RESUMEN
Glioblastoma stem cells (GSCs) are implicated in tumor neovascularization, invasiveness, and therapeutic resistance. To illuminate mechanisms governing these hallmark features, we developed a de novo glioblastoma multiforme (GBM) model derived from immortalized human neural stem/progenitor cells (hNSCs) to enable precise system-level comparisons of pre-malignant and oncogene-induced malignant states of NSCs. Integrated transcriptomic and epigenomic analyses uncovered a PAX6/DLX5 transcriptional program driving WNT5A-mediated GSC differentiation into endothelial-like cells (GdECs). GdECs recruit existing endothelial cells to promote peritumoral satellite lesions, which serve as a niche supporting the growth of invasive glioma cells away from the primary tumor. Clinical data reveal higher WNT5A and GdECs expression in peritumoral and recurrent GBMs relative to matched intratumoral and primary GBMs, respectively, supporting WNT5A-mediated GSC differentiation and invasive growth in disease recurrence. Thus, the PAX6/DLX5-WNT5A axis governs the diffuse spread of glioma cells throughout the brain parenchyma, contributing to the lethality of GBM.
Asunto(s)
Glioblastoma/genética , Glioblastoma/patología , Invasividad Neoplásica/genética , Proteína Wnt-5a/genética , Células Endoteliales/citología , Células Endoteliales/metabolismo , Epigenómica , Regulación Neoplásica de la Expresión Génica , Proteínas de Homeodominio/metabolismo , Humanos , Células-Madre Neurales/metabolismo , Factor de Transcripción PAX6/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Factores de Transcripción/metabolismoRESUMEN
An integrated genomic and functional analysis to elucidate DNA damage signaling factors promoting self-renewal of glioma stem cells (GSCs) identified proliferating cell nuclear antigen (PCNA)-associated factor (PAF) up-regulation in glioblastoma. PAF is preferentially overexpressed in GSCs. Its depletion impairs maintenance of self-renewal without promoting differentiation and reduces tumor-initiating cell frequency. Combined transcriptomic and metabolomic analyses revealed that PAF supports GSC maintenance, in part, by influencing DNA replication and pyrimidine metabolism pathways. PAF interacts with PCNA and regulates PCNA-associated DNA translesion synthesis (TLS); consequently, PAF depletion in combination with radiation generated fewer tumorspheres compared with radiation alone. Correspondingly, pharmacological impairment of DNA replication and TLS phenocopied the effect of PAF depletion in compromising GSC self-renewal and radioresistance, providing preclinical proof of principle that combined TLS inhibition and radiation therapy may be a viable therapeutic option in the treatment of glioblastoma multiforme (GBM).
Asunto(s)
Neoplasias Encefálicas/radioterapia , Proteínas Portadoras/genética , Glioblastoma/radioterapia , Células Madre Neoplásicas/efectos de la radiación , Animales , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/patología , Proteínas Portadoras/metabolismo , Daño del ADN/genética , Daño del ADN/efectos de la radiación , Reparación del ADN/genética , Reparación del ADN/efectos de la radiación , Replicación del ADN/efectos de los fármacos , Proteínas de Unión al ADN , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de la radiación , Glioblastoma/genética , Glioblastoma/mortalidad , Glioblastoma/patología , Proteínas Fluorescentes Verdes/genética , Humanos , Ratones SCID , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/patología , Pirimidinas/biosíntesis , Tolerancia a Radiación , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Myelodysplastic syndrome (MDS) risk correlates with advancing age, therapy-induced DNA damage, and/or shorter telomeres, but whether telomere erosion directly induces MDS is unknown. Here, we provide the genetic evidence that telomere dysfunction-induced DNA damage drives classical MDS phenotypes and alters common myeloid progenitor (CMP) differentiation by repressing the expression of mRNA splicing/processing genes, including SRSF2. RNA-seq analyses of telomere dysfunctional CMP identified aberrantly spliced transcripts linked to pathways relevant to MDS pathogenesis such as genome stability, DNA repair, chromatin remodeling, and histone modification, which are also enriched in mouse CMP haploinsufficient for SRSF2 and in CD34(+) CMML patient cells harboring SRSF2 mutation. Together, our studies establish an intimate link across telomere biology, aberrant RNA splicing, and myeloid progenitor differentiation.
Asunto(s)
Diferenciación Celular/genética , Hematopoyesis/genética , Síndromes Mielodisplásicos/genética , Telómero , Animales , Haploinsuficiencia , Humanos , Ratones , Síndromes Mielodisplásicos/patología , Proteínas Nucleares/genética , Empalme del ARN , Ribonucleoproteínas/genética , Factores de Empalme Serina-ArgininaRESUMEN
AIM: Studies on Helicobacter pylori (H pylori) and gastroduodenal diseases have focused mainly on the distal sites of the stomach, but relationship with the gastric cardia is lacking. The aim of this study is to determine if the gastric topology and genotypic distribution of H pylori were associated with different upper gastrointestinal pathologies in a multiethnic Asian population. METHODS: Gastric biopsies from the cardia, body/corpus and antrum were endoscoped from a total of 155 patients with dyspepsia and/or reflux symptoms, with informed consent. H pylori isolates obtained were tested for the presence of 26 kDa, ureC, cagA, vacA, iceA1, iceA2 and babA2 genes using PCR while DNA fingerprints were generated using random amplification polymorphic DNA (RAPD). RESULTS: H pylori was present in 51/155 (33%) of patients studied. Of these, 16, 15 and 20 were isolated from patients with peptic ulcer diseases, gastroesophageal reflux diseases and non-ulcer dyspepsia, respectively. Of the H pylori positive patients, 75% (38/51) had H pylori in all three gastric sites. The prevalence of various genes in the H pylori isolates was shown to be similar irrespective of their colonization sites as well as among the same site of different patients. The RAPD profiles of H pylori isolates from different gastric sites were highly similar among intra-patients but varied greatly between different patients. CONCLUSION: Topographic colonization of H pylori and the virulence genes harboured by these isolates have no direct bearing to the clinical state of the patients. In multi-ethnic Singapore, the stomach of each patient is colonized by a predominant strain of H pylori, irrespective of the clinical diagnosis.