RESUMO
The mechanisms underlying stimuli-induced dynamic structural remodeling of RNAs for the maintenance of cellular physiological function and survival remain unclear. Here, we showed that in MGMT promoter-methylated glioblastoma (GBM), the RNA helicase DEAD-box helicase 46 (DDX46) is phosphorylated by temozolomide (TMZ)-activated checkpoint kinase 1 (CHK1), resulting in a dense-to-loose conformational change and an increase in DDX46 helicase activity. DDX46-mediated tertiary structural remodeling of LINC01956 exposes the binding motifs of LINC01956 to the 3' untranslated region of O6-methylguanine DNA methyltransferase (MGMT). This accelerates recruitment of MGMT mRNA to the RNA export machinery and transportation of MGMT mRNA from the nucleus to the cytoplasm, leading to increased MGMT abundance and TMZ resistance. Using patient-derived xenograft (PDX) and tumor organoid models, we found that treatment with the CHK1 inhibitor SRA737abolishes TMZ-induced structural remodeling of LINC01956 and subsequent MGMT up-regulation, resensitizing TMZ-resistant MGMT promoter-methylated GBM to TMZ. In conclusion, these findings highlight a mechanism underlying temozolomide-induced RNA structural remodeling and may represent a potential therapeutic strategy for patients with TMZ-resistant MGMT promoter-methylated GBM.
Assuntos
RNA Helicases DEAD-box , Metilases de Modificação do DNA , Resistencia a Medicamentos Antineoplásicos , Glioblastoma , RNA Longo não Codificante , Temozolomida , Proteínas Supressoras de Tumor , Glioblastoma/genética , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Glioblastoma/metabolismo , Temozolomida/farmacologia , Temozolomida/uso terapêutico , Humanos , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Animais , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/genética , RNA Helicases DEAD-box/metabolismo , RNA Helicases DEAD-box/genética , Metilases de Modificação do DNA/metabolismo , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Enzimas Reparadoras do DNA/genética , Regiões Promotoras Genéticas/genética , Metilação de DNA/genética , Metilação de DNA/efeitos dos fármacos , Quinase 1 do Ponto de Checagem/metabolismo , Quinase 1 do Ponto de Checagem/genética , Linhagem Celular Tumoral , Camundongos , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Fosforilação/efeitos dos fármacosRESUMO
BACKGROUND/AIM: To investigate the significance of the timing of chemoradiotherapy together with clinical and laboratory features in newly diagnosed glioblastoma. PATIENTS AND METHODS: Clinical and laboratory parameters of 209 patients with glioblastoma potentially influencing overall (OS) and progression-free (PFS) survival were analyzed in univariable and multivariable models. RESULTS: On univariable analyses, Karnofsky performance status (p<0.001), recursive partitioning analysis (RPA) class (p<0.001), O6-methylguanine-DNA methyltransferase (MGMT)-status (p<0.001), extent of resection (p<0.001), radiotherapy dose (p=0.01), and the number of adjuvant temozolomide (TMZ) cycles (p<0.001) were significantly associated with OS. Additionally, MGMT-status (p<0.001), extent of resection (p=0.03), surgical site infections (p=0.02), and the number of adjuvant TMZ cycles (p<0.001) were significantly associated with PFS. Multivariable analysis identified radiotherapy dose as the only independent predictor (p=0.049) of OS. MGMT-status (p=0.02) and the number of adjuvant TMZ cycles (p<0.001) were independent predictors of PFS. CONCLUSION: The timing of chemoradiotherapy did not play a prognostic role. For OS, the radiotherapy dose, and for PFS, MGMT-status and the number of adjuvant TMZ cycles were identified as independent prognostic factors.
Assuntos
Neoplasias Encefálicas , Quimiorradioterapia , Glioblastoma , Temozolomida , Humanos , Glioblastoma/terapia , Glioblastoma/mortalidade , Feminino , Masculino , Pessoa de Meia-Idade , Quimiorradioterapia/métodos , Idoso , Adulto , Prognóstico , Neoplasias Encefálicas/terapia , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/tratamento farmacológico , Temozolomida/uso terapêutico , Adulto Jovem , Idoso de 80 Anos ou mais , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismo , Fatores de Tempo , Intervalo Livre de Progressão , Proteínas Supressoras de Tumor , Enzimas Reparadoras do DNARESUMO
Glioblastoma (GBM) is one of the most aggressive malignant tumors of the brain. We queried PubMed for articles about molecular predictor markers in GBM. This scoping review aims to analyze the most important outcome predictors in patients with GBM and to compare these factors in terms of absolute months of survival benefit and percentages. Performing a gross total resection for patients with GBM undergoing optimal chemo- and radiotherapy provides a significant benefit in overall survival compared to those patients who received a subtotal or partial resection. However, compared to IDH-Wildtype GBMs, patients with IDH-Mutant 1/2 GBMs have an increased survival. MGMT promoter methylation status is another strong outcome predictor for patients with GBM. In the reviewed literature, patients with methylated MGMT promoter lived approximately 50% to 90% longer than those with an unmethylated MGMT gene promoter. Moreover, KPS is an important predictor of survival and quality of life, demonstrating that we should refrain from aggressive surgery in important brain areas. As new therapies (such as TTFs) emerge, we are optimistic that the overall median survival will increase, even for IDH-Wildtype GBMs. In conclusion, molecular profiles are stronger outcome predictors than the extent of neurosurgical resection for GBM.
Assuntos
Neoplasias Encefálicas , Glioblastoma , Imageamento por Ressonância Magnética , Humanos , Glioblastoma/genética , Glioblastoma/cirurgia , Glioblastoma/diagnóstico por imagem , Glioblastoma/patologia , Glioblastoma/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/cirurgia , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismo , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Biomarcadores Tumorais/genética , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Prognóstico , Metilação de DNA , Isocitrato Desidrogenase/genética , Mutação , Regiões Promotoras GenéticasRESUMO
Overcoming temozolomide (TMZ)-resistance is a major challenge in glioblastoma therapy. Therefore, identifying the key molecular player in chemo-resistance becomes urgent. We previously reported the downregulation of PDCD10 in primary glioblastoma patients and its tumor suppressor-like function in glioblastoma cells. Here, we demonstrate that the loss of PDCD10 causes a significant TMZ-resistance during treatment and promotes a rapid regrowth of tumor cells after treatment. PDCD10 knockdown upregulated MGMT, a key enzyme mediating chemo-resistance in glioblastoma, accompanied by increased expression of DNA mismatch repair genes, and enabled tumor cells to evade TMZ-induced cell-cycle arrest. These findings were confirmed in independent models of PDCD10 overexpressing cells. Furthermore, PDCD10 downregulation led to the dedifferentiation of glioblastoma cells, as evidenced by increased clonogenic growth, the upregulation of glioblastoma stem cell (GSC) markers, and enhanced neurosphere formation capacity. GSCs derived from PDCD10 knockdown cells displayed stronger TMZ-resistance and regrowth potency, compared to their parental counterparts, indicating that PDCD10-induced stemness may independently contribute to tumor malignancy. These data provide evidence for a dual role of PDCD10 in tumor suppression by controlling both chemo-resistance and dedifferentiation, and highlight PDCD10 as a potential prognostic marker and target for combination therapy with TMZ in glioblastoma.
Assuntos
Proteínas Reguladoras de Apoptose , Resistencia a Medicamentos Antineoplásicos , Glioblastoma , Temozolomida , Humanos , Glioblastoma/patologia , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/tratamento farmacológico , Temozolomida/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Linhagem Celular Tumoral , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas Reguladoras de Apoptose/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/tratamento farmacológico , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas/genética , Proliferação de Células/efeitos dos fármacos , Metilases de Modificação do DNA/metabolismo , Metilases de Modificação do DNA/genética , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/genética , Enzimas Reparadoras do DNA/metabolismo , Enzimas Reparadoras do DNA/genéticaRESUMO
Paracoccus denitrificans has been identified as a representative strain with heterotrophic nitrification-aerobic denitrification capabilities (HN-AD), and demonstrates strong denitrification proficiency. Previously, we isolated the DYTN-1 strain from activated sludge, and it has showcased remarkable nitrogen removal abilities and genetic editability, which positions P. denitrificans DYTN-1 as a promising chassis cell for synthetic biology engineering, with versatile pollutant degradation capabilities. However, the strain's low stability in plasmid conjugation transfer efficiency (PCTE) hampers gene editing efficacy, and is attributed to its restriction modification system (R-M system). To overcome this limitation, we characterized the R-M system in P. denitrificans DYTN-1 and identified a DNA endonuclease and 13 DNA methylases, with the DNA endonuclease identified as HNH endonuclease. Subsequently, we developed a plasmid artificial modification approach to enhance conjugation transfer efficiency, which resulted in a remarkable 44-fold improvement in single colony production. This was accompanied by an increase in the frequency of positive colonies from 33.3% to 100%. Simultaneously, we cloned, expressed, and characterized the speculative HNH endonuclease capable of degrading unmethylated DNA at 30°C without specific cutting site preference. Notably, the impact of DNA methylase M9 modification on the plasmid was discovered, significantly impeding the cutting efficiency of the HNH endonuclease. This revelation unveils a novel R-M system in P. denitrificans and sheds light on protective mechanisms employed against exogenous DNA invasion. These findings pave the way for future engineering endeavors aimed at enhancing the DNA editability of P. denitrificans.
Assuntos
Conjugação Genética , Desnitrificação , Paracoccus denitrificans , Plasmídeos , Plasmídeos/genética , Paracoccus denitrificans/genética , Paracoccus denitrificans/metabolismo , Edição de Genes/métodos , Endonucleases/genética , Endonucleases/metabolismo , Nitrificação , Enzimas de Restrição-Modificação do DNA/genética , Enzimas de Restrição-Modificação do DNA/metabolismo , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismoRESUMO
The precise regulation of transcription is required for embryonic development, adult tissue turnover, and regeneration. Epigenetic modifications play a crucial role in orchestrating and regulating the transcription of genes. These modifications are important in the transition of pluripotent stem cells and their progeny. Methylation, a key epigenetic modification, influences gene expression through changes in DNA methylation. Work in different organisms has shown that the DNA methyltransferase-1-associated protein (DMAP1) may associate with other molecules to repress transcription through DNA methylation. Thus, DMAP1 is a versatile protein implicated in a myriad of events, including pluripotency maintenance, DNA damage repair, and tumor suppression. While DMAP1 has been extensively studied in vitro, its complex regulation in the context of the adult organism remains unclear. To gain insights into the possible roles of DMAP1 at the organismal level, we used planarian flatworms that possess remarkable regenerative capabilities driven by pluripotent stem cells called neoblast. Our findings demonstrate the evolutionary conservation of DMAP1 in the planarian Schmidtea mediterranea. Functional disruption of DMAP1 through RNA interference revealed its critical role in tissue maintenance, neoblast differentiation, and regeneration in S. mediterranea. Moreover, our analysis unveiled a novel function for DMAP1 in regulating cell death in response to DNA damage and influencing the expression of axial polarity markers. Our findings provide a simplified paradigm for studying DMAP1's function in adult tissues.
Assuntos
Planárias , Regeneração , Animais , Planárias/genética , Planárias/fisiologia , Regeneração/fisiologia , Regeneração/genética , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Metilação de DNA/genética , Interferência de RNA , Células-Tronco Pluripotentes/metabolismo , Epigênese Genética , Regulação da Expressão Gênica no Desenvolvimento , Metilases de Modificação do DNA/metabolismo , Metilases de Modificação do DNA/genética , Proteínas de Helminto/metabolismo , Proteínas de Helminto/genéticaRESUMO
Temozolomide (TMZ) resistance is a major challenge in the treatment of glioblastoma (GBM). Tumour reproductive cells (TRCs) have been implicated in the development of chemotherapy resistance. By culturing DBTRG cells in three-dimensional soft fibrin gels to enrich GBM TRCs and performing RNA-seq analysis, the expression of stanniocalcin-1 (STC), a gene encoding a secreted glycoprotein, was found to be upregulated in TRCs. Meanwhile, the viability of TMZ-treated TRC cells was significantly higher than that of TMZ-treated 2D cells. Analysis of clinical data from CGGA (Chinese Glioma Genome Atlas) database showed that high expression of STC1 was closely associated with poor prognosis, glioma grade and resistance to TMZ treatment, suggesting that STC1 may be involved in TMZ drug resistance. The expression of STC1 in tissues and cells was examined, as well as the effect of STC1 on GBM cell proliferation and TMZ-induced DNA damage. The results showed that overexpression of STC1 promoted and knockdown of STC1 inhibited TMZ-induced DNA damage. These results were validated in an intracranial tumour model. These data revealed that STC1 exerts regulatory functions on MGMT expression in GBM, and provides a rationale for targeting STC1 to overcome TMZ resistance.
Assuntos
Neoplasias Encefálicas , Resistencia a Medicamentos Antineoplásicos , Regulação Neoplásica da Expressão Gênica , Glioblastoma , Glicoproteínas , Temozolomida , Animais , Feminino , Humanos , Masculino , Camundongos , Antineoplásicos Alquilantes/farmacologia , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Dano ao DNA , Metilases de Modificação do DNA/metabolismo , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Glicoproteínas/metabolismo , Glicoproteínas/genética , Temozolomida/farmacologia , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoAssuntos
Metilases de Modificação do DNA , Enzimas Reparadoras do DNA , Resistencia a Medicamentos Antineoplásicos , Glioblastoma , Células-Tronco Neoplásicas , Temozolomida , Regulação para Cima , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/patologia , Temozolomida/uso terapêutico , Temozolomida/farmacologia , Humanos , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Metilases de Modificação do DNA/metabolismo , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Regulação para Cima/efeitos dos fármacos , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Antineoplásicos Alquilantes/uso terapêutico , Antineoplásicos Alquilantes/farmacologiaRESUMO
OBJECTIVES: High-grade gliomas (HGGs) are highly malignant, aggressive, and have a high incidence and mortality rate. The aim of this study was to investigate survival outcomes and prognostic factors in patients with HGGs. METHODS: In this retrospective study, a total of 159 patients with histologically confirmed HGGs were included. The recruitment period was from January 2011 to December 2019. We evaluated patient demographic data, tumor characteristics, treatment methods, immunocytochemistry results, overall survival (OS) time, and progression-free survival (PFS) time using Kaplan-<>Meier survival analysis with log-rank testing. Additionally, we employed Cox regression analysis to identify independent factors associated with survival outcomes. RESULTS: Kaplan-Meier survival analysis revealed that the 1-, 2-, and 5-years OS rates were 81.8%, 50.3%, and 12.6%, respectively. Similarly, the 1-, 2-, and 5-years PFS rates were 50.9%, 22.4%, and 3.1%, respectively. The median OS duration was 35.0 months. The univariate analysis indicated that postoperative pathological classification, grade, and age were significantly associated with patient outcomes (p < 0.01). Among the patients, 147 received concurrent chemoradiotherapy, while 12 did not. The immunohistochemical markers of ki-67, MGMT, IDH1R132H, and p53 demonstrated statistically significant differences in their prognostic impact (p = 0.001, p = 0.020, p = 0.003, and p = 0.021, respectively). In conclusion, we found that grades, age, pathological classification, ki-67, MGMT, and IDH1R132H expression were statistically significantly associated with PFS (p < 0.01, p = 0.004, p = 0.003, p = 0.001, p = 0.036, and p = 0.028). Additionally, immunohistochemical expressions of TRIB3 and AURKA were significantly higher in patients with shorter survival (p = 0.015 and p = 0.023). CONCLUSIONS: Tumor grade and the use of concurrent chemoradiotherapy after surgery were independent prognostic factors that significantly influenced patient survival. Additionally, tumor grade and MGMT expression were found to be independent factors affecting progression-free survival (PFS). Notably, the expression of TRIB3 and AURKA was higher in patients with poor survival outcomes.
Assuntos
Neoplasias Encefálicas , Glioma , Gradação de Tumores , Humanos , Feminino , Masculino , Glioma/mortalidade , Glioma/patologia , Glioma/terapia , Glioma/metabolismo , Estudos Retrospectivos , Pessoa de Meia-Idade , Adulto , Prognóstico , Idoso , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/terapia , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/metabolismo , Quimiorradioterapia , Adulto Jovem , Estimativa de Kaplan-Meier , Biomarcadores Tumorais/metabolismo , Intervalo Livre de Progressão , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismo , Análise Multivariada , Proteínas Supressoras de Tumor/metabolismo , Taxa de Sobrevida , Adolescente , Enzimas Reparadoras do DNA/metabolismo , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/análiseRESUMO
It is well known how the precise localization of glioblastoma multiforme (GBM) predicts the direction of tumor spread in the surrounding neuronal structures. The aim of the present review is to reveal the lateralization of GBM by evaluating the anatomical regions where it is frequently located as well as the main molecular alterations observed in different brain regions. According to the literature, the precise or most frequent lateralization of GBM has yet to be determined. However, it can be said that GBM is more frequently observed in the frontal lobe. Tractus and fascicles involved in GBM appear to be focused on the corticospinal tract, superior longitudinal I, II and III fascicles, arcuate fascicle long segment, frontal strait tract, and inferior frontooccipital fasciculus. Considering the anatomical features of GBM and its brain involvement, it is logical that the main brain regions involved are the frontaltemporalparietaloccipital lobes, respectively. Although tumor volumes are higher in the right hemisphere, it has been determined that the prognosis of patients diagnosed with cancer in the left hemisphere is worse, probably reflecting the anatomical distribution of some detrimental alterations such as TP53 mutations, PTEN loss, EGFR amplification, and MGMT promoter methylation. There are theories stating that the right hemisphere is less exposed to external influences in its development as it is responsible for the functions necessary for survival while tumors in the left hemisphere may be more aggressive. To shed light on specific anatomical and molecular features of GBM in different brain regions, the present review article is aimed at describing the main lateralization pathways as well as gene mutations or epigenetic modifications associated with the development of brain tumors.
Assuntos
Neoplasias Encefálicas , Glioblastoma , Humanos , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Glioblastoma/genética , Glioblastoma/patologia , Glioblastoma/metabolismo , Receptores ErbB/genética , Receptores ErbB/metabolismo , Mutação , Glioma/genética , Glioma/patologia , Glioma/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Prognóstico , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismoRESUMO
This study investigated the role of O6-methylguanine-DNA methyltransferase promoter (MGMTp) methylation hierarchy and heterogeneity in grade 2-3 gliomas, focusing on variations in chemotherapy benefits and resection dependency. A cohort of 668 newly diagnosed grade 2-3 gliomas, with comprehensive clinical, radiological, and molecular data, formed the basis of this analysis. The extent of resection was categorized into gross total resection (GTR ≥100%), subtotal resection (STR >90%), and partial resection (PR ≤90%). MGMTp methylation levels were examined using quantitative pyrosequencing. Our findings highlighted the critical role of GTR in improving the prognosis for astrocytomas (IDH1/2-mutant and 1p/19q non-codeleted), contrasting with its lesser significance for oligodendrogliomas (IDH1/2 mutation and 1p/19q codeletion). Oligodendrogliomas demonstrated the highest average MGMTp methylation levels (median: 28%), with a predominant percentage of methylated cases (average methylation levels >20%). Astrocytomas were more common in the low-methylated group (10%-20%), while IDH wild-type gliomas were mostly unmethylated (<10%). Spatial distribution analysis revealed a decrement in frontal lobe involvement from methylated, low-methylated to unmethylated cases (72.8%, 59.3%, and 47.8%, respectively). In contrast, low-methylated and unmethylated cases were more likely to invade the temporal-insular region (19.7%, 34.3%, and 40.4%, respectively). Astrocytomas with intermediate MGMTp methylation were notably associated with temporal-insular involvement, potentially indicating a moderate response to temozolomide and underscoring the importance of aggressive resection strategies. In conclusion, our study elucidates the complex interplay of MGMTp methylation hierarchy and heterogeneity among grade 2-3 gliomas, providing insights into why astrocytomas and IDH wild-type lower-grade glioma might derive less benefit from chemotherapy.
Assuntos
Neoplasias Encefálicas , Metilação de DNA , Glioma , Gradação de Tumores , Regiões Promotoras Genéticas , Humanos , Regiões Promotoras Genéticas/genética , Masculino , Feminino , Pessoa de Meia-Idade , Glioma/genética , Glioma/patologia , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Adulto , Idoso , Isocitrato Desidrogenase/genética , Mutação , Oligodendroglioma/genética , Oligodendroglioma/patologia , O(6)-Metilguanina-DNA Metiltransferase/genética , O(6)-Metilguanina-DNA Metiltransferase/metabolismo , Prognóstico , Organização Mundial da Saúde , Enzimas Reparadoras do DNA/genética , Proteínas Supressoras de Tumor/genética , Adulto Jovem , Astrocitoma/genética , Astrocitoma/patologia , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismoRESUMO
The prognosis of patients with osteosarcoma who experience recurrence or progression (R/P) is extremely poor, and more effective and less toxic therapies are needed. In the current study, the clinical data of osteosarcoma patients who experienced R/P were retrospectively analyzed to verify the reliability of O-6-methylguanine-DNA methyltransferase (MGMT) protein expression or MGMT promoter methylation for predicting the response to off-label temozolomide (TMZ)-containing chemotherapy. Of the 30 evaluable patients, 9 (30%) showed no/low MGMT protein expression, whereas all 16 evaluable patients had unmethylated MGMT promoter irrespective of MGMT protein expression levels. Twenty-three patients received TMZ-containing chemotherapy for measurable lesions (n = 14) or as adjuvant therapy following resection of recurrent lesions (n = 9). Among 14 patients with radiologically measurable lesions, the objective response rate was higher in the MGMT no/low-expression group (50.0%) than in the MGMT intermediate/high-expression group with borderline significance (0%, p = 0.066). The 6-month progression-free survival (PFS) rate in patients with radiologically measurable lesions was significantly higher in the MGMT no/low-expression group (50.0%) than in the MGMT intermediate/high-expression group (0%, p = 0.036). In the multivariate analysis of the 23 patients receiving TMZ-containing chemotherapy, MGMT expression and disease status before TMZ-containing chemotherapy were significantly associated with PFS. No severe adverse effects were observed during TMZ-containing chemotherapy. MGMT protein expression, but not MGMT promoter methylation, could predict a favorable outcome in patients receiving TMZ-containing chemotherapy.
Assuntos
Biomarcadores Tumorais , Neoplasias Ósseas , Metilação de DNA , Metilases de Modificação do DNA , Enzimas Reparadoras do DNA , Osteossarcoma , Regiões Promotoras Genéticas , Temozolomida , Proteínas Supressoras de Tumor , Humanos , Osteossarcoma/tratamento farmacológico , Osteossarcoma/genética , Osteossarcoma/mortalidade , Osteossarcoma/patologia , Temozolomida/uso terapêutico , Feminino , Masculino , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Adulto , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismo , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/genética , Neoplasias Ósseas/patologia , Neoplasias Ósseas/mortalidade , Adolescente , Adulto Jovem , Estudos Retrospectivos , Criança , Prognóstico , Antineoplásicos Alquilantes/uso terapêutico , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologiaRESUMO
O6-methylguanine DNA methyltransferase (MGMT) removes alkyl adducts from the guanine O6 position (O6-MG) and repairs DNA damage. High MGMT expression results in poor response to temozolomide (TMZ). However, the biological importance of MGMT and the mechanism underlying its high expression in pancreatic neuroendocrine tumors (PanNETs) remain elusive. Here, it is found that MGMT expression is highly elevated in PanNET tissues compared with paired normal tissues and negatively associated with progression-free survival (PFS) time in patients with PanNETs. Knocking out MGMT inhibits cancer cell growth in vitro and in vivo. Ectopic MEN1 expression suppresses MGMT transcription in a manner that depends on ß-Catenin nuclear export and degradation. The Leucine 267 residue of MEN1 is crucial for regulating ß-Catenin-MGMT axis activation and chemosensitivity to TMZ. Interference with ß-Catenin re-sensitizes tumor cells to TMZ and significantly reduces the cytotoxic effects of high-dose TMZ treatment, and MGMT overexpression counteracts the effects of ß-Catenin deficiency. This study reveals the biological importance of MGMT and a new mechanism by which MEN1 deficiency regulates its expression, thus providing a potential combinational strategy for treating patients with TMZ-resistant PanNETs.
Assuntos
Metilases de Modificação do DNA , Enzimas Reparadoras do DNA , Resistencia a Medicamentos Antineoplásicos , Tumores Neuroendócrinos , Neoplasias Pancreáticas , Temozolomida , beta Catenina , Animais , Feminino , Humanos , Masculino , Camundongos , Antineoplásicos Alquilantes/farmacologia , beta Catenina/metabolismo , beta Catenina/genética , Linhagem Celular Tumoral , Modelos Animais de Doenças , Metilases de Modificação do DNA/metabolismo , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Camundongos Nus , Tumores Neuroendócrinos/genética , Tumores Neuroendócrinos/tratamento farmacológico , Tumores Neuroendócrinos/metabolismo , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas/genética , Temozolomida/farmacologia , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
Glioblastoma (GBM) presents a daunting challenge due to its resistance to temozolomide (TMZ), a hurdle exacerbated by the proneural-to-mesenchymal transition (PMT) from a proneural (PN) to a mesenchymal (MES) phenotype. TAGLN2 is prominently expressed in GBM, particularly in the MES subtype compared to low-grade glioma (LGG) and the PN subtype. Our research reveals TAGLN2's involvement in PMT and TMZ resistance through a series of in vitro and in vivo experiments. TAGLN2 knockdown can restrain proliferation and invasion, trigger DNA damage and apoptosis, and heighten TMZ sensitivity in GBM cells. Conversely, elevating TAGLN2 levels amplifies resistance to TMZ in cellular and intracranial xenograft mouse models. We demonstrate the interaction relationship between TAGLN2 and ERK1/2 through co-immunoprecipitation (Co-IP) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) spectrometry analysis. Knockdown of TAGLN2 results in a decrease in the expression of p-ERK1/2, whereas overexpression of TAGLN2 leads to an increase in p-ERK1/2 expression within the nucleus. Subsequently, the regulatory role of TAGLN2 in the expression and control of MGMT has been demonstrated. Finally, the regulation of TAGLN2 by NF-κB has been validated through chromatin immunoprecipitation and ChIP-PCR assays. In conclusion, our results confirm that TAGLN2 exerts its biological functions by interacting with the ERK/MGMT axis and being regulated by NF-κB, thereby facilitating the acquisition of promoting PMT and increased resistance to TMZ therapy in glioblastoma. These results provide valuable insights for the advancement of targeted therapeutic approaches to overcome TMZ resistance in clinical treatments.
Assuntos
Antineoplásicos Alquilantes , Neoplasias Encefálicas , Resistencia a Medicamentos Antineoplásicos , Glioblastoma , Temozolomida , Animais , Humanos , Camundongos , Antineoplásicos Alquilantes/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Metilases de Modificação do DNA/metabolismo , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glioblastoma/patologia , Glioblastoma/genética , Glioblastoma/tratamento farmacológico , Glioblastoma/metabolismo , Camundongos Nus , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Temozolomida/farmacologia , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Glioblastoma (GBM) is a highly aggressive brain tumor associated with poor patient survival. The current standard treatment involves invasive surgery, radiotherapy, and chemotherapy employing temozolomide (TMZ). Resistance to TMZ is, however, a major challenge. Previous work from our group has identified candidate genes linked to TMZ resistance, including genes encoding translesion synthesis (TLS) DNA polymerases iota (PolÉ©) and kappa (Polκ). These specialized enzymes are known for bypassing lesions and tolerating DNA damage. Here, we investigated the roles of PolÉ© and Polκ in TMZ resistance, employing MGMT-deficient U251-MG glioblastoma cells, with knockout of either POLI or POLK genes encoding PolÉ© and Polκ, respectively, and assess their viability and genotoxic stress responses upon subsequent TMZ treatment. Cells lacking either of these polymerases exhibited a significant decrease in viability following TMZ treatment compared to parental counterparts. The restoration of the missing polymerase led to a recovery of cell viability. Furthermore, knockout cells displayed increased cell cycle arrest, mainly in late S-phase, and lower levels of genotoxic stress after TMZ treatment, as assessed by a reduction of γH2AX foci and flow cytometry data. This implies that TMZ treatment does not trigger a significant H2AX phosphorylation response in the absence of these proteins. Interestingly, combining TMZ with Mirin (double-strand break repair pathway inhibitor) further reduced the cell viability and increased DNA damage and γH2AX positive cells in TLS KO cells, but not in parental cells. These findings underscore the crucial roles of PolÉ© and Polκ in conferring TMZ resistance and the potential backup role of homologous recombination in the absence of these TLS polymerases. Targeting these TLS enzymes, along with double-strand break DNA repair inhibition, could, therefore, provide a promising strategy to enhance TMZ's effectiveness in treating GBM.
Assuntos
Metilases de Modificação do DNA , DNA Polimerase iota , Enzimas Reparadoras do DNA , DNA Polimerase Dirigida por DNA , Resistencia a Medicamentos Antineoplásicos , Glioblastoma , Temozolomida , Temozolomida/farmacologia , Humanos , Glioblastoma/genética , Glioblastoma/tratamento farmacológico , Glioblastoma/metabolismo , Glioblastoma/patologia , DNA Polimerase Dirigida por DNA/metabolismo , DNA Polimerase Dirigida por DNA/genética , Linhagem Celular Tumoral , Metilases de Modificação do DNA/metabolismo , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Enzimas Reparadoras do DNA/genética , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/deficiência , Antineoplásicos Alquilantes/farmacologia , Antineoplásicos Alquilantes/uso terapêutico , Dano ao DNA , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Reparo do DNA , Técnicas de Inativação de GenesRESUMO
DNA methyltransferases (DNMTs) play a crucial role in genomic DNA methylation. In mammals, DNMTs regulate the dynamic patterns of DNA methylation in embryonic and adult cells. Abnormal functions of DNMTs are often indicative of cancers, including overall hypomethylation and partial hypermethylation of tumor suppressor genes (TSG), which accelerate the malignancy of tumors, worsen the condition of patients, and significantly exacerbate the difficulty of cancer treatment. Currently, nucleoside DNMT inhibitors such as Azacytidine and Decitabine have been approved by the FDA and EMA for the treatment of acute myeloid leukemia (AML), chronic myelomonocytic leukemia (CMML), and myelodysplastic syndrome (MDS). Therefore, targeting DNMTs is a very promising anti-tumor strategy. This review mainly summarizes the therapeutic effects of DNMT inhibitors on cancers. It aims to provide more possibilities for the treatment of cancers by discovering more DNMT inhibitors with high activity, high selectivity, and good drug-like properties in the future.
Assuntos
Antineoplásicos , Inibidores Enzimáticos , Neoplasias , Humanos , Neoplasias/tratamento farmacológico , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/síntese química , Animais , DNA (Citosina-5-)-Metiltransferases/antagonistas & inibidores , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilases de Modificação do DNA/antagonistas & inibidores , Metilases de Modificação do DNA/metabolismo , Metilação de DNA/efeitos dos fármacos , Estrutura MolecularRESUMO
Gender plays a crucial role in the occurrence and development of cancer, as well as in the metabolism of nutrients and energy. Men and women display significant differences in the incidence, prognosis, and treatment response across various types of cancer, including certain sex-specific tumors. It has been observed that male glioma patients have a higher incidence and worse prognosis than female patients, but there is currently a limited systematic evaluation of sex differences in gliomas. The purpose of this study is to provide an overview of the association between fluctuations in sex hormone levels and changes in their receptor expression with the incidence, progression, treatment, and prognosis of gliomas. Estrogen may have a protective effect on glioma patients, while exposure to androgens increases the risk of glioma. We also discussed the specific genetic and molecular differences between genders in terms of the malignant nature and prognosis of gliomas. Factors such as TP53, MGMT methylation status may play a crucial role. Therefore, it is essential to consider the gender of patients while treating glioma, particularly the differences at the hormonal and molecular levels. This approach can help in the adoption of an individualized treatment strategy.
Assuntos
Neoplasias Encefálicas , Glioma , Hormônios Esteroides Gonadais , Humanos , Glioma/epidemiologia , Glioma/genética , Glioma/patologia , Glioma/metabolismo , Feminino , Masculino , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/epidemiologia , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Fatores Sexuais , Hormônios Esteroides Gonadais/metabolismo , Prognóstico , Incidência , Fatores de Risco , Metilação de DNA , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismoRESUMO
OBJECTIVE: Analysis of long-lived patients from the group of patients with glioblastomas after using photodynamic therapy in the structure of their complex treatment in order to assess the influence of various factors on their life expectancy. MATERIAL AND METHODS: In total, a single-center, retrospective categorical study analyzed the long-term results of treatment of 63 patients with glioblastoma in the structure of complex treatment including photodynamic therapy. Clinical factors (age, sex, number of cases, preoperative Karnofsky index, location and size of the tumor, radicality of the operation), histological (nuclear polymorphism, mitosis, vascular proliferation, necrosis), immunohistochemical (Ki-67, p53 index) molecular-genetic factors (expression of VEGF, MGMT, IDH, CD34), amount of radiation and chemotherapy were analyzed. RESULTS: In the entire group of patients, there was a direct correlation of life expectancy with MGMT status, IDH status, the number of courses of chemotherapy, the age of the patient, and the severity of the first surgical intervention. CONCLUSION: Clinical features such as age at diagnosis and extent of surgical resection and amount of chemotherapy have predictive value in assessing their effect on life expectancy. Mutations in IDH and MGMT promoter methylation were the most important molecular factors determining long-term patient survival.
Assuntos
Neoplasias Encefálicas , Fotoquimioterapia , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Fotoquimioterapia/métodos , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/mortalidade , Estudos Retrospectivos , Adulto , Idoso , Glioblastoma/tratamento farmacológico , Glioblastoma/mortalidade , Glioblastoma/genética , Proteínas Supressoras de Tumor/genética , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismo , Isocitrato Desidrogenase/genética , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Glioma/tratamento farmacológico , Glioma/mortalidade , Glioma/genética , Taxa de Sobrevida , Expectativa de VidaRESUMO
O6-methylguanine DNA methyltransferase (MGMT) is a crucial determinant of temozolomide (TMZ) sensitivity in patients with glioblastoma (GBM). The therapeutic potential of small interfering RNA (siRNA) targeting MGMT to enhance TMZ sensitivity has been hampered by serum nuclease degradation, off-target effects, poor accumulation at tumor sites, and low circulation in blood stream. In this study, we developed a framework nucleic acid-based nanoparticles (FNN), which is constructed from a six-helix DNA bundle, to encapsulate and protect siMGMT for improving TMZ sensitivity in GBM treatment. For better blood-brain barrier (BBB) penetration and GBM targeting, we conjugated Angiopep-2 (ANG) targeting modules to each end of the FNN. Nucleolin (NCL)-responsive locks were engineered along the sides of the six-helix DNA bundle, which safeguard siMGMT before tumor entry. Upon interaction with tumor-overexpressed NCL, these locks unlock, exposing siMGMT, this allows for effective suppression of MGMT, resulting in a significant improvement of TMZ therapeutic efficacy in GBM. This innovative strategy has the potential to transform the current treatment landscape for GBM.
Assuntos
Antineoplásicos Alquilantes , Barreira Hematoencefálica , Neoplasias Encefálicas , Glioblastoma , Nanopartículas , Temozolomida , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Temozolomida/farmacologia , Temozolomida/administração & dosagem , Temozolomida/uso terapêutico , Humanos , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/genética , Antineoplásicos Alquilantes/farmacologia , Antineoplásicos Alquilantes/uso terapêutico , Nanopartículas/química , Animais , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Linhagem Celular Tumoral , Proteínas de Ligação a RNA/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Enzimas Reparadoras do DNA/genética , Metilases de Modificação do DNA/metabolismo , Nucleolina , Fosfoproteínas/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/genética , RNA Interferente Pequeno/administração & dosagem , Ácidos Nucleicos , PeptídeosRESUMO
Background.Glioblastoma Multiforme (GBM) is an aggressive form of malignant brain tumor with a generally poor prognosis.O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation has been shown to be a predictive bio-marker for resistance to treatment of GBM, but it is invasive and time-consuming to determine methylation status. There has been effort to predict the MGMT methylation status through analyzing MRI scans using machine learning, which only requires pre-operative scans that are already part of standard-of-care for GBM patients.Purpose.To improve the performance of conventional transfer learning in the identification of MGMT promoter methylation status, we developed a 3D SpotTune network with adaptive fine-tuning capability. Using the pretrained weights of MedicalNet with the SpotTune network, we compared its performance with a randomly initialized network for different combinations of MR modalities.Methods.Using a ResNet50 as the base network, three categories of networks are created: (1) A 3D SpotTune network to process volumetric MR images, (2) a network with randomly initialized weights, and (3) a network pre-trained on MedicalNet. These three networks are trained and evaluated using a public GBM dataset provided by the University of Pennsylvania. The MRI scans from 240 patients are used, with 11 different modalities corresponding to a set of perfusion, diffusion, and structural scans. The performance is evaluated using 5-fold cross validation with a hold-out testing dataset.Results.The SpotTune network showed better performance than the randomly initialized network. The best performing SpotTune model achieved an area under the Receiver Operating Characteristic curve (AUC), average precision of the precision-recall curve (AP), sensitivity, and specificity values of 0.6604, 0.6179, 0.6667, and 0.6061 respectively.Conclusions.SpotTune enables transfer learning to be adaptive to individual patients, resulting in improved performance in predicting MGMT promoter methylation status in GBM using equivalent MRI modalities as compared to a randomly initialized network.