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BACKGROUND: Platinum resistance is the primary cause of poor survival in ovarian cancer (OC) patients. Targeted therapies and biomarkers of chemoresistance are critical for the treatment of OC patients. Our previous studies identified cell surface CD55, a member of the complement regulatory proteins, drives chemoresistance and maintenance of cancer stem cells (CSCs). CSCs are implicated in tumor recurrence and metastasis in multiple cancers. METHODS: Protein localization assays including immunofluorescence and subcellular fractionation were used to identify CD55 at the cell surface and nucleus of cancer cells. Protein half-life determinations were used to compare cell surface and nuclear CD55 stability. CD55 deletion mutants were generated and introduced into cancer cells to identify the nuclear trafficking code, cisplatin sensitivity, and stem cell frequency that were assayed using in vitro and in vivo models. Detection of CD55 binding proteins was analyzed by immunoprecipitation followed by mass spectrometry. Target pathways activated by CD55 were identified by RNA sequencing. RESULTS: CD55 localizes to the nucleus of a subset of OC specimens, ascites from chemoresistant patients, and enriched in chemoresistant OC cells. We determined that nuclear CD55 is glycosylated and derived from the cell surface pool of CD55. Nuclear localization is driven by a trafficking code containing the serine/threonine (S/T) domain of CD55. Nuclear CD55 is necessary for cisplatin resistance, stemness, and cell proliferation in OC cells. CD55 S/T domain is necessary for nuclear entry and inducing chemoresistance to cisplatin in both in vitro and in vivo models. Deletion of the CD55 S/T domain is sufficient to sensitize chemoresistant OC cells to cisplatin. In the nucleus, CD55 binds and attenuates the epigenetic regulator and tumor suppressor ZMYND8 with a parallel increase in H3K27 trimethylation and members of the Polycomb Repressive Complex 2. CONCLUSIONS: For the first time, we show CD55 localizes to the nucleus in OC and promotes CSC and chemoresistance. Our studies identify a therapeutic mechanism for treating platinum resistant ovarian cancer by blocking CD55 nuclear entry.
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Antígenos CD55 , Núcleo Celular , Cromatina , Cisplatino , Resistencia a Medicamentos Antineoplásicos , Histonas , Células-Tronco Neoplásicas , Neoplasias Ovarianas , Humanos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/genética , Feminino , Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Animais , Camundongos , Antígenos CD55/metabolismo , Antígenos CD55/genética , Linhagem Celular Tumoral , Histonas/metabolismo , Núcleo Celular/metabolismo , Cromatina/metabolismo , Metilação , Ensaios Antitumorais Modelo de Xenoenxerto , Antineoplásicos/farmacologia , Transporte ProteicoRESUMO
BACKGROUND: Single session stereotactic radiosurgery (SRS) or surgical resection alone for brain metastases larger than 2 cm results in unsatisfactory local control. We conducted a phase I trial for brain metastases(>2cm) to determine the safety of preoperative SRS at escalating doses. METHODS: Radiosurgery dose was escalated at 3 Gy increments for 3 cohorts based on maximum tumor dimension starting at: 18 Gy for >2-3 cm, 15 Gy for >3-4 cm, and 12 Gy for >4-6 cm. Dose limiting toxicity (DLT) was defined as grade III or greater acute toxicity. RESULTS: A total of 35 patients/36 lesions were enrolled. For tumor size >2-3 cm, patients were enrolled up to the second dose level (21 Gy); for >3-4 cm and >4-6 cm cohorts the third dose level (21 Gy and 18 Gy, respectively) was reached. There were 2 DLTs in the >3-4 cm arm at 21Gy. The maximum tolerated dose (MTD) of SRS for >2-3 cm was not reached; and was 18 Gy for both >3-4 cm arm and >4-6 cm arm. With a median follow-up of 64.0 months, the 6- and 12-month local control rates were 85.9% and 76.6%, respectively. One patient developed grade 3 radiation necrosis at 5 months. The 2-year rate of leptomeningeal disease (LMD) was 0%. CONCLUSION: Preoperative SRS with dose escalation followed by surgical resection for brain metastases greater than 2 cm in size demonstrates acceptable acute toxicity. The phase II portion of the trial will be conducted at the maximum tolerated SRS doses.
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BACKGROUND: Hypoxia is associated with poor prognosis in many cancers including glioblastoma (GBM). Glioma stem-like cells (GSCs) often reside in hypoxic regions and serve as reservoirs for disease progression. Long non-coding RNAs (lncRNAs) have been implicated in GBM. However, the lncRNAs that modulate GSC adaptations to hypoxia are poorly understood. Identification of these lncRNAs may provide new therapeutic strategies to target GSCs under hypoxia. METHODS: lncRNAs induced by hypoxia in GSCs were identified by RNA-seq. Lung cancer-associated transcript-1 (LUCAT1) expression was assessed by qPCR, RNA-seq, Northern blot, single molecule FISH in GSCs, and interrogated in IvyGAP, The Cancer Genome Atlas, and CGGA databases. LUCAT1 was depleted by shRNA, CRISPR/Cas9, and CRISPR/Cas13d. RNA-seq, Western blot, immunohistochemistry, co-IP, ChIP, ChIP-seq, RNA immunoprecipitation, and proximity ligation assay were performed to investigate mechanisms of action of LUCAT1. GSC viability, limiting dilution assay, and tumorigenic potential in orthotopic GBM xenograft models were performed to assess the functional consequences of depleting LUCAT1. RESULTS: A new isoform of Lucat1 is induced by Hypoxia inducible factor 1 alpha (HIF1α) and Nuclear factor erythroid 2-related factor 2 (NRF2) in GSCs under hypoxia. LUCAT1 is highly expressed in hypoxic regions in GBM. Mechanistically, LUCAT1 formed a complex with HIF1α and its co-activator CBP to regulate HIF1α target gene expression and GSC adaptation to hypoxia. Depletion of LUCAT1 impaired GSC self-renewal. Silencing LUCAT1 decreased tumor growth and prolonged mouse survival in GBM xenograft models. CONCLUSIONS: A HIF1α-LUCAT1 axis forms a positive feedback loop to amplify HIF1α signaling in GSCs under hypoxia. LUCAT1 promotes GSC self-renewal and GBM tumor growth. LUCAT1 is a potential therapeutic target in GBM.
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Neoplasias Encefálicas , Regulação Neoplásica da Expressão Gênica , Glioblastoma , Subunidade alfa do Fator 1 Induzível por Hipóxia , RNA Longo não Codificante , Humanos , RNA Longo não Codificante/genética , Glioblastoma/metabolismo , Glioblastoma/patologia , Glioblastoma/genética , Animais , Camundongos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Progressão da Doença , Ensaios Antitumorais Modelo de Xenoenxerto , Proliferação de Células , Células Tumorais Cultivadas , Camundongos Nus , Linhagem Celular Tumoral , Biomarcadores Tumorais/metabolismo , Biomarcadores Tumorais/genética , Prognóstico , ApoptoseRESUMO
Advances in molecular characterization have reshaped our understanding of low-grade glioma (LGG) subtypes, emphasizing the need for comprehensive classification beyond histology. Lever-aging this, we present a novel approach, network-based Subnetwork Enumeration, and Analysis (nSEA), to identify distinct LGG patient groups based on dysregulated molecular pathways. Using gene expression profiles from 516 patients and a protein-protein interaction network we generated 25 million sub-networks. Through our unsupervised bottom-up approach, we selected 92 subnetworks that categorized LGG patients into five groups. Notably, a new LGG patient group with a lack of mutations in EGFR, NF1, and PTEN emerged as a previously unidentified patient subgroup with unique clinical features and subnetwork states. Validation of the patient groups on an independent dataset demonstrated the robustness of our approach and revealed consistent survival traits across different patient populations. This study offers a comprehensive molecular classification of LGG, providing insights beyond traditional genetic markers. By integrating network analysis with patient clustering, we unveil a previously overlooked patient subgroup with potential implications for prognosis and treatment strategies. Our approach sheds light on the synergistic nature of driver genes and highlights the biological relevance of the identified subnetworks. With broad implications for glioma research, our findings pave the way for further investigations into the mechanistic underpinnings of LGG subtypes and their clinical relevance.Availability: Source code and supplementary data are available at https://github.com/bebeklab/nSEA.
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Neoplasias Encefálicas , Glioma , Humanos , Prognóstico , Biologia Computacional , Glioma/genética , Glioma/patologia , Algoritmos , Mapas de Interação de Proteínas , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologiaRESUMO
The glioblastoma microenvironment is enriched in immunosuppressive factors that potently interfere with the function of cytotoxic T lymphocytes. Cancer cells can directly impact the immune system, but the mechanisms driving these interactions are not completely clear. Here we demonstrate that the polyamine metabolite spermidine is elevated in the glioblastoma tumor microenvironment. Exogenous administration of spermidine drives tumor aggressiveness in an immune-dependent manner in pre-clinical mouse models via reduction of CD8+ T cell frequency and phenotype. Knockdown of ornithine decarboxylase, the rate-limiting enzyme in spermidine synthesis, did not impact cancer cell growth in vitro but did result in extended survival. Furthermore, glioblastoma patients with a more favorable outcome had a significant reduction in spermidine compared to patients with a poor prognosis. Our results demonstrate that spermidine functions as a cancer cell-derived metabolite that drives tumor progression by reducing CD8+T cell number and function.
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PURPOSE: Distinguishing radiation necrosis from tumor progression among patients with brain metastases previously treated with stereotactic radiosurgery represents a common diagnostic challenge. We performed a prospective pilot study to determine whether PET/CT with 18F-fluciclovine, a widely available amino acid PET radiotracer, repurposed intracranially, can accurately diagnose equivocal lesions. METHODS: Adults with brain metastases previously treated with radiosurgery presenting with a follow-up tumor-protocol MRI brain equivocal for radiation necrosis versus tumor progression underwent an 18F-fluciclovine PET/CT of the brain within 30 days. The reference standard for final diagnosis consisted of clinical follow-up until multidisciplinary consensus or tissue confirmation. RESULTS: Of 16 patients imaged from 7/2019 to 11/2020, 15 subjects were evaluable with 20 lesions (radiation necrosis, n = 16; tumor progression, n = 4). Higher SUVmax statistically significantly predicted tumor progression (AUC = 0.875; p = 0.011). Lesion SUVmean (AUC = 0.875; p = 0.018), SUVpeak (AUC = 0.813; p = 0.007), and SUVpeak-to-normal-brain (AUC = 0.859; p = 0.002) also predicted tumor progression, whereas SUVmax-to-normal-brain (p = 0.1) and SUVmean-to-normal-brain (p = 0.5) did not. Qualitative visual scores were significant predictors for readers 1 (AUC = 0.750; p < 0.001) and 3 (AUC = 0.781; p = 0.045), but not for reader 2 (p = 0.3). Visual interpretations were significant predictors for reader 1 (AUC = 0.898; p = 0.012) but not for reader 2 (p = 0.3) or 3 (p = 0.2). CONCLUSIONS: In this prospective pilot study of patients with brain metastases previously treated with radiosurgery presenting with a contemporary MRI brain with a lesion equivocal for radiation necrosis versus tumor progression, 18F-fluciclovine PET/CT repurposed intracranially demonstrated encouraging diagnostic accuracy, supporting the pursuit of larger clinical trials which will be necessary to establish diagnostic criteria and performance.
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Neoplasias Encefálicas , Radiocirurgia , Adulto , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Radiocirurgia/efeitos adversos , Projetos Piloto , Estudos Prospectivos , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/etiologia , Necrose/diagnóstico por imagem , Necrose/etiologiaRESUMO
In the United States, an individual's access to resources, insurance status, and wealth are critical social determinants that affect both the risk and outcomes of many diseases. One disease for which the correlation with socioeconomic status (SES) is less well-characterized is glioblastoma (GBM), a devastating brain malignancy. The aim of this study was to review the current literature characterizing the relationship between area-level SES and both GBM incidence and prognosis in the United States. A query of multiple databases was performed to identify the existing data on SES and GBM incidence or prognosis. Papers were filtered by relevant terms and topics. A narrative review was then constructed to summarize the current body of knowledge on this topic. We obtained a total of three papers that analyze SES and GBM incidence, which all report a positive correlation between area-level SES and GBM incidence. In addition, we found 14 papers that focus on SES and GBM prognosis, either overall survival or GBM-specific survival. Those studies that analyze data from greater than 1,530 patients report a positive correlation between area-level SES and individual prognosis, while those with smaller study populations report no significant relationship. Our report underlines the strong association between SES and GBM incidence and highlights the need for large study populations to assess SES and GBM prognosis to ideally guide interventions that improve outcomes. Further studies are needed to determine underlying socio-economic stresses on GBM risk and outcomes to identify opportunities for intervention.
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The Wnt pathway is frequently dysregulated in many cancers, underscoring it as a therapeutic target. Wnt inhibitors have uniformly failed in clinical trials. Here, we report a mechanism of WNT pathway activation through the Semaphorin 3 C neurodevelopmental program in glioma stem-like cells. Sema3C directs ß-catenin nuclear accumulation in a Rac1-dependent process, leading to transactivation of Wnt target genes. Sema3C-driven Wnt signaling occurred despite suppression of Wnt ligand secretion, suggesting that Sema3C drives canonical Wnt signaling independent of Wnt ligand binding. In a mouse model of glioblastoma, combined depletion of Sema3C and ß-catenin partner TCF1 extended animal survival more than single target inhibition alone. In human glioblastoma, Sema3C expression and Wnt pathway activation were highly concordant. Since Sema3C is frequently overexpressed in glioblastoma, Sema3C signaling may be a significant mechanism of resistance to upstream Wnt pathway inhibitors. Dual targeting of Sema3C and Wnt pathways may achieve clinically significant Wnt pathway inhibition.
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Glioblastoma , Semaforinas , Animais , Humanos , Camundongos , beta Catenina/genética , beta Catenina/metabolismo , Linhagem Celular Tumoral , Glioblastoma/genética , Glioblastoma/metabolismo , Ligantes , Semaforinas/genética , Via de Sinalização Wnt/genéticaRESUMO
Brain metastases are a significant source of morbidity and mortality in patients with non-small cell lung cancer. Historically, surgery and radiation therapy have been essential to maintaining disease control within the central nervous system due to poorly penetrant conventional chemotherapy. With the advent of targeted therapy against actionable driver mutations, there is potential to control limited and asymptomatic intracranial disease and delay local therapy until progression. In this review paper, intracranial response rates and clinical outcomes to biological and immune therapies are summarized from the literature and appraised to assist clinical decision making and identify areas for further research. Future clinical trials ought to prioritize patient-centered quality of life and neurocognitive measures as major outcomes and specifically stratify patients based on mutational marker status, disease burden, and symptom acuity.
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Despite therapeutic interventions for glioblastoma (GBM), cancer stem cells (CSCs) drive recurrence. The precise mechanisms underlying CSC resistance, namely inhibition of cell death, are unclear. We built on previous observations that the high cell surface expression of junctional adhesion molecule-A drives CSC maintenance and identified downstream signaling networks, including the cysteine protease inhibitor SerpinB3. Using genetic depletion approaches, we found that SerpinB3 is necessary for CSC maintenance, survival, and tumor growth, as well as CSC pathway activation. Knockdown of SerpinB3 also increased apoptosis and susceptibility to radiation therapy. SerpinB3 was essential to buffer cathepsin L-mediated cell death, which was enhanced with radiation. Finally, we found that SerpinB3 knockdown increased the efficacy of radiation in pre-clinical models. Taken together, our findings identify a GBM CSC-specific survival mechanism involving a cysteine protease inhibitor, SerpinB3, and provide a potential target to improve the efficacy of GBM therapies against therapeutically resistant CSCs.
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Glioblastoma , Inibidores de Cisteína Proteinase/metabolismo , Inibidores de Cisteína Proteinase/uso terapêutico , Glioblastoma/patologia , Humanos , Células-Tronco Neoplásicas/metabolismo , Transdução de SinaisRESUMO
Pediatric high-grade gliomas (pHGGs) are the leading cause of cancer-related deaths in children in the USA. Sixteen percent of hemispheric pediatric and young adult HGGs encode Gly34Arg/Val substitutions in the histone H3.3 (H3.3-G34R/V). The mechanisms by which H3.3-G34R/V drive malignancy and therapeutic resistance in pHGGs remain unknown. Using a syngeneic, genetically engineered mouse model (GEMM) and human pHGG cells encoding H3.3-G34R, we demonstrate that this mutation led to the downregulation of DNA repair pathways. This resulted in enhanced susceptibility to DNA damage and inhibition of the DNA damage response (DDR). We demonstrate that genetic instability resulting from improper DNA repair in G34R-mutant pHGG led to the accumulation of extrachromosomal DNA, which activated the cyclic GMP-AMP synthase/stimulator of IFN genes (cGAS/STING) pathway, inducing the release of immune-stimulatory cytokines. We treated H3.3-G34R pHGG-bearing mice with a combination of radiotherapy (RT) and DNA damage response inhibitors (DDRi) (i.e., the blood-brain barrier-permeable PARP inhibitor pamiparib and the cell-cycle checkpoint CHK1/2 inhibitor AZD7762), and these combinations resulted in long-term survival for approximately 50% of the mice. Moreover, the addition of a STING agonist (diABZl) enhanced the therapeutic efficacy of these treatments. Long-term survivors developed immunological memory, preventing pHGG growth upon rechallenge. These results demonstrate that DDRi and STING agonists in combination with RT induced immune-mediated therapeutic efficacy in G34-mutant pHGG.
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Neoplasias Encefálicas , Citocinas , Reparo do DNA , Glioma , Histonas , Proteínas de Membrana , Nucleotidiltransferases , Animais , Criança , Humanos , Camundongos , Adulto Jovem , Neoplasias Encefálicas/genética , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/genética , Glioma/genética , Histonas/genética , Imunidade , Mutação , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Citocinas/imunologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêuticoRESUMO
PURPOSE: In addition to established prognostic factors in low-grade glioma (LGG), studies suggest a sexual dimorphism with male sex portending worse prognosis. Our objective was to identify the effect of sex on presentation and outcomes in LGG. METHODS AND MATERIALS: We conducted a retrospective cohort study of adults (aged ≥18 years) diagnosed with LGG (World Health Organization 2016 grade 2 glioma). Patients with IDH wild-type tumors were excluded. Patients were matched between male and female sex by age, treatment, and surgery via propensity score matching. Patient, tumor, and treatment characteristics were analyzed by sex. Endpoints included overall survival (OS), next intervention-free survival (NIFS), progression-free survival, and malignant transformation-free survival. Kaplan-Meier analyses and Cox proportional hazards regression multivariable analysis with backward elimination were completed. RESULTS: Of the 532 patients identified, 258 (48%) were men. Men were more likely to present with seizure (69.38% vs 56.57%, P = .002), but no other statistically significant differences between sexes at presentation were identified. Five-year OS was higher in women at 87% (95% confidence interval [CI], 83%-91%) versus 78% (95% CI, 73%-84%) in men (P = .0045). NIFS was significantly higher in female patients at 68% (95% CI, 62%-74%) versus 57% (95% CI, 51%-64%) in men (P = .009). On multivariable analysis, female sex was independently associated with improved OS (hazard ratio [HR], 1.54; 95% CI, 1.16-2.05; P = .002), NIFS (HR, 1.42; 95% CI, 1.42; P = .004), and malignant transformation-free survival (HR, 1.62; 95% CI, 1.24-2.12; P = .0004). In patients with molecularly defined LGG (IDH and 1p19q status; n = 291), female sex remained independently associated with improved OS (HR, 1.79; 95% CI, 1.16-2.77; P = .008) and NIFS (HR, 1.45; 95% CI, 1.07-1.96; P = .016). CONCLUSIONS: In this study, female sex was independently associated with improved outcomes. These findings support intrinsic sex-specific differences in LGG behavior, justifying further studies to optimize management and therapeutics based on sex.
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Neoplasias Encefálicas , Glioma , Adolescente , Adulto , Neoplasias Encefálicas/patologia , Feminino , Glioma/patologia , Humanos , Masculino , Prognóstico , Estudos Retrospectivos , Caracteres SexuaisRESUMO
PURPOSE: We sought to evaluate the effects of concurrent temozolomide-based chemoradiation therapy on neurocognitive function in patients with low-grade glioma (LGG). MATERIALS/METHODS: We included adult patients with LGG who were treated postoperatively with radiotherapy (RT) with concurrent and adjuvant temozolomide (TMZ). Patients were evaluated with comprehensive psychometric tests at baseline (prior to RT + TMZ) and at various time intervals following RT + TMZ. Baseline cognitive performance was analyzed by sex, age, education history, history of seizures, IDH mutation status, and 1p/19q codeletion status. Changes in neurocognitive performance were evaluated over time. RESULTS: Thirty-seven LGG patients (mean age 43.6, 59.5% male) had baseline neurocognitive evaluation. Patients with an age > 40 years old at diagnosis and those with an education > 16 years demonstrated superior baseline verbal memory as assessed by HVLT. No other cognitive domains showed differences when stratified by the variables mentioned above. A total of 22 LGG patients had baseline and post RT + TMZ neurocognitive evaluation. Overall, patients showed no statistical difference between group mean test scores prior to and following RT + TMZ on all psychometric measures (with the exception of HVLT Discrimination). CONCLUSION: Cognitive function remained stable following RT + TMZ in LGG patients evaluated prospectively up to 2 years. The anticipated analysis of RTOG 0424 will provide valuable neurocognitive outcomes specifically for high risk LGG patients treated with RT + TMZ.
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Neoplasias Encefálicas , Glioma , Adulto , Antineoplásicos Alquilantes/uso terapêutico , Neoplasias Encefálicas/genética , Cognição , Feminino , Glioma/genética , Humanos , Masculino , Temozolomida/uso terapêuticoRESUMO
PURPOSE: Low-grade glioma (LGG) exhibits longer median survival than high-grade brain tumors, and thus impact of our therapies on patient quality of life remains a crucial consideration. This study evaluated the effects of concurrent temozolomide-based chemoradiation (RT + TMZ) or observation on quality of life (QOL) in patients with low-grade glioma. METHODS: We completed a retrospective cross-sectional study of adults with LGG who underwent surgery with known molecular classification from 1980 to 2018. Postoperatively, patients were either observed or received adjuvant concurrent temozolomide-based chemoradiation. EQ-5D and PHQ-9 depression screen were completed before outpatient visits every 2-3 months. Baseline score was defined as ± 30 days within initial operation. RESULTS: Of the 63 patients (mean age 44 ± 17 years, 51% female) with baseline EQ-5D or PHQ-9 depression screen data and at least one follow-up measure, 30 (48%) were observed and 33 (52%) received RT + TMZ. No significant decline was seen in EQ-5D or PHQ-9 scores at 3, 6, 9, 12, and 24 months compared to baseline scores for all patients. At each time point, there was no significant difference between those who were observed or received adjuvant therapy. The linear mixed model estimating PHQ-9 value or EQ-5D index demonstrated that there was no significant difference in PHQ-9 or EQ-5D index between treatment groups (p = 0.42 and p = 0.54, respectively) or time points (p = 0.24 and p = 0.99, respectively). CONCLUSION: Our study found no significant decline in patient QOL or depression scores as assessed by patient- reported outcome measures for patients with low-grade glioma up to 2 years following surgery. We found no difference between RT + TMZ compared to observation during this time frame. Additional follow-up can help identify the longer-term impact of treatment strategy on patient experience.
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Neoplasias Encefálicas , Quimiorradioterapia , Glioma , Qualidade de Vida , Temozolomida , Conduta Expectante , Adulto , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/terapia , Estudos Transversais , Feminino , Glioma/patologia , Glioma/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Estudos Retrospectivos , Temozolomida/uso terapêutico , Resultado do TratamentoRESUMO
Signaling of semaphorin ligands via their plexin-neuropilin receptors is involved in tissue patterning in the developing embryo. These proteins play roles in cell migration and adhesion but are also important in disease etiology, including in cancer angiogenesis and metastasis. While some structures of the soluble domains of these receptors have been determined, the conformations of the full-length receptor complexes are just beginning to be elucidated, especially within the context of the plasma membrane. Pulsed-interleaved excitation fluorescence cross-correlation spectroscopy allows direct insight into the formation of protein-protein interactions in the membranes of live cells. Here, we investigated the homodimerization of neuropilin-1 (Nrp1), plexin A2, plexin A4, and plexin D1 using pulsed-interleaved excitation fluorescence cross-correlation spectroscopy. Consistent with previous studies, we found that Nrp1, plexin A2, and plexin A4 are present as dimers in the absence of exogenous ligand. Plexin D1, on the other hand, was monomeric under similar conditions, which had not been previously reported. We also found that plexin A2 and A4 assemble into a heteromeric complex. Stimulation with semaphorin 3A or semaphorin 3C neither disrupts nor enhances the dimerization of the receptors when expressed alone, suggesting that activation involves a conformational change rather than a shift in the monomer-dimer equilibrium. However, upon stimulation with semaphorin 3C, plexin D1 and Nrp1 form a heteromeric complex. This analysis of interactions provides a complementary approach to the existing structural and biochemical data that will aid in the development of new therapeutic strategies to target these receptors in cancer.
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Moléculas de Adesão Celular , Proteínas do Tecido Nervoso , Semaforinas , Membrana Celular/metabolismo , Movimento Celular , Humanos , Transdução de SinaisRESUMO
Glioblastoma (GBM), a lethal primary brain tumor, contains glioma stem cells (GSCs) that promote malignant progression and therapeutic resistance. SOX2 is a core transcription factor that maintains the properties of stem cells, including GSCs, but mechanisms associated with posttranslational SOX2 regulation in GSCs remain elusive. Here, we report that DNA-dependent protein kinase (DNA-PK) governs SOX2 stability through phosphorylation, resulting in GSC maintenance. Mass spectrometric analyses of SOX2-binding proteins showed that DNA-PK interacted with SOX2 in GSCs. The DNA-PK catalytic subunit (DNA-PKcs) was preferentially expressed in GSCs compared to matched non-stem cell tumor cells (NSTCs) isolated from patient-derived GBM xenografts. DNA-PKcs phosphorylated human SOX2 at S251, which stabilized SOX2 by preventing WWP2-mediated ubiquitination, thus promoting GSC maintenance. We then demonstrated that when the nuclear DNA of GSCs either in vitro or in GBM xenografts in mice was damaged by irradiation or treatment with etoposide, the DNA-PK complex dissociated from SOX2, which then interacted with WWP2, leading to SOX2 degradation and GSC differentiation. These results suggest that DNA-PKcs-mediated phosphorylation of S251 was critical for SOX2 stabilization and GSC maintenance. Pharmacological inhibition of DNA-PKcs with the DNA-PKcs inhibitor NU7441 reduced GSC tumorsphere formation in vitro and impaired growth of intracranial human GBM xenografts in mice as well as sensitized the GBM xenografts to radiotherapy. Our findings suggest that DNA-PK maintains GSCs in a stem cell state and that DNA damage triggers GSC differentiation through precise regulation of SOX2 stability, highlighting that DNA-PKcs has potential as a therapeutic target in glioblastoma.
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Neoplasias Encefálicas/radioterapia , Proteína Quinase Ativada por DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/antagonistas & inibidores , Glioblastoma/radioterapia , Glioma/radioterapia , Animais , Neoplasias Encefálicas/genética , Diferenciação Celular , Linhagem Celular Tumoral , Camundongos , Células-Tronco Neoplásicas , Fatores de Transcrição SOXB1RESUMO
Patients with glioblastoma (GBM) need bold new approaches to their treatment, yet progress has been hindered by a relative inability to dynamically track treatment response, mechanisms of resistance, evolution of targetable mutations, and changes in mutational burden. We are writing on behalf of a multidisciplinary group of academic neuro-oncology professionals who met at the collaborative Christopher Davidson Forum at Washington University in St Louis in the fall of 2019. We propose a dramatic but necessary change to the routine management of patients with GBM to advance the field: to routinely biopsy recurrent GBM at the time of presumed recurrence. Data derived from these samples will identify true recurrence vs treatment effect, avoid treatments with little chance of success, enable clinical trial access, and aid in the scientific advancement of our understanding of GBM.
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Neoplasias Encefálicas , Glioblastoma , Biópsia , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Glioblastoma/diagnóstico , Glioblastoma/genética , Glioblastoma/terapia , Humanos , Mutação , Recidiva Local de Neoplasia/diagnósticoRESUMO
Piwi proteins are a subfamily of Argonaute proteins that maintain germ cells in eukaryotes. However, the role of their human homologs in cancer stem cells, and more broadly in cancer, is poorly understood. Here, we report that Piwi-like family members are overexpressed in glioblastoma (GBM), with Piwil1 (Hiwi) most frequently overexpressed (88%). Piwil1 is enriched in glioma stem-like cells (GSCs) to maintain self-renewal. Silencing Piwil1 in GSCs leads to global changes in gene expression resulting in cell-cycle arrest, senescence, or apoptosis. Piwil1 knockdown increases expression of the transcriptional co-regulator BTG2 and the E3-ubiquitin ligase FBXW7, leading to reduced c-Myc expression, as well as loss of expression of stem cell factors Olig2 and Nestin. Piwil1 regulates mRNA stability of BTG2, FBXW7, and CDKN1B. In animal models of GBM, Piwil1 knockdown suppresses tumor growth and promotes mouse survival. These findings support a role of Piwil1 in GSC maintenance and glioblastoma progression.
Assuntos
Proteínas Argonautas/metabolismo , Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Glioma/metabolismo , Proteínas Imediatamente Precoces/metabolismo , Células-Tronco Neoplásicas/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Proteínas Argonautas/genética , Neoplasias Encefálicas/genética , Ciclo Celular , Linhagem Celular , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Glioblastoma/genética , Glioma/genética , Humanos , Masculino , Camundongos , Nestina/metabolismo , Fator de Transcrição 2 de Oligodendrócitos/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Estabilidade de RNARESUMO
Cisplatin chemotherapy is standard care for many cancers but is toxic to the kidneys. How this toxicity occurs is uncertain. In this study, we identified apurinic/apyrimidinic endonuclease 2 (APE2) as a critical molecule upregulated in the proximal tubule cells (PTC) following cisplatin-induced nuclear DNA and mitochondrial DNA damage in cisplatin-treated C57B6J mice. The APE2 transgenic mouse phenotype recapitulated the pathophysiological features of C-AKI (acute kidney injury, AKI) in the absence of cisplatin treatment. APE2 pulldown-MS analysis revealed that APE2 binds myosin heavy-Chain 9 (MYH9) protein in mitochondria after cisplatin treatment. Human MYH9-related disorder is caused by mutations in MYH9 that eventually lead to nephritis, macrothrombocytopenia, and deafness, a constellation of symptoms similar to the toxicity profile of cisplatin. Moreover, cisplatin-induced C-AKI was attenuated in APE2-knockout mice. Taken together, these findings suggest that cisplatin promotes AKI development by upregulating APE2, which leads to subsequent MYH9 dysfunction in PTC mitochondria due to an unrelated role of APE2 in DNA damage repair. This postulated mechanism and the availability of an engineered transgenic mouse model based on the mechanism of C-AKI provides an opportunity to identify novel targets for prophylactic treatment of this serious disease. SIGNIFICANCE: These results reveal and highlight an unexpected role of APE2 via its interaction with MYH9 and suggest that APE2 has the potential to prevent acute kidney injury in patients with cisplatin-treated cancer. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/3/713/F1.large.jpg.