RESUMEN
Glioblastoma multiforme (GBM) is a fatal brain tumor without effective drug treatment. In this study, we highlight, for the first time, the contribution of chromatin remodeling gene Lysine (K)-specific demethylase 5C (KDM5C) in GBM via an extensive analysis of clinical, expression, and functional data, integrated with publicly available omic datasets. The expression analysis on GBM samples (N = 37) revealed two informative subtypes, namely KDM5CHigh and KDM5CLow, displaying higher/lower KDM5C levels compared to the controls. The former subtype displays a strong downregulation of brain-derived neurotrophic factor (BDNF)-a negative KDM5C target-and a robust overexpression of hypoxia-inducible transcription factor-1A (HIF1A) gene, a KDM5C modulator. Additionally, a significant co-expression among the prognostic markers HIF1A, Survivin, and p75 was observed. These results, corroborated by KDM5C overexpression and hypoxia-related functional assays in T98G cells, suggest a role for the HIF1A-KDM5C axis in the hypoxic response in this tumor. Interestingly, fluorescence-guided surgery on GBM sections further revealed higher KDM5C and HIF1A levels in the tumor rim niche compared to the adjacent tumor margin, indicating a regionally restricted hyperactivity of this regulatory axis. Analyzing the TCGA expression and methylation data, we found methylation changes between the subtypes in the genes, accounting for the hypoxia response, stem cell differentiation, and inflammation. High NANOG and IL6 levels highlight a distinctive stem cell-like and proinflammatory signature in the KDM5CHigh subgroup and GBM niches. Taken together, our results indicate HIF1A-KDM5C as a new, relevant cancer axis in GBM, opening a new, interesting field of investigation based on KDM5C as a potential therapeutic target of the hypoxic microenvironment in GBM.
Asunto(s)
Neoplasias Encefálicas , Glioblastoma , Neoplasias Encefálicas/metabolismo , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Línea Celular Tumoral , Cromatina/genética , Regulación Neoplásica de la Expresión Génica , Glioblastoma/metabolismo , Histona Demetilasas/genética , Histona Demetilasas/metabolismo , Humanos , Hipoxia/genética , Interleucina-6/metabolismo , Lisina/metabolismo , Oxígeno/metabolismo , Survivin/genética , Factores de Transcripción/metabolismo , Microambiente Tumoral/genéticaRESUMEN
BACKGROUND: Primary central nervous system sarcomas are rare primitive mesenchymal non-meningothelial tumors. Malignant peripheral nerve sheath tumor accounts for 5% of sarcomas, with an incidence of approximately 0.001% and a recognized association with neurofibromatosis type 1. Its intracranial subtype, the so-called malignant intracerebral nerve sheath tumor (MINST), is even more infrequent. Current knowledge about its clinical presentation and best therapeutic management is poor because of the limited number of cases reported in literature. Commonly, intratumoral hemorrhage occurs at the time of diagnosis and, notably, most patients had intracranial hemorrhage prior to definitive diagnosis. CASE DESCRIPTION: We report a case of MINST in a young boy affected by neurofibromatosis type 1 who presented a spontaneous intracranial hemorrhage, successfully treated with surgery and postoperative adjuvant therapy. The tumor relapsed 1 year after and was successfully retreated with a second surgery. CONCLUSIONS: Malignant intracerebral nerve sheath tumors are rare sarcomas that can be associated with intratumoral hemorrhage at the time of presentation, mostly in patients with neurofibromatosis type 1. Surgery promptly performed, associated with adjuvant therapy, can result in an encouraging survival rate.
Asunto(s)
Hemorragias Intracraneales/etiología , Neoplasias de la Vaina del Nervio/complicaciones , Neoplasias de la Vaina del Nervio/cirugía , Sarcoma/complicaciones , Sarcoma/cirugía , Adolescente , Quimioradioterapia , Terapia Combinada , Angiografía por Tomografía Computarizada , Humanos , Hemorragias Intracraneales/diagnóstico por imagen , Hemorragias Intracraneales/cirugía , Imagen por Resonancia Magnética , Masculino , Recurrencia Local de Neoplasia/cirugía , Neurofibromatosis 1/complicaciones , Procedimientos Neuroquirúrgicos , Resultado del TratamientoRESUMEN
Glioblastoma multiforme (GBM) is one of the most deadly types of cancer. To date, the best clinical approach for treatment is based on administration of temozolomide (TMZ) in combination with radiotherapy. Much evidence suggests that the intracellular level of the alkylating enzyme O(6)-methylguanine-DNA methyltransferase (MGMT) impacts response to TMZ in GBM patients. MGMT expression is regulated by the methylation of its promoter. However, evidence indicates that this is not the only regulatory mechanism present. Here, we describe a hitherto unknown microRNA-mediated mechanism of MGMT expression regulation. We show that miR-221 and miR-222 are upregulated in GMB patients and that these paralogues target MGMT mRNA, inducing greater TMZ-mediated cell death. However, miR-221/miR-222 also increase DNA damage and, thus, chromosomal rearrangements. Indeed, miR-221 overexpression in glioma cells led to an increase in markers of DNA damage, an effect rescued by re-expression of MGMT. Thus, chronic miR-221/222-mediated MGMT downregulation may render cells unable to repair genetic damage. This, associated also to miR-221/222 oncogenic potential, may poor GBM prognosis.