepted: 09/16/2017] [Indexed: 11/06/2022] Open
Abstract
High-grade gliomas are malignant aggressive primary brain tumors with limited therapeutic options, and dismal prognosis for patients. Microglia, the resident immune cells of the brain, are recruited and reprogrammed into tumor-supporting cells by glioma cells, which in turn positively influence tumor expansion and infiltration into surrounding brain tissues. Here, we report that glioma-induced microglia conversion is coupled to an increase of histone H4 lysine 16 (H4K16) acetylation level in microglia, through increased nuclear localization of the deacetylase SIRT1, which in turn results in deacetylation of the H4K16 acetyltransferase hMOF and its recruitment to the chromatin at promoter regions of microglial target genes. Furthermore, we demonstrate that manipulation of the microglial H4K16 acetylation level, taking advantage of the intrinsic H4K16 deacetylase or acetyltransferase activities of SIRT1 and hMOF, respectively, modulated the tumor-supporting function of microglia. This study provides evidence that post-translational modifications of histones and the histone-modifying enzymes controlling them, such as H4K16 acetylation regulated by hMOF and SIRT1, are part of the microglial pro-tumoral activation pathway initiated by glioma cancer cells and represent potentially novel therapeutic targets.
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KLRC3, a Natural Killer receptor gene, is a key factor involved in glioblastoma tumourigenesis and aggressiveness. J Cell Mol Med 2016; 21:244-253. [PMID: 27641066 PMCID: PMC5264145 DOI: 10.1111/jcmm.12960] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/26/2016] [Indexed: 01/06/2023] Open
Abstract
Glioblastoma is the most lethal brain tumour with a poor prognosis. Cancer stem cells (CSC) were proposed to be the most aggressive cells allowing brain tumour recurrence and aggressiveness. Current challenge is to determine CSC signature to characterize these cells and to develop new therapeutics. In a previous work, we achieved a screening of glycosylation-related genes to characterize specific genes involved in CSC maintenance. Three genes named CHI3L1, KLRC3 and PRUNE2 were found overexpressed in glioblastoma undifferentiated cells (related to CSC) compared to the differentiated ones. The comparison of their roles suggest that KLRC3 gene coding for NKG2E, a protein initially identified in NK cells, is more important than both two other genes in glioblastomas aggressiveness. Indeed, KLRC3 silencing decreased self-renewal capacity, invasion, proliferation, radioresistance and tumourigenicity of U87-MG glioblastoma cell line. For the first time we report that KLRC3 gene expression is linked to glioblastoma aggressiveness and could be a new potential therapeutic target to attenuate glioblastoma.
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Specific Inhibition of DNMT3A/ISGF3γ Interaction Increases the Temozolomide Efficiency to Reduce Tumor Growth. Am J Cancer Res 2016; 6:1988-1999. [PMID: 27698935 PMCID: PMC5039338 DOI: 10.7150/thno.9150] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 07/16/2015] [Indexed: 11/28/2022] Open
Abstract
DNA methylation is a fundamental feature of genomes and is a candidate for pharmacological manipulation that might have important therapeutic advantage. Thus, DNA methyltransferases (DNMTs) appear to be ideal targets for drug intervention. By focusing on interactions existing between DNMT3A and DNMT3A-binding protein (D3A-BP), our work identifies the DNMT3A/ISGF3γ interaction such as a biomarker whose the presence level is associated with a poor survival prognosis and with a poor prognosis of response to the conventional chemotherapeutic treatment of glioblastoma multiforme (radiation plus temozolomide). Our data also demonstrates that the disruption of DNMT3A/ISGF3γ interactions increases the efficiency of chemotherapeutic treatment on established tumors in mice. Thus, our data opens a promising and innovative alternative to the development of specific DNMT inhibitors.
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DNMT Inhibitors in Cancer, Current Treatments and Future Promising Approach: Inhibition of Specific DNMT-Including Complexes. ACTA ACUST UNITED AC 2015. [DOI: 10.2174/2214083201666150221002056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Specific inhibition of DNMT1/CFP1 reduces cancer phenotypes and enhances chemotherapy effectiveness. Epigenomics 2015; 6:267-75. [PMID: 25111481 DOI: 10.2217/epi.14.18] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
AIM DNA methylation is a fundamental biologic process of genomes and is a candidate for pharmacological manipulation that might have important therapeutic advantages. Thus, DNA methyltransferases (DNMTs) appear to be ideal targets for drug intervention. MATERIALS & METHODS To develop a new generation of DNMT inhibitor, we analyzed the ability of peptides to selectively inhibit certain DNMT1-incuding complexes. RESULTS Our study demonstrates that the disruption of DNMT1/CFP1-including complexes increases the efficiency of chemotherapeutic treatment on established tumors in mice. CONCLUSION Our data opens a promising and innovative alternative to the development of DNMT inhibitors.
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Histone H3 phosphorylation in GBM: a new rational to guide the use of kinase inhibitors in anti-GBM therapy. Am J Cancer Res 2015; 5:12-22. [PMID: 25553095 PMCID: PMC4265745 DOI: 10.7150/thno.8799] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 03/31/2014] [Indexed: 12/11/2022] Open
Abstract
Histones post-translational modifications (PTMs) are crucial components of diverse processes that modulate chromatin. Among the histones PTMs, the histones phosphorylation appears such crucial since it plays a significant role into DNA repair structure, transcription and chromatin compaction during cell division and apoptosis. However, little is known about the prognostic value of the histone phosphorylation in human cancer. This point could be considerate such as an important gap in anti-cancer therapy since the use of adequate kinase inhibitors could remedy to the aberrant histone phosphorylation associated with a poor prognosis factor. To remedy at this situation, we analyzed the phosphorylation level of histone H3 at the residues T3, T6, S10, S28, Y41 and T45 in a collection of 42 glioblastoma multiformes (GBM). Our data indicated that the high level of pH3T6, pH3S10 and pH3Y41 are signatures associated with a poor prognosis of overall survival (OS) of GBM treated with the "temozolomide and irradiation standard" treatment of GBM (named TMZ+Irad treatment). Our data also showed that these signatures are correlated with the high activity of kinases already described as writers of the pH3T6, pH3S10 and pH3Y41 i.e. the PKC, Aurora-B and JAK2, respectively. Finally, our analysis revealed that the use of Enzastaurin, AZD1152, and AZD1480 abrogated the high level of pH3T6, pH3S10 and pH3Y41 while increasing the sensitivity to the "temozolomide and irradiation"-induced cell death. To conclude, it appears that this work provides biomarkers for patient stratification for a therapy including kinase inhibitors.
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Control of glioma cell death and differentiation by PKM2-Oct4 interaction. Cell Death Dis 2014; 5:e1036. [PMID: 24481450 PMCID: PMC4040711 DOI: 10.1038/cddis.2013.561] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 12/11/2013] [Accepted: 12/13/2013] [Indexed: 12/12/2022]
Abstract
Glioma stem cells are highly resistant to cell death and as such are supposed to contribute to tumor recurrence by eluding anticancer treatments. Here, we show that spheroids that contain rat neural stem cells (NSCs) or rat glioma stem cells (cancer stem cells, CSCs) express isoforms 1 and 2 of pyruvate kinase (PKM1 and PKM2); however, the expression of PKM2 is considerably higher in glioma spheroids. Silencing of PKM2 enhances both apoptosis and differentiation of rat and human glioma spheroids. We establish that PKM2 was implicated in glioma spheroid differentiation through its interaction with Oct4, a major regulator of self-renewal and differentiation in stem cells. The small molecule Dichloroacetate (DCA), a pyruvate dehydrogenase kinase inhibitor, increases the amount of PKM2/Oct4 complexes and thus inhibited Oct4-dependent gene expression. Taken together, our results highlight a new molecular pathway through which PKM2 can manage gliomagenesis via the control of glioma stemness by Oct4.
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Specific inhibition of one DNMT1-including complex influences tumor initiation and progression. Clin Epigenetics 2013; 5:9. [PMID: 23809695 PMCID: PMC3727981 DOI: 10.1186/1868-7083-5-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 06/03/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Reactivation of silenced tumor suppressor genes by DNMT inhibitors has provided an alternative approach to cancer therapy. However, DNMT inhibitors have also been shown to induce or enhance tumorigenesis via DNA hypomethylation-induced oncogene activation and chromosomal instability. To develop more specific DNMT inhibitors for efficient cancer therapy, we compared the effects of peptides designed to specifically disrupt the interaction of DNMT1 with different proteins. FINDINGS Our data indicated that the use of an unspecific DNMT inhibitor (5aza-2deoxycytidine), a DNMT1 inhibitor (procainamide) or peptides disrupting the DNMT1/PCNA, DNMT1/EZH2, DNMT1/HDAC1, DNMT1/DNMT3b and DNMT1/HP1 interactions promoted or enhanced in vivo tumorigenesis in a mouse glioma model. In contrast, a peptide disrupting the DNMT1/DMAP1 interaction, which per se did not affect tumor growth, sensitized cancer cells to chemotherapy/irradiation-induced cell death. Finally, our data indicated that the peptide disrupting the DNMT1/DMAP1 interaction increased the efficiency of temozolomide treatment. CONCLUSION Our data suggest that the DNMT1/DMAP1 interaction could be an effective anti-cancer target and opens a new avenue for the development of new strategies to design DNMT inhibitors.
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Glycosylation-related gene expression is linked to differentiation status in glioblastomas undifferentiated cells. Cancer Lett 2011; 312:24-32. [DOI: 10.1016/j.canlet.2011.07.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 07/21/2011] [Accepted: 07/21/2011] [Indexed: 01/06/2023]
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Disruption of Dnmt1/PCNA/UHRF1 interactions promotes tumorigenesis from human and mice glial cells. PLoS One 2010; 5:e11333. [PMID: 20613874 PMCID: PMC2894052 DOI: 10.1371/journal.pone.0011333] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 06/05/2010] [Indexed: 01/12/2023] Open
Abstract
Global DNA hypomethylation is a hallmark of cancer cells, but its molecular mechanisms have not been elucidated. Here, we show that the disruption of Dnmt1/PCNA/UHRF1 interactions promotes a global DNA hypomethylation in human gliomas. We then demonstrate that the Dnmt1 phosphorylations by Akt and/or PKC abrogate the interactions of Dnmt1 with PCNA and UHRF1 in cellular and acelluar studies including mass spectrometric analyses and the use of primary cultured patient-derived glioma. By using methylated DNA immunoprecipitation, methylation and CGH arrays, we show that global DNA hypomethylation is associated with genes hypomethylation, hypomethylation of DNA repeat element and chromosomal instability. Our results reveal that the disruption of Dnmt1/PCNA/UHRF1 interactions acts as an oncogenic event and that one of its signatures (i.e. the low level of mMTase activity) is a molecular biomarker associated with a poor prognosis in GBM patients. We identify the genetic and epigenetic alterations which collectively promote the acquisition of tumor/glioma traits by human astrocytes and glial progenitor cells as that promoting high proliferation and apoptosis evasion.
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